Study On The Regenerative Braking Strategy For The Motor Driving System Of Electric Vehicles

With the development of energy storage and motor driving technology, pure electricvehicles, one of the cleanest vehicles, will gradually become the most efficient ones. Thebraking energy recovery technology which is specially utilized to improve the energyefficiency in electric vehicles has broad prospects. But the efficiency of energy recoverysystem is mainly affected by the following three aspects:(1) The braking force distributionmethod for determining the total input energy;(2) The control method of Motor DC/DCdriving system for improving the efficiency of energy recovery;(3) The control method ofcomposite power source for guarantying the energy storage. To address the above issues, thispaper respectively designed optimized the strategy.In the terms of the braking force distribution method, combined with the ideal brakingforce distribution curve and strategies commonly used in regenerative braking forcedistribution, the control method of optimized best braking force distribution is designed; Inorder to optimize the control method of Motor DC/DC driving system, the closed-loop controlmethod based on the average current feedback is designed. The soft-switching technology isused to improve the efficiency of the power converter. The electric demands forsoft-switching are analyzed. For the control method of composite power source, combinedwith the commonly used battery-ultra capacitor control strategy, the control strategy based onthe logic threshold method is designed to ensure the storage of energy.After the achievement of the control strategy designation, the computer simulation toolsare used to verify it. The simulation system is secondary developed on the ADVISORplatform. It is applicable to the pure electric mini-bus with dual-energy source. The strategy issimulated in three urban operating conditions. The result which was analyzed from theworking currents of source units and the energy usage shows that the designed controlstrategy can boost the efficiency of energy recovery system, and the economic performanceand power performance are refined simultaneously.