Grid-connected inverter and overvoltage suppression method therefor

An overvoltage suppression method for a grid-connected inverter, comprising:

• determining whether a voltage at an alternating-current port of the grid-connected inverter exceeds a preset threshold;
• controlling, in a case that the voltage at the alternating-current port does not exceed the preset threshold, the grid-connected inverter to operate in a current-source mode when being connected to a power grid;
• in a case that the voltage at the alternating-current port exceeds the preset threshold, controlling the grid-connected inverter to operate in a voltage-source mode when being connected to the power grid, to enable a reactive current or a reactive power outputted from the alternating-current port of the grid-connected inverter to respond within a preset duration;
• and switching, when the reactive current is greater than or equal to a preset reactive current or when the reactive power is greater than or equal to a preset reactive power, the grid-connected inverter from the voltage-source mode to the current-source mode.