The operating principle of the grid-connected solar system is: when the solar photovoltaic cell components are irradiated by sunlight, electricity will be generated. The inverter converts direct current to alternating current and adjusts the output voltage and frequency to match the grid. The alternating current converted by the inverter can meet the electric energy demand of the user, and inject excess electric energy into the grid. When solar energy is insufficient or unable to meet user needs, the system will obtain the required power from the grid.