CN106602563A

CN106602563A - Coupled filter

Info

Publication number: CN106602563A
Application number: CN201611166661.7A
Authority: CN
Inventors: 陈旭彬
Original assignee: Shenzhen City West Kaishi Electric Co Ltd
Current assignee: Shenzhen City West Kaishi Electric Co Ltd
Priority date: 2016-12-15
Filing date: 2016-12-15
Publication date: 2017-04-26

Abstract

A coupled filter relates to the field of power electronic technology. A reactor used in a circuit is a filtering reactor and is obtained through combining two reactors L1 and L2 which are required by a traditional circuit. Two induction coils are mounted on an iron core and operate in series for performing excitation on the iron core. A magnetic field is calculated at an aspect of excitation current vector combination, thereby determining a magnetic path parameter. The filtering reactor has relatively small size and small weight, thereby reducing cost and improving circuit efficiency. One filtering reactor and at least one capacitor can form a lowpass gamma-type filter which is a coupled filter. Or the filtering reactor and at least one capacitor form a lowpass T-type filter which is a coupled LCL filter. The self inductance of the two inductors is lower than that of the two inductors of the common filter. On the same current condition, the size is smaller than that of the common filter, and furthermore cost reduction and weight reduction can be realized.

Description

Coupled filter

Technical field

The present invention relates to electric and electronic technical field, and in particular to a kind of coupled filter.

Background technology

In the administering method of harmonic wave, it is a very universal and economic method using passive filtration unit, it passes through The parameter of adjustment capacitor and reactor, the harmonic wave to certain subharmonic (single tuned filter) or certain frequency range (filter by high pass Ripple device, low pass filter) very low-impedance passage is presented, so as to avoid its inflow system.

Harmonic filter installed in the power input of equipment is referred to as device level harmonic filter.Device level harmonic Device has different requirements from bus level harmonic filter.Device level harmonic filter together constitutes with one completely with the equipment matched somebody with somebody System, the effect of harmonic filter is that the harmonic current transmitting for ensureing this system meets specific standard, for example, GB17625 standards, IEEE519 standards.Therefore, device level harmonic filter will meet the requirement of four aspects：Filtering effect Fruit determines, does not absorb upstream harmonic current, be not result in advanced power factor, ill effect does not occur with system.

Device level harmonic filter commonly uses schematic diagram (being analyzed with single-phase), sees Fig. 1 (a), the harmonic wave that L1 is produced to equipment Electric current forms a high resistant, and L2 and C forms a low impedance path to certain harmonic current once, makes the harmonic wave electricity of a certain secondary frequencies The most of series resonant tank for flowing into L2 and C of stream, reduces harmonic current and flows into network system；Other in L1 network systems The harmonic current that equipment is produced also forms a high resistant, and harmonic filter will not absorb the harmonic current of upstream equipment generation.

Parallel branch series resonance frequency fs：

L2- filter inductance inductance values

C- filter capacitor capacitances

Parallel resonance frequency fp：

L1- is input into inductance inductance value

L2- filter inductance inductance values

C- filter capacitor capacitances

In Fig. 1 (a), two inductance L1 and L2 only have electric contact, do not have the contact of magnetic.

Another conventional inversion output or commutation inversion filter circuit are LCL filter circuits, still with list Mutually analyzing, Fig. 1 (b) is seen.

LCL filter resonant frequency fr：

L1- rectification side inductance inductance values

L2- load-side inductance inductance values

C- filter capacitor capacitances

Can be seen that wave filter has two inductance by the analysis of above-mentioned two wave filter commonly used, L1 and L2, if this two Individual inductance makes the reactor of 2 independent reactors or conjugation-type, from cost, volume or weight for not It is highly desirable.

Main reason is that：Two inductance L1, L2 in conventional filter circuit, according to common manufacture method, difference It is two independent reactors, its structure is shown in Fig. 1 (c), or a conjugation reactor group of simple superposition, both essence Identical, difference less, causes linear dimension, volume, weight increase, the defect of cost up.

The content of the invention

It is an object of the invention to provide a kind of inductance of self-inductance of two inductance than two inductance of conventional wave filter Amount is little, less than the wave filter commonly used in same current conditions lower volume, and with reduces cost, can mitigate the coupling of weight Formula wave filter.

In order to solve the problems of background technology, the present invention is to employ the following technical solutions：A kind of manifold type filtering Device, in having three or more than three branch roads and having the filter circuit of common node, the reactor in two or more branch roads Manifold type reactor, and positive connection are made, the components and parts such as electric capacity and resistance composition coupled filter is then mixed, its In, manifold type reactor is because there is a mutual induction amount in two reactors for intercoupling, and they are positive connections, therefore The total inductance amount of reactor is equal to its self-inductance and adds mutual induction amount, so making two reactors of manifold type reactor oneself Sensibility reciprocal can take a little bit smaller.

