Energy saving control based on motor efficiency map for electric vehicleswith four-wheel independently driven in-wheel motors

For four-wheel independently driven in-wheel motor electric vehicles, the four-wheel drive/braking torque can be controlled independently. Therefore, it has an advantage that energy saving control can be applied effectively. This article studies several energy saving control methods from two levels of driving and braking for four-wheel independently driven in-wheel motor electric vehicles under urban conditions based on the motor efficiency map. First, the energy saving control logic and the evaluation index were proposed in the article. The four-wheel drive torque was online optimized in real time through drive energy saving control, in order to improve the driving efficiency in the driving process of electric vehicles. According to the theory of ideal braking force distribution and Economic Commission of Europe braking regulations, the parallel regenerative braking control method based on the motor efficiency map was then studied. The parallel regenerative braking control method was applied to four-wheel independently driven in-wheel motor electric vehicles. The simulation analysis under typical urban driving cycle conditions was carried out to determine the braking intensity of the parallel brake front axle separate regenerative braking, and finally the braking energy recovery rate of electric vehicle can be improved in the low speed and low braking torque. Finally, simulation experiments have been carried out to verify the researched method under the NEDC, UDDS, and J1015 urban driving cycles. The simulation results show that the energy saving control methods have an obvious effect on energy saving under the urban driving cycle conditions.