Soft-Switching Dual-Active-Bridge-Based Converter With High Efficiency and Low Radiated EMI for Double-Sided LCC WPT Systems

In conventional WPT systems, soft switching is achieved by utilizing the reactive current generated by the resonant network. However, this reactive current circulates throughout the entire circuit, increasing conduction loss and thereby reducing the overall system efficiency. To address this issue, a soft-switching dual-active-bridge-based converter with an LC circuit connected to a single leg has been proposed. The proposed converter generates the required reactive current for soft switching using the LC circuit instead of the resonant network, which significantly reduces conduction loss. The fundamental performance of the proposed converter has been demonstrated using the traditional series/series (S/S) topology. This paper applies the proposed converter to a double-sided LCC topology, which has different circuit characteristics from the S/S topology, and demonstrates its effectiveness. Experimental results show that, at a transmission power of 3.3 kW, the proposed system reduces radiated EMI by an average of 4.3 dB$\mu$V and improves efficiency by 2.0 percentage points compared to the conventional system operating with hard switching. Furthermore, it achieves a 3.9 percentage point improvement in efficiency compared to the conventional system operating with soft switching.