CN201174592Y - Active filter for power source - Google Patents

Abstract

The utility model discloses a power supply active filter, which is arranged on a non-linear electronic device for blocking low frequency transduction and high frequency radiation disturbance of the device to a local power supply network. The filter consists of a wave detecting circuit, a resolution circuit, a calculating circuit, a compensation circuit, and a rectifying power supply. The detecting circuit is connected with the local power supply network. An output of the network is connected with the resolution circuit. A fundamental frequency output of the resolution circuit is orderly connected a lower harmonic filtration circuit and a higher harmonic filtration circuit. An output of the higher harmonic filtration circuit is connected with a power consuming device. A harmonic output of the resolution circuit is connected with the calculating circuit. A compensation component parameter outputted by the calculating circuit is connected to the compensation circuit. A compensation component outputted by the compensation circuit is connected to an input end of the detecting circuit. The filter assembly adopts the principle that the wave filtration is primary and the wave compensation is appropriate. The filter has the characteristics of simple circuit structure and small product volume. Furthermore, the filter has the characteristics that the waveform variation of the power supply is tracked and compensated in time, the harmonic component produced by the non-linear device is blocked, and the low frequency transduction and the high frequency radiation disturbance of the power consuming device to the local power supply network are resisted.

Description

The power supply active filter

Technical field

The utility model belongs to filter, particularly relates to a kind ofly being disposed at non-linear electronic equipment and being used to block its power supply active filter to local electric power network low frequency conduction and high frequency radiation interference.

Background technology

It is ubiquitous reality that the harmonic component that non-linear electronic equipment produced is disturbed other power consumption equipment of same electric power network by electric power network, particularly will have a strong impact on the quality of electric power network during each interference source harmonic component generation resonance.Usually adopt power APF for eliminating this harmful interference,, give reactive power compensation simultaneously in order to the harmonic component of filter out power network.

But, not being provided with as yet at locally supplied power source's network under the situation of power APF, its better quality will be difficult to be kept.For this reason, eliminate as far as possible or reduce low frequency conduction that non-linear electronic equipment produces and high frequency radiation the interference of local electric power network is seemed extremely important.

In the prior art; the utility model of patent No. 200620061343.X " active filter " disclose a kind of have eliminate or reduce the technical scheme that non-linear electronic equipment disturbs local electric power network: comprise master control borad (1), tracking plate (2), drive plate (3), unsteady flow module (4) and auxiliary circuit (5), described auxiliary circuit (5) comprises current sample part, Switching Power Supply part, relaying protection part, system hardware protection part and is connected inductor on the electrical network.This utility model is by detecting harmonic wave and the idle component in the load current in real time, the control current transformer, to inject electric power system with harmonic wave and idle component equal and opposite in direction, electric current that direction is opposite, realize the filtering harmonic wave, dynamic compensation is idle, suppress resonance, improve functions such as power factor.Above-mentioned utility model is according to harmonic wave in the load current and idle component, mainly to be the power factor of the technological means raising electrical network of dynamic compensation.Therefore, its circuit structure must adapt to the characteristics of high-power compensation and complicated, and to making small product size bigger.

Summary of the invention

The utility model is that above-mentioned in order to solve " active filter " adapts to high-power compensation and circuit structure is complicated, volume is bigger technical problem, and provide a kind of volume little, can satisfy elimination or reduce the power supply active filter of non-linear electronic equipment local electric power network interference.

The utility model is taked following technical scheme for achieving the above object: this power supply active filter is by the voltage waveform testing circuit, the single-chip microcomputer of embedded software is the counting circuit that main special chip constitutes, compensating circuit and inner rectifier power source are formed, it is characterized in that: voltage waveform testing circuit input is connected in locally supplied power source's network, its output connects fundamental frequency, the harmonic wave decomposition circuit, its fundamental frequency output of described decomposition circuit connects low-order harmonic filtering circuit and high order harmonic component filtering circuit successively, high order harmonic component filtering circuit output connects power consumption equipment, its harmonic wave output of described decomposition circuit is connected in the counting circuit input, the compensate component parameter of counting circuit output is connected in compensating circuit, and the compensate component of described compensating circuit output is connected in voltage waveform testing circuit input.

