Single-phase reactive compensator based on buck-boost AC chopper

Abstract

The invention discloses a single-phase reactive compensator based on a buck-boost AC chopper, which relates to the technical field of power system application. The single-phase reactive compensator can make dynamic compensation for the reactive current of a single-phase grid side. The single-phase reactive compensator based on a buck-boost AC chopper includes an input filter, a buck-boost direct AC-AC conversion unit and a reactive compensation capacitor connected in turn. The input filter and the buck-boost direct AC-AC conversion unit constitute a buck-boost AC chopper. According to the single-phase reactive compensator based on a buck-boost AC chopper, the reactive compensation capacitor adopted is a thin film capacitor, and the whole device is smaller, cheaper and more reliable and iseasy to manufacture in a modular way. Through pulse width modulation on a switch tube, the reactive compensation current adjustment range of the whole device is wider under the condition that the voltages of the reactive compensation capacitor and the single-phase grid are the same.

Description

technical field [0001] The invention belongs to the technical field of power system application, and in particular relates to a single-phase reactive power compensator based on a buck-boost AC chopper. Background technique [0002] With the rapid development of the economy, reactive power has become an important physical quantity in the power system. Most network components and loads need to consume reactive power. It is obviously unreasonable for these reactive power to be provided by generators and to achieve long-distance transmission. It is even impossible, and the reasonable method is to set up reactive power compensation devices where reactive power needs to be consumed, and absorb (or send out) reactive power to the grid. [0003] The early reactive power compensation devices include synchronous condensers, shunt capacitors, etc., which have many disadvantages such as large size, high cost, and limited dynamic compensation. Therefore, static var compensation devices ...

AI Technical Summary

Problems solved by technology

The DC side of the voltage source inverter uses a large-capacity electrolytic capacitor bank as an energy storage element. The use of electrolytic capacitors brings the following problems: First, the electrolytic capacitor has a short life and is easily damaged, which makes the STATCOM device less reliable; second, Energy storage capacitors are bulky and expensive, which greatly limits the market prospects of STATCOM

The current research on new reactive power compensators is based on step-down AC choppers and step-up AC choppers. When the grid voltage level and reactive power compensation capacitors are determined, the reactive power compensation current regulation provided by them is The range is small, and it is not suitable for grid nodes with a large range of reactive power changes. Therefore, this technology is in the development stage. The introduction of new AC choppers and the expansion of the reactive power compensation current adjustment range need to be further studied.

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