Photovoltaic Panels and Solar Inverters - Everything You Need to Know about the Maximum System Voltage of a Photovoltaic Solar Panel and Why It Is Important
Contents
About the Maximum System Voltage
Example of Calculating the Compatibility of Solar Panels with an Inverter
Introduction - The Maximum System Voltage of a Photovoltaic Solar Panel and Why It Is Important
Photovoltaic panels are becoming increasingly popular as alternative and renewable energy sources for homes. But what does the maximum system voltage of a photovoltaic solar panel mean and why is it important?
What Does the Maximum System Voltage Mean in a Solar Panel?
The maximum system voltage found in the technical sheet represents the maximum voltage at which a solar panel system should operate to avoid damage. This aspect is crucial when connecting an inverter or controller to the solar panel array.
Why Is the Maximum System Voltage Important?
If the voltage provided by the solar panel array is too high, it will not function correctly and can cause damage to the system.
The inverter will fail or shut down when the system's maximum voltage exceeds the inverter's capacity.
How Is the Maximum System Voltage Calculated?
The maximum system voltage is calculated using a few simple steps and essential information from the photovoltaic panel manufacturer and local weather data. Here’s a step-by-step guide to do this:
Standard Testing Temperature (STC) of Solar Panels
This is the temperature used by solar panel manufacturers for testing and evaluation. It is usually indicated on the panel packaging or available in the manufacturer’s database.
Record Minimum Temperature for Your Region
This is the possible minimum temperature for your location. You can find these data in local weather statistics.
Temperature Coefficient of Open Circuit Voltage (VoC)
This coefficient determines performance according to temperature. It is indicated in the technical sheet of the panels.
Inverter Maximum Input Voltage
The inverter converts direct current from panels into alternating current. This information is found in the inverter's technical sheet.
Step-by-Step Calculator for Maximum System Voltage
Subtract the record minimum temperature from the STC temperature.
Multiply the result by the VoC temperature coefficient, then multiply by the module’s VoC.
Add the result to the module’s VoC to obtain VMax.
Divide the inverter's maximum input voltage by VMax and round the result to a whole number.
Multiply the number of modules by VMax to obtain the maximum system voltage.
Conclusion
With the correct information and our easy-to-use calculator, anyone can match the appropriate inverter or controller for their solar panel system. If you need additional assistance with installing solar panels at home or finding the right inverter, do not hesitate to contact us.
Key Takeaway
Ensuring that the maximum system voltage of solar panels is correctly calculated and compatible with the inverter or controller used is essential for preventing equipment damage and for the efficient operation of the entire solar system.
Evaluation of the Compatibility of a Bifacial Solar Panel with a Photovoltaic System that Includes a Solar Inverter
To evaluate the compatibility of a bifacial solar panel with a system that includes an inverter, we will perform some calculations to check if the system parameters fall within the specified limits. We have the following data:
Solar Panel Specifications:
Open Circuit Voltage (VOC) = 40V
Maximum Current (Isc) = 13.4A
Nominal Power (Pnom) = 435W
Inverter Specifications:
Nominal Power = 12kW
Maximum DC Input Power = 18kW
Maximum DC Input Voltage = 1100V
Nominal Input Voltage = 600V
MPPT Operating Range = 180-1000V
Number of MPPTs = 2
Number of Strings per MPPT = 1+1
Maximum MPPT Current = 26.8A (assuming double the current of one panel for 2 MPPTs)
Calculation:
Number of Panels per String:
To not exceed the maximum DC input voltage of the inverter, we calculate how many panels can be connected in series:
Maximum number of panels in series = Maximum DC input voltage : VOC
Maximum number of panels in series = 1100V / 40V = 27.5
Since we cannot have half panels, we round down: Maximum number of panels in series = 27
Verification of Maximum Voltage:
Total voltage of a string of 27 panels:
Total voltage = 27 × 40V = 1080V
This is below the inverter's maximum DC input voltage (1100V).
Calculation of String Power:
The powers of the panels in series add up:
Total power of one string = 27 × 435W = 11745W (11.745kW)
Compatibility Verification with Inverter:
The inverter has two MPPTs, so we can split the panels into two strings. The maximum input power for the inverter is 18kW, and the total power on two strings is:
Total panel power = 2 × 11.745kW = 23.49kW
This exceeds the inverter's maximum input power. Therefore, either we reduce the number of panels or redistribute the panels better between MPPTs to not exceed the maximum power.
Optimal Distribution:
To stay within the maximum power limit of 18kW:
Distribute these panels into two strings:
Approximately 20.69 panels per MPPT. Rounding down:
20 panels per MPPT
Final Verification:
Voltage of a string of 20 panels:
20 × 40V = 800V
This falls within the MPPT operating range (180-1000V).
Total power:
20 × 435W = 8700W
For two strings:
2 × 8700W = 17400W (17.4kW)
This is below the maximum input power of 18kW.
Conclusion:
For optimal compatibility:
Each MPPT should have 20 panels.
The voltage of each string is 800V, which is within the MPPT operating range.
The total power is 17.4kW, below the 18kW inverter limit.
Thus, the configuration respects the specifications and safety limits of the inverter.
If you need any further information or specific calculations, feel free to ask!
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