Drive unit of synchronous motor

Patent metadata

Field	Value
Publication number	US-9948223-B2
Application number	US-201214420948-A
Country	US
Kind code	B2
Filing date	Sep 3, 2012
Priority date	Sep 3, 2012
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Provided is drive unit of a synchronous motor capable of improving the accuracy of magnetic flux operations with a simple configuration. To this end, the drive unit has a magnetic flux operation part which, in the case where a direction of a magnetic field pole of the synchronous motor is regarded as a d-axis and a direction orthogonal to the d-axis is regarded as a q-axis, calculates a magnetic flux of the d-axis and a magnetic flux of the q-axis on the basis of a current of the d-axis, a current of the q-axis, and a field current of the synchronous motor; and a magnetic flux operation error correcting part which calculates a phase difference between an input voltage and an input current of the synchronous motor and corrects an inner-phase difference angle calculated from the magnetic flux of the d-axis and the magnetic flux of the q-axis on the basis of the phase difference.

First claim

The invention claimed is:

1. A drive unit of a synchronous motor comprising:
a magnetic flux operation circuitry configured to, in the case where a direction of a magnetic field pole of the synchronous motor is regarded as a d-axis and a direction orthogonal to the d-axis is regarded as a q-axis, calculate a magnetic flux of the d-axis and a magnetic flux of the q-axis on the basis of a current of the d-axis, a current of the q-axis, and a field current of the synchronous motor; and
a magnetic flux operation error correcting circuitry configured to
calculate a phase difference between a voltage and a current of the synchronous motor being inputted into the magnetic flux operation error correcting circuitry;
calculate an inner-phase difference angle from the magnetic flux of the d-axis and the magnetic flux of the q-axis, wherein the inner-phase difference angle=tan −1 X, where X=(the magnetic flux of the q-axis)/(the magnetic flux of the d-axis); and
correct the inner-phase difference angle on the basis of the phase difference, wherein

the drive unit is configured to drive the synchronous motor with the corrected inner-phase difference angle, and
the magnetic flux operation error correcting circuitry calculates a corrected magnetic flux of the q-axis on the basis of the magnetic flux of the d-axis, the magnetic flux of the q-axis, and the corrected inner-phase difference angle, wherein the corrected magnetic flux of the q-axis=√{square root over (A)}·sin B, where A=(the magnetic flux of the d-axis) 2 +(the magnetic flux of the q-axis) 2 , and B=the corrected inner-phase difference angle.

2. The drive unit of the synchronous motor according to claim 1 , wherein the magnetic flux operation error correcting circuitry calculates the phase difference on the basis of a voltage reference and a current detection value of the synchronous motor being inputted into the magnetic flux operation error correcting circuitry.

3. The drive unit of the synchronous motor according to claim 1 , wherein the magnetic flux operation error correcting circuitry calculates the phase difference on the basis of a voltage detection value and a current detection value of the synchronous motor being inputted into the magnetic flux operation error correcting circuitry.

Assignees

• Ishida Takashi
• Toshiba Mitsubishi Elec Ind

Inventors

• Ishida Takashi

Classifications

• H02P21/10 Primary

  Direct field-oriented control; Rotor flux feed-back control · CPC title

• H02P25/024

  controlled by supply frequency · CPC title

• H02P21/141 Primary

  Flux estimation · CPC title

• H02P6/06 Primary

  Arrangements for speed regulation of a single motor wherein the motor speed is measured and compared with a given physical value so as to adjust the motor speed · CPC title