Counter-electromotive force of DC motor is simulated accurately with the model. Conduction angle a is calculated by use of the relationship between the function of locomotive tractive characteristic and rectifier circuit. So AC side datum of electric locomotive are gained. 仿真模型中比较准确的模拟了直流电机的反电势,利用机车牵引特性函数与整流回路的关系对导通角α进行了计算,得到电力机车交流侧的数据。