An AC-DC hybrid microgrid fault ride-through control device and method

Abstract

The invention relates to a fault ride-through control device and method for alternating / direct current mixed microgrid, and belongs to the field of operational control of the alternating / direct current mixed microgrid. A power release unit, a direct current voltage adjusting unit, a direct current power release unit and a central monitoring unit are added to an alternating / direct current mixed microgrid system to form an alternating current fault ride-through coordination control structure of the alternating / direct current mixed microgrid system. By means of the fault ride-through control device and method for the alternating / direct current mixed microgrid, a controllable release access of excess power in a failure process is achieved, tide mutation is prevented from impacting equipment in the grid, voltage fluctuation of a low-voltage direct current bus is stabilized, lockout of alternating / direction current power exchanging equipment is avoided, the alternating / direction current power exchanging equipment is made to transmit power in the failure process, the impact to a power frequency conversion unit from failure current is reduced, tide distribution in the grid is controlled in an optimal mode, the excess power is controlled to be released, overcurrent loss is reduced, normal work in the failure process is guaranteed, and alternating current fault ride-through is achieved when alternating / direct current microgrids are connected. The fault ride-through control device is compact in structure, achieves fault ride-through with the minimum loss method, and has popularization significance.

Description

technical field [0001] The invention belongs to the field of operation control of an AC-DC hybrid microgrid, and in particular relates to an AC-DC hybrid microgrid fault ride-through control device and method. Background technique [0002] For the AC-DC hybrid microgrid system, in order to reduce the impact of the sudden change of the power flow in the AC-DC hybrid microgrid and the failure of the AC microgrid system on the DC microgrid system, and improve the safety and reliability of the power electronic equipment in the network , it is required that when the AC microgrid system has a serious grid voltage drop fault (such as a three-phase short-circuit fault, etc.), the communication bus between the AC and DC microgrid systems should not be disconnected as much as possible, and the disconnection of the communication bus between the AC and DC hybrid microgrid systems should be avoided. The re-connection to the grid after fault recovery will cause a sudden change in the powe...

AI Technical Summary

Problems solved by technology

These technologies have serious limitations, and they have not been able to improve the fault ride-through level of the AC-DC hybrid microgrid and suppress the voltage fluctuation of the DC low-voltage bus.

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