KR20170026201A - Motor-driven compressor - Google Patents

Abstract

A motor-driven compressor includes: an electric motor including a rotor; a housing; a compression unit; a drive circuit; and a controller. The controller includes: a deceleration controller that performs a deceleration control, which decelerates the rotor, during a first period in response to the rotor being rotating in a direction opposite to the forward direction; and a continuation controller that performs a continuation control, which continues the rotation of the rotor, during a second period that is longer than the first period after the deceleration control is performed. A fluctuation difference of a rotational frequency of the rotor during the continuation control is less than a deceleration rotational frequency difference.

Description

[0001] MOTOR-DRIVEN COMPRESSOR [0002]

The present invention relates to an electric compressor.

For example, Japanese Unexamined Patent Publication (Kokai) No. 2003-120555 discloses a compressor having a compressor having a movable scroll capable of orbital motion with respect to fixed scroll and fixed scroll, and an electric compressor having an electric motor for revolving the movable scroll Lt; / RTI > The motor-driven compressor has a compression chamber partitioned by the fixed scroll and the movable scroll, in which the suction fluid is sucked, and the movable scroll performs idle motion to compress the suction fluid in the compression chamber and to discharge the compressed fluid.

Japanese Unexamined Patent Application Publication No. 2003-120555 discloses an air compressor in which an injection port for introducing an intermediate pressure fluid of a higher pressure than a suction fluid is formed in a compression chamber and an air conditioner having the electric compressor. The air conditioning apparatus includes, for example, an injection pipe connected to an injection port and a gas-liquid separator connected to an injection pipe. The intermediate-pressure fluid separated by the gas-liquid separator flows into the compression chamber through the injection pipe and the injection port, thereby increasing the flow rate of the fluid flowing into the compression chamber.

In the configuration in which the intermediate-pressure fluid as described above is introduced into the compression chamber, the intermediate-pressure fluid remaining in the injection pipe sometimes flows into the compression chamber through the injection port at the time of stopping the operation of the electric compressor. In this case, the movable scroll may revolve in the opposite direction to the forward direction, and the rotor may also rotate in the reverse direction. In this case, if the number of revolutions (rotation speed) of the rotor is high, noise and vibration tend to increase.

Here, in order to stop the rotor at an early stage, it is conceivable to perform forcible stop control for forcibly stopping the reverse rotation of the rotor, for example, to the electric motor. In this case, a situation may occur in which the intermediate-pressure fluid remains in the injection pipe. Then, there is a possibility that the re-circulation phenomenon occurs in which the rotor rotates again after the rotation of the rotor is stopped by the intermediate-pressure fluid. If this re-circulation phenomenon occurs, for example, a trouble may occur at the start of the motor-driven compressor.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric compressor capable of suppressing occurrence of a re-rotation phenomenon while suppressing noise or vibration.

An electric compressor for achieving the above object is provided with an electric motor having a rotor, a housing having a suction port through which fluid is sucked, and a compressor driven by the electric motor to compress the suction fluid, which is the fluid sucked from the suction port, And a controller for controlling the rotation of the rotor by controlling the driving circuit. The motor-driven compressor according to claim 1, The compression section includes a fixed scroll fixed to the housing, a movable scroll engaged with the fixed scroll and configured to revolve with respect to the fixed scroll, and a compression chamber partitioned by the fixed scroll and the movable scroll, When the rotor rotates in the predetermined forward direction, the movable scroll is moved in the forward direction The compression section compresses the suction fluid sucked into the compression chamber, and the motor compressor introduces an intermediate-pressure fluid, which is higher in pressure than the suction fluid and lower in pressure than the compression fluid, into the compression chamber Wherein the control unit includes a deceleration control unit that performs deceleration control for decelerating the rotor over a first period as the rotor rotates in a direction opposite to the forward direction, And a continuation control section for performing continuation control to continue the rotation of the rotor over a second period longer than the first period after the deceleration control, When the number of revolutions of the rotor at the start timing and the number of revolutions of the rotor at the end timing of the deceleration control A deceleration smaller than the rotation speed difference.

1 is a schematic cross-sectional view of an electric compressor.
2 is a cross-sectional view of a compression unit included in the motor-driven compressor of FIG.
3 is a schematic view of a vehicle air conditioning apparatus.
4 is a circuit diagram showing the electrical configuration of the inverter.
Fig. 5 is a time chart of the lower arm switching element in the one-phase pattern, in which (a) shows ON / OFF of the u-phase lower arm switching element, (C) shows ON / OFF of the w-phase lower arm switching element.
6 is a graph schematically showing each phase current when the rotor is rotating in the forward direction.
7 is a graph schematically showing each phase current when the rotor is rotating in a direction opposite to the forward direction.
8 is a flowchart showing the reverse rotation control process.
Fig. 9 is a time chart of the lower arm switching element in the two-phase pattern, in which (a) shows ON / OFF of the u-phase lower arm switching element, (C) shows ON / OFF of the w-phase lower arm switching element.
10 is a graph showing the change over time of the number of revolutions of the rotor after stopping the operation.

Hereinafter, an embodiment of the electric compressor will be described.

As shown in Fig. 1, the motor-driven compressor 10 includes a housing 11 having a suction port 11a through which fluid is sucked and a discharge port 11b through which fluid is discharged. The housing 11 is generally cylindrical in shape. Specifically, the housing 11 has a first part 12 and a second part 13, and each has a cylindrical shape having a bottom part and an opening end. The first part 12 and the second part 13 are installed so that their opening ends are in contact with each other. The suction port 11a is formed in the vicinity of the side wall portion 12a of the first part 12 and more particularly the bottom part 12b of the first part 12 of the side wall part 12a. The discharge port 11b is formed in the bottom portion 13a of the second part 13.

The motor-driven compressor 10 includes a rotary shaft 14, a compression unit 15 that compresses the fluid sucked from the suction port 11a, that is, the suction fluid, and discharges the compressed fluid from the discharge port 11b, And a motor (16). The rotary shaft 14, the compression section 15, and the electric motor 16 are accommodated in the housing 11. The electric motor 16 is disposed in the housing 11 on the side corresponding to the suction port 11a and the compressed portion 15 is disposed on the side corresponding to the discharge port 11b in the housing 11 have.

The rotary shaft (14) is accommodated in the housing (11) in a rotatable state. Specifically, a shaft supporting member 21 for axially supporting the rotary shaft 14 is formed in the housing 11. As shown in Fig. The shaft support member 21 is fixed to the housing 11 at a position between the compression section 15 and the electric motor 16, for example. The shaft support member 21 is formed with a through hole 23 through which the rotation shaft 14 can be inserted and in which the first bearing 22 is formed. The shaft supporting member 21 and the bottom portion 12b of the first part 12 are opposed to each other and a cylindrical boss 24 protrudes from the bottom portion 12b. A second bearing (25) is formed on the inner side of the boss (24). The rotary shaft 14 is rotatably supported by the first bearing 22 and the second bearing 25.

The compression section 15 includes a fixed scroll 31 fixed to the housing 11 and a movable scroll 32 capable of idle movement relative to the fixed scroll 31.

The fixed scroll 31 has a disk-like fixed substrate 31a formed on the same axis as the rotating shaft 14 and a fixed vortex wall 31b rising from the fixed substrate 31a. Likewise, the movable scroll 32 is provided with a movable substrate 32a on a disk and opposed to the fixed substrate 31a, and a movable swirl wall 32b rising from the movable substrate 32a toward the fixed substrate 31a have.

As shown in Figs. 1 and 2, the fixed scroll 31 and the movable scroll 32 are engaged with each other. More specifically, the stationary swirl wall 31b and the movable swirl wall 32b are engaged with each other. The distal end surface of the stationary swirl wall 31b contacts the movable substrate 32a, and the movable swirl wall 32b, Is in contact with the fixed substrate 31a. The compression chamber (33) is partitioned by the fixed scroll (31) and the movable scroll (32). 1, the shaft support member 21 is provided with a suction passage 34 for sucking the suction fluid into the compression chamber 33. [

The movable scroll (32) is configured to revolve along with the rotation of the rotary shaft (14). A part of the rotary shaft 14 is protruded toward the compression portion 15 via the insertion hole 23 of the shaft supporting member 21. [ An eccentric shaft 35 is formed at an eccentric position with respect to the axis L of the rotary shaft 14 in the section of the rotary shaft 14 opposed to the compression section 15. A bush 36 is formed on the eccentric shaft 35. The bush 36 and the movable scroll 32 (more specifically, the movable base plate 32a) are connected via a bearing 37.

The motor-driven compressor 10 is provided with a rotation restricting portion 38 for restricting the rotation of the movable scroll 32 while allowing the revolving movement of the movable scroll 32. A plurality of rotation restricting portions 38 are formed.

According to this configuration, when the rotary shaft 14 rotates in the predetermined forward direction, the orbiting motion of the movable scroll 32 in the forward direction is performed. Specifically, the movable scroll 32 revolves in the forward direction around the axis of the fixed scroll 31 (i.e., the axis L of the rotary shaft 14). As a result, the volume of the compression chamber (33) decreases, so that the suction fluid sucked into the compression chamber (33) through the suction passage (34) is compressed. The compressed suction fluid, that is, the compressed fluid is discharged from the discharge port 41 formed in the fixed substrate 31a, and then discharged from the discharge port 11b. The forward direction is also referred to as a direction in which the compression of the fluid is normally performed.

