Multi-phase Motor Angle Error Correction Without Dismounting

Solution Overview

Problem

Existing multi-phase rotary machine control systems require demounting of the motor from its structure to correct positioning errors of the rotation angle sensor, which is inefficient, especially when the electronic control unit is replaced or reassembled.

Innovation Solution

A multi-phase rotary machine control apparatus that includes a rotation angle sensor, current detector, and control unit, which calculates and corrects angle errors by adjusting voltage command values to zero the drive currents, allowing for angle error detection and correction without dismounting the rotary machine from its mounting structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the conventional method of correcting rotation angle sensor positioning error is used (shorting two phases and detecting motor position), then the correction value can be calculated, but the motor must be demounted from its mounting structure, which reduces productivity and increases loss of time

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoidcorrection calculation efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical demounting operation with an electrical control method. The control unit commands the power converter to supply specific drive currents to the coils, eliminating the need for mechanical disassembly while achieving the same correction calculation objective. This substitution allows correction to be performed with the motor mounted on the vehicle structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the motor's own drive system (power converter and coils) to perform the correction calculation. By controlling the motor to operate in specific states through electrical commands, the system achieves self-diagnosis and self-correction capability without requiring external mechanical intervention or demounting.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If the conventional method is used, then correction value can be obtained, but the process requires demounting the motor, which increases device complexity and difficulty of operation

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoidcorrection process simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical demounting operation with an electrical control method. The control unit commands the power converter to supply specific drive currents to the coils, eliminating the need for mechanical disassembly while achieving the same correction calculation objective. This substitution allows correction to be performed with the motor mounted on the vehicle structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the motor's own drive system (power converter and coils) to perform the correction calculation. By controlling the motor to operate in specific states through electrical commands, the system achieves self-diagnosis and self-correction capability without requiring external mechanical intervention or demounting.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If the conventional method is used, then correction value can be calculated, but both motor and ECU must be replaced together, which increases loss of time and reduces adaptability

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoidcomponent replacement flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system uses the motor's own drive system (power converter and coils) to perform the correction calculation. By controlling the motor to operate in specific states through electrical commands, the system achieves self-diagnosis and self-correction capability without requiring external mechanical intervention or demounting.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The correction method is designed to work with the motor-ECU assembly as a integrated system. The control unit can identify and correct positioning errors regardless of which specific component (motor or ECU) has the error, allowing flexible replacement of either component independently while maintaining correction capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8796963B2Multi-phase rotary machine control apparatus and electric power steering system using the same

Publication Date: 2014.08.05 DENSO CORP

AI summary

A multi-phase rotary machine control apparatus executes calculation processing of an angle error caused by position error in attaching a rotation angle sensor to a motor. The control apparatus sets d-axis and q-axis current command values to zero. A rotary shaft of the rotary machine is rotated externally. The control apparatus detects phase currents caused by a counter-electromotive force, converts phases and outputs voltage command values so that the current detection values become zero. The control apparatus calculates an angle error based on the voltage command values, and stores the angle error as an angle correction value. The control apparatus corrects a detection value of a rotation angle sensor by the stored angle correction value.