A Modified Perturb-and-Observe Control for Improved Maximum Power Point Tracking Performance on Grid-Connected Photovoltaic System

Abstract

This paper deals with the control of maximum power production in a grid-connected photovoltaic system. The on-grid system ensures the continuity of electricity supply to consumers. It also offers less investment and operation cost due to the removal of battery requirements normally indispensable to guarantee supply continuity. To maintain the maximum output power production of photovoltaic panels regardless of changes in irradiation, proper control of the boost converter is necessary. The known perturb-and-observe method is explored and modified to improve performance. The modification is proposed by adding the measurement of the current variable to reduce the oscillation around the maximum power point once it is achieved. The connection to an existing single-phase alternating-current power grid is accomplished by implementing sinusoidal pulse-width modulation on the inverter. Phase-angle synchronization between the inverter output and the existing power grid is accomplished by using the phase-lock loop technique. Simulation of the proposed method showed that an improvement of the photovoltaic function up to 98% has been achieved.

Keywords

• boost converter
• grid-tie
• inverter
• maximum power point tracking (mppt)
• photovoltaic