DAB-based PET in MVDC traction and shipboard applications with distribution and redundant control

Medium-voltage DC (MVDC) grid has drawn more interest in the application of traction and large-scale ships, for its lower loss, higher reliability, higher controllability and simpler system architecture. DC breaker and DC distribution are the key elements in the MVDC grid, and the power electronic transformers (PETs) have shown great advantage in the MVDC grid for its relatively smaller volume and higher flexibility compared to the traditional line transformers and AC/DC converters. In this study, a distribution DC PET based on input series output parallel dual active bridge (DAB) is proposed in the application of power supply system in traction and large scale ships. The DC PET consists of 12 DABs with an input voltage of 10kV and the output voltage of 380V. Strategies are proposed for distributed voltage balancing and redundancy control in the proposed PET. Simulations were done in MATLAB/Simulink. In the simulation, waveforms in the normal working conditions and the module fault status is shown, and the result shows that the proposed DC PET has great controllability and flexibility and by adding redundant modules, it keeps great reliability while fault occurs.