Controller for permanent magnet synchronous motor, and control method for estimating initial position of rotor

Patent metadata

Field	Value
Publication number	US-10141878-B2
Application number	US-201715813690-A
Country	US
Kind code	B2
Filing date	Nov 15, 2017
Priority date	Dec 8, 2016
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A controller for a sensorless permanent magnet synchronous motor having a rotor using a permanent magnet, the rotor rotating by a rotating magnetic field caused by a current flowing through an armature is provided. The controller is configured to apply a pulse voltage for generating a magnetic field vector for searching for the initial position to each of search sections obtained by dividing a target range, narrow down a target range in such a manner that a search section in which a largest amount of current flows through the armature by application of the pulse voltage is selected as a subsequent target range, and repeat the application processing and the narrow-down processing to estimate the initial position.

First claim

What is claimed is:

1. A controller for a sensorless permanent magnet synchronous motor having a rotor using a permanent magnet, the rotor rotating by a rotating magnetic field caused by a current flowing through an armature, the controller comprising:
a drive portion configured to apply a voltage to the armature to drive the rotor;
an initial position estimating portion configured to estimate an initial position which is a position of magnetic poles of the rotor which is in a stop state; and
a control unit configured to control the drive portion; wherein
the initial position estimating portion gives instructions to the control unit to apply a pulse voltage for generating a magnetic field vector for searching for the initial position to each of search sections obtained by dividing a target range narrows down a target range in such a manner that a search section in which a largest amount of current flows through the armature by application of the pulse voltage is selected as a subsequent target range, and estimates the initial position.

2. The controller for the sensorless permanent magnet synchronous motor according to claim 1 , wherein the initial position estimating portion gives instructions to the control unit to apply a pulse voltage so that, in narrowing down the target range, a magnetic field vector for preventing rotation is generated in a non-target range which is not the target range.

3. The controller for the sensorless permanent magnet synchronous motor according to claim 2 , wherein the initial position estimating portion gives instructions to the control unit to generate the magnetic field vector for preventing rotation while the magnetic field vector for searching is generated in each of the search sections in order.

4. The controller for the sensorless permanent magnet synchronous motor according to claim 2 , wherein a direction of the magnetic field vector for preventing rotation is a direction shifted, by an electrical angle of 180°, with respect to a direction of the magnetic field vector for searching generated in the search section, or, is a direction close to the direction.

5. The controller for the sensorless permanent magnet synchronous motor according to claim 2 , wherein a direction of the magnetic field vector for preventing rotation is a direction shifted, by an electrical angle of 180°, with respect to an angular position in a middle of the target range.

6. The controller for the sensorless permanent magnet synchronous motor according to claim 1 , wherein the initial position estimating portion gives instructions to the control unit to generate a magnetic field vector for preventing rotation only in a step before the target range is narrowed down to a set size.

7. The controller for the sensorless permanent magnet synchronous motor according to claim 1 , wherein, when a difference between the currents of the search sections where the magnetic field vector for searching is generated in each of the search sections is equal to or smaller than a threshold, the initial position estimating portion gives instructions to the control unit to change the current target range to a range where an angular position of the current target range is shifted, and to generate the magnetic field vector for searching in each of search sections obtained by dividing a post-change target range.

8. The controller for the sensorless permanent magnet synchronous motor according to claim 1 , wherein the initial position estimating portion estimates the initial position based on a value of the current at a point in time when a set time equal to or shorter than an application time of the pulse voltage has elapsed since a rising edge of the pulse voltage.

9. The controller for the sensorless permanent magnet synchronous motor according to claim 1 , wherein the initial position estimating portion estimates the initial position based on a time from a rising edge of the pulse voltage to a reach to a set value of a value of the current.

10. A control method for estimating an initial position of a rotor in a sensorless permanent magnet synchronous motor, the control method comprising:
estimating an initial position by repeatedly performing processing for applying a pulse voltage for generating a magnetic field vector for searching for the initial position to each of search sections obtained by dividing a target range which is an angular position range to be searched in an armature and processing for narrowing down a target range in such a manner that a search section in which a largest amount of current flows through the armature by application of the pulse voltage is selected as a subsequent target range.

11. The control method for estimating the initial position according to claim 10 , wherein, in narrowing down the target range, a pulse voltage is applied so that a magnetic field vector for preventing rotation is generated in a non-target range which is not the target range.

Assignees

• Konica Minolta Inc

Inventors

• Suzuki Daichi
• Tachibana Yuta
• Yoshikawa Hiroyuki
• Koide Yasuhiro

Classifications

• H02P21/18 Primary

  Estimation of position or speed · CPC title

• H02P6/186

  using difference of inductance or reluctance between the phases · CPC title

• H02P6/185

  using inductance sensing, e.g. pulse excitation · CPC title

• H02P6/17

  and for generating speed information · CPC title

• H02P21/34

  Arrangements for starting · CPC title