JP6518506B2 - POWER SUPPLY DEVICE AND AIR CONDITIONER USING SAME - Google Patents

Description

  The present invention relates to a power supply device and an air conditioner using the same.

  A power supply device used for an air conditioner or the like has a function of rectifying and smoothing an AC voltage (electric power) received from an AC power supply into a DC voltage (electric power). At the same time, the power supply apparatus is required to have a function of improving the power factor and a function of coping with an excessive rush current generated when the power supply is turned on.

  A so-called capacitor input rectifying and smoothing circuit including a diode bridge and a smoothing capacitor is known as a basic circuit that rectifies and smoothes an AC voltage (power) to a DC voltage (power).

  There is also known a rectifying / smoothing circuit that replaces a part of the rectifying diode in the diode bridge with a switching element, provides a reactor between the switching element and the AC power supply, and performs power factor improvement and loss reduction by a boost chopper operation. . Furthermore, in this rectifying and smoothing circuit, a rectifying and smoothing circuit provided with a rectifying diode for bypassing the inrush current is known as a conventional technique for preventing an excessive inrush current generated at the time of power supply from flowing into the switching element to cause element failure. (See, for example, Patent Document 1).

Unexamined-Japanese-Patent No. 2004-72846 (FIG. 3)

  However, in the above prior art, although the failure of the switching element due to the inrush current can be prevented, by providing the rectifying diode for the inrush current bypass, the step-up chopper circuit effectively functions for loss reduction and power factor improvement. Becomes difficult. As a result, there is a problem that the efficiency of the power supply device and its application device is reduced. And this problem is remarkable especially when input voltage (electric power) is small.

  Thus, the present invention provides a power supply device and an air conditioner that are highly reliable and highly efficient against inrush current.

In order to solve the above problems, a power supply device according to the present invention includes a first series connection circuit in which a first rectification diode and a second rectification diode are connected in series, and a first switching element having a reverse conduction function. And a second series connection circuit in which the second switching element is connected in series are connected between the positive electrode and the negative electrode, and a circuit unit connected in parallel, and a smoothing capacitor connected between the positive electrode and the negative electrode And a third series connection circuit in which the third rectification diode and the fourth rectification diode are connected in series and the second rectification circuit and the fourth rectification diode are connected in parallel, an inductance element And an AC power supply is connected to the first series connection point in the first series connection circuit, and connected via a reactor to the third series connection point in the third series connection circuit. Is a third series connection point is connected to a second series connection point in the second series circuit via an inductance element, the inductance value of the inductance element is smaller than the inductance value of the reactor.

  Further, in order to solve the above problems, an air conditioner according to the present invention includes an electric compressor having a compressor driven by an AC motor, and a power supply device for supplying electric power to the electric compressor. The refrigerant compressed by the circuit circulates in the cooling and heating cycle, and the power supply device includes an inverter connected between the positive electrode and the negative electrode of the power supply device according to the present invention, and the power output from the inverter supplies the electric compressor Be done.

  According to the present invention, it is possible to suppress the inrush current flowing in the switching element without reducing the efficiency. Therefore, both the reliability and the efficiency of the power supply device and the air conditioner are improved.

  Problems, configurations, and effects other than those described above will be clarified by the description of the embodiments below.

It is a circuit diagram showing a power supply device which is Example 1 of the present invention. It is a circuit diagram which shows the power supply device for the electric compressor drive which is Example 2 of this invention. The capacitor input rectification smoothing circuit which is the comparative example 1 is shown. The rectification smoothing circuit provided with a step-up chopper circuit which is comparative example 2 is shown. The voltage waveform and current waveform of the input side of a capacitor input rectification smoothing circuit are shown. The voltage waveform and current waveform of the input side of a rectification smoothing circuit provided with a pressure | voltage rise chopper circuit are shown. The rectification smoothing circuit provided with the diode for inrush current bypass which is the comparative example 3 is shown. The rectification smoothing circuit provided with a step-up chopper circuit which is comparative example 4 is shown. It is a circuit diagram which shows the power supply device which is Example 4 of this invention. FIG. 10 is a cycle configuration diagram of an air conditioner of a fourth embodiment. FIG. 16 is an external view of an outdoor unit of an air conditioner of a fourth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, those with the same reference numerals indicate components having the same configuration or similar functions.

  FIG. 1 is a circuit diagram showing a power supply apparatus according to a first embodiment of the present invention.

  In FIG. 1, the power supply device 10 is a rectifier including rectifying diodes 11 a, 11 b, 12 a, 12 b which are first to fourth rectifying diodes, and a coil 15, and switching elements 13 a, 13 b which are first to second switching elements, respectively. A circuit portion, a reactor 14 and a smoothing capacitor 16 are provided. As the switching elements 13a and 13b, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are applied. The MOSFET has a reverse conduction function by a parasitic diode incorporated in the element. Therefore, although the MOSFET can be a path of inrush current, according to this embodiment, the inrush current flowing through the MOSFET is suppressed as described later.

