Drive unit

Abstract

To achieve both of reduction of noise due to a current ripple and reduction of a switching loss of an inverter in the time of engine start-up.SOLUTION: A drive device includes: an engine; a motor connected to the engine; an inverter which drives the motor by switching multiple switching elements; a power storage device connected to the inverter via a power line; and a control device which controls the engine and the inverter. The control device controls the inverter by pulse width modulation control using a three-phase modulation mode and a first carrier frequency when not in the time of engine start-up that starts the engine with cranking of the engine by the motor, and controls the inverter by the pulse width modulation control using a two-phase modulation mode and a second carrier frequency higher than the first carrier frequency in the time of engine start-up.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A conventional drive system of this type includes an engine, a motor connected to the engine, an inverter that drives the motor by switching six switching transistors, a DC power supply connected to the inverter via a power line, and a control device that controls the engine and the inverter (see, for example, Patent Document 1). In this drive system, when the target torque and rotation speed of the motor are outside of a predetermined range, the carrier frequency is set to a low frequency, and the inverter is controlled by PWM control using a carrier frequency determined as a three-phase modulation mode or a two-phase modulation mode. When the target torque and rotation speed of the motor are within a predetermined range, the carrier frequency is set to a high frequency higher than the low frequency, and the inverter is controlled by PWM control using a carrier frequency determined as a two-phase modulation mode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-118544 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described drive device, when starting the engine by cranking the engine using the motor, the target torque and rotation speed of the motor may fall outside the predetermined range, causing the carrier frequency to be set to a low frequency and the three-phase modulation mode to be selected. In this case, there is a possibility that noise due to current ripple may increase during engine start. When starting the engine, the motor needs to output a relatively large torque to crank the engine, which can easily cause noise and other issues to become apparent.

[0005] The main object of the drive device of the present disclosure is to achieve both a reduction in noise caused by current ripple and a reduction in inverter switching loss when starting the engine. [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 drive device including an engine, a motor connected to the engine, an inverter that drives the motor by switching a plurality of switching elements, a power storage device connected to the inverter via a power line, and a control device that controls the engine and the inverter, the control device controls the inverter by pulse width modulation control using a three-phase modulation mode and a first carrier frequency when not starting the engine by cranking the engine using the motor, and when starting the engine, controls the inverter by pulse width modulation control using a two-phase modulation mode and a second carrier frequency higher than the first carrier frequency. The gist of this is as follows.

[0008] In the drive device of the present disclosure, when the engine is not being started by cranking the engine using the motor, the inverter is controlled by pulse width modulation control (PWM control) using a three-phase modulation mode and a first carrier frequency, and when the engine is being started, the inverter is controlled by pulse width modulation control using a two-phase modulation mode and a second carrier frequency higher than the first carrier frequency. This makes it possible to reduce both noise caused by current ripple and switching loss of the inverter when the engine is being started.

[0009] In the drive device of the present disclosure, the control device may set the second carrier frequency at engine start so that the higher the temperature of the inverter and / or the higher the temperature of the cooling water, the lower the second carrier frequency. In this way, the second carrier frequency can be set more appropriately.

[0010] In the drive device of the present disclosure, when the engine is not starting and the operating point of the motor is within a predetermined range, the control device may control the inverter by the pulse width modulation control using the two-phase modulation mode and a third carrier frequency that is higher than the first carrier frequency and lower than the second carrier frequency. In this way, when the operating point of the motor is within the predetermined range, it is possible to achieve both a reduction in noise due to current ripple and a reduction in switching loss of the inverter. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a hybrid vehicle 20 equipped with a drive device according to the present embodiment. [Figure 2] 10 is an explanatory diagram showing an example of how voltage commands Vu*, Vv*, Vw* for each phase and a PWM signal for a transistor T11 (upper arm of the U phase) are generated when a three-phase modulation mode is used. FIG. [Figure 3] 10 is an explanatory diagram showing an example of how voltage commands Vu*, Vv*, Vw* for each phase and a PWM signal for a transistor T11 are generated when a two-phase modulation mode is used. FIG. [Figure 4] 10 is a flowchart showing an example of a setting process executed by a motor ECU 38. [Figure 5] FIG. 4 is an explanatory diagram showing an example of a frequency setting map. [Figure 6] 10 is a flowchart illustrating an example of a setting process according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a hybrid vehicle 20 equipped with a drive system according to the present embodiment. As shown in the figure, the hybrid vehicle 20 includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a motor 30, an inverter 32, a cooling device 33, a motor electronic control unit (hereinafter referred to as "motor ECU") 38, a clutch K0, a clutch WSC, a transmission 40, a battery 50 serving as a power storage device, a battery electronic control unit (hereinafter referred to as "battery ECU") 52, a system main relay 56, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70. In this embodiment, the engine 22, the motor 30, the inverter 32, the cooling device 33, the battery 50, the engine ECU 24, the motor ECU 38, and the HVECU 70 primarily correspond to the drive system.

