Motor Winding Disconnection Detection via Phase Shift
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Solution Overview
Problem
Existing motor abnormality detection systems fail to detect winding disconnections in a locked motor state, particularly when the actual current value is near zero, leading to delayed or undetected disconnections.
Innovation Solution
A motor abnormality detection apparatus that includes a locked state check, current value check, phase shift, and abnormality check components, which shifts the current command value's phase when the motor is locked and the current value is undetectable, allowing for disconnection detection by monitoring differences in current values post-phase shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor operates in a locked state with current value near zero, then the motor maintains position without descending, but the disconnection of winding cannot be detected
Solution Approach 1:
The invention changes the operating parameters by shifting the phase of the current command value when the motor is in locked state with current near zero. This phase shift moves the operating point out of the undetectable range, enabling disconnection detection while maintaining position holding capability through controlled current injection at different phases
2Stability of the object's composition
If the current value is near zero in locked state, then the motor remains stable, but the difference between current command value and actual current value becomes undetectable
Solution Approach 1:
The invention applies periodic phase-shifted current commands to the motor winding. By injecting current at multiple phase angles periodically, the system creates detectable current variations that enable disconnection detection while maintaining overall motor stability through controlled periodic excitation
3Duration of action of stationary object
If the motor is in locked state for extended period, then position is maintained, but disconnection detection is delayed even when disconnection occurs
Solution Approach 1:
The invention performs preliminary disconnection detection by shifting the current phase before the motor enters extended locked state or when first detected. This preliminary action ensures that disconnection can be detected immediately upon occurrence rather than delayed, while the motor maintains position holding capability during normal operation
Data Source
AI summary
A MGECU includes a locked state check part for checking whether a motor generator is in a locked state, a current value check part for checking whether a current command value or an actual current value as a current value is in a predetermined disconnection undetectable range including a current value of zero, a phase shift part for shifting a phase of the current command value so that the current command value is outside the disconnection undetectable range with a direction of rotation being unchanged in a case that the motor generator is determined to be in the locked state and the current value is determined to be in the disconnection undetectable range, and an abnormality check part for checking whether the motor generator has a disconnection in windings based on a result produced by controlling the motor generator with a phase-shifted current command value.