CN201234137Y - High-pass filter capable of parameter changing - Google Patents

Abstract

The utility model relates to a high-pass filter used for an active power filter. It has an LCL high-pass filter body connected in a T shape by two filter inductors, a filter capacitor and a damping resistor. filter capacitors, and a switch is respectively arranged on a branch of each filter capacitor. The utility model realizes the transformation of the filter parameters of the high-pass filter by changing the capacitance value, and only needs to toggle the switch to realize the transformation, which is especially suitable for on-site debugging, saves time and effort, and at the same time, through the appropriate selection of multiple filter capacitance values , so that it has good adaptability to various grid impedances and achieves a good filtering effect.

Description

The high pass filter of convertible parameter

Technical field

The utility model relates to a kind of high pass filter that is used for Active Power Filter-APF, relates in particular to a kind of high pass filter of convertible parameter.

Background technology

In prior art, in order to reduce the influence of high-frequency current component that high power valve in the Active Power Filter-APF (IGBT) produced in switching process to electrical network, general all between the output of Active Power Filter-APF and electrical network, increase a high pass filter, come the absorbing high-frequency electric current with it.Referring to Fig. 2, described high pass filter be one by filter inductance Ls, Lf, a filter capacitor Cf and the T-shaped LCL high pass filter 2 that connects and composes of resistance R _ f.The filtering parameter of general high pass filter 2 designs according to electric network impedance.But in actual applications, the impedance of each electrical network is also inequality, under different electric network impedance situations, the high pass filter filters effect differs bigger, especially in some cases may cause resonance, like this, not only not reach the effect of filtering high-frequency harmonic electric current, also can amplify, influence the filter effect of Active Power Filter-APF complete machine some frequency band electric current.At present, the high pass filter in the Active Power Filter-APF all designs the resistance value of a certain electrical network of pin, and its component parameters and element are installed and all fixed, and when the bad problem of above-mentioned filter effect occurring, can't adjust at the scene.

The utility model content

The purpose of this utility model is at the problem in the prior art, and a kind of high pass filter of convertible parameter is provided, make its parameter be easy to on-the-spot adjust, time saving and energy saving, thereby avoid the resonance that may occur, reach filter effect preferably.

For achieving the above object, the technical solution of the utility model is as follows:

It has one by two filter inductances, filter capacitor and a T-shaped LCL high pass wave filter body that is connected of damping resistance, its improvement part is: the filter capacitor of one or more different appearance values in parallel on described filter capacitor, and on the branch road of each filter capacitor, be respectively equipped with a switch.

By above-mentioned solution as can be seen, the utility model has been realized the conversion of high pass filter filters parameter by changing capacitance, and only need toggle switch, just can realize conversion, be particularly suitable for field adjustable, time saving and energy saving, simultaneously, by suitably choosing of a plurality of filter capacitor values, make it all have adaptability preferably to various electric network impedance, reach good filter effect.Though this improvement has increased some costs, consider that from debugging combination properties such as convenient and product quality it still is very economical and practical.

Description of drawings

Fig. 1, circuit theory diagrams of the present utility model.

The schematic diagram of Fig. 2, existing high pass filter.

Embodiment

This example is that example describes with filter capacitor in parallel.Referring to Fig. 1, this high pass filter 2 has filter inductance Ls, the Lf of two series connection, it also has filter capacitor Cf1, the Cf2 of two parallel connections, and on the parallel branch of two filter capacitors, be connected in series a K switch 1, K2 respectively, the series connection point of two filter inductances of a parallel end connection of described two filter capacitors, its another parallel connected end and a damping resistance Rf join, and they are the T font and connect and compose LCL high pass wave filter 1.Control the change of this high pass filter 1 parameter by the connecting and disconnecting of K switch 1, K2, if K1 closure, K2 disconnect, then the high pass filter filters capacitance is Cf1; If K1 disconnects, the K2 closure, then the high pass filter filters capacitance is Cf2; If K1, K2 are closed simultaneously, then the high pass filter filters capacitance is Cf1+Cf2.

Claims (1)

1, a kind of high pass filter of convertible filtering parameter, it has one by the T-shaped LCL high pass wave filter body that is connected of two filter inductances (Ls, Lf), a filter capacitor (Cf1) and a damping resistance (Rf), it is characterized in that: go up the filter capacitor (Cf2) of one or more different appearance values in parallel at described filter capacitor (Cf1), and on the branch road of each filter capacitor (Cf1 or Cf2), be respectively equipped with a switch (K1 or K2).

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