Switching Logic Based Current Control of a Single Phase Unipolar Grid Connected Inverter At Constant Switching Frequency

In a grid connected system, the inverter is an essential component and must be regulated appropriately to ensure the power system’s quality. To regulate the output current of a single phase unipolar grid connected inverter, a new current control method is recommended here. A sinusoidal reference wave, along with the switching logic is used in this method for the current control. Depending on its slope, the reference current or the switching logic controls the inductor current’s rise and fall. The sinusoidal reference current regulates the steep slope of the inductor current, whereas the switching logic controls the moderate slope. Modifying the sinusoidal reference further improves the inductor current obtained with the recommended control logic. This current control method offers peak current limiting while guaranteeing constant switching frequency. Thus, the recommended control method is comparable to the Hysteresis Current Control method except for the band. The shortcoming of the conventional Hysteresis Current Control method is addressed here while retaining its merits. The control concept is theoretically analysed and verified by simulation. The results are presented to validate the new method.