  As shown in FIG. 1, the anode of the rectifier diode 11a and the cathode of the rectifier diode 11b are connected, and the rectifier diodes 11a and 11b are connected in series. The cathode of the rectifier diode 11 a is connected to the DC positive electrode side wire 101, and the anode of the rectifier diode 11 b is connected to the DC negative electrode side wire 102. Furthermore, the anode of the rectifier diode 12a and the cathode of the rectifier diode 12b are connected, and the rectifier diodes 12a and 12b are connected in series. The cathode of the rectifier diode 12 a is connected to the DC positive electrode side wire 101, and the anode of the rectifier diode 12 b is connected to the DC negative electrode side wire 102.

  The first output terminal (upper side in FIG. 1) of the single-phase AC power supply 201 is connected to a series connection point P3 of the rectifier diode 12 a and the rectifier diode 12 b via the reactor 14. The output terminal 2 (lower side in FIG. 1) is directly connected to a series connection point P1 of the rectifying diode 11a and the rectifying diode 11b. Therefore, the rectifying diodes 11a, 11b, 12a, 12b and the smoothing capacitor 16 constitute a so-called capacitor input rectifying and smoothing circuit. Therefore, according to this embodiment, smoothed DC voltage (power) can be output without performing synchronous rectification operation by the step-up chopper circuit including the switching elements 13a and 13b. That is, in the present embodiment, the alternating current voltage (power) input from the single phase alternating current power supply 201 is rectified by the diode bridge circuit including the rectifying diodes 11a, 11b, 12a and 12b, and the positive side wiring 101 and the negative side wiring A voltage (electric power) mainly composed of the rectified DC component is supplied to 102. The voltage (power) mainly composed of direct current supplied to the positive electrode side wire 101 and the negative electrode side wire 102 is converted to a direct current voltage smoothed by the action of the smoothing capacitor 16 and smoothed direct current voltage (power) Are supplied to the load 202.

  However, in a region where the input AC voltage is small, there is a section in which no current flows. This is because, since the rectifying diode has a diffusion potential at the PN junction, current does not flow if the voltage is small (approximately 0.7 to 0.8 V or less) even in the forward direction. As described above, when there is a section in which no current flows, the current waveform has a large difference from the sine waveform, and the power factor is lowered.

  On the other hand, in the present embodiment, the power factor is improved by the reactor 14 as follows. The reactor 14 functions to store and release electric energy. In addition, the reactor 14 has an action of generating a back electromotive force when a current flows. The action of the reactor 14 suppresses steep changes in current, and releases the stored energy even when the input voltage decreases, thereby reducing the slope and maximum value of the input current. As a result, the waveform of the current flowing through the rectifier circuit becomes relatively close to a sine wave, and the power factor is improved. The power factor improvement effect by the reactor 14 is effective even when the switching elements 13a and 13b are not switched and the power factor improvement operation is not performed.

  In the present embodiment, the switching elements 13a and 13b, the reactor 14, the coil 15, and the rectifying diodes 11a and 11b further constitute a step-up chopper circuit. More specifically, the source of the switching element 13a and the drain of the switching element 13b are connected, and the switching elements 13a and 13b are connected in series. The drain of the switching element 13 a is connected to the positive electrode side wire 101, and the source of the switching element 13 b is connected to the negative electrode side wire 102. The coil 15 is connected between a series connection point P2 of the switching elements 13a and 13b and a series connection point P3 of the rectifier diodes 12a and 12b. Accordingly, the series connection point P2 of the switching elements 13a and 13b is connected to the first output terminal (upper side in FIG. 1) of the AC power supply 201 via the coil 15 and the reactor 14. Further, as described above, the series connection point P1 of the rectifier diodes 11a and 11b in the rectifier circuit is connected to the second AC output terminal (the lower side in FIG. 1) of the AC power supply 201.

  Therefore, in the present embodiment, between the series connection point P1 of the diodes 11a and 11b and the series connection point P2 of the switching elements 13a and 13b, the AC power from the AC power supply 201 passes through the reactor 14 and the rectifier circuit portion of the step-up chopper circuit. Is input to At this time, the AC power supply 201 is connected between the series connection point P1 of the diodes 11a and 11b and the series connection point P3 of the diodes 12a and 12b via the reactor 14, and further the switching elements 13a and 13b via the coil 15. Are connected to the series connection point P2 of That is, in the present embodiment, AC power is input to the rectifier circuit portion of the step-up chopper circuit via the reactor 14 and the coil 15.

  Here, although the reactor 14 and the coil 15 are inductance elements in the step-up chopper circuit, in the present embodiment, the value of the inductance of the coil 15 is set to a value smaller than the value of the inductance of the reactor 14. For example, the inductance of the coil 15 and the inductance of the reactor 14 are set to several tens of μH and several mH, respectively. Therefore, substantially only the reactor 14 of the reactor 14 and the coil 15 functions as a step-up inductance element in the step-up chopper circuit. In the step-up chopper circuit, coil 15 functions as a so-called conductor for connecting reactor 14 to series connection point P2 of switching elements 13a and 13b. In addition, the other function of the coil 15 in the power supply device of a present Example is mentioned later.

  The step-up chopper circuit according to the first embodiment has the step-up function, the synchronous rectification function, and the function of improving the power factor, as described below.

  In the present embodiment, when performing the step-up operation, the synchronous rectification operation, and the power factor correction operation, the switching elements 13a and 13b complementarily repeat short circuit opening, that is, on and off (this is referred to as complementary symmetrical operation). The electric energy is accumulated and released in the reactor 14 by the repetition of the on and off.

