High-capacity tandem type active electric power filter

Abstract

The present invention discloses a large-capacity serial type active power filter which includes fundamental current detection unit I, fundamental compensation current generating unit II and serial transformer III, among which the unit II consists of N (Níœ500) number of the same subunits II' with its input end being connected with output end of unit I, the serial transformer III has N number of the same windings at its secondary side with each winding being connected with the corresponding subunit II' and primary winding being connected in series with electric grid bus. Each subunit II' sendsgenerated fundamental current i2 / N to the corresponding secondary winding ax in the serial transformer according to the fundamental current signal i.s. All i2 / N have the same magnitude and the same phase but antiphase at fundamental curvent i1 of the electric grid bus so as to make fundamental magnetomotive force of the primary.

Description

technical field [0001] The invention belongs to the technical field of power filters, and in particular relates to a large-capacity serial active power filter. Background technique [0002] So far, there are three main types of active power filters: the first type is a parallel active filter; the second type is an active filter and a passive filter connected in parallel with the power grid; source plus series active hybrid filter. Both the first and second types of filters need to detect harmonic currents in real time and follow up to generate harmonic currents, which is difficult to implement. In 1999, the present inventor invented a series active filter based on magnetic flux compensation (see ZL99120103.5, application date December 4, 1999), which belongs to the third type of filter mentioned above. Theoretical analysis and experimental research with various harmonic sources show that when the fundamental wave current injected in the secondary side of the series transfo...

AI Technical Summary

Problems solved by technology

If the required primary side current is large, the secondary side current will also be large. Due to the limitation of the capacity of the existing switching devices, it is impossible to manufacture a large-capacity active filter.

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