A phase-splitting control method and system for a three-phase four-wire parallel three-level SVG

Abstract

The invention discloses a three-phase four-wire parallel three-level SVG phase split control method and system. The three-phase input voltage, three-phase inductor current, DC positive busbar voltage, DC negative busbar voltage and compensation system of the SVG are collected in real time. The phase angle of each phase input voltage is determined according to the three-phase input voltage; the instantaneous value of the reactive current of each phase is obtained according to the phase angle of each phase and the compensation side current, and the instantaneous value of the reactive current of each phase is obtained according to the DC positive bus voltage and DC The negative busbar voltage can obtain the command value of the inductance running current of each phase required under the normal operation of the SVG; add the instantaneous value of the reactive current of each phase and the command value of the inductance running current to obtain the three-phase inductance current command value, and According to the three-phase inductor current command value and the three-phase inductor current acquisition value, the driving signal of the self-commutation bridge circuit of the SVG is adjusted so that the three-phase inductor current acquisition value tracks the three-phase inductor current command value. This application is suitable for unbalanced three-phase loads.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a phase-splitting control method and system of a three-phase four-wire parallel three-level SVG. Background technique [0002] With the development of power electronics and semiconductor technology, more and more power electronic devices appear in the power grid, such as SVG (Static Var Generator, static var generator). As a reactive power compensation device, SVG can compensate the power of the system Reactive power, improve the power factor of the system. At present, SVG is divided into two-level SVG and three-level SVG. Compared with two-level SVG, three-level SVG has smaller volume, lighter weight, small harmonics, and higher power density, so three-level SVG SVG has gradually been widely used; often, three-level SVG will be connected to LCL filter circuit at the input end, on the one hand, it can resist the interference of grid harmonics, on the other hand, it can...

AI Technical Summary

Problems solved by technology

In the prior art, three-phase four-wire parallel three-level SVG is very commonly used, please refer to figure 1 , figure 1 It is a compensation system based on three-phase four-wire parallel three-level SVG in the prior art. The control method it adopts is based on the instantaneous reactive power theory, and extracts the compensation side (that is, the load side) through three-phase coordinate transformation. Reactive power, this control method is three-phase joint control, which is more suitable for three-phase load balance loads, and can achieve balanced control, but for unbalanced three-phase load loads, each phase affects each other, resulting in poor control effect

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