Modeling and operating characteristic analysis of MMC-SST based shipboard power system

Solid state transformer (SST) has the advantage of small size, high power density and low noise, which made it possible to use SST in shipboard power system (SPS). Due to the existence of various complex loads and poor working conditions, voltage instability and harmonic problems are caused inevitably in SPS. Amid at these problems, a new modular multilevel type SST (MMC-SST) based topology of SPS is proposed, which can effectively improve the DC bus voltage stability and the power quality. First, the topology of MMC-SST based SPS is analyzed. Then, the control strategy of MMC is discussed with its fault treatment capacity. Last, the simulation model is established and different working scenarios are considered to verify the feasibility and functionality of the proposed structure and control method. The results indicate that the new structure has good performance on stabilizing DC bus voltage, improving power quality and managing various loads.