Drive device

Abstract

To provide a drive device capable of securing an operating range in which harmonic superposition control can be executed by securing a motor rotation speed range in which PWM control can be executed.SOLUTION: A drive device according to the present invention includes a DC power supply, a boost converter that boosts the voltage of the DC power supply, an inverter that converts the DC power supply voltage boosted by the boost converter into an AC voltage, a motor that drives a vehicle using the AC voltage converted by the inverter, and a control device that controls the boost converter in accordance with the torque command and rotation speed of the motor, and the control device boosts the voltage of the DC power supply by controlling the boost converter when switching between executing and stopping harmonic superposition control, and selects a boost value between a maximum value and a normal value on the basis of the motor rotation speed and the rate of change of the rotation speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 describes a motor control device that can perform harmonic superposition control, which superimposes harmonics on a command signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-195390 Summary of the Invention [Problem to be solved by the invention]

[0004] To perform harmonic superposition control, it is necessary to increase the carrier frequency using PWM control. Therefore, when the motor is in a high-torque or high-speed state, which increases the voltage utilization rate and makes PWM control impossible, it is necessary to prohibit the execution of harmonic superposition control. However, in situations where the motor rotation speed increases rapidly, the discrepancy between the detected motor rotation speed and the actual value can delay the determination that the motor rotation speed has exceeded the predetermined rotation speed, which can delay the prohibition of harmonic superposition control. For this reason, there has been a demand for technology that can ensure a motor rotation speed range in which PWM control can be performed, thereby ensuring a range in which harmonic superposition control can be performed.

[0005] The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a drive device that can ensure an operating range in which harmonic superposition control can be performed by ensuring a motor rotation speed range in which PWM control can be performed. [Means for solving the problem]

[0006] The drive device of the present invention comprises a DC power supply, a boost converter that boosts the voltage of the DC power supply, an inverter that converts the voltage of the DC power supply boosted by the boost converter into an AC voltage, a motor that drives a vehicle using the AC voltage converted by the inverter, and a control device that controls the boost converter in accordance with a torque command and rotation speed of the motor, wherein the control device boosts the voltage of the DC power supply by controlling the boost converter when switching between executing and stopping harmonic superposition control, and selects a boost value between a maximum value and a normal value based on the rotation speed of the motor and the rate of change of that rotation speed. [Effects of the Invention]

[0007] According to the drive device of the present invention, a region in which harmonic superposition control can be performed can be secured by securing a motor rotation speed region in which PWM control can be performed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a vehicle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the flow of a boost voltage command calculation routine according to one embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart showing the flow of an inverter control routine according to one embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart showing the flow of a modified example of the boost voltage command calculation routine according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the configuration of a vehicle according to one embodiment of the present invention will be described with reference to the drawings.

[0010] Fig. 1 is a block diagram showing the configuration of a vehicle according to one embodiment of the present invention. As shown in Fig. 1, vehicle 1 according to one embodiment of the present invention includes, as a drive device, a DC power supply 11, a boost converter 12 that boosts the voltage of DC power supply 11, an inverter 13 that converts the voltage of DC power supply 11 boosted by boost converter 12 into an AC voltage, a motor 14 that drives vehicle 1 using the AC voltage converted by inverter 13, and an ECU 15 that controls boost converter 12 according to a torque command and rotation speed of motor 14.

[0011] In the vehicle 1 having such a configuration, the ECU 15 executes a boost voltage command calculation routine and an inverter control routine described below to ensure a rotation speed range of the motor 14 in which PWM control can be performed, thereby ensuring a range in which harmonic superposition control can be performed. Hereinafter, the operation of the ECU 15 when executing the boost voltage command calculation routine and the inverter control routine will be described with reference to Figures 2 and 3.

[0012] [Boost voltage command calculation routine] 2 is a flowchart showing the flow of a boost voltage command calculation routine according to one embodiment of the present invention. The flowchart shown in FIG. 2 starts when an execution command for the boost voltage command calculation routine is input to the ECU 15, and the boost voltage command calculation routine proceeds to processing in step S11.