The utility model can also be taked following technical measures:

Described inner rectifier power source output is connected in counting circuit and compensating circuit power end.

Each composition of described power supply active filter is packaged in a metal shell, housing one end is provided with the binding post and the housing binding post that is connected locally supplied power source's network PE end that connects the network L of locally supplied power source, N end, and the housing other end is provided with binding post that connects power consumption equipment L, N end and the housing binding post that is connected power consumption equipment PE end.

Described low-order harmonic filtering circuit maximum attenuation is o'clock corresponding to 5 subharmonic, and attenuation is at least 8db.

The logical scope of described high order harmonic component filtering circuit band is 15KHz-4MHz.

The beneficial effects of the utility model and advantage are: this power supply active filter composition has adopted the principle that is filtered into main adequate compensation, therefore it is comparatively simple to embody circuit structure, the characteristics that small product size is small, can not only realize the active and passive filtering function of ampere level electric current and high voltage (220V), also has timely tracking, the offset supply wave form varies, the harmonic component that the blocking-up non-linear equipment produces, the opposing power consumption equipment disturbs the low frequency conduction and the high frequency radiation of local electric power network, can obviously improve the electric power network quality, eliminate the pollution of nonlinear load its generation.It is small to the utlity model has small product size, is specially adapted to the little outstanding advantage of same locally supplied power source's network others electric equipment requirement network noise.

Description of drawings

Fig. 1 is an embodiment contour structures schematic diagram.

Fig. 2 is that Figure 1A is to view.

Fig. 3 is an embodiment electricity theory diagram.

Fig. 4 is Fig. 1 embodiment harmonic attenuation performance diagram;

Number in the figure: 1 metal shell, 2 binding posts, 3 housing binding posts, 4 voltage waveform testing circuits, 5 compensating circuits, 6 counting circuits, 7 inner rectifier power sources, 8 fundamental frequencies, harmonic wave decomposition circuit, 9 low-order harmonic filtering circuits, 10 high order harmonic component filtering circuits.

Embodiment

Below in conjunction with embodiment and accompanying drawing thereof the utility model is described in further detail.

Embodiment as shown in Figure 1, 2, each of power supply active filter formed and is packaged in stainless steel metal housing 1, and each composition in shell dimension (the wide * height of the long *) 150*70*50 (mm), metal shell can adopt the epoxy can.The housing left end is provided with the binding post 2 and the housing binding post 3 that is connected locally supplied power source's network PE end that connects the network L of locally supplied power source, N end, and the housing right-hand member is the binding post and the housing binding post that is connected power consumption equipment PE end that connects power consumption equipment L, N end.

As shown in Figure 3, it is the L1 end that the input of voltage waveform testing circuit 4 is connected in locally supplied power source's network, its output connects fundamental frequency, harmonic wave decomposition circuit 8, its fundamental frequency output connects low-order harmonic filtering circuit 9 and high order harmonic component filtering circuit 10 successively, and it is the L2 end that high order harmonic component filtering circuit 10 outputs connect power consumption equipment.The harmonic wave output of decomposition circuit is connected in counting circuit 6 inputs, and the compensate component parameter of counting circuit 6 outputs is connected in compensating circuit 5.The compensate component of compensating circuit 5 outputs is connected in voltage waveform testing circuit 4 inputs.Inner rectifier power source 7 input voltages are taken from the network L1 of locally supplied power source end, and output is connected in counting circuit 6 and compensating circuit 5 power ends.Decomposition circuit 8 in Fig. 3 dotted line, counting circuit 6 and compensating circuit 5 are made of chip UC3854.

Arrow is represented the flow direction of main power source in Fig. 3 electricity theory diagram, and the interference signal that power consumption equipment produces flows to opposite with it, so Fig. 3 circuit bank is paired in main power source and interference signal has dual-use function, specifically:

Voltage waveform testing circuit 4, the voltage waveform that power consumption equipment is fed back to its input detects, and according to the waveform of the one-period that collects, detects remaining low-order harmonic component, uses for counting circuit.

