Capacitor voltage control method suitable for hybrid modular multilevel converter

According to the capacitor voltage control method suitable for the hybrid modular multilevel converter, the optimal point limitation of AAMC energy balance is expanded through current commutation modulation and capacitor voltage compensation control, and the voltage regulation range is expanded. In addition, the influence of a commutation interval caused by bridge arm inductance on energy balance can be solved. Firstly, a switch module in a bridge arm is adjusted through a current commutation modulation method, so that the switch module is switched at a bridge arm current zero crossing point; and the current commutation process is analyzed and deduced in detail through an analytical expression. And the mechanism of capacitor voltage drop caused by the rectification process is further clarified, and a theoretical basis is provided for the design of the controller. On the basis, voltage compensation control of capacitor voltage drop is provided, so that normal work of the capacitor in four quadrants is realized