Design of a single stage grid-connected buck-boost photovoltaic inverter for residential application

This article introduces the design of a three-switch single-phase single-stage grid-connected buck-boost photovoltaic inverter topology for residential applications. The proposed design topology has numerous desirable features such as better utilization of the photovoltaic array, low cost, compact size, simpler control and higher efficiency. For switching of inverter power circuit, we used a combination of sinusoidal pulse width modulation (SPWM) and square wave signal under grid synchronization condition. Moreover, to control SPWM duty cycle and to regulate the inverter's instantaneous ac output current, a closed-loop SPWM control scheme is employed to stabilize the output as fast as possible. The design and analysis of the inverter control circuit and grid synchronization methods are portrayed in detail. The proposed design is mathematically modeled which is simulated in PSIM. Finally, the simulation results are presented to verify the viability of the proposed single-stage three-switch buck-boost inverter for grid-connected photovoltaic application and confirmed the capability of the inverter to feed a sinusoidal current to the utility grid at a wide range of input photovoltaic dc voltage.