PV*SOL Expert 6.0 - Manual - Valentin Software
PV*SOL Expert 6.0 - Manual - Valentin Software
PV*SOL Expert 6.0 - Manual - Valentin Software
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<strong>PV*SOL</strong> <strong>Expert</strong> <strong>6.0</strong> - <strong>Manual</strong><br />
If the PV output is larger than the inverter’s nominal output, the inverter must reduce the<br />
output to the inverter’s nominal output. If the PV output is significantly less than the<br />
inverter’s nominal output, the inverter works at a low efficiency rate.<br />
MPP Voltage Check<br />
The inverter’s MPP tracking field is compared with the MPP voltages of the modules<br />
connected in series. The voltage decreases with rising temperature and decreasing<br />
radiation.<br />
Boundary values in defining the MPP voltages that occur in the PV system are:<br />
106<br />
• a working point for high irradiation and low temperature to define the maximum<br />
MPP voltage, and<br />
• a working point for low irradiation (onto the tilted module surface) and maximum<br />
module temperature to calculate the minimum MPP voltage.<br />
The working points are dependent on the:<br />
• location of the system,<br />
• orientation and inclination of the modules, and the<br />
• type of module mount.<br />
<strong>PV*SOL</strong> ® takes the lowest module temperature as being equal to the lowest external<br />
temperature in the climate data record being used. Maximum radiation is taken from the<br />
climate data record for the month in which this temperature occurs, for the preceding<br />
month, and for the following month, and is converted onto the tilted module surface. For<br />
example, with an orientation due south and a 30 inclination, the values for two different<br />
locations are:<br />
• Berlin: 14 C und 858 W/m²<br />
• Freiburg: 11 C und 957 W/m²<br />
To define the system’s lowest MPP voltage, the value of the irradiation during module part<br />
load performance is taken from the module database as the minimum irradiation. For<br />
example: 300 W/m².<br />
The maximum module temperature for this irradiation is defined by the maximum<br />
temperature at the system location plus an offset. The maximum system location<br />
temperature is read from the climate data record being used. The offset is dependent on<br />
the module mount and the irradiation.<br />
It applies that:<br />
Tmax,Modules = Tmax,Sys. Location + factor * Gmin / 1000.<br />
Factor = 20 for free-standing modules,<br />
Factor = 30 for rooftop mounting with ventilation space, and
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