DE202016104544U1 - Multi-phase push-pull power choke - Google Patents

Abstract

A multi-phase push-pull power choke (10) for attenuating transient push-pull currents between an at least two-phase power source (20) and an electrical load having a corresponding number of phases, the power source (20) having an at least two-phase first power source (20a) and a parallel at least two-phase second energy source (20b), and corresponding phases of the first and second energy source (20a, 20b) are each coupled to one another via a throttle unit (12), characterized in that for reducing stray magnetic fields at least two throttle units (12), which are arranged in different phases, are magnetically coupled to one another via at least one multi-phase magnetic shunt (24).

Description

The invention relates to a polyphase push-pull power choke for damping transient push-pull currents between an at least two-phase power source and an electrical load having a corresponding number of phases, wherein the power source is an at least two-phase first power source and an at least two-phase second power source connected in parallel thereto, and each other corresponding phases of the first and second energy source are each coupled to one another via a throttle unit.

Differential mode currents are reduced or eliminated by the impedances of a push-pull choke. Such disturbances arise, for example, as harmonics in switching power supplies and have, in contrast to the useful current against each other directed polarities.

To increase the output power, it is also known in electrical systems, parallel to switch energy sources, such as inverters. This applies to both two-phase and three-phase systems. The parallel electrical energy sources have the same number of phases, in addition, the output voltages and their operating frequencies are the same. These systems are mainly used as two-phase or three-phase systems. In a three-phase system, the three phases have a phase angle of 120 °. The individual phase currents are thus phase-shifted by 120 °.

The clocked inverters often used today as an energy source generate a relatively wide harmonic spectrum in addition to a working current, ie direct current or an alternating current with a given main frequency. This results in transient push-pull currents that circulate in the same phase lines before the output terminal. Such equalizing currents cause not only increased losses but also harmonic distortion.

Mains chokes are used to reduce the harmonics. For small and medium powers, push-pull chokes are used to dampen the transient differential currents on the electronic voltage transformers or frequency converters. A push-pull choke comes for example in the from EP 2 814 151 A1 known inverter used.

In a push-pull choke, the two coils are magnetically coupled to each other so that the resulting inductance for the compensation currents is greater than the inductance for the working current.

In 1 For example, a single-phase choke is shown schematically. It includes a magnetic core 2 of type UI. The core 2 includes a first leg 4_1 and a second leg 4_2 , the end over an upper yoke 6_1 and a lower yoke 6_2 are magnetically coupled together.

In the thighs 4_1 . 4_2 There are air gaps. They are distributed over several widths in order to avoid heat development in the gap area. In 1 For example, only a gap provided with reference numerals. On the first thigh 4_1 there is a first winding 8_1 , On the second leg 4_2 there is a second winding 8_2 ,

The peculiarity of a push-pull choke is that in each case a self-inductance L and a mutual inductance M with M <L are defined for the two magnetically connected windings. For the working currents flowing through the coil in one direction, the inductance for both coils is 2 · (L - M). By contrast, for the equalizing currents flowing in opposite directions, the inductance of the two coils is 2 · (L + M). The relationship between L and M is described by the coupling factor k as follows: M = k · L. To set the necessary ratio between L and M is located between the first leg 4_1 and the second leg 4_2 a third leg 4_3 acting as a single phase magnetic shunt. Also in the single-phase magnetic shunt several air gaps are present. This single-phase magnetic shunt affects the magnetic coupling of the two windings 8_1 . 8_2 ,

The technical disadvantage of a schematic in 1 shown and known per se push-pull throttle is now that the working currents in the cores cause magnetic currents that flow in one direction and therefore generate a correspondingly large stray magnetic field SF (shown schematically). Magnetic stray fields SF generate undesired heating of adjacent metallic components, for example the walls of a control cabinet. In addition, stray magnetic fields SF cause interference in sensitive electronic devices and are undesirable for this reason as well.

