As a conversion device for solar power generation, the function of solar inverter plays a key role in the overall power station. The solar inverter converts the direct current generated by the solar module into a sinusoidal waveform current, which is connected to the load or integrated into the power grid. It is the core component of the solar power generation system.
However, the solar inverter is not only a DC-AC conversion function, but also has an active operation and deactivation function, a maximum power tracking MPPT function, and an islanding effect inspection and control function.
Actively activate and deactivate functions. After the sun rises in the early morning, the amount of solar radiation gradually increases, and the output of the solar panel also increases. When the power required by the solar inverter is reached, the inverter will run actively. The inverter will always monitor the output power of the solar panel components. As long as the power of the solar panel components is greater than the power required by the inverter target, the inverter will continue to run until sunset. When the output of the solar panel assembly becomes smaller and the output of the inverter is close to zero, the inverter will automatically enter standby.
Maximum power tracking MPPT function when the light intensity and temperature changes, the solar module input power presents a linear change, the solar module is not a constant voltage source, nor is it a constant current source, its power will shift with the output voltage shift, and there is no direct relationship with the load. Its output current along with the voltage rise is a horizontal line at first, and when it reaches a certain power, it decreases with the voltage rise, and when it reaches the module open circuit voltage, the current decreases to zero.
Inspection and control function of islanding effect under normal power generation, the PV grid-connected power system is connected to the grid and delivers effective power to the grid, however, when the grid loses power, the PV grid-connected power system may still be working and in independent operation with the local load, this situation is called islanding effect. When the islanding effect occurs in the inverter, it will cause great danger to life safety, grid operation, and the inverter itself, so the standard specification of inverter into the grid, PV grid-connected inverter must have the inspection and control function of islanding effect.
