Performance Analysis of Coupled Inductor Based Ripple Free Boost PFC AC-DC LED Driver

Abstract

Power factor correction (PFC) and the elimination of second harmonic ripple without using an electrolytic capacitor (EC) are the key factors for an AC-DC Light Emitting Diode (LED) driver. The ECs are used to diminish the pulsating current with double the supply frequency at the output which reduces the life span of the LED driver. In this paper, a Boost converter with a coupled Inductor Bi-directional converter (CIBDC) configuration is proposed. This configuration consists of a Boost PFC converter and CIBDC for replacing the short life span ECs with long life span film capacitors. Boost PFC is operated in discontinuous conduction mode (DCM) to obtain unity power factor and CIBDC diverts the ac component of the Boost PFC converter and allows the dc component to the LED load. Also, by using coupled inductor zero voltage switching (ZVS) is achieved for the power switches to reduce the switching losses. Hence, the proposed configuration has advantages of near unity power factor, reduced switching losses for improved efficiency, elimination of ECs, and low output current ripple. A 100 W AC-DC LED driver configuration is validated using PSIM software.