Motor Control Device Switching Circuit for Torque Continuity
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Solution Overview
Problem
Existing motor control devices face issues with sudden changes in output torque and discontinuity of operation when switching from two-system drive to one-system drive due to microcomputer failures, particularly in electric power steering systems, leading to driver discomfort.
Innovation Solution
A motor control device with two systems, each comprising a power converter, microcomputer, monitoring circuit, and switching circuit group, where switching circuits select between own and other drive signals based on microcomputer status, ensuring continuous motor drive and minimizing torque changes by simplifying control switching and reducing lag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two microcomputers are redundantly provided to improve reliability, then the system can continue operation when one fails, but sudden torque changes and discontinuity occur during switching from two-system to one-system drive
Solution Approach 1:
The patent applies preliminary action by having the standby microcomputer generate drive signals in advance and preparing the switching circuit groups to receive both own and other drive signals before failure occurs. When a microcomputer fails, the switching circuit can immediately select the pre-prepared drive signal from the other microcomputer, avoiding sudden torque changes and ensuring continuous motor operation.
2Reliability
If two microcomputers are redundantly provided to improve reliability, then the system can continue operation when one fails, but control switching complexity and lag increase
Solution Approach 1:
The patent applies segmentation by dividing the control system into two independent systems, each with its own microcomputer, power converter, and switching circuit group. Each system can operate independently, and the switching circuit groups are segmented to handle only local switching decisions. This modular segmentation reduces overall control complexity while maintaining redundancy for reliable continuous operation.
3Stability of the object's composition
If switching circuit groups select between own and other drive signals, then torque continuity is improved, but the device structure becomes more complex
Solution Approach 1:
The patent introduces switching circuit groups as intermediary components between the microcomputers and power converters. These switching circuits act as mediators that selectively connect the output of either the own microcomputer or the other microcomputer to the power converter, ensuring smooth torque transition while isolating the complexity of the switching logic from the main control systems.
Data Source
AI summary
A motor control device is provided. In this motor control device, a first switching circuit group and a second switching circuit respectively provided between first and second microcomputers and first and second power converters receive drive signals generated by the microcomputers included in the own system and other drive signals generated by a microcomputer other than the microcomputers of the own system, select the own drive signal or the other drive signal according to selection signal from the microcomputers of the own system, and output the selected drive signal to the power converter of the own system. The first and second microcomputers output the selection signals to the switching circuit groups of the own system so as to select the own drive signal when the microcomputers are operating normally, and output the selection signal so as to select the other drive signal when a monitoring circuit of the system detects an faulty in the microcomputers.