Control Method of Current Control based Power Conditioning System Applying Modular Multilevel Converter Structure

In recent years, distributed power generation systems of photovoltaic (PV) have become widespread, and a demand for higher performance of a power conditioning system (PCS) that converts DC power generated from PV system into AC power increases. It is important for the PCS operation to obtain proper current control for accurate active and reactive power flow control. On the other hand, modular multi-level converter (MMC) has attractive circuit configuration for high voltage and multi-level output and is widely studied and developed. In this study, the PCS is applied for the MMC circuit configuration and its control method including the current control for input and output current is proposed. The control scheme is explained and the operation is verified in simulation and experiment using a mini-model of the MMC type PCS.