Drive device

Abstract

To increase a heat generation amount.SOLUTION: A drive device includes a power storage device, a motor having a three-phase coil, a first inverter connected to a power line to which the power storage device is connected and having a plurality of first switching elements connected to one end side of the three-phase coil, a second inverter connected to a power line to which the power line is connected and having a plurality of second switching elements connected to the other end side of the three-phase coil, a cooling device that cools the power storage device, the motor, and the first and second inverters using a cooling medium, and a control device that controls the first and second inverters based on a torque command of the motor. The control device controls the first and second inverters such that all phase currents of three phases of the three-phase coil of the motor circulate to the three phases from one of the first and second inverters via the power lines and the other of the first and second inverters.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a drive device. [Background technology]

[0002] Conventionally, a driving device of this type has been proposed that includes a motor (electric motor), an inverter, and a hydraulic mechanism (see, for example, Patent Document 1). The motor includes two rotors. The hydraulic mechanism supplies hydraulic oil to a phase change mechanism provided on the rotor of the motor. In this device, when the temperature of the hydraulic oil is below a predetermined temperature, the stator coil of the motor is energized to heat the hydraulic oil. This improves the responsiveness of the phase change at low temperatures. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-44805 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, a drive device has also been proposed that includes a power storage device, a motor having a three-phase coil, and first and second inverters that are connected to a power line to which the power storage device is connected and that are connected to one end and the other end of the three-phase coil and have a plurality of first and second switching elements.In such a drive device in which the first and second inverters and the motor are H-connected, it is recognized that an important issue is to increase the amount of heat generated by the motor and the first and second inverters in order to heat the power storage device.

[0005] The main object of the drive device of the present disclosure is to increase the amount of heat generated. [Means for solving the problem]

[0006] The driving device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The drive device of the present disclosure comprises: a power storage device; a motor having a three-phase coil; a first inverter connected to a power line to which the power storage device is connected and connected to one end of the three-phase coil, the first inverter having a plurality of first switching elements; a second inverter connected to the power line and to the other end of the three-phase coil, the second inverter having a plurality of second switching elements; a cooling device that cools the power storage device, the motor, and the first and second inverters using a cooling medium; a control device that controls the first and second inverters based on a torque command of the motor; A drive device comprising: The control device controls the first and second inverters so that all phase currents of the three phases of the three-phase coil of the motor circulate from one of the first and second inverters to the three phases via the power line and the other of the first and second inverters. The gist of this is as follows.

[0008] In the drive device disclosed herein, the first and second inverters are controlled so that all three phase currents of the three-phase coils of the motor circulate from one of the first and second inverters to the three phases via the power line and the other of the first and second inverters. This allows more current to flow through the motor and the first and second inverters. As a result, the amount of heat generated by the motor and the first and second inverters can be increased.

[0009] In the drive device of the present disclosure, the control device may feedback control the first and second inverters so that each phase current of the motor becomes a current based on the required heat amount required to raise the temperature of the power storage device. In this way, heat can be generated more appropriately using the motor and the first and second inverters.

[0010] In the drive device of the present disclosure, the control device may feedback control the first and second inverters so that a zero-phase current, which is the sum of the phase currents of the motor, becomes a current based on the heat quantity required to raise the temperature of the power storage device. In this way, heat can be generated more appropriately using the motor and the first and second inverters.

[0011] Furthermore, the drive device of the present disclosure may include a load device attached to at least one of the positive and negative power lines, which allows heat generation by the load device to be used in addition to the motor and the first and second inverters, thereby improving the amount of heat generation. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of an electric vehicle equipped with a drive device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing an example of a functional block in the control of the first and second inverters by the ECU at low temperatures. [Figure 3] FIG. 2 is an explanatory diagram illustrating an example of a current flow in the electric vehicle according to the embodiment. [Figure 4] FIG. 2 is an explanatory diagram for explaining the relationship between each phase current and a zero-phase current which is the sum of the phase currents. [Figure 5] FIG. 10 is a block diagram showing an example of a functional block in the control of the first and second inverters by the ECU in another embodiment at low temperatures. DETAILED DESCRIPTION OF THE INVENTION

[0013] A mode (embodiment) for carrying out the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of an electric vehicle 10 equipped with a drive device according to an embodiment of the present disclosure. As shown in the figure, the electric vehicle 10 of the embodiment includes a motor 20, first and second inverters 22, 24, a battery 26 as an electricity storage device, a switching device 32 as a load device, a cooling device 40, and an electronic control unit (hereinafter referred to as "ECU") 50 as a control device.

