On-line self-adaptive harmonic current detection system

Abstract

The invention discloses a testing system for on-line self adaptive harmonic currents, which is characterized in that the system is composed of a signal preprocessing part, a referencing orthogonal signal producing part, a self-adaptive filtering part of computer software, and a computer analyzing and displaying part. The superiorities of the invention lie in that delays and phase shifts which are produced in signals and can't be compensated can be compensated by the system, the dynamic responsing characteristics and the testing accuracy of the testing system are increased, an improved type self-adaptive filtering algorism is presented, which overcomes fixed limitations which are existed in traditional self-adaptive testing methods. active power and reactive power of base waves can be tested out through the system, which is convenient for APF reactive power current compensation, a method for producing referencing voltage through phase-locked loop is adopted, which decreases sampling interference of voltage signals to the lowest level and produces sine wave type referencing voltage, and a method for connecting a low-pass filter in front of an integrator is adopted, which increases the testing accuracy and the dynamic response characteristics of the testing system. The system also applies for testing each component of the voltage.

Description

(1) Technical field: [0001] The invention relates to a fast detection system for harmonic current components, in particular to an online self-adaptive harmonic current detection system, which is used in the technical field of current signal processing. (two) background technology: [0002] At present, the application prospect of active power filter in power system is increasingly promising. The harmonic current detection method it adopts is very important, which determines the detection accuracy and dynamic response characteristics of the harmonic current, and thus directly affects the compensation effect of the harmonic current. Whether it can quickly and accurately detect the harmonic and reactive components in the system is the prerequisite for its successful application. [0003] The detection method based on instantaneous reactive power theory is a very common method. Its detection and compensation effect is relatively obvious, but it can only detect the harmonic compo...

AI Technical Summary

Problems solved by technology

That is, when the voltage is asymmetrically distorted, the detection accuracy is not high or even cannot be detected, and there may be a mutual restrictive relationship between the dynamic response speed and the detection accuracy: if the high detection accuracy of harmonic calculation is to be ensured, the dynamic response speed is very slow; if the dynamic response is improved speed will significantly reduce the detection accuracy

Therefore, it is difficult for this method to achieve the best detection accuracy and dynamic response speed at the same time.

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