Novel Multilevel Inverter Based Standalone PV System Using Reduced Number of Components

Abstract

Research effort to develop new multilevel inverters (MLIs) for the photovoltaic (PV) system is emergent. The conventional MLI consists of a large number of switches and diodes. Due to this, the power losses increase and the overall system efficiency decreases. In this work, two novel MLI structures (DS1 and DS2) are introduced. The DS1 and DS2 structures are interfaced with PV system through a single-switch single-inductor single-input multiple-output dc-dc converter. The output capacitances of the dc-dc converter are self-balanced without employing any closed-loop control. Both the DS1 and DS2 structures consist of an equal number of components for generating a seven-level output. However, DS1 does not possess reactive power handling ability unlike the DS2. Both the structures are compared with the state-of-art MLIs in terms of the number of switches, number of diodes, and reactive power handling ability. After analyzing the structural functioning of both the MLIs, selective harmonic elimination (SHE) modulation technique is discussed that is further used to control the MLI. The structure DS2 is simulated with PV system and experimentally verified considering a similar rating system.