Common Mode Voltage Suppression Method for Third-Harmonic Injection Two-Stage Matrix Converter in Low Modulation Ratio

To resolve the problem of high-frequency and high amplitude common mode voltage (CMV) in third-harmonic injection two-stage matrix converter (3TSMC), a CMV suppression method based on selecting the inverter stage vector group with the lowest CMV amplitude is proposed. This method reduces the voltage amplitude and the high-frequency component of the CMV without additional hardware. Firstly, a method for selecting appropriate inverter stage vectors based on the state of input voltage selector is introduced. Then, the influence of the dead zone of the inverter stage bridge arm on this method is analyzed, and the sector division of the inverter stage is adjusted to weaken the influence of the dead zone. Finally, the effectiveness of the proposed method is verified through experiments.