[0013] In the process of step S1, the ECU 15 determines whether the rotation speed Nm of the motor 14 is less than a predetermined rotation speed Nmref. If the determination result shows that the rotation speed Nm of the motor 14 is less than the predetermined rotation speed Nmref (step S1: Yes), the ECU 15 advances the step-up voltage command calculation routine to the process of step S2. On the other hand, if the rotation speed Nm of the motor 14 is equal to or greater than the predetermined rotation speed Nmref (step S1: No), the ECU 15 advances the step-up voltage command calculation routine to the process of step S3.

[0014] In the process of step S2, the ECU 15 determines whether the rate of change ΔNm of the rotation speed Nm of the motor 14 is greater than a predetermined rate of change ΔNmref. If the result of the determination is that the rate of change ΔNm of the rotation speed Nm of the motor 14 is greater than the predetermined rate of change ΔNmref (step S2: Yes), the ECU 15 advances the step-up voltage command calculation routine to the process of step S3. On the other hand, if the rate of change ΔNm of the rotation speed Nm of the motor 14 is equal to or less than the predetermined rate of change ΔNmref (step S2: No), the ECU 15 advances the step-up voltage command calculation routine to the process of step S4.

[0015] In the process of step S3, ECU 15 sets the boost command value for boost converter 12 to the maximum value Vmax, thereby completing the process of step S3 and ending the series of boost voltage command calculation routines.

[0016] In the process of step S4, ECU 15 sets the boost command value for boost converter 12 to normal value Vref (<maximum value Mmax), thereby completing the process of step S4 and ending the series of boost voltage command calculation routines.

[0017] [Inverter control routine] 3 is a flowchart showing the flow of an inverter control routine according to one embodiment of the present invention. The flowchart shown in FIG. 3 starts when an instruction to execute the inverter control routine is input to the ECU 15, and the inverter control routine proceeds to processing in step S11.

[0018] In the process of step S11, the ECU 15 calculates the phase currents Iv and Im of the motor 14, the electrical angle θe, the rotation speed Nm, and the torque command Tm * This completes the process of step S11, and the inverter control routine proceeds to the process of step S12.

[0019] In the process of step S12, the ECU 15 calculates the rate of change ΔNm of the rotation speed Nm of the motor 14. This completes the process of step S12, and the inverter control routine proceeds to the process of step S13.

[0020] In the process of step S13, the ECU 15 coordinate-converts the phase currents Iv and Im of the motor 14 acquired in the process of step S11 into d-axis and q-axis current commands Id and Iq using the electrical angle θe of the motor 14 acquired in the process of step S11. This completes the process of step S13, and the inverter control routine proceeds to the process of step S14.

[0021] In the process of step S14, the ECU 15 determines whether the rotation speed Nm of the motor 14 acquired in the process of step S11 is less than a predetermined rotation speed Nmref. If the result of the determination is that the rotation speed Nm of the motor 14 is less than the predetermined rotation speed Nmref (step S14: Yes), the ECU 15 advances the inverter control routine to the process of step S15. On the other hand, if the rotation speed Nm of the motor 14 is equal to or greater than the predetermined rotation speed Nmref (step S14: No), the ECU 15 advances the inverter control routine to the process of step S24.

[0022] In the process of step S15, the ECU 15 permits the execution of harmonic superposition control, which completes the process of step S16, and the inverter control routine proceeds to the process of step S16.

[0023] In the process of step S16, the ECU 15 calculates the torque command Tm of the motor 14 obtained in the process of step S11. * Then, the processing of step S16 is completed, and the inverter control routine proceeds to the processing of step S17.

[0024] In the process of step S17, the ECU 15 calculates the electrical angle θe, the rotation speed Nm, and the torque command Tm of the motor 14 obtained in the process of step S11. *Then, the process of step S17 is completed, and the inverter control routine proceeds to the process of step S18.

