Misalai Solar PV?
Babu da zan iya bayar da aiki na biyu mai ma'ana daga karamin shamsi. Saboda haka, don samun darajar da aikin PV system, ya kamata a gudanar da adadin PV solar cells. Module ta shamsi ana gudanar da adadin karamin shamsi a cikin siri masu ma'ana da aikin daraja. Wani module ta shamsi zai iya haɗa daga 3 watts zuwa 300 watts. Modules ta shamsi ko modules ta PV suna da aikin bayanin babban tashar aikin shamsi.
Akwai karamin shamsi PV wanda yake bayar da aiki na biyu mai ma'ana wanda yana cikin 0.1 watt zuwa 2 watts. Amma ba zai fi karfi a yi amfani da wannan aiki na biyu mai ma'ana a matsayin banga na system. Saboda haka, an gudanar da adadin kamar haka don samun unit mai ma'ana da ake amfani da shi a jami'a wanda ake magana ne a cikin solar module ko PV module.
A cikin module ta shamsi, karamin shamsi suka gudanar da su a cikin siri kamar halayen battery cell units a cikin battery bank system. Yana nufin cewa terminalen positive ta wani cell suka gudanar da terminalen negative ta cell na biyu. Tushen voltage ta module ta shamsi ita ce sum of voltages ta individual cells connected in series in the module.
Voltage na biyu na shamsi na karamin shamsi ita ce approximately 0.5 V, saboda haka idan 6 kamar haka suka gudanar da su a cikin siri, tushen voltage ta cell ita ce 0.5 × 6 = 3 Volt.
Ratings of Solar Module
Output daga module ta shamsi tana da muhimmanci ga wasu abubuwa kamar temperature da intensity of incidence light. Saboda haka, rating ta module ta shamsi ya kamata a bayyana da cewa tana da wasu abubuwa. Ita ce standardized practice to express rating of PV or solar module at 25oC temperature and 1000 w/m2 light radiation. Modules ta shamsi suna da ratings su da output open circuit voltage (Voc), short circuit current (Isc) and peak power (Wp).
Yana nufin cewa waɗannan uku abubuwa (Voc, Isc and Wp) zai iya bayar da module ta shamsi a cikin 25oC and 1000 w/m2 solar radiations.
Waɗannan abubuwa, 25oC temperature and 1000 w/m2 solar radiations, suna da Standard Test Conditions.
Standard Test Conditions ba zai da shiga a lokacin da za a gudanar da modules ta shamsi. Saboda haka, solar radiations and temperature tana da dace a lokacin da wurare.
V-I Characteristic of Solar Module
Idan muna kirkiro chart ta V-I daga module ta shamsi, tushen X-axis ita ce voltage axis and Y-axis ita ce currents. Tushen chart ita ce V-I characteristic of a solar module.
Short Circuit Current of PV Module
Under Standard Test Condition, terminals of a solar module are short circuited, then the current delivered by the module is short circuit current. Bigger value of this current indicates betterness of the module.
Although under standard test condition, this current also depends upon the area of the module exposed to the light. As it depends upon area, it is better to express by short circuit current per unit area.
This is denoted as Jsc.
Hence,
Where, A is the area of the module exposed to the standard light radiation (1000w/m2). Short circuit current of a pv module also depends upon solar cell manufacturing technology.
Open Circuit Voltage (Voc)
The voltage output of a solar module under standard test condition, when the terminals of the modules are not connected with any load. This rating of solar module mainly depends upon the technology used to manufacture solar cells of the module. More Voc indicates betterness of the solar module. This open circuit voltage of a solar module also depends upon operating temperature.
Maximum Power Point
This is the maximum amount of power which can deliver by the module Under Standard Test Conditions. For a fixed dimension of a module higher the maximum power better the module. Maximum power also called peak power and this is denoted as Wm or Wp.
A solar module can be operated in any voltage and current combination upto Voc and Isc.
But for a particular current and voltage combination under standard conditions the output power is maximum. If we proceed through y-axis of the V-I characteristic of a solar module, we will find the power output increases nearly linearly with current but after a certain current power output will fall down as it approaches to the short circuit current as at short circuit condition the voltage is considered to be ideally zero across the terminals of the solar module. So it is clear that maximum output power of a solar module does not occur at maximum current i.e. short circuit current instead it occurs at certain current which is less than short circuit current (Isc). This current at which maximum output power occurs is denoted as Im.
Similarly maximum power of a solar cell does not occur at open circuit voltage as it is open circuit condition and current through the cell is considered to be ideally zero, at this condition. But similarly as previous case, maximum power in a solar module occurs at a voltage lower than open circuit voltage (Voc). The voltage at which maximum power output occurs is denoted as Vm. The maximum power of a solar module is given as
The current and voltage at which maximum power occurs are referred as, current and voltage at maximum power point respectively.
Fill Factor of a Solar Module
Fill factor of a solar module is defined as the ratio of maximum power (Pm = Vm x Im) to product of open circuit voltage (Voc) and short circuit current (Isc).
Higher the Fill Factor(FF), better is the solar module.
Efficiency of Solar Module
