A power electronic converter capable of clearing bidirectional fault current and its control method

Abstract

The invention provides a power electronic current converter and a control method capable of eliminating two-way fault current. The current converter comprises current conversion bridge arms connected through electric reactors. The current conversion bridge arms comprise T-shaped power submodules connected in series. The two horizontal ends of one T-shaped power submodule are connected through a capacitor and then connected with the vertical end of another T-shaped power submodule. The current conversion bridge arms are sequentially connected through the vertical ends, the electric reactors and the horizontal ends. Submodule controllers and optical fiber current mutual inductors of the current conversion bridge arms are connected with current conversion bridge arm controllers through optical fibers. The current conversion bridge arm controllers are connected with a current converter master controller. According to the control method, dual fault current protection is carried out on the power electronic current converter through a current detection method for a driving circuit and the current conversion bridge arms of a fully-controlled device. Compared with the prior art, the power electronic current converter and the control method capable of eliminating the two-way fault current can rapidly and effectively eliminate the two-way fault current.

Description

technical field [0001] The invention relates to a power electronic converter and a control method, in particular to a power electronic converter capable of clearing bidirectional fault current and a control method. Background technique [0002] Flexible DC transmission technology and flexible AC transmission technology are playing an increasingly important role in the construction of smart grids and new energy power generation; since short-circuit faults are the most serious abnormal conditions in power systems, ensuring flexible DC transmission and flexible AC transmission For normal operation, it is necessary to clear the short-circuit fault through the power electronic converter; based on the division of principles, the converter converter handles the short-circuit fault current including: [0003] ①: Use other equipment on the AC and DC side of the converter (such as AC and DC circuit breakers) to isolate the fault point; [0004] Among them, the DC circuit breaker has ...

AI Technical Summary

Problems solved by technology

[0007] When a short-circuit fault occurs on the DC side of the converter, the full-bridge sub-module (same as the two-level converter) can cut off the current in both directions by blocking, but it requires double the number of semiconductor devices, and the investment is too large; the half-bridge Type sub-module, because the diode connected in anti-parallel with the IGBT device will constitute an energy feed circuit that is directly connected to the AC system at the fault point and cannot be controlled, so it does not have the DC current blocking capability; the clamping twin sub-module adopts a semiconductor device Although the sub-module structure is less than that of the full-bridge type, due to the characteristics of its own topological structure, the capacitance of the clamped twin-sub-module will be charged repeatedly after the system is locked, and the time required to cut off the short-circuit current is longer than that of the full-bridge type. The fault current control effect not ideal

[0008] Therefore, due to the inability to effectively limit the short-circuit current, the existing high-power power electronic converters based on full-control devices are prone to over-current blocking or tripping when the system fails, which seriously reduces the availability of the device and the safety of the power system. stable level

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