Onboard DC Solid State Transformer Based on Series Resonant Dual Active Bridge Converter

摘要

Medium voltage DC (MVDC) grid has several key advantages over MVAC grid and becomes a promising solution to onboard Integrated Power System (IPS). This paper proposes a DC solid state transformer to work as the interface between MVDC grid and low voltage equipment. The topology composes of input-series-output-paralleled series resonant dual active bridge (SRDAB) converter. Traditional method utilizes first harmonic approximation to analyze power and soft switching characteristics of SRDAB, but the results are not accurate. In this paper, steady-state modeling of SRDAB considers all the harmonic components. Then the system control algorithm is proposed to realize DC bus equalization and meet power flow command. Simulation and experiment results are presented to verify the analysis.