Object of the present invention is to provide a polyphase push-pull power choke, which generates lower stray magnetic fields and at the same time has a compact design.

The object is achieved by a multi-phase push-pull power choke for damping transient push-pull currents between an at least two-phase power source and a electrical load having a corresponding number of phases, wherein the power source is an at least two-phase first power source and a parallel connected at least two-phase second power source, and corresponding phases of the first and second power source are each coupled via a throttle unit with each other, wherein the push-pull power choke is further developed in that for reducing stray magnetic fields at least two throttle units, which are arranged in different phases, are magnetically coupled to each other via at least one multi-phase magnetic shunt.

Advantageously, the polyphase push-pull power choke on a lower stray magnetic field than conventional systems. For this reason, no or at least significantly smaller minimum distances to metallic components in the vicinity of the throttle must be maintained. For example, it is possible to position the push-pull power choke in a control cabinet, without the risk that heat its walls or floor to an undesirable extent. The lower stray magnetic field will also have a positive effect on the electromagnetic compatibility of the push-pull power choke. The system is also extremely compact. The compact design can advantageously be fully utilized because no or only significantly reduced minimum distances to other components must be complied with.

The working current in a first winding of a choke unit, which is in a phase of a first energy source, forms a magnetic flux. The working current in a second winding of a further choke unit, which is located in a like phase of a second energy source, also forms a magnetic flux which flows in the same direction as the first-mentioned magnetic flux. The multi-phase magnetic shunt, which magnetically couples the throttling units in different phases, ensures that the magnetic flux is not displaced into the air by the working current. In multiphase systems, the sum of the working currents in the different phases is equal to zero. For this reason, the sum of the magnetic fluxes produced by the working currents, which are displaced out of the throttle units into the multiphase magnetic shunt, is also equal to zero. In the multi-phase magnetic shunt, the magnetic fluxes eliminate one another, as a result, it is possible to significantly reduce or even completely eliminate the resulting stray field of the push-pull power choke.

According to aspects of the invention, a multi-phase push-pull power choke is advantageously provided, which generates only minimal magnetic stray fields and also has a very compact design. At the same time, it is possible to set the coupling factor flexibly. In summary, therefore, the mechanical, electrical, magnetic and thermal properties of the polyphase push-pull power choke are significantly improved over conventional solutions. This applies to every single one of the properties mentioned above, but above all to the sum of these properties. The multi-phase push-pull power choke is thus distinguished over conventional solutions, especially by the fact that both the mechanical and the electrical, magnetic and thermal properties are simultaneously improved.

According to a further embodiment, an air gap is present in each case between the polyphase magnetic shunt and the yoke of the throttle units. By adjusting a width of these air gaps can advantageously be achieved and flexibly adjusted between the windings of the different throttle units and thereby also between the different phases.

According to an advantageous embodiment, the push-pull power choke is further developed in that the choke units each comprise a first winding and a second winding, which are arranged on a common core, with the polyphase magnetic shunt, the cores of the at least two arranged in different phases throttle units with each other are coupled.

It is provided in particular that the throttle units each comprise between the core and the windings arranged heat sink.

The use of a heat sink allows to increase the performance of the push-pull power choke without increasing their structural dimensions. It is thus advantageously possible to realize a compact design with simultaneously increased performance.

It is further provided in particular that the heat sink have cooling water connections, which are arranged below the windings. The arrangement of the cooling water connections below the windings is advantageous above all because, in the event of a leak at the cooling water connections, there is no risk of cooling water damaging the windings. "Below" in the context of the present description means "geodetically deeper". The cooling water thus flows downwards without the windings being able to get wet.

According to a further embodiment it is provided that the cores with an upper polyphase magnetic shunt and a lower polyphase magnetic shunt are coupled and the cooling water connections between a bottom of the windings and the lower polyphase magnetic shunt are arranged. Due to the arrangement of the cooling water connections between the underside of the windings and an upper side of the lower polyphase magnetic shunt, the structural dimension of the push-pull power choke does not have to be increased for the cooling water connections. Advantageously, the compact design of the push-pull power choke is maintained even with increased power and thereby required cooling.