1, a discharge valve 42 for covering the discharge port 41 is formed on the fixed substrate 31a. The compressed fluid compressed in the compression chamber (33) is discharged from the discharge port (41) by pushing down the discharge valve (42).

As shown in Figs. 1 and 2, an injection port 43 is formed in the fixed substrate 31a, separately from the discharge port 41. As shown in Fig. A plurality of injection ports 43 are formed, for example, two in detail. The injection port 43 is disposed radially outward of the discharge port 41 in the fixed substrate 31a. An injection pipe 119 is connected to the injection port 43. The connection destination of the injection pipe 119 will be described later.

The electric motor 16 rotates the rotary shaft 14 so that the movable scroll 32 revolves. As shown in Fig. 1, the electric motor 16 includes a rotor 51 that rotates integrally with the rotating shaft 14, and a stator 52 that surrounds the rotor 51. As shown in Fig. The rotor 51 is connected to the rotating shaft 14. A permanent magnet (not shown) is formed in the rotor 51. The stator 52 is fixed to the inner peripheral surface of the housing 11 (specifically, the first part 12). The stator 52 has a stator core 53 opposed to the normal rotor 51 in the radial direction and a coil 54 wound around the stator core 53.

The electric compressor (10) is provided with an inverter (55) as a drive circuit for driving the electric motor (16). The inverter 55 is accommodated in a housing 11, specifically a cylindrical cover member 56 mounted on a bottom portion 12b of the first part 12. The inverter 55 and the coil 54 are electrically connected.

Here, in the present embodiment, the electric compressor 10 is mounted on a vehicle and used in the vehicle air conditioning system 100. That is, in this embodiment, the fluid compressed by the electric compressor 10 is a refrigerant. The vehicle air conditioning system 100 will be described in detail below.

3, the vehicle air conditioning system 100 includes a pipe switching valve 101, a first heat exchanger 102, a second heat exchanger 103, a first expansion valve 104, a second expansion valve 104, (105) and a gas-liquid separator (106).

The pipe switching valve 101 has a plurality of inlets 101a to 101d. The pipe switching valve 101 is connected to the first state in which the first inlet 101a communicates with the second inlet 101b and the third inlet 101c and the fourth inlet 101d communicate with each other, The first inlet 101a and the third inlet 101c communicate with each other and the second inlet 101b and the fourth inlet 101d communicate with each other.

The vehicle air conditioning system 100 includes a first pipe 111 for connecting the first inlet 101a and the discharge port 11b of the motor compressor 10 and a second pipe 111 for connecting the second inlet 101b and the first heat exchanger 102, And a third pipe 113 connecting the first heat exchanger 102 and the first expansion valve 104. The second pipe 112 connects the first heat exchanger 102 and the first expansion valve 104 to each other. The vehicle air conditioning system 100 includes a fourth pipe 114 connecting the first expansion valve 104 and the gas-liquid separator 106, and a fourth pipe 114 connecting the gas-liquid separator 106 and the second expansion valve 105, A sixth pipe 116 connecting the second expansion valve 105 and the second heat exchanger 103 to the pipe 115 and a sixth pipe 116 connecting the second heat exchanger 103 and the third inlet 101c 7 pipe (117). The vehicle air conditioning system 100 further includes an eighth pipe 118 connecting the fourth inlet 101d and the inlet 11a of the motor-driven compressor 10.

In this configuration, the injection pipe 119 connected to the injection port 43 is connected to the gas-liquid separator 106. On the injection pipe 119, a check valve 120 is formed.

The vehicle air conditioning system 100 of the present embodiment is capable of both cooling operation and heating operation. Specifically, the vehicle air conditioning system 100 is provided with an air conditioning ECU 121 that controls the entire vehicle air conditioning system 100 including the pipe changeover valve 101. The air conditioning ECU 121 sets the pipe switching valve 101 to the first state, for example, during the cooling operation. In this case, the refrigerant discharged from the discharge port 11b flows into the first heat exchanger 102 and is condensed by heat exchange with the outside air in the first heat exchanger 102. [ The condensed refrigerant is decompressed in the first expansion valve 104 and flows to the gas-liquid separator 106. Then, it is separated into liquid and gas in the gas-liquid separator 106. The liquid refrigerant is depressurized by the second expansion valve 105 and flows to the second heat exchanger 103. Then, the liquid refrigerant is evaporated by heat exchange with the air in the car by the second heat exchanger 103, and as a result, the air in the car is cooled. The refrigerant evaporated in the second heat exchanger (103) flows toward the suction port (11a) of the electric compressor (10). During the cooling operation, the check valve 120 is in a closed state.

On the other hand, the air conditioning ECU 121 sets the pipe switching valve 101 to the second state, for example, during the heating operation. In this case, the refrigerant discharged from the discharge port 11b flows into the second heat exchanger 103 and is condensed by heat exchange with the air in the second heat exchanger 103. As a result, The air is heated. The refrigerant condensed in the second heat exchanger 103 is decompressed by the second expansion valve 105, flows into the gas-liquid separator 106, and is separated into liquid and gas in the gas-liquid separator 106. The refrigerant in the separated liquid is decompressed in the first expansion valve 104, flows in the first heat exchanger 102, and is evaporated by heat exchange with the outside air in the first heat exchanger 102. Then, the evaporated refrigerant flows into the suction port 11a.

Here, the check valve 120 is in the open state during the heating operation. Thereby, the refrigerant of the gas separated by the gas-liquid separator 106 flows into the compression chamber 33 through the injection pipe 119 and the injection port 43. This increases the flow rate of the refrigerant flowing into the compression chamber (33).

The pressure of the refrigerant of the gas separated by the gas-liquid separator 106, that is, the refrigerant introduced into the compression chamber 33 through the injection port 43 is higher than the pressure of the refrigerant sucked from the suction port 11a, Is lower than the pressure of the refrigerant discharged from the discharge port (11b). The refrigerant sucked from the suction port 11a is referred to as suction refrigerant and the refrigerant discharged from the discharge port 11b is referred to as compressed refrigerant and introduced into the compression chamber 33 from the injection port 43. In the following description, Is referred to as an intermediate-pressure refrigerant. The suction refrigerant corresponds to the "suction fluid", and the compressed refrigerant corresponds to the "compressed fluid".

In the vehicle air conditioner 100 configured as described above, the intermediate pressure refrigerant remains in the injection pipe 119 after the operation of the electric compressor 10 is stopped. The motor-driven compressor 10 of the present embodiment has a configuration for preferably discharging the intermediate-pressure refrigerant. This configuration will be described together with the electrical configuration of the coil 54 of the electric motor 16 and the inverter 55. Fig.

4, the coil 54 includes, for example, a u-phase coil 54u, a v-phase coil 54v, and a w- Phase structure having a phase coil 54w. That is, the electric motor 16 is a three-phase motor. Each of the phase coils 54u, 54v, and 54w is, for example, Y-connected.

The inverter 55 includes a u-phase and iv-phase arm switching element Qu1 and a u-phase and lower arm switching element Qu2 corresponding to the u-phase coil 54u. Similarly, the inverter 55 includes the v-phase and i -amp arm switching device Qv1 and the v-phase and lower arm switching device Qv2 corresponding to the v-phase coil 54v and the w-phase corresponding to the w-phase coil 54w And includes an ivory arm switching element Qw1 and a w-phase and a lower arm switching element Qw2. In short, the inverter 55 is a so-called three-phase inverter.

Each of the switching elements Qu1, Qu2, Qv1, Qv2, Qw1, Qw2 is composed of, for example, an IGBT. However, the present invention is not limited to this, and may be a power type MOSFET or the like.

The inverter 55 has two power lines EL1 and EL2 connected to a DC power supply E mounted on the vehicle. The inverter 55 further includes an u-phase wiring ELu connected to the positive power lines EL1 and EL2 and also having the two switching elements Qu1 and Qu2 on the u-phase. The positive switching elements Qu1 and Qu2 on the u-phase are connected in series to each other via the u-phase wiring ELu, and the connection portions of the switching elements Qu1 and Qu2 of the u- and a u-phase coil 54u are connected. The DC power source E is, for example, a storage device such as a battery or an electric double layer capacitor.

Similarly, the inverter 55 is provided with a v-phase wiring ELv connected to both power lines EL1, EL2 and also having both switching elements Qv1, Qv2 on the v-phase. the connection portion of the v-phase switching elements Qv1 and Qv2 in the v-phase wiring ELv is connected to the v-phase coil 54v. The inverter 55 is provided with a w-phase wiring ELw connected to both power lines EL1 and EL2 and further including w-phase switching elements Qw1 and Qw2. the connection portion of the w-phase switching elements Qw1 and Qw2 in the w-phase wiring ELw is connected to the w-phase coil 54w.

The inverter 55 also has a smoothing capacitor C1 connected in parallel to the DC power supply E. The inverter 55 also has reflux diodes Du1 to Dw2 connected in parallel to the switching elements Qu1 to Qw2. The reflux diodes Du1 to Dw2 may be parasitic diodes of the switching elements Qu1 to Qw2 or may be formed separately from the switching elements Qu1 to Qw2.

