A uniform electric energy quality regulator using DC energy-storage to proceed electric isolation

Abstract

The invention relates to a united electric energy quality adjuster that adopts DC storage module, including: current compensator including a first inversion body and a filter composed of inductance; a DC storage module connected in parallel with the DC sides of voltage compensator; a voltage compensator including a second inversion bridge composed of four switch tubes and a filter composed of capacitance and inductance. The regulator both meets the requirement for electrical isolation between power system and the regulator and the energy flowing requirement in the current and voltage compensation control course and simultaneously, can avoid various disadvantages caused by adopting transformer isolation in existing technique.

Description

technical field [0001] The invention relates to a unified power quality conditioner which adopts DC energy storage for electrical isolation, and belongs to the technical field of electric power equipment. Background technique [0002] The power quality conditioner is a device in the power system that eliminates the pollution of the power quality in the system by compensating the distortion components of the voltage and current in the system. According to its working object, it can be divided into two types: voltage-type power quality regulator and current-type power quality regulator. [0003] Unified power quality conditioner (hereinafter referred to as UPQC) is a flexible AC transmission (FACTS) technology, which combines the functions of voltage-type power quality conditioner and current-type power quality conditioner, and can guarantee the voltage quality of the load side at the same time and current quality on the system side. Compared with other FACTS components, it ...

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Problems solved by technology

[0005] (1) When performing voltage and current harmonic compensation, all harmonics generated by the inverter need to pass through the transformer. However, the frequency band of the current power frequency or high frequency transformer is very narrow, and only the current near the rated frequency can be allowed to pass through. , can not meet the requirements of harmonic compensation, greatly affecting the compensation effect

[0006] (2) The high-order harmonics generated by the inverter will cause a large harmonic loss when passing through the transformer, and the passage of high-order harmonics will increase the required capacity of the transformer

[0007] (3) The transformer increases the power loss of the device; reduces the efficiency of the device

[0008] (4) For the series isolation transformer, the interaction with the filtered inductance and capacitance will bring additional phase shift and voltage drop, which will affect the performance of the device for voltage compensation

[0009] In addition, the transformer also has problems such as saturation and inrush current when the voltage drops.

Therefore, the disadvantages of introducing a transformer when the voltage level is low or the capacity of the switching device is sufficient is far greater than the advantages.

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