The following string design formula is proposed with reference to the "Design Specifications for Photovoltaic Power Stations (GB 50797-2012)", which meets two conditions at the same time:

1. The maximum open-circuit voltage of the PV modules after series connection is lower than the maximum access voltage of the inverter;
2. The MPPT voltage of the PV modules after series connection is within the MPPT voltage range of the inverter.
3. Formula (1) Parameter meaning: Vdcmax: maximum input voltage of the inverter; the denominator parameter has been introduced above. Formula (2) Parameter meaning: Vmpptmin: minimum MPPT input voltage of the inverter; Vmpptmax: maximum MPPT input voltage of the inverter; t′: maximum high temperature at the installation location of the component; t: maximum low temperature at the installation location of the component; Vpm: peak power voltage of the component; Kv′: temperature coefficient of peak power voltage of the component (generally calculated using the open circuit voltage temperature coefficient Kv).