The motor-driven compressor 10 is provided with a control device 60 as a control unit for controlling the rotation of the rotor 51 by controlling the inverter 55 (more specifically, the switching operation of each of the switching devices Qu1 to Qw2) . The control device 60 is connected to the gates of the switching elements Qu1 to Qw2. The control device 60 can be realized by, for example, one or more dedicated hardware circuits and / or one or more processors (control circuits) operating in accordance with a computer program (software). The processor includes a CPU and a memory such as a RAM and a ROM, and the memory stores program codes or commands configured to cause the processor to execute the processing shown in Fig. 8, for example. The memory, or computer readable medium, includes all available media that can be accessed by a general purpose or dedicated computer.

The control device 60 performs PWM control of the inverter 55. [ Specifically, the control device 60 generates a control signal by using a carrier signal (carrier signal) and a command voltage value signal (comparison object signal). The control device 60 periodically applies a voltage having a predetermined pulse width DELTA T to each of the switching elements Qu1 to Qw2 using the generated control signal so that each of the switching elements Qu1 to Qw2 Is periodically turned on / off to convert the DC power from the DC power supply E into AC power. Then, the alternating-current power is input to the electric motor 16, whereby the electric motor 16 is driven, that is, rotated. In addition, the control device 60 is configured to be able to change the pulse width DELTA T of the switching elements Qu1 to Qw2, that is, the duty ratio of ON / OFF.

For reference, the control device 60 grasps the rotational position (rotational angle) of the rotor 51 that is at a standstill when the operation of the motor-driven compressor 10 is started, To Qw2, thereby rotating the rotor 51. [ That is, the rotor 51 needs to be stopped at the time of starting the motor-driven compressor 10. The specific configuration for grasping the rotational position of the rotor 51 is arbitrary.

The control device 60 is configured to be able to grasp the phase currents Iu, Iv, and Iw flowing in the phase coils 54u, 54v, and 54w as a current flowing in the electric motor 16. [ Specifically, as shown in Fig. 4, the inverter 55 is formed with current sensors 61 to 63 as current detecting portions for detecting the current flowing through the upper wirings (ELu to ELw). The current sensors 61 to 63 are formed between the lower arm switching elements Qu2 to Qw2 and the second power line EL2 in the upper wires ELu to ELw, for example. The current sensors 61 to 63 transmit the detection results to the control device 60. [ Based on the detection results of the current sensors 61 to 63, the control device 60 determines whether or not the u-phase current Iu, which is the current flowing in the u-phase coil 54u, The phase current Iv and the w-phase current Iw that is the current flowing in the w-phase coil 54w can be grasped.

The specific configuration of the current sensors 61 to 63 is arbitrary, but it is possible to consider, for example, a configuration having a shunt resistor and estimating the phase currents Iu to Iw from the voltage applied to the shunt resistor.

The control device 60 and the air conditioner ECU 121 are electrically connected, and information can be exchanged with each other. The control device 60 starts or stops the operation of the electric compressor 10 in accordance with a request from the air conditioning ECU 121, a result of the abnormality determination, or the like. The operation stop of the electric compressor 10 is to stop the supply of AC power to the electric motor 16 and more specifically to turn off all of the switching elements Qu1 to Qw2.

Here, the control device 60 of the present embodiment is configured such that, after a predetermined waiting period has elapsed after the operation of the motor-driven compressor 10 has been stopped, based on the detection results of the current sensors 61 to 63, And the rotational speed R, that is, the rotational speed of the vehicle. And the control device 60 that executes the holding process corresponds to the " holding portion ".

Specifically, the control device 60 keeps all the ivory arm switching elements Qu1, Qv1, and Qw1, which are the switching elements on the side not corresponding to the current sensors 61 to 63, in the OFF state. The control device 60 periodically turns ON / OFF the switching elements Qu2, Qv2, and Qw2, which are the switching elements on the side corresponding to the current sensors 61 to 63, with a predetermined switching pattern . In the present embodiment, each of the lower arm switching elements Qu2, Qv2 and Qw2 is subjected to a switching operation (that is, ON / OFF operation) and corresponds to a "three-phase target arm switching element".

For example, the control device 60 is a switching pattern in which the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON in a predetermined order in a predetermined order, and when the one- And controls the respective lower arm switching elements Qu2, Qv2 and Qw2 with a switching pattern (hereinafter referred to as a one-phase pattern) including an aspect in which the lower two arm phase switching elements are turned off. In the present embodiment, as shown in Figs. 5A to 5C, in the one-phase pattern, the lower arm switching element to be turned ON is switched from the u-phase lower arm switching element Qu2 to the v- And the switching element Qv2 is switched in the order of the w-phase upper and lower arm switching elements Qw2.

For example, a combination mode of Qu2: ON and also of Qu1, Qv1, Qw1, Qv2 and Qw2: OFF is referred to as a first mode, and a combination mode of Qv2: ON and also Qu1, Qv1, Qw1, Qu2, . In this case, the control device 60 may be switched from the first mode to the second mode by periodically turning on / off each of the lower arm switching devices Qu2, Qv2, and Qw2. In other words, the switching mode in the deceleration control (one-phase pattern) includes the first mode and the second mode in which ON / OFF combinations of the switching elements Qu1 to Qw2 are different.

The one-phase pattern is a switching pattern set so that no lower-arm switching elements of a plurality of phases (two-phase or three-phase) among the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned ON at the same time.

5A to 5C, the one-phase pattern is not limited to a switching pattern in which any one of the lower-arm switching elements is always in an ON-state, but all the lower-arm switching elements Qu2, Qv2, and Qw2 may be in the OFF state. For example, in the one-phase pattern, the lower arm switching elements are turned ON one by one in a predetermined order via the interval period, and when the one-phase lower arm switching element is ON, the other two- Or a switching pattern in which the device is in an OFF state.

Here, in the present embodiment, the timing at which each of the lower arm switching elements Qu2, Qv2, and Qw2 occurs in the ON state is different by a predetermined period? A. More specifically, during the period from the time when the lower arm switching device Qu2 occurs to the time when the lower arm switching device Qv2 occurs, and when the lower arm switching device Qw2 occurs from when the lower arm switching device Qv2 occurs And the period from when the lower arm switching element Qw2 takes place to when the lower arm switching element Qu2 occurs is the same predetermined period delta a. In this configuration, the one-phase pattern is a switching pattern in which the pulse width? T is set to be equal to or smaller than the predetermined period? A. When the pulse width DELTA T is less than the predetermined period delta a, the one-phase pattern is switched to the ON state by one phase in the predetermined order through the interval period (three-phase OFF period) . When the pulse width DELTA T is equal to the predetermined period DELTA a, the one-phase pattern becomes a switching pattern in which the lower-arm switching elements are turned ON one by one in a predetermined order without interposing an interval period.

Here, the relationship between the rotational direction and the number of rotations R of the rotor 51 and the phase currents Iu, Iv, and Iw will be described with reference to Figs. 6 and 7. Fig.

6 is a graph schematically showing the phase currents Iu, Iv and Iw detected when the rotor 51 rotates in the forward direction. Fig. 7 is a graph showing the relationship between the phase currents Iu, Iv and Iw when the rotor 51 rotates in the reverse direction (Iu, Iv, Iw) detected in the presence of the phase currents Iu, Iv, Iw. 6 and 7, the period of the minimum unit waveform (one triangular wave) of each of the phase currents Iu, Iv, and Iw is longer than the actual period.

6 and 7 show the current waveforms of the phase currents Iu, Iv and Iw when the lower arm switching elements Qu2, Qv2 and Qw2 are always turned on / off. Therefore, when each of the lower arm switching elements Qu2, Qv2 and Qw2 is actually switched in the one-phase pattern, the triangular wave signals Iu, Iv and Iw formed by the phase currents Iu, Iv and Iw shown in Figs. A triangular wave having a number of 1/3 of the number is obtained.

As shown in Figs. 6 and 7, the phase currents Iu, Iv, and Iw (specifically, the envelopes of the respective phase currents Iu, Iv, and Iw) have different phases from each other. For this reason, the phase current having a positive value transits sequentially with the lapse of time. The reason why the phase current becomes a positive value is that the back electromotive force generated in the phase coil corresponding to the phase current becomes lower than the back electromotive force generated in the other phase coil.

Here, the order in which the phase current to be a positive value transits is different between the case where the rotor 51 rotates in the forward direction and the case where the rotor 51 rotates in the reverse direction. Specifically, as shown in Fig. 6, when the rotor 51 is rotating in the forward direction, the phase current that becomes a positive value is the u-phase current Iu - > the v-phase current Iv- > ). On the other hand, as shown in Fig. 7, when the rotor 51 is rotating in the reverse direction, the phase current which becomes the positive value is the sum of the w-phase current Iw - > Transition in order.

The constant current period Ta in which the phase current becomes the positive value corresponds to 1/3 of one period of the electric angle of the rotor 51. [

The control device 60 calculates the current waveform based on the current waveforms obtained from the detection results of the respective current sensors 61 to 63 when the characteristics and the respective lower arm switching elements Qu2, Qv2 and Qw2 are switched in the one- , The rotational direction and the number of rotations (R) of the rotor (51).

