Control device for ac rotary machine and control device for electric power steering

Patent metadata

Field	Value
Publication number	US-2021146991-A1
Application number	US-201716627933-A
Country	US
Kind code	A1
Filing date	Jul 31, 2017
Priority date	Jul 31, 2017
Publication date	May 20, 2021
Grant date	—

Abstract

A control device for an AC rotary machine includes: a DC power supply; an inverter; a magnetic flux generator; an angle detector; and a control arithmetic unit; wherein the control arithmetic unit is configured to: calculate, based on a positional relationship between a current path and the angle detector, a correction signal for correcting signal errors of a cosine signal and a sine signal, which are caused by a noise magnetic flux component due to at least one of a DC current flowing between the DC power supply and the inverter and multi-phase AC currents flowing between the inverter and armature windings; and control the inverter by using angle information obtained from values after the correction by the correction signal.

First claim

1 . A control device for an AC rotary machine, comprising:
a DC power supply; an inverter, which is configured to invert a DC voltage supplied from the DC power supply to AC voltages, and to apply the AC voltages to armature windings of the AC rotary machine; a magnetic flux generator configured to rotate in synchronization with a rotor of the AC rotary machine configured to be rotated by a rotating magnetic flux formed by multi-phase AC currents flowing through the armature windings, to thereby generate an angle detection magnetic flux for detecting a rotation angle of the AC rotary machine; an angle detector, which is used in a saturated state with respect to a main component direction of the angle detection magnetic flux, and is configured to detect a cosine signal and a sine signal, which are two components orthogonal to each other and form the angle detection magnetic flux; and a control calculator configured to control the inverter based on a current command directed to the AC rotary machine and angle information obtained from the cosine signal and the sine signal, wherein the control calculator is configured to:
calculate, based on a positional relationship between a current path and the angle detector, a correction signal for correcting signal errors of the cosine signal and the sine signal, which are caused by a noise magnetic flux component due to at least one of a DC current flowing between the DC power supply and the inverter or the multi-phase AC currents flowing between the inverter and the armature windings; and
control the inverter by using the angle information obtained from a corrected cosine signal and a corrected sine signal, which are values after the correction by the correction signal.

2 . The control device for an AC rotary machine according to claim 1 , wherein the control calculator comprises:
a correction signal calculator configured to use the correction signal so as to correct a signal error proportional to a noise magnetic flux component in a normal line direction of the angle detection magnetic flux out of the noise magnetic flux due to at least one of the DC current or the multi-phase AC currents, to thereby generate the corrected cosine signal and the corrected sine signal; an angle configured to generate the angle information as a corrected rotation angle based on the corrected cosine signal and the corrected sine signal; and a current controller configured to control the inverter based on the corrected rotation angle.

3 . The control device for an AC rotary machine according to claim 2 ,
wherein, when a number of pole pairs of the magnetic flux generator is m (m is a natural number), a signal error caused by a noise magnetic flux of 0th order rotation due to the DC current contains a 0th order rotation component and a 2mth order rotation component, and wherein the correction signal calculator is configured to use the correction signal corresponding to the noise magnetic flux due to the DC current, a phase and an amplitude of which are determined by a phase correction constant and an amplitude correction constant determined by an arrangement of the angle detector, to thereby generate the corrected cosine signal and the corrected sine signal.

4 . The control device for an AC rotary machine according to claim 3 ,
wherein the angle detector is arranged at such an installation position that a direction of a magnetic flux generated by the DC current at a position of the angle detector on an XY plane is an X-axis direction or a Y-axis direction of the angle detector, and wherein the correction signal calculator is configured to calculate the correction signal corresponding to the noise magnetic flux caused by the DC current under satisfaction of a condition that the angle detector is arranged at the installation position.

5 . The control device for an AC rotary machine according to claim 4 , wherein a main path of the DC current from the DC power supply to the inverter and a main path of the DC current from the inverter to the DC power supply are arranged so as to be symmetrical about an XZ plane or a YZ plane of the angle detector.

6 . The control device for an AC rotary machine according to claim 4 ,
wherein the inverter includes a first inverter and a second inverter, wherein a main path of the DC current from the DC power supply to the first inverter and a main path of the DC current from the DC power supply to the second inverter are arranged so as to be symmetrical about an XZ plane or a YZ plane of the angle detector, and wherein a main path from the first inverter to the DC power supply and a main path from the second inverter to the DC power supply are arranged so as to be symmetrical about the XZ plane or the YZ plane.

7 . The control device for an AC rotary machine according to claim 4 ,
wherein the inverter includes at least one of a first inverter or a second inverter, wherein a main path of the DC current from the DC power supply to the first inverter and a main path of the DC current from the second inverter to the DC power supply are arranged so as to be symmetrical about an XZ plane or a YZ plane of the angle detector, and wherein a main path from the DC power supply to the second inverter and a main path from the first inverter to the DC power supply are arranged so as to be symmetrical about the XZ plane or the YZ plane.

8 . The control device for an AC rotary machine according to claim 2 , further comprising a smoothing capacitor connected in parallel to the DC power supply between the DC power supply and the inverter, wherein the correction signal calculator is configured to calculate, based on an arrangement of the angle detector and the current path through which the DC current flows, the correction signal corresponding to the noise magnetic flux due to the DC current, a phase and an amplitude of which are determined by a phase correction constant and a amplitude correction constant.

9 . The control device for an AC rotary machine according to claim 2 ,
wherein, when a number of pole pairs of the AC rotary machine is n (n is a natural number), a signal error caused by a noise magnetic flux of nth order rotation due to the multi-phase AC currents contains at least one of a (n−2m)th order rotation component or a (n+2m)th order rotation component in addition to a nth order rotation component, and wherein the correction signal calculator is configured to calculate the correction signal corresponding to the noise magnetic flux due to the multi-phase AC currents, a phase and an amplitude of which are determined by the phase correction constant and the amplitude correction constant determined by the current path of the multi-phase AC currents flowing between the inverter and the armature windings and an arrangement of the angle detector.

10 . The control device for an AC rotary machine according to claim 9 ,
wherein the angle detector is arranged at such an installation position that amplitudes of and a phase difference between an X-axis component and a Y-axis component of a magnetic flux generated by the multi-phase AC currents at a position of the angle detector are the same and π/2, respectively, and wherein the correction signal calculator is configured to calculate the correction signal corresponding to the noise magnetic flux due to the multi-phase AC currents under satisfaction of a condition that the angle detector is arranged at the installation position.

11 . The control device for an AC rotary machine according to claim 9 ,
wherein the angle detector is arranged at such an installation position that a direction of a magnetic flux generated by the multi-phase AC currents at a position of the angle detector on a

Assignees

• Mitsubishi Electric Corp
• Mitsubishi Electric Corp 7

Inventors

• Furukawa Akira

Classifications

• H02P6/10 Primary

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

• H02P27/08

  with pulse width modulation · CPC title

• H02P21/05

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

• H02P21/22

  Current control, e.g. using a current control loop · CPC title

• B62D5/046 Primary

  Controlling the motor · CPC title