Electric Machine Power Distribution for Drive Efficiency
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Solution Overview
Problem
Current electrified vehicle powertrains with multiple electric machines often operate inefficiently, leading to reduced efficiency, higher fuel consumption, and increased CO2 emissions due to separate operation of machines and underutilization of energy recovery and power support potential.
Innovation Solution
A method and drive system that combines the operation of at least two electric machines to minimize power losses by determining and distributing mechanical power based on loss characteristic curves and efficiency curves, optimizing torque and rotational speed to achieve maximum efficiency and reduce total power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple electric machines are operated separately in different operating ranges, then each machine can be controlled independently, but the overall efficiency of the drive system is reduced
Solution Approach 1:
The patent combines the control of multiple electric machines by distributing the total mechanical power requirement across all available machines based on their individual efficiency characteristics. Instead of operating machines independently, the control unit coordinates them to work together as an integrated system, assigning power distribution that maximizes overall efficiency while maintaining independent controllability when needed.
Solution Approach 2:
The system dynamically changes operating parameters (torque and rotational speed) of each electric machine based on real-time conditions and efficiency maps. By continuously adjusting these parameters and selecting optimal operating points from pre-stored efficiency data, the system achieves high overall efficiency while maintaining the flexibility to control each machine independently when required.
2Device complexity
If electric machines are operated separately without considering the entire machine set, then control complexity is reduced, but fuel consumption increases and CO2 emissions rise
Solution Approach 1:
The system performs preliminary actions by pre-storing efficiency maps and loss characteristic curves for each electric machine before operation. These pre-calculated efficiency data structures enable the control unit to quickly determine optimal power distribution without complex real-time calculations, reducing control complexity while achieving fuel-efficient operation through advance preparation of optimization data.
Solution Approach 2:
The control system implements feedback by continuously monitoring the actual operating conditions and comparing them with the stored efficiency maps. Based on this feedback, the control unit adjusts the power distribution among electric machines in real-time, ensuring optimal fuel consumption and CO2 emissions performance while maintaining manageable control complexity through iterative optimization.
3Device complexity
If the potential of electric machines for energy recovery and power support is not fully utilized, then system simplicity is maintained, but energy efficiency is reduced
Solution Approach 1:
The system dynamically adapts the operational roles of electric machines based on real-time vehicle conditions, continuously switching between different operating modes (energy recovery, power support, propulsion) to maximize energy efficiency. This dynamic approach allows the system to fully utilize the potential of electric machines for energy recovery and power support while maintaining operational simplicity through automated mode selection and transition management.
Data Source
AI summary
A method for operating a drive system of a motor vehicle which is equipped with at least two E-machines, the drive system, as well as to a motor vehicle provided with the drive system.