Three-Phase Transformer-less Hybrid-Bypass Inverter

This paper proposes a three phase transformer-less inverter to reduce the common mode voltage with hybrid AC/DC bypass circuit in the PV inversion system. The proposed inverter has the advantages of low conduction losses compared to the traditional three phase DC bypass inverter. The fluctuation range of the common mode voltage can be reduced to 1/3 of the traditional inverter. Thus, the leakage current will be significantly suppressed. Also, a variation topology of the proposed inverter is shown in this paper. The detailed comparison between the proposed inverter and the traditional three phase three level inverters reveals that the proposed inverter saves 3 switches compared to the NPC inverter and has less conduction losses compared to the DC bypass inverter.