General Solar Panel Output Parameters measured during flash test
Output parameters help both manufacturers and buyers to compare the performance potential of solar modules and calculate their efficiency according to our requirements. There are different key parameters to determine the output performance of a solar PV module:
1. VOC (V), open-circuit voltage. PV Modules are rated at two voltage levels: the first is called Voltage of Open Circuit (VOC). The voltage output of the module is measured with the module disconnected from any load.
2. VMP (V), voltage at maximum power point, the second voltage rating point is called Voltage at Maximum Power Point (VMP) and is the voltage at which the module puts out the most power.
All voltage measurements are made at the module’s electrical terminals mounted on the module’s back. These measurements are made with a highly accurate voltmeter.
3. ISC (A), the short-circuit current, current is also rated at two important levels: The first is called Short Circuit Current (Isc) and is the amount of current that the pv module supplies into a dead short.
4. Imp (A), Current at maximum power point, the second current rating is called Current at Maximum Power Point (Imp) and is the number of Amperes delivered by the module at its maximum power point.
5. Pm (W), Maximum Power and Maximum Power Point, power is equal to Amperes times Volts (P=IE, or Watts=Amperes multiplied with Volts). Every module has a specific point on its power curve where the product of Amps times Volts yields the greatest Wattage.
This is the Maximum Power Point, and the module’s wattage output is rated at this point’s voltage and current. In order to find the module’s maximum power point, the flash test takes data over the entire range of voltage and current.
This way the wattage for each Current and Voltage data point can be calculated. By doing this we can find the Maximum Power Point in these Current versus Voltage data.
6. FF (%), Fill Factor, the Fill Factor is defined as the maximum power produced (at MPP) divided by the product of ISC and VOC. One can see that the Fill Factor will always be less than 1. Due to the difficulties in measuring conversion efficiency quickly, it is common to measure the fill factor instead.