Device and method of 6-step controlling inverter of motor driving system

Patent metadata

Field	Value
Publication number	US-2016006381-A1
Application number	US-201414566583-A
Country	US
Kind code	A1
Filing date	Dec 10, 2014
Priority date	Jul 4, 2014
Publication date	Jan 7, 2016
Grant date	—

Abstract

A device and a method of 6-step controlling of an inverter of a motor driving system are provided. The device and method and apply a voltage to a motor by adopting a 6-step control scheme capable of maximally using an input voltage of the inverter to improve output efficiency of the inverter and the motor and thus improve fuel efficiency of an environmentally friendly vehicle.

First claim

What is claimed is:

1 . A device for 6-step controlling an inverter of a motor driving system, comprising:
a current command map configured to generate a d/q axis current command; a current controller configured to generate a voltage command using a difference component between a d/q axis current requested by the current command map and a d/q axis current actually measured by a current sensor; and an inverter 6-step controller configured to:
detect a voltage vector phase from a voltage command output from the current controller;
generate a switching frequency for 12-sample phase controlling using the detected voltage vector phase component; and
apply a voltage command that corresponds to each of vertexes of a hexagon of a voltage vector diagram corresponding to a maximum voltage use rate to an inverter using the generated frequencies.

2 . The device of claim 1 , wherein the inverter 6-step controller is further configured to:
calculate a switching frequency component for the 12-sample phase control using the voltage vector phase obtained through the voltage vector phase detection unit; detect a voltage vector phase using a voltage command output from the current controller; generate a high gain over voltage modulated output voltage by multiplying an output voltage of the current controller by a gain; generate the high gain over voltage modulated output voltage by 12 times per one period of a fundamental wave based on the switching frequencies for the 12-sample phase control; change a pulse width modulation (PWM) period to cause voltage vectors to be symmetric based on the vertexes to converge the actual voltage vector to the vertex of the hexagon of the voltage vector diagram, and adjust a voltage vector phase; and apply a voltage command that corresponds to the vertex of the hexagon of the voltage vector diagram to the inverter through minimum distance overmodulation control.

3 . The device of claim 2 , wherein the inverter 6-step controller is configured to switch one of the switching frequencies for the calculated 12-sample phase control or predetermined switching frequencies to an updated frequency signal.

4 . A method of 6-step controlling an inverter of a motor driving system, comprising:
generating, by a controller, a voltage command using a difference component between a d/q axis current requested by a current command map and an actually measured d/q axis current; detecting, by the controller, a voltage vector phase from the voltage command; and 6-step controlling an inverter by generating, by the controller, switching frequencies for 12-sample phase control using the detected voltage vector phase component, and applying a voltage command that corresponds to each of vertexes of a hexagon of a voltage vector diagram corresponding to a maximum voltage use rate using the generated frequencies to the inverter.

5 . A method of 6-step controlling an inverter of a motor driving system, comprising:
detecting, by a controller, a voltage vector phase from a specific voltage command; and 6-step controlling an inverter by generating, by the controller, switching frequencies for 12-sample phase control using the detected voltage vector phase component, and applying a voltage command that corresponds to each of vertexes of a hexagon of a voltage vector diagram corresponding to a maximum voltage use rate using the generated frequencies to the inverter.

6 . The method of claim 4 , wherein the 6-step controlling of the inverter includes:
when the voltage command that corresponds to each of the vertexes of the hexagon of the voltage vector diagram is applied to the inverter, generating, by the controller, a high gain over voltage modulated output voltage by multiplying an output voltage of a current controller by a gain; generating, by the controller, the high gain over voltage modulated output voltage by 12 times per one period of a fundamental wave based on the switching frequencies for the 12-sample phase control; changing, by the controller, a pulse width modulation (PWM) period to cause voltage vectors to be symmetric based on the vertexes to converge the actual voltage vector to the vertex of the hexagon of the voltage vector diagram, and adjusting a voltage vector phase; and applying, by the controller, a voltage command that corresponds to the vertex of the hexagon of the voltage vector diagram to the inverter through minimum distance overmodulation control.

7 . The method of claim 6 , wherein the minimum distance overmodulation control is performed to cause the voltage applied to the inverter to generate a waveform with the 6 steps to a square wave, and includes:
calculating, by the controller, a virtual vector value obtained by multiplying a voltage vector that corresponds to an inscribed circle of the hexagon of the voltage vector diagram indicating 100% of an inverter voltage use rate by a constant; and
virtually drawing a vertical line converged to the vertex of the hexagon indicating 110% or greater of the inverter voltage use rate from the virtual vector value.

8 . The method of claim 4 , wherein the 6-step controlling of the inverter further includes:
generating, by the controller, the switching frequencies for the 12-sample phase control; and determining, by the controller, whether to perform the 6-step control of the inverter based on whether the switching frequencies satisfy a 12-sample phase control condition.

9 . The method of claim 8 , wherein the 12-sample phase control condition is set based on a speed and a torque of a motor, and an input voltage of the inverter.

10 . The method of claim 8 , wherein when the 12-sample phase control condition is not satisfied, a PWM signal, which is a final output voltage signal for the inverter, is synchronized to a predetermined switching frequency to be used for the control of the inverter.

11 . The method of claim 8 , wherein when the 12-sample phase control condition is satisfied, a PWM signal, which is a final output voltage signal for the inverter, is synchronized to the switching frequencies for the 12-sample phase control to be used for the control of the inverter.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Park Hong Geuk
• Kwak Mushin
• Kim Sung Kyu
• Bae Su Hyun

Classifications

• H02P27/085

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

• H02M7/53873

  with digital control · CPC title

• H02P6/14 Primary

  Electronic commutators · CPC title

• F16H2059/366

  Engine or motor speed · CPC title

• H02M7/5395

  by pulse-width modulation · CPC title