Is the higher the DC string voltage of the inverter the better the power generation?

Does the higher the DC string voltage of the inverter, the better the power generation? Not really. Within the MPPT operating voltage range of the inverter, there is a rated operating voltage value. When the voltage value of the DC string is at or near the rated voltage value of the inverter, that is, within the full load MPPT voltage range, the inverter can output its rated power value.

If the string voltage is too high or too low, the string voltage is far away from the rated voltage value/range set by the inverter, and its output efficiency is greatly reduced. First, the possibility of outputting rated power is excluded – this is not desirable; secondly, if the string voltage is too low, the Boost circuit of the inverter needs to be frequently mobilized to work continuously, and the continuous heating causes the internal fan to work continuously, which ultimately leads to efficiency loss; if the string voltage is too high, it is not safe and limits the I-V output curve of the component, making the current smaller and the power fluctuation larger.

Taking a 1000V-class inverter as an example, its rated operating voltage point is generally 600V, and the full-load MPPT voltage range is between 550V and 850V. If the input voltage exceeds this range, the performance of the inverter will be unsatisfactory.

Inverter parameters:
2 (18)(1)
Typical 182mm silicon wafer size parameters:
3 (18)
Typical 210mm wafer size module parameters:
1 (17)

In actual operation, considering the negative temperature coefficient characteristics of the components, the following recommendations are made for the parameters of the mainstream 182 and 210 modules on the market:
For 182 modules, connect about 16 modules in series, preferably 13 to 17 modules;
For 210 modules, connect about 18 modules in series, preferably 16 to 22 modules.
Of course, the above string recommendations should be determined in combination with specific module parameter values. Currently, various new technologies, new versions, and new specifications of modules are still emerging in the market, and they are changing rapidly; while the parameters of the inverter are relatively stable. When matching, the main focus is on the correspondence between the string voltage and the rated/full-load MPPT voltage range of the inverter, and there will be no mistakes.
Note: 1000V is the voltage protection threshold. If it is reached or exceeded, the system will have irreversible fault errors or safety accidents.

Scroll to Top
Request A Quote Form