  When switching element 13b is turned on in the positive half cycle of single phase AC power supply 201, the first output terminal (upper side in FIG. 1) of single phase AC power supply 201, reactor 14, switching element 13b, diode 11b, single phase AC A current flows in the path of the second output terminal (lower side in FIG. 1) of the power supply 201, and electrical energy is stored in the reactor. At this time, a current due to the inductance of the reactor 14 and the voltage of the single-phase AC power supply 201 flows in the reactor 14. This current flows even in a section where the voltage of the AC power supply 201 is lower than the voltage of the smoothing capacitor 16 because the path does not include the smoothing capacitor 16. As a result, the current waveform is substantially sinusoidal, and the power factor is improved.

  Next, when the switching element 13b is turned off and the switching element 13a is turned on, the electrical energy stored in the reactor 14 is released through the path of the reactor 14, the coil 15, the switching element 13a, the smoothing capacitor 16, and the rectifying diode 11b. , Current flows in this path. Thereby, the smoothing capacitor 16 is charged to a voltage higher than the power supply voltage. That is, in the power supply device of the first embodiment, the boosting operation is performed. Here, although a current path including the rectifying diode 12a is also considered, the ON resistance of the switching element 13a is smaller than that of the rectifying diode 12a, and as described above, since the inductance of the coil 15 is smaller than that of the reactor 14, the rectifying diode 12a is It is difficult for current to flow in That is, the rectifying diode 12a does not function much in the rectifying circuit, and instead, the switching element 13a performs a so-called synchronous rectification operation. For this reason, the power loss of the rectifier circuit portion can be reduced. In particular, when the AC voltage (power) to be input is small and the DC voltage (power) to be output is small, the power loss reduction effect by the synchronous rectification operation is large.

  When the switching element 13a is turned on in the negative half cycle of the single phase AC power supply 201, the second output terminal of the single phase AC power supply 201, the diode 11a, the switching element 13a, the reactor 14, the first phase AC power supply 201 Current flows in the path of the output terminal of the power supply, and electrical energy is stored in the reactor 14. At this time, as in the case of the positive half cycle of the single-phase AC power supply 201, the current waveform is substantially sinusoidal, so that the power factor is improved.

  Next, when the switching element 13a is turned off and the switching element 13b is turned on, the electrical energy stored in the reactor 14 is released by the path of the rectifying diode 11a, the smoothing capacitor 16, the switching element 13b and the reactor 14, Current flows to Thus, the boosting operation is performed as in the positive half cycle of the single-phase AC power supply 201. In addition, since the on resistance of the switching element 13b is smaller than that of the rectifying diode 12a and the inductance of the coil 15 is smaller than that of the reactor 14, current hardly flows in the rectifying diode 12b. That is, the rectifying diode 12b does not function much in the rectifying circuit, and instead, the switching element 13b performs a so-called synchronous rectification operation. For this reason, the power loss of the rectifier circuit portion can be reduced.

  In the present embodiment, MOSFETs are used as the switching elements 13a and 13b, but when the MOSFET is on, a PN junction such as a diode is provided in the current path including the channel in the element of the MOSFET. Because it is not included, the on-resistance can be made sufficiently lower than the diodes 12a and 12b. Therefore, in the synchronous rectification operation, the current can not flow in the diodes 12a and 12b, and the entire current can flow in the switching elements 13a and 13b, and the power loss in the rectification operation can be reduced.

  In addition, by applying a super junction MOSFET with lower on resistance as the MOSFET, power loss of the power supply device can be reduced.

  In FIG. 1, diodes are connected in anti-parallel to the switching elements 13a and 13b, which are parasitic diodes formed inside the MOSFET. In the on state of the MOSFET, current flows to a region including a channel having a low resistance, and almost no current flows in parasitic diodes as well as the diodes 12a and 12b.

  Also, in order for the synchronous rectification operation to function sufficiently, it is preferable to make the inductance of the coil 15 smaller than the inductance of the reactor 14 as in this embodiment. For example, the inductance of the reactor 14 is preferably set to 1 mH or more and less than 10 mH, and the inductance of the coil 15 is set to 10 μH or more and less than 100 μH. Thereby, during normal operation, that is, when the step-up chopper circuit performs normal operation, the impedance of the rectifier diode 12a becomes larger than the series impedance of the switching element 13a and the coil 15, and the impedance of the rectifier diode 12b is switched to the switching element 13b and It becomes larger than the series impedance of the coil 15. That is, for the same current during normal operation, the voltage drop of the rectifying diode 12a becomes larger than the voltage drop of the series connection of the switching element 13a and the coil 15, and the voltage drop of the rectifying diode 12b becomes the switching element 13b and the coil It becomes larger than the voltage drop of 15 series connection. Therefore, in the normal operation, current can be reliably supplied to the switching elements 13a and 13b.

