Photovoltaic energy systems typically include solar cells or components, charge and discharge control systems (or inverters), and load control. Solar cells are devices that convert solar radiant energy into electrical energy based on the principle of photovoltaic effect. Affected by weather, load and other factors, solar cells are not easy to obtain a stable DC output. Therefore, most solar energy systems need to first store energy through the battery and then supply power to the outside. The main function of the charge and discharge controller is to control the charging and discharging process of the battery in the system to prevent the battery from being damaged due to overcharging or overdischarging. The function of the inverter is to convert the low-voltage direct current output from the battery into the alternating current required by the electric appliance.

The grid-connected power generation method converts the direct current generated by the solar array into an AC power through the inverter, and does not need the battery for energy storage. In comparison, the grid-connected power generation is cheaper and completely pollution-free. The grid-connected inverter used in the grid-connected power generation system has an automatic phase and voltage tracking device, which can very well match the small phase and voltage fluctuations of the power grid, and will not affect the power grid.