PROJECT TITLE :

A Single-phase PV Quasi-Z-source Inverter withReduced Capacitance using Modified Modulationand Double-Frequency Ripple Suppression Control - 2016

ABSTRACT:

In single-section photovoltaic (PV) system, there's double-frequency power mismatch existed between the dc input and ac output. The double-frequency ripple (DFR) energy desires to be buffered by passive network. Otherwise, the ripple energy can flow into the input facet and adversely affect the PV energy harvest. In a conventional PV system, electrolytic capacitors are usually used for this purpose due to their high capacitance. However, electrolytic capacitors are considered to be one of the foremost failure prone parts in an exceedingly PV inverter. During this paper, a capacitance reduction control strategy is proposed to buffer the DFR energy in single-phase Z-source/quasi-Z-supply inverter applications. While not using any additional hardware elements, the proposed management strategy can significantly reduce the capacitance requirement and achieve low input voltage DFR. Consequently, highly reliable film capacitors can be used. The increased switching device voltage stress and power loss due to the proposed control strategy can conjointly be discussed. A 1-kW quasi-Z-supply PV inverter using gallium nitride (GaN) devices is made in the lab. Experimental results are provided to verify the effectiveness of the proposed methodology.