The solar inverter not only has the function of converting DC to AC, but also has the function of maximizing the performance of the solar array, thus having the function of system failure protection.
In summary, there are automatic operation and shutdown functions, maximum power tracking control operation, anti-single operation function (for grid-connected systems), automatic voltage adjustment function (for grid-connected systems), DC detection functions (for grid-connected systems), DC grounding detection function (for grid-connected systems). Here can briefly introduce the automatic operation and shutdown functions, as well as the maximum power tracking control operation.
1. Automatic operation and shutdown function
After sunrise in the morning, the radiation intensity gradually increases, so the output of the solar array also increases. When the output power required by the inverter is reached, the inverter automatically starts to work. After the inverter enters into operation, it always monitors the output of the photovoltaic cell module.
As long as the output power of the photovoltaic cell module is greater than the output power required by the inverter, the inverter will still operate; even if it is cloudy or rainy, the weather will continue until sunset. The inverter can also be operated. When the output of the photovoltaic cell module becomes smaller and the inverter output is close to 0, the inverter enters the standby state.
2. Maximum power tracking control operation
The output of the photovoltaic cell module changes with the radiation intensity, so the temperature of the photovoltaic cell module itself (chip temperature) also changes. In addition, because the photovoltaic cell module has the characteristic that the voltage decreases with the increase of the current, there is an optimal operating point, which will obtain the maximum power. The radiation intensity is changing, so the optimal operating point is also changing.
Relative to these changes, the operating point of the photovoltaic cell module is usually at the extreme point, so the system always obtains the maximum power output from the photovoltaic cell module. This type of control is the maximum power tracking control. The most important feature of the inverter used in the solar power generation system is that it includes an extreme point tracking (MPPT) function.
