四轮毂电机驱动电动汽车动力系统优化匹配

Optimal Matching of Powertrain System of Four In-wheel-motor Actuated Electric Vehicle

为了研究四轮毂电机驱动电动汽车电机功率在各轴之间的匹配与回收能量多少之间的关系,采用理论分析和仿真相结合的方法,对不同匹配方案下的能量回收效果进行了对比分析。基于相关标准要求,确定了整车和动力性参数,计算整车额定功率、峰值需求功率和轮毂电机额定转速、峰值转速等,并建立了整车需求功率的二次再分模型。该模型对整车需求功率先在前/后轴之间按一定比例分配,再将各轴需求功率在左右车轮间平均分配。通过对整车制动动力学的分析,对前/后轴制动力按照理想制动力分配策略的情况,提出了电机功率在各轴之间匹配的推荐方案。基于Matlab/Simulink和CarSim软件搭建四轮毂电机驱动电动汽车联合仿真模型,采用分层取样得到多个前/后轴轮毂电机功率分配方案,研究在理想制动力分配策略下,制动强度分别为0.1,0.2和0.3,以及新欧洲运行循环(NEDC)、中国城市乘用车工况(CCDC)和纽约城市运行循环(NYCC)3种典型循环工况下不同分配方案时制动回收能量的差异,得到前/后轴轮毂电机功率最优匹配,并对最优方案动力性进行了验证。理论和仿真结果表明:当前/后轴轮毂电机功率分配比与前/后轴静态垂直载荷比相近时,电动汽车将获得最好的能量回收效果。

In order to study the relationship between the matching of motor power in different axles and the amount of energy recovery for four in-wheel-motor actuated electric vehicles, the energy recovery effects of different matching schemes are compared and analyzed by combining theoretical analysis with simulation. According to the requirements in the relative standards, the power performance parameters are determined. The required rated/peak powers of the vehicle, the rated/peak speed of the motor are calculated, and the redistribution model of the power that the vehicle required is built. According the model, the required power of the vehicle is distributed in a certain proportion between the front and the rear axles, and the required power of each axle is distributed equally between the left and right wheels. By analyzing the braking dynamics of the vehicle, a recommended scheme of powertrain matching to the front and the rear axles is put forward according to ideal braking force distribution strategy for the front and rear axles. The co-simulation model of the subject electric vehicle based on MATLAB/Simulink and CarSim is built. The optimal matching schemes of hub motor on the front and rear axles are obtained by stratified sampling. The differences of brake recovery energy in different distribution schemes under the conditions of braking strengths of 0.1, 0.2 and 0.3, typical driving cycles of New European Driving Cycle(NEDC), China City Driving Cycle(CCDC) and New York City Cycle(NYCC) using ideal braking force distribution strategy are studied respectively. The optimal matching of front/rear axle hub motors is obtained, which verified the power performance of the optimal scheme. The theory and simulation results show that when the power distribution ratio of the in-wheel-motors on the front and rear axles equals to the static vertical load on the front and rear axles, the braking energy recovery is superior to other matching scheme.