CN115622471A

CN115622471A - Motor drive system

Info

Publication number: CN115622471A
Application number: CN202210812187.XA
Authority: CN
Inventors: 阿部晋也
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2021-07-13
Filing date: 2022-07-11
Publication date: 2023-01-17
Also published as: JP2023012386A

Abstract

The invention provides a motor drive system capable of properly transmitting power from a power supply connected with an inverter with abnormality to a power supply connected with an inverter without abnormality with a simple structure. A motor drive system (1) is provided with: the vehicle-mounted power generation system comprises a first inverter (20), a second inverter (30), a motor generator (10) connected with the first inverter and the second inverter respectively, a first battery (41) connected with the first inverter, a second battery (42) connected with the second inverter, and a control device (50) capable of controlling the first inverter and the second inverter. When any one of the arm elements (21-26) of the first inverter (20) is failed, if the positive direction of the d-axis of the rotor is included in an angle range corresponding to a normal state during a period in which the drive of the motor generator (10) is stopped, the control device performs power transmission from the first battery to the second battery using the normal phase.

Description

Motor drive system

Technical Field

The present invention relates to a motor drive system.

Background

Patent document 1 describes a rotating electric machine drive system including: a first inverter connected to one end of a coil of the motor generator and the first battery; a second inverter connected to the other end of the coil of the motor generator and the second battery; and a low-potential-side connection line that connects a low potential side of the lower arm element of the first inverter and a low potential side of the lower arm element of the second inverter, and is provided with a low-potential-side switch.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016c181948

Disclosure of Invention

Problems to be solved by the invention

When an abnormality occurs in any of a plurality of inverters connected to different power sources, if it is possible to transmit power of the power source connected to the inverter in which the abnormality has occurred to a power source connected to an inverter in which no abnormality has occurred, effective use of the power can be achieved. However, in the conventional technology, there is room for improvement from the viewpoint of appropriately performing power transmission from a power supply connected to an inverter in which an abnormality has occurred to a power supply connected to an inverter in which no abnormality has occurred with a simple configuration.

The invention provides a motor drive system which can properly transmit power from a power supply connected with an inverter with abnormality to a power supply connected with an inverter without abnormality by a simple structure.

Means for solving the problems

The present invention provides a motor drive system, which comprises:

a first inverter provided with a plurality of arm elements;

a second inverter provided with a plurality of arm elements;

a motor having one end of a stator winding connected to an output portion of the first inverter and the other end of the stator winding connected to an output portion of the second inverter;

a first power supply connected to an input of the first inverter;

a second power supply connected to an input of the second inverter; and

a control device capable of controlling the first inverter and the second inverter, wherein,

the control device is capable of performing power transmission from the first power supply to the second power supply with a normal phase in the case where a failure occurs in any arm element of the first inverter,

the control device performs the power transmission when a positive direction of a d-axis of a rotating member of the motor is included in a predetermined angle range corresponding to the normal state when driving of the motor is stopped.

Effects of the invention

According to the present invention, it is possible to provide a motor drive system capable of appropriately performing power transmission from a power supply connected to an inverter in which an abnormality has occurred to a power supply connected to an inverter in which no abnormality has occurred with a simple configuration.

Drawings

Fig. 1 is a diagram showing an example of a motor drive system 1.

Fig. 2 is a diagram showing an example of control of each switching element during power transmission when an open failure occurs in the switching element on the high potential side in the first inverter 20.

Fig. 3 is a diagram showing an example of control of each switching element during power transmission when a short-circuit fault occurs in the switching element on the low potential side in the first inverter 20.

Fig. 4 is a diagram showing an example of control of each switching element during power transmission in the case where a short-circuit fault occurs in the switching element on the high potential side in the first inverter 20.

Fig. 5 is a diagram showing an example of control of each switching element during power transmission when an open failure occurs in the switching element on the low potential side in the first inverter 20.

Fig. 6 is a diagram (1 thereof) showing an example of an angular range of the d-axis of the rotor as a condition for power transmission using the U-phase and the V-phase.

Fig. 7 is a view (2) showing an example of the angular range of the d-axis of the rotor as a condition for power transmission using the U-phase and the V-phase.

Fig. 8 is a flowchart showing an example of the control process of the motor drive system 1 performed by the control device 50.

Description of reference numerals:

1. motor drive system

10. Motor generator (Motor)

20. First inverter

21 U1 Upper arm element (arm element)

22 V1 Upper arm element (arm element)

23 W1 Upper arm component (arm component)

24 Lower arm element of U1 (arm element)

25 Lower arm element of V1 (arm element)

26 W1 lower arm element (arm element)

30. Second inverter

31 U2 Upper arm element (arm element)

32 V2 Upper arm element (arm element)

33 W2 Upper arm element (arm element)

34 Lower arm element of U2 (arm element)

35 Lower arm element of V2 (arm element)

36 W2 lower arm element (arm element)

41. First battery (first power supply)

42. Second battery (second power supply)

50. Control device

Rg1 and Rg 2.

Detailed Description

Hereinafter, one embodiment of the motor drive system according to the present invention will be described in detail with reference to the drawings. The drawings are views as viewed from the direction of the reference numerals. In the following, the same components are denoted by the same reference numerals, and the description of overlapping contents is appropriately omitted.

< Motor drive System >

A motor drive system 1 of the present embodiment shown in fig. 1 is mounted on a vehicle (not shown) having wheels including drive wheels driven by power of a drive source. The Vehicle equipped with the motor drive system 1 (hereinafter, also simply referred to as a Vehicle) is, for example, an electric Vehicle (electric Vehicle) having a motor generator 10, which will be described later, provided in the motor drive system 1 as a drive source. The Vehicle may be a Hybrid electric Vehicle (Hybrid electric Vehicle) including an engine (not shown) in addition to the motor generator 10.

As shown in fig. 1, the motor drive system 1 includes a motor generator 10, a power conversion device 15, a first battery 41, a second battery 42, and a control device 50.

The motor generator 10 is an electric motor (so-called traction motor) that generates torque for driving a drive wheel of a vehicle, and is an example of a motor in the present invention. The motor generator 10 may also function as a generator that generates electric power by being driven by power transmitted from a drive wheel of the vehicle, an engine, or the like.