Compensating circuit 5 comes the control compensation circuit with the compensate component that counting circuit calculates, thereby makes the voltage that feeds back to input for sinusoidal wave.Because compensating circuit only compensates the interference signal that this power consumption equipment produces, so the selection of power-type device helps reducing the volume of this device.

Counting circuit 6, the waveform of the one-period that voltage waveform testing circuit 4 is collected calculates, and obtains the compensate component parameters such as harmonic number that this waveform comprises, and uses for compensating circuit.

Decomposition circuit 8: the interference signal of fundamental frequency and power consumption equipment generation is decomposed.

Low-order harmonic filtering circuit 9 is made of the low-order harmonic component that is used for the generation of filtering power consumption equipment inductance and electric capacity.

High order harmonic component filtering circuit 10 is made of the higher harmonic components that is used for the generation of filtering power consumption equipment inductance and electric capacity.

This design of Active Filters considers that mainly the waveform of the power supply that locally supplied power source's network such as generating set send is sinusoidal wave, but load is non-linear, and the current waveform of these loads no longer and the consistent and generation distortion phenomenon of normal electrical network waveform.Therefore this active filter is installed, to guarantee the non-linear no longer locally supplied power source network of power consumption equipment between locally supplied power source's network and power consumption equipment.

Harmonic wave (Harmonic) promptly carries out Fourier series to periodic variable quantity and decomposes, and obtains the component of frequency greater than 1 integral multiple fundamental frequency, and it is produced by locally supplied power source's network nonlinear-load, and concrete computing formula is as follows:

$\mathrm{THD}=\frac{\sqrt{\underset{K=2}{\mathrm{\&Sigma;}}{C}_K^2}}{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="Y20082007403600071.png"\; state="\{\{state\}\}">C</figure-callout>}1}\%$

In the formula: THD is whole harmonic distortions, and C1 is a first-harmonic, and CK is the each harmonic component.

Test is learnt, be applied to the present embodiment of locally supplied power source's network, the harmonic component that its Harmonic Interference is outstanding is 5,7,11,13 subharmonic, amplitude is 2-15dB, and radio frequency interference mainly concentrates in the 15KHz-4MHz scope, so this active filter is considered this two-part interference of filtering simultaneously, the main filtering low-order harmonic of low-order harmonic filtering circuit wherein, and the attenuation points of maximum is placed on 5 subharmonic, and attenuation is at least 8db, and attenuation characteristic as shown in Figure 4.The radio frequency interference of the main filtering 15KHz-4MHz of high order harmonic component filtering circuit is considered the volume of active filter, and it is the principle of main adequate compensation that this active filter is taked with filtering, does not therefore establish compensating circuit for radio frequency interference.

Claims (5)

1, the power supply active filter, by the voltage waveform testing circuit, the single-chip microcomputer of embedded software is the counting circuit that main special chip constitutes, compensating circuit and inner rectifier power source are formed, it is characterized in that: voltage waveform testing circuit input is connected in locally supplied power source's network, its output connects fundamental frequency, the harmonic wave decomposition circuit, its fundamental frequency output of described decomposition circuit connects low-order harmonic filtering circuit and high order harmonic component filtering circuit successively, high order harmonic component filtering circuit output connects power consumption equipment, its harmonic wave output of described decomposition circuit is connected in the counting circuit input, the compensate component parameter of counting circuit output is connected in compensating circuit, and the compensate component of described compensating circuit output is connected in voltage waveform testing circuit input.

2, power supply active filter according to claim 1 is characterized in that: described inner rectifier power source output is connected in counting circuit and compensating circuit power end.

3, power supply active filter according to claim 1, it is characterized in that: each composition of described power supply active filter is packaged in a metal shell, housing one end is provided with binding post that connects the network L of locally supplied power source, N end and the housing binding post that is connected electric power network PE end, and the housing other end is provided with binding post that connects power consumption equipment L, N end and the housing binding post that is connected power consumption equipment PE end.

4, power supply active filter according to claim 1 is characterized in that: described low-order harmonic filtering circuit maximum attenuation is o'clock corresponding to 5 subharmonic, and attenuation is at least 8db.

5, power supply active filter according to claim 1 is characterized in that: the logical scope of described high order harmonic component filtering circuit band is 15KHz-4MHz.

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