Apparatus for controlling three phase rotary electric machine reducing peak value of phase current

Patent metadata

Field	Value
Publication number	US-9979340-B2
Application number	US-201715628404-A
Country	US
Kind code	B2
Filing date	Jun 20, 2017
Priority date	Jun 22, 2016
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

A control apparatus for driving a three-phase rotary electric machine that generates torque including magnet torque and reluctance torque is provided. AC current supplied to two winding groups of the rotary electric machine have the same amplitude and the mutually different phases defined as 30±60×n[deg]. The control unit calculates d-axis current and q-axis current of 6 (2k+1)th order component superposed on a fundamental wave component on dq coordinate, to reduce a peak of the first order component in the phase current, thereby controlling the three-phase rotary electric machine. The control unit calculates current such that an amplitude of the q-axis current of the 6 (2k+1)th order component is larger than an amplitude of the d-axis current of the 6 (2k+1)th order component.

First claim

What is claimed is:

1. A control apparatus for driving a three-phase rotary electric machine having two three-phase winding groups, the three-phase rotary electric machine generating torque which is a sum of magnet torque and reluctance torque when AC current having mutually different phases is conducted through the two winding groups, the control apparatus comprising:
two power converters each provided for a corresponding one of two winding groups, each power converter supplying AC current to each of the two winding groups, the AC current supplied to the two winding groups have the same amplitude and the mutually different phases defined as 30±60×n[deg], where n is integer number; and
a control unit configured to calculate d-axis current and q-axis current of 6 (2k+1)th order component superposed on a fundamental wave component on a dq coordinate, where k=0 or more integer number, so as to reduce a peak value of a first order component in phase current conducted in the two winding groups, thereby controlling conduction of the three-phase rotary electric machine, wherein
the control unit is configured to calculate current such that an amplitude of the q-axis current of the 6 (2k+1)th order component is larger than an amplitude of the d-axis current of the 6 (2k+1)th order component.

2. The control apparatus according to claim 1 , wherein
the control unit is configured to set an amplitude of the d-axis current of the 6 (2k+1)th order component to be 0.

3. The control apparatus according to claim 1 , wherein
the control unit further includes a torque ripple compensation amount calculator that calculates a compensation amount of a torque ripple of 12 (2k+1)th order component produced based on a product of amplitudes of the d-axis current and the q-axis current of the 6 (2k+1) th order component; and
the control unit adds the compensation amount of the torque ripple to the q-axis current, the compensation amount of the torque ripple being calculated by the torque ripple compensation amount calculator.

4. The control apparatus according to claim 1 , wherein
the control apparatus is adapted for an electric power steering apparatus of a vehicle, and controls driving of a steering assist motor as the three-phase rotary electric machine.

Assignees

• Denso Corp

Inventors

• Suzuki Takashi

Classifications

• H02P21/05

  specially adapted for damping motor oscillations, e.g. for reducing hunting · CPC title

• H02P5/00

  Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors (H02P6/04, H02P8/40 take precedence) · CPC title

• H02P6/10

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

• H02P27/05

  using AC supply for both the rotor and the stator circuits, the frequency of supply to at least one circuit being variable · CPC title

• H02P27/04

  using variable-frequency supply voltage, e.g. inverter or converter supply voltage · CPC title