According to a further advantageous embodiment, it is provided that the core has the shape of a closed yoke, wherein the yoke comprises a first leg, a second leg and an upper and a lower yoke, wherein the two legs at their upper ends on the upper yoke and are magnetically coupled at their lower ends via the lower yoke and wherein the arranged in different phases throttle units are magnetically coupled to each other at the upper yoke with an upper magnetic shunt and at its lower yoke with a lower magnetic shunt.

The embodiment described has proven to be particularly advantageous and flexible in practice. In particular, it is provided in this context that a core with three legs is provided, wherein a third leg, which acts as a two-part magnetic shunt, is disposed between the first and second legs. Via this third leg, which acts as a single-phase magnetic shunt, it is possible to flexibly adjust the magnetic coupling between the two windings. Also, the third leg is magnetically coupled to the upper and lower yoke.

It is advantageously provided that by adjusting the air gaps in the single-phase shunt in the respective throttle units and by adjusting the air gap between the core and the polyphase magnetic shunt, the coupling between the windings of a choke unit (in one phase) and the coupling between the windings of different Throttle units and thus different phases can be flexibly adjusted.

According to an advantageous development it is further provided that between the yoke and the respective multi-phase magnetic shunt, a magnetic resistance, in particular an air gap, is present. Through the air gap, it is possible to adjust the magnetic resistance between the yoke and the multiphase magnetic shunt.

According to a further embodiment it is provided that the core comprises a third leg which extends between the first and the second leg between the upper and lower yoke and forms a single-phase magnetic shunt, wherein a half cross section of the polyphase magnetic shunt plus a cross section of the single-phase magnetic shunt in the sum is smaller than a cross section of the first and second legs, which are surrounded by a respective winding. The multiphase magnetic shunt in many cases includes an upper magnetic shunt and a lower magnetic shunt. A half cross section of the magnetic shunt would thus be, for example, the cross section of the upper or lower shunt. The cross section of the first and the second leg is the sum of the individual cross sections of the legs. In such an embodiment, the core material is used particularly efficiently, the cost of the core material is thus optimized or reduced and the throttle is constructed more compact.

It is known to use a first inverter as the first energy source and a second inverter as the second energy source. The polyphase push-pull power choke may for example be a component of such an inverter. Advantageously, such an inverter supplies AC voltage with less harmonic content.

The first and second energy sources may each have three phases. In three-phase systems, it is inevitable in many cases that a relatively large design must be accepted. However, the compact multi-phase push-pull power choke, which accordingly has three choke units which, as described in the aforementioned embodiments, are coupled together by the multi-phase magnetic shunt has, however, advantageously a particularly compact design.

Further features of the invention will become apparent from the description of embodiments according to the invention together with the claims and the accompanying drawings. Embodiments of the invention may satisfy individual features or a combination of several features.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings, reference being expressly made to the drawings with respect to all in the text unspecified details of the invention. Show it:

1 a simplified schematic representation of a single-phase reactor according to the prior art,

2 a schematically simplified circuit diagram of a two-phase system with two inverters and two throttle units,

3 a schematically simplified circuit diagram of a three-phase system with two inverters and three throttle units,

4a . 4b a two-phase push-pull power choke in two side views offset by 90 ° in the viewing direction,

5a . 5b a three-phase push-pull power choke in two by 90 ° in the viewing direction staggered side views,

6 a schematically simplified perspective view of the 5a and 5b known three-phase push-pull power choke.

In the drawings, the same or similar elements and / or parts are provided with the same reference numerals, so that apart from a new idea each.

