Research on Power Electronic Transformers Based on Virtual Synchronous Machine Control

In order to achieve the goal of friendly interface between microgrid and powe system main network, this paper studied a cascaded II-type Power Electronic Transformers (PET) scheme which use virtual synchronous machine control. After analyzing the main circuit topology and working principle of PET, this paper explained the implementation process of the control strategy based on the Synchronverter virtual synchronous machine, and introduced the cascaded II-bridge voltage equalization control to further achieve the effect of stable output voltage. Finally, the paper built a system simulation model based on Matlab/Simulink. The simulation results show that the PET scheme studied in this paper can not only adjust autonomously in response to changes of Microgrid voltage and frequency, but also can provide support for the voltage and frequency stability of the main grid of the power system.