Configuration of a Novel Hybrid Active Power Filter and its Control Method

In order to meet the requirements of harmonic elimination and reactive power compensation in substation, a novel configuration of hybrid active power filter was proposed in this paper. Passive filter of this system can be used for reactive power compensation as well as for harmonic mitigation caused by nonlinear load. A small-rated active power filter, which is shunted to fundamental resonance circuit, is connected in series with a matching transformer, thus the injection type of hybrid active power filter is formed. Basic principle of this configuration is introduced particularly. Then the steady compensation characteristic and the resonance-damping characteristic of this system are analyzed in detail. Based on the analysis of bode diagram, a frequency dividing control method is proposed, which consists of generalized integrator control unit and fuzzy adjuster unit. Generalized integrator is used for frequency dividing integral control while fuzzy arithmetic is for adjusting PI coefficients timely. Compared with other control methods, the shorter response time and higher control precision are the advantages of the proposed one. Simulation and operation results with this new filter installed in a copper plant prove the feasibility and validity of the novel configuration and the control scheme.