WO2012007247A1

WO2012007247A1 - Module and arrangement for measuring a high-frequency current through a conductor

Info

Publication number: WO2012007247A1
Application number: PCT/EP2011/060140
Authority: WO
Inventors: Robert Baumgartner; Werner Hartmann; Martin Hergt
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-07-14
Filing date: 2011-06-17
Publication date: 2012-01-19
Also published as: DE102010027130A1

Abstract

The invention relates to an arrangement consisting of printed circuit board modules with integrated coils for measuring a high-frequency current through a conductor. Such a printed circuit board module has a first circuit board unit and a coil that is integrated into the module. The coil consists of a plurality of conductor sections that are electrically connected to one another and is designed such that the cross-section of the coil can be penetrated by the field lines of the magnetic field when current is flowing through the conductor, said magnetic field being generated by the current flow, such that a voltage is induced in the coil. Some of the conductor sections of the coil lie on the upper face and on the lower face of the circuit board unit, and some other conductor sections are designed as vias through the circuit board unit. The conductor sections are connected in series such that said sections form the windings of the coil, conductor sections on the upper face and conductor sections on the lower face being connected to one another by means of the vias.

Description

description

Module and arrangement for measuring a high-frequency current through a conductor

The invention relates to an arrangement consisting essentially of printed circuit board modules with integrated coils for measuring a high-frequency current through a conductor. Electric currents in the high frequency range, eg. In one

Magnitudes of 100MHz, can be determined most accurately with the detection of the magnetic field around the conductor carrying the current. In order to detect the magnetic field, a coil is, for example, arranged on the conductor such that the magnetic field passes through the coil, so that a voltage is induced which can be tapped off at the corresponding contacts of the coil. The structure and arrangement of conductor and coil can be realized differently. For example. Power meters are known as accessories for oscilloscopes (eg Tektronix, TCP305), etc., which are only suitable for measurements in research and development as well as for troubleshooting. Furthermore, for example, the companies LEM (DE 20 2010 000 328 Ul) and Honeywell (EP 0 315 358 A2) offer current sensors which are soldered onto circuit boards, but which are not suitable for high-frequency applications. In addition, the articles "PCB Rogowski Coils Property Relay Protection" by L. Kojovic, "Novel differential protection Systems for improved netword operation reliabili- ty" by L. Kojovic and "Design and characteristics of two roowski coils based on printed circuit boards "C.Quing describes integrated coils in printed circuit boards, although the printed circuit boards can not be freely equipped. The coils described there are only used to measure currents in freely laid lines. It is therefore the object of the present invention to provide a way to measure an RF current through a conductor.

This object is achieved by the inventions specified in the independent claims. Advantageous embodiments emerge from the dependent claims. An inventive module for measuring the current intensity of a high frequency current through a conductor of a carrier board comprises:

a first board unit and

- An integrated in the module coil with a

Cross-sectional area and a longitudinal axis, wherein the coil has a plurality of electrically connected to each other

Having conductor portions and is formed such that when current flows through the conductor, the cross section of the coil of the field lines of the current flow caused by the magnetic field is at least partially enforceable, such that in the coil, a voltage is induced,

in which

- A part of the conductor sections of the coil at the top and at the bottom of the board unit is arranged and another part of the conductor sections of the coil as

Vias formed by the board unit,

- The conductor sections are connected in series such that they form the turns of the coil, wherein

Conductor sections at the top and conductor sections at the bottom are connected to each other via the vias.

The module also has an input contact and an output contact, wherein the input contact is electrically connected to an input of the conductor of the coil and the output contact to an output of the conductor of the coil and wherein the induced current flow through the conductor Voltage at the input contact and the output contact can be tapped. With the input and the output contact, the module can, for example, be soldered to corresponding contact points on the carrier board.

The input contact and the output contact are located on the same side of the module, for example, on the bottom, so that a simple contact with the carrier board is possible.

The module may comprise a second board unit, wherein

- The input contact and the output contact on the side facing away from the first board unit side of the second

Board unit are provided and

the connections between the input contact and the

Input of the coil and between the output contact and the one output of the coil are formed as vias through the second board unit.

This second board unit causes the coil conductor does not come into contact with the conductor of the carrier board.

