Electric Drive Motor Torque Control Under Thermal Limits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control methods for electric drive motors in vehicles unpredictably reduce power/torque supply, leading to sudden and unexpected drops, especially during high-performance driving, due to thermal and battery state limitations, which negatively impact driving experience and performance.
Innovation Solution
A control method that dynamically adjusts the maximum available power/torque level between a peak and a nominal value, allowing temporary overboost during driver requests for full power/torque, followed by a reduction to a lower level to manage thermal stress, independent of battery state and driving conditions, with predetermined timing to maintain performance and prevent component overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the maximum available power/torque level is reduced to manage thermal stress, then thermal stress on components is limited, but driving performance and acceleration capability deteriorate
Solution Approach 1:
The control system dynamically adjusts the maximum available power/torque level based on real-time thermal state monitoring. When thermal stress is detected, the system transitions from a static reduced power mode to a dynamic control mode that allows temporary overboost while actively managing thermal conditions through coordinated braking and power reduction, thereby maintaining both thermal safety and driving performance.
Solution Approach 2:
The system implements periodic monitoring of thermal stress conditions and applies cyclic power adjustments. During thermal stress events, the control algorithm alternates between reducing power to cool components and allowing temporary overboost when thermal conditions permit, creating a periodic action pattern that maintains both thermal safety and acceptable driving performance throughout the thermal event.
2Temperature
If the maximum available power/torque level is suddenly reduced due to thermal conditions, then component overheating is prevented, but driver experience and cognitive load deteriorate
Solution Approach 1:
The control system applies preliminary anti-action by proactively informing the driver before power reduction occurs. Through visual and/or acoustic warnings, the system prepares the driver for upcoming power limitations, allowing the driver to adjust expectations and driving behavior in advance. This prevents the sudden unexpected power drop that causes cognitive distraction, while still implementing necessary thermal management.
Solution Approach 2:
The system implements feedback by continuously monitoring thermal conditions and communicating status to the driver through the user interface. The feedback loop includes real-time information about thermal stress levels, upcoming power reductions, and current power availability, enabling the driver to understand system state and adjust driving accordingly, thereby maintaining good driver experience despite thermal constraints.
3Reliability
If the maximum available power/torque level is continuously reduced to prevent overheating, then component reliability is improved, but vehicle productivity and race performance deteriorate
Solution Approach 1:
The control system applies partial or excessive action by allowing temporary overboost conditions that exceed the normal maximum power/torque level. When thermal conditions permit, the system can deliver more than nominal power for short durations, particularly during critical racing moments such as exits from bends or overtaking attempts. This partial excessive action maintains component reliability over the long term while maximizing race performance when it matters most.
Solution Approach 2:
The system changes operating parameters dynamically based on thermal state and driving context. Rather than maintaining a continuously reduced power level, the control algorithm adjusts power/torque parameters in real-time, allowing higher power delivery when thermal conditions are favorable and reducing power when thermal stress is detected. This parameter changes approach maintains both component reliability and race performance by optimizing power delivery to match actual thermal capacity.
Data Source
AI summary
According to the control method, the power/torque that can be supplied by an electric drive motor in a vehicle is handled by setting and adjusting a maximum available level for the power/torque that can actually be supplied; the adjustment includes a reduction of the maximum available level from a peak value to a nominal value after the electric drive motor has supplied an actual power/torque equal to said peak value for a predetermined amount of time.