A small scale photovoltaic system for decentralised electricity grid

• Main Author: Teong, Gek Tee
• Other Authors: Wong Kin Shun, Terence
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/64230
• Institution: Nanyang Technological University

PV system is a form of clean and renewable energy source. PV module converts solar energy from the sun to electricity. The electricity produced is dependent on sun irradiance and temperature. Thus power electronic converters are required to regulate and manage the electrical energy produced by PV. The objective of this FYP is to design and built a small decentralized PV system which consists of power electronic converters that can produce both DC and AC electrical sources. The PV used for this FYP was the crystalline silicon type, with an output voltage of 14.5Vdc and rated power of 45w. To produce a 12Vdc source, the DCDC buck converter was built to step down the 14.5Vdc. A 555 IC was used to generate the duty cycle required to drive the switch of the buck converter. As the output voltage of PV module is not constant, an additional boost converter was designed and built. The aim was to have a constant 15Vdc to charge a 12v lead acid battery, as well as to provide a constant source for the buck converter to step down voltage to a constant 12Vdc. The constant 15Vdc can be achieved by using a simple PWM to drive the MOSFET of the boost converter. PSim simulation software was used to analyse the PWM design. A charge controller was also built with the intention to trigger and monitor the charging of the lead acid battery. The charging voltage is within the range of 14.4 Vdc to 15Vdc. Finally the transformer based single phase inverter was built for converting the dc voltage from the battery and DCDC converters to a targeted 230Vac at 50Hz. The 555 IC was used to determine the frequency of the inverter’s output voltage. With these converters could be made better with the maximum power point tracking controller. The Perturb and Observe MPPT method could be considered for future implementation.