The motor generator 10 is a permanent magnet synchronous three-phase ac motor including a rotor (hereinafter, also referred to as a rotor) and a stator (hereinafter, also referred to as a stator), which are not shown. Specifically, the motor generator 10 may be, for example, an IPM (Interior Permanent Magnet) motor, but is not limited thereto, and may be a SPM (Surface Permanent Magnet) motor or the like.

The motor generator 10 includes a U-phase coil 11, a V-phase coil 12, and a W-phase coil 13 as stator windings (stator coils) included in a stator.

In this specification and the like, a current flowing through U-phase coil 11 is sometimes referred to as U-phase current Iu, a current flowing through V-phase coil 12 is sometimes referred to as V-phase current Iv, and a current flowing through W-phase coil 13 is sometimes referred to as W-phase current Iw. In this specification and the like, the direction in which the respective currents of the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw flow from the upper side (i.e., the first inverter 20 side) to the lower side (i.e., the second inverter 30 side) in fig. 1 is positive.

The motor generator 10 is provided with a resolver 14 that detects the rotation angle of the rotor. The resolver 14 is provided in a state in which communication with the control device 50 is possible, and outputs a detection signal indicating the detected rotation angle of the rotor to the control device 50.

The power conversion device 15 is a device that is controlled by the control device 50 and converts electric power supplied from at least one of the first battery 41 and the second battery 42 to the motor generator 10. Specifically, the power conversion device 15 converts the direct current power received from at least one of the first battery 41 and the second battery 42 into alternating current power, and supplies the alternating current power to the motor generator 10. The power conversion device 15 may convert the electric power supplied from the motor generator 10 to at least one of the first battery 41 and the second battery 42. In this case, the power conversion device 15 converts the alternating current power received from the motor generator 10 into direct current power and supplies it to at least one of the first battery 41 and the second battery 42.

The power conversion device 15 includes a first inverter 20 and a second inverter 30. The first inverter 20 is a three-phase inverter that switches energization of each coil of the dynamo-electric machine 10 such as the U-phase coil 11, the V-phase coil 12, and the W-phase coil 13.

Specifically, the first inverter 20 includes, as switching elements for switching the energization of the coils of the motor generator 10, a U1 upper arm element 21, a V1 upper arm element 22, a W1 upper arm element 23, a U1 lower arm element 24, a V1 lower arm element 25, and a W1 lower arm element 26. Each switching element of first inverter 20, such as U1 upper arm element 21, V1 upper arm element 22, W1 upper arm element 23, U1 lower arm element 24, V1 lower arm element 25, and W1 lower arm element 26, is, for example, a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

When each switching element of the first inverter 20 is a MOSFET, the source terminal of the U1 upper arm element 21 is connected to the drain terminal of the U1 lower arm element 24, the source terminal of the V1 upper arm element 22 is connected to the drain terminal of the V1 lower arm element 25, and the source terminal of the W1 upper arm element 23 is connected to the drain terminal of the W1 lower arm element 26. Furthermore, these switching elements have so-called anti-parallel diodes.

The switching elements of first inverter 20 are not limited to MOSFETs, but may be IGBTs (Insulated Gate Bipolar transistors) or the like. When each switching element of the first inverter 20 is an IGBT, the source is replaced with an emitter and the drain is replaced with a collector in the description of the first inverter 20.

The first inverter 20 includes a first connection terminal (not shown) for electrically connecting the inside and the outside of the first inverter 20. The first connection terminal of the first inverter 20 can function as an output unit of the first inverter 20. One ends 111, 121, 131 of the coils of the motor generator 10 are electrically connected to the inside of the first inverter 20 via the first connection terminal of the first inverter 20.

Specifically, one end 111 of the U-phase coil 11 is connected to a connection point 27 between the U1 upper arm element 21 and the U1 lower arm element 24 paired in the first inverter 20. Further, one end 121 of the V-phase coil 12 is connected to a connection point 28 of the V1 upper arm element 22 and the V1 lower arm element 25 paired in the first inverter 20. Further, one end 131 of the W-phase coil 13 is connected to a connection point 29 of the W1 upper arm element 23 and the W1 lower arm element 26 paired in the first inverter 20.

The first inverter 20 includes a second connection terminal (not shown) for electrically connecting the inside and the outside of the first inverter 20. The second connection terminal of the first inverter 20 can function as an input unit of the first inverter 20. The first battery 41 is electrically connected to the inside of the first inverter 20 via the second connection terminal of the first inverter 20.

Specifically, the positive electrode (positive terminal) of the first battery 41 is connected to the first high-potential-side wiring 46 connecting the drain terminals of the U1 upper arm element 21, the V1 upper arm element 22, and the W1 upper arm element 23 in the first inverter 20. In the first inverter 20, the negative electrode (negative terminal) of the first battery 41 is connected to a first low-potential-side wiring 47 that connects the source terminals of the U1 lower arm element 24, the V1 lower arm element 25, and the W1 lower arm element 26.

The first battery 41 is a dc power supply implemented by a chargeable and dischargeable secondary battery such as a lithium ion battery or a nickel hydride battery, for example. Further, the first battery 41 is provided with a first battery sensor 41a that detects the output, temperature, and the like of the first battery 41. The first battery sensor 41a is provided in a state in which it can communicate with the control device 50, and outputs a detection signal indicating the detected output, temperature, and the like of the first battery 41 to the control device 50.

Similarly to the first inverter 20, the second inverter 30 is also a three-phase inverter that switches energization of each coil of the dynamo-electric machine 10 such as the U-phase coil 11, the V-phase coil 12, and the W-phase coil 13.

Specifically, the second inverter 30 includes a U2 upper arm element 31, a V2 upper arm element 32, a W2 upper arm element 33, a U2 lower arm element 34, a V2 lower arm element 35, and a W2 lower arm element 36 as switching elements for switching energization of the respective coils of the motor generator 10. Each switching element of second inverter 30, such as U2 upper arm element 31, V2 upper arm element 32, W2 upper arm element 33, U2 lower arm element 34, V2 lower arm element 35, and W2 lower arm element 36, is a MOSFET, for example.

When each switching element of the second inverter 30 is a MOSFET, the source terminal of the U2 upper arm element 31 is connected to the drain terminal of the U2 lower arm element 34, the source terminal of the V2 upper arm element 32 is connected to the drain terminal of the V2 lower arm element 35, and the source terminal of the W2 upper arm element 33 is connected to the drain terminal of the W2 lower arm element 36. Furthermore, these switching elements have so-called anti-parallel diodes.

