Measurement and simulation of current total harmonic distortion on three-level single phase 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, respectively. The transformerless PV inverter is installed in front of Centre of Excellent for Renewable Energy (CERE), 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 AC three-level waveform and CTHD of the loads are measured using PM 300 analyzer. A simulation of CTHD on three-level transformerless PV inverter is done for the same loads using PSpice software. CTHD measurement and simulation validation are tested using statistical analysis. The simulation result shows that the value of CRM is closer to zero which indicates that the simulation is perfectly simulated, the values of RMSE are low value, this indicates that the simulation performs well, the value of NSE is closer to 1 which indicates that the simulation match perfectly with the measured CTHD. The lowest CTHD of 15.448% and 11.75% are obtained when the maximum voltage angle are 1340 and 1250 for measurement and simulation, respectively.