Optimization of Current Total Harmonic Distortion on Three-Level Transformerless Photovoltaic Inverter

Abstract

This paper presents a new topology of three-level transformerless photovoltaic (PV) inverter. It consists of three main circuits; they are a pulse driver circuit, a full bridge inverter circuit and a power factor correction circuit that have functions as production of pulse waves, to develop alternating current (AC) waveform and to stable voltage of PV array. The transformerless inverter is installed in front of Electrical Energy and Industrial Electronic Systems (EEIES) Cluster, Universiti Malaysia Perlis, Northern Malaysia. Its main energy source is a PV array that consists of three unit PV modules, each unit has 81 V, 60 W. In this research, optimization of current total harmonic distortion (CTHD) on AC three-level waveform transformerless PV inverter is developed and created by a microcontroller PIC16F627A-I/P with change maximum voltage angle of the AC three-level waveform from 200 to 1800. Resistive load of 30 W lamp and inductive load of 20 W water pump are applied to the transformerless PV inverter. The result shows that the less CTHD of 15.448% is obtained when the maximum voltage angle is 1340.