Cascaded 3-Phase-Bridge Converter Based on Virtual Synchronous Generator Control

in photovoltaic medium voltage three-phase high-power power generation, the multi-level cascaded 3-phase-bridge (C3PB) converter is used to replace the traditional single-phase cascaded H-bridge (CHB) converter in this paper. The virtual synchronous generator is proposed to control the cascaded three-phase bridge converter to solve the problem of frequency fluctuation in isolated island operation of microgrid. In addition, in order to further improve the waveform quality, the carrier phase-shifted PWM (CPS-PWM) is used as the switching strategy of the converter. VSG based CPS-PWM realizes the small fluctuation of system frequency, the smoothness and stability of voltage and current waveforms when large load switching or power changes. Finally, the feasibility and practicability of the method are verified by simulations.