In detail, when each of the lower arm switching elements Qu2, Qv2 and Qw2 switches in a one-phase pattern, the current waveforms of the respective phase currents Iu, Iv and Iw corresponding to the current rotational direction and the rotational speed R . The control device 60 grasps the transition order of the phase current that is a positive value from these current waveforms and determines whether the rotation direction of the rotor 51 is the forward direction or the reverse direction based on the detection result.

The control device 60 grasps the constant current period Ta from the current waveform obtained by the switching of the one-phase pattern and calculates the rotation number R of the rotor 51 based on the detected constant current period Ta .

For reference, these characteristics, specifically, the order in which the phase currents which are positive values are changed in accordance with the rotational direction and the points where the constant current period Ta corresponds to 1/3 of one period of the rotor 51 Do not vary according to the switching patterns of the respective lower arm switching elements Qu2, Qv2, Qw2. Therefore, even when the switching pattern of each of the lower arm switching elements Qu2, Qv2, Qw2 is a two-phase pattern, the control device 60 can obtain the above characteristics and the current waveforms obtained from the current sensors 61 to 63 The rotational direction and the number of rotations R of the rotor 51 can be grasped. Details of the two-phase pattern will be described later.

The control device 60 executes reverse rotation control processing for controlling the number of revolutions of the rotor 51 rotating in the reverse direction based on the determination that the rotor 51 is rotating in the reverse direction by the above holding processing do. This reverse rotation control processing will be described.

As shown in Fig. 8, the control device 60 first executes deceleration control for decelerating the number of rotations R to the target number of rotations Rt in step S101. The control device 60 that executes the process of step S101 corresponds to the " deceleration control section ".

The target rotation speed Rt is set to a predetermined allowable rotation speed Ra or less. More specifically, when the rotor 51 is rotating in the reverse direction, noise or vibration is generated from the motor-driven compressor 10. This noise or vibration tends to increase as the number of rotations R increases. In this respect, the allowable number of revolutions (Ra) is the maximum value at which noise or vibration is allowed.

The control device 60 sets at least one switching element among the switching elements Qu1 to Qw2 in the ON state in the deceleration control so that the rotor 51 is decelerated . In the present embodiment, in the deceleration control, the control device 60 periodically turns on / off each of the lower arm switching elements Qu2, Qv2, Qw2 with a predetermined switching pattern, thereby turning on the lower arm switching element And switches sequentially. That is, the switching control mode of the control device 60 in the deceleration control is such that the switching of the lower arm switching elements Qu2, Qv2, Qw2 to the ON / OFF switching states of the lower arm switching elements sequentially Operation). The reason that the lower arm switching elements to be turned ON sequentially is that the ON / OFF combination of the switching elements Qu1 to Qw2 (specifically, each of the lower arm switching elements Qu2, Qv2 and Qw2) It means change.

In this case, the switching frequencies of the lower arm switching elements Qu2, Qv2 and Qw2 are set equal to each other.

According to this configuration, when the phase current corresponding to the lower arm switching element in the ON state is fixed, heat is generated in the phase coil corresponding to the lower arm switching element in the ON state. Therefore, the kinetic energy of the rotor 51 is converted into thermal energy, and the rotor 51 decelerates. In the following description, the effect that the kinetic energy of the rotor 51 is converted into thermal energy and the rotor 51 is decelerated is referred to as a brake effect.

The phase currents and phase coils corresponding to the lower arm switching elements that are turned on mean that the u-phase current Iu and the u-phase coil 54u are in the ON state when the u-phase lower arm switching device Qu2 is in the ON state it means. Similarly, when the v-phase lower arm switching device Qv2 is in the ON state, it means the v-phase current Iv and the v-phase coil 54v, and when the w-phase lower arm switching device Qw2 is in the ON state w-phase current Iw and w-phase coil 54w.

In such a configuration, as the phase currents Iu, Iv, and Iw increase, heat is more likely to occur, so that the brake effect is enhanced. That is, as the phase currents Iu, Iv, and Iw increase, the force applied to the deceleration imparted to the rotor 51 tends to increase.

Further, the counter electromotive force generated in each of the phase coils 54u, 54v, and 54w increases as the rotation speed R increases. Then, the phase currents Iu, Iv, and Iw tend to increase as the counter electromotive force increases. In short, the phase currents Iu, Iv, and Iw depend on the number of rotations R. [

On the other hand, the control device 60 first starts the deceleration control by cyclically turning on / off each of the lower arm switching elements Qu2, Qv2, Qw2 with the predetermined initial deceleration duty ratio and the initial deceleration switching pattern. In the present embodiment, the initial switching pattern is a one-phase pattern. The initial deceleration duty ratio is set so that the phase current Iu flowing through the switching of the one-phase pattern when the rotational speed R is the maximum value of the rotational speed R assumed under the situation where the rotational speed R is reversely rotated by the intermediate- Iv, Iw) is set so as to correspond to the counter electromotive force which is generated when the allowable value and the rotation speed R are the assumed maximum values, so as not to exceed the predetermined allowable value. That is, the initial deceleration duty ratio and the initial switching pattern are set so that the phase currents Iu, Iv, and Iw do not exceed the allowable values irrespective of the number of rotations R of the rotor 51. The allowable value is, for example, a rated current value of each switching element (Qu1 to Qw2) or a value lower by a predetermined margin than the rated current value.

Thereafter, based on the detection results of the phase currents Iu, Iv, and Iw, the controller 60 sets the phase currents Iu, Iv, and Iw so that the phase currents Iu, Iv, At least one of the switching pattern and the ON / OFF duty ratio in the lower arm switching elements (Qu2, Qv2, Qw2) is variably controlled. For example, the control device 60 gradually increases the duty ratio from the initial deceleration duty ratio so that the phase currents Iu, Iv, and Iw do not exceed the allowable values.

Here, as described above, in the switching pattern of the present embodiment, the timings at which the respective lower arm switching elements Qu2, Qv2, Qw2 are turned ON differ from each other by a predetermined period? A. More specifically, during the period from the time when the lower arm switching device Qu2 occurs to the time when the lower arm switching device Qv2 occurs, and when the lower arm switching device Qw2 occurs from when the lower arm switching device Qv2 occurs And the period from when the lower arm switching element Qw2 takes place to when the lower arm switching element Qu2 occurs is the same predetermined period delta a. When the duty ratio is increased and the pulse width? T of each of the lower arm switching elements Qu2, Qv2 and Qw2 becomes longer than the predetermined period? A, the switching pattern is changed from the one-phase pattern to the two-phase pattern.

As shown in Figs. 9A to 9C, the two-phase pattern is a switching pattern in which the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are turned on in two-phases in a predetermined order, And the other one-arm low-side switching element is turned OFF when the low-arm switching element is in the ON state. For example, in the two-phase pattern, the lower arm switching element to be turned ON is the u-phase lower arm switching element Qu2 and the v-phase lower arm switching element Qv2 → the v-phase lower arm switching element Qv2 and w Upper and lower arm switching elements Qw2 → w upper and lower arm switching elements Qw2 and u upper and lower arm switching elements Qu2 → . In the two-phase pattern of the present embodiment, all of the ivory arm switching elements Qu1, Qv1, and Qw1 are maintained in the OFF state.

For example, a combination mode of Qu2, Qv2: ON and also of Qu1, Qv1, Qw1 and Qw2: OFF is referred to as a first mode and a combination mode of Qv2, Qw2: ON and Qu1, Qv1, . In this case, the control device 60 may be switched from the first mode to the second mode by periodically turning on / off each of the lower arm switching devices Qu2, Qv2, and Qw2. In other words, the switching manner in the deceleration control (two-phase pattern) includes the first aspect and the second aspect in which the ON / OFF combination of the switching elements Qu1 to Qw2 is different.

For reference, as shown in Figs. 9A to 9C, the two-phase pattern is not limited to a switching pattern in which any two-phase low-arm switching element is always in an ON state, and a two- And a one-phase ON period in which the two-phase low-arm switching element becomes the OFF state. For example, a two-phase pattern can be expressed by the following expression: Qu2: ON and Qv2: Qw2: OFF? Qu2, Qv2: ON Qw2: OFF? Qv2: ON Qu2, Qw2: OFF? Qv2, Qw2: : ON also Qu2, Qv2: OFF → Qu2, Qw2: ON and Qv2: OFF → ... May be a switching pattern. That is, the two-phase pattern may be a switching pattern in which the lower-arm switching elements are turned on in a predetermined order by two phases via a one-phase ON period (two-phase OFF period).

The two-phase pattern may include a three-phase ON period in which all the child-element switching elements Qu2, Qv2, and Qw2 are in an ON state. For example, the 2-phase pattern can be represented as: Qu2, Qv2: ON, Qw2: OFF? Qu2, Qv2, Qw2: ON? Qv2, Qw2: ON, Qv2: OFF → Qu2, Qv2, Qw2: ON → Qu2, Qv2: ON and Qw2: OFF → ... May be a switching pattern. That is, the two-phase pattern may be a switching pattern in which the lower-arm switching elements are turned on in the predetermined order by two phases via the three-phase ON period.

