A novel control scheme of three-phase single-switch DCM boost PFC converter

Three-phase single-switch boost power factor correction (PFC) converter features zero-current turn-on for the switch, no reverse recovery in diode, constant frequency operation, simple control and low cost. That makes it suitable for low-to-medium power and cost-sensitive applications. Due to Discontinuous current mode (DCM), energy transfer does not cover the whole switching cycle, the rms and peak values of the inductor current is large which will increase the conduction and switching turn-off loss, resulting a lower efficiency of the converter. An optimum utilization control of switching cycles (OUCSC) is proposed in this paper so as to increase the critical boost inductance. A larger inductance is helpful for reducing the rms and peak current values of the main power components which will lower the conduction and switching turn-off loss, leading to a higher efficiency. The proposed method also achieves the output voltage ripple or the output storage capacitance reduction. And the harmonics comply with IEC 61000-3-2 Class A regulations.