Microgrid system, power converter, and control method for power converter

A power converter, comprising:

• a first output end configured to be connected to a microgrid bus;
• and
• a first input end configured to be connected to a direct current (DC) power supply,
• wherein the power converter is configured to:
• control, when a power grid fails, itself to be in a first current source control mode, wherein the first current source control mode comprises a current source failure ride-through control mode, and wherein the power grid comprises a microgrid system or an external power grid;
• and
• switch, after the power grid failure has occurred for a first duration, the power converter from the first current source control mode to a first voltage source control mode,
• wherein the first voltage source control mode is a voltage source failure ride-through control mode,
• wherein the first duration is less than a second duration, and
• wherein the second duration is a time interval between a first moment at which the power grid fails and a second moment at which a grid-tied switch is turned off.

A method, comprising:

• detecting whether a power grid fails, wherein the power grid comprises a microgrid system or an external power grid;
• controlling, when the power grid fails, a power converter to be in a first current source control mode, wherein the first current source control mode is a current source failure ride-through control mode, and wherein an input end and an output end of the power converter are connected to a direct current power supply and a microgrid bus respectively, and the microgrid bus is connected to an external power grid through a grid-tied switch;
• and
• switching, after the power grid failure has occurred for a first duration, the power converter from the first current source control mode to a first voltage source control mode,
• wherein the first voltage source control mode is a voltage source failure ride-through control mode,
• wherein the first duration is less than a second duration, and
• wherein the second duration is a time interval between a first moment at which the power grid fails and a second moment at which a grid-tied switch is turned off.