Research on the Simplified Model of Modular Multilevel Converters

This paper introduces a novel simplified model based on mathematical functions for modeling the steady-state and the dynamic behavior of Modular Multilevel Converter (MMC). The large number of switches in MMC creates a computational challenge for electromagnetic transient simulation programs, as it is extremely time consuming. The proposed model decreases the order of system's admittance matrix and derives an equivalent function of bridge arm based on capacitor voltage balancing strategy. Simulations are carried out which shows that both the transient and steady-state response of the simplified model well match that of the detailed one. The simplified model is validated to be effective and provides a method for analyzing high level MMC systems.