[0014] Motor 20 is configured as a three-phase AC motor having, for example, a rotor with a permanent magnet embedded in a rotor core and a stator with three-phase (U-phase, V-phase, W-phase) coils wound around a stator core. The rotor is connected to a drive shaft that is connected to drive wheels via a differential gear.

[0015] The first and second inverters 22, 24 are connected to a power line 28 (positive line 28p and negative line 28n) to which a battery 26 is connected, and are also connected to one end and the other end of the three-phase coils of the motor 20. The first inverter 22 includes six transistors (first switching elements) T11 to T16 as switching elements and six diodes D11 to D16 connected in parallel to the six transistors T11 to T16, respectively. The transistors T11 to T16 are arranged in pairs, two at a time, on the source side and two at the sink side of the positive line 28p and the negative line 28n. Each of the connection points of two transistors in a pair of the transistors T11 to T16 is connected to one end of the three-phase coils of the motor 20. The second inverter 24, like the first inverter 22, includes six transistors (second switching elements) T21 to T26 as switching elements and six diodes D21 to D26. The transistors T21 to T26 are arranged in pairs, two at a time, on the source side and two at the sink side of the positive line 28p and the negative line 28n. The connection points of two transistors that make up a pair of the transistors T21 to T26 are connected to the other end of the three-phase coil of the motor 20. The battery 26 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the power line 28 (the positive line 28p and the negative line 28n). A smoothing capacitor 30 is connected to the power line 28. In this embodiment, the battery 26, the capacitor 30, the first inverter 22, and the second inverter 24 are connected in this order on the power line 28.

[0016] The switching device 32 is attached to the positive line 28p of the power line 28. The switching device 32 includes two transistors T31 and T32 and two diodes D31 and D32. The transistors T31 and T32 are attached in series to the positive line 28p. The diode D31 is connected in parallel to the transistor T31 so that the forward direction is from the first inverter 22 to the second inverter 24. The diode D32 is connected in parallel to the transistor T32 so that the forward direction is from the second inverter 24 to the first inverter 24.

[0017] The cooling device 40 has a circulation flow path 42, a radiator 44, and an electric pump 46. The circulation flow path 42 is configured as a flow path for circulating a cooling medium such as coolant through the battery 26, the first inverter 22, the motor 20, the second inverter 24, and the radiator 44 in this order. The electric pump 46 circulates the cooling medium through the circulation flow path 42. Note that the circulation flow path 42 may also be configured as a flow path for circulating the cooling medium through the second inverter 24, the motor 20, the first inverter 22, the battery 26, and the radiator 44 in this order.

[0018] The ECU 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and logic ICs. The ECU 50 receives signals from various sensors. The input signals include, for example, rotational position θm from rotational position sensor 20a that detects the rotational position of the rotor of motor 20, phase currents Iu, Iv, Iw of each phase of motor 20 from current sensors 22u, 22v, 22w that detect the phase current of each phase of motor 20, voltage Vb of battery 26 from voltage sensor 26v, current Ib of battery 26 from current sensor 26i, temperature Tb of battery 26 from temperature sensor 26t, voltage VH of capacitor 30 (power line 28) from voltage sensor 30v, an on / off signal from power switch 60, the operating position (shift position SP) of shift lever 61 from shift position sensor 62, the depression amount of accelerator pedal 63 (accelerator opening Acc) from accelerator pedal position sensor 64, the depression amount of brake pedal 65 (brake pedal position BP) from brake pedal position sensor 66, and vehicle speed V from vehicle speed sensor 67. The ECU 50 outputs switching control signals to the transistors T11 to T16 and T21 to T26 of the first and second inverters 22 and 24, and to the transistors T31 and T32 of the switching device 32. The ECU 50 calculates the electrical angle θe and rotation speed Nm of the motor 20 based on the rotational position θm of the rotor of the motor 20, and calculates the power storage rate SOC of the battery 26 based on the integrated value of the current Ib of the battery 26.

[0019] In the electric vehicle 10 of this embodiment, the ECU 50 sets the required torque Td* required for driving based on the accelerator opening Acc and the vehicle speed V, sets the torque command Tm* for the motor 20 so that the vehicle drives with the set required torque Td*, and performs switching control of the transistors T11 to T16 and T21 to T26 of the first and second inverters 22 and 24 based on the set torque command Tm*.

[0020] Next, the operation of the electric vehicle 10, particularly the control of the first and second inverters 22, 24 at low temperatures, will be described. FIG. 2 is a block diagram showing an example of functional blocks in the control of the first and second inverters 22, 24 by the ECU 50 at low temperatures. The ECU 50 includes, as functional blocks shown in FIG. 2, a current command setting unit 500, a feedback (FB) correction term setting unit 510, and a PWM signal generating unit 520. Here, "at low temperatures" may include a time when the outside air temperature is below a predetermined temperature (e.g., 1°C, 3°C, 5°C, etc.) or a time when the temperature is too low for the battery 26 to function properly. It is assumed that the transistors T31 and T32 of the switching device 32 are on and the electric vehicle 10 is stopped.

[0021] The current command setting unit 500 sets current commands Iu*, Iv*, and Iw* for the motor 20 based on the required heat quantity Qreq required to heat the battery 26, and outputs the set current commands Iu*, Iv*, and Iw*. The ECU 50 determines in advance, through experiments, analysis, machine learning, or the like, the relationship between the difference between the current temperature Tb of the battery 26 measured by the temperature sensor 26t and the lower limit temperature of the temperature range in which the battery 26 can demonstrate its performance, and the required heat quantity Qreq, and stores this relationship in ROM. The required heat quantity Qreq is set from this relationship and the difference between the temperature Tb of the battery 26 measured by the temperature sensor 26t and the lower limit temperature of the temperature range in which the battery 26 can demonstrate its performance. The current command setting unit 500 sets the current commands Iu*, Iv*, and Iw* so that they are the same current amount in the same direction and are larger when the requested heat quantity Qreq is large than when it is small, within a range that does not exceed the maximum current Immax allowed for the motor 20 and the maximum current Iinvmax allowed for the first and second inverters 22, 24.

[0022] The FB correction term setting unit 510 receives the differences between the current commands Iu*, Iv*, Iw* and the phase currents Iu, Iv, Iw of the respective phases of the motor 20 from the current sensors 22u, 22v, 22w, sets feedback correction terms Dfbu, Dfbv, Dfbw of the duty command D* to cancel out the differences between the current commands Iu*, Iv*, Iw* and the phase currents Iu, Iv, Iw, and outputs the set feedback correction terms Dfbu, Dfbv, Dfbw. Here, the duty command D* is the ratio of the on time of each transistor in one cycle (the sum of the on time and off time of each transistor).

[0023] The PWM signal generating unit 520 receives duty commands Du1*, Dv1*, Dw1* of the first inverter 22, which are obtained by adding feedback correction terms Dfbu, Dfbv, Dfbw to a predetermined basic value Db of the duty index, and duty commands Du2*, Dv2*, Dw2* of the second inverter 24, which are obtained by adding the basic value Db (for example, 50%) to the feedback correction terms Dfbu, Dfbv, Dfbw multiplied by a value −1, and generates duty commands Du2*, Dv2*, Dw2* of the second inverter 24. The power supply control circuit 21 generates PWM signals for switching the transistors T11 to T16 and T21 to T26 of the first and second inverters 22 and 24 by comparing the power supply commands Du1*, Dv1*, Dw1*, Du2*, Dv2*, and Dw2* with a triangular wave (carrier wave), and outputs the generated PWM signals to the first and second inverters 22 and 24 to control the switching of the transistors T11 to T16 and T21 to T26 of the first and second inverters 22 and 24. Through this control, the first and second inverters 22 and 24 are feedback-controlled so that the phase currents Iu, Iv, and Iw of the motor 20 become currents based on the requested heat quantity Qreq.

