Structure design and its parameter optimization of output filter in current balance compensation inverter for electrified railway

Output filter is analyzed of improvement and its parameter optimization in Current balance compensation inverter for electrified railway. The amplitude frequency response and phase frequency response of LC output filter is analyzed. The amplitude frequency responses of LC, RLC, M and LCL output filter are compared in this paper. The phenomena of the output filter can suppress the resonance and lower resistance active losses effectively when connecting a parallel circuit of small resistance and inductance to the capacity is pointed out too. Furthermore, the output filter´s influence to the current balance compensation inverter is discussed from the bidirectional power flow ability, transient current tracking, voltage total harmonic distortion, and harmonic current and resistance active losses. A fuzzy objective function, which is the weighted sum of the cost, power flow, the voltage total harmonic distortion, the harmonic current and resistance active losses, called as satisfaction level for practical engineering applications is proposed. The simulation results show that the output filter designed by optimization method can meet the performance requirements of the current balance compensation better than that designed just by experience.