2 shows a schematically simplified circuit diagram of a two-phase system comprising a first inverter WR1 and a second inverter WR2. The first inverter WR1 is an exemplary first power source 20a The second inverter WR2 is an exemplary second power source 20b , The two inverters WR1, WR2 together form an energy source 20 of the system. The two inverters WR1, WR2 are connected in parallel. A first phase A1 of the first inverter WR1 is coupled to a corresponding first phase A2 of the second inverter WR2 to phase A of the system. Accordingly, a second phase B1 of the first inverter WR1 is coupled to phase B with a corresponding second phase B2 of the second inverter WR2. At the phases A, B, a load, not shown, is connected.

In phase A there is the choke unit Dr A. Your two windings 8th are schematic in 2 shown. The winding direction of the windings is represented by a dot. In phase B there is a second choke unit Dr B. Your windings 8th are also shown schematically, their winding direction is also indicated by a dot.

3 shows a schematically simplified circuit diagram of a three-phase system, which also includes two inverters, namely the first inverter WR1 and the second inverter WR2, as first and second energy source 20a . 20b includes. In this system, three throttle units Dr U, Dr V and Dr W are provided. Again, the phases U1, V1 and W1 of the first inverter WR1 are coupled together to the respective phases U2, V2 and W2 of the second inverter WR2 to the phases U, V and W of the system. An attached three-phase load is not shown. In the individual phases of the inverters WR1, WR2 are the windings 8th the three throttles Dr U, Dr V and Dr W indicated. Again, the winding directions are indicated by a dot.

In a multi-phase push-pull power choke for damping transient push-pull currents, as shown in the in 2 and 3 systems shown in front of the output terminals A, B and U, V, W circulate in the system, the throttle units Dr A, Dr B and Dr U, Dr V and Dr W in the different phases A, B and U, V, W via at least one multiphase magnetic shunt 24 magnetically coupled with each other. Various embodiments of such push-pull power chokes are shown in the following figures.

The 4a and 4b show in 90 ° in the viewing direction offset from each other side views a two-phase push-pull power choke 10 , The push-pull power choke 10 includes a first throttle unit 12_1 and a second throttle unit 12_2 , Each of the throttle units 12_1 . 12_2 includes, as in principle by means of 1 explains, two windings 8th , respectively, as related to 2 are coupled to a phase of a first energy source and a phase of a second energy source. The throttle units are generally denoted by reference numerals 12 designated.

The first throttle unit 12_1 the in 4a shown two-phase push-pull power choke 10 includes a first core 2_1 who is one in 4a visible first leg 4_11 and one in 4a concealed second leg comprises. The two legs of the first core 2_1 are above a first upper yoke 6_11 and a first lower yoke 6_21 magnetically coupled with each other. On the first thigh 4_11 there is a first winding 8_11 , on the second leg there is a second winding (not visible).

The second core 2_2 the second throttle unit 12_2 is analogous to the first core 2_1 the first throttle unit 12_1 built up. It includes a first leg 4_21 and a second in 4a invisible thighs 4_22 (see. 4b ). The first and the second leg 4_21 . 4_22 are about that upper yoke 6_21 and the lower yoke 6_22 coupled together. On the first thigh 4_21 there is a first winding 8_21 , on the second leg 4_22 there is a second winding 8_22 ( 4b ).

In addition, the cores include 2_1 . 2_2 the throttle units 12_1 . 12_2 each a third leg 4_32 , which is for the second throttle unit 12_2 in 4b is shown.

Between the thighs, also generally with reference numerals 4 be designated, and the yoke, also generally with reference numerals 6 are to be designated, are each air gaps 14 provided over the width of the magnetic resistances between the core parts are adjusted.

Those in the different phases A, B or U, V, W ( 2 and 3 ) arranged throttle units 12 are over a multi-phase magnetic shunt 24 magnetically coupled with each other. This is in the in 4a and 4b shown embodiment, an upper multi-phase magnetic shunt 24_1 and a lower multi-phase magnetic shunt 24_2 intended. The magnetic coupling of the multiphase shunt, generally designated by reference numerals 24 is set above the upper distance d1 and the lower distance d2. Between the upper multiphase magnetic shunt 24_1 and the upper yoke 6_11 . 6_21 and also between the lower multiphase magnetic shunt 24_2 and the lower yoke 6_12 . 6_22 each is an air gap 30 intended.

