Motor Rotation Angle Control with Dual-Sensor Fault Startup
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Solution Overview
Problem
Existing vehicle control devices cannot accurately identify which of the dual-system magnetic detection elements is abnormal, leading to potential failure of motor operation even when one of the systems is functioning correctly.
Innovation Solution
The vehicle control device incorporates dual-system control circuits and rotation detection circuits that calculate an absolute rotation angle of the motor, storing this angle when the power is off and comparing it with the recalculated angle upon power-on to determine normal operation, allowing appropriate motor control even if one system is abnormal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual-system magnetic detection elements are used to detect motor rotation angle, then reliability of motor control is improved, but ability to identify which specific detection element is abnormal deteriorates
Solution Approach 1:
The system performs preliminary action by storing the absolute rotation angle value in advance when the power source is turned off. This stored value is then used for comparison when the power source is turned on, enabling the system to identify abnormal detection elements before critical failures occur.
Solution Approach 2:
The system implements feedback by comparing the stored absolute rotation angle with the newly calculated absolute rotation angle upon power-on. This feedback mechanism enables the control circuit to detect discrepancies and identify which specific magnetic detection element has become abnormal, resolving the inability to pinpoint failures in dual-system configurations.
2Reliability
If the system requires confirmation that both dual-system rotation detection circuits are normal before starting, then safety is improved, but ease of operation deteriorates when one system is already abnormal
Solution Approach 1:
The system applies dynamics by adaptively changing its operational state based on detection results. When one rotation detection circuit is identified as abnormal, the system dynamically switches to operate using only the normal circuit, rather than maintaining a rigid requirement for both circuits to be normal. This enables the motor to start and operate safely even when one system fails.
3Difficulty of detecting and measuring
If the control system performs comparison of absolute rotation angles to identify abnormalities, then diagnostic capability is improved, but device complexity increases
Solution Approach 1:
The system implements self-service by using its own existing absolute rotation angle calculation capability to perform self-diagnosis. The control circuit compares previously stored angle data with newly calculated data, enabling the system to detect and identify abnormal detection elements using its inherent computational resources without requiring additional external diagnostic equipment.
Data Source
AI summary
A vehicle control device includes: dual-system control circuits that control power supply to dual-system winding sets of a motor; and dual-system rotation detection circuits. The control circuits calculate an absolute rotation angle of the motor, and, when a power source is turned off, store an absolute rotation angle of the motor at that time. The control circuits start when the power source is turned on and the absolute value of a difference between an absolute rotation angle that was stored when the power source was turned off last time and an absolute rotation angle that is calculated when the power source is turned on this time is equal to or smaller than a given threshold value, regardless of whether an abnormality has occurred in one of the dual-system rotation detection circuits or an abnormality of the dual-system rotation detection circuits is not determinable.