A Multiplexed Bridge Arm Combined ZCS Full-Bridge Converter Without High Voltage Filter Inductor for MVDC Grid

This paper proposes a multi-path bridge arm combined zero voltage switch (ZCS) full bridge converter that does not require a high voltage filter inductor. Its main feature is the realization of energy transfer using only the leakage inductance of the transformer or by adding a small low-voltage inductor, along with capacitive filtering suitable for medium and high voltage applications. The converter achieves zero current turn-on and turn-off of four main power devices, as well as zero voltage and zero current turn-on and zero voltage turn-off of two auxiliary power devices by introducing an auxiliary transformer, which allows the current of the main transformer to reduce to zero during the freewheeling phase. This is crucial for multifunctional DC transmission (MVDC) applications. This paper discusses the working principle in detail, resolves the design issues of transformer tap ratio and low-voltage inductor, and provides simulation verification.