A Novel Model Predictive Control for Three-Phase Split-Source Inverter with Reduced Common-Mode Voltage

Split-source inverter (SSI) is appropriate for transformerless applications with low input voltage. The common-mode voltage (CMV) can cause destructive effects in systems without galvanic isolation. This paper focuses on mitigating CMV and improving the performance of three-phase SSI by employing the finite-set model predictive control (FS-MPC). The proposed algorithm is simplified by controlling only output currents, eliminating weighting factors from the cost function. In three-phase SSI, the zero vector, which is associated with inductor charging mode, causes the negative peak of CMV. Thus, to decrease the peak-to-peak value of CMV, it is replaced by two active vectors with opposite directions. These vectors are chosen based on minimizing switching losses and changes in CMV. By this method, the CMV peak-to-peak value is decreased by 50% compared to the conventional approach. Additionally, the total harmonic distortion (THD) of output current is improved. The effectiveness of this method is verified by simulation results.