When the pulse width DELTA T of each of the lower arm switching elements Qu2, Qv2 and Qw2 is shorter than twice the predetermined period delta a, the two-phase pattern is switched by the one- The switching pattern becomes an ON state in which the elements are turned on for two phases in a predetermined order. When the pulse width? T is longer than twice the predetermined period? A, the two-phase pattern is a switching pattern in which the lower-arm switching elements are turned ON by two phases in a predetermined order, . When the pulse width? T is equal to twice the predetermined period? A, the two-phase pattern does not include the one-phase ON period and the three-phase ON period, and the lower arm switching elements are arranged in two- The switching pattern becomes the ON state. The higher the duty ratio, the higher the braking effect is.

Here, in the configuration in which the switching of the lower arm switching elements Qu2, Qv2, Qw2 is performed in the two-phase pattern, there is an aspect in which the two-phase lower arm switching elements are simultaneously turned on. The lower arm switching element corresponding to the phase current which becomes the positive value can be turned ON by the frequency twice during the switching of the conference. Therefore, the two-phase pattern is a switching pattern in which the phase currents Iu, Iv, and Iw tend to be higher than the one-phase patterns.

Then, after the switching pattern is switched from the one-phase pattern to the two-phase pattern, the control device 60 further gradually increases the duty ratio within a range in which the phase currents Iu, Iv, and Iw do not exceed the allowable values .

Since the phase currents Iu, Iv, and Iw depend on the number of rotations R, the phase currents Iu, Iv, and Iv are set so that, when decelerating the rotation speed R gradually, The actual phase currents Iu, Iv, and Iw do not always increase even when the switching pattern and the duty ratio are variably controlled so as to be gradually increased. That is to say, the variable control of the switching pattern and the duty ratio, in which the phase currents Iu, Iv and Iw are likely to gradually increase, does not mean that the phase currents Iu, Iv and Iw actually need to be increased, (Iu, Iv, Iw) can be suppressed.

The control device 60 also grasps the number of rotations R of the current rotor 51 from the waveforms of the phase currents Iu, Iv and Iw obtained by the deceleration control. The control device 60 then continues the deceleration control until the rotational speed R becomes the target rotational speed Rt and the control device 60 continues the deceleration control until the rotational speed R becomes the target rotational speed Rt The deceleration control is terminated. The timing at which the execution start timing of the process at step S101 corresponds to the timing at which the deceleration control starts and the timing at which the number of rotations R becomes the target number of rotations Rt corresponds to the timing at which the deceleration control ends. Further, the control device 60 stores the first period T1 which is the execution period of the deceleration control. In addition, the first period T1 varies depending on the state at the time of stopping the operation.

8, when the number of rotations R has decelerated to the target number of rotations Rt, the control device 60 advances to step S102 to execute continuation control to continue the reverse rotation of the rotor 51 . The control device 60 that executes the process of step S102 corresponds to the " continuation control section ".

The control device 60 controls the inverter 55 so that the rotation speed R is maintained at the target rotation speed Rt in the continuous control. Specifically, the control device 60 periodically turns ON / OFF the respective low arm switching elements Qu2, Qv2, Qw2 with a predetermined initial continuation switching pattern and initial continuation duty ratio to start the continuous control. In the present embodiment, the initial continuation switching pattern and the initial continuation duty ratio are the switching pattern and the duty ratio set at the end of deceleration control.

Here, during the reverse rotation of the rotor 51, the intermediate-pressure refrigerant is discharged. When the intermediate-pressure refrigerant is discharged, the pressure of the intermediate-pressure refrigerant in the injection pipe 119 is lowered, so that the kinetic energy for reversing the rotation of the rotor 51 is reduced. Therefore, if the switching control of the same mode continues, the rotational speed R gradually decreases due to the reduction of the kinetic energy accompanying the reverse rotation of the rotor 51.

On the other hand, in the present embodiment, the control device 60 variably controls at least one of the switching pattern and the duty ratio (both in this embodiment) so that the phase currents Iu, Iv, and Iw are gradually lowered. Specifically, the control device 60 gradually decreases the duty ratio so that the rotation speed R is maintained at the target rotation speed Rt. Further, when the duty ratio reaches the lower limit value corresponding to the two-phase pattern in a situation where the switching pattern is a two-phase pattern, the control device 60 switches the switching pattern to the one-phase pattern and gradually decreases the duty ratio .

According to such a configuration, the thermal energy consumed by the electric motor 16 is reduced in response to the reduction of the kinetic energy accompanying the discharge of the intermediate-pressure refrigerant, so that the rotational speed R is reduced to the target rotational speed Rt It becomes easier to maintain.

The control device 60 also grasps the current number of rotations R from the waveforms of the respective phase currents Iu, Iv and Iw obtained by the continuous control, The feedback control of the switching pattern and the duty ratio is carried out so as to approach the target value Rt. That is, the controller 60 sets the phase current Iu (Iu) in correspondence with the pressure change of the intermediate-pressure refrigerant in the injection pipe 119 so that the revolution number R approaches the target revolution number Rt during the continuous control , Iv, and Iw.

The control device 60 executes the continuous control over the second period T2 that is longer than the first period T1 that is the execution period of the deceleration control. Specifically, the control device 60 periodically determines whether or not a predetermined continuation control termination condition is established during continuation control. The continuation control termination condition is set so that, for example, (A) the execution period of the continuous control (i.e., the second period T2) is longer than the first period T1, Is equal to or smaller than a predetermined end gauge current value.

Here, the termination current value is set to correspond to a state in which the intermediate-pressure refrigerant remaining in the injection pipe 119 is fully discharged, that is, a state in which the rotor 51 does not move after stopping due to the intermediate-pressure refrigerant . Specifically, the control device 60 is provided with map data in which aspects of the switching control (specifically, the switching pattern and the duty ratio) and the termination current value are associated with each other. The finalized gauge current value is a value obtained by subtracting the phase current Iu when the pressure of the intermediate-pressure refrigerant remaining in the injection pipe 119 is a predetermined allowable pressure value in a state in which the switching control corresponding to the termination- Iv, Iw).

The control device 60 refers to the map data to grasp the ending instrument current value corresponding to the mode of the current switching control and judges whether or not each phase current Iu, Iv, Iw flowing by the switching control corresponds to the end instrumentation current value Or less. When the phase currents Iu, Iv, and Iw are equal to or lower than the termination current value, the control device 60 determines that the condition (B) is satisfied.

The control device 60 continues execution of the control continuously until the continuation control termination condition is established.

When the continuation control termination condition is satisfied, the control device 60 proceeds to step S103 to execute stop control to stop the rotor 51. [ Specifically, the control device 60 holds all the lower arm switching elements Qu2, Qv2, and Qw2 in the ON state. That is, the control device 60 short-circuits all the phase coils 54u, 54v, and 54w. Also, the stop control may be referred to as deceleration control in which the three-phase low-arm switching elements Qu2, Qv2 and Qw2 are all set to the ON state and the duty ratio is set to 100%.

Next, the operation of the present embodiment will be described with reference to Fig. Fig. 10 is a graph schematically showing the change of the rotation speed R after the operation is stopped. In Fig. 10, the rotation in the forward direction is referred to as " + " and the rotation in the reverse direction is referred to as " - ".

As shown in Fig. 10, when the operation of the electric compressor 10 is stopped at the timing t1, the rotational speed R of the rotor 51 gradually decreases. Then, at the timing t2, the rotation direction of the rotor 51 changes from the forward direction to the reverse direction. Thereafter, the rotational speed R becomes higher than the target rotational speed Rt and becomes higher than the allowable rotational speed Ra.

At the timing t3, the grasp process is executed, and when it is recognized that the rotor 51 is rotating in the reverse direction, the deceleration control is started. Thereby, the conversion from kinetic energy to thermal energy is performed, and the rotor 51 starts to decelerate. In this case, as described above, the braking effect gradually becomes stronger, so that the deceleration of the rotation speed R gradually increases.

Thereafter, when the number of rotations R reaches the target number of rotations Rt at the timing t4, deceleration control is switched to continuous control. In this case, the first period T1 is the timing from t3 to t4. The difference between the rotation speed R at the timing t3 of the deceleration control start timing and the rotation speed R at the timing t4 which is the end timing of the deceleration control is the deceleration rotation speed difference ) < / RTI >

Here, during the continuous control, the rotation speed R is maintained at the target rotation speed Rt. In this case, actually, the number of rotations R does not completely coincide with the target number of rotations Rt, but fluctuates somewhat. However, the continuous rotation speed difference (continuous rotation speed difference)? R2 that is the difference between the minimum value and the maximum value of the number of rotations R during the continuous control is sufficiently smaller than the reduced rotation speed difference? R1. The continuous rotation number difference DELTA R2 corresponds to the variation in the number of rotations R of the rotor 51 during continuous control.

When the continuous control end condition is satisfied at the timing t5, the switching control is switched from the continuous control to the stop control, and the reverse rotation of the rotor 51 is stopped at the timing t6. In this case, the second period T2 is the timing from t4 to t5.

According to the present embodiment described in detail above, the following effects are exhibited.