  In this embodiment, the power loss reduction effect by the synchronous rectification operation is high particularly in the low current region where the back electromotive force of the coil 15 is small. When the current increases and the back electromotive force of the coil 15 increases, the synchronous rectification operation may not be sufficient. On the other hand, in this embodiment, the rectification operation is performed by the rectification circuit formed of a diode bridge circuit including the rectification diodes 11a and 11b in the rectification circuit portion of the step-up chopper circuit and the rectification diodes 12a and 12b not contributing to the synchronous rectification operation. Secured. At this time, the voltage drop of the switching element increases in proportion to the current, while the non-linearity of the current-voltage characteristic of the rectifier diode suppresses the increase of the voltage drop of the rectifier diode, so that the power loss in the high current region The increase in

  As described above, the step-up chopper circuit according to the first embodiment has the synchronous rectification function and the power factor improvement function in addition to the step-up function by the complementary on / off control of the switching elements 13a and 13b. The switching elements 13a and 13b are on / off controlled by applying a control signal to a control terminal (gate terminal) of the switching element by a control circuit not shown in FIG. The control circuit generates a control signal by, for example, a pulse width modulation (PWM) method. In this case, the first embodiment performs the boosting operation, the synchronous rectification operation, and the power factor correction operation according to the pulse width and timing of the control signal. In the step-up chopper circuit, the magnitude of the output DC voltage can be changed by adjusting the on and off periods of the pulse.

  Next, the inrush current suppression function of the coil 15 will be described. Although both the reactor 14 and the coil 15 are inductance elements, there is a difference between the inductance value and the main functions (reactor 14 for boosting and power factor improvement, and the coil 15 for inrush current suppression). Other names are used for convenience to clarify that there is something.

  In the circuit of FIG. 1, an inrush current flows from the AC power supply 201 to the smoothing capacitor 16 via the rectifying diodes 11a, 11b, 12a, 12b when the power is turned on. For example, when a positive half cycle voltage is applied, an inrush current flows in a path including the reactor 14, the rectifying diode 12a, the smoothing capacitor 16, and the rectifying diode 11b. Here, since the forward direction of the built-in diodes of the switching elements 13a and 13b is the direction in which the inrush current flows, the rush current may also flow in the switching elements 13a and 13b even if the switching elements 13a and 13b are off. There is.

  Therefore, in the present embodiment, the coil 15, that is, the inductance element is inserted into the inrush current path via the switching element 13a or 13b. Since the back electromotive force is generated for the abrupt change of the inrush current by the inductance of the coil 15, the inrush current flowing through the switching elements 13a and 13b is suppressed.

  Furthermore, since the switching elements 13a and 13b are connected in parallel with the rectifying diodes 12a and 12b via the coil 15 in the path of the inrush current, the inrush current is generated from the switching elements and the diodes 12a and 12b. And the rectifier circuit. That is, the inrush current is bypassed by the diodes 12a and 12b. As a result, excessive inrush current is suppressed from flowing through the switching elements 13a and 13b and the rectifier circuit.

  Thus, the inrush current flowing through the switching elements 13a and 13b and the rectifier circuit is suppressed by suppressing the inrush current flowing through the switching elements 13a and 13b by the coil 15 and dividing the inrush current by the switching element and the rectifier circuit. , And the failure of the switching element and the rectifying diode can be prevented.

  The inductance of the coil 15 is preferably set to 10 μH or more and less than 100 μH. Thereby, the impedance of the rectifier diode 12a becomes smaller than the series impedance of the switching element 13a and the coil 15 with respect to the rush current, and the impedance of the rectifier diode 12b becomes smaller than the series impedance of the switching element 13b and the coil 15. . That is, for the same inrush current, the voltage drop of the rectifying diode 12a becomes smaller than the voltage drop of the series connection of the switching element 13a and the coil 15, and the voltage drop of the rectifying diode 12b becomes the series of the switching element 13b and the coil 15. Less than the voltage drop of the connection. Therefore, the inrush current can be reliably bypassed to the rectifying diodes 12a and 12b.

  As described above, according to the first embodiment, the rectifying diodes 12a and 12b serving as a bypass for rush current are provided, and between the connecting point P3 of the rectifying diodes 12a and 12b and the connecting point P2 of the switching elements 13a and 13b. By connecting the coil 15 having a small inductance to the inrush current flowing through the switching elements 13a and 13b is suppressed. Thereby, the failure of the switching elements 13a and 13b due to the rush current can be prevented. Furthermore, during normal operation, current flows in the current path including the switching elements 13a and 13b. Thereby, even if the rectifying diodes 12a and 12b are provided, the synchronous rectification operation and the power factor improving operation accompanying the on / off operation of the switching elements 13a and 13b in the step-up chopper operation are not inhibited by the rectifying diodes 12a and 12b. It becomes effective. Therefore, the power supply apparatus is less likely to fail with respect to the inrush current, the reliability is improved, the loss is reduced, and the efficiency is improved.

  Hereinafter, in order to clarify the effect of Example 1 of this invention mentioned above, a comparative example and its subject are demonstrated. The problems described below are solved by the first embodiment as described above.

  FIG. 3 shows, as Comparative Example 1, a capacitor input rectifying and smoothing circuit that receives an AC power supply and generates a DC voltage (electric power). FIG. 5 shows voltage waveforms and current waveforms on the input side of the capacitor input rectifying and smoothing circuit shown in FIG.

