An Inductive Filtering-Based Traction Transformer for High-Order Harmonic Suppression of HSR

There is ever-increasing high-order harmonic pollution caused by high-speed locomotives with PWM rectifier in nowadays railway traction power supply system (TPSS). These high-order harmonic components injected from the electric train will aggravate transformer vibration, noise, and loss and interfere with other locomotives powered by the same power-supply station. Harmonic resonance will occur when the harmonic frequency matches the inherent resonance frequency of TPSS. An inductive filtering-based traction transformer is designed for the restricted installation space in this paper, aiming to eliminate high-order harmonic. A filtering winding is added in the traction transformer, which exhibits superconducting characteristics for high-order harmonics, thereby suppressing high-order harmonics without affecting the transmission of electric energy at power frequency. The winding arrangement of the abovementioned transformer is introduced. The compound short-circuits impedance of the traction transformer is calculated using the field-circuit coupling method. Phase shift modulation is employed to increasing equivalent switching frequency. A simulation model was built in the Simulink environment to verify the feasibility of the method, and the results show that the proposed method can effectively suppress high-frequency harmonics.