Electric Vehicle Powertrain Torque Distribution for Thermal Loss Minimization
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Solution Overview
Problem
The conflict between energy efficiency and cooling system operation in electric vehicle powertrains, where cooling is necessary for reliable component operation but consumes energy, reducing overall efficiency.
Innovation Solution
A method that estimates future power losses in the powertrain based on torque distribution and free rolling states of electric traction machines, minimizing energy waste and reducing cooling system operation by optimizing torque distribution and clutch states to reduce thermal losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cooling system is used to keep components within desired temperature range, then reliability and energy efficiency of components is improved, but energy consumption of the vehicle increases
Solution Approach 1:
The control system performs preliminary estimation of future power losses and proactively adjusts torque distribution before excessive heating occurs. By predicting thermal states and adjusting operation in advance, the system prevents overheating without requiring continuous high-capacity cooling, thus improving reliability while reducing energy consumption.
Solution Approach 2:
The system dynamically changes operating parameters (torque distribution, free rolling states) based on predicted thermal conditions. By adjusting these parameters proactively, the system maintains components within safe temperature ranges while optimizing energy efficiency, resolving the contradiction between reliability and energy consumption.
2Reliability
If torque is distributed between multiple electric traction machines, then powertrain reliability and thermal management are improved, but power loss increases due to multiple machine operation
Solution Approach 1:
The system dynamically adjusts torque distribution between electric traction machines based on real-time conditions and future predictions. Rather than static load sharing, the control system continuously optimizes which machines operate and at what torque levels, allowing the system to maintain reliability through redundancy while minimizing power losses by keeping machines in optimal operating ranges.
Solution Approach 2:
The control system changes operational parameters (torque allocation, machine engagement/disengagement) based on predicted power losses. By dynamically adjusting these parameters, the system can switch between different operational configurations to minimize energy loss while maintaining the reliability benefits of multiple traction machines.
3Loss of energy
If electric machines are kept in free rolling state to reduce power loss, then energy efficiency is improved, but control flexibility and response capability deteriorate
Solution Approach 1:
The system uses preliminary estimation of future driving conditions to proactively transition machines between free rolling and engaged states. By predicting upcoming torque demands, the system can prepare by engaging machines in advance, ensuring control flexibility is available when needed while maximizing free rolling operation during low-demand periods to minimize power loss.
Solution Approach 2:
The control system periodically assesses whether to maintain free rolling state or engage machines based on predicted future conditions. This periodic evaluation allows the system to alternate between energy-saving free rolling operation and controlled engagement, balancing power loss reduction with maintenance of control flexibility and response capability.
Data Source
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AI summary
The disclosure relates to a method for controlling a powertrain of an electric vehicle. The method comprises receiving a torque demand signal (S1). Thereafter, a future power loss within the powertrain is estimated as a function of a torque distribution between at least two electric traction machines of the powertrain (S2). Alternatively or additionally the loss can be estimated as a function of a free rolling state of at least one of the electric machines (S2). Subsequently, a torque distribution between the electric traction machines is determined and/or a free rolling state of at least one of the electric machines is determined which minimizes the future power loss (S3). Moreover, a corresponding data processing device, a corresponding computer program and a corresponding computer-readable medium are presented. Moreover, a powertrain for an electric vehicle is described. The powertrain comprises such a data processing device and at least two electric traction machines and/or a clutch device.