Abstract
It is a well known fact that, the instantaneous power of a single phase rectifier or inverter, always contains a double line frequency component. As a result, it is necessary to either add additional components to reduce the harmonic or increase the filter capacitor. In view of this dilemma, the motivation of this thesis is mainly focused to search for an effective double line frequency harmonic reduction control technique without adding additional components. Basically, the major contributions of this thesis can be summarized as follows. First, a novel single stage power factor corrector (PFC) topology is proposed. The new PFC contains only three active switches with a common terminal. This can not only simplify the gate driver but also provide more control flexibility. Then, an approximate double line frequency harmonic equivalent circuit is proposed for practical applications. To the author’s best knowledge, that double line frequency harmonic equivalent circuit has never been proposed in the world. Third, based on this model, a harmonic reduction technique is proposed to reduce the double line frequency harmonic without adding any component. Finally, a prototype PFC with 110V AC input, 48 V DC output and 200 W rating is constructed for verifying the effectiveness of the proposed control. Experimental results show that more than 97% of the output double line frequency harmonic can be reduced adding any extra component while the PF is kept above 0.98 and the efficiency remains above 90.7% from 40 W to 200 W loading. Keyword: Power factor corrector, double line frequency harmonic, Bridgeless