Modeling of Single Stage Grid-Connected Buck-Boost Inverter for Domestic Applications

This paper introduces the implementation of conventional multistage inverter into single-stage grid-tie buck-boost photovoltaic inverter topology for domestic purposes where Buck-boost and inversions are takes place in single stage only. Instead of using transformer here we will use special energy conversion device called Coupled Inductor. And this topology has a low component count with only three power switches, while conventional PV inverters may require four to five switches in two-stage power conversions for the same functions. And also it has numerous desirable features such as low cost, smaller size, simple control scheme and good efficiency. Switching of inverter circuit will be done by combination of sinusoidal pulse width modulation (SPWM) and square wave signal under grid synchronization condition. To regulate the inverter’s instantaneous ac output voltage, a closed-loop SPWM control technique is used to stabilize the output and to regulate the inverter’s instantaneous ac output voltage. The proposed model design is mathematically modeled in MATLAB or PSIM. Simulation results are presented to verify the viability of proposed inverter for grid connected photovoltaic application and shows the capability of the inverter to feed a sinusoidal current to the utility grid at wide range of input photovoltaic dc voltage.