Study on Power Ratio Between the Front Motor and Rear Motor of Distributed Drive Electric Vehicle Based on Energy Efficiency Optimization 2016-01-1154

For distributed drive electric vehicles (DDEVs), the influence of the power ratio between the front and rear motors on the energy efficiency characteristics is investigated. The power-train systems of the DDEVs in this study are divided into two different power-train configurations. The first is with its front axle driven by wheel-side motors and the rear axle driven by in-wheel motors, and the second is with both the front and rear axles driven by in-wheel motors. The energy consumption simulation and analysis platform of the DDEV is built with Matlab/Simulink. The parameters of the key components are determined by the experiments to ensure the validity of the data used in simulation. At the same time, the vehicle’s average energy efficiency coefficient is defined to describe the energy efficiency characteristics of the power-train strictly. Besides, the control strategies for driving and braking of the DDEV based on energy efficiency optimization are presented. Then, based on the existing energy efficiency MAPs of the power components including motor, inverter and reducer, the methods which calculate the energy efficiency MAPs of the power components with other sizes by calculating power losses related to the parameters and sizes are proposed. Thus, the energy efficiency MAPs of the power-train with different power ratios between the front and rear motors are acquired. Several simulations with different typical driving cycles are implemented to compare the energy efficiency characteristics of different power-train configurations. As a result, based on the energy efficiency optimization, we propose the best power ratio between the front and rear motors, which is about 1:2.5 for the power-train using front wheel-side motors and rear in-wheel motors, while about 2:1 for another configuration. Our works can provide recommendations for allocation of front motor power and rear motor power for DDEVs.