High-voltage direct-hanging type scalable vector graphics (SVG) comprehensive control device and comprehensive control method

Abstract

The invention discloses a high-voltage direct-hanging type scalable vector graphics (SVG) comprehensive control device and an SVG comprehensive control method. The comprehensive control device is connected with an electric network. Each phase of the high-voltage direct-hanging type SVG comprehensive control device comprises an inductor-capacitor (LC) filter branch, a connection reactor and an H-bridge unit serial branch, wherein the H-bridge unit serial branch is connected in series with the connection reactor and then connected in parallel with the LC filter branch; the LC filter branch comprises an inductor and a capacitor; the H-bridge unit serial branch comprises N H-bridge units which are connected in series; N is more than or equal to 2; and each H-bridge unit comprises a bridge circuit which consists of four power elements. The comprehensive control method comprises a step of comprehensive control; and the step of comprehensive control further comprises a detection step, in which a detection method based on a plurality of synchronous rotational coordinates is adopted so as to carry out comprehensive control on a reactive current, a negative-sequence current and a harmonic current. The technical scheme of the invention has the advantages of simple structure, high response speed, good waveform of an output voltage, flexible control, convenience for modular manufacturing, and the like.

Description

technical field [0001] The invention relates to an electric energy comprehensive control device and a method thereof, in particular to an H-bridge-based cascaded high-voltage direct-mounted SVG comprehensive control device and a method thereof, which are widely used in various power systems. Background technique [0002] In recent years, under the impetus of the national energy saving policy, the electrical energy saving of large industrial and mining enterprises has become a research hotspot, and reactive power and harmonic compensation are the main ways to achieve electrical energy saving. On the one hand, power loads are becoming more and more complex and diverse. Especially in order to save energy and improve the operation effect of the power system, the power supply department encourages users to replace and use faster and more efficient production equipment. For example, various frequency conversion and speed regulation equipment in industrial systems are replacing tra...

AI Technical Summary

Problems solved by technology

[0003] Most of the current electrical equipment is an inductive load. In addition to obtaining useful active power from the power supply, there is also a large amount of reactive power exchanged between the power supply and the load, resulting in a decrease in power factor, resulting in the following adverse effects:

[0004] (1) It causes the line current to increase, so that the capacity of the power supply and distribution equipment cannot be fully utilized, and the power supply capacity of the system is reduced;

[0005] (2) The effective value of the current increases, causing the power loss and power loss of equipment and lines to increase sharply;

[0006] (3) The voltage loss of the line and the transformer is increased, and the change is intensified, which makes the voltage quality of the load terminal decrease;

[0007] (4) For the generator, the increase of reactive current will increase the demagnetization effect of the motor, reduce the terminal voltage, and reduce the output of the generator

Generally speaking, the proportion of the harmonic current is not large compared with the fundamental current, but the harmonic frequency is high, and the skin effect of the wire makes the harmonic resistance increase a lot, so the loss caused by the harmonic is also large

[0011] (2) Harmonics will cause additional losses in rotating electrical machines and transformers

The impact of harmonics on rotating motors and transformers is mainly to cause additional loss and overheating, followed by mechanical vibration and harmonic overvoltage, which will shorten the life of the motor or transformer, and even damage the motor or transformer in severe cases

[0012] (3) Harmonics are very harmful to power equipment

[0016] At present, the compensation equipment has a single function and is mainly biased in one direction, either focusing on reactive power and taking into account some harmonics, or focusing on harmonics and taking into account some reactive power

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