WO2019174916A1

WO2019174916A1 - Transformer, voltage converter and method for transmitting electric power

Info

Publication number: WO2019174916A1
Application number: PCT/EP2019/054874
Authority: WO
Inventors: Johann W. Kolar; Dominik Bortis; Jannik Robin SCHAEFER
Original assignee: Robert Bosch Gmbh
Priority date: 2018-03-14
Filing date: 2019-02-27
Publication date: 2019-09-19
Also published as: DE102018203888A1

Abstract

The present invention relates to the transmission of electric power by means of a transformer for a three-port voltage converter. For this purpose, there is in particular provision for an additional winding that can be included in the power transmission or not, depending on the mode of operation of the voltage converter.

Description

description

title

Transformer, voltage converter and method for transmitting electrical energy

The present invention relates to a transformer, a voltage converter with a transformer and a method for transmitting electrical energy by means of such a transformer. In particular, the present invention relates to the transmission of electrical energy by means of a three-port voltage converter.

State of the art

Electric and hybrid vehicles usually have two different electrical systems. In a low-voltage network, which is buffered by an accumulator, all low-voltage consumers, such as on-board computers, lighting units and consumer electronics are usually supplied. In addition, a high-voltage network, which is powered by a high-voltage accumulator, provides electrical energy for the drive. In particular, the electrical energy for the low voltage network of the

High voltage side can be provided. You can do this

DC-DC converter are used, which must have a galvanic isolation between the high-voltage network and the low-voltage network for safety reasons.

In addition, the accumulators of an electric or hybrid vehicle can be charged via an external power supply. For this purpose, too, a galvanic isolation is to be provided for safety reasons, so that there exist in total three mutually galvanically isolated voltage systems. Document DE 10 2017 222 087 A1 discloses a transformer structure for a three-port resonant converter for transmitting electrical energy between three voltage systems. In particular, a transformer with a total of five windings is provided. By selective control of the individual windings, the transmission between the individual

Voltage systems are controlled.

Disclosure of the invention

The present invention provides a transformer with the features of claim 1, a three-port voltage converter with the features of claim 8 and a method for transmitting electrical energy with the features of claim 9.

Accordingly, it is provided:

A transformer for a three-port voltage converter having a first annular transformer core and a second annular one

Transformer core. The transformer also includes a first one

Primary winding disposed on the first transformer core and a second primary winding disposed on the second transformer core. Furthermore, the transformer core comprises a first secondary winding, which is arranged on the first transformer core, a second secondary winding, which is arranged on the second transformer core, and a third

Secondary winding, which is arranged both on the first transformer core as well as on the second transformer core. Finally, the transformer includes a tertiary winding disposed on the first transformer core and on the second transformer core. The first secondary winding, the second secondary winding and the third secondary winding each have a first terminal and a second terminal. In particular, in each case the first terminal of the first secondary winding, the first terminal of the second secondary winding and the first terminal of the third secondary winding are electrically connected to one another at a common node. Furthermore, it is provided:

A three-port voltage converter with a transformer according to the invention, a first drive circuit, a second drive circuit and a rectifier circuit. The first drive circuit is designed to provide a first AC voltage to the first primary winding and to provide a second AC voltage to the second primary winding. The second drive circuit is designed to rectify an electrical alternating voltage applied between the second terminal of the first secondary winding and the second terminal of the second secondary winding. The second drive circuit is further configured to provide an AC voltage between the second terminal of the first secondary winding and the second terminal of the third secondary winding and also to provide an AC voltage between the second terminal of the second secondary winding and the second terminal of the third secondary winding.

The rectifier circuit is designed to rectify a voltage applied to the tertiary winding AC voltage.

Finally, it is planned:

A method for transmitting electrical energy by means of a transformer according to the invention. The method includes a step of providing a first AC voltage between the second terminal of the first secondary winding and the second terminal of the third one

Secondary winding. Furthermore, the method comprises a step for

Providing a second AC voltage between the second terminal of the second secondary winding and the second terminal of the third one

Secondary winding. Finally, the method includes a step of rectifying an electrical induced at the tertiary winding

AC voltage.

Advantages of the invention

The present invention is based on the knowledge that the

Transformers as used in conventional voltage transformers be, usually have fixed voltage transfer ratios.