  As shown in FIG. 3, in the first comparative example, the rectifier circuit is configured of a diode bridge including the rectifying diodes 11 a, 11 b, 12 a and 12 b. The AC power supply 201 supplies an AC voltage (power) to a pair of AC input terminals of the rectifier circuit. The rectifying circuit (rectifying diodes 11a, 11b, 12a, 12b) rectifies AC voltage and supplies a voltage (electric power) mainly composed of a DC component to the smoothing capacitor 16 via the positive electrode side wire 101 and the negative electrode side wire 102. . The voltage (power) smoothed by the smoothing capacitor 16 is supplied to the load 202.

  In the first comparative example, as shown in FIG. 5, the current 1002 does not flow in a section where the voltage 1001 applied to the pair of AC input terminals is lower than the voltage of the smoothing capacitor 16. Therefore, the current waveform has a large difference from the sine wave, and the power factor is lowered.

  FIG. 4 shows, as Comparative Example 2, a rectifying and smoothing circuit provided with a step-up chopper circuit. Further, FIG. 6 shows a voltage waveform and a current waveform on the input side of the rectifying and smoothing circuit of the second comparative example.

  As shown in FIG. 4, in this comparative example 2, a part of the rectifier circuit in comparative example 1 (FIG. 3), that is, the rectifying diodes 12a and 12b are replaced with switching elements 13a and 13b, and switching elements 13a and 13b and AC power supply A reactor 14 is provided between the two. Thus, the comparative example 2 performs the step-up chopper operation and performs the power factor improvement operation along with the step-up chopper operation.

  In the reactor 14, a current flows due to the inductance and the input power supply voltage. This current flows regardless of the magnitude of the voltage of the smoothing capacitor 16 along with the step-up chopper operation. As a result, as shown in FIG. 6, the current 1003 can flow even in a section where the voltage 1001 of the AC power supply 201 is lower than the voltage of the smoothing capacitor 16. That is, by storing and releasing the electric energy in the reactor 14, a current flows even in a section where the input voltage of the AC power supply 201 is small. For this reason, since the waveform of the current 1003 can be made sinusoidal, the power factor is improved.

  In Comparative Example 2, since the smoothing capacitor 16 is not charged when the power is turned on, rush current flows when the power is turned on. Therefore, as the rectifying diodes 11a and 11b, diodes having a non-repetitive surge resistance that can withstand this inrush current are used. However, since the switching elements 13a and 13b have a surge withstand capacity lower than that of the rectifying diode, there is a fear that the switching elements 13a and 13b may fail if an excessive inrush current flows.

  FIG. 7 shows, as Comparative Example 3, a rectifying and smoothing circuit including an inrush current bypass diode.

  As shown in FIG. 7, in the third comparative example, in order to suppress the inrush current flowing through the switching elements 13a and 13b, rectifier diodes 11c and 11d serving as bypasses of the inrush current are provided.

  However, in the third comparative example, the power supply current flows to the rectifying diodes 11 c and 11 d even in the normal operation due to the back electromotive force generated in the reactor 14. Therefore, even if the switching elements 13a and 13b are used, it is difficult to sufficiently reduce the power loss of the power supply device.

  FIG. 8 shows, as Comparative Example 4, a rectifying and smoothing circuit provided with a step-up chopper circuit.

  In the fourth comparative example, as shown in FIG. 8, the rectifier circuit including the rectifier diodes 11 a to 11 d rectifies an AC voltage, and a voltage mainly composed of a DC component is applied to the positive electrode side wire 111 and the negative electrode side wire 102. Output. A boost chopper circuit comprising a reactor 24, a switching element 26, and a reverse blocking diode 25 provided at the subsequent stage of the rectifier circuit outputs a DC voltage (electric power) to the smoothing capacitor 16 by a boost operation and performs a power factor improvement operation. Then, a voltage (electric power) is supplied to the load 202 from the positive side wiring 121 and the negative side wiring 102 at both ends of the smoothing capacitor 16.

Here, the operation of the boost chopper circuit and a reverse blocking diode 2 5.

  As shown in FIG. 8, when the reactor 24 short-circuits between the output terminals of the rectifier circuit that outputs the full-wave rectified voltage via the switching element 26, a current flows due to the voltage and the inductance of the reactor 24. This current flows regardless of the voltage of the smoothing capacitor 16 by the reverse blocking diode 25 connected between the connection point of the reactor 24 and the switching element 26 and the high potential side of the smoothing capacitor 16. Therefore, current can flow even during a period in which the voltage of the AC power supply 201 is lower than the voltage of the smoothing capacitor 16, and it becomes possible to obtain a current waveform as shown in FIG.

  When the switching element 26 is turned off, no current flows in the switching element 26, but the current in the reactor 24 can not change (in this case, decrease) sharply due to the action of the inductance. Therefore, the reactor 24 generates a back electromotive force to keep the current flow, and flows a current for charging the smoothing capacitor 16 via the reverse blocking diode 25. The current waveform can be made sinusoidal by repeating this operation.

  The comparative example 4 is not a circuit configuration to be considered for suppressing inrush current to the switching element, but the AC power supply voltage is rectified only by the rectifying diode, and the reverse blocking diode 25 is required, so It is difficult to reduce.

