Resolver Fault Monitoring with Torque Derating and Recovery
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Solution Overview
Problem
Resolver faults in electrically-powered torque machines, such as loss of signal, degradation of signal, and loss of tracking faults, lead to non-optimum performance and potential motor failure, making it difficult to diagnose and detect these faults effectively.
Innovation Solution
A hybrid powertrain system that monitors resolver signal outputs, derates motor torque capacity upon detecting a fault, and executes a torque ramp-up state when the fault clears, with notification of a fault only if the motor torque capacity fails to recover within a threshold time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional resolver fault detection schemes are used (monitoring duration and quantity of faults), then fault detection capability is provided, but false notifications occur and operational continuity is disrupted
Solution Approach 1:
The system dynamically adjusts torque capacity based on real-time resolver health status. When a fault warning state is detected, the torque capacity is derated to a lower level. When the fault clears, a torque ramp-up state is executed to gradually restore torque capacity. This dynamic adjustment allows the system to maintain operational continuity while responding to fault conditions, preventing false notifications from causing unnecessary shutdowns.
Solution Approach 2:
The system changes the torque capacity parameter in response to resolver fault conditions. By derating torque capacity during fault warning states and implementing a controlled ramp-up during recovery, the system transforms a binary fault-detection approach into a continuous parameter-adjustment approach. This allows the torque machine to operate through transient faults without triggering false notifications, thereby maintaining productivity while preserving reliable fault detection.
2Reliability
If torque capacity is immediately reduced upon fault detection, then safety is improved, but sudden shutdowns occur and performance is degraded
Solution Approach 1:
The system executes a torque ramp-up state as a preliminary action before fully restoring torque capacity after a fault clears. This gradual restoration process prepares the system for full operation by incrementally increasing torque capacity, allowing monitoring of system response during recovery. This preliminary action ensures safety by verifying system stability before full power restoration, while simultaneously ensuring smooth recovery without sudden jumps in torque that could cause operational issues.
3Difficulty of detecting and measuring
If fault notification is provided immediately upon detection, then diagnostic capability is improved, but false notifications increase and operator attention is wasted
Solution Approach 1:
The system uses feedback from the torque ramp-up state execution to determine whether to provide fault notification. Instead of notifying immediately upon fault detection, the system monitors whether the torque machine successfully executes the torque ramp-up and recovers to threshold torque capacity within a threshold recovery time period. This feedback mechanism allows the system to distinguish between transient faults (no notification) and persistent faults (notification provided), thereby improving diagnostic capability while reducing false notifications.
Data Source
AI summary
A method for monitoring an electrically-powered torque machine configured to generate torque in a hybrid powertrain system includes monitoring signal outputs of a resolver configured to monitor rotational position of the torque machine. Upon detecting a fault warning state associated with the signal outputs of the resolver, a motor torque capacity of the torque machine is derated. Upon a clearing of the fault warning state, a torque ramp-up state to increase the motor torque capacity of the torque machine is executed. Notice of an incidence of a fault associated with the signal outputs of the resolver is provided only when the motor torque capacity fails to achieve a threshold motor torque capacity within a threshold recovery time period while executing the torque ramp-up state.