[0013] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline, diesel, etc. A crankshaft 23 of the engine 22 is connected to a rotary shaft 31 of a motor 30 via a clutch K0.

[0014] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The engine ECU 24 receives signals from various sensors via the input ports. Examples of signals received by the engine ECU 24 include a crank angle θcr of the engine 22 from a crank position sensor 23a that detects the rotational position of a crankshaft 23 of the engine 22. The engine ECU 24 outputs various control signals via the output ports. Examples of signals received by the engine ECU 24 include a control signal for a throttle valve, a control signal for a fuel injection valve, and a control signal for a spark plug. The engine ECU 24 is connected to the HVECU 70 via the communication ports. The engine ECU 24 calculates the engine speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 23a.

[0015] The motor 30 is configured as a synchronous generator motor and has a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. A rotating shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0 and to the input shaft 41 of the transmission 40 via a clutch WSC.

[0016] The inverter 32 is used to drive the motor 30 and is connected to the battery 50 via a power line 54. The inverter 32 has six transistors T11-T16 as switching elements and six diodes D11-D16 connected in parallel to the six transistors T11-T16, respectively. The transistors T11-T16 are arranged in pairs, two at a time, so that one is on the source side and the other is on the sink side with respect to the positive and negative lines of the power line 54. The junctions of the two transistors in each pair are connected to the coils of the corresponding phases (U phase, V phase, W phase) of the motor 30. Therefore, when a voltage is applied to the inverter 32, the motor ECU 38 adjusts the proportion of the on-time of the paired transistors T11-T16, thereby generating a rotating magnetic field in the three-phase coils and driving the motor 30 to rotate.

[0017] The cooling device 33 is configured as a cooling device that cools the inverter 32. The cooling device 33 includes a circulation flow path 34 that includes a cooling flow path for the inverter 32, a radiator 35 incorporated in the circulation flow path 34, and a water pump 36 that circulates the cooling water in the circulation flow path 34.

[0018] The motor ECU 38 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The motor ECU 38 receives signals from various sensors via its input ports. Examples of signals received by the motor ECU 38 include the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, the phase currents Iu and Iv of the motor 30 from current sensors 30u and 30v that detect the currents of the motor 30, the temperature Ti of the inverter 32 from a temperature sensor 30t attached to the inverter 32, and the coolant temperature Tw of the cooling device 33 from a temperature sensor 37 attached to a circulation path 34 of the cooling device 33. The motor ECU 38 outputs various control signals via its output ports. Examples of signals output by the motor ECU 38 include switching control signals for the transistors T11 to T16 of the inverter 32 and a control signal for the water pump 36. The motor ECU 38 is connected to the HVECU 70 via a communication port. The motor ECU 38 calculates the electrical angle θe and the rotation speed Nm of the motor 30 based on the rotation position θm of the rotor (rotary shaft 31) of the motor 30 from the rotation position sensor 30a.

[0019] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30. The clutch WSC is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects the rotating shaft 31 of the motor 30 and the input shaft 41 of the transmission 40.