  FIG. 2 is a circuit diagram showing a power supply device for driving an electric compressor according to a second embodiment of the present invention. Hereinafter, differences from the first embodiment will be mainly described, and the description of the same components as the first embodiment will be omitted.

  In the power supply device 20 in FIG. 2, the DC input side of the inverter 17 is connected to the DC output of the power supply device 10 of the first embodiment shown in FIG. 1. As a result, the direct current voltage (power) output to both ends of the smoothing capacitor 16 is converted by the inverter 17 into an alternating current voltage (power) whose frequency and voltage are variable. That is, while the power supply apparatus 10 (FIG. 1) of the first embodiment is a power supply apparatus which receives an AC voltage (power) from an AC power supply and outputs a DC voltage (power), the power supply apparatus of the second embodiment Reference numeral 20 denotes a power supply device which receives an AC voltage (electric power) from a commercial AC power supply or the like and outputs an AC voltage (electric power).

  In FIG. 2, the inverter 17 is configured to include switching elements 18 a, 18 b, 18 c, 18 d, 18 e and 18 f formed of MOSFETs. A U-phase switching leg is configured by the switching element 18a serving as the upper arm and the switching element 18b serving as the lower arm. Also, a switching leg of V phase is configured by the switching element 18c serving as the upper arm and the switching element 18d serving as the lower arm. Furthermore, a switching leg of the W phase is configured by the switching element 18e serving as the upper arm and the switching element 18f serving as the lower arm.

  The high potential side and the low potential side of these U-phase, V-phase and W-phase switching legs are connected to the positive electrode side wire 101 and the negative electrode side wire 102 to which the smoothing capacitor 16 is connected, respectively. Thereby, a direct current voltage (electric power) is supplied to the inverter 17 using the power supply device 10 (FIG. 1) of the first embodiment as a direct current power supply.

  The switching elements 18a, 18b, 18c, 18d, 18e and 18f are supplied with a predetermined control signal from control circuits (not shown) to control terminals (gate terminals) of the switching elements 18a, 18b, 18c, 18d, 18e and 18f. It is on / off controlled by giving. Thereby, a three-phase AC voltage (electric power) is output from U-phase, V-phase and W-phase switching legs by U-phase AC output 103U, V-phase AC output 103V and W-phase AC output 103W, respectively. .

  The three-phase AC voltage (electric power) output from the inverter 17 has a variable frequency by changing the timing of on / off control of the switching elements 18a, 18b, 18c, 18d, 18e, 18f by the control circuit. . Further, the magnitude of the DC voltage at both ends of the smoothing capacitor 16 becomes variable by changing the timing of on / off control of the switching elements 13a and 13b of the step-up chopper circuit. As a result, the voltage amplitude of the three-phase AC voltage (power) output from the inverter 17 becomes variable.

  The three-phase AC voltage (voltage) output from the inverter 17 is supplied to the electric compressor 203 whose compressor is driven by the three-phase AC motor. As a three-phase alternating current motor, for example, a permanent magnet synchronous motor is applied.

  As a control circuit of the inverter 17, for example, a PWM type control circuit is applied. Moreover, it is preferable that the control circuit of the inverter 17 and the control circuit which controls switching of switching element 13a, 13b by the side of a DC power supply are a control circuit integrated. As a result, the control circuit can be miniaturized as the whole control circuit of the power supply device 20, and the control accuracy is improved.

  As described above, according to the second embodiment, since the DC power supply of the inverter 17 is configured by the power supply device according to the first embodiment, the power supply device that outputs three-phase alternating current of variable voltage and variable frequency As a result, it is difficult to fail and the reliability is improved, and the loss is reduced and the efficiency is improved.

  The switching element constituting the inverter 17 is not limited to the MOSFET, but may be an IGBT (Insulated Gate Bipolar Transistor) or a super junction MOSFET.

  FIG. 9 is a circuit diagram of a power supply apparatus according to a third embodiment of the present invention. Hereinafter, differences from the first embodiment will be mainly described, and the description of the same components as the first embodiment will be omitted.

  The power supply apparatus of the third embodiment differs from the first embodiment (FIG. 1) in that the AC power supply is a three-phase AC power supply 301. Therefore, the power supply device 10 includes two rectifying diodes (11a and 11b in FIG. 1), two switching elements (13a and 13b in FIG. 1), and two rectifying diodes (for bypassing inrush current). In FIG. 1, three rectifier circuits, each including 12a and 12b) and a coil (15 in FIG. 1) for suppressing inrush current flowing through the switching element, are provided according to the number of phases of the AC power supply. A three-phase AC voltage (electric power) is input from the three-phase AC power supply 301 to the three rectifier circuits via the three reactors 14a, 14b, and 14c.

  That is, as shown in FIG. 9, the third embodiment flows through the rectifying diodes 11a and 11b, the switching elements 13a and 13b, the rectifying diodes 12a and 12b for bypassing the rush current, and the switching elements 13a and 13b. A first rectifier circuit portion including a coil 15a for suppressing inrush current, rectifier diodes 11c and 11d, switching elements 13c and 13d, rectifier diodes 12c and 12d for bypassing inrush current, and switching elements 13c, A second rectifier circuit unit including a coil 15b for suppressing inrush current flowing to 13d, rectifying diodes 11e and 11f, switching elements 13e and 13f, rectifying diodes 12e and 12f for bypassing inrush current, and switching Suppress the inrush current flowing to elements 13e and 13f It includes a third rectifier circuit consisting of a yl 15c, a.

