The research of coordination control strategy in cascaded multilevel solid state transformer

This paper discusses a solid state transformer (SST). The solid state transformer consists of a cascaded multilevel AC/DC rectifier, Dual Active Bridge (DAB) converters with high frequency transformers and a DC/AC inverter. A single phased d-q vector controller is applied in the rectifier stage, a voltage balance control method and a power balance control method are applied in SST. At last, a fundamentally experimental prototype is implemented. The experimental results verify the feasibility and effectiveness of the overall control strategy.