Average Current Control of a Series-Type Single-Phase PFC With Hybrid Modulation

This letter proposes a hybrid modulation scheme for the average current control (ACC) of the series-type single-phase power factor correction (PFC). The series PFC is a newly developed harmonic correction method for single-phase diode rectifier. It is composed of a hybrid full-bridge inverter and is in cascade between the dc terminal of the diode rectifier and the dc load. When the conventional ACC is applied, due to the large duty-ratio variation at the low-frequency transition points, the line current waveforms exhibit large distortion at the low-frequency switching points. A hybrid scheme, which combines the leading-edge and the trailing-edge modulation, is developed to overcome this problem. The reference signal selection and control logic design are discussed and implemented. Experimental results show that the proposed hybrid approach is able to reduce the harmonic distortion in the line current significantly, as compared with the conventional ACC control.