Three-phase power factor corrector based on capacitor-clamped topology

This paper presents a three-phase capacitor clamped converter to achieve power factor correction and harmonic elimination. There are two legs in the proposed converter to achieve three-level pulse-width modulation (PWM) and to control the line currents to be sinusoidal waves. Only eight power switches instead of twelve power switches used in the conventional three-phase flying capacitor converter were used in the proposed converter. Three control loops (DC link voltage control, neutral point voltage control and line current control) are used in the control scheme to achieve DC bus voltage regulation, to balance neutral point voltage and to draw the balanced and sinusoidal line currents. The mathematical model of the converter was derived and the control scheme was provided in the paper. The applications of the adopted circuit topology can be applied to AC motor drive and power quality compensation. Experiments were provided to verify the effectiveness of the proposed control scheme.