Interconnection power converter and power generation apparatus using the same

A controlling method of a power converter which converts direct current power to alternate current power, supplies the alternate current power to a power system, and comprises a converter for boosting a voltage of direct current power supplied from a direct current power supply having a ground capacitor, an inverter for converting the direct current power supplied from said converter into alternate current power, wherein an input and output of said inverter are not insulated, a switch which is connected to an output terminal of said inverter and opens/closes an output of said power converter by a mechanical contact, and a detector for detecting a ground fault within a shorter time than an operation time of a customer's ground fault interrupter interposed between said power converter and a power system having one grounded line, said method comprising the steps of:

• changing said switch to an open state when said detector detects a ground fault;
• blocking a gate of said inverter;
• and
• holding an output voltage of said converter to be higher than a peak value of an alternate current voltage of the power system until at least said switch changes to the open state.

A power generation apparatus for supplying alternate current power to a power system and comprising a direct current power supply having a ground capacitor, and a power converter for converting direct current power into alternate current power,

• wherein said power converter comprises:
• a converter for boosting a voltage of direct current power supplied from the direct current power supply;
• an inverter for converting the direct current power supplied from said converter into alternate current power, wherein an input and output of said inverter are not insulated;
• a switch which is connected to an output terminal of said inverter and opens/closes an output of said power converter by a mechanical contact;
• a detector for detecting a ground fault within a shorter time than an operation time of a customer's ground fault interrupter interposed between said power converter and a power system having one grounded line;
• and
• a controller for controlling operations of said converter, said inverter, and said switch, wherein when said detector detects a ground fault, said controller changes said switch to an open state, blocks a gate of said inverter, and holds an output voltage of said converter to be higher than a peak value of an alternate current voltage of the power system until at least said switch changes to the open state.