[0025] In the process of step S18, the ECU 15 adds the d-axis and q-axis harmonic superimposed current commands Idh and Iqh set in the process of step S17 to the d-axis and q-axis basic current commands Idbs and Iqbs set in the process of step S16, thereby obtaining the d-axis and q-axis current commands Id * ,Iq * This completes the process of step S18, and the inverter control routine proceeds to the process of step S19.

[0026] In the process of step S19, the ECU 15 compares the d-axis and q-axis current commands Id and Iq obtained in the process of step S13 with the d-axis and q-axis current commands Id and Iq set in the process of step S18. * ,Iq * Then, the process of step S19 is completed, and the inverter control routine proceeds to the process of step S20.

[0027] In the process of step S20, the ECU 15 calculates the electrical angle θe, the rotation speed Nm, and the torque command Tm of the motor 14 obtained in the process of step S11. * The d-axis and q-axis voltage command FF terms Vdff, Vqff are set using the following equation: This completes the process of step S20, and the inverter control routine proceeds to the process of step S21.

[0028] In the process of step S21, the ECU 15 adds the d-axis and q-axis voltage command FF terms Vdff and Vqff set in the process of step S20 to the d-axis and q-axis voltage command FB terms Vdfb and Vqfb calculated in the process of step S19, thereby obtaining the d-axis and q-axis voltage commands Vd * ,Vq * This completes the process of step S21, and the inverter control routine proceeds to the process of step S22.

[0029] In the process of step S22, the ECU 15 calculates the d-axis and q-axis voltage commands Vd calculated in the process of step S21 or step S29 using the electrical angle θe of the motor 14 obtained in the process of step S11. * ,Vq * The voltage command Vu of the U, V, and W phases * ,Vv * ,Vw * This completes the process of step S22, and the inverter control routine proceeds to the process of step S23.

[0030] In the process of step S23, the ECU 15 calculates the voltage commands Vu of the U-phase, V-phase, and W-phase obtained in the process of step S22. * ,Vv * ,Vw * This completes the process of step S23, and the inverter control routine ends.

[0031] In the process of step S24, the ECU 15 permits the execution of harmonic superposition control, which completes the process of step S24, and the inverter control routine proceeds to the process of step S25.

[0032] In the process of step S25, the ECU 15 calculates the torque command Tm of the motor 14 obtained in the process of step S11. * Then, the processing of step S25 is completed, and the inverter control routine proceeds to the processing of step S26.

[0033] In the process of step S26, the ECU 15 converts the d-axis and q-axis basic current commands Idbs and Iqbs set in the process of step S25 into the d-axis and q-axis current commands Id * ,Iq * This completes the process of step S26, and the inverter control routine proceeds to the process of step S27.

[0034] In the process of step S27, the ECU 15 compares the d-axis and q-axis current commands Id and Iq obtained in the process of step S13 with the d-axis and q-axis current commands Id and Iq set in the process of step S26. * ,Iq * Then, the process of step S27 is completed, and the inverter control routine proceeds to the process of step S28.

[0035] In the process of step S28, the ECU 15 calculates the torque command Tm of the motor 14 obtained in the process of step S11. * The d-axis and q-axis voltage command FF terms Vdff, Vqff are set using the following equation: This completes the processing of step S28, and the inverter control routine proceeds to the processing of step S29.

[0036] In the process of step S29, the ECU 15 adds the d-axis and q-axis voltage command FF terms Vdff and Vqff set in the process of step S28 to the d-axis and q-axis voltage command FB terms Vdfb and Vqfb calculated in the process of step S27, thereby obtaining the d-axis and q-axis voltage commands Vd * ,Vq * This completes the process of step S29, and the inverter control routine proceeds to the process of step S22.

