A novel active power filter with shunt transformer

In the paper, a novel active power filter with a shunt transformer and an inverter is proposed. A transformer is chosen and its primary winding is connected in parallel with harmonic source, the primary fundamental voltage is detected and functions as the given signal. A voltage-source inverter is applied to produce a controllable fundamental voltage source, which is energized across the secondary winding of the transformer. When the controlled voltage and the primary winding fundamental voltage satisfy a certain condition, the transformer exhibits a variable reactor to fundamental so as to compensate reactive power; whereas it exhibits primary leakage impedance of the transformer to harmonic so that the harmonic flow through the primary winding. The validity of the theory is proved by the simulation results.