Motor Drive Controller for Electric Vehicle Wheel Slip
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Solution Overview
Problem
In electric traction vehicles, significant time delays in processing and transmitting wheel speed feedback signals can lead to instability due to the need for the vehicle controller to adjust torque references, causing wheel slip and wheel locking issues.
Innovation Solution
A motor drive controller is used to determine a second torque value based on a reference speed and wheel speed, allowing it to select either the torque reference from the vehicle controller or a second torque reference to limit wheel speed, thereby reducing the processing burden on the vehicle controller and stabilizing the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle controller processes wheel speed feedback signals and adjusts torque reference values, then wheel slip and wheel locking can be prevented, but significant time delays occur causing vehicle instability
Solution Approach 1:
The control system is segmented into two levels: the vehicle controller handles high-level torque reference generation, while the motor drive controller handles real-time wheel speed feedback processing and torque adjustment. This segmentation allows the time-critical wheel slip prevention function to be executed at the motor drive controller level, reducing communication delays while maintaining overall system reliability
Solution Approach 2:
The motor drive controller acts as an intermediary between the vehicle controller and the motor. It receives torque reference values from the vehicle controller and wheel speed feedback signals, processes them locally to determine actual torque output, and sends commands to the motor. This intermediary role enables real-time control without requiring constant communication with the vehicle controller, reducing time delays
2Reliability
If the vehicle controller adjusts torque reference values based on wheel speed feedback, then wheel slip and wheel locking are reduced, but the processing burden on the vehicle controller increases
Solution Approach 1:
The control processing functions are segmented between the vehicle controller and motor drive controller. The vehicle controller focuses on generating torque reference values based on vehicle-level parameters, while the motor drive controller handles wheel-level feedback processing and torque adjustment. This segmentation reduces the processing burden on the vehicle controller while maintaining wheel slip prevention capability
Solution Approach 2:
The motor drive controller performs self-service by independently processing wheel speed feedback signals and adjusting torque output without requiring constant intervention from the vehicle controller. It autonomously determines the actual torque applied to each wheel based on local sensor data and control algorithms, reducing the overall system complexity
Data Source
AI summary
A method of reducing wheel slip and wheel locking in an electric traction vehicle includes receiving in a first controller a first signal value representative of a first amount of torque to be applied to at least one wheel of the electric traction vehicle by a motor coupled to the wheel and to the first controller, and a second signal value representative of a reference speed of the electric traction vehicle. The first and second signal values are generated by a second controller in communication with the first controller. The method also includes receiving in the first controller a third signal value representative of a speed of the at least one wheel, determining in the first controller a torque output signal using the first, second, and third signal values; and transmitting the torque output signal from the first controller to the motor.