Electric Drive Fault Isolation Using Torque Discrepancy
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Solution Overview
Problem
Electric vehicles lack effective fault detection and isolation systems for their drive systems, leading to potential loss of propulsion and increased risk of 'walk home' situations due to undetected component failures.
Innovation Solution
An integrated fault isolation and prognosis system that utilizes sensors to detect and isolate faults in electric drive systems without additional sensors, predicting failures and implementing mitigation strategies to prevent loss of propulsion and ensure vehicle reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fault detection systems are added to electric drive systems, then reliability is improved, but device complexity increases
Solution Approach 1:
The existing sensors in the electric drive system are made to serve dual purposes: their original functions plus fault detection. The controller processes sensor data to generate health indicators and detect faults without requiring dedicated fault detection hardware, making the system self-diagnostic
Solution Approach 2:
Existing sensors are utilized for multiple functions - both their primary measurement tasks and fault detection. The controller performs multiple roles including motor control, data processing, and fault diagnosis, reducing the need for separate dedicated systems
2Measurement precision
If additional sensors are added for fault detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The existing sensors monitor their own operational status and the system's health by analyzing their measurement data. The controller extracts fault information from normal operational sensor readings without requiring separate diagnostic sensors
Solution Approach 2:
Virtual sensors or health indicators are created through software processing of existing sensor data. The system generates derived measurements that indicate fault conditions without physical additional sensors
Data Source
AI summary
An electric drive system of a vehicle comprises a motor, a position sensor, an inverter, sensors to sense current and voltage supplied to the motor, and a controller to control the motor by controlling the inverter based on data from the position sensor and the sensors and a torque command. The controller estimates a motor torque using a motor model, calculates the motor torque, and generates a first state of health for the electric drive system based on a difference between the estimated and calculated motor torques. The controller generates, in response to the first state of health being less than or equal to a first threshold, a second state of health for at least one of the position sensor, the sensors, and the motor, and determines whether one of the position sensor, the sensors, and the motor is faulty based on the first and second states of health.