Performance Comparison of Reactive Power Control Methods of Photovoltaic Micro-inverter

Abstract

Photovoltaic power generation becomes an important technology in recent year, because of its advantages such as clean energy, pollution reduction, no gas emissions, maintenance and operation requirements are low. So it is a new path for generating electric power. This paper will study the performance comparison of two photovoltaic systems of three-phase grid-connected micro-inverter and study their design methods of reactive power control. The first design is suggested that the photovoltaic PV system based on an interleaved DC-DC boost type converter with its maximum power point tracking control (MPPT) for each boost converter. A voltage source inverter type (VSI) is used as a three-phase micro-inverter. By controlling the direct and quadrature components of inverter output currents, reactive power controlling is achieved at 90.76% efficiency. The second design is suggested that the photovoltaic panel is connected DC-DC converter of an interleaved flyback type. Each sub-converter is controlled by an individual (MPPT). The circuit of active third-harmonic current injection in recent years have received much interest, this technique contributed to get better quality of current injected into the utility grid and to control the reactive power with good efficiency 95.07%. A line-commutate current source inverter type (CSI) with filter is used. The developed micro-inverter of (1000W) offers an expanded range of reactive power control with balanced three-phase output power. Each system design in this study has proven its effectiveness in obtaining control of reactive power and nearly sinusoidal three-phase output currents. The effectiveness of the suggested systems are clarified by using the MATLAB Simulink program and the results of the simulation show the validity of the suggested micro-inverter system.