In 4b is shown to be the upper multiphase magnetic shunt 24_1 from two upper shunt parts 24_11 . 24_12 is constructed. Correspondingly, the lower multiphase magnetic shunt is 24_2 from two lower shunt parts 24_21 and 24_22 built up. The thigh 4 the throttle units 12 are also with heatsinks 26 Mistake. The heat sinks 26 are between the core 2 and the windings 8th between the thighs 4 and the windings 8th arranged. The heat sinks 26 include cooling water connections 28 that are underneath the windings 8th are arranged. The cooling water connections 28 are located between an upper side of the lower multiphase magnetic shunt 24_2 and a bottom of the windings 8th ,

The components of the core 2 and also the multiphase magnetic shunt 24 are preferably laminated core parts, which are made for example of transformer sheet. A stacking direction of the sheets is also indicated in the figures.

4b shows a side view of the in 4a Direction designated IVb. 4a shows a side view of the push-pull power choke 10 from the in 4b with direction IVa.

5a shows a side view of a three-phase push-pull power choke 10 , Visible is a first throttle unit 12_1 comprising a core 2_1 who has a first thigh 4_11 and a second leg 4_12 includes, at its upper and lower ends with an upper yoke 6_11 and a lower yoke 6_12 are coupled. Again, between the thighs 4_11 . 4_12 and the yoke 6_11 and 6_12 air gaps 14 intended. A first winding 8_11 surrounds the first leg 4_11 and a second winding 8_12 surrounds the second leg 4_12 , Between the windings 8_11 . 8_12 and the respective leg 4_11 . 4_12 are each heat sink 26 , At the bottom of the heat sink 26 are cooling water connections 28 intended. These are located in an air gap 30 between the lower yoke 6_12 and the lower multiphase magnetic shunt 24_2 , The air gap 30 has the width d2. Between the upper yoke 6_11 and the upper multi-phase magnetic shunt 24_1 is also an air gap 30 intended. This has the width d1.

5b shows a side view of the three-phase push-pull power choke 10 from the in 5a with Vb designated direction. Visible are the first throttle unit 12_1 , a second throttle unit 12_2 and a third throttle unit 12_3 , The cores 2_1 . 2_2 and 2_3 , more exactly the yoke 6_11 . 6_21 and 6_31 respectively. 6_12 . 6_22 and 6_32 are above the upper and lower multiphase magnetic shunt 24_1 respectively. 24_2 magnetically coupled with each other. There is a corresponding distance d1, d2 between the upper yoke 6_11 . 6_21 and 6_31 and the upper multi-phase magnetic shunt 24_1 and a distance d2 between the lower yoke 6_12 . 6_22 . 6_32 and the lower multiphase magnetic shunt 24_2 intended. Again it is between the windings 4_12 . 4_22 . 4_32 and thighs 4_12 . 4_22 . 4_32 a heat sink 26 , Of course, this also applies to the in 5b facing away and invisible legs and windings.

6 shows in a schematically simplified perspective view of the 5a and 5b already known three-phase push-pull power choke 10 , The upper and lower multiphase magnetic shunt 24_1 . 24_2 each consists of two shunt parts 24_11 . 24_12 respectively. 24_21 . 24_22 (invisible). The components are made in particular of electrical sheets and with appropriate screws 32 package advantage. There is also a holder 34 provided, which consists of cross struts and Longitudinal struts exist, with the whole push-pull power choke 10 is held together.

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features. In the context of the invention, features which are identified by "particular" or "preferably" are to be understood as optional features.

