Simplified Reactive Power Control of a Multilevel Inverter for Grid-Connected Photovoltaic Applications

Photovoltaic generation has grown with continuous developments that allow new functionalities such as power factor correction or multilevel voltage generation. However, the increment in the complexity of control algorithms requires expensive digital systems for their correct implementation. Therefore, this paper presents a new simplified reactive power control technique based on the d-q rotating frame theory allowing power factor correction by injecting phase-shifted or in-phase current to the power grid from photovoltaic arrays. Furthermore, the high conversion efficiency rate result is due to the use of an MPPT algorithm. Finally, the proposed simplified reactive power control was constructed to be used in a 7-level H-bridge power inverter. Simulated results of the proposed simplified control scheme verify low-THD in the current and a high-performance during active or reactive power injection into the single-phase electrical grid.