The switching elements of the second inverter 30 are not limited to MOSFETs, and may be IGBTs or the like. When each switching element of second inverter 30 is an IGBT, the source and the drain in the description of second inverter 30 are emitter and collector, respectively.

The second inverter 30 includes a first connection terminal (not shown) for electrically connecting the inside and the outside of the second inverter 30. The first connection terminal of the second inverter 30 can function as an output unit of the second inverter 30. The other ends 112, 122, 132 of the coils of the motor generator 10 are electrically connected to the inside of the second inverter 30 via the first connection terminal of the second inverter 30.

Specifically, the other end 112 of the U-phase coil 11 is connected to a connection point 37 between the U2 upper arm element 31 and the U2 lower arm element 34 paired in the second inverter 30. Further, the other end 122 of the V-phase coil 12 is connected to a connection point 38 of the V2 upper arm element 32 and the V2 lower arm element 35 paired in the second inverter 30. Further, the other end 132 of the W-phase coil 13 is connected to a connection point 39 of the W2 upper arm element 33 and the W2 lower arm element 36 paired in the second inverter 30.

The second inverter 30 includes a second connection terminal (not shown) for electrically connecting the inside and the outside of the second inverter 30. The second connection terminal of the second inverter 30 can function as an input unit of the second inverter 30. The second battery 42 is electrically connected to the inside of the second inverter 30 via a second connection terminal of the second inverter 30.

Specifically, the positive electrode (positive terminal) of the second battery 42 is connected to the second high-potential-side wiring 48 connecting the drain terminals of the U2 upper arm element 31, the V2 upper arm element 32, and the W2 upper arm element 33 in the second inverter 30. Further, the negative electrode (negative terminal) of the second battery 42 is connected to a second low-potential-side wiring 49 connecting the source terminals of the U2 lower arm element 34, the V2 lower arm element 35, and the W2 lower arm element 36 in the second inverter 30.

The second battery 42 is a dc power supply implemented by a chargeable and dischargeable secondary battery such as a lithium ion battery or a nickel metal hydride battery. Further, the second battery 42 is provided with a second battery sensor 42a that detects the output, temperature, and the like of the second battery 42. The second battery sensor 42a is provided in a state in which it can communicate with the control device 50, and outputs a detection signal indicating the detected output, temperature, and the like of the second battery 42 to the control device 50.

The control device 50 is a device that controls the motor drive system 1, and for example, controls the entire vehicle. For example, the control device 50 is configured to include a processor (not shown) capable of executing various operations, a RAM (Random Access Memory) serving as a work area of the processor, and a storage medium such as a ROM (Read Only Memory) storing various information. Further, control device 50 has an inverter control unit 51 that controls first inverter 20 and second inverter 30, and an abnormality detection unit 52 that detects an abnormality of first inverter 20 and second inverter 30, as functional units realized by a processor executing a program stored in a storage medium such as a ROM.

The inverter control unit 51 controls the first inverter 20 by controlling the operation (on and off) of each switching element of the first inverter 20, such as the U1 upper arm element 21, the V1 upper arm element 22, the W1 upper arm element 23, the U1 lower arm element 24, the V1 lower arm element 25, and the W1 lower arm element 26. Inverter control unit 51 controls second inverter 30 by controlling the operation of each switching element of second inverter 30, such as U2 upper arm element 31, V2 upper arm element 32, W2 upper arm element 33, U2 lower arm element 34, V2 lower arm element 35, and W2 lower arm element 36.

For example, inverter control unit 51 generates control signals for controlling the operation of each switching element of first inverter 20 and second inverter 30. Then, inverter control unit 51 outputs the generated control signal to a drive circuit (not shown) connected to each switching element of first inverter 20 and second inverter 30. This enables control of the operation of each switching element of the first inverter 20 and the second inverter 30.

Abnormality detection unit 52 is configured to be able to detect a failure of each switching element of first inverter 20 and second inverter 30 as an abnormality of first inverter 20 and second inverter 30. Examples of the types of failure of the switching element include an open failure in which the switching element cannot be turned on and a short failure in which the switching element cannot be turned off. Here, the failure of the switching element includes a failure due to a failure of the switching element itself, and also a failure due to a signal abnormality from the control device 50, a failure of a drive circuit connected to each switching element of the first inverter 20 and the second inverter 30, or the like. In addition, any method may be used for detecting a failure of the switching element by the abnormality detecting unit 52. For example, a failure of the switching element can be detected by using a measurement result of a current sensor (not shown) that measures a current (motor current) flowing through the motor generator 10, in addition to a protection function such as short-circuit detection and temperature monitoring for the switching element.

< control example of Motor drive System by control device >

Next, a specific control example of the motor drive system 1 by the control device 50 will be described. First, an example will be described in which the abnormality detection unit 52 does not detect a failure of the switching elements of the first inverter 20 and the second inverter 30, that is, in which both the first inverter 20 and the second inverter 30 are normal.

< Normal mode >

When the abnormality detection unit 52 does not detect a failure of the switching elements of the first inverter 20 and the second inverter 30, the control device 50 controls the motor drive system 1 in the normal mode. Here, the normal mode is a control mode in which the electric power of both the first battery 41 and the second battery 42 can be used to drive the motor generator 10.

That is, in the normal mode, the control device 50 can control the first inverter 20 to supply the electric power of the first battery 41 to the motor generator 10 to drive the motor generator 10 (i.e., to run the vehicle), and can also control the second inverter 30 to supply the electric power of the second battery 42 to the motor generator 10 to drive the motor generator 10.

For example, in the normal mode, when the driving force required to run the vehicle (hereinafter also referred to as the required driving force) is relatively small, the control device 50 supplies the electric power of one of the first battery 41 and the second battery 42 to the motor generator 10. On the other hand, in the normal mode and when the required driving force is large, the control device 50 supplies the electric power of both the first battery 41 and the second battery 42 to the motor generator 10. Thereby, the electric power corresponding to the required driving force is supplied to the motor generator 10, and the motor generator 10 can generate the torque corresponding to the required driving force. In other words, the required driving force can be ensured by the torque generated by the motor generator 10.

