A Front-Driven Independent Power Factor Partial Compensation for Decreasing Capacity in Electrified Railway

The railway power conditioner using partial compensation (PC) mode can compensate well for reactive power and negative sequence current with lower output current in electrified railway. In prior research, the independent power factor partial compensation mode (IPFPCM) had a significant impact on compensation current (CC) capacity reduction. However, the conservative voltage unbalance rate (VUR) rear-driven (RD) condition restricts the feasible region of IPFPCM, thereby hindering the further decrease of CC. This article proposes a VUR front-driven partial compensation (FD-PC) strategy based on IPFPCM. By reasonably combining VUR with other constraints, a larger feasible region is retained in the FD-PC solution procedure, further reducing CC. Since the mathematical model of FD-PC with three freedom degrees does not have an analytical solution, the fireworks algorithm is employed to determine efficiently the optimal solution. Through comparison, it has been proven that the proposed strategy can reduce the CC capacity by up to 17.63% compared to RD-PC under specific operating conditions. Simulation and experimental results show the effectiveness of the proposed strategy.