Train Impedance Reshaping Method for Suppressing Harmonic Resonance Caused by Various Harmonic Sources in Trains-Network Systems With Auxiliary Converter of Electrical Locomotive

With the development of electrified railway, harmonic resonance accidents occur from time to time. Based on the mechanism of resonance, a harmonic resonance suppression radical method by impedance reshaping is proposed. Thus, the equivalent impedance of the train position is significantly reduced. Compared with the traditional method of improving harmonic current, this method of impedance reshaping can not only suppress the resonance caused by its own harmonic, but also suppress the resonance caused by other trains or other unknown harmonic sources. Harmonic impedance of the train in the resonant frequency is reshaped by detecting the resonance voltage and controlling the auxiliary converter harmonic current. The resonance identification and parameter settings of the impedance reshaping control are also discussed. The proposed harmonic resonance suppression strategy is fully tested with an auxiliary converter control in a simulation trains-network system model. The performance of the proposed strategy is further evaluated on the experimental platform. Both the results verify the effectiveness and feasibility of the proposed strategy. The application of SiC devices makes it effective to suppress the resonance of thousands of hertz. The experiment was validated in two cases. One is the resonance caused by the harmonic current of the train itself. The second is the resonance caused by the harmonic current of trains in other locations. In both cases, the train using impedance reshaping method can ensure that the resonance of its position is effectively suppressed.