Knowledge Point Series 2 for String Inverters
6. If one string of modules is shaded by 2 modules, will it affect the normal power generation of the other string of modules under the same MPPT?
Answer: The MPPT algorithm adjusts the voltage to find the maximum power point. In this case, there will be two power peaks, and the MPPT tracking point will be lower than normal, reducing the power generation efficiency.
7. Can south-facing and north-facing slopes share an inverter?
Answer: They can share an inverter, but modules on different slopes need to be placed in different MPPTs, and the number and orientation of each string of modules under the same MPPT need to be consistent.
8. Can modules with different power ratings be connected in series? Or can they be connected in series when the power difference is not significant? How much power difference can be connected in series?
Answer: It is not recommended to do so because the different power ratings of modules mean different working currents. If they are connected in series, the entire string of modules will follow the current of the smallest module. The greater the power difference, the greater the current difference.
9. What is the difference between maximum short-circuit current and maximum input current?
Answer: The maximum allowable current measured by short-circuiting the positive and negative poles is the maximum short-circuit current, and the maximum working current refers to the maximum output current value allowed for the string of modules.
10. Can the DC input of the inverter be calculated based on the rated voltage of the modules?
Answer: It can be calculated according to the design specifications of the photovoltaic power station. That is, it needs to meet the calculation based on the open-circuit voltage of the modules (the maximum number of modules connected in series for each string), and also needs to meet the calculation based on the working voltage of the modules (according to the MPPT efficiency of the inverter). The specific calculation method can be determined according to the actual situation.