Motor control unit, failure detecting method, and electric power steering apparatus and vehicle equipped with the same

Patent metadata

Field	Value
Publication number	US-10232875-B2
Application number	US-201515508742-A
Country	US
Kind code	B2
Filing date	Sep 1, 2015
Priority date	Sep 4, 2014
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

A motor control unit is provided that controls a motor with multi-system windings via motor driving circuits on winding systems based on a current command value including current detecting circuits to detect at least two-phase or more currents for each of the multi-system windings of the three-phase motor, three-phase/two-phase converting sections to convert the detected phase currents to two-phase currents for the multi-system windings, and a failure diagnosing section to perform a current-calculation of the two-phase currents converted to two-phase for the multi-system windings, and to perform a diagnosis failure by comparing a difference of current-calculated results between the multi-system windings and an accumulating value of the difference with respective thresholds.

First claim

The invention claimed is:

1. A motor control unit that controls a three-phase motor with multi-system motor windings via motor driving circuits for respective winding systems based on a current command value, comprising:
current detecting circuits to detect at least two-phase or more currents for respective said multi-system motor windings of said three-phase motor;
three-phase/two-phase converting sections to convert said detected three-phase currents detected by said current detecting circuits to two-phase currents for respective said multi-system motor windings; and
a failure diagnosing section to perform a current-calculation of said two-phase currents converted to two-phases by said three-phase/two-phase converting sections for respective said multi-system motor windings, and to perform a failure diagnosis by respectively comparing a difference of current-calculated results between said multi-system motor windings and an accumulated value of said difference with respective failure-judgment thresholds;
wherein said failure-judgment thresholds are determined based on said current command value,
wherein in a case that said failure diagnosing section detects a failure, said failure diagnosing section judges a deviation in a continuous-driving capable value based on said failure-judgment thresholds and transmits a quantity of said deviation to a superior system or a superior controller so that drivings in multi-systems which include a failure system are successively continued.

2. The motor control unit according to claim 1 , wherein said current-calculation is an addition or a subtraction for said two-phase currents.

3. The motor control unit according to claim 1 , wherein said current-calculation is a square-sum for said two-phase currents.

4. The motor control unit according to claim 1 , wherein said current-calculation is a square root of a square-sum for said two-phase currents.

5. A motor control unit that controls a three-phase motor with multi-system motor windings via motor driving circuits for respective winding systems based on a current command value, comprising:
current detecting circuits to detect at least two-phase or more currents for respective said multi-system motor windings of said three-phase motor; and
a failure diagnosing section to perform a current-calculation of said three-phase currents detected by said current detecting circuits for respective said multi-system motor windings, and to perform a failure diagnosis by respectively comparing a difference of current-calculated results between said multi-system motor windings and an accumulated value of said difference with respective failure-judgment thresholds;
wherein said failure-judgment thresholds are determined based on said current command value,
wherein in a case that said failure diagnosing section detects a failure, said failure diagnosing section judges a deviation in a continuous-driving capable value based on said failure-judgment thresholds and transmits a quantity of said deviation to a superior system or a superior controller so that drivings in multi-systems which include a failure system are successively continued.

6. The motor control unit according to claim 5 , wherein said current-calculation is a square-sum for said three-phase currents.

7. The motor control unit according to claim 5 , wherein said current-calculation is a square root of a square-sum for said three-phase currents.

8. A motor control unit that controls a three-phase motor with multi-system motor windings via motor driving circuits for respective winding systems based on a current command value, comprising:
current detecting circuits to detect at least two-phase or more currents for respective said multi-system motor windings of said three-phase motor;
three-phase/two-phase converting sections to convert said detected three-phase currents detected by said current detecting circuits to two-phase currents for respective said multi-system motor windings; and
a failure diagnosing section to perform a current-calculation of said two-phase currents converted to two-phases by said three-phase/two-phase converting sections for respective said multi-system motor windings, and to perform a failure diagnosis by respectively comparing a difference of current-calculated results between said multi-system motor windings and an accumulated value of said difference with respective failure-judgment thresholds;
wherein said failure-judgment thresholds are determined based on said current command value,
wherein in a case that said failure diagnosing section detects a failure, said failure diagnosing section transmits said failure detection to a superior system or a superior controller and switches-OFF driving of a failure system so that only normal systems are continuously driven.

9. A motor control unit that controls a three-phase motor with multi-system motor windings via motor driving circuits for respective winding systems based on a current command value, comprising:
current detecting circuits to detect at least two-phase or more currents for respective said multi-system motor windings of said three-phase motor; and
a failure diagnosing section to perform a current-calculation of said three-phase currents detected by said current detecting circuits for respective said multi-system motor windings, and to perform a failure diagnosis by respectively comparing a difference of current-calculated results between said multi-system motor windings and an accumulated value of said difference with respective failure-judgment thresholds;
wherein said failure-judgment thresholds are determined based on said current command value,
wherein in a case that said failure diagnosing section detects a failure, said failure diagnosing section transmits said failure detection to a superior system or a superior controller and switches-OFF driving of a failure system so that only normal systems are continuously driven.

10. An electric power steering apparatus is equipped with the motor control unit according to claim 1 , and applies an assist force to a steering system of a vehicle due to a current command value calculated based on at least steering torque.

11. A vehicle is equipped with the electric power steering apparatus according to claim 10 .

Assignees

• Nsk Ltd

Inventors

• Kikuchi Yusuke
• Kimura Gen
• Tu Zhipeng

Classifications

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• B62D5/04

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title

• H02P29/024

  Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load · CPC title

• H02P6/16

  Circuit arrangements for detecting position · CPC title

• B62D5/0463

  calculating assisting torque from the motor based on driver input · CPC title