A hybrid active power compensation device for current balance of electrical railway system

A hybrid active power compensation device for current balance applied to electrical railway system is proposed. The device consists of inductive filter transformer, reversible single-phase PWM rectifier through a capacitor formed symmetrical structure are installed in two feeders of an impedance-matching balance transformer or a Scott wiring transformer. Inductive filter transformer can compensate reactive power and harmonic currents, rectifier achieve only active current are outputted by two feeders. The principle of the inductive filter transformer is described in detail. It can eliminate voltage harmonic effectively, ensure the stability of DC bus voltage. Neural network PSO-BP algorithm to detect active current is presented to improve precision of active current. The simulation and experimental results both prove the device can effectively suppress harmonics, compensate reactive power, and balance two feeder´s loads, together. So it can eliminate the negative sequence current of the primary side.