A phase-locked loop control method and system based on a dynamic voltage restorer

Abstract

The invention discloses a phase-locked loop control method and system based on a dynamic voltage restorer, wherein the method includes: monitoring the fundamental positive-sequence phase of the voltage signal of a three-phase grid in real time through a software phase-locked loop; The voltage signal of the phase grid is converted to the coordinate based on the rotation, and the positive sequence voltage V of the dq voltage signal is obtained S +1 , where the positive sequence voltage component V S +1 Including the positive sequence voltage component V of the D axis sd + , and the Q-axis positive sequence voltage component V sq +1 ;Set voltage change threshold V ol_d_Min , when the D-axis positive sequence voltage amplitude passes through the low-pass filter, the value is greater than V ol_d_Min , the input quantity of the phase-locked loop controller is defined as when the value of the D-axis positive sequence voltage amplitude passing through the low-pass filter is less than the voltage change threshold V ol_d_Min , the V sq +1 / V ol_d_Min , the phase-locked loop control method of the above-mentioned dynamic voltage restorer is no longer affected by the change of the positive sequence voltage amplitude component, and solves the dynamic response problem of the traditional phase-locked loop when the mains power drops. It can not only take into account the steady state characteristics but also have good dynamic characteristics.

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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