These voltage transfer ratios can be optimized, for example, for a selected operating mode. In such a case, however, the efficiency or the efficiency drops in the other operating modes.

It is therefore an idea of the present invention to take this knowledge into account and provide a configuration of a three-port voltage converter with a transformer, which can provide optimized operating conditions for each of several operating modes.

For this purpose, an additional winding is provided according to the invention, which can be included depending on the selected operating mode in the energy transfer or not. In this way, different voltage transmission ratios can be set in each case for a plurality of operating modes. As a result, the efficiency of such a three-port voltage converter can be increased.

The configuration of the individual windings of a

Transformer for such a three-port voltage transformer allows a very efficient, PCB-integrated design. This is advantageous, for example, for industrial applications since, from a production engineering point of view, integration of the inductive components into a printed circuit board can lead to a considerable cost reduction. The two transformer cores of the transformer are, for example, annular transformer cores. As a ring-shaped

Transformer core can, for example, a torroidförmige

Transformer core structure are considered. However, annular is not explicitly limited to circular or possibly oval. Rather, as a ring-shaped transformer core structure, it is also possible to consider a closed structure made up of a plurality of straightly extending transformer core elements which, for example, form a rectangular or square structure. For example, such an annular transformer core structure can be formed from a U-shaped transformer core and a yoke arranged above it. In addition, as annular transformer cores Of course, any other transformer core structures possible, which form a self-contained transformer core.

In one embodiment, the first transformer core and the second transformer core may include a common leg. In this

Case, the third secondary winding and the tertiary winding may be arranged on this common leg. In particular, a transformer core arrangement can be realized in this way, in which both

Transformer cores are realized as a common transformer core structure. This allows a particularly efficient and compact

Transformer assembly.

According to one embodiment, the windings of the first

Secondary winding, the second secondary winding and the third

Secondary winding be arranged komplanar. In addition, the

Tertiary winding may also be arranged as a coplanar winding. Under a coplanar arrangement of the windings is to be understood that all turns of a winding, for example, all turns of

Secondary windings are located in a common plane. If both the turns of the secondary winding and the turns of the tertiary winding are disposed coplanar, then the turns of the secondary winding can be arranged in a plane parallel to the plane in which the turns of the tertiary winding are located. In particular, in this case, the turns of the secondary winding and the turns of the tertiary winding can be arranged at least approximately congruent. Such a coplanar arrangement allows for increased efficiency of the transformer. In particular, by a coplanar arrangement, a homogeneous current distribution within the

Windings are achieved, which thus also leads to lower line losses.

In one embodiment, the coplanar windings are disposed on a printed circuit board substrate. In particular, the transformer may comprise a printed circuit board substrate having two opposite sides. On one of these pages, for example, the turns of the first secondary winding, the second secondary winding and the third Be arranged secondary winding. Furthermore, the windings of the

Tertiärwicklung on the other, that is, the opposite side of the printed circuit board substrate to be arranged. The turns of each

Windings may for example be designed as a printed circuit trace structure.

According to one embodiment, the turns of the first primary winding and the second primary winding are arranged coplanar. In particular, the turns of the first and second primary windings on a

PCB substrate to be arranged. In this case also the

Windings of the first and second primary windings are designed as printed circuit traces on a printed circuit board substrate. For example, the coplanar windings of the primary winding, the secondary winding and the tertiary winding can be arranged at least approximately congruent in different planes.

According to one embodiment, the tertiary winding comprises exactly one turn. In this way, a minimum number of turns for both the tertiary winding and thus corresponding to the primary and

Secondary windings possible.

According to one embodiment, the first transformer core and / or the second transformer core comprise at least one discrete air gap.

In particular, a transformer core, which represents the combination of the first and second transformer core, may also have a discrete air gap.

Alternatively, it is also possible to realize the first and / or second transformer core or a combination of first and second transformer core made of a material with ferromagnetic powder particles. such

Ferromagnetic powder particle transformer cores are also referred to as "powder cores" or cores with a distributed air gap. This makes it possible, for example, to influence the magnetic flux in the respective transformer cores.

The above embodiments and developments can, as far as appropriate, combine arbitrarily. Further refinements, developments and implementations of the invention also include not explicitly mentioned combinations of before or hereinafter with respect to

Embodiments described features of the invention. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic forms of the invention.

Brief description of the drawings

The present invention will be explained in more detail with reference to the embodiments given in the schematic figures of the drawings.

Showing:

Figure 1: a schematic representation of a transformer for a

Three-port voltage converter according to an embodiment;

FIG. 2 shows a schematic representation of a three-port voltage converter with a transformer according to an embodiment;

FIG. 3 shows a schematic representation of a three-port voltage converter with a transformer according to a further embodiment;

Figure 4: a schematic representation of a cross section through a

Three-port voltage converter according to an embodiment; Figure 5: a schematic representation of a plan view of a

coplanar arrangement of the secondary windings of a transformer according to an embodiment; and

FIG. 6 shows a schematic representation of a flow diagram on which a method for the transmission of electrical energy according to an embodiment is based.

Description of embodiments In the following description, like reference characters designate like or similar elements.

Figure 1 shows a schematic representation of a transformer 1, as it is based, for example, a three-port voltage converter according to one embodiment. The transformer 1 comprises a first transformer core 41 and a second transformer core 42. The two transformer cores 41 and 42 are, for example, annular transformer cores. In this case, a torroid-shaped transformer core structure can be regarded as an annular transformer core, for example. However, annular is not explicitly limited to circular or possibly oval. Rather, as a ring-shaped transformer core structure, it is also possible to consider a closed structure made up of a plurality of straightly extending transformer core elements which, for example, form a rectangular or square structure. For example, such an annular transformer core structure can be formed from a U-shaped transformer core and a yoke arranged above it. In addition, of course any other transformer core structures are possible as annular transformer cores, which form a self-contained transformer core.

The annular transformer cores 41 and 42 may optionally have one or more discrete air gaps. For example, one or more air gaps may be provided between a leg and a yoke of a transformer core 41, 42. In addition, the

Transformer cores 41 and 42 also include ferromagnetic powder particles.

Transformer cores with ferromagnetic powder particles are also referred to as so-called powder cores or as cores with a distributed air gap. This makes it possible, for example, to influence the magnetic flux in the respective transformer cores 41, 42.

The transformer 1 comprises six windings 11, 12, 21, 22, 23, 31. The first primary winding 11 and the second primary winding 12 are a first

Assigned voltage system. The first secondary winding 21 and the second secondary winding 22 and the third secondary winding 23 are associated with a second voltage system. The tertiary winding 31 is a third one Assigned voltage system. The first primary winding 11 is disposed on a first transformer core 41, that is, the first primary winding 11 is wound around the first transformer core 41 at a predetermined area. The second primary winding 12 is arranged on the second transformer core 42. The first primary winding 11 and the second primary winding 12 may be the same or at least approximately the same.

The first secondary winding 21 is disposed on the first transformer core 41, and the second secondary winding 22 is on the second

Transformer core 42 arranged. The first secondary winding 21 and the second

Secondary winding 22 may be formed at least approximately the same and in particular have an equal number of turns. Furthermore, a third secondary winding 23 is provided which is connected both to the first

Transformer core 41 and on the second transformer core 42 is arranged. In other words, the third secondary winding 23 encloses both the first transformer core 41 and the second transformer core 42 at a predetermined area. The first secondary winding 21, the second secondary winding 22, and the third secondary winding 23 each have a first terminal 211, 221, 231 on, which are electrically connected to each other at a node K. In addition, the first

Secondary winding 21, the second secondary winding 22 and the third

Secondary winding 23 each have a second terminal 212, 222 and 232.

Furthermore, the transformer 1 comprises a tertiary winding 31, which - analogous to the third secondary winding 23 - both on the first transformer core

41 as well as on the second transformer core 42 is arranged. In this way, in the tertiary winding 31, an electrical voltage can be induced, which is the sum of the magnetic fluxes in the two

Transformer cores 41 and 42 corresponds.

Figure 2 shows a schematic representation of a three-port voltage converter with a transformer 1 according to one embodiment. The transformer 1 in this embodiment corresponds largely to the transformer 1 of Figure 1. Therefore, the made in connection with Figure 1 apply

Embodiments also for the transformer 1 in Figure 2. The transformer 1 FIG. 2 differs from the previously described transformer in FIG. 1 only in that the first transformer core 41 and the second transformer core 42 are formed by a common transformer core. In particular, the two legs of the first transformer core 41 and the second transformer core 42, which of the third

Secondary winding 23 and the tertiary winding 31 are enclosed, combined into a single leg 40. Such a transformer core can be formed, for example, by an E-shaped structure with a yoke arranged above it. But there are others too

Possibilities for forming a combined transformer core according to Figure 2 possible.

