Bidirectional T-Type Resonant Converter With Four-Level-Waveform-Based FHSM

Aiming at the zero-voltage switching (ZVS) realization problem of the existing fundamental harmonic synchronized modulation (FHSM)-controlled bidirectional resonant converters with center-aligned resonant network port voltages under wide-voltage operation, this paper proposes a bidirectional resonant converter with T-type bridge structure and four-level-waveform-based FHSM (4L-FHSM). By constructing a four-level resonant network port voltage, the phase relationship between switching instants and fundamental component is modified, enabling full-range soft switching with reduced magnetizing current. In addition, fixed-frequency voltage regulation and symmetric bidirectional voltage gain decoupled from load and resonant parameters can be realized in the proposed converter. A 1-kW experimental prototype is built to verify the feasibility of the proposed approach.