A shore power system and its grid-connected control method

Abstract

The invention relates to a shore power supply system. The shore power supply system comprises a shower power grid, a variable-frequency power source, a grid-connection switch, a generator switch and a ship power generation system. The variable-frequency power source comprises a multi-winding transformer and at least one power source module, the input side of each power source module is connected with a low-voltage side winding of the multi-winding transformer, and the output sides of the power source modules are in cascade connection. Each power source module comprises a rectification unit and an inverter unit, and further comprises a high-speed switch, an absorption resistor and a bypass switch, wherein the high-speed switch is connected with the absorption resistor in series, the series connection part is further connected with a direct current output side of the rectification unit in parallel, and the bypass switch is connected with the output side of the inverter unit in parallel. The invention further comprises a grid-connection control method of the shore power supply system. A reverse-power phenomenon is prevented from occurring to the ship power generation system, the success rate of grid connection is greatly improved, and the system is safe, reliable and low in cost.

Description

technical field [0001] The invention relates to the field of power electronic power conversion, in particular to a shore power system applied to ports and wharfs and a grid-connected control method thereof. Background technique [0002] The shore power system is applied to the shore power access technology, which means that when the ship is in port, the generator on the ship is stopped and the land power supply is used instead. The frequency conversion power supply is the core of the shore power access system. It is responsible for converting the 50HZ AC power on the shore into the 60HZ AC power required by the ship through the AC-DC-AC frequency conversion link. The system detects that the voltage of the shore power system meets the conditions and then closes the grid-connected switch to merge the ship power generation system into the shore power system. At this time, a large impact will be generated, and the impact current will cause grid-connection failure or reverse powe...

AI Technical Summary

Problems solved by technology

The frequency conversion power supply is the core of the shore power access system. It is responsible for converting the 50HZ AC power on the shore into the 60HZ AC power required by the ship through the AC-DC-AC frequency conversion link. The system detects that the voltage of the shore power system meets the conditions and then closes the grid-connected switch to merge the ship power generation system into the shore power system. At this time, a large impact will be generated, and the impact current will cause grid-connection failure or reverse power. Phenomenon, when the reverse power occurs, the power direction of the generator flows from the system side to the motor side, at this time, the active power is absorbed from the system, and the reverse power will adversely affect the motor

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