动车组(EMU)牵引供电系统采用25 kV单相牵引变压器从接触网取电，EMU运行过程中的弓网离线、功率器件的非线性特性、硬件电路和控制系统的不对称性等，均会引起直流分量通过电气回路注入车载牵引变压器，引起变压器的直流偏磁。通过将比例-积分-谐振(PIR)控制应用于电流内环控制器，同时实现正弦信号的稳定跟踪和直流分量的抑制。仿真和硬件在环的半实物仿真结果验证了该控制策略的有效性。

The traction power supply system of electric multiple unit (EMU) adopts 25 kV single-phase transformer to draw power from the traction catenary. The disconnection of pantograph-catenary during the locomotive running operation, nonlinear characteristics of power devices, and the asymmetry of hardware circuit and control system can all cause the DC components to inject into the vehicle traction transformer through the electrical circuit, and result in the DC magnetic bias of transformer. By applying the proportional-integral-resonance (PIR) control to the current inner loop controller, the stable track of the sinusoidal signal and the suppression of the DC components are realized. The simulation and the hardware-in-the-loop simulation results show the effectiveness of the control strategy.