An Enhanced Average Value Model of Modular Multilevel Converter for Accurate Representation of Converter Blocking Operation

Modular Multilevel Converter (MMC) has demonstrated significant advantage in harmonic elimination and improved converter efficiency due to the use of large number of submodules and low switching frequency of the submodules. However, the massive switching events of the Insulated-Gate Bipolar Transistors (IGBTs) in the MMC have also introduced high computational burden when modelling the MMC in electromagnetic transient tools. Various research efforts have dedicated to developing the numerically efficient average value models (AVMs) for the MMC. This paper gives an overview of the existing control signal based AVMs of the MMC and proposes an enhanced average value model with arm current initialization method to compensate for the initial condition issue in the previously developed AVMs. The proposed approach is evaluated in a point-to-point MMC HVDC system under Simulink/eMEGAsim environment.