[0037] As is clear from the above description, in vehicle 1, which is one embodiment of the present invention, ECU 15 controls boost converter 12 when switching between executing and stopping harmonic superposition control to boost the voltage of DC power supply 11, and selects a boost value between the maximum value and the normal value based on the rotation speed and rate of change of rotation speed of motor 14. With this configuration, the voltage utilization rate can be reduced by boosting the power supply voltage through boost control, and therefore a region in which harmonic superposition control can be executed can be secured by securing a motor rotation speed region in which PWM control can be executed.

[0038] [Modification] 4 is a flowchart showing the flow of a modified example of the boost voltage command calculation routine according to one embodiment of the present invention. The flowchart shown in FIG. 4 starts when an execution command for the boost voltage command calculation routine is input to the ECU 15, and the boost voltage command calculation routine proceeds to processing in step S31.

[0039] In the process of step S31, the ECU 15 determines whether the rotation speed Nm of the motor 14 is less than a predetermined rotation speed Nmref. If the determination result shows that the rotation speed Nm of the motor 14 is less than the predetermined rotation speed Nmref (step S31: Yes), the ECU 15 advances the step-up voltage command calculation routine to the process of step S32. On the other hand, if the rotation speed Nm of the motor 14 is equal to or greater than the predetermined rotation speed Nmref (step S31: No), the ECU 15 advances the step-up voltage command calculation routine to the process of step S35.

[0040] In the process of step S32, the ECU 15 determines whether the rate of change ΔNm of the rotation speed Nm of the motor 14 is greater than a predetermined rate of change ΔNmref. If the result of the determination is that the rate of change ΔNm of the rotation speed Nm of the motor 14 is greater than the predetermined rate of change ΔNmref (step S32: Yes), the ECU 15 advances the step-up voltage command calculation routine to the process of step S33. On the other hand, if the rate of change ΔNm of the rotation speed Nm of the motor 14 is equal to or less than the predetermined rate of change ΔNmref (step S32: No), the ECU 15 advances the step-up voltage command calculation routine to the process of step S35.

[0041] In the process of step S33, the ECU 15 calculates the torque command Tm * and the rotation speed Nm, the minimum boost lower limit voltage Vlo required to maintain PWM control is calculated. The boost lower limit voltage Vlo is calculated by taking into account the increase in the voltage utilization rate due to variations in inverter dead time and VH sensor error, etc., and is calculated by subtracting the torque command Tm of the motor 14 from the minimum boost lower limit voltage Vlo. * and the rotation speed Nm. This completes the process of step S33, and the boost voltage command calculation routine proceeds to the process of step S34.

[0042] In the process of step S34, the ECU 15 sets the boost command value to the larger of the boost lower limit voltage Vlo calculated in the process of step S33 and the maximum value Vmax of the boost command value for the boost converter 12. This completes the process of step S34, and the series of boost voltage command calculation routines ends.

[0043] In the process of step S35, ECU 15 sets the boost command value for boost converter 12 to normal value Vref, thereby completing the process of step S35 and ending the series of boost voltage command calculation routines.

[0044] Although the present invention has been described above as an embodiment, the present invention is not limited to the description and drawings that form part of the disclosure of the present invention. In other words, other embodiments, examples, and operational techniques that can be made by those skilled in the art based on the present invention are all included in the scope of the present invention. [Explanation of symbols]

[0045] 1 vehicle 11 DC power supply 12 Boost Converter 13 Inverter 14 Motor 15 ECU

Claims

[Claim 1] A DC power supply; a boost converter that boosts the voltage of the DC power supply; an inverter that converts the voltage of the DC power supply boosted by the boost converter into an AC voltage; a motor that drives a vehicle using the AC voltage converted by the inverter; a control device that controls the boost converter in accordance with a torque command and a rotation speed of the motor; Equipped with the control device controls the boost converter when switching between execution and stop of harmonic superposition control to boost the voltage of the DC power supply, and selects a boost value between a maximum value and a normal value based on the rotation speed of the motor and a rate of change of the rotation speed. Drive unit.

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