Power Balance Strategy of Cascaded DC Solid State Transformer Based on Virtual Impedence

The traditional DC solid state transformer (DCSST) needs to consider the decoupling between the two control targets, and it is impossible to achieve the terminal voltage matching of a single module to achieve the efficiency optimization. In this paper, the cascaded topology can solve the above problems well, and under non-ideal conditions, the virtual impedance is introduced to suppress the system circulation and achieve the power balance of each module. Firstly, the working principle, power characteristics and control strategy of the circuit are analyzed theoretically. At the end of the paper, the simulation waveform is given to verify the effectiveness of the scheme.