Photovoltaic inverter as an important part of photovoltaic power generation, the main role is to convert the direct current emitted by photovoltaic modules into alternating current. The inverter not only has the function of direct AC conversion, but also has the function of maximizing the performance of the solar cell and the function of system fault protection.

The output of the solar cell module varies with the intensity of solar radiation and the temperature of the solar cell module itself (chip temperature). In addition, the solar cell module has the characteristic of voltage decreasing with the increase of current, so there is an optimal operating point to obtain the maximum power. The intensity of solar radiation varies, and obviously so does the optimal working point. Relative to these changes, the operating point of the solar cell module is always at the maximum power point, and the system always obtains the maximum power output from the solar cell module. This control is the maximum power tracking control. The most important feature of the inverter used in solar power system is to include this function.

After sunrise in the morning, the intensity of solar radiation gradually increases, and the output of solar cells increases accordingly. When the output power required by the inverter is reached, the inverter automatically starts to run. After entering operation, the inverter will monitor the output of the solar cell module from time to time. As long as the output power of the solar cell module is greater than the output power required by the inverter, the inverter will continue to run; Until sunset shutdown, even in rainy weather the inverter can run. When the output of the solar cell module becomes smaller and the output of the inverter is close to 0, the inverter will be in standby state.

In solar power generation system, the efficiency of inverter is an important factor to determine the capacity of solar cell and storage battery.