  The first, second and third rectifier circuits respectively have a U-phase terminal of the three-phase AC power supply 301 via the reactor 14a, a V-phase terminal via the reactor 14b, and a W-phase terminal via the reactor 14c. Connected, and a three-phase AC voltage (power) is input. Then, each rectifier circuit unit operates in the same manner as the first embodiment, whereby the power supply device 10 of the third embodiment converts the three-phase AC voltage (power) input from the three-phase AC power source into a DC voltage (power). Output. The output DC voltage (power) is supplied to the load 202.

  In the third embodiment, the voltage between the U- and V-phase terminals of the three-phase AC power supply 301, the voltage between the V- and W-phase terminals, and the voltage between the W- and U-phase terminals. The line voltage is input to the first rectifier circuit unit, the second rectifier circuit unit, and the third rectifier circuit unit in the power supply device 10.

  According to the power supply device of the third embodiment, as in the first embodiment, the rectifier diodes 12a to 12f serving as bypasses of the inrush current are provided, and the rush current flowing to the switching elements 13a to 13f by the coils 15a to 15c having small inductances. The current is suppressed. Thereby, failure of the switching elements 13a to 13f due to rush current can be prevented. In addition, during normal operation, current flows in a current path including the switching elements 13a to 13f. Thereby, the synchronous rectification operation and the power factor improvement operation accompanying the on / off operation of the switching elements 13a to 13f in the step-up chopper operation become effective without being blocked by the inrush current bypassing rectification diodes 12a to 12f. Therefore, the power supply apparatus that outputs a DC voltage (power) using an AC power supply as a three-phase AC power supply improves the reliability against inrush current, reduces loss, and improves efficiency.

  Next, an air conditioner according to a fourth embodiment of the present invention will be described.

  The air conditioner according to the fourth embodiment is a motor-driven compressor in which the compressor is driven by a three-phase AC motor, and a power supply device for supplying a three-phase AC voltage (electric power) to the motor compressor. The power supply device 20 of Example 2 is provided. The electric compressor provided in the air conditioner of the fourth embodiment corresponds to the electric compressor 203 in FIG.

  Hereinafter, the air conditioner according to the fourth embodiment will be further described with reference to FIGS. 10 and 11.

  FIG. 10 is a cooling / heating cycle configuration diagram of the air conditioner of the fourth embodiment. The air conditioner includes an indoor heat exchanger 51, an outdoor heat exchanger 52, a compressor 53, an expansion valve 54, a four-way valve 55, an indoor blower fan 56, and an outdoor blower fan 57. The compressor 53, the outdoor heat exchanger 52, the outdoor blower fan (propeller fan) 57 and the expansion valve 54 are disposed in the outdoor unit (see FIG. 11), and the indoor heat exchanger 51 and the indoor blower fan 56 are indoor units (shown in FIG. Is placed).

  During the cooling operation, the high temperature and high pressure refrigerant discharged from the compressor 53 flows into the outdoor heat exchanger 52 through the four-way valve 55. The refrigerant that has flowed into the outdoor heat exchanger 52 is condensed by heat exchange with the outdoor air sent by the outdoor blower fan 57, and becomes a liquid refrigerant. The liquid refrigerant passes through the expansion valve 54 to become a low-temperature low-pressure two-phase refrigerant and flows into the indoor heat exchanger 51. The low-temperature low-pressure two-phase refrigerant flowing into the indoor heat exchanger 51 exchanges heat with the indoor air sent by the indoor blower fan 56. At this time, the indoor air sent to the indoor heat exchanger 51 is cooled by the low-temperature low-pressure two-phase refrigerant flowing into the indoor heat exchanger 51, and is discharged into the room from a blowout port (not shown). Since the air discharged into the room from the blowout port (not shown) is lower than the temperature of the air at the suction port (not shown), the temperature of the room can be lowered. The refrigerant heat-exchanged by the indoor heat exchanger 51 returns to the compressor 53 again via the four-way valve 55.

  During the heating operation, the high temperature and high pressure refrigerant discharged from the compressor 53 flows into the indoor heat exchanger 51 via the four-way valve 55. Then, it passes through the four-way valve 55 and the outdoor heat exchanger 52, and returns to the compressor 53 via the four-way valve 55.

  FIG. 11 is an external view of the outdoor unit of the air conditioner of the fourth embodiment. The space in the outdoor unit is divided into a compressor chamber A in which the compressor 53 is installed and a blower chamber B in which the outdoor blower fan 57 is installed, with the partition plate 70 interposed therebetween. Electrical components 79, such as a power supply device for driving the compressor 53, are housed between the compressor 53 and the upper lid 80 in a position straddling the compressor chamber A and the blower chamber B while being housed in the electrical box. is set up. The electrical component 79 is positioned above the partition plate 70 and supported by the partition plate 70.

  The outdoor air is sucked from the rear side of the outdoor unit by the outdoor blower fan 57, passes through the outdoor heat exchanger 52, and is blown out from the front side (front panel 81) of the outdoor unit.