Alternatively, theoretical could also be for that purpose

Spacers or similar used, which are attached to the module or to the first board unit. Furthermore, a third and a fourth board unit may be provided, wherein

- The third board unit at the second

Board unit side facing away from the first

Board unit is arranged and on its side facing away from the first board unit side has a metal coating,

- The fourth board unit at the first

Board unit side facing away from the second

Board unit is arranged and on its side facing the second board unit side has a metal coating,

- the metal coatings of the third and fourth

Board unit are electrically connected together. These additional board units or the

Metal coatings cause shielding of the coil with respect to the electric field. The metal coating of the third board unit and / or the fourth board unit may or may

be advantageously slotted, so that no induction currents flow in them. The conductor sections of the coil can

be formed on the top and at the bottom of the first board as traces on the board surface and / or

- Be embedded in the surface of the board unit or applied to the surface of the board.

An arrangement according to the invention for measuring the current intensity of a high-frequency current through a conductor has at least a first and a second one of those described

inventive modules. There are

- The modules arranged such that the conductor between the modules and when current flows through the conductor, the field lines of the caused by the flow of current

Magnetic field the cross sections of the coils of the modules

enforce, such that in the coils one each

Voltage is inducible,

- the output contact of the first module and the

Input contact of the second module electrically connected to each other, such that when current flows through the

Ladder add the voltages induced in the individual coils, so that between the input contact of the first module and the output contact of the second module, a total voltage can be tapped. The conductor may, for example, be formed as a planar conductor track on or in the surface of the carrier board. The first module can with its input and

Output contacts of its integrated coil at the top of the carrier board and the second module with its input and output ^{contacts of} its integrated coil at the

Bottom of the carrier board arranged, in particular

be soldered.

The electrical connection between the output contact of the coil of the first module and the input contact of the coil of the second module can as through-hole through the

Carrier board of the conductor to be formed.

For picking up the total voltage, at least one conductor track to the input contact of the first module and at least one conductor track to the output contact of the second module can be provided on the carrier board. It can be one of these

Tracks at least in sections as well

Via be formed by the carrier board. In one embodiment of the arrangement, the first and second modules are not identical. The first module which is placed on top of the carrier board, i. on the side where the conductor is located, has at least the first and the second board unit. The second board unit causes the isolation of the coil of the first module of the conductor. The second module has only the first board unit and no second one

Board unit, because insulation between the coil of the second module and the conductor is already effected by the carrier board, so that the provision of a second

PCB unit is redundant in the second module.

Further advantages, features and details of the invention ^¬ give themselves playing from the exemplary embodiments described below and from the drawings.

Showing: Figure 1 is a plan view of an inventive Anord ^¬ voltage for current measurement,

2 shows the arrangement before assembly in side view,

FIG. 3 a top view of a module according to the invention

FIG. 4 shows a further embodiment of the module in side view,

5 is a plan view of a metal coating with egg ^¬ nem through slot,

Figure 6 shows a module consisting of only one circuit board.

In the figures, identical or corresponding areas, components, component groups or method steps are identified by the same reference numerals. Components of the illustrated objects, which would not be visible depending on the selected view, since other components are in front of it, are usually symbolized by dashed lines.

1 shows a side view of a conductor 310, which is, for example, as a planar line on or in a surface at the top of a carrier board 300. Through the conductor 310 flows to be measured high-frequency alternating current I, which is known to generate a corresponding alternating magnetic field around the conductor 300. Above the carrier board 300 and the conductor 310, a module 100 according to the invention for measuring the current intensity of the high-frequency current I is arranged. Below the carrier board 300 or on the underside of another module 200 is arranged that is substantially identical to the first module 100 is formed.

The module 100 consists in the first shown here

Embodiment of two juxtaposed boards 110, 120. The conductor 310 facing away from the board 110 of the module 100 has a coil 130 which is arranged such that the magnetic field generated by the RF alternating current I induces a voltage U in the coil (hereinafter, the carrier board 300 facing side of Module or a board as the bottom and the carrier board side facing away from the top). The function of the board 310 facing the conductor 120 of the module 100 is essentially to prevent electrical contact between the coil 130 and the conductor 310. As will be explained below for the second module 200, this second board can in principle be dispensed with if it can be ruled out that an electrical connection between the coil and the conductor can be excluded

Contact is producible. This is the case, for example, when the module on the opposite side of the conductor

Carrier board is arranged or in the event that the conductor is integrated into the carrier board.