[0020] Transmission 40 is configured as, for example, a six-speed automatic transmission, and has an input shaft 41, an output shaft 42, a plurality of planetary gears, and a plurality of hydraulically driven friction engagement elements (clutches and brakes). Input shaft 41 is connected to the rotor of motor 30 via clutch WSC, and output shaft 42 is connected to drive wheels 49 via differential gear 48. Transmission 40 establishes first to sixth forward speeds and reverse speeds by engaging or disengaging the plurality of friction engagement elements, thereby connecting input shaft 41 and output shaft 42 (transmitting power between them) or disconnecting input shaft 41 and output shaft 42.

[0021] The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery. As described above, the battery 50 is connected to the inverter 32 via the power line 54.

[0022] The battery ECU 52 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The battery ECU 52 receives signals from various sensors via the input port. Examples of signals received by the battery ECU 52 include the voltage Vb of the battery 50 from a voltage sensor attached between the terminals of the battery 50, the current Ib (positive when discharging) of the battery 50 from a current sensor attached to the output terminals of the battery 50, and the temperature Tb of the battery 50 from a temperature sensor attached to the battery 50. The battery ECU 52 is connected to the HVECU 70 via the communication port. The battery ECU 52 calculates the power storage percentage SOC of the battery 50 based on the integrated value of the current Ib of the battery 50 from the current sensor. The power storage percentage SOC is the ratio of the amount of power that can be discharged from the battery 50 to the total capacity of the battery 50.

[0023] The system main relay 56 is provided on the power line 54 and connects and disconnects the inverter 32 side and the battery 50 side.

[0024] The HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The HVECU 70 receives signals from various sensors via input ports. Examples of signals received by the HVECU 70 include a rotation speed Ni of the input shaft 41 of the transmission 40 from a rotation speed sensor 41a that detects the rotation speed of the input shaft 41, and a rotation speed No of the output shaft 42 from a rotation speed sensor 42a that detects the rotation speed of the output shaft 42 of the transmission 40. Other examples include a start signal from a start switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of the shift lever 81. Other examples include an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the depression amount of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87. The HVECU 70 outputs various control signals via output ports. Examples of signals output by the HVECU 70 include a control signal to the clutch K0, a control signal to the clutch WSC, a control signal to the transmission 40, and a control signal to the system main relay 56. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 38, and the battery ECU 52 via communication ports.

[0025] In the hybrid vehicle 20 of this embodiment, the engine 22, motor 30 (inverter 32), clutch K0, clutch WSC, and transmission 40 are controlled by cooperative control between the HVECU 70, engine ECU 24, and motor ECU 38 so as to travel in a hybrid driving (HV driving) mode or an electric driving (EV driving) mode. Here, the HV driving mode is a driving mode in which the clutch K0 and the clutch WSC are both engaged and the vehicle travels with rotation of the engine 22. The EV driving mode is a driving mode in which the clutch K0 is released and the clutch WSC is engaged and the vehicle travels without rotation of the engine 22. Note that the engagement states of the clutch K0 and the clutch WSC each include not only a fully engaged state but also a slip-engaged state.

[0026] In the HV traveling mode, the HVECU 70 sets a target gear St* of the transmission 40 based on the accelerator opening Acc and the vehicle speed V, and controls the transmission 40 so that the gear St of the transmission 40 becomes the target gear St*. The HVECU 70 also sets a required torque To* required for traveling (required from the output shaft 42 of the transmission 40) based on the accelerator opening Acc and the vehicle speed V, and sets a required torque Ti* of the input shaft 41 of the transmission 40 based on the set required torque To* and the gear St (gear ratio Gt) of the transmission 40. Next, the HVECU 70 sets a target torque Te* of the engine 22 and a torque command Tm* of the motor 30 so that the required torque Ti* is output to the input shaft 41 and the battery 50 is charged and discharged at the required charge / discharge power Pb*. The HVECU 70 then transmits the target torque Te* of the engine 22 to the engine ECU 24, and transmits the torque command Tm* of the motor 30 to the motor ECU 38. The engine ECU 24 performs operation control (intake air amount control, fuel injection control, ignition control, etc.) of the engine 22 so that the engine 22 operates based on the target torque Te*. The motor ECU 38 performs switching control of the transistors T11 to T16 of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0027] In the HV driving mode, when a stop condition for the engine 22 is met, such as when the required torque Ti* falls below the stop threshold Tiref1, the operation of the engine 22 is stopped and the clutch K0 is released, and the vehicle transitions to the EV driving mode.