  A variable voltage and variable frequency three-phase AC voltage (electric power) is supplied by the power supply device 20 of the second embodiment to the compressor 53, that is, the three-phase AC motor included in the electric compressor, and the three-phase AC motor rotates. The compressor 53 is driven by the AC motor. Thus, the air conditioner performs the cooling and heating operations as described above.

  According to the air conditioner of the fourth embodiment, the occurrence of inrush current in the power supply device of the compressor is less likely to cause a failure, and the reliability is improved. Moreover, since the loss is reduced and the efficiency is improved, energy saving of the air conditioner can be achieved.

  The present invention is not limited to the embodiment described above, and includes various modifications. For example, the embodiments described above are described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. In addition, it is possible to add, delete, and replace another configuration for part of the configuration of each embodiment.

  For example, the DC power supply unit in the second embodiment may be replaced with the power supply device of the third embodiment. Further, the power supply device of the second embodiment is not limited to one for driving an electric compressor, and can be applied to various devices driven by an electric motor. Further, the power supply devices of the first embodiment and the third embodiment can supply a DC voltage (electric power) not only to the inverter but also to various devices using DC power. Furthermore, the power supply apparatus of Example 1 and Example 3 is applicable not only to an air conditioner but as a DC power supply part of various apparatuses. The switching elements 13a and 13b of the step-up chopper circuit are not limited to the MOSFETs, and may be IGBTs having a reverse conduction function.

DESCRIPTION OF SYMBOLS 10 and 20 Power supply device 11a, 11b, 11c, 11e, 11f Rectification diode 12a, 12b, 12c, 12d, 12e 12f Rectification diode 13a, 13b, 13c, 13d, 13e, 13f Switching element 14, 14a, 14b, 14c Reactor 15, 15a, 15b, 15c Coil 16 Smoothing capacitor 17 Inverter 18a, 18b, 18c, 18d, 18e, 18f Switching element 51 Indoor heat exchanger 52 Outdoor heat exchanger 53 Compressor 54 Expansion valve 55 Four-way valve 56 Indoor ventilation Fan 57 Outdoor blower fan 70 Partition plate 79 Electrical component 80 Upper lid 81 Front panel 101 Positive side wiring 102 Negative side wiring 201 AC power supply 202 Load 203 Electric compressor 301 Three-phase AC power supply

Claims (8)

A first series connection circuit in which a first rectification diode and a second rectification diode are connected in series, a second switching element in which a first switching element having a reverse conduction function and a second switching element are connected in series A series connection circuit is connected between the positive electrode and the negative electrode, and a circuit unit connected in parallel;
A smoothing capacitor connected between the positive electrode and the negative electrode;
Equipped with
The circuit unit is
A third series connection circuit in which a third rectification diode and a fourth rectification diode are connected in series and are connected in parallel to the second series connection circuit;
An inductance element,
Have
An alternating current power supply is connected to a first series connection point in the first series connection circuit, and is connected via a reactor to a third series connection point in the third series connection circuit,
The third series connection point is connected to a second series connection point in the second series connection circuit via the inductance element ,
A power supply device characterized in that a value of inductance of the inductance element is smaller than a value of inductance of the reactor . In the power supply device according to claim 1,
The power supply device , wherein a value of inductance of the inductance element is 10 μH or more and less than 100 μH, and a value of inductance of the reactor is 1 mH or more and less than 10 mH . The power supply device according to claim 1 , wherein the first switching element and the second switching element are switch-controlled to be turned on and off complementarily . In the power supply device according to claim 1,
A power supply apparatus characterized in that AC power from the AC power supply is single phase, and only one circuit unit is provided . In the power supply device according to claim 1,
A power supply apparatus comprising a plurality of the circuit units, the number of which is equal to the number of phases of alternating current power from the alternating current power supply. In the power supply device according to claim 1,
Furthermore, the power supply device characterized by comprising an inverter connected between the positive electrode and the negative electrode . In the power supply device according to claim 1,
A power supply device characterized in that the first switching element and the second switching element are MOSFETs . A motor-driven compressor whose compressor is driven by an AC motor;
A power supply for supplying power to the electric compressor;
Equipped with
In an air conditioner, a refrigerant compressed by the electric compressor circulates in an air conditioning cycle,
The power supply device
A first series connection circuit in which a first rectification diode and a second rectification diode are connected in series, a second switching element in which a first switching element having a reverse conduction function and a second switching element are connected in series A series connection circuit is connected between the positive electrode and the negative electrode, and a circuit unit connected in parallel;
A smoothing capacitor connected between the positive electrode and the negative electrode;
Equipped with
The circuit unit is
A third series connection circuit in which a third rectification diode and a fourth rectification diode are connected in series and are connected in parallel to the second series connection circuit;
An inductance element,
Have
An alternating current power supply is connected to a first series connection point in the first series connection circuit, and is connected via a reactor to a third series connection point in the third series connection circuit,
The third series connection point is connected to a second series connection point in the second series connection circuit via the inductance element,
The value of the inductance of the inductance element is smaller than the value of the inductance of the reactor,
Furthermore, an inverter connected between the positive electrode and the negative electrode is provided,
An electric power output from the inverter is supplied to the electric compressor.

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