Control method of voltage sag generator

Abstract

The invention discloses a control method of a voltage sag generator. The method comprises steps of setting voltage sag time, voltage sag type and voltage phasor reference values of positive, negativeand zero sequences; according to the voltage phasor reference values of positive, negative and zero sequences, obtaining phase voltage reference vectors in the three-phase coordinate system; carryingout rotational coordinate conversion on the phase voltage reference vectors in the three-phase coordinate system so as to obtain voltage reference vectors under a dq coordinate system; carrying out reversed rotational conversion on the reference vectors under the dq coordinate system so as to obtain reference voltage under the three-phase coordinate system; carrying out space vector pulse width modulation on the reference voltage under the three-phase coordinate system so as to generate load side inverter switch tube control signals; and when the voltage sag generator operates with active load, imposing power control on the grid side inverter and when the voltage sag generator operates with passive load, allowing the grid side inverter to work in a rectification state. According to the invention, the voltage sag generator can be controlled to quite comprehensively simulate all types of voltage sags, and a special power grid environment is provided for active electric power electronic devices.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a method for controlling a voltage sag generator. Background technique [0002] Since the 1980s, with the continuous development of information technology and the rapid popularization and development of digital control technology, more and more automation equipment has been applied to modern industrial production and people's life. Numerical control machine tools, network servers, medical equipment and automation A large number of sensitive loads such as production lines are connected to the power system. These precision devices are basically based on microprocessors or computers, so the requirements for power grid power quality are much higher than traditional equipment. In addition, in some traditional industries, such as securities trading centers, subways, papermaking, telecommunications, elevators, and relay protection devices in power systems, they are very sensitive...

AI Technical Summary

Problems solved by technology

However, the current three-phase voltage sag generation methods still have shortcomings in terms of the accuracy of generating voltage sag events and the scope of application of test tests. It cannot fully and accurately reflect the various types of voltage sags that may occur in the three-phase system, especially the generated sag voltage is difficult to satisfy the phase relationship and amplitude relationship between phases and phases inherent in the three-phase fault voltage; (2 ) The energy of existing voltage sag generators can generally only be transferred from the grid to the load in one direction, which is only suitable for the electrical performance test and test of "electrical equipment" connected to the grid, and does not consider active equipment (such as photovoltaic parallel Grid inverters, active filters, static var generators (SVG) and other power quality regulation control equipment) are connected to the grid for electrical performance testing and experimental use requirements, and the energy is transferred from the active equipment to the grid

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