DE102010045826A1 - Current distribution device for e.g. providing galvanically separated charge currents to battery units, has control unit attached to primary-sided winding, and secondary-sided windings galvanically separated on outer sides of core unit - Google Patents

Abstract

The device has a transformer device including a primary-sided winding (N1) and a set of secondary-sided windings (N2, N3) on a common E-shaped core unit (10), where the core unit includes a set of outer sides (14, 16) and a middle side. A control unit that controls current is attached to the primary-sided winding. The secondary-sided windings are galvanically separated from each other on the outer sides of the core unit. Primary- or secondary-sided units limit primary voltage at the primary-sided winding. The control unit corresponds to a primary side of a switching power supply.

Description

The present invention relates to a power distribution device having a transformer device, and to a use of such a current dividing device.

Generically, transformer devices having a primary winding (primary side winding) and a plurality of secondary windings (secondary side windings) are well known in the art. For general, generic prior art will be further explained on the 10 Reference is made, in which the primary-side winding N1 and two secondary-side windings N2, N3 are provided on a center leg (inner leg) of a core of ferromagnetic material. In an otherwise known manner, the magnetic coupling between these windings takes place through the forming, guided in the core magnetic circuit. To simplify the discussion, it should also be assumed here that the winding number of the windings is the same, ie N1 = N2 = N3.

In the case of primary-side voltage Ue (and primary current Ie flowing in winding N1), such a transformer design makes it possible for each of the secondary windings N2, N3 to supply the full, primary-side injected summation current (or the electric power fed in) on its own if the other secondary side outputs are unloaded; This is because, in an idealized view, the secondary-side outputs represent voltage sources.

However, if it is necessary because of the requirements of a (secondary side) wiring of such a transformer device, individually to limit the secondary side current I1 or I2, additional secondary-sided circuit complexity is necessary. Such a case occurs, for example, in the wiring with an electrical load, the secondary side instead of a power source requires a power source (specifically, for example, in the case of LED bulbs, which are typically connected in series with LED lighting strands). Here then a separate current-limiting or current-regulating circuit would be necessary for each (each provided at a secondary side output), which, in particular in the case of a plurality of outputs to be provided, can increase the circuit complexity considerably (there must be a separate current-limiting or current regulating circuit be provided).

The unpublished at the time of application of the present invention German patent application 10 2009 049 939 the Applicant illustrates a power distribution device, in which the secondary side is a power split to several channels to control driven in the manner described above, consumers. However, the thus implemented channels are each galvanically connected to each other, ie they all have the same reference potential and require at least one additional magnetic component in order to bring about the current distribution.

Object of the present invention is therefore to provide a power distribution device according to the preamble of the main claim, which provides a circuitically simple manner a plurality of secondary side current-limited or current-controlled outputs (channels), these channels should each be galvanically separated from each other (so far a allow mutual isolation of the channels).

The object is achieved by the current splitting device having the features of the main claim and the use of such a current splitting device according to independent claims 11, 12. Advantageous developments of the invention are described in the subclaims.

In an advantageous manner according to the invention, a current-splitting device with a transformer device is thus created as an essential functional unit, wherein the functional device has a primary-side winding and a plurality of secondary-side windings which are formed on a common core unit (which has a plurality of outer legs and a center leg). According to the invention, the primary-side winding is assigned (upstream) a drive unit, which on the primary side causes a current control (also including a current limitation). By providing the secondary-side windings on the outer legs of the core unit, a galvanic separation of the secondary-side windings from each other is made possible. Furthermore, in the current-controlled context, the means according to the invention for limiting a primary voltage, which are provided on the primary or secondary sides, ensure that the voltage at this open output does not rise uncontrollably on the secondary side with an open output of a winding (ie no current flow).

A power split device realized in this way thus has the advantage that the intended secondary-side and multi-channel current control can only be realized by the (individual) primary-side drive unit, with the corresponding hardware or circuit-technical advantages. Advantageously and preferably even a power split device can be realized, which secondary side no (additional or separate) current control or current limiting needed, so that especially in multi-channel systems considerable circuitry simplifications and hardware savings can be realized.