[0028] In the EV driving mode, the HVECU 70 controls the transmission 40 in the same manner as in the HV driving mode. Also, the HVECU 70 sets the required torque Ti* of the input shaft 41 of the transmission 40 in the same manner as in the HV driving mode, sets the torque command Tm* of the motor 30 so that the set required torque Ti* is output to the input shaft 41, and transmits the set torque command Tm* to the motor ECU 38. The control of the inverter 32 by the motor ECU 38 has been described above.

[0029] In the EV driving mode, when a start condition for the engine 22 is met, such as when the required torque Ti* reaches or exceeds a start threshold Tiref2 that is greater than the stop threshold Tiref1, the engine 22 is started and the vehicle transitions to the HV driving mode. When starting the engine 22, the clutch K0 is brought into a fully engaged state via a slip engagement state, and cranking torque for the engine 22 is output from the motor 30 to crank the engine 22, and fuel injection control and ignition control for the engine 22 are initiated. The cranking torque is set, for example, to increase from a value of 0 to a relatively large torque, maintain that torque, and then gradually decrease. When starting the engine 22, the motor 30 outputs a torque that is the sum of the cranking torque of the engine 22 and the torque for driving.

[0030] Here, details of the control of the inverter 32 by the motor ECU 38 will be described. In this embodiment, the inverter 32 is controlled by pulse width modulation control (PWM control). First, d-axis and q-axis current commands Id* and Iq* are set based on the torque command Tm* of the motor 30. Next, assuming that the sum of the currents flowing through each phase (U-phase, V-phase, W-phase) of the motor 30 is zero, the phase currents Iu and Iv of the U-phase and V-phase are coordinate-transformed (three-phase to two-phase transformation) into d-axis and q-axis currents Id and Iq using the electrical angle θe of the motor 30. Then, d-axis and q-axis voltage commands Vd* and Vq* are set by current feedback control so that the differences between the d-axis and q-axis current commands Id* and Iq* and the d-axis and q-axis currents id and Iq are canceled out. Then, the d-axis and q-axis voltage commands Vd* and Vq* are converted to voltage commands Vu*, Vv*, and Vw* for each phase through coordinate conversion (2-phase-to-3-phase conversion) using three-phase modulation mode or two-phase modulation mode. Additionally, PWM signals for transistors T11-T16 are generated using the voltage commands Vu*, Vv*, and Vw* for each phase and a carrier wave (triangular wave), and the generated PWM signals are used to control the switching of transistors T11-T16. Figure 2 is an explanatory diagram showing an example of how the voltage commands Vu*, Vv*, and Vw* for each phase and the PWM signal for transistor T11 (the upper arm of the U phase) are generated when using three-phase modulation mode. Figure 3 is an explanatory diagram showing an example of how the voltage commands Vu*, Vv*, and Vw* for each phase and the PWM signal for transistor T11 are generated when using two-phase modulation mode. 2(a) and 3(a) show the voltage commands Vu*, Vv*, and Vw* for each phase, and FIGS. 2(b) and 3(b) show how the PWM signal of the transistor T11 is generated.

[0031] In this embodiment, when the temperature Ti of the inverter 32 becomes higher than the threshold value Tiot or the cooling water temperature Tw of the cooling device 33 becomes higher than the threshold value Twot, a protection process for the inverter 32, such as limiting the drive of the motor 30, is performed to prevent the inverter 32 from overheating.

[0032] Next, the operation of the hybrid vehicle 20 of this embodiment, in particular the process of setting the modulation mode Md and the carrier frequency fc, which is the frequency of the carrier wave, used to control the inverter 32, will be described. Fig. 4 is a flowchart showing an example of the setting process executed by the motor ECU 38. This setting process is executed repeatedly.

[0033] 4 is executed, the motor ECU 38 first inputs the start flag Fs (step S100). Here, the start flag Fs is input via communication with a value set by a start flag setting routine executed by the HVECU 70. In the start flag setting routine, the HVECU 70 sets the start flag Fs to a value of 1 when the engine 22 is started, specifically from the time when the start conditions for the engine 22 are met until the start of the engine 22 is completed, and sets the start flag Fs to a value of 0 when the engine 22 is not started.