Reactor in described coupled filter circuit, is that two reactors independent mutually in traditional circuit are closed Two is one, makes a reactor, has been set with two coils for flowing through out of phase exciting curent on every phase stem stem of its iron core, And positive series connection, two coils are mutually coupled, jointly to iron core excitation.

The present invention principle be：The mounting coil of two reactors on same core limb, tandem working, jointly to ferrum Heart excitation and set up magnetic field.Knowable to filter circuit configuration, due to the presence of filter capacitor, encouraging for two reactors is flow through Magnetoelectricity stream is out of phase two vectors, will remove calculating magnetic field from the angle of Vector modulation, determine magnetic circuit parameters；And it is electric two When anti-device is fabricated separately, the magnetic circuit of two is each independently not in contact with, and scalar consideration is pressed in the effect of two exciting currents to magnetic field, In the case of so two kinds, size unshakable in one's determination is necessarily different.

After using above-mentioned technical proposal, the invention has the advantages that：

1st, the iron core of the iron core less than traditional structure of filter reactor is coupled, less iron core produces less loss, disappears The less copper cash of consumption, reduces cost, also reduces size and weight；

2nd, in the manufacture process of reactor, processing unshakable in one's determination and coil winding are requirement highests, link when most taking a lot of work, by Originally process two iron cores and be changed into one, be changed into three from six coils of coiling, greatly reduce workload, this can undoubtedly improve Production efficiency, reduces production cost；

3rd, filter reactor is coupled because circuits improvement occurs, unique structure makes which be respectively provided with application and manufacture link The incomparable superiority of traditional structure, be same type filter reactor manufacture and design new invention, new technique, biography can be substituted System structure, with good development prospect；

4th, the self-inductance of two inductance of coupled filter is less than the inductance value of two inductance of the wave filter commonly used, So under same current conditions the volume of coupled filter can than commonly use wave filter it is little, and can with reduces cost, Mitigate weight；

5th, the conclusion drawn by geometric similarity law, this coupling filter reactor structure for uniting two into one is relative to tradition Structure, its linear dimension, volume, weight necessarily reduce, and cost is reduced.

Description of the drawings

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing Accompanying drawing to be used needed for having technology description is briefly described, it should be apparent that, drawings in the following description are only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with Other accompanying drawings are obtained according to these accompanying drawings.

The harmonic filter schematic diagram that Fig. 1 (a) is commonly used for device level in background technology；

Fig. 1 (b) is LCL filter schematic diagram conventional in background technology；

The structure chart of single reactors of the Fig. 1 (c) to commonly use in background technology；

Fig. 2 is the differentiation schematic diagram of the coupling filter reactor of embodiment provided by the present invention；

Fig. 3 is the manifold type harmonic filter structure chart of embodiment provided by the present invention；

Fig. 3 (a) is device level manifold type harmonic filter schematic diagram in embodiment provided by the present invention；

Fig. 3 (b) is manifold type harmonic filter equivalent schematic diagram in embodiment provided by the present invention；

Fig. 4 is the manifold type LCL filter structure chart of embodiment provided by the present invention；

Fig. 4 (a) is manifold type LCL filter schematic diagram in embodiment provided by the present invention；

Fig. 4 (b) is manifold type LCL filter equivalent schematic diagram in embodiment provided by the present invention；

Fig. 5 is 7.5KW manifold type harmonic filter filter effect figures in embodiment provided by the present invention；

Fig. 6 is 7.5KW manifold type harmonic filter frequency versus impedance curve charts in embodiment provided by the present invention；

Reference：

A- intermediate nodes；B- input nodes；D- output nodes；G- ground；The-the first inductance of L1 '；R1 '-first resistor；L2’- Second inductance；R2 '-second resistance；C- capacitors；F- is loaded；The first reactors of L1-；The second reactors of L2-.

Specific embodiment

In order that the objects, technical solutions and advantages of the present invention become more apparent, below in conjunction with accompanying drawing and it is embodied as Mode, the present invention will be described in further detail.It should be appreciated that specific embodiment described herein is only to explain this Invention, is not intended to limit the present invention.

Fig. 2 is referred to, Fig. 2 is the differentiation schematic diagram for coupling filter reactor；A kind of coupled filter, it is comprising at least One the first reactor L1, at least one second reactor L2, wherein, the first described reactor L1 and the second reactor L2 are Make the coupling filter reactor of drop-over；First reactor L1 and the second reactor L2 unite two into one, and make a reactor, the The coil of one reactor L1 and the second reactor L2 is unshakable in one's determination around, sharing one together, and two coils are mutually coupled, jointly to ferrum Heart excitation.

In this specific embodiment, the theoretical foundation of coupling filter reactor is：

First, geometric similarity law

A series of similar reactor class product of structures, its linear dimension L, volume V, weight G meet with the change of capacity The relation of exponential function.

That is, when capacity rises to P2 by P1,

One is done by similarity law below to compare, two reactors is fabricated separately and is united two into one and makes one, observed The situation of change of L, V, G under two schemes.

Assume that various proportionality coefficients are 1；The capacity phase of two reactors one first reactor L1 and the second reactor L2 Deng P1=P2=1；Its linear dimension, volume, the data of weight are all 1；Unite two into one and make a reactor L3, capacity P3 Front two sums, i.e. P3=P1+P2, by can be calculated following table data.

Scheme	P	L	V	G
					Independent L1	1	1	1	1
Independent L2	1	1	1	1
					Independent two sums	2	2	2	2
Unite two into one L3	2	1.19	1.68	1.68

In observation table, data can be seen that：When making one two, its linear dimension, volume, weight are respectively less than independent Two sums.

2nd, the summation of scalar, vector

According to circuit theory, in circuit scalar and algebraical sum equal to its amplitude；Vector summation is relevant with angle, should be by Vector rule computing, when angle is not zero, the amplitude of vector is less than the algebraical sum of each vector magnitude.

, on same core limb, tandem working is common right for the mounting coil of the first reactor L1 and the second reactor L2 Iron core excitation and set up magnetic field.Knowable to filter circuit configuration, due to the presence of filter capacitor, the first reactor L1 is flow through Exciting current with the second reactor L2 is out of phase two vectors, will remove calculating magnetic field from the angle of Vector modulation, it is determined that Magnetic circuit parameters；And when two reactors are fabricated separately, the magnetic circuit of two is each independently not in contact with, two exciting currents are to magnetic Scalar consideration is pressed in the effect of field, then in the case of two kinds, size unshakable in one's determination is necessarily different.

Column section product Az unshakable in one's determination is significant data unshakable in one's determination, can react substantially size unshakable in one's determination, below by calculating Carry out the Az values of the new and old two kinds of structures of comparison.

From Biot Savart law：

φ=L × I (B4)

φ-by the magnetic flux of core section

L- inductance values

I- exciting currents

And core limb sectional area is：

Bm- magnetic induction

(B4) formula is substituted into (B5) formula, is obtained：

If the inductance value of two independent reactors is identical, L is；Exciting current is respectivelyAnd Choose same magnetic induction density B m, then the column section sum unshakable in one's determination of two is：

In the case of coupling filter reactor, two reactors unite two into one, and exciting current isVector, WithRepresent, at this moment area of core section is：

By vector calculus rule, can obtain,

Therefore have, A_Z3＜ A_Z1+A_Z2, show that coupling filter reactor has less area of core section.

So, couple the iron core of the iron core certainly less than traditional structure of filter reactor.Less generation unshakable in one's determination is less Loss, consumes less copper cash, reduces cost, also reduce size and weight.

In addition, in the manufacture process of reactor, processing unshakable in one's determination and coil winding are requirement highests, ring when most taking a lot of work Section, was changed into one from two iron cores are processed originally, and was changed into three from six coils of coiling, greatly reduces workload, and this is undoubtedly Meeting improve production efficiency, reduces production cost.

Coupling filter reactor occurs because of circuits improvement, and unique structure makes which be respectively provided with biography in application and manufacture link The system incomparable superiority of structure, be same type filter reactor manufacture and design new invention, new technique, tradition can be substituted Structure, with good development prospect.

Embodiment one：By taking the inductance of 7.5KW wave filter as an example

First, basic parameter：

Inductance value：

Inductance code name	Inductance value (mH)
		L1	16.8
L2	0.8

Electric current：

2nd, exciting current is calculated

As it was previously stated, the electric current of L1, L2 is jointly to iron core excitation, by Vector modulation rule, one by one to each harmonic excitation Electric current is calculated, as a result such as following table：

3rd, magnetic circuit parameters are calculated

According to inductance value and exciting current data, the number of turn of L1, L2 is chosen；Determine area of core section, air gap；Calculate each time Harmonic wave and the corresponding magnetic induction of peak excitation electric current, and ensure that, under peak magnetic induction intensity, inductance value fall meets Circuit requirement；Calculate iron core weight and loss.

The number of turn of L1 is 174 circles；

The number of turn of L2 is 38 circles；

Area of core section is 40 × 48 × 0.95=18.16cm²；

Iron core weight is 10.7kg；

Air gap thickness is 4.1mm.

Core loss data see the table below：

4th, wire and copper loss are calculated

Wire gauge is selected by the actual electric current for passing through of L1, L2, copper loss is calculated.

5th, efficiency calculation

Total losses are：196.3W

Efficiency is：97.4%.

6th, temperature rise is calculated

Can see from above calculating process, the determination for coupling filter reactor exciting current is crucial, equal to flowing through two The vector of individual inductive current；And wire gauge and copper loss then depend on flowing through the actual current of two inductance；Other data As calculating and with ordinary reactors being.

Embodiment two：

Fig. 3 is referred to, Fig. 3 is manifold type harmonic filter original structure figure；It includes intermediate node A, input node B, defeated Egress D；

Connect tie point between input node B and the intermediate node A, the tie point includes at least one Individual first inductance L1 ', the first inductance L1 ' and first resistor R1 ' connect；

Connect the second branch road between the intermediate node A and ground G, second branch road includes at least one second inductance L2 ' and at least one capacitor C, the second inductance L2 ', second resistance R2 ' and capacitor C in series；

Thus the tie point and the second branch road constitute low pass Γ mode filter, are manifold type harmonic filter, and defeated Ingress B is used to be connected to power supply；Output node D is used to be connected to load.

The first described inductance L1 ' and the second inductance L2 ' are made as the coupling filter reactor of drop-over.

Fig. 3 (a) is referred to, allows the first inductance L1 ' and the second inductance L2 ' that the contact of magnetic occurs, this two reactors are closed Two is exactly to couple filter reactor for one reactor, and the first inductance L1 ' and the second inductance L2 ' is coupled and made a reactor, And the two inductance are connected into drop-over, its equivalent circuit Fig. 3 (b).

L₁=L₁′+M (B9)

L₂=L₂′+M (B10)

L1- is input into inductance total inductance amount

L2- filter inductance total inductance amounts

The mutual induction amount of two inductance of M-

L1 '-input inductance self-inductance

L2 '-filter inductance self-inductance

The coefficient of coup of two inductance of K-

The first inductance L1 ' and the second inductance L2 ' in the present embodiment is the coupling filter reactor in embodiment one.

Embodiment three：

Fig. 4 is referred to, Fig. 4 is manifold type LCL filter structure chart；It includes intermediate node A, input node B, output section Point D；

Connect the second branch road between the intermediate node A and described output node D, second branch road is included at least One the second inductance L2 ', the second inductance L2 ' and second resistance R2 ' connect；

Connect the 3rd branch road, including at least one capacitor C between the intermediate node A and ground G；

Thus the tie point, the second branch road and the 3rd branch road constitute the T-shaped wave filter of low pass, are manifold type LCL filtering Device, and input node B be used for be connected to inverter；Output node D is used to be connected to load.

Refer to Fig. 4 (a), LCL filter can also make manifold type LCL filter, L1 and L2 couplings make one it is electric Anti- device, and the two inductance are connected into drop-over, its equivalent circuit Fig. 4 (b).

L₁=L₁′+M (B12)

L₂=L₂′+M (B13)

L1- rectification side inductance inductance values

L2- load-side inductance inductance values

The mutual induction amount of two inductance of M-

L1 '-rectification side inductance self-inductance

L2 '-load-side inductance self-inductance

The coefficient of coup of two inductance of K-

It is obvious to a person skilled in the art that the invention is not restricted to the details of above-mentioned one exemplary embodiment, Er Qie In the case of spirit or essential attributes without departing substantially from the present invention, the present invention can be realized in other specific forms.Therefore, no matter From the point of view of which point, embodiment all should be regarded as exemplary, and be nonrestrictive, the scope of the present invention is by appended power Profit is required rather than described above is limited, it is intended that all in the implication and scope of the equivalency of claim by falling Change is included in the present invention.Any reference in claim should not be considered as and limit involved claim.

Moreover, it will be appreciated that although this specification is been described by according to embodiment, not each embodiment is only wrapped Containing an independent technical scheme, this narrating mode of description is only that those skilled in the art should for clarity Using description as an entirety, the technical scheme in each embodiment can also Jing it is appropriately combined, form those skilled in the art Understandable other embodiment.

Claims

1. coupled filter, it is characterised in that：In having three or more than three branch roads and having the filter circuit of common node, Reactor in two or more branch roads is made manifold type reactor, and positive connection, electric capacity and resistance etc. is then mixed Components and parts constitute coupled filter, wherein, manifold type reactor is because there is a mutual inductance in two reactors for intercoupling Amount, and they are positive connections, therefore the total inductance amount of reactor is equal to its self-inductance plus mutual induction amount, so making coupling The self-inductance of two reactors of box-like reactor can take a little bit smaller.

2. coupled filter according to claim 1, it is characterised in that the electricity in described coupled filter circuit Anti- device, is that two reactors independent mutually in traditional circuit are united two into one, makes a reactor, every phase core of its iron core Two coils for flowing through out of phase exciting curent, and positive series connection are set with post, two coils are mutually coupled, jointly to ferrum Heart excitation.