The inverter not only has the function of direct AC conversion, but also has the function of maximizing solar cell performance and the system fault protection function. They are summarized as automatic operation and shutdown function, maximum power tracking control function, anti-independent operation function (for grid-connected system), automatic voltage adjustment function (for grid-connected system), DC detection function (for grid-connected system), and DC ground detection function (for grid-connected system). Here is a brief introduction of the automatic operation and shutdown function and the maximum power tracking control function.
1、Automatic operation and shutdown function
After the sun rises in the morning, the solar radiation intensity gradually increases, and the output of the solar cell also increases. After entering operation, the inverter will monitor the output of the solar cell element at all times. As long as the output power of the solar cell element is greater than the output power required for the inverter to work, the inverter will continue to run until it stops at sunset, and the inverter can also run even on rainy days. When the output of the solar cell element becomes smaller and the inverter output is close to 0, the inverter will form a standby state.
2、Maximum power tracking control function
The output of the solar cell element changes with the intensity of solar radiation and the temperature of the solar cell element itself (chip temperature). In addition, because the solar cell element has the characteristic that the voltage decreases with the increase of current, there is the best working point to obtain the maximum power. Solar radiation intensity is changing, so obviously the optimal operating point is also changing. In relation to these changes, the operating point of the solar cell element is always at the maximum power point, and the system always obtains the maximum power output from the solar cell element, and this control is the maximum power tracking control. The most important feature of inverters for solar power systems is the inclusion of the maximum power point tracking (MPPT) function.
