Motor control apparatus

Patent metadata

Field	Value
Publication number	US-9793840-B2
Application number	US-201514841946-A
Country	US
Kind code	B2
Filing date	Sep 1, 2015
Priority date	Sep 2, 2014
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A motor control apparatus includes a counter, a margin calculation portion, and a cycle set portion. The counter counts a total number of switching the current supply phase of the coils when the rotor is rotationally driven. A rotation angle of the rotor is detected on a basis of the number of switching. The margin calculation portion calculates a torque margin that is a difference between an output torque of the motor and a load torque acting on the motor. The cycle set portion sets a current supply switching cycle to shorten as the torque margin is greater. The current supply switching cycle is a cycle switching the current supply phase of the coils.

First claim

What is claimed is:

1. A motor control apparatus controlling a synchronous motor including a stator that has a plurality of phases of coils and a rotor that rotates upon receiving a magnetic force caused by a rotation magnetic field generated by sequentially switching a current supply phase of the coils, the motor control apparatus comprising:
a microcomputer configured to include:
(i) a counter counting a total number of switching the current supply phase of the coils when the rotor is rotationally driven, wherein a rotation angle of the rotor is detected on a basis of the number of switching;
(ii) a margin calculation portion calculating a torque margin that is a difference between an output torque of the motor and a load torque acting on the motor; and
(iii) a cycle set portion setting a current supply switching cycle to shorten as the torque margin is greater, wherein the current supply switching cycle is a cycle switching the current supply phase of the coils, wherein:

the cycle portion decides a next value of the current supply switching cycle, the next value of the current supply switching cycle being decided by dividing a present value of the current supply switching cycle by the torque margin; and
the motor control apparatus does not use an encoder.

2. The motor control apparatus according to claim 1 , wherein:
a current variation is a variation of a current value flowing in the coils during current supply per a predetermined time; and
when the current variation is greater than a predetermined first threshold, the motor control apparatus extends the current supply switching cycle.

3. The motor control apparatus according to claim 2 , wherein:
a predetermined second threshold is a value greater than the predetermined first threshold; and
when the current variation is greater than the predetermined second threshold, the motor control apparatus determines that the motor steps out.

4. The motor control apparatus according to claim 1 , wherein:
a switching-time current value is the current value flowing in the coils during current supply at a time when the current supply switching cycle elapses and the current supply phases of the coils are switched;
a required current value is calculated by the motor control apparatus on a basis of the load torque; and
when the switching-time current value is less than the required current value, the motor control apparatus extends the current supply switching cycle.

Assignees

• Denso Corp

Inventors

• Tarui Jun

Classifications

• H02P6/08

  Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence) · CPC title

• H02P6/002

  Electricity · mapped topic

• H02P6/18 Primary

  without separate position detecting elements · CPC title

• H02P6/28

  Arrangements for controlling current (H02P6/10 takes precedence) · CPC title