Optimization of Transformer Design Parameters of a 20kW SiC-Based Dual-Active Bridge Converter for Enhanced Efficiency

This paper proposes a comprehensive optimization method to determine the optimal design parameters of a high-frequency (HF) transformer in a dual-active bridge (DAB) converter. To achieve high efficiency under heavy load conditions, it is essential to minimize the conduction loss of the DAB. Not only the modulation scheme but also the turns ratio and leakage inductance of the HF transformer are critical parameters that influence the operation and efficiency of the DAB. To address this issue, this paper presents a design method based on nonlinear optimization to derive the optimal combination of HF transformer and modulation parameters that minimizes conduction loss. By adopting a zero-voltage switching (ZVS)-enhanced triple-phase-shift (TPS) modulation scheme, both conduction loss and switching loss are minimized, while the optimal modulation parameters are determined simultaneously. Experimental demonstration of the optimized parameters is performed using a SiC-based 20 kW DAB converter hardware.