Common-Ground Double Gain Five Level Inverter for Distributed Energy Resources

A common-ground transformer-less five-level (5L) inverter topology is presented in this research with a voltage-boosting ability of four times compared to the typical neutral point clamped multi-level inverter topologies for single and three-phase distributed energy resources. The proposed topology depends on flying capacitor operation and requires ten active power semiconductor switches and two flying capacitor units per leg. A simple level-shifted sinusoidal pulse width modulation strategy is employed to self-balance the flying capacitors, while also mitigating the output current ripples and lowering the filter rating. The merits of the proposed five-level inverter topology are: (i) no leakage current in the industrial system due to the common ground operation; (ii) the input DC link voltage requirement is half of the grid voltage peak, whereas the neutral point is clamped; and (iii) the capability of reactive power compensation. The principles of operation, modulation techniques, and steady-state analyses for the proposed inverter topology are discussed. The proposed inverter topology is validated through both the MATLAB/Simulink and PSIM platforms. To analyze the effectiveness of the proposed inverter architecture, loss distribution, current and voltage stress across the switches, and efficiency of the inverter topology are provided.