Second harmonic-based hybrid active power filter device control strategy

Abstract

The invention discloses a second harmonic-based hybrid active power filter device control strategy. The control strategy particularly comprises the following steps: various different control strategies are analyzed, and a selectable control strategy is decided initially; the system stability and the dynamic performance under the selected control strategy are measured; a control correction link is introduced, and the control strategy is optimized; system impedance frequency characteristics and a current amplification curve are checked; and the filter effects of the system are verified, and the control strategy is determined. Based on the circuit characteristics of the second harmonic-based hybrid active power filter device, the filter performance, the stability and the dynamic performance of the control strategy are discussed. After the control strategy of the invention is adopted, the control correction link order of the control system is greatly reduced, the complexity degree of the controller is simplified, the second harmonic at a power grid side and surrounding inter harmonic current can be effectively restrained, and the stability of the power system is further improved.

Description

technical field [0001] The invention relates to the field of harmonic control, in particular to a control strategy for a hybrid active filter device for suppressing second harmonics and surrounding harmonics. Background technique [0002] With the rapid development of power electronics technology, the load characteristics and operation modes of modern power devices are more complicated. Some nonlinear, impulsive and unbalanced loads, such as large electric arc furnaces, rolling mills, etc., often need to achieve rapid changes in voltage and current. Rapid changes in value and phase, rectifier transformer DC bias and dynamic harmonic coupling of AC and DC networks, etc., usually excite low-order harmonic resonance on the AC side, such as the formation of larger 2nd harmonics and their surrounding harmonics . The national standard GB / T14549-1993 "Power Quality-Public Grid Harmonics" clearly stipulates the 2nd harmonic voltage limit of the public grid and the allowable value ...

AI Technical Summary

Problems solved by technology

The advantage of a passive filter is that it can provide reactive power compensation and suppress a certain harmonic for the system, and it is easy to maintain and operate stably; its disadvantage is that it cannot filter out wide continuous frequency band harmonics, and inevitably causes side lobe amplification

The advantage of the active filter is that it can dynamically suppress harmonics and compensate reactive power, and has a fast response speed, effectively avoiding circuit resonance, etc.; its disadvantage is that it is limited by the voltage and current levels of the current fully-controlled power electronic switch, and the large-capacity active filter High cost and complex control

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