Further, the control device 50 can supply only the electric power of the first battery 41 to the motor generator 10 by setting the second inverter 30 to the neutral point. In order to set second inverter 30 to the neutral point, U2 upper arm element 31, V2 upper arm element 32, and W2 upper arm element 33 may be turned on, and U2 lower arm element 34, V2 lower arm element 35, and W2 lower arm element 36 may be turned off, for example. Further, the second inverter 30 can be set to the neutral point by turning off the U2 upper arm element 31, the V2 upper arm element 32, and the W2 upper arm element 33 and turning on the U2 lower arm element 34, the V2 lower arm element 35, and the W2 lower arm element 36.

Further, the control device 50 can supply only the electric power of the second battery 42 to the motor generator 10 by setting the first inverter 20 to the neutral point. In order to set the first inverter 20 to the neutral point, for example, the U1 upper arm element 21, the V1 upper arm element 22, and the W1 upper arm element 23 may be turned on, and the U1 lower arm element 24, the V1 lower arm element 25, and the W1 lower arm element 26 may be turned off. Further, the first inverter 20 can be set to the neutral point by turning off the U1 upper arm element 21, the V1 upper arm element 22, and the W1 upper arm element 23 and turning on the U1 lower arm element 24, the V1 lower arm element 25, and the W1 lower arm element 26.

Further, the control device 50 can supply the electric power of both the first battery 41 and the second battery 42 to the motor generator 10 by, for example, controlling the switching elements of the first inverter 20 and the switching elements of the second inverter 30 corresponding to the switching elements by inverting the phases thereof.

< failure mode >

Next, an example will be described in which the abnormality detection unit 52 detects a failure of any switching element of the first inverter 20 and the second inverter 30, that is, in a case where an abnormality occurs in the first inverter 20 or the second inverter 30.

When the abnormality detection unit 52 detects a failure of any switching element in the first inverter 20 and the second inverter 30, the control device 50 controls the motor drive system 1 in a failure mode. Here, the failure mode is a control mode in which only the electric power of the battery in which abnormality has not occurred (i.e., the normal battery) of the first battery 41 and the second battery 42 can be used to drive the motor generator 10.

That is, for example, an abnormality occurs in the first inverter 20 due to a failure of any switching element of the first inverter 20, and the normal mode is switched to the failure mode. In this case, after shifting to the failure mode, control device 50 sets first inverter 20 to the neutral point, and drives motor generator 10 only with the electric power of second battery 42.

Further, for example, an abnormality occurs in second inverter 30 due to a failure of any switching element of second inverter 30, and the mode is switched from the normal mode to the failure mode. In this case, after shifting to the failure mode, controller 50 sets second inverter 30 to the neutral point, and drives motor generator 10 only with the electric power of first battery 41.

For example, when short-circuit failure occurs in any of

upper arm elements

31, 32, and 33 of second inverter 30 or when open-circuit failure occurs in any of

lower arm elements

34, 35, and 36 of second inverter 30, controller 50 brings the three

upper arm elements

31, 32, and 33 of second inverter 30 into a conductive state (i.e., an on state), thereby bringing second inverter 30 to the neutral point. On the other hand, when short-circuit failure occurs in any of

lower arm elements

34, 35, 36 of second inverter 30 or when open-circuit failure occurs in any of

upper arm elements

31, 32, 33 of second inverter 30, controller 50 brings the three

lower arm elements

34, 35, 36 of second inverter 30 into a conductive state, thereby bringing second inverter 30 into a neutral point.

In addition, from the viewpoint of effectively utilizing the power of the battery connected to the inverter in which the abnormality has occurred, when the failure mode is set, the control device 50 may sometimes perform power transmission (hereinafter, also simply referred to as power transmission) from the battery connected to the inverter in which the abnormality has occurred to the battery connected to the inverter in which the abnormality has not occurred. For example, if an abnormality occurs in first inverter 20, control device 50 performs power transmission from first battery 41 to second battery 42, and if an abnormality occurs in second inverter 30, control device 50 performs power transmission from second battery 42 to first battery 41.

By performing such power transmission by the control device 50, it is possible to effectively use the power of the battery connected to the inverter in which the abnormality has occurred. As a result, the cruising distance of the vehicle can be extended by the electric power of the first battery 41 and the second battery 42 as compared with the case where the electric power transmission is not performed.

< specific control example of switching elements in power transmission >

Next, a specific control example of the switching elements of the first inverter 20 and the second inverter 30 when the control device 50 transmits electric power will be described. Hereinafter, a phase in which no abnormality occurs is also referred to as a normal phase. In addition, a phase in which an abnormality occurs is also referred to as an abnormal phase.

The control device 50 varies the operation of the switching elements of the first inverter 20 and the second inverter 30 during power transmission according to the switching element in which the failure has occurred and the type of failure of the switching element.

< first example >

First, a first example of a case where an open failure occurs in any upper arm element of the first inverter 20 will be described with reference to fig. 2. Here, a case where an open failure has occurred in the upper arm element 23 of W1 of the first inverter 20 will be described as an example.

In fig. 2 to 5, the motor generator 10, the first inverter 20, the second inverter 30, the first battery 41, and the second battery 42 among the components of the motor drive system 1 shown in fig. 1 are illustrated, and other configurations such as the resolver 14, the first battery sensor 41a, the second battery sensor 42a, and the control device 50 are not illustrated.

As shown in fig. 2 (a), it is assumed that an open fault has occurred in the upper arm element 23 of W1 of the first inverter 20. In this case, when power transmission is performed, the control device 50 turns on the W1 lower arm element 26 that is paired with the failed W1 upper arm element 23. As a result, W1 upper arm element 23, which is the upper arm element of the first inverter 20 in the W phase, which is the abnormal phase, is turned off, and W1 lower arm element 26, which is the lower arm element that is the paired upper arm element, is turned on.

Further, control device 50 turns off upper arm element W2 of upper arm element 33 of second inverter 30 in W phase, which is the abnormal phase, and turns on lower arm element W2 of lower arm element 36 which is a pair thereof. Thus, in both the first inverter 20 and the second inverter 30, the upper arm elements are turned off and the lower arm elements are turned on in the W phase, which is an abnormal phase.