Within the scope of preferred embodiments of the invention, it is possible, for example in the manner of a primary-side configuration of a switched-mode power supply, to use different topologies enabling the current regulation functionality, for example to realize the drive unit as a push-pull converter circuit, as a resonant converter circuit or as a single-ended flux converter circuit. It is also possible, in the realization of a push-pull converter topology in M-circuit to provide the primary winding with a center tap. Comparable configurations are also possible on the secondary side, for example with the aim of realizing a two-way rectification.

According to a preferred embodiment, the inventive means for limiting the primary voltage are realized on the primary side, wherein, for example in the form of the mentioned topologies, the drive unit assumes this functionality. Alternatively and within the scope of further preferred embodiments of the invention, on the other hand, it is also possible to realize the means for limiting the primary voltage on the secondary side. This is done within the scope of the preferred developments by short-circuiting means, in particular by a short-circuit switch assigned to each secondary-side winding, which then enables current flow in the respective secondary-side branch (by a correspondingly limited short-circuit), again with the advantageous result that one each other Secondary branch (output) remains unaffected.

To optimize the magnetic flux guidance in the core unit, it has been found within the scope of preferred embodiments of the invention to design the core unit with its outer limbs and the center leg geometrically such that a sum of the cross-sectional areas of the outer limb corresponds to a cross-sectional area of the central limb provided with the primary-side winding ,

A particularly preferred embodiment of the invention, which is advantageous for large-scale production, also provides for the core unit to be designed in planar technology for interaction with at least one printed circuit board carrying the (primary-side and secondary-side) winding (s). Such a core unit advantageously has a surface section which is plan-shaped corresponding to the plan cooperation with the printed circuit board and from which at least one projection extends in one piece, which can realize the center leg or one of the outer legs; In a preferred development then all the legs are realized in the form of such one-piece elevations of the surface portion. In a first preferred embodiment, the plurality of secondary windings 2, so that a core unit with three legs (two outer legs and a center leg) allows the realization of such a variant. In the context of the invention, the plurality of secondary-side windings may also be greater than 2, in which case either by the provision of a plurality of transformer devices (which each have about two secondary-side windings and are connected in series on the primary side), such a total number of secondary-side windings can be achieved. Alternatively, with a transformer device which forms more than two outer limbs of the core unit, a plurality of secondary windings greater than 2 can be realized, wherein in particular the above-described planar technology with a number of legs corresponding elevations or projections is particularly favorable for the realization of such a development ,

The present invention is to be used particularly advantageously in connection with applications which have a plurality of separately provided, current-controlled or current-limited branches. This is the case, for example, in the field of illumination technology already mentioned above, where the present invention is favorably suitable for use, in that respective secondary-side windings (outputs) are assigned a light-emitting diode strand having a plurality of LEDs.

The present invention can also be used particularly advantageously in the provision of galvanically separated charging currents for a plurality of battery units respectively associated with the secondary-side windings (and thus separate from each other). Like. Charging current receivers.

However, the present invention is not limited to these uses or Einsetzfälle, but the present invention is suitable for any application in which a plurality of consumers - must be provided - each electrically isolated from each other - each with a current-limited or current-controlled signal, and in particular the additional effort of respective additional current limiter or control circuits for a particular branch to be avoided.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings; these show in

1 FIG. 3 is a schematic diagram of a three-winding transformer core to illustrate the basic principle of a first embodiment of the invention; FIG.

2 FIG. 3 is a schematic cross-sectional view of the device for clarifying a winding sense of the windings N1, N2, N3; FIG.

3 : an equivalent circuit diagram with the device 1 .

4 FIG. 2 is a schematic diagram illustrating the functionality of the embodiment of FIG 1 with symbolically and for explaining the principle of invention divided middle leg (inner leg);

5 : one according to the symbolic division of 4 drawn modification of 1 ;

6 a perspective view of a suitable embodiment of the invention in planar design of the core unit according to a second embodiment of the invention;

7 FIG. 2: a schematic representation of the winding of the core unit of FIG 6 for the realization of a transformer unit of the first embodiment of 1 ;

8th a third embodiment of the invention based on the core unit of 6 and a winding schematically shown with a primary winding and four galvanically isolated secondary side windings;

9 FIG. 4 is an equivalent circuit diagram of the third embodiment according to FIG 8th and

10 : A schematic representation of an wound with three windings E-transformer core to illustrate a belonging to the prior art and generic type transformer unit.

For the realization according to the invention of a current supