Power loss model and efficiency analysis of grid-connected seven-switch boost-type photovoltaic current source inverter using two power switches configurations

The topology of grid-connected seven-switch boost-type current source inverter (CSI7) is a promising alternative to the conventional six-switch current source inverter (CSI) due its superiority in terms of reliability and energy efficiency. It is a simple single-stage boost-type converter that allows the injection of high quality sinusoidal AC-currents with controllable power factor into the grid with a DC-link voltage lower than the grid voltage amplitude. This paper evaluates the performance of grid-connected photovoltaic (PV) CSI7 in terms of power losses and efficiency considering distinct configurations of the voltage reverse blocking power switches, i.e., silicon IGBTs (Si-IGBTs) in series with hyper-fast recovery silicon diodes (Si-HFRDs) and Si-IGBTs in series with wide band-gap silicon-carbide Schottky-barrier diodes (SiC-SBDs). The proposed investigation is based on experimental tests and combined electrical-thermal computer co-simulations using PLECS and simulink. The obtained results empathize the features of SiC-SBDs based power switches in terms of reducing the inverter’s power losses and improving the overall system efficiency. They also demonstrate the high performance of the CSI7 topology in terms of power quality in grid-connected PV applications.