LIST OF REFERENCE NUMBERS

2

core

4

leg

6

yoke

8th

windings

10

Push-pull power reactor

12

restrictor

12_1

first throttle unit

12_2

second throttle unit

12_3

third throttle unit

14

air gap

20

energy

20a

first source of energy

20b

second energy source

24

multiphase magnetic shunt

24_1

Upper polyphase magnetic shunt

24_2

lower multiphase magnetic shunt

26

heatsink

28

Cooling water connection

30

air gap

32

screw

34

brackets

WR1

first inverter

WR2

second inverter

d1

upper distance

d2

lower distance

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2814151 A1 [0005]

Claims (8)

Multi-phase push-pull power choke ( 10 ) for attenuating transient push-pull currents between an at least two-phase energy source ( 20 ) and an electrical load having a corresponding number of phases, wherein the energy source ( 20 ) an at least two-phase first energy source ( 20a ) and an at least two-phase second energy source connected in parallel thereto ( 20b ), and corresponding phases of the first and second energy sources ( 20a . 20b ) each via a throttle unit ( 12 ) are coupled to each other, characterized in that for reducing stray magnetic fields at least two throttle units ( 12 ), which are arranged in different phases, via at least one multiphase magnetic shunt ( 24 ) are magnetically coupled with each other. Push-pull power choke ( 10 ) According to claim 1, characterized in that the throttling units ( 12 ) each have a first winding ( 8th ) and a second winding ( 8th ) based on a common core ( 2 ) are arranged, with the multiphase magnetic shunt ( 24 ) the cores ( 2 ) of the at least two throttle units arranged in different phases ( 12 ) are coupled together. Push-pull power choke ( 10 ) according to claim 2, characterized in that the throttling units ( 12 ) between the core ( 2 ) and the windings ( 8th ) arranged heat sink ( 26 ). Push-pull power choke ( 10 ) according to claim 3, characterized in that the heat sinks ( 26 ) Cooling water connections ( 28 ), which are below the windings ( 8th ) are arranged. Push-pull power choke ( 10 ) according to claim 4, characterized in that the cores ( 2 ) with an upper polyphase magnetic shunt ( 24_1 ) and a lower polyphase magnetic shunt ( 24_2 ) and the cooling water connections ( 28 ) between a bottom of the windings ( 8th ) and the lower multiphase magnetic shunt ( 24_2 ) are arranged. Push-pull power choke ( 10 ) according to one of claims 2 to 5, characterized in that the core ( 2 ) has a closed shape, comprising a first leg ( 4_1 ) on which the first winding ( 8th ) is arranged, a second leg ( 4_2 ) on which the second winding ( 8th ), as well as an upper and a lower yoke ( 6_1 . 6_2 ), the two legs ( 4_1 . 4_2 ) at their upper ends via the upper yoke ( 6_1 ) and at their lower ends over the lower yoke ( 6_2 ) are magnetically coupled and wherein the arranged in different phases throttle units ( 12 ) at the upper yoke ( 6_1 ) with a polyphase upper magnetic shunt ( 24_1 ) and at its lower yoke ( 6_2 ) with a polyphase lower magnetic shunt ( 24_2 ) are magnetically coupled with each other. Push-pull power choke ( 10 ) according to claim 6, characterized in that between the yoke ( 6 ) and the respective multi-phase magnetic shunt ( 24 ) a magnetic resistance, in particular an air gap ( 30 ), is available. Push-pull power choke ( 10 ) according to claim 6 or 7, characterized in that the core ( 2 ) a third leg ( 4_3 ) extending between the first and second legs ( 4_1 . 4_2 ) between the upper and lower yoke ( 6_1 . 6_2 ) and forms a single-phase magnetic shunt, wherein a half cross section of the multiphase magnetic shunt ( 24 ) plus a cross section of the single-phase magnetic shunt in the sum is smaller than a cross section of the first and second leg ( 4_1 . 4_2 ), each of which has one winding ( 8th ) are surrounded.

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