[0024] FIG. 3 is an explanatory diagram illustrating an example of current flow in the electric vehicle 10 of this embodiment. FIG. 4 is an explanatory diagram illustrating the relationship between the phase currents Iu, Iv, and Iw and the zero-phase current I0 (= Iu + Iv + Iw), which is the sum of the phase currents Iu, Iv, and Iw. In FIGS. 3 and 4, thick arrows indicate the direction of current. In the electric vehicle 10 of this embodiment, the first and second inverters 22 and 24 are controlled so that the phase currents Iu, Iv, and Iw of each phase of the motor 20 flow in a direction from the first inverter 22 to the second inverter 24 and have the same current value. Through this control, as shown in FIG. 3, the current flows from each phase of the motor 20 through the second inverter 24, splitting into a positive line 28p and a negative line 28n of the power line 28, and then circulates to each phase via the first inverter 22. 4, when the phase currents Iu, Iv, and Iw are each 200 A, the zero-phase current I0 is 600 A. The phase currents Iu, Iv, and Iw can be increased according to the requested heat quantity Qreq as long as they do not exceed the maximum current Immax allowed for the motor 20 and the maximum current Iinvmax allowed for the first and second inverters 22, 24. This allows for a larger amount of heat to be generated by the motor 20, the first and second inverters 22, 24, and the switching device 32. This promotes the temperature rise of the cooling medium in the cooling device 40, thereby promoting the heating of the battery 26. This makes it possible to more appropriately suppress deterioration of the battery 26 due to low temperatures.

[0025] In the electric vehicle 10 equipped with the drive device of the embodiment described above, the first and second inverters 22, 24 are controlled so that all three phase currents Iu, Iv, Iw of the three-phase coil of the motor 20 circulate to the three phases from the first inverter 22 via the power line 28 and the second inverter 24, thereby making it possible to further increase the amount of heat generated by the motor 20 and the first and second inverters 22, 24.

[0026] In addition, by feedback controlling the first and second inverters 22, 24 so that the phase currents Iu, Iv, Iw of the motor 20 become currents based on the required heat quantity Qreq required to heat up the battery 26, heat can be generated more appropriately using the motor 20 and the first and second inverters 22, 24.

[0027] In the above-described embodiment, the first and second inverters 22, 24 are feedback-controlled so that the phase currents Iu, Iv, and Iw of the motor 20 are set to currents based on the required heat quantity Qreq. However, as in another embodiment described below, the first and second inverters 22, 24 may be feedback-controlled so that the zero-phase current I0 is set to a current based on the required heat quantity Qreq. FIG. 5 is a block diagram showing an example of functional blocks used by the ECU 50 to control the first and second inverters 22, 24 at low temperatures in another embodiment. The ECU 50 includes, as functional blocks shown in FIG. 5, a current command setting unit 600, a current calculation unit 605, a feedback (FB) correction term setting unit 610, and a PWM signal generation unit 620. This routine is executed when the vehicle is stopped at low temperatures where the outside air temperature is equal to or lower than a predetermined temperature (e.g., 1°C, 3°C, 5°C, etc.). Here, the transistors T31 and T32 of the switching device 32 are turned on.

[0028] The current command setting unit 600 sets a current command I0* for the zero-phase current I0 based on the requested heat quantity Qreq and outputs the set current command I0*. The current command setting unit 600 sets the current command I0* to be larger when the requested heat quantity Qreq is large than when it is small.

[0029] The current calculation unit 605 inputs the phase currents Iu, Iv, and Iw of each phase of the motor 20 from the current sensors 22u, 22v, and 22w, calculates the zero-phase current I0 (= Iu + Iv + Iw) as the sum of the phase currents Iu, Iv, and Iw, and outputs the calculated zero-phase current I0.

[0030] The FB correction term setting unit 610 inputs the difference between the current command I0* and the zero-phase current I0, sets a feedback correction term Dfb of the duty command to cancel out the difference between the current command I0* and the zero-phase current I0, and outputs the set feedback correction term Dfb.

[0031] The PWM signal generating unit 620 generates a PWM signal for switching the transistors T11-T16 of the first inverter 22 by comparing a duty command D1* of the first inverter 22, which is obtained by adding a feedback correction term Dfb to the above-mentioned basic value Db, with a triangular wave (carrier wave), and outputs the generated PWM signal to the first inverter 22 to control the switching of the transistors T11-T16 of the first inverter 22. The PWM signal generating unit 620 also generates a PWM signal for switching the transistors T21-T26 of the second inverter 24 by comparing a duty command D2* of the second inverter 22, which is obtained by subtracting the feedback correction term Dfb from the above-mentioned basic value Db, with a triangular wave (carrier wave), and outputs the generated PWM signal to the second inverter 24 to control the switching of the transistors T21-T26 of the second inverter 24. Through this control, the first and second inverters 22, 24 are feedback-controlled so that the zero-phase current I0 becomes a current based on the requested heat quantity Qreq. This allows the current of the motor 20 to be the same as the current exemplified in Fig. 3, and the amount of heat generated can be increased, thereby more appropriately suppressing deterioration of the battery 26 due to low temperatures.

