School of Engineering and Technology
PV Solar Cell Simulation
Assignment 1
By Matoug Abuzmila (08021258) Submitted To Dr. Rob Miles
1
AIM
“The aim of this assignment is to simulate the behaviour of a photovoltaic solar cell and hence to determine how the short circuit current (photocurrent ) and open circuit voltage vary with light intensity, how device efficiency is affected by series resistance and how short circuit current, open circuit voltage, fill-factor and solar conversion efficiency are affected by the choice of semiconductor used to make the solar cell “
Introduction A solar cell is an electrical component that converts to sunlight to electrical energy. Solar cells are made of variable semiconductor materials. Semiconductors are conduct electricity when the heat or light is more, and they perform as electrical insulation at low temperature. Many semiconductor switches are available with high working frequency and power rate which can complete energy convert with high efficiency. The P V system can be used for homes, offices and public building. Also the estimated life for a PV model is 30 years. When the system of PV decrease of the cost of solar cells, there is increase significance in photovoltaic system application. Electric motors powered by solar cell generators are one of the most important applications, as water pumping systems. The people can be control the sun energy in many other different ways, such as transportation and electricity generation and convert the sun’s energy to a fuel, which can be used for heat, transportation and electricity.
2
The system (PV) is an easy method of controlling the sun energy. PV as a device (Solar Cells) is only in that they directly convert the case solar radiation into electricity. “Today it is a rapidly growing and increasily important renewable alternative to conventional fossil fuel electricity generation” The first practical photovoltaic devices are started in the 1950s, research and development of photovoltaic. “In the 1980s” research into silicon solar cell paid off and solar cells are begun to increase their efficiency. In 1985 silicon solar cells achieved the target of 20% efficiency. The photovoltaic industry skilled steady increase rates of between 15% and 20%, and the year 1997 maxim a growth rate of 38% and today solar cells have recognized not only as a mean for providing power, finally many countries used solar cells, because the solar cell is very useful for invaerment and shaper than any source for energy ,that’s why all the countries looking for this source .
3
The figure show solar circuit From. (www.chuck-wright.com (www.chuck-wright.com)) Teacher notes 3.
4
The curve voltage and current of the solar cell diode has affected relationship between phase shift and power extracted from the diode. So many cases. First. “With illumination, solar has the same electrical characteristics as a large diode.”When the sun light is shifted on fourth quadrant as the create to generator power, the light intensity is increased the mount of shift also is increased .so the relationship between intensity and the mount of shift is directly. 5
Open circuit voltage ,Voc . When the current through the device is zero, it be occurred maximum voltage at this point in the curve, also the power output is zero because the current is zero. Short circuit The short circuit (I sc ) is occurred when the voltage across the solar cell is equal zero .The short circuit in the solar cells depends off: 1) The The area area of of solar solar cell cell.. 2) Density. 3) The The numb number er of of phot photon on.. 4) The The visu visual al prop propert erties ies.. IL is generated current inside of solar and I SC short circuit is Exceedingly measured current . Not exactly but is approximately. FILL Factor FF is a defined a ratio between maximum power (Pmx) and input Power (Pin). FF
Where: Vmx = maximum voltage. Imx = current maximum. Isc
= short circuit current.
Voc = open circuit voltage. If the current and power in the solar cell are reduced there is a small for lower FF. As FF is possible measure of the square area under the curve of voltage and current, also the fill factor as percentage. Efficiency. Efficiency is defined as the ratio between output power and input power. The efficiency is related with V oc and ISC using FF. “The efficiency depends on the spectrum and intensity of the incident sunlight and the temperature of the solar cell”.
6
.
So the efficiency is:
Where:
ISC = Short circuit current. Voc = open circuit voltage. FF = Fill factor η = Efficiency.
Notes: Efficiency is as a percentage, so it doesn’t need unit.
Series resistance. The main purpose of series resistance is to decrease the fill factor and short circuit current, when the open voltage circuit the series resistance doesn’t effect in the current flow through the solar cell.
10) Effect of temperature. Any solar cells are responsive to temperature, when the temperature is increased the band gab of the semiconductor is decreased, so the temperature is inversely proportional with band gab of the semiconductor. In open circuit the voltage (V oc ) is decreased and the current (ISC ) is a little increased, because the temperature high also the temperature depends of I O .
7
FF
8