Fig. 2 (b) shows an equivalent circuit in the case where W1 upper arm element 23 and W2 upper arm element 33 are turned off and W1 lower arm element 26 and W2 lower arm element 36 are turned on. That is, in this case, control device 50 can transmit the electric power of first battery 41 to second battery 42 by motor generator 10, first inverter 20, and second inverter 30 as indicated by arrows of

reference numerals

201 and 202 in fig. 2 (b) by controlling the switching element of the normal phase as a chopper (DC/DC converter) (in other words, the normal phase is a phase that performs switching).

Note that, although the case where the open failure has occurred in the W1 upper arm element 23 is described here as an example, the same applies to the case where the open failure has occurred in the other upper arm elements in the first inverter 20 such as the U1 upper arm element 21 and the V1 upper arm element 22, or in any of the

upper arm elements

31, 32, and 33 in the second inverter 30. That is, the lower arm element paired with the upper arm element having the open-circuit failure may be turned on, and the upper arm element of the other inverter in the abnormal phase may be turned off and the lower arm element paired with the upper arm element may be turned on.

< second example >

Next, a second example of a case where a short-circuit fault occurs in any lower arm element in the first inverter 20 will be described with reference to fig. 3. Here, a case where the short-circuit failure occurs in the W1 lower arm element 26 of the first inverter 20 will be described as an example.

As shown in fig. 3 (a), it is assumed that the short-circuit fault has occurred in the W1 lower arm element 26 of the first inverter 20. In this case, when power transmission is performed, the control device 50 disconnects the W1 upper arm element 23 paired with the failed W1 lower arm element 26. Thus, in this case as well, in the same manner as the example shown in fig. 2 (a), the W1 upper arm element 23, which is the upper arm element of the first inverter 20 in the W phase, which is the abnormal phase, is turned off, and the W1 lower arm element 26, which is the lower arm element paired with the abnormal phase, is turned on. Therefore, also in this case, as in the example shown in fig. 2 (a), the control device 50 turns off the W2 upper arm element 33 as the upper arm element of the second inverter 30 in the W phase as the abnormal phase, and turns on the W2 lower arm element 36 as the lower arm element paired therewith.

As a result, as shown in fig. 3 (b), the equivalent circuit similar to that of fig. 2 (b) can be obtained. Therefore, control device 50 can transmit the electric power of first battery 41 to second battery 42 by motor generator 10, first inverter 20, and second inverter 30 as indicated by arrows of

reference numerals

301 and 302 in (b) of fig. 3 by controlling the switching elements of the normal phase as a chopper.

Note that, although the case where the short-circuit failure occurs in the W1 lower arm element 26 is described here as an example, the same applies to the case where the short-circuit failure occurs in the other lower arm elements in the first inverter 20, such as the U1 lower arm element 24 and the V1 lower arm element 25, or in any of the

lower arm elements

34, 35, and 36 in the second inverter 30. That is, the upper arm element that is paired with the lower arm element in which the short-circuit fault has occurred may be turned off, and the upper arm element of the other inverter in the abnormal phase may be turned off, and the lower arm element that is paired with the upper arm element may be turned on.

< third example >

Next, a third example of a case where a short-circuit failure occurs in any upper arm element of the first inverter 20 will be described with reference to fig. 4. Here, a case where the upper arm element 23 of W1 of the first inverter 20 has a short-circuit fault will be described as an example.

As shown in fig. 4 (a), it is assumed that the upper arm element 23 of W1 of the first inverter 20 has a short-circuit fault. In this case, when power transmission is performed, the control device 50 disconnects the W1 lower arm element 26 paired with the failed W1 upper arm element 23. As a result, the W1 upper arm element 23, which is the upper arm element of the first inverter 20 in the W phase, which is the abnormal phase, is turned on, and the W1 lower arm element 26, which is the lower arm element paired with the upper arm element, is turned off.

Further, control device 50 turns on upper arm element W2 of upper arm element 33 of second inverter 30 in W phase, which is the abnormal phase, and turns off lower arm element W2 of lower arm element 36, which is the paired one. Thus, in both the first inverter 20 and the second inverter 30, the upper arm element is turned on and the lower arm element is turned off in the W phase, which is an abnormal phase.

Fig. 4 (b) shows an equivalent circuit in the case where W1 upper arm element 23 and W2 upper arm element 33 are turned on and W1 lower arm element 26 and W2 lower arm element 36 are turned off. That is, in this case as well, control device 50 controls the switching element of the normal phase to be a chopper (DC/DC converter), and thereby can transmit the electric power of first battery 41 to second battery 42 by motor generator 10, first inverter 20, and second inverter 30 as indicated by arrows denoted by

reference numerals

401 and 402 in fig. 4 (b).

Note that, although the case where the W1 upper arm element 23 has a short-circuit failure has been described here as an example, the same applies to the case where another upper arm element in the first inverter 20, such as the U1 upper arm element 21 and the V1 upper arm element 22, or any of the

upper arm elements

31, 32, and 33 in the second inverter 30 has a short-circuit failure. That is, the lower arm element paired with the upper arm element in which the short-circuit failure has occurred may be turned off, and the upper arm element of the other inverter in the abnormal phase may be turned on and the lower arm element paired therewith may be turned off.

Note that, in the case where the abnormal phase is stuck to the high potential side as shown in fig. 2 and the like and in the case where the abnormal phase is stuck to the high potential side as shown in fig. 4 and the like, the direction of the current flowing through the coil of the motor generator 10 at the time of power transmission changes.

< fourth example >

Next, a fourth example, which is an example in the case where an open failure occurs in any lower arm element in the first inverter 20, will be described with reference to fig. 5. Here, a case where the open failure occurs in the W1 lower arm element 26 of the first inverter 20 will be described as an example.

As shown in fig. 5 (a), it is assumed that the open failure has occurred in the W1 lower arm element 26 of the first inverter 20. In this case, when power transmission is performed, the control device 50 turns on the W1 upper arm element 23 that is paired with the failed W1 lower arm element 26. Thus, in this case as well, in the same manner as the example shown in fig. 4 (a), the W1 upper arm element 23, which is the upper arm element of the first inverter 20 in the W phase, which is the abnormal phase, is turned on, and the W1 lower arm element 26, which is the lower arm element paired with the abnormal phase, is turned off. Therefore, in this case as well, as in the example shown in fig. 4 (a), the control device 50 turns on the W2 upper arm element 33, which is the upper arm element of the second inverter 30 in the W phase, which is the abnormal phase, and turns off the W2 lower arm element 36, which is the lower arm element that is the pair thereof.

