Grid-connected operation and control of single-phase asymmetrical multilevel inverter for distributed power generation

In recent times, multilevel inverters (MLIs) are gaining popularity for grid integration of distributed power generation sources. In this paper, a proportional-resonant (PR) controller based on current control logic is proposed for a single-phase eleven-level inverter topology, enabling the integration of distributed power generation sources into the grid. The presented topology utilizes eight two-quadrant switches and three dc sources to produce an eleven-level output voltage. The level-shifted pulse width modulation (LS-PWM) scheme is used for providing switching signals to the inverter under grid-connected operation. Simulation and real-time results are presented for the eleven-level inverter to validate the presented current control logic under the grid-connected mode of operation. The hardware-in-loop emulator (Typhoon HIL-402) is used for taking real-time results of the presented grid-connected topology. The total harmonic distortion (THD) of the eleven-level inverter voltage and grid current is 12.10% and 0.46%, respectively. The efficiency of the inverter while supplying 2 kW active power to the grid is 98.4%.