Photovoltaic powered uninterrupted power supply based on PIC microcontroller

Abstract

This thesis presents the photovoltaic (PV) powered uninterrupted power supply (UPS) system based on PIC microcontroller. The study of solar radiation is very important to know its potential to develop the PV powered UPS system. The PV powered UPS system should have a solar charger that can charge the battery fast, a change over of transfer switch that fulfill the standard of IEC 62040-3 and an inverter that has a lowest current total harmonic distortion (CTHD). For these reasons, the thesis objectives are to analyze the solar radiation potential to develop PV powered UPS system, to design a solar charger, a transfer switch and an inverter. The data of solar radiation are measured at the Renewable Energy Excellence Centre (REEC) Station, Universiti Malaysia Perlis in Kangar, Perlis, Northern Malaysia. The solar charger, transfer switch and inverter are constructed by PIC microcontroller. The results show that the average monthly solar radiation is 4824.81 Wh/m2. It is greater than 3000 Wh/m2 and indicates that the sky in Perlis is clear and the solar radiation intensity is very high. It indicates that the solar radiation in Perlis gives big potential for PV powered UPS system. The proposed solar charger can flow the charging current up to 24 A. It is due to the current can be divided in same value by the multiple current circuits. The proposed inverter technique is able to change peak voltage angle of the AC three-level waveform from 200 to 180'. An AC load applied to the PV powered inverter shows that the lowest CTHD is obtained when the peak voltage angle is 134'. A comparative study of CTHD between the proposed three level single phase PV inverter and the market three level inverters (2000 W power inverter, 2000 W Charger 10A SUVPR Series DY 2000C and 1000 W Charger 10A SUVPR Series DY 1000C) are conducted. The result shows that the CTHD of proposed three level single phase PV inverter is lower than the CTHD of the market three level inverters.