Difference between on grid inverter and off grid inverter.

The on-grid inverter sends energy directly to the grid, so it need to track the frequency and phase of the grid, which is equivalent to a current source. The off-grid inverter is equivalent to establishing an independent small power grid, mainly controlling its own voltage, which is a voltage source. The on grid inverter does not need energy storage, but the energy cannot be regulated, and the photovoltaic generation will send as much as it is sent to the network, regardless of whether people want it or not, the power grid does not like it. Off-grid generally requires energy storage, does not send energy to the network, and the power grid has no right to interfere. The off-grid inverter can work independently after leaving the grid, which is equivalent to an independent small power grid, mainly controlling its own voltage, which is a voltage source.