[0034] Next, the value of the start-up flag Fs is checked (step S110). If the start-up flag Fs is set to 0, i.e., if the engine 22 is not starting, the modulation mode Md is set to three-phase modulation mode (step S120), and the carrier frequency fc is set to a relatively low frequency fc1 (step S130), and this setting process ends. This achieves both good controllability of the inverter 32 and reduced switching loss of the transistors T11 to T16 of the inverter 32.

[0035] When the start flag Fs is set to 1 in step S110, that is, when the engine 22 is started, the modulation mode Md is set to the two-phase modulation mode (step S140), and the start temperature Tist and start water temperature Twst, which are the temperature Ti of the inverter 32 and the coolant temperature Tw of the cooling device 33 at the start of starting the engine 22 (when the start flag F switches from 0 to 1), are input (step S150). Here, the start temperature Tist is the temperature Ti of the inverter 32 detected by the temperature sensor 30t at the start of starting the engine 22. The start water temperature Twst is the coolant temperature Tw of the cooling device 33 detected by the temperature sensor 37 at the start of starting the engine 22.

[0036] Next, a frequency fc2 based on the start temperature Tist and the start water temperature Twst is set as the carrier frequency fc (steps S160 and S170), and the setting process ends. Here, frequency c2 is set within a range somewhat higher than frequency fc1. Increasing carrier frequency fc reduces the current ripple of the current flowing through the power line 54 between the battery 50 and the inverter 32, thereby reducing noise due to current ripple that may occur in the battery 50, the system main relay 56, and the like. However, increasing carrier frequency fc increases the switching loss of the transistors T11 to T16 of the inverter 32, increasing the amount of heat generated therefrom, which tends to increase the temperature Ti of the inverter 32 and the temperature Tw of the cooling device 33. Based on this, by switching to two-phase modulation mode, the switching loss of the transistors T11 to T16 can be reduced compared to three-phase modulation mode. As a result, it is possible to achieve both reduced noise due to current ripple and reduced switching loss of the transistors T11 to T16 when starting the engine 22. When starting the engine 22, the motor 30 outputs a torque that is the sum of the cranking torque of the engine 22 and the torque for driving. Since the motor 30 tends to output a relatively large torque, noise caused by the influence of current ripples is likely to become apparent. Therefore, it is effective to change the modulation mode Md to a two-phase modulation mode and increase the carrier frequency fc. Note that if the frequency fc2 is set higher than the audible range, noise caused by current ripples can be further suppressed from being perceived by the driver.

[0037] In this embodiment, the frequency fc2 is set within a range that can prevent the inverter 32 temperature Ti from rising above the threshold value Tiot or the cooling water temperature Tw from rising above the threshold value Twot when the engine 22 is started, thereby preventing the inverter 32 from being protected. The frequency fc2 can be set, for example, by applying the start temperature Tist and the start water temperature Twst to a frequency setting map. The frequency setting map is determined in advance by experimentation, analysis, machine learning, or the like as a relationship between the start temperature Tist, the start water temperature Twst, and the frequency fc2, and is stored in the ROM or flash memory of the motor ECU 38. FIG. 5 is an explanatory diagram illustrating an example of the frequency setting map. 5, frequency fc2 is set to a sufficiently high value fc21 in the region where start temperature Tist is equal to or lower than threshold value Tist1, which is somewhat lower than threshold value Tiot, and where start water temperature Twst is equal to or lower than threshold value Twst1, which is somewhat lower than threshold value Twot. In the region where start temperature Tist is higher than threshold value Tist1, frequency fc2 is set to be lower relative to value fc21 as the start temperature Tist increases. In the region where start water temperature Twst is higher than threshold value Twst1, frequency fc2 is set to be lower relative to value fc21 as the start water temperature Twst increases. Since a higher carrier frequency fc increases the switching loss of transistors T11-T16 of inverter 32, which tends to increase the temperature Ti of inverter 32 and the temperature Tw of cooling device 33, setting carrier frequency fc to a frequency fc2 with the trend shown in FIG. 5 can prevent inverter temperature Ti from rising above threshold value Tiot or cooling water temperature Tw of cooling device 33 from rising above threshold value Twot during engine start-up, thereby preventing the inverter 32 from being protected from a malfunction. In other words, the region where the starting temperature Tist is below the threshold value Tist1 and the starting water temperature Twst is below the threshold value Twst1 can be said to be a region where, when the inverter 32 is controlled by PWM control using the carrier frequency fc of value fc21 and the two-phase modulation mode at the start of the engine 22, it is possible to prevent the temperature Ti of the inverter 32 from becoming higher than the threshold value Tiot and the cooling water temperature Tw of the cooling device 33 from becoming higher than the threshold value Twot.

