Traction Motor Torque Split Using Route-Ahead Thermal Prediction
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Solution Overview
Problem
Current vehicle energy management systems face challenges in efficiently controlling torque split between multiple electric traction machines, particularly in battery electric vehicles, due to conflicting attributes and constraints such as thermal management and stability, which can lead to inefficient energy use and potential overheating.
Innovation Solution
A controller that predicts operating temperatures and stability for each traction machine, adjusts torque requests, and generates control signals to dynamically manage torque split and activate cooling systems, using route-ahead information to anticipate thermal behavior and balance thermal loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If torque is increased to improve vehicle performance, then power output is improved, but thermal load on traction machines increases causing overheating
Solution Approach 1:
The controller predicts future operating temperatures of traction machines based on route information and torque demands. Before temperature thresholds are exceeded, the controller preemptively adjusts torque distribution or activates cooling systems, preventing overheating while maintaining performance during critical driving phases
Solution Approach 2:
The system dynamically changes operating parameters including torque distribution ratios between multiple traction machines, cooling system activation states, and torque reduction thresholds. These parameter adjustments are made in real-time based on predicted thermal behavior to balance performance and thermal management
2Temperature
If torque distribution is adjusted to balance thermal load, then temperature uniformity is improved, but vehicle stability may be affected
Solution Approach 1:
The controller dynamically adjusts torque distribution parameters between traction machines based on real-time temperature predictions and vehicle stability requirements. The system modifies torque split ratios to balance thermal loads while maintaining optimal vehicle dynamics through coordinated control of multiple actuators
3Temperature
If cooling systems are activated to reduce temperature, then thermal management is improved, but energy consumption increases
Solution Approach 1:
The controller activates cooling systems in advance based on predicted temperature trajectories before thermal thresholds are exceeded. By timing cooling activation strategically during predicted high-thermal-load periods, the system prevents overheating while minimizing unnecessary cooling operation and associated energy consumption
Solution Approach 2:
The system continuously monitors actual temperatures and compares them against predicted values, using this feedback to optimize cooling system operation. The controller adjusts cooling activation and intensity based on the difference between predicted and actual thermal states, energy availability, and driving conditions to minimize energy consumption while maintaining safe operating temperatures
Data Source
AI summary
The present disclosure relates to a controller for controlling operation of at least first and second traction machines in a vehicle. The controller includes a processor configured to predict an operating temperature of each of said at least first and second traction machines for at least a portion of a current route. The processor determines at least first and second torque requests for said at least first and second traction machines. The at least first and second torque requests are determined in dependence on the predicted operating temperatures of the at least first and second traction machines. The processor generates at least first and second traction motor control signals in dependence on the determined at least first and second torque requests. The present disclosure also relates to method of controlling at least first and second traction machines in a vehicle.