Restricted Interleaving Phenomenon in Interleaved Boost PFC With Leg Sharing APF Circuit

Abstract

Active buffering increases the power density of on-board chargers for electric vehicles. An active power filter (APF) is used to provide a stiff DC voltage to charge the battery. This DC voltage is obtained from a single-phase AC grid using a front-end power factor correction circuit (PFC). To enhance the quality of grid current, interleaving is used. This paper integrates a half-bridge APF with an interleaved totem-pole PFC. Leg sharing between PFC and APF can further reduce the number of components. However, it increases component stress and reduces the degree of freedom of the circuit. As a result, the current flow deviates from its intended path. In shared structure, the line current mimics the PFC operation but fails to follow the exact PFC profile. This becomes prominent in the case of interleaving. This phenomenon is explored for the first time and termed as 'Restricted Interleaving Phenomenon'(RIP), which leads to increased input current ripple and affects the APF operation. This disturbance can be controlled by operating the circuit at a higher output voltage and increasing the APF switching frequency. Experimentally phenomenon is observed and analyzed in the proposed shared structure, followed by its control and impact on specific topologies. © 1972-2012 IEEE.