For electrical energy transmission from the primary windings 11, 12 to the secondary windings 21, 22 and optionally to the tertiary winding 31, a first drive circuit 10 to the first primary winding 11, a first

Provide AC voltage Ul, and provide a second AC voltage U2 to the second primary winding 12. As a result, 42 magnetic fluxes are caused in the first transformer core 41 and the second transformer, which induce an electrical voltage in the first secondary winding 21 and the second secondary winding 22. Thus, a second drive circuit 20 can rectify the sum of these two induced voltages, that is, the electrical voltage between the second terminal 212 of the first secondary winding 21 and the second terminal 222 of the second secondary winding 22. The rectified voltage, for example, to charge an electrical energy storage such as

Example of the traction battery of an electric vehicle can be used.

The magnetic flux caused by the first primary winding 11 differs from the magnetic flux passing through the second

Primary winding 12 is caused, so also in the tertiary winding 31, an electrical voltage is induced by a connected

Rectifier circuit 30 can be rectified. This voltage can be used for example for charging an electrical energy storage, such as the energy storage of a low-voltage electrical system of a vehicle. FIG. 3 shows a schematic representation of a transformer 1 for a three-port voltage converter in a further operating mode. Of the

The transformer core 1 according to FIG. 3 is largely identical to the previously described transformer core from FIG. 2. For the transformer core according to FIG. 3, all previous embodiments apply. In the operating mode according to FIG. 3, the second drive circuit 20 can be connected between the second terminal 212 of the first secondary winding 21 and the second terminal 232 of the third secondary winding 23 apply an alternating electrical voltage U3. Furthermore, the second drive circuit 20 can apply an alternating electrical voltage U4 between the second terminal 222 of the second secondary winding 22 and the second terminal 232 of the third secondary winding 23. In particular, the two applied alternating voltages U3 and U4 can be the same or at least approximately the same. Flierdurch are caused magnetic fluxes in the transformer cores 41, 42, which induce an alternating electrical voltage in the tertiary winding 31. This induced AC voltage can be from the

Rectifier circuit 30 are rectified.

The windings of the first and second primary windings 11, 12, the first, second and third secondary windings 21, 22, 23 and the winding of

Tertiärwicklung 31, for example, each be executed coplanar.

Figure 4 shows a schematic representation of a cross section through a transformer 1 according to one embodiment. As can be seen, the turns of the first primary winding 11 and the windings of the second primary winding 12 can be arranged in a first plane.

For example, the turns of the first and second primary windings 11, 12 may be arranged as printed conductor tracks on a printed circuit board substrate 51. Similarly, the turns of the first, second and third secondary windings 21, 22, 23 may be arranged in a plane. These too

Windings can be realized as printed conductors on a printed circuit board substrate. For example, the windings of the first, second and third secondary windings 21, 22, 23 may be arranged on a further printed circuit board substrate 52. Alternatively, it is also possible that the turns of the first and second primary windings 11, 12 and the windings of the first, second and third secondary winding 21, 22, 23 are arranged on opposite sides of a common printed circuit board substrate.

Furthermore, the windings of the tertiary winding 31 can also be designed coplanar. These turns of the tertiary winding 31 can also be printed

Conductor tracks may be arranged on a printed circuit board substrate. For example, the tertiary winding 31 can be arranged between two printed circuit board substrates 51, 52, on which the primary and secondary windings are arranged. Of course, any other order for the primary, secondary and tertiary windings is possible.

5 shows a schematic representation of a plan view of a coplanar conductor track structure for the first, second and third secondary windings 21, 22, 23. The first secondary winding 21 encloses an outer leg of the first transformer core 41. Analogously, the second secondary winding encloses

22 an outer leg of the second transformer core 42. The third secondary winding 23 encloses a middle leg 40 which is associated with both the first and the second transformer core 41, 42. Below the coplanar arrangement of the secondary windings, for example, the tertiary winding 31 may be arranged. However, this is not shown in FIG. In one embodiment, the tertiary winding 31 can be at least approximately congruent with the dimensions of the

Secondary windings, in particular the third secondary winding 23 to be executed.

