THE C TYPE HYBRID ACTIVE POWER FILTER

The paper presented a novel hybrid active power filter structure, which is the combination of a normal C type filter and active power filter(APF) of the voltage source type. In this circuittopology, the APF does not need to endure fundamental voltage and current, and only bear part of harmonic current. The ratio of the APF output transformer can be less than 1, so the D.C. voltage level of the APF is low with respect to the grid voltage. With the composite control strategy given in the paper, the hybrid APF can compensate some appointed load harmonic accurately and compensate other harmonic partially. The presented C type hybrid APF are characterized by small APF capacity, simple control, well filtering effect and easy realization. It is suitable for harmonic compensation in high voltage and large current condition. Theoretical analysis is verified by simulation and experiment results.