A Comparative Performance Analysis Between the Buck and Boost Differential Single-Phase Inverters with Active Power Decoupling

Differential single-phase inverters offer the advantage of achieving active power decoupling without adding additional semiconductor devices. This paper presents a comparative performance analysis of two types of differential single-phase inverters with active power decoupling: a single stage differential boost topology and a two-stage differential buck topology. The targeted applications are small photovoltaic power plants, which typically require boosting the input voltage. The aim of this research is to evaluate the two topologies in terms of voltage and current stresses and losses, under various operating conditions, and taking as reference a conventional H-bridge inverter. The analysis includes the mathematical description of each topology, which is later used to implement the control and to establish the voltage and current limits. Between the two topologies, differential boost inverters can simultaneously achieve both DC input voltage boosting as well as generate output AC voltage waveforms using a single-stage topology. This offers the advantages of a low component count and high-power density. However, it experiences higher voltage and current stresses when compared to the differential buck inverter with an additional DC-DC input boost stage. These stresses ultimately impact efficiency, and as a result, the differential buck inverter exhibits a higher efficiency compared to the differential boost inverter.