Optimization of gear ratio and power distribution for a multimotor powertrain of an electric vehicle

ABSTRACT

The architecture and design of the propulsion system of electric vehicles are highly important for the reduction of energy losses. This work presents a powertrain composed of four electric motors in which each motor is connected with a different gear ratio to the differential of the rear axle. A strategy to reduce energy losses is proposed, in which two phases are applied. Phase 1 uses a divide-and-conquer approach to increase the overall output efficiency by obtaining the optimal torque distribution for the electric motors. Phase 2 applies a genetic algorithm to find the optimal value of the gear ratios, in which each individual of each generation applies Phase 1. The results show an optimized efficiency map for the output torque and speed of the powertrain. The increase in efficiency and the reduction of energy losses are validated by the use of numerical experiments in various driving cycles.

KEYWORDS:

• Powertrain
• electric vehicle
• genetic algorithm
• divide-and-conquer
• multimotor

Acknowledgements

This work was supported by the research group Consorcio Automotriz at Tecnologico de Monterrey. The first author would like to acknowledge the support provided by CONACYT (the Mexican National Council for Science and Technology) and the hospitality of the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology.

Disclosure statement

No potential conflict of interest was reported by the authors.