As a result, as shown in fig. 5 (b), the equivalent circuit similar to that of fig. 4 (b) can be obtained. Therefore, control device 50 can transmit the electric power of first battery 41 to second battery 42 by motor generator 10, first inverter 20, and second inverter 30 as indicated by arrows of

reference numerals

501 and 502 in (b) of fig. 5 by controlling the switching elements of the normal phase as a chopper.

Note that, although the case where the open failure occurs in the W1 lower arm element 26 is described here as an example, the same applies to the case where the open failure occurs in the other lower arm elements in the first inverter 20, such as the U1 lower arm element 24 and the V1 lower arm element 25, or in any of the

lower arm elements

34, 35, and 36 in the second inverter 30. That is, the upper arm element paired with the lower arm element in which the open-circuit fault has occurred may be turned on, the upper arm element of the other inverter in the abnormal phase may be turned on, and the lower arm element paired with the upper arm element may be turned off.

As described above, the control device 50 can perform power transmission without providing a separate dedicated circuit for power transmission in the motor drive system 1, and can effectively use the power of the battery connected to the inverter in which the abnormality has occurred with a simple configuration. Therefore, when an abnormality occurs in first inverter 20 or second inverter 30, the cruising distance of the vehicle using the electric power of first battery 41 and second battery 42 can be extended.

< Current control during Power Transmission >

In addition, in the motor drive system 1, a current flows through the motor generator 10 at the time of power transmission. Therefore, if the current flowing through the motor generator 10 due to the electric power transmission is not appropriately controlled, the motor generator 10 may generate torque due to the current. It is assumed that when the motor generator 10 generates torque due to power transmission, the motor generator 10 is sometimes driven against the user's will (e.g., the vehicle is moving), and thus the merchantability of the motor drive system 1 may be degraded. Therefore, from the viewpoint of ensuring the merchantability of the motor drive system 1, it is desirable to transmit electric power without causing the motor generator 10 to generate torque.

Hereinafter, the current flowing through each coil of the motor generator 10 in the direction of charging from the first battery 41 to the second battery 42 due to the power transmission in each failure state is also referred to as a second battery charging direction current.

In order to avoid the generation of torque by the motor generator 10 due to the power transmission, the control device 50 performs the power transmission when the driving of the motor generator 10 is stopped (for example, the vehicle is stopped), and controls the respective currents so that the resultant current vector of the second battery charging direction currents flowing through the normal phase is directed toward the d-axis direction (magnetic flux direction) of the rotor at the time of the power transmission.

As shown in fig. 6, for example, the normal direction of the d-axis of the rotor is a direction included in the angular range Rg1, and the normal phases are the U-phase and the V-phase, whereby electric power is transmitted from the first battery 41 to the second battery 42. Here, the angular range Rg1 is an angular range of vectors that can be synthesized from current vectors of the second battery charging direction currents flowing through the U-phase and the V-phase, which are normal phases (i.e., an angular range on a vector diagram), and is a range in which both the U-phase current Iu and the V-phase current Iv are positive.

In the case of the example shown in fig. 6, control device 50 controls the current value of U-phase current Iu flowing through U-phase coil 11 by power transmission to be Iu _ a (where Iu _ a is not greater than the maximum value Iu _ max that U-phase current Iu can take). Further, the control device 50 controls so that the current value of the V-phase current Iv flowing to the V-phase coil 12 due to power transmission is Iv _ a (where Iv _ a ≦ the maximum value Iv _ max that the V-phase current Iv can take). Thus, the direction of the combined current vector I _ a obtained by combining the U-phase current Iu and the V-phase current Iv by power transmission can be made the same as the positive direction of the d-axis of the rotor. Therefore, the motor generator 10 can transmit electric power without generating torque.

As shown in fig. 7, the controller 50 may also perform power transmission from the first battery 41 to the second battery 42 when the positive d-axis direction of the rotor is in a direction included in the angular range Rg 2. Here, the angular range Rg2 is an angular range of vectors which can be synthesized from current vectors of the second battery charging direction currents flowing through the U-phase and the V-phase, which are normal phases, and is a range in which both the U-phase current Iu and the V-phase current Iv are negative.

In the case of the example shown in fig. 7, control device 50 controls the current value of U-phase current Iu flowing through U-phase coil 11 by power transmission to be Iu _ b (where Iu _ b is equal to or less than Iu _ max). Further, the control device 50 controls the current value of the V-phase current Iv flowing to the V-phase coil 12 due to power transmission to be Iv _ b (where Iv _ b ≦ Iv _ max). This makes it possible to set the direction of the combined current vector I _ B obtained by combining the U-phase current Iu and the V-phase current Iv by power transmission to the same direction as the negative direction of the d-axis of the rotor. Therefore, the motor generator 10 can transmit electric power without generating torque.

However, as shown in fig. 7, when the resultant current vector of the second battery charging direction current flowing through the normal phase due to the power transmission is directed in the d-axis negative direction of the rotor, it is desirable to reduce the current value of the current flowing due to the power transmission to some extent from the viewpoint of suppressing irreversible demagnetization (hereinafter, also simply referred to as irreversible demagnetization) of the permanent magnet included in the rotor.

On the other hand, as shown in fig. 6, when the resultant current vector of the second battery charging direction current flowing through the normal phase due to the power transmission is oriented in the positive direction of the d-axis of the rotor, irreversible demagnetization does not occur even if the current value of the current flowing due to the power transmission is increased. Therefore, when the combined current vector of the second battery charging direction current flowing through the normal phase is directed toward the positive direction of the d-axis of the rotor due to power transmission, the current value of the flowing current can be increased, and power transmission with good time efficiency can be performed.

In this way, when the d-axis direction of the rotor is included in the angular range of the vector that can be synthesized from the current vectors of the second battery charging direction currents flowing through the normal phase, the direction of the synthesized current vector of the second battery charging direction currents flowing through the normal phase due to the power transmission can be matched with the d-axis direction of the rotor, and therefore the power transmission can be performed without generating torque in the motor generator 10.