(1) The electric compressor 10 includes an electric motor 16 having a rotor 51, a housing 11 having a suction port 11a through which a refrigerant as a fluid is sucked, And a compression section (15) for discharging the compressed refrigerant. The compression section 15 includes a fixed scroll 31 fixed to the housing 11, a movable scroll 32 which is meshed with the fixed scroll 31 and capable of orbital motion with respect to the fixed scroll 31, And a compression chamber (33) partitioned by a scroll (31) and a movable scroll (32). The compression section 15 is configured to compress the suction refrigerant sucked into the compression chamber 33 by the idle movement of the movable scroll 32 in the forward direction when the rotor 51 rotates in the normal direction.

In this configuration, the motor-driven compressor 10 includes an injection port 43 for introducing an intermediate-pressure refrigerant, which is higher in pressure than the suction refrigerant and lower in pressure than the compressed refrigerant, into the compression chamber 33, And a control device 60 for controlling the rotation of the rotor 51 by controlling the inverter 55. [ The control device 60 executes deceleration control for decelerating the rotor 51 over the first period T1 in response to the rotor 51 being rotated in the direction opposite to the normal direction. The control device 60 then performs continuation control to continue the reverse rotation of the rotor 51 over the second period T2 longer than the first period T1 after the end of the deceleration control. (Continuous rotation speed difference) DELTA R2 that is the difference between the maximum value and the minimum value of the number of revolutions (rotation speed) R of the rotor 51 under the continuous control is the number of revolutions of the deceleration control start timing R (Deceleration rotational speed difference) DELTA R1, which is the difference between the number of revolutions of the deceleration control and the number of revolutions R of the end timing of the deceleration control.

According to such a configuration, when the rotor 51 is reversely rotated, the rotor 51 is decelerated during the first period T1, and thereafter, the rotor 51 is rotated in the second period T1 longer than the first period T1. Over the period T2, the reverse rotation of the rotor 51 is continued at a relatively low number of rotations R. [ Thereby, it is possible to discharge the intermediate-pressure refrigerant while suppressing noise or vibration.

In more detail, noise and vibration are likely to increase as the number of rotations R increases. Therefore, if the state in which the number of rotations R is high continues for a long time, noise and vibration are prone to be disturbed. However, if the rotor 51 is forcibly stopped early, the intermediate-pressure refrigerant remains in the injection pipe 119. Then, after the rotation of the rotor 51 is stopped, a re-rotation phenomenon in which the rotor 51 is rotated in the reverse direction again may occur. The rotational position of the rotor 51 is shifted. Therefore, the starting of the motor-driven compressor 10, which controls each of the switching elements Qu1 to Qw2 based on the rotational position of the rotor 51, It may cause trouble.

On the other hand, in the present embodiment, deceleration control is performed first, and continuous control is performed after the number of rotations R is lowered. Since the continuous control is a control in which the fluctuation of the number of rotations R is smaller than the deceleration control, the reverse rotation of the rotor 51 is likely to be maintained at a relatively low number of rotations R in continuous control. Thereby, it is possible to suppress noise and vibration during continuous control. Then, the continuous control is performed over the second period T2 longer than the first period T1, whereby the intermediate-pressure refrigerant can be preferably discharged. Since the first period T1, which is the execution period of the deceleration control with a relatively high number of revolutions R, is shorter than the second period T2, noise and vibration are not taken care of. From the above, it is possible to suppress the generation of the re-rotation phenomenon while suppressing noise and vibration. Therefore, it is possible to suppress the problem that trouble occurs in starting the electric compressor 10 due to the intermediate-pressure refrigerant.

(2) In the deceleration control, the control device 60 controls the rotor 51 until the rotational speed R of the rotor 51 reaches the target rotational speed Rt set to a predetermined allowable rotational speed Ra or less, . The control device 60 causes the rotor 51 to continue to rotate in a state where the number of rotations R is equal to or less than the allowable number of rotations Ra during the second period T2. According to such a configuration, since the number of rotations R is equal to or less than the allowable number of rotations Ra during continuous control, noise and vibration can be more preferably suppressed.

(3) The control device 60 controls the inverter 55 so that the rotation speed R is maintained at the target rotation speed Rt in the continuous control. According to such a configuration, since the state in which the rotation speed R is high is maintained as compared with the configuration in which the rotation speed R gradually decreases from the target rotation speed Rt, the intermediate-pressure refrigerant is liable to be discharged. As a result, the intermediate-pressure refrigerant can be quickly discharged. Therefore, the second period T2 can be shortened, and the period until the rotor 51 stops can be shortened.

(4) The inverter 55 has the ivory arm switching elements Qu1, Qv1, Qw1 and the lower arm switching elements Qu2, Qv2, Qw2 which are connected to each other in the same manner. The control device 60 controls each of the switching elements Qu1 to Qw2. The control device 60 keeps each of the ivory arm switching elements Qu1, Qv1 and Qw1 in the OFF state and also turns the respective lower arm switching elements Qu2, Qv2 and Qw2 periodically ON / OFF Thereby sequentially switching the lower arm switching elements to be in the ON state.

According to such a configuration, the phase current corresponding to the lower arm switching element to be turned ON flows, so that the kinetic energy of the rotor 51 is converted into thermal energy. Thereby, the rotor 51 can be decelerated.

Here, it is also conceivable that the lower arm switching elements Qu2, Qv2, Qw2 are kept in the ON state without periodically turning them on and off. However, when the ON state of each of the lower arm switching elements Qu2, Qv2, and Qw2 is maintained, each of the phase currents Iu, Iv, and Iw becomes excessively high, possibly exceeding the allowable value. On the other hand, in the present embodiment, since the configuration in which the lower arm switching elements Qu2, Qv2, Qw2 are periodically turned on / off is employed, it is possible to suppress the phase currents Iu, Iv, Iw from becoming excessively high can do.

In the present embodiment, the phase currents Iu, Iv, and Iw are equal to each other because the lower arm switching elements to be turned on are sequentially changed. As a result, the phase current per phase for obtaining the desired brake effect can be reduced. Therefore, it is possible to suppress excessive increase in the phase currents Iu, Iv, and Iw for decelerating the rotor 51. [ Therefore, it is possible to reduce the rotation speed of the rotor 51 at an early stage while suppressing the occurrence of a trouble in the operation of the inverter 55 owing to the fact that the electric current flowing through the electric motor 16 becomes excessively high, Vibration can be suppressed.

Further, since the lower arm switching elements which are in the ON state are sequentially changed, it is possible to suppress the variation in the calorific value of the three lower arm switching elements Qu2, Qv2, Qw2. As a result, it is possible to suppress the phenomenon that only a specific lower arm switching element among the three subsidiary arm switching elements Qu2, Qv2 and Qw2 excessively generates heat. Therefore, the rotor 51 can be decelerated while suppressing local heat generation of a specific lower arm switching element.

(5) In particular, the brake effect is caused by the ON / OFF state of the lower arm switching element corresponding to the phase current which becomes the positive value. Then, the lower arm switching elements, to which a phase current that is a positive value can flow, are sequentially changed in a predetermined order. For this reason, in a configuration in which only one predetermined upper and lower arm switching elements are periodically turned ON / OFF, deceleration is performed only during a period in which the phase current corresponding to the predetermined phase is a positive value. In this case, intermittent deceleration is applied to the rotor 51, for example, a sufficient brake effect can not be obtained, or a problem that the reverse rotation of the rotor 51 becomes unstable may occur.

On the other hand, in the present embodiment, since the low-arm switching elements to be turned on are sequentially changed, the phase of the phase current corresponding to the phase current which is a positive value at a predetermined frequency (at least three times in this embodiment) The arm switching element can be turned ON. Thereby, since the deceleration can be continuously performed, the above problem can be suppressed.

It is also conceivable to grasp the constant current period Ta of each of the phase currents Iu, Iv and Iw in advance and control to periodically turn ON / OFF only the upper and lower arm switching elements corresponding to the constant current period Ta . However, in order to perform the control, it is necessary to grasp the rotational position of the rotor 51 and to synchronize the switching of the rotational positions with the switching of the lower arm switching elements Qu2, Qv2, Qw2. In this case, a rotation angle sensor such as a resolver is separately required or complicated control is required, which complicates the configuration.

On the contrary, in the present embodiment, since the lower arm switching elements to be in the ON state are sequentially changed as described above, the rotational position of the rotor 51 can be grasped, and the rotational position of the lower arm switching elements Qu2, Qv2 , Qw2 of the rotor 51 can be decelerated without switching. Therefore, the complexity of the configuration can be suppressed.

(6) The control device 60 starts the deceleration control by cyclically turning ON / OFF the respective low arm switching elements Qu2, Qv2, Qw2 with a predetermined initial deceleration switching pattern and the initial deceleration duty ratio. Thereafter, the controller 60 sets the switching pattern and the duty ratio of each of the lower arm switching elements Qu2, Qv2, and Qw2 so that the phase currents Iu, Iv, and Iw are increased within a range not exceeding the allowable value And at least one of them is variably controlled. With this configuration, it is possible to reduce the rotational speed R of the rotor 51 relatively early, while suppressing excessive increase in the phase currents Iu, Iv, Iw at the start of the deceleration control.

