Motor control device, electromechanical integrated unit, boost converter system, electric vehicle system, and motor control method

Patent metadata

Field	Value
Publication number	US-2024042867-A1
Application number	US-202118266307-A
Country	US
Kind code	A1
Filing date	Sep 29, 2021
Priority date	Dec 17, 2020
Publication date	Feb 8, 2024
Grant date	—

Abstract

A motor control device connected to a power converter that performs power conversion from DC power to AC power and controls driving of an AC motor that is driven by using the AC power includes a voltage command generation unit that generates a three-phase voltage command; and a gate signal generation unit that performs pulse width modulation on the three-phase voltage command and generates a gate signal for controlling an operation of the power converter, in which the voltage command generation unit adjusts the three-phase voltage command by using a zero-phase voltage based on a power factor of the AC power in an overmodulation region in which a modulation factor according to a voltage amplitude ratio between the DC power and the AC power exceeds a predetermined threshold value, and the gate signal generation unit generates the gate signal by performing pulse width modulation on the adjusted three-phase voltage command.

First claim

1 . A motor control device that is connected to a power converter that performs power conversion from DC power to AC power and controls driving of an AC motor that is driven by using the AC power, the device comprising:
a voltage command generation unit that generates a voltage command; and a gate signal generation unit that performs pulse width modulation on the voltage command and generates a gate signal for controlling an operation of the power converter, wherein the voltage command generation unit adjusts the voltage command by using a zero-phase voltage based on a power factor of the AC power in an overmodulation region in which a modulation factor according to a voltage amplitude ratio between the DC power and the AC power exceeds a predetermined threshold value, and the gate signal generation unit generates the gate signal by performing pulse width modulation on the adjusted voltage command by the voltage command generation unit.

2 . The motor control device according to claim 1 , wherein
the voltage command generation unit is capable of generating a first zero-phase voltage based on the voltage command and a second zero-phase voltage based on the power factor, in a normal region where the modulation factor is less than the threshold value, the voltage command generation unit outputs the voltage command adjusted using the first zero-phase voltage as the adjusted voltage command, and in the overmodulation region, the voltage command generation unit outputs the voltage command adjusted by using the second zero-phase voltage as the adjusted voltage command.

3 . The motor control device according to claim 2 , wherein
the voltage command is a three-phase voltage command, and the voltage command generation unit generates the first zero-phase voltage based on an average value of a maximum phase voltage command and a minimum phase voltage command among the three-phase voltage commands, and delays a third harmonic component of the three-phase voltage command by a phase corresponding to the power factor to generate the second zero-phase voltage.

4 . The motor control device according to claim 1 , wherein the threshold value is 1.15.

5 . The motor control device according to claim 1 , further comprising:
a carrier wave generation unit that generates a carrier wave; and a carrier wave frequency adjustment unit that adjusts a frequency of the carrier wave, wherein the gate signal generation unit generates the gate signal by performing pulse width modulation on the voltage command by using the carrier wave, and the carrier wave frequency adjustment unit changes the frequency of the carrier wave when a magnitude of voltage pulsation of a capacitor connected to the power converter in parallel with a DC power supply that supplies the DC power exceeds a predetermined upper limit value.

6 . The motor control device according to claim 1 , further comprising:
a current command generation unit that generates a d-axis current command and a q-axis current command according to a torque command; and a current control unit that calculates a d-axis voltage command and a q-axis voltage command based on the d-axis current command and the q-axis current command, wherein the voltage command generation unit generates the voltage command by converting the d-axis voltage command and the q-axis voltage command into a three-phase voltage command, and the current command generation unit generates the d-axis current command and the q-axis current command so that a d-axis current is energized in the AC motor when a magnitude of voltage pulsation of a capacitor connected to the power converter in parallel with a DC power supply that supplies the DC power exceeds a predetermined upper limit value.

7 . An electromechanical integrated unit comprising:
the motor control device according to claim 1 ; the power converter that is connected to the motor control device; the AC motor that is driven by the power converter; and a gear that transmits a rotational driving force of the AC motor, wherein the AC motor, the power converter, and the gear are integrated.

8 . A boost converter system comprising:
the motor control device according to claim 1 ; the power converter that is connected to the motor control device; the AC motor that is driven by the power converter; and a boost converter that boosts a voltage of the DC power.

9 . An electric vehicle system comprising:
the motor control device according to claim 1 ; the power converter that is connected to the motor control device; and the AC motor that is driven by the power converter, wherein the electric vehicle system travels by using a rotational driving force of the AC motor.

10 . A motor control method for controlling an operation of a power converter that performs power conversion from DC power to AC power and controlling driving of an AC motor that is driven by using the AC power, the method comprising:
generating a voltage command; adjusting the voltage command by using a zero-phase voltage based on a power factor of the AC power in an overmodulation region in which a modulation factor according to a voltage amplitude ratio between the DC power and the AC power exceeds a predetermined threshold value; and generating a gate signal for controlling an operation of the power converter by performing pulse width modulation on the adjusted voltage command.

11 . The motor control method according to claim 10 , comprising:
outputting, as the adjusted voltage command, the voltage command adjusted using the first zero-phase voltage based on the voltage command in a normal region where the modulation factor is less than the threshold value; and outputting, as the adjusted voltage command, the voltage command adjusted by using the second zero-phase voltage based on the power factor in the overmodulation region.

12 . The motor control method according to claim 11 , wherein
the voltage command is a three-phase voltage command, the first zero-phase voltage is generated based on an average value of a maximum phase voltage command and a minimum phase voltage command among the three-phase voltage commands, and a third harmonic component of the three-phase voltage command is delayed by a phase corresponding to the power factor to generate the second zero-phase voltage.

13 . The motor control method according to claim 10 , wherein the threshold value is 1.15.

14 . The motor control method according to claim 10 , further comprising:
generating a carrier wave; generating the gate signal by performing pulse width modulation on the adjusted voltage command by using the carrier wave; and changing a frequency of the carrier wave when a magnitude of voltage pulsation of a capacitor connected to the power converter in parallel with a DC power supply that supplies the DC power exceeds a predetermined upper limit value.

15 . The motor control method according to claim 10 , further comprising:
generating a d-axis current command and a q-axis current command according to a torque command; calculating a d-axis voltage command and a q-axis voltage command based on the d-axis current command and the q-axis current command; generating the voltage command by converting the d-axis voltage command and the q-axis voltage command into a three-phase voltage command; and generating the d-axis current command and the q-axis current command so that a d-axis current is energized in the AC motor when a magnitude of voltage pulsation of a capacitor connected to the power converter in parallel with a DC power supply that supplies the DC power exceeds a predetermined upper

Assignees

• Hitachi Astemo Ltd

Inventors

• Hara Takafumi
• Ajima Toshiyuki
• ITAKURA Kyoshiro
• Tokuyama Takeshi
• Araki Takahiro
• Aoyagi Shigehisa

Classifications

• B60L15/20 Primary

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title

• B60L15/007 Primary

  Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• B60L2210/40

  DC to AC converters · CPC title

• H02P27/08

  with pulse width modulation · CPC title