In contrast, when the d-axis direction of the rotor is not included in the angular range of the vector that can be synthesized from the current vectors of the second battery charging direction currents flowing through the normal phase, the direction of the synthesized current vector of the second battery charging direction currents flowing through the normal phase due to power transmission cannot be matched with the d-axis direction of the rotor. Therefore, in this case, it is impossible to transmit electric power without generating torque by the motor generator 10.

Therefore, the control device 50 performs power transmission only when the d-axis direction of the rotor is included in the angular range of the vector that can be synthesized from the current vector of the second battery charging direction current flowing through the normal phase. Thereby, the generation of torque by the motor generator 10 due to the power transmission can be avoided.

Further, the controller 50 can derive (in other words, acquire) the d-axis direction of the rotor based on, for example, the rotation angle of the rotor indicated by the detection signal received from the resolver 14.

Further, control device 50 may transmit power on the condition that the remaining capacity (SOC) Of the battery connected to the inverter in which the abnormality has occurred is equal to or greater than a predetermined value (for example, X% described later). In this way, it is possible to avoid performing power transmission when only a small amount of power can be transmitted even if power transmission is performed because the remaining capacity of the battery connected to the inverter in which the abnormality has occurred is small. Therefore, deterioration of the first battery 41 and the second battery 42 due to charge and discharge of the batteries by power transmission capable of transmitting only minute electric power is suppressed, thereby protecting these batteries.

The control device 50 may transmit power on the condition that the remaining capacity of the battery connected to the inverter in which no abnormality occurs is less than a predetermined value (for example, Y%) or less. In this way, it is possible to avoid a situation in which power transmission is performed despite sufficient power being stored in the battery connected to the inverter in which no abnormality has occurred. Therefore, deterioration of the first battery 41 and the second battery 42 due to charge and discharge by power transmission with low necessity is suppressed, thereby protecting these batteries. In addition, in this way, power transmission can be performed before the electric power of the battery connected to the inverter in which no abnormality has occurred is exhausted and the motor generator 10 cannot be driven by the electric power of the battery.

Further, the control device 50 can derive (in other words, acquire) the remaining capacity of the first battery 41 based on, for example, the output of the first battery 41 indicated by the detection signal received from the first battery sensor 41a. Similarly, the control device 50 can derive the remaining capacity of the second battery 42, for example, based on the output of the second battery 42 indicated by the detection signal received from the second battery sensor 42a.

< control processing by control device >

Next, an example of the control process of the motor drive system 1 performed by the control device 50 will be described. For example, when the ignition power source of the vehicle is turned on, the control device 50 executes the control processing described below at a predetermined cycle.

As shown in fig. 8, control device 50 determines whether or not a failure of the switching elements of first inverter 20 and second inverter 30 is detected (step S1). If the switching elements of the first inverter 20 and the second inverter 30 are not malfunctioning (step S1: no), the control device 50 controls the motor drive system 1 in the normal mode (step S2), and the series of processing shown in fig. 8 is ended.

On the other hand, when a failure occurs in the switching elements of first inverter 20 or second inverter 30 (step S1: yes), control device 50 shifts from the normal mode to the failure mode (step S3).

Then, the control device 50 determines whether or not to continue driving of the motor generator 10 (step S4). In step S4, for example, if there is no drive stop request to stop the drive of the motor generator 10, the control device 50 determines to continue the drive of the motor generator 10. On the other hand, if there is a drive stop request, the control device 50 determines that the drive of the motor generator 10 is not to be continued (i.e., stopped). The drive stop request includes, for example, an accelerator-off request in which an accelerator pedal of the vehicle is not operated, and a brake-on request in which a brake pedal of the vehicle is operated.

When the driving of the motor generator 10 is continued (yes in step S4), the control device 50 sets the inverter having the abnormality to the neutral point, drives the motor generator 10 only by the electric power of the battery connected to the inverter having no abnormality (step S5), and returns to the processing of step S4.

When stopping the motor generator 10 (no in step S4), the control device 50 controls the motor generator 10 to stop in a state where the d-axis positive direction of the rotor is included in a predetermined angle range corresponding to the normal state (step S6). Here, as described above, the predetermined angular range is a vector angular range that can be synthesized from the current vector of the second battery charging direction current flowing through the normal phase.

In this way, the control device 50 controls the motor generator 10 to stop in a state where the positive d-axis direction of the rotor is included in the predetermined angular range corresponding to the normal state in response to the drive stop request, and thereby the opportunity of being able to perform power transmission can be increased.

Then, the control device 50 waits for the stop of the motor generator 10 (no in step S7), and when the motor generator 10 stops (yes in step S7), confirms whether the d-axis positive direction of the rotor is included in the predetermined angle range (step S8). If the positive d-axis direction of the rotor is not included in the predetermined angular range for some reason (no in step S8), the control device 50 ends the series of processing shown in fig. 8. This can avoid power transmission that may cause the motor generator 10 to generate torque.

On the other hand, when the positive d-axis direction of the rotor is included in the predetermined angular range (yes in step S8), the control device 50 determines whether or not the first SOC, which is the remaining capacity of the battery connected to the inverter in which the abnormality has occurred, is X% (e.g., 10%) or more (step S9). Here, X% is set in advance in the control device 50 by a manufacturer of the motor drive system 1 or the like.

If the first SOC is less than X% (no in step S9), control device 50 ends the series of processing shown in fig. 8. This makes it possible to avoid power transmission that can transmit only a small amount of power, and to avoid deterioration of the first battery 41 and the second battery 42 due to charging and discharging of the power transmission.

On the other hand, if the first SOC is X% or more (yes in step S9), the control device 50 determines whether or not the second SOC, which is the remaining capacity (for example, the remaining capacity at the current time) of the battery connected to the inverter in which no abnormality has occurred, is less than Y% (for example, 10%) (step S10). Here, Y% is set in advance in the control device 50 by the manufacturer of the motor drive system 1 or the like.

When the second SOC is equal to or greater than Y% (no in step S10), control device 50 ends the series of processing shown in fig. 8. This makes it possible to avoid power transmission even if sufficient power is stored in the battery connected to the inverter in which no abnormality has occurred, and to avoid deterioration of the first battery 41 and the second battery 42 due to charging and discharging of the battery by the power transmission.

On the other hand, if the second SOC is less than Y% (step S10: yes), control device 50 executes power transmission using the normal phase of motor generator 10, first inverter 20, and second inverter 30 (step S11), and then ends the series of processing shown in fig. 8.

