Dual-Winding Steering Motor Control for Torque Ripple Compensation
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Solution Overview
Problem
Existing electric power steering systems with dual motors face issues of torque ripple due to back electromotive force generated by control unit failures, which affect steering wheel operation and are difficult to address with added control circuits due to cost and size constraints.
Innovation Solution
A motor control device with dual winding steering motors and electronic control units that exchange failure information through CAN communication, using lookup tables and PI controllers to compensate for failures by selecting appropriate compensation values and performing feedback control to reduce torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a control circuit is added to prevent torque ripple, then torque ripple can be reduced, but cost and device size increase
Solution Approach 1:
The patent uses a lookup table that stores pre-calculated compensation values for different failure modes, effectively creating a simplified copy of the complex compensation calculation process. This allows the system to implement torque ripple compensation without adding complex real-time control circuits, as the compensation strategy is pre-determined and stored in memory.
Solution Approach 2:
The patent pre-calculates and stores compensation values for various failure modes in a lookup table before actual operation. When a failure occurs, the system simply retrieves the pre-prepared compensation value corresponding to the detected failure mode, eliminating the need for complex real-time calculation circuits and reducing device complexity while maintaining effective torque ripple compensation.
2Reliability
If one motor or control unit fails, then reliability decreases, but adding redundant control circuits increases cost and size
Solution Approach 1:
The patent implements a self-diagnosis and self-compensation mechanism where the control unit automatically detects failure modes through monitoring electrical parameters (current, voltage, resistance) and retrieves appropriate compensation values from the lookup table. This self-service approach maintains reliability without requiring additional redundant control circuits, as the existing control unit adapts to failures autonomously.
Solution Approach 2:
The patent changes the operational parameters of the motor control system by storing multiple sets of compensation values in the lookup table corresponding to different failure modes. When a failure is detected, the system switches to using the parameter set appropriate for that failure mode, allowing the same hardware to operate reliably under various failure conditions without physical redundancy.
3Reliability
If failure information is exchanged between control units through CAN communication, then reliability improves, but loss of time occurs during communication
Solution Approach 1:
The patent pre-identifies and stores all possible failure modes and their corresponding compensation strategies in the lookup table before actual operation. This preliminary preparation allows the control unit to immediately retrieve the appropriate compensation value upon detecting a failure, eliminating the need for time-consuming communication with other control units and reducing time loss while maintaining accurate failure detection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures safe and comfortable steering operation by maintaining normal motor output even when one motor or control unit fails, reducing torque ripple and ensuring smooth steering wheel operation.
Implementation Method 1
when a failure occurs due to a short in the control unit, an internally flowing current is generated, so that a back electromotive force induced in the motor is generated
Data Source
AI summary
Disclosed herein are a motor control device for a steering system and a motor control method using the same. The motor control device includes a dual winding steering motor unit generating a steering force and a steering reaction force and including a first driving module formed of a first winding and a second driving module formed of a second winding, and a first electronic control unit controlling an operation of the first driving module, and a second electronic control unit controlling an operation of the second driving module, on the basis of steering information obtained by a driver's steering wheel manipulation.