In detail, each of the phase currents Iu, Iv, and Iw tends to increase as the number of rotations R of the rotor 51 increases. Therefore, when the switching pattern and the duty ratio, in which the phase currents Iu, Iv, Iw tend to be high, are set from the beginning of the deceleration control in which the rotation speed R is high, the phase currents Iu, Iv, Is likely to become excessively high. However, if the deceleration control is continued with the switching pattern and the duty ratio, in which the phase currents Iu, Iv, and Iw tend to decrease, the rotational speed R of the rotor 51 does not drop well.

On the other hand, in the present embodiment, after the deceleration control is started with the initial deceleration switching pattern and the initial deceleration duty ratio, each of the lower arm switching elements (Iu, Iv, Iw) Qu2, Qv2, and Qw2 are controlled. This makes it possible to shorten the first period T1 by increasing the brake effect while suppressing excessive increase in the phase currents Iu, Iv, Iw at the start of the deceleration control.

(7) The control device 60 starts the continuous control by cyclically turning ON / OFF the respective low arm switching elements Qu2, Qv2, Qw2 with the initial continuation switching pattern and the initial continuation duty ratio. Thereafter, the control device 60 variably controls at least one of the switching pattern and the duty ratio of each of the lower arm switching elements Qu2, Qv2, and Qw2 so that the phase currents Iu, Iv, and Iw are gradually lowered. According to such a configuration, after starting the continuous control, the thermal energy consumed by the electric motor 16 is gradually reduced. Thereby, even if the kinetic energy is gradually lowered due to the pressure drop from the injection port 43 accompanying the discharge of the intermediate-pressure refrigerant during the continuous control, the rotation speed R can be maintained to some extent. Therefore, it is possible to suppress the continuation number of revolutions difference? R2 from becoming larger than the reduced rotation number difference? R1.

(8) The control device 60 performs stop control for stopping the rotation of the rotor 51 after completion of the continuation control. According to this configuration, it is possible to stop the rotation of the rotor 51 at an early stage in comparison with a configuration in which the motor is decelerated naturally after the continuous control ends. This makes it possible to shorten the period from when the deceleration control is started to when the reverse rotation of the rotor 51 is stopped.

(9) The control device 60 grasps the rotational direction and the number of rotations R of the rotor 51 based on the phase currents Iu, Iv, and Iw flowing through deceleration control and continuation control. According to this configuration, since the rotation direction and the rotation number R of the rotor 51 can be grasped without forming a dedicated sensor or the like, sensorlessization can be achieved. The rotation direction and the rotation number R of the rotor 51 are grasped based on the phase currents Iu, Iv and Iw flowing by the deceleration control and the continuation control so that the effective use of the deceleration control and the continuation control . In other words, it is possible to simplify the control by the amount of current control that is not required to be carried out in order to grasp the rotational direction and the number of rotations R of the rotor 51.

The above embodiment may be modified as follows.

The continuation control is not limited to the control for keeping the number of rotations R at the target number of rotations Rt. For example, the continuous control may be such that the rotation speed R gradually decreases within a range in which the continuous rotation speed difference? R 2 is smaller than the reduced rotation speed difference? R 1.

The control device 60 may control the lower arm switching elements Qu2, Qv2, and Qw2 such that the rotational speed R is increased within the allowable rotational speed Ra during continuous control. Further, the control device 60 may alternately repeat acceleration and deceleration. The point is that the continuous control is carried out when the continuous rotation number difference DELTA R2 is smaller than the reduced rotation speed difference DELTA R1 and longer than the first period T1, The specific variation of the embodiment is arbitrary. The difference between the rotation speed R at the start timing of deceleration control and the rotation speed R at the end timing of deceleration control may be employed as the continuous rotation number difference DELTA R2.

The specific switching control modes of the deceleration control and the continuation control are not limited to those of the embodiment, but may be arbitrary. For example, the control device 60 may be configured to periodically turn ON / OFF only a predetermined fixed-phase lower-arm switching element, and to keep the lower-arm switching elements of other phases OFF. The control device 60 may be configured to periodically turn ON / OFF the synchronizing timing of the rising and falling timing of the three-phase lower arm switching devices Qu2, Qv2, Qw2.

The control device 60 may employ a switching pattern and a duty ratio that tend to increase the phase currents Iu, Iv, and Iw as the rotational speed R is lowered in the deceleration control, Are arbitrary.

Control device 60 may not change the switching pattern and the duty ratio from the initial deceleration switching pattern and the initial deceleration duty ratio during deceleration control. Similarly, the control device 60 may be configured so as not to change the switching pattern and the duty ratio from the initial continuation switching pattern and the initial continuation duty ratio during the continuous control.

The initial continuous switching pattern and initial sustained duty ratio are not limited to the switching pattern and the duty ratio at the end timing of the deceleration control but may be arbitrary unless the number of rotations R fluctuates excessively.

The target rotation speed Rt that is the ending point of the deceleration control may be different from the target rotation speed Rt that is maintained in the continuous control. For example, the control device 60 executes the deceleration control until the rotation speed R becomes the first target rotation speed, and then the rotation speed R is lower than the first target rotation speed by the second target rotation speed The rotation of the rotor 51 in the reverse direction may be continued. In this case, the second target rotational speed is preferably equal to or less than the allowable rotational speed Ra. The first target rotational speed may be equal to or less than the allowable rotational speed Ra or may be slightly higher than the allowable rotational speed Ra.

○ Stop control may be omitted. In this case, the rotor 51 stops due to natural deceleration.

The termination condition of the deceleration control is not limited to the case where the number of rotations R reaches the target number of rotations Rt. For example, the termination condition of the deceleration control may be one in which a predetermined first period (T1) has elapsed from the start timing of the deceleration control.

The condition (B) of the continuation control termination condition may be omitted. In this case, the second period T2 may be set to a period during which the intermediate-pressure refrigerant can be sufficiently discharged, for example, regardless of the state at the time of stopping the operation.

In the case where the condition (B) is omitted, the second period T2 may be set in correspondence with the first period T1. For example, the second period T2 may be set longer as the first period T1 is shorter. Thus, when the discharge amount of the intermediate-pressure refrigerant during the deceleration control is small due to the first period (T1) being short, the discharge amount of the intermediate-pressure refrigerant under continuous control can be increased. Therefore, the intermediate-pressure refrigerant can be desirably discharged.

In the embodiment, the three-phase target arm switching elements to be subjected to the switching operation are the respective lower arm switching elements Qu2, Qv2 and Qw2, but the present invention is not limited to this. For example, each of the ivory arm switching elements Qu1, Qv1, It may be. Specifically, the control device 60 may periodically turn on / off each of the ivory arm switching devices Qu1, Qv1, and Qw1 so that the ivory arm switching elements to be turned on are sequentially changed. In this case, it is preferable that each of the lower arm switching elements Qu2, Qv2, Qw2 is kept in the OFF state, for example. It is also preferable that the current sensors 61 to 63 are formed between the ivory arm switching elements Qu1 to Qw1 and the first power line EL1 in the upper wirings ELu to ELw.

That is, the switching control mode of the control device 60 in the deceleration control may be such that each of the ivory arm switching elements Qu1, Qv1, Qw1 is switched to operate so that the ivory arm switching elements to be turned on are sequentially switched .

The controller 60 also performs switching operation (that is, periodically ON / OFF) of each of the ivory arm switching elements Qu1, Qv1, Qw1 and each of the lower arm switching elements Qu2, Qv2, Qw2 do. That is, the three-phase target arm switching device to be a switching operation may be both of the three-phase ivory arm switching devices Qu1, Qv1, Qw1 and the three-phase lower arm switching devices Qu2, Qv2, Qw2. In this case, it is preferable that the control device 60 controls so that the ivory arm switching element and the lower arm switching element of the same phase are not turned on at the same time. More specifically, the switching control mode of the control device 60 is such that the ivory arm switching elements that are turned on are sequentially switched so that the ivory arm switching element and the lower arm switching element of the same phase are not simultaneously turned on, It may be an aspect of sequentially switching the lower arm switching elements to be in the ON state.

That is, in the deceleration control, the control device 60 turns on at least one of the three-phase armature switching elements Qu1, Qv1, Qw1 and the three armature switching elements Qu2, Qv2, Qw2 of three phases So that the rotor 51 is decelerated. In this case, the switching control mode of the control device 60 in the deceleration control is such that one or a plurality of switching elements of all the switching elements Qu1 to Qw2 are turned on and the other switching elements are turned off And the combination of the switching element to be in the ON state and the switching element to be in the OFF state includes the second aspect which is different from the first aspect. Thereby, it is possible to suppress a situation in which only a specific switching element generates heat locally, and thereby the rotor 51 can be preferably decelerated.

In the second aspect, a combination of the ON / OFF states of the switching elements Qu1 to Qw2 may be different from the first aspect, and a part of the switching elements in the ON state may overlap with the first aspect. For example, in the two-phase pattern, an aspect of Qu2, Qv2: ON, and Qu1, Qv1, Qw1 and Qw2: OFF is referred to as a first mode, and Qv2, Qw2: ON and Qu1, Qv1, Qw1, It is called the second aspect. In this case, the v-phase and lower-arm switching device Qv2 is in the ON state in both the first and second aspects. On the other hand, in the first embodiment, the u-phase lower arm switching device Qu2 is turned ON and the w-phase lower arm switching device Qw2 is turned ON in the second mode. Therefore, in the first and second aspects, , The switching elements in the ON state are different.