[0038] In the drive device mounted on the hybrid vehicle 20 of this embodiment described above, when the engine 22 is not starting, the modulation mode Md is set to three-phase modulation mode, and the carrier frequency fc is set to frequency fc1, and the switching of the transistors T11 to T126 of the inverter 32 is controlled by PWM control using the set modulation mode Md and carrier frequency fc. When the engine 22 is starting, the modulation mode Md is set to two-phase modulation mode, and the carrier frequency fc is set to frequency fc2, which is higher than frequency fc1, and the switching of the transistors T11 to T126 of the inverter 32 is controlled by PWM control using the set modulation mode Md and carrier frequency fc. This makes it possible to reduce both noise due to current ripple and switching loss of the transistors T11 to T16 of the inverter 32 when the engine 22 is starting.

[0039] Furthermore, in the drive device mounted on the hybrid vehicle 20 of this embodiment, the frequency fc2 based on the start temperature Tist and the start water temperature Twst is set as the carrier frequency fc when starting the engine 22. This makes it possible to further prevent the temperature Ti of the inverter 32 from becoming higher than the threshold value Tiot or the cooling water temperature Tw of the cooling device 33 from becoming higher than the threshold value Twot when starting the engine 22, thereby preventing the protection process for the inverter 32 from being activated.

[0040] In the above-described embodiment, the frequency fc2 used when starting the engine 22 is set based on the start temperature Tist and the start water temperature Twst. However, the frequency fc2 may be set based on only one of the start temperature Tist and the start water temperature Twst, or a constant value may be used, as long as it is higher than the frequency fc1. Furthermore, instead of the start temperature Tist, which is the temperature Ti of the inverter 32 at the start of starting the engine 22, a representative temperature of the transistors T11-T16 and the diodes D11-D16 at the start of starting the engine 22, or the temperature of a substrate on which the transistors T11-T16 and the diodes D11-D16 are mounted, may be used. The representative temperature may be, for example, the temperature of one (a specific element) of the transistors T11-T16 and the diodes D11-D16, or the maximum value of the temperatures of the transistors T11-T16 and the diodes D11-D16.

[0041] In the above-described embodiment, the motor ECU 38 executes the setting process of Fig. 4. However, instead of this, the motor ECU 38 may execute the setting process of Fig. 6. The setting process of Fig. 6 is the same as the setting process of Fig. 4 except for the addition of the processes of steps S200 to S230. Therefore, the same step numbers are assigned to the same processes in the setting process of Fig. 6 as those in the setting process of Fig. 4, and detailed descriptions thereof will be omitted.

[0042] 6, when the start flag Fs is set to 0 in step S110, i.e., when the engine 22 is not starting, the motor ECU 38 inputs the rotation speed Nm and torque command Tm* of the motor 30 (step S200). Here, the rotation speed Nm of the motor 30 is input with a value calculated based on the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a. The torque command Tm* of the motor 30 is input with a value set based on the required torque Ti* of the input shaft 41, etc.

[0043] Next, it is determined whether the operating point of motor 30 (rotation speed Nm and torque command Tm*) is within a predetermined region (step S210). Here, the predetermined region is determined in advance by experiment, analysis, machine learning, etc. as a region where noise due to current ripple is likely to be perceived by the driver (a region where noise should be reduced). If it is determined in step S210 that the operating point of motor 30 is outside the predetermined region, the processes of steps S120 and S130 described above are executed. Specifically, the modulation mode Md is set to three-phase modulation mode and the carrier frequency fc is set to frequency fc1, and this setting process ends.