[0032] In the above-described embodiment, the first and second inverters 22, 24 are feedback-controlled so that the phase currents Iu, Iv, Iw of the motor 20 become currents based on the requested heat quantity Qreq required to raise the temperature of the battery 26. However, it is also possible to set the duty commands Du1*, Dv1*, Dw1*, Du2*, Dv2*, Dw2* of the first and second inverters 22, 24 based on the requested heat quantity Qreq, compare the set duty commands Du1*, Dv1*, Dw1*, Du2*, Dv2*, Dw2* with a triangular wave (carrier wave) to generate PWM signals for switching the transistors T11 to T16, T21 to T26 of the first and second inverters 22, 24, and use the generated PWM signals to perform feedforward control on the first and second inverters 22, 24.

[0033] In the above-described embodiment, the first and second inverters 22, 24 are controlled so that all of the phase currents Iu, Iv, and Iw of the three phases of the three-phase coils of the motor 20 circulate from the first inverter 22 to the three phases via the power line 28 and the second inverter 24. However, the first and second inverters 22, 24 may be controlled so that the phase currents Iu, Iv, and Iw circulate from the second inverter 24 to the three phases via the power line 28 and the first inverter 22.

[0034] In the above-described embodiment, the switching device 32 is provided on the positive line 28p of the power line 28. However, the switching device 32 may also be provided on the negative line 28n of the power line 28, or the switching device 32 may be provided on each of the positive line 28p and the negative line 28n of the power line 28, or such a switching device 32 may not be provided.

[0035] In the above-described embodiment, the drive unit is mounted on an electric vehicle 10 equipped with a motor 20, but is not limited to this. For example, the drive unit may be mounted on a hybrid vehicle equipped with an engine in addition to a motor, or on a fuel cell vehicle equipped with a fuel cell in addition to a motor. The drive unit may also be mounted on a moving object other than a vehicle or on stationary construction equipment.

[0036] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the battery 26 corresponds to the "electricity storage device," the motor 20 corresponds to the "motor," the first and second inverters 22 and 24 correspond to the "first and second inverters," the cooling device 40 corresponds to the "cooling device," and the ECU 50 corresponds to the "control device."

[0037] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0038] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0039] The present disclosure is applicable to industries such as the drive device manufacturing industry. [Explanation of symbols]

[0040] 10 electric vehicle, 20 motor, 20a rotational position sensor, 22 first inverter, 22u, 22v, 22w current sensor, 24 second inverter, 26 battery, 26i current sensor, 26t temperature sensor, 26v voltage sensor, 28 power line, 28n negative line, 28p positive line, 30 capacitor, 30v voltage sensor, 32 switching device, 40 cooling device, 42 circulation flow path, 44 radiator, 46 electric pump, 50 electronic control unit (ECU), 60 power switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 brake pedal position sensor, 67 vehicle speed sensor, 500 current command setting unit, 510 feedback (FB) correction term setting unit, 520 PWM signal generation unit, 600 Current command setting unit, 605 current calculation unit, 610 feedback (FB) correction term setting unit, 620 PWM signal generation unit, D11 to D16, D21 to D26, D31, D32 diodes, T11 to T16, T21 to T26, T31, T32 transistors.

Claims

1. a power storage device; a motor having a three-phase coil; a first inverter connected to a power line to which the power storage device is connected and connected to one end of the three-phase coil, the first inverter having a plurality of first switching elements; a second inverter connected to the power line and to the other end of the three-phase coil, the second inverter having a plurality of second switching elements; a cooling device that cools the power storage device, the motor, and the first and second inverters using a cooling medium; a control device that controls the first and second inverters based on a torque command of the motor; A drive device comprising: The control device controls the first and second inverters so that all phase currents of the three phases of the three-phase coil of the motor circulate from one of the first and second inverters to the three phases via the power line and the other of the first and second inverters. Drive unit.

2. 2. The drive device according to claim 1, The control device feedback controls the first and second inverters so that each phase current of the motor becomes a current based on a required amount of heat required to increase the temperature of the power storage device. Drive unit.

3. 2. The drive device according to claim 1, The control device feedback controls the first and second inverters so that a zero-phase current, which is a sum of the phase currents of the motor, becomes a current based on a required amount of heat required to increase the temperature of the power storage device. Drive unit.

4. 3. The drive device according to claim 1 or 2, a load device attached to at least one of the positive and negative lines of the power line; A drive unit comprising:

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