Dual-Motor EV Torque Balancing Under Battery Power Limits
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Solution Overview
Problem
In electric vehicles with multiple independent electric motors, insufficient battery power allocation can lead to unmet torque requests, causing unintended yaw moments and reduced vehicle drivability.
Innovation Solution
A method is employed to balance the unmet torque across motors by reducing permitted torque at one or both motors, ensuring compliance with battery power allocation, thereby maintaining intended yaw moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the requested torque at electric motors is adjusted to comply with battery power allocation, then power compliance is improved, but unintended yaw moment is introduced reducing vehicle drivability
Solution Approach 1:
The system dynamically adjusts motor torque parameters by calculating unmet torque (difference between requested and permitted torque) and redistributing it through balancing operations. This involves changing torque magnitude and distribution parameters while maintaining power compliance, thereby resolving the contradiction between power constraints and drivability through quantitative parameter optimization
2Stability of the object's composition
If torque is reduced at one or both motors to balance unmet torque, then yaw moment stability is improved, but motor power utilization is reduced
Solution Approach 1:
The system applies partial torque reduction rather than complete elimination of unmet torque. By balancing unmet torque proportionally across motors and applying it as a reduction to permitted torque, the system achieves yaw moment stability while retaining partial power utilization, avoiding excessive torque cuts that would unnecessarily reduce motor power utilization
Data Source
AI summary
Methods and systems for a vehicle are provided. A method for a vehicle includes coupling two motors to an axle. Furthermore, the method includes, at each of the two motors, setting a requested motor torque to a permitted motor torque in compliance with a threshold motor power, determining an unmet motor torque as a difference between the requested and the permitted motor torque, and balancing the unmet motor torque, including reducing the permitted motor torque at one or both of the two motors.