[0044] If it is determined in step S210 that the operating point of motor 30 is outside the predetermined range, the modulation mode Md is set to two-phase modulation mode (step S220), and the carrier frequency fc is set to frequency fc3, which is higher than frequency fc1 and lower than frequency fc2 (step S230), and this setting process ends. When the operating point of motor 30 is within the predetermined range, the carrier frequency fc is set to be higher than when the operating point of motor 30 is outside the predetermined range, thereby preventing the driver from perceiving noise due to current ripple. Furthermore, by switching to two-phase modulation mode at this time, the switching loss of transistors T11 to T16 can be reduced compared to three-phase modulation mode.

[0045] In the above-described embodiment, the hybrid vehicle 20 is provided with the battery 50 as the power storage device. However, it is sufficient if the hybrid vehicle 20 is provided with a device capable of storing power, and the hybrid vehicle 20 may be provided with a capacitor or the like.

[0046] In the above-described embodiment, the hybrid vehicle 20 includes the engine ECU 24, the motor ECU 38, the battery ECU 52, and the HVECU 70. However, at least two of these may be configured as an integrated unit.

[0047] In the above-described embodiment, the hybrid vehicle 20 is configured such that the engine 22 is connected to the drive wheels 49 via the transmission 40, clutch WSC, motor 30, and clutch K0, and the battery 50 is connected to the inverter 32 that drives the motor 30 via a power line 54. However, the present invention is not limited to this. For example, a single-pinion planetary gear may have a sun gear connected to a first motor, a carrier connected to the engine, and a ring gear connected to a drive shaft that is connected to the drive wheels, a second motor connected to the drive shaft, and a battery connected to first and second inverters that drive the first and second motors, respectively, via power lines.

[0048] In the above-described embodiment, the drive unit is mounted on the hybrid vehicle 20. However, the drive unit may be mounted on a moving body other than a vehicle, or may be mounted on construction equipment or the like.

[0049] 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 explained. In the embodiment, the engine 22 corresponds to the "engine", the motor 30 corresponds to the "motor", the inverter 32 corresponds to the "inverter", the battery 50 corresponds to the "electricity storage device", the engine ECU 24, the motor ECU 38, and the HVECU 70 correspond to the "control device", and the cooling device 33 corresponds to the "cooling device".

[0050] 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.

[0051] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments and can, of course, be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0052] The present disclosure is applicable to industries such as the drive device manufacturing industry. [Explanation of symbols]

[0053] 20 hybrid vehicle, 22 engine, 23 crankshaft, 24 engine ECU, 30 motor, 30a rotational position sensor, 30t temperature sensor, 30u current sensor, 31 rotating shaft, 32 inverter, 33 cooling device, 34 circulation flow path, 35 radiator, 36 water pump, 37 temperature sensor, 38 motor ECU, 40 transmission, 41 input shaft, 42 output shaft, 50 battery, 52 battery ECU, 54 power line, 56 system main relay, 70 HVECU, D11 to D16 diodes, T11 to T16 transistors.

Claims

1. A drive device including an engine, a motor connected to the engine, an inverter that drives the motor by switching a plurality of switching elements, a power storage device connected to the inverter via a power line, and a control device that controls the engine and the inverter, the control device controls the inverter by pulse width modulation control using a three-phase modulation mode and a first carrier frequency when not starting the engine by cranking the engine using the motor, and when starting the engine, controls the inverter by pulse width modulation control using a two-phase modulation mode and a second carrier frequency higher than the first carrier frequency. Drive unit.

2. 2. The drive device according to claim 1, a cooling device that cools the inverter using cooling water; the control device, at the time of engine start, sets the second carrier frequency to be lower as the temperature of the inverter is higher and / or as the temperature of the cooling water is higher. Drive unit.

3. 3. The drive device according to claim 1 or 2, when the engine is not starting and the operating point of the motor is within a predetermined region, the control device controls the inverter by the pulse width modulation control using the two-phase modulation mode and a third carrier frequency that is higher than the first carrier frequency and lower than the second carrier frequency. Drive unit.

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