Novel transformerless series voltage regulator

Abstract

The invention discloses a novel transformerless series voltage regulator, which comprises an AC power grid, a single-phase VIENNA rectifier circuit, a three-level inverter circuit, an output filtering unit, a bypass branch and a load. The single-phase VIENNA rectifier circuit is connected with the AC power grid and consists of a boost inductor operating in Boost mode, a power bridge arm and a DC energy storage unit. The three-level inverter circuit is connected with the DC energy storage unit, and includes two clamping diodes connected to a DC output capacitor side, an IGBT switch tube V1, an IGBT switch tube V2, an IGBT switch tube V3, and an IGBT switch tube V4. The output filtering unit is connected to the output end of the three-level inverter circuit, and includes an inductor Lf2 and a capacitor Cf. The invention solves the problem of harmonic pollution on the rectification side, reduces the number of use of switching devices, has no bridge arm straight-through problem on the rectification side, and reduces the complexity of the system control; and in the inverter side control, eliminates the impact of the load on control performance to some extent and improves the response speed and robustness of the system.

Description

technical field [0001] The invention relates to the field of power quality control, in particular to a novel transformerless series voltage regulator. Background technique [0002] Aiming at the power quality problems such as voltage sag, low voltage and harmonics existing in the power grid, the series active voltage quality regulator is a direct and effective solution to ensure the normal operation of sensitive loads by injecting compensation voltage into the power grid. Conventional direct-mount topologies include Dsyc's uncontrolled half-bridge rectification and two-level half-bridge inverter structure, H-bridge topology, and three-arm topology. Among them, the Dsyc topology has the problem of harmonic pollution on the rectification side. Whether the H-bridge topology is two-level or three-level topology, both the rectifier side and the inverter side are bridge-type topology, there is a problem of direct connection, the number of tubes is large, and the control is compli...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a new type of transformerless series voltage regulator, which solves the problems of harmonic pollution brought by the rectifier side, large number of tubes, complicated control and straight-through, etc., and improves the stability of the system. Dynamic response speed and stability of disturbance

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