Power module voltage balancing method for a ±350 kV/ 1000 MW modular multilevel converter

In this paper, a power module capacitor voltage balancing method is presented for a ±350 kV/ 1000 MW modular multilevel converter (MMC) oriented for a back-to-back grid interconnecting project. In this method, a Balancing Adjusting Number (BAN) is proposed to adjust the voltage balancing effect and the switching frequency of the power modules. An accurate switching frequency calculation method is also presented. Verification results show the effectiveness of the proposed voltage balancing method and the correctness of the switching frequency calculation method.