Inductance measuring device and measuring method for synchronous motor

Patent metadata

Field	Value
Publication number	US-9335356-B2
Application number	US-201013884486-A
Country	US
Kind code	B2
Filing date	Dec 6, 2010
Priority date	Dec 6, 2010
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

[Problem]
For measuring the inductance of a synchronous motor, a high-speed and convenient inductance measuring device for a synchronous motor is provided.
[Solution]
A three-phase high-frequency rotation voltage is applied to a synchronous motor, thereby calculating the inductance from the same frequency component as that of the high-frequency voltage included in a motor current.

First claim

What is claimed is:

1. An inductance measuring device for a synchronous motor comprising:
a voltage signal generator for generating a high-frequency voltage signal to be inputted to a voltage converter;
a voltage converter for converting the high-frequency voltage signal to apply to the synchronous motor;
a current detector for detecting a current of the synchronous motor;
a coordinate converter for converting the current detected by the current detector into a current on an orthogonal biaxial coordinate system positioned in an arbitrary phase with respect to a fixed coordinate system, to output a current in one axis of the orthogonal biaxial coordinate system;
a fundamental wave component extractor for extracting the same frequency component as that of the high-frequency voltage included in the current in the one axis of the orthogonal biaxial coordinate system; and
an inductance calculator for calculating an inductance from a root-mean-square value and a frequency of the high-frequency voltage, and an output from the fundamental wave component extractor,
wherein, in the generating the high-frequency voltage signal, the voltage signal generator generates a variable voltage root-mean-square value, and a three-phase high-frequency rotation voltage signal having a frequency, as a fundamental frequency, sufficiently higher compared with the maximum value of a rotation frequency at which the synchronous motor can synchronously rotate, and outputs the variable voltage root-mean-square value and the three-phase high-frequency rotation voltage signal to the voltage converter as the high-frequency voltage signal.

2. The inductance measuring device for the synchronous motor as recited in claim 1 , wherein the fixed coordinate system of the coordinate converter is a coordinate system composed of a u axis, a v axis, and a w axis, and the orthogonal biaxial coordinate system is composed of a y axis and δ axis, in which the current in the one axis of the orthogonal biaxial coordinate system is a y axis current.

3. The inductance measuring device for the synchronous motor as recited in claim 1 , wherein the coordinate converter obtains, by converting from the fixed coordinate system to the orthogonal biaxial coordinate system at least at an electrical angle of 180 degrees, a d-axis inductance and a q-axis inductance of the synchronous motor from the minimum value and the maximum value of the inductance calculator.

Assignees

• Adachi Shoji
• Kinpara Yoshihiko
• Mitsubishi Electric Corp

Inventors

• Adachi Shoji
• Kinpara Yoshihiko

Classifications

• H02P21/16 Primary

  Estimation of constants, e.g. the rotor time constant · CPC title

• G01R27/2611 Primary

  Measuring inductance · CPC title

• H02P21/145

  Electricity · mapped topic

• H02P21/00 Primary

  Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation · CPC title

• H02P27/04

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