Closed Loop operation of Transformer-less Inverter in Voltage and Current Control mode

A single stage single phase inverter topology derived from Cuk converter, with an input switched inductor, suitable for Photovoltaic-Grid interface is implemented in voltage control and current control mode. Voltage and current control strategies, controller tuning with d-q transformation for active power injection to grid and how it was validated by simulation are detailed in the paper. Simulation results are presented for a power level of 250W, then tracking the voltage/current reference was observed in standalone and grid connected mode of operation individually. The proportional and integral constants of the current controller is calculated based on the value of the output filter inductor and External Series Resistance (ESR) of the output filter capacitor. These calculated values gave good results as presented. Additionally, total harmonic distortion was measured to be less than 2% for a voltage gain of 3.42.