In step S10, control device 50 may determine whether or not the second SOC is less than Y% when the estimated power consumption until the vehicle reaches the destination is subtracted from the power stored at the current time point in the battery connected to the inverter in which no abnormality has occurred. In this way, in addition to the estimated power consumption until the vehicle reaches the destination, a certain amount of surplus power can be secured in the battery connected to the inverter in which no abnormality has occurred, and the reliability that the vehicle can reach the destination using the power of the battery connected to the inverter in which no abnormality has occurred can be improved.

Further, when a failure occurs in a portion other than the switching elements in the motor drive system 1, the control device 50 may stop the motor generator 10 (i.e., the vehicle) at that point in time. Specifically, for example, when the switching element of the first inverter 20 or the second inverter 30 has failed (yes in step S1), the controller 50 then determines whether or not all the portions other than the failed phase are normal. The term "all" as used herein includes not only the switching elements of the first inverter 20 and the second inverter 30, but also the first battery 41, the second battery 42, the motor generator 10, and the like. Then, when it is determined that all the portions other than the failure phase are normal, the control device 50 proceeds to the processing of step S3. On the other hand, if it is determined that there is an abnormality that makes it difficult to continue the operation of the motor drive system 1 in a location other than the failed phase, the control device 50 stops the motor generator 10 (i.e., the vehicle) at that point in time. In this way, it is possible to avoid driving the motor generator 10 in a situation where a failure occurs in a portion other than the switching element in the motor drive system 1. The failure of each part other than the switching element can be appropriately detected by a detection means such as a sensor provided in each part, for example.

Further, when switching to the failure mode, the control device 50 may issue a predetermined notification to the user through a predetermined notification device such as a display or a speaker provided in the vehicle. Examples of the notification content at this time include: to failure mode (i.e., not normal); the motor generator 10 cannot be driven at full power; with the angular adjustment of the rotor for power transmission, there is a possibility that the stop position of the vehicle may deviate from the feeling of the user who performs braking; even if the second SOC (the remaining capacity of the battery connected to the inverter in which no abnormality has occurred) is reduced and the motor generator 10 cannot be driven, if the vehicle is stopped and stands by, there is a possibility that the motor generator 10 can be driven again (this is because the electric power of the battery connected to the inverter in which an abnormality has occurred can be transmitted to another battery), and the like.

As described above, according to the motor drive system 1 of the present embodiment, it is possible to appropriately transmit electric power from the battery connected to the inverter in which an abnormality has occurred, out of the first inverter 20 and the second inverter 30, to the battery connected to the inverter in which no abnormality has occurred, with a simple configuration.

The present invention is not limited to the above embodiments, and modifications, improvements, and the like can be appropriately made.

For example, in the above embodiment, the motor generator 10, the first inverter 20, and the second inverter 30 are three-phase, but they may be four-phase or more. That is, the present invention can also be applied to a motor drive system including four or more phase motors and inverters.

In the present specification, at least the following matters are described. Although the components and the like according to the above-described embodiment are shown in parentheses, the present invention is not limited to these.

(1) A motor drive system (motor drive system 1) is provided with:

a first inverter (first inverter 20) including a plurality of arm elements (U1 upper arm element 21, V1 upper arm element 22, W1 upper arm element 23, U1 lower arm element 24, V1 lower arm element 25, W1 lower arm element 26);

a second inverter (second inverter 30) including a plurality of arm elements (U2 upper arm element 31, V2 upper arm element 32, W2 upper arm element 33, U2 lower arm element 34, V2 lower arm element 35, W2 lower arm element 36);

a motor (motor generator 10) having one end (one

end

111, 121, 131) of a stator winding (U-phase coil 11, V-phase coil 12, W-phase coil 13) connected to an output unit of the first inverter and the other end (the

other end

112, 122, 132) of the stator winding connected to an output unit of the second inverter;

a first power supply (a first battery 41) connected to an input portion of the first inverter;

a second power supply (second battery 42) connected to an input of the second inverter; and

a control device (control device 50) capable of controlling the first inverter and the second inverter, wherein,

the control device performs the power transmission when a positive direction of a d-axis of a rotating member of the motor is included in a predetermined angular range (angular ranges Rg1, rg 2) corresponding to the normal state when the driving of the motor is stopped.

According to (1), it is possible to appropriately perform power transmission from the first power supply connected to the inverter in which the abnormality has occurred to the second power supply connected to the inverter in which the abnormality has not occurred with a simple configuration.

(2) The motor drive system according to (1), wherein,

when there is a drive stop request for stopping the drive of the motor in a state where any arm element of the first inverter has failed, the control device stops the drive of the motor so that the positive direction of the d-axis of the rotating element is included in the angular range.

According to (2), the chance that power transmission can be performed can be increased.

(3) The motor drive system according to (1) or (2), wherein,

the angular range is an angular range of vectors that can be synthesized from current vectors in a direction of charging the second power supply based on the normal phase.

According to (3), the generation of torque by the motor due to the power transmission can be avoided.

(4) The motor drive system according to any one of (1) to (3), wherein,

the first power source is a secondary battery capable of charging and discharging,

the control device performs the power transmission when a remaining capacity of the first power source is equal to or greater than a predetermined value.

According to (4), deterioration of the first power supply due to discharge of the first power supply by power transmission capable of transmitting only minute power is suppressed, thereby protecting the first power supply.

(5) The motor drive system according to any one of (1) to (4), wherein,

the second power source is a secondary battery capable of charging and discharging,

the control device performs the power transmission when the remaining capacity of the second power supply is less than a predetermined value.

According to (5), the deterioration of the second power supply due to the charging by the power transmission of which necessity is low is suppressed, thereby protecting the second power supply.

Claims

1. A motor drive system is provided with:

a first inverter including a plurality of arm elements;

a second inverter including a plurality of arm elements;

a first power supply connected to an input of the first inverter;

a second power supply connected to an input of the second inverter; and

2. The motor drive system of claim 1,

3. The motor drive system according to claim 1 or 2, wherein,

the angular range is an angular range of vectors that can be synthesized by current vectors in a direction of charging the second power supply based on the normal phase.

4. The motor drive system according to claim 1 or 2, wherein,

5. The motor drive system according to claim 1 or 2, wherein,