Hybrid Modulation for Three-level Boost Converter with ZVS near Double Gain

Three-level boost (TLB) converters operating under triangular current mode (TCM) have the merits of zero-voltage switching (ZVS) and low EMI. However, owing to the zero ripple near double gain, the ZVS of three-level boost (TLB) converters is lost, leading to the hard switching. In this article, the hybrid modulation with ZVS at valley current near double gain is proposed based on the modulation degree of freedom in TLB. The ZVS is achieved by only changing the penetration of the two-level switching states while keeping the constant switching frequency, which has the small current ripple and low turn-on loss. Implementation of the hybrid modulation considering the voltage balance is presented. The effectiveness of the proposed method is validated through experiments.