Phase-locked loop control method and system based on dynamic voltage restorer

Abstract

The invention discloses a phase-locked loop control method and system based on a dynamic voltage restorer, and the method comprises the steps the fundamental positive sequence phase of a voltage signal of a three-phase power grid in real time is monitored through a software phase-locked loop; the voltage signals of the three-phase power grid are converted to be based on rotating coordinates through rotating coordinate conversion, positive sequence voltage VS + 1 of the dq voltage signals is obtained, and the positive sequence voltage VS + 1 comprises a D-axis positive sequence voltage component Vsd + and a Q-axis positive sequence voltage component Vsq + 1; and a voltage change threshold Vol _ d _ Min is set, when the amplitude of the D-axis positive sequence voltage passes through the low-pass filter is greater than Vol _ d _ Min, the input quantity of a phase-locked loop controller is defined as Vsq+1Vsd+_Lpf, and when the the amplitude of the D-axis positive sequence voltage passesthrough the low-pass filter is lower than Vol _ d _ Min, the input quantity is defined as vsq+ 1Vol _ d _ Min. The phase-locked loop control method of the dynamic voltage restorer is not influenced bythe change of the amplitude component of the positive sequence voltage any more, and the problem of dynamic response when the traditional phase-locked loop is subjected to the mains supply drop faultis solved. Therefore, both the steady-state characteristic and the good dynamic characteristic can be taken into consideration.

Description

technical field [0001] The invention relates to the field of automatic control, in particular to a dynamic voltage restorer-based phase-locked loop control method and system. Background technique [0002] Dynamic voltage restorer or DVR (hereinafter referred to as DVR), is a series or parallel compensation device with energy storage device (system), which has the ability to compensate active power in addition to reactive power. The application of modern power electronics technology can realize the control of power quality and provide users with specific power supply. [0003] The voltage of the computer system is disturbed and the short-term drop of the voltage on the load side (several cycles to dozens of cycles) is the main reason for the failure of sensitive loads and computer equipment. The dynamic voltage restorer (DVR) generates a compensation voltage within 1-2 milliseconds to offset the interference of the system voltage, so that the voltage on the load side does no...

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Problems solved by technology

[0008] Based on this, it is necessary to provide a lock based on a dynamic voltage restorer that avoids power grid voltage sags in response to the above-mentioned reduction in the positive sequence voltage amplitude, resulting in a smaller control bandwidth of the phase-locked loop, which in turn leads to a grid voltage drop. phase loop control system

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