The coil 130 has a longitudinal axis S and a

Cross-sectional area A and is, for example, arranged so that the longitudinal axis S perpendicular to the conductor 310 and to

Current direction of the alternating current I is arranged. The measurement of the induced voltage U is known to allow

Conclusions about the current I.

Figure 2 shows a plan view of the module 100, i. the view in the negative z-direction, from which the arrangement and the basic structure of the coil 130 is clear. The coil 130 consists of a plurality of consecutively

switched conductor sections 130/1, 130/2, 130/3, ... 130/9, wherein the conductor sections 130/1, 130/5, 130/9 at the

Top and the conductor sections 130/3, 130/7 at the

Bottom of the board 110 are arranged. Conductor sections on the top of the board are with

Conductor sections on the bottom of the board over

Through-hole 130/2, 130/4, 130/6, 130/8 through the

Plantine 110 interconnected, so that ultimately the Turns of a coil are formed. The

Vias 130/2, 130/4, 130/6, 130/8 themselves thus also represent conductor sections of the coil 110. The conductor sections 130/3, 130/7 at the bottom of the

Circuit board, which would not be visible in the view of Figure 2, are shown in dashed lines.

The input E130 of the coil 130 is provided on the first conductor section 130/1 and the output A130 of the coil is provided on the last conductor section 130/9. The module 100 has a

Input contact 140 and an output contact 150, wherein the input E130 via a further via, which both the first 110 and the second board 120th

is crossed, connected to the input contact 140.

Accordingly, the output A130 of the coil is with the

Output contact 150 electrically connected. The voltage U induced in the coil 130 during current flow through the conductor 310 can therefore be picked up at the input and output contacts 140, 150 of the module 100.

The module 100 is in the installed state for measuring the current I in the conductor 310 with the input and the

Output contact 140, 150 soldered to corresponding contact points 320, 330 of the carrier board 300 of the conductor 310.

The further module 200 is also three-ply of two

Boards 210, 220 built. The conductor 210 facing away from the board 210 of the module 200 has a coil 230 which is arranged such that the magnetic field generated by the RF alternating current I induces a voltage U in the coil.

The function of the conductor 310 facing the board 220 is essentially to prevent electrical contact between the coil 130 and the conductor 310. As already indicated above, in the case of the arrangement shown here, the second circuit board 220 of the second module 200 can be dispensed with, since the carrier circuit board 300 itself is used as a

Insulation between the coil 230 of the second module 200 and the conductor 310 acts. It brings however production-technical Advantages, if the first and the second module are identical. On the other hand, the two-ply design of the second module with only a single board would be less expensive.

The coil 230 is also arranged so that its longitudinal axis perpendicular to the conductor 310 and to the current direction of the

AC I is arranged. Figure 3 shows a plan view of the second module 200, i. the view in positive z-direction. The coil 230 also consists of a plurality of conductor sections 230/1, 230/2, 230/3,... 230/9, wherein the conductor sections 230/3, 230/7 on the upper side and the conductor sections 230/1, 230 / 5, 230/9 are arranged on the underside of the board 210. As in the case of the first module, a conductor portion on the top of the board is connected via a via to a conductor portion on the underside of the board so that the conductor portions ultimately form a coil of substantially rectangular cross-section.

At the first conductor section 230/1 of the coil 230 of the second module 200, the input E230 of the coil 230 and at the last conductor section 230/9 the output A230 of the coil 200

intended. The module 200 has an input contact 240 and an output contact 250, wherein the input E230 is connected to the input contact 240 via a further through-connection 230/10, 230/11, which passes through both the first 210 and the second circuit board 220. Accordingly, the output A230 of the coil is electrically connected to the output contact 250. The voltage U induced in the coil 230 during current flow through the conductor 310 can thus be picked up at the input and output contacts 240, 250 of the module 200.

Also, the module 200 is in the installed state for measuring the current I with the input and the output contact 240, 250th soldered to corresponding contact points 340, 350 of the carrier board 300 of the conductor 310.