FIG. 6 shows a schematic representation of a flowchart as it can be carried out for a method for transmitting electrical energy by means of a previously described transformer 1. In a step S10, a first AC voltage U3 may be provided between a second terminal 212 of the first secondary winding 21 and a second terminal 232 of the third secondary winding. At the same time, a second alternating voltage U4 can be provided in step Sil between a second terminal 222 of the second secondary winding 22 and a second terminal 232 of the third secondary winding 23. An adjoining one induced voltage at the tertiary winding 31 can be rectified in step S12.

To summarize, the present invention relates to the transmission of electrical energy by means of a transformer for a three-port voltage converter.

For this purpose, an additional winding is provided in particular, which can be included in the energy transfer depending on the operating mode of the voltage transformer or not.

Claims

claims

A transformer (1) for a three-port voltage converter, comprising: a first annular transformer core (41); a second annular transformer core (42); a first primary winding (11) attached to the first transformer core

(41) is arranged; a second primary winding (12) attached to the second transformer core

(42) is arranged; a first secondary winding (21) disposed on the first transformer core (41) and including a first terminal (211) and a second terminal (212); a second secondary winding (22) connected to the second

Transformer core (42) is arranged, and which comprises a first terminal (221) and a second terminal (222); a third secondary winding (23) disposed on the first transformer core (41) and the second transformer core (42) and including a first terminal (231) and a second terminal (232); and a tertiary winding (31) which is arranged on the first transformer core (41) and the second transformer core (42), wherein in each case the first terminal (211) of the first secondary winding (21), the first terminal (221) of the second secondary winding ( 22) and the first Terminal (231) of the third secondary winding (23) at a common node (K) are electrically connected together.

2. Transformer (1) according to claim 1, wherein the first transformer core (41) and the two transformer core (42) has a common leg

(40) on which the third secondary winding (23) and the

Tertiary winding (31) are arranged.

The transformer (1) according to claim 1 or 2, wherein the turns of the first secondary winding (21), the second secondary winding (22) and the third secondary winding (23) are arranged coplanar, and wherein the tertiary winding (31) is a coplanar winding is arranged.

4. Transformer (1) according to claim 3, comprising a printed circuit board substrate (52), wherein the turns of the first secondary winding (21), the second

The secondary winding (22) and the third secondary winding (23) are arranged on a first side of the printed circuit board substrate (52), and the tertiary winding (31) is arranged on a second side of the printed circuit substrate (52) that corresponds to the first side of the printed circuit board substrate (52). is opposite.

5. Transformer (1) according to one of claims 1 to 4, wherein the windings of the first primary winding (11) and the second primary winding (12) are arranged komplanar.

6. Transformer (1) according to one of claims 1 to 5, wherein the

Tertiary winding (31) comprises a winding.

7. The transformer according to claim 1, wherein the first transformer core and / or the second transformer core comprise at least one discrete air gap, or as

Transformer cores are designed with a distributed air gap.

8. Three-port voltage transformer, with: a transformer (1) according to one of the preceding claims 1 to 7; a first drive circuit (10) which is designed to provide a first AC voltage (U1) to the first primary winding (11) and to provide a second AC voltage (U2) to the second primary winding (12); a second drive circuit (20) configured to rectify an AC voltage applied between the second terminal (212) of the first secondary winding (21) and the second terminal (222) of the second secondary winding (22) or between the second terminal (212) of the first secondary winding (21) and the second terminal (232) of the third secondary winding (23)

AC voltage (U3) and between the second terminal (222) of the second secondary winding (22) and the second terminal (232) of the third secondary winding (23) another

To provide AC voltage (U4); and a rectifier circuit (30) configured to rectify an AC voltage applied to the tertiary winding (31).

9. A method for transmitting electrical energy with a

Transformer (1) according to one of claims 1 to 7, comprising the steps:

Providing (S10) a first AC voltage (U3) between the second terminal (212) of the first secondary winding (21) and the second terminal (232) of the third secondary winding (23);

Providing (Sil) a second AC voltage (U4) between the second terminal (222) of the second secondary winding (22) and the second terminal (232) of the third secondary winding (23); and

Rectifying (S12) an alternating electrical voltage induced in the tertiary winding (31).