The controller 60 may be configured to variably control either the switching pattern or the duty ratio. For example, the control device 60 may be configured to fix the switching pattern to either a one-phase pattern or a two-phase pattern, to control the duty ratio only or to vary the duty ratio, It may be switched to an image pattern. In essence, the control device 60 may be capable of variably controlling at least one of the switching pattern and the duty ratio in accordance with the number of rotations R.

The order of the lower arm switching elements to be turned ON in the one-phase pattern is arbitrary. For example, in the one-phase pattern, the lower arm switching element to be in the ON state is composed of the w-phase lower arm switching element Qw2 → v-phase lower arm switching element Qv2 → u-phase lower arm switching element Qu2 . The same applies to the two-phase pattern.

In the two-phase pattern, combinations of phases that are in the ON state at any time are arbitrary.

The switching pattern is arbitrary as long as the target arm switching element to be turned ON is sequentially changed. For example, the switching pattern may be an aspect in which the target arm switching elements are turned ON by one by one in a predetermined order through a three-phase ON period in which all the three-phase target arm switching elements are in the ON state.

In the two-phase pattern described in the embodiment, the timings at which the respective lower arm switching elements Qu2, Qv2, and Qw2 occur in the ON state are shifted, but the present invention is not limited to this. For example, the two-phase pattern may be a switching pattern in which the timing of the two-phase low-arm switching element to occur in the ON state coincides with each other. For example, the two-phase pattern can be expressed as follows: Qu2, Qv2: ON, Qw2: OFF? Qu2, Qv2, Qw2: OFF? Qv2, Qw2: Qv2: OFF? Qu2, Qv2, Qw2: OFF? Qu2, Qv2: ON and Qw2: OFF? May be a switching pattern. That is, the two-phase pattern may be a switching pattern in which the target arm switching elements are turned on for every two phases in a predetermined order via an interval period in which all of the three-phase target arm switching elements are in the OFF state. In other words, the two-phase pattern includes a switching pattern including an interval period, a switching pattern including a one-phase ON period, a switching pattern including a three-phase ON period, and a switching period including an interval period, At least one of the switching patterns not including any period of the period is included.

Further, in the embodiment, since the timing at which each of the lower arm switching elements Qu2, Qv2 and Qw2 is turned ON is shifted, the switching pattern is changed to a one-phase pattern or a two-phase pattern by adjusting the duty ratio. However, as described above, even when two of the lower arm switching elements Qu2, Qv2 and Qw2 are ON at the same timing (that is, when there is no phase shift), the switching pattern does not change even if the duty ratio is adjusted . That is, the duty ratio and the switching pattern may or may not be related to each other.

The specific configuration of the control device 60 for grasping the rotational direction and the rotational speed R of the rotor 51 is arbitrary, and for example, a rotational angle sensor such as a resolver is formed, and the detection result of the rotational angle sensor Or the like.

When the predetermined condition is satisfied, for example, the control device 60 determines that the rotational direction of the rotor 51 detected by the holding process is reverse and the rotational speed R detected by the holding process is At least one of the deceleration control and the continuation control may not be performed if the difference is equal to or smaller than a predetermined threshold value. That is, the control device 60 is not limited to the configuration in which the deceleration control and the continuous control are always performed after the operation stop of the motor-driven compressor 10 (that is, the reverse rotation of the rotor 51) (For example, when the reverse rotation speed R is higher than the threshold value), the deceleration control and the continuation control may be executed. In essence, the control device 60 may have a function of performing deceleration control and a function of performing continuous control.

The threshold value may be any value as long as it is a comparatively low value, but may be a value lower than the target rotation speed Rt or may be a value higher than the target rotation speed Rt and lower than the allowable rotation speed Ra . The threshold value may be, for example, an allowable revolution speed (Ra).

The position and the number of the injection port 43 are arbitrary.

The object to which the electric compressor 10 is to be mounted is not limited to the vehicle, but may be arbitrary.

Although the electric compressor 10 is used in the vehicle air conditioning system 100, the electric compressor 10 is not limited to this, and may be used in other devices. For example, when the vehicle is a fuel cell vehicle (FCV) equipped with a fuel cell, the electric compressor 10 may be used for a supply device for supplying air to the fuel cell. In essence, the fluid to be compressed is arbitrary, and may be a refrigerant or air.

The embodiments and the separate examples may be appropriately combined. For example, the control device 60 performs the switching operation of the three-phase armature switching elements Qu1, Qv1, and Qw1 so that the ivory arm switching elements to be turned on are sequentially changed, The switching operation of the three-phase lower arm switching devices Qu2, Qv2, and Qw2 may be performed so that the lower-arm switching devices sequentially change. For example, the control device 60 performs a switching operation on the three-phase upper arm switching elements Qu1, Qv1, Qw1 or the three-phase lower arm switching elements Qu2, Qv2, Qw2, The switching operation may be performed on the elements Qu1 to Qw2.

Claims (9)

An electric motor having a rotor,
A housing having a suction port through which fluid is sucked,
A compression unit that is driven by the electric motor and compresses the suction fluid that is the fluid sucked from the suction port and discharges the compressed fluid that is the compressed suction fluid;
A drive circuit for driving the electric motor;
And a control section for controlling the rotation of the rotor by controlling the drive circuit,
Wherein the compression unit comprises:
A fixed scroll fixed to the housing,
A movable scroll engaging with the fixed scroll and configured to revolve against the fixed scroll;
Wherein the compression chamber is divided by the fixed scroll and the movable scroll, and when the rotor rotates in a predetermined normal direction, the movable scroll is revolved in the forward direction, Compressing the suction fluid,
Wherein the motor-driven compressor has an injection port for introducing an intermediate-pressure fluid having a higher pressure than the suction fluid and lower than the compressed fluid into the compression chamber,
Wherein,
A deceleration control section that performs deceleration control for decelerating the rotor over a first period as the rotor rotates in a direction opposite to the forward direction,
And a continuation control section for executing continuation control to continue the rotation of the rotor over a second period longer than the first period after the execution of the deceleration control,
Wherein the difference in the number of revolutions of the rotor during the continuous control is a difference between the number of rotations of the rotor at the start timing of the deceleration control and the number of rotations of the rotor at the end timing of the deceleration control, Smaller motor compressor. The method according to claim 1,
Wherein the deceleration control section is configured to decelerate the rotor until the rotational speed of the rotor reaches a target rotational speed set to a predetermined allowable rotational speed or less,
And the continuation control section is configured to continue the rotation of the rotor while keeping the number of rotations of the rotor at or below the allowable number of rotations over the second period. 3. The method of claim 2,
And the continuation control unit is configured to control the drive circuit such that the number of rotations of the rotor is maintained at the target number of revolutions. 4. The method according to any one of claims 1 to 3,
Wherein the electric motor is a three-phase motor,
Wherein the driving circuit comprises:
Phase u-phase arm switching element and u-phase lower arm switching element connected to each other,
A v-phase ivory arm switching element and a v-phase lower arm switching element connected to each other,
Phase woof-arm switching element and a wo-phase lower arm switching element connected to each other,
The control unit is configured to control the switching of the three-phase armamentary switching element and the three-phase low arm switching element,
The deceleration control section controls the first mode in which one or a plurality of switching elements among the three-phase arm switching elements and the three-phase subsidiary arm switching elements are in the ON state and the other switching elements are in the OFF state in the deceleration control And the driving circuit is controlled by a switching control mode in which a combination of a switching element to be turned ON and a switching element to be turned OFF is different from the first aspect. 5. The method of claim 4,
Wherein the switching control mode in the deceleration control includes:
An embodiment in which the three-phase arm switching element is switched so as to sequentially change the ivory arm switching elements to be turned ON,
An embodiment in which the three-phase lower arm switching element is switched so that the lower arm switching elements to be turned ON sequentially change,
or,
Both of the three-phase arm switching element and the three-phase subsidiary arm switching element are switched so that the switching elements which are also in the ON state are sequentially switched so that the ivory arm switching element and the lower arm switching element of the same phase are not simultaneously turned ON The motor-driven compressor comprising: 6. The method of claim 5,
Wherein the deceleration control section starts the deceleration control by periodically turning on / off the three-phase target arm switching element to be a switching operation target with a predetermined initial deceleration switching pattern and an initial deceleration duty ratio, And at least one of a switching pattern and a duty ratio of the three-phase target arm switching element is controlled so as to be higher within a range not exceeding a predetermined allowable value. The method according to claim 6,
Wherein the initial deceleration switching pattern and the initial deceleration duty ratio are set so that the current flowing through the three-phase motor does not exceed the tolerance regardless of the number of revolutions of the rotor. 5. The method of claim 4,
The continuation control section periodically turns on / off the three-phase target arm switching element of at least one of the three-phase arm switching element and the three-phase subsidiary arm switching element with a predetermined initial continuation switching pattern and an initial continuation duty ratio, Phase motor to gradually control the current flowing to the three-phase motor, and to control at least one of the switching pattern and the duty ratio of the three-phase target arm switching element to be variable. The method according to claim 1,
And the control section is configured to perform a stop control to stop the rotation of the rotor after the completion of the continuation control.

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