System and method for controlling inverter for driving motor

Patent metadata

Field	Value
Publication number	US-10483900-B2
Application number	US-201816132691-A
Country	US
Kind code	B2
Filing date	Sep 17, 2018
Priority date	Feb 21, 2018
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

A system for controlling an inverter may include a motor; then inverter including a plurality of switching elements turned on/off by a pulse width modulation signal, converting DC power into AC power according to on/off of the plurality of switching elements and providing the AC power to the motor; a current sensor for detecting and outputting a current provided to the motor; a rotation angle sensor for detecting and outputting a rotor angle of the motor; and a controller for performing duty determination control for determining a duty of the pulse width modulation signal on the basis of values detected by the current sensor and the rotation angle sensor and a torque command of the motor.

First claim

What is claimed is:

1. A system for controlling an inverter for driving a motor, the system comprising:
the motor;
the inverter including a plurality of switching elements turned on or off by a pulse width modulation (PWM) signal, converting DC power supplied thereto into AC power according to on or off of the plurality of switching elements and providing the AC power to the motor;
a current sensor for detecting and outputting a current provided to the motor;
a rotation angle sensor for detecting and outputting a rotor angle of the motor; and
a controller configured for performing a duty determination control for determining a duty of the pulse width modulation signal on a basis of values detected by the current sensor and the rotation angle sensor and a torque command of the motor, associating a time at which the duty determination control is performed with the pulse width modulation signal, and arbitrarily changing a time at which the duty determination control is performed by changing a point in time at which a section that the pulse width modulation signal is higher than a predetermined value appears depending on a random setting time.

2. The system according to claim 1 , wherein the controller is configured to change the point in time at which the section that the pulse width modulation signal is higher than the predetermined value appears depending on the random setting time while maintaining a cycle of the pulse width modulation signal.

3. The system according to claim 2 , wherein the controller is configured to perform the duty determination control at points in time before and after a rising edge of the pulse width modulation signal, which are separated from the rising edge, and a start time of one duty determination control is a time elapsed from a start time of two preceding duty determination controls by one cycle of the pulse width modulation signal.

4. The system according to claim 1 , wherein the controller comprises:
a random number generator for generating the random setting time;
a sampling unit engaged to the random number generator and sampling the values output from the current sensor and the rotation angle sensor at a sampling time determined using the random setting time generated by the random number generator to generate a current detection value and a rotation angle detection value;
a current controller engaged to the sampling unit and configured for generating a voltage command of each phase of the motor on a basis of the current detection value and the rotation angle detection value generated by the sampling unit and a current command corresponding to the torque command of the motor; and
a pulse width modulation signal generator engaged to the current controller and generating a pulse width modulation signal for controlling the on or off of the switching elements of the inverter to output a voltage of each phase corresponding to the voltage command, and changing a point in time corresponding to the section that the pulse width modulation signal is higher than the predetermined value depending on the random setting time.

5. The system according to claim 4 , wherein the random number generator limits a size of the random setting time on a basis of the cycle of the pulse width modulation signal and a time limit predetermined for the duty determination control.

6. The system according to claim 5 , wherein the random number generator limits the size of the random setting time according to the following expression,
( a cycle of the PWM×0.5)−(the time limit for the duty determination controp≥α

wherein α is the random setting time.

7. The system according to claim 5 , wherein a current command generator generates the current command corresponding to the torque command input from the outside thereof on a basis of the torque command.

8. The system according to claim 7 , wherein the current controller generates an actual current measurement value and compares the current command with the actual current measurement value to obtain a difference therebetween, and generates three-phase voltage commands of the motor.

9. A method for controlling an inverter for driving a motor, the method comprising:
determining a random setting time;
determining a sampling time depending on the random setting time and sampling a motor driving current detection signal and a motor rotor angle detection signal at the determined sampling time; and
generating a pulse width modulation (PWM) signal for controlling on or off of switching elements included in the inverter providing driving power to the motor on a basis of the sampled motor driving current detection signal and motor rotor angle detection signal and a torque command of the motor,
wherein a point in time at which a section that the pulse width modulation signal is higher than a predetermined value, generated in the generating of the pulse width modulation signal, appears is changed depending on the random setting time, and the sampling time is associated with the pulse width modulation signal.

10. The method according to claim 9 , wherein, in the generating of the pulse width modulation signal, the point in time at which the section that the pulse width modulation signal is higher than the predetermined value appears is changed depending on the random setting time while a cycle of the pulse width modulation signal is maintained.

11. The method according to claim 10 , wherein, in the generating of the pulse width modulation signal, a duty determination control including the sampling and the pulse width modulation signal generation is performed at points in time before and after a rising edge of the pulse width modulation signal, which are separated from the rising edge, and a start time of one duty determination control is a time elapsed from a start time of two preceding duty determination controls by one cycle of the pulse width modulation signal.

12. The method according to claim 9 , wherein, in the determining of the random setting time, a size of the random setting time is limited on a basis of a cycle of the pulse width modulation signal and a time limit predetermined for a duty determination control including the sampling and the pulse width modulation signal generation.

13. The method according to claim 12 , wherein, in the determining of the random setting time, the size of the random setting time is limited according to the following expression,
(the cycle of the PWM×0.5)−(the time limit for the duty determination control)≥α

wherein α is the random setting time.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Park Joo Young
• Kwak Mu Shin
• Hwang Jae Ho
• Bae Su Hyun
• Lee Yong Jae
• Kim Sung Kyu

Classifications

• H02P21/50

  Vector control arrangements or methods not otherwise provided for in H02P21/00- H02P21/36 · CPC title

• H02P6/10

  Arrangements for controlling torque ripple, e.g. providing reduced torque ripple · CPC title

• H02M7/53875 Primary

  with analogue control of three-phase output · CPC title

• H02P27/085 Primary

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• H02M7/48

  using discharge tubes with control electrode or semiconductor devices with control electrode · CPC title