An Integrated EV Battery Charger With Three-Level Boost PFC Converter and H5-Bridge Based Bidirectional DO-CLL Series Resonant Converter for Wide Battery Voltage Range

This article proposes an efficient two-stage ac–dc converter for off-board electric vehicle charging applications over a wide range of battery voltages. The proposed charger integrates a three-phase three-level boost power factor correction (TL-BPFC) converter with a bidirectional dual-output CLL (DO-CLL) series resonant converter. In the ac–dc conversion stage, three switches are controlled using a hysteresis technique to enhance input power quality. The second stage, responsible for dc–dc conversion, incorporates an H5-bridge on the primary side and a voltage doubler circuit on the secondary side, providing decoupled outputs through two high-frequency transformers (HFTs) connected to resonant tanks. This configuration allows flexible adjustment of the resonant tank inputs, which can operate in full-bridge (FB), half-bridge (HB), or inactive (IA) modes. This design provides a key advantage of a wide voltage range during forward and reverse operation using reconfigurable H5 bridge. Additionally, the switches in the DO-CLL achieve zero-voltage switching (ZVS) during turn-on, and the identical HFTs minimize the cross-coupling effect, to enhance the efficiency. A scaled-down laboratory prototype of the off-board EV charger is developed to provide two distinct outputs of 400 V and 200 V, achieving an overall efficiency of 97.6%.