Three-phase four-wire series hybrid active power filter with fundamental current bypass channel

A novel control scheme based on per-phase dq transformation for three-phase four-wire series hybrid active power filter with passive fundamental current bypass channel is proposed. The series active power filter presents a resistor to the grid harmonic current, by which, the load harmonic current will be obliged to flow into the passive power filters. At the same time, the voltage source inverter presents a resistor to the fundamental component of the inverter current and the grid fundamental current will be obliged to pass through the passive channel. So the inverter delivers the harmonic power only and the required rating of the active filter can be much smaller than that of conventional one. A 5 kW prototype is implemented digitally by TMS320F2407A(DSP). The experimental results validate the proposal control scheme.