Semiconductor loss reduction in a Modular Multilevel Converter by harmonic injection to the reference voltage

Modular Multilevel Converter (MMC) acts as an energy interface in high-power applications. Due to large number of switches, it is an important goal to measure the amount of losses in the converter. This paper presents an analytical loss calculation approach based on current and voltage waveforms of switches. Applying the device parameters as well as the current and voltage waveforms, the proposed method calculates the expected loss behavior. By injecting a specific amount of second harmonic into the reference voltage, the converter losses are reduced and the efficiency of the converter is improved. The simulation results of applying the proposed method to a three-phase MMC clearly prove its efficient performance.