Design of a transformer-less single switch-mode photovoltaic grid-connected boost inverter with immittance conversion topology

This article introduces the design of a transformer-less single-switch mode (SSM) photovoltaic grid-tie boost inverter (GTBI) with immittance conversion topology for residential applications. The proposed GTBI employs only an SSM boost inverter circuit along with a T-LCL immittance converter. As the proposed design is entirely transformer-less with SSM boost inverter, it significantly reduces the Total Harmonic Distortion (THD) to less than 0.2%, minimizes the size of the inverter and increases the inverter efficiency to more than 99%. The design and analysis of the inverter´s SSM gate control circuit and grid synchronization techniques are portrayed in details. The proposed design is mathematically modeled and simulated via PSIM software. Finally the results are presented and discussed to confirm the effectiveness of this grid-connected SSM boost inverter.