EV Drive Force Control via Torque Split to Avoid Noise Regions
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Solution Overview
Problem
Electric vehicles experience abnormal noises and vibrations during propulsion due to mechanical and electrical factors in the torque transmission path between the motor and the drive wheels, which are exacerbated by resonance.
Innovation Solution
A drive force control system that includes a controller with a vibration determiner to predict when the motor's operating point will enter a noise region and a torque ratio changer to adjust the torque ratio between the front and rear wheels, preventing the operating point from entering the noise region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor operates at high torque and speed to meet driving requirements, then the driving performance is improved, but the operating point enters the noise region causing abnormal noises and vibrations
Solution Approach 1:
The controller dynamically adjusts the torque ratio between front and rear wheels by changing operational parameters (torque distribution ratio) to shift the motor's operating point away from the noise region while maintaining the required total driving torque. This resolves the contradiction by modifying control parameters rather than hardware configuration.
Solution Approach 2:
The system implements dynamic torque ratio adjustment based on real-time operating conditions. The controller continuously monitors the motor's operating point and adaptively changes the torque distribution ratio to keep the operating point outside the noise region, transforming a static torque ratio into a dynamic control variable.
2Object-affected harmful factors
If the torque ratio is adjusted to avoid the noise region, then noises and vibrations are reduced, but the torque distribution between front and rear wheels deviates from the reference ratio
Solution Approach 1:
The torque ratio is transformed from a fixed reference value into a dynamic control variable that adjusts in real-time. The controller monitors the motor's operating point and adaptively modifies the torque ratio to maintain the operating point outside the noise region, ensuring dynamic stability rather than static rigidity.
Solution Approach 2:
The controller implements a feedback mechanism by continuously monitoring the motor's operating point (torque and speed) and comparing it against the noise region boundaries. Based on this feedback, the controller adjusts the torque ratio to keep the operating point in the acceptable range, creating a closed-loop control system that balances noise reduction with driving performance.
Data Source
AI summary
A drive force control system for an electric vehicle configured to reduce noises and vibrations during propulsion by controlling a motor serving as a prime mover. A controller of the drive force control system comprises: a vibration determiner that determines whether an operating point of the motor will enter a noise region; and a torque ratio changer that changes a ratio between a torque driving a first wheel and a torque driving a second wheel to deviate the operating point of the motor from the noise region, when the vibration determiner determines that the operating point of the motor will enter the noise region.