The modules 100, 200 are electrically connected to one another in the installed state in such a way that the voltages induced in the two coils add up. For this is the

Output A130 of the coil 130 of the first module 100 is connected to the input E230 of the coil 230 of the second module 200. This is done through a via 360 through the

Carrier board 300 realized, which connects the contact points 330, 340 with each other.

In order to finally pick up and quantify the voltage to be measured, the contact points 320, 350 can be connected to a measuring device (also not shown) via corresponding conductor tracks (not shown here) of the carrier board 300. This may, for example, also be soldered onto the carrier board 300 as a component. Particularly advantageous effect in the module an addi ^¬ che, the coil each surrounding insulated conductor level, which is not connected to the coil itself but only with the ground ^¬ reference potential of the carrier board and mindes ^¬ least on one side of the coil to be measured by a Head has away pointing air gap. This is illustrated for the first Mo ^¬ dul 100 in FIG. 4 The module 100 has upper ^¬ and below the sketched in the figure 1 structure per ^¬ weils another board 160 or 170 on. On the side facing away from the Lei ^¬ ter 310 of the board 160 and on the side facing away from the conductor of the board 170 each have a Me ^¬ tallschicht 161 and 171 is provided. The metal layers 161, 171 are electrically connected to vias 180 by the intermediary boards. Furthermore, the metal layers may be connected to a ground contact on the carrier board 300 (not shown), if any. The input contact 140 and the output contact 150, with the input E130 or the

Output A130 of the coil 130 are connected in this Embodiment on the support plate 300 facing side of the additional board 170 is provided.

So that no induction current flows in the shield, for example, the metal layer 161 should be made slotted. As shown in Figure 5 in a top view of the module 100 in the embodiment of Figure 4 takes the Schlit ^¬ pollution, here consisting of a through slit 162, in the direction in which the coil is wound, that is, in the y direction , Since the coil will be ^¬ 130 perpendicular to the conductor 310, the air gap is so ^¬ facing from the conductor to be measured away. This is advantageous in that, a ^¬ scatters an electric field can be reduced to the coil, whereby the signal-to-noise ratio lent German is increased.

For the second module 200 the same applies, that also may be provided in a manner analogous additional boards with entspre ^¬ sponding, possibly slotted metal layers.

The coils 100, 200 shown in FIGS. 2 and 3 have a comparatively small number of windings for the sake of clarity. In practice, a much higher number of turns is provided.

In principle, it would also be sufficient to provide only one of the modules, for example the first module 100, for measuring the current or the magnetic field generated by the current.

Accordingly, the plated-through hole 360 as well as the contact points 340, 350 could be dispensed with. The induced voltage would then be tapped at the contact points 320, 330.

In determining the thicknesses of the individual boards a compromise between compactness of the module, suffi ^¬ chender mechanical stability and functional performance of the coil must be found. Although comparatively large layer thicknesses bring about good stability and a large coil thickness. cross-section, however, the module is correspondingly thick. For ei ^¬ ne AC frequency of about 150 MHz, for example, layer thicknesses of about 1mm are suitable.

The coils 130, 230 are aligned in a substantially rectangular cross section, that the conductor portions of one turn are pa rallel ^¬ each other. In other words, the conductor sections of a turn essentially form a parallelogram, wherein the corners can certainly also be rounded.

It has already been mentioned that the second module 200 can consist of only one circuit board 210. In this case, the input contact 240 and the output contact 250 would be attached directly to the side of the board 210 facing the carrier board 300. This is shown in FIG.

Claims

claims

1. Module (100, 200) for measuring the amperage of a

High frequency current through a conductor (310) a

Carrier board (300), comprising

- A first board unit (110, 210) and

a coil (130, 230) integrated into the module (100, 200) with a cross-sectional area (A) and a longitudinal axis (S), the coil (130, 230) having a multiplicity of conductor sections (130/1, ..., 130/11,

230/1, 230/11) and is formed such that when current flows through the conductor (310), the cross section of the coil (130, 230) from the field lines of the through

Current flow induced magnetic field is at least partially enforceable, such that in the coil (130, 230) a

Voltage (U) is induced

in which

a part of the conductor sections of the coil (130, 230) is arranged on the upper side and on the underside of the sinker unit (110, 210) and a further part of the

Conductor portions of the coil (130, 230) as

Vias formed by the board unit (110, 210),

- The conductor sections are connected in series such that they form the turns of the coil (130, 230), wherein

2. Module according to claim 1, characterized in that the module (100, 200) has an input contact (140, 240) and an output contact (150, 250), wherein the

Input contact (140, 240) having an input (E130, E140) of the conductor of the coil (130, 230) and the output contact (150, 250) to an output (A130, A230) of the conductor of the coil (130, 230) electrically connected is and where the at

Current flow through the conductor (310) induced voltage at the Input contact (140, 240) and the output contact (150, 250) can be tapped off.

3. Module according to claim 1 or 2, characterized in that the module (100, 200) has a second board unit (120, 220), wherein

- The input contact (140, 240) and the output contact

(150, 250) on the first board unit (110, 210) facing away from the second board unit (120, 220) are provided and

- The connections between the input contact (140, 240) and the input (E130, E230) of the coil (130, 230) and between the output contact (150, 250) and the one

Output (A130, A230) of the coil (130, 230) as

Vias through the second board unit (120,

220) are formed.

4. Module according to claim 3, characterized in that a third (160) and a fourth board unit (260) are provided, wherein

- The third board unit (160) at the second

Board unit (120) facing away from the first

Board unit (110) is arranged on its side facing away from the first board unit (110) side

Having metal coating (161),

the fourth board unit (170) at the first one

Board unit (110) facing away from the second

Board unit (120) is arranged and on its side facing the second board unit (120) side

Having metal coating (171),

- The metal coatings (161, 171) of the third (160) and the fourth board unit (170) are electrically connected together.

5. Module according to claim 4, characterized in that the metal coating (161, 171) of the third board unit (160) and / or the fourth board unit (170) is slotted.

6. Module according to one of the preceding claims, characterized in that the input contact (140, 240) and the output contact (150, 250) on the same side of the module (100, 200), in particular at the bottom, are.

7. Module according to one of the preceding claims, characterized in that the conductor sections of the coil (130, 230) at the top and at the bottom of the first

Board (110, 210) are formed as conductor tracks on the board surface.

8. Module according to one of the preceding claims, characterized in that the conductor sections of the coil (130, 230) in the surface of the board unit (110, 210)

embedded or on the surface of the board unit (110, 210) are applied.

9. Arrangement for measuring the current of a

High frequency current through a conductor (310), at least with a first module (100) and a second module (200), wherein the first and the second module each according to one of

Claims 1 to 8 are formed, wherein

- The modules (100, 200) are arranged such that the

Conductor (310) runs between the modules (100, 200) and, when current flows through the conductor (310), the field lines of the magnetic field caused by the current flow

Cross sections of the coils (130, 230) of the modules (100, 200) enforce, such that in each case a voltage is inducible in the coils (130, 230),

- The output contact (150) of the first module (100) and the input contact (240) of the second module (200) are electrically connected together, such that at

Current flow through the conductor (310) add the voltages induced in the individual coils, so that between the input contact (140) of the first module (100) and the output contact (250) of the second module (200)

Total voltage can be tapped.

10. Arrangement according to claim 9, characterized in that the conductor (310) as a planar conductor track on or in the

Surface of a carrier board (300) is formed.

11. Arrangement according to claim 10, characterized in that the first module (100) with its input and

Output contacts (140, 150) of its integrated coil (130) at the top of the carrier board (300) and the second module (200) with its input and output contacts (240, 250) of its integrated coil (230) at the bottom of the

Carrier board (300) arranged, in particular soldered, is.

12. Arrangement according to claim 10 or 11, characterized

characterized in that the electrical connection between the output contact (150) of the coil (130) of the first module (100) and the input contact (240) of the coil (230) of the second module (200) as a via (360) through the

Carrier board (300) of the conductor (310) is formed.

13. Arrangement according to one of claims 10 to 12, characterized in that for tapping the total voltage on the carrier board (300) at least one conductor track to

Input contact (140) of the first module (100) and at least one conductor to the output contact (250) of the second module (250) is provided.

14. Arrangement according to one of claims 9 to 13, characterized in that

- The first module (100) on the upper side of the carrier board (300) at least the first (110) and the second

Comprising board unit (120) and

- The second module (200) on the underside of the carrier board (300) has no second board unit (220).