Direct voltage control method of dual-end flexible direct current occasion and direct voltage controller

Abstract

The present invention provides a direct voltage control method of a dual-end flexible direct current occasion and a direct voltage controller. The method comprises the steps of: obtaining voltage deviation between a direct voltage reference value of a sending terminal and a direct voltage measurement value of the sending terminal and power deviation between a power reference value of the sending terminal and a power measurement value of the sending terminal; calculating a weighing coefficient according to the voltage deviation and a preset voltage deviation coefficient; performing correction of the voltage deviation according to a preset direct voltage deviation value, and calculating errors according to the weighing coefficient, the corrected voltage deviation and the power deviation through a preset first formula; inputting the errors into a PI controller to obtain a d-axis current, wherein the preset first formula is that: [delta]=K[Delta]u'+(1-K)[Delta]p, [Delta]u' is voltage deviation after correction, [Delta]p is the power deviation, and K is the weighing coefficient. The direct voltage control method of the dual-end flexible direct current occasion and the direct voltage controller perform mode switching (namely calculation equation of errors) through a mathematical function, and the mode switching is set prior to the PI link so as to greatly shorten the time of mode switching and reduce the out-of-limit level of the direct voltage during the faults.

Description

technical field [0001] The invention relates to the field of multi-terminal flexible DC voltage margin control, in particular to a DC voltage stabilization method and a DC voltage stabilizer. Background technique [0002] With the continuous improvement of the penetration rate of flexible DC power transmission, when the AC grid fails, the flexible DC power transmission based on MMC should take advantage of its flexible control, try to maintain continuous operation without disconnecting the grid, and provide support for the recovery of the grid, that is, Fault ride-through capability. The fault ride-through technology is directly related to the reliability and safety performance of the flexible DC transmission system. At present, most of the existing fault control methods focus on single-ended converter station fault control. This is mainly based on the reliable communication between the rectifier station and the inverter station. Ensure the stability of the DC voltage of t...

AI Technical Summary

Problems solved by technology

[0011] The embodiment of the present invention provides a DC voltage control method and a DC voltage controller for a double-terminal flexible DC application, which solves the problem that when the voltage exceeds the system design limit, the controller does not immediately switch the control system to stabilize the DC voltage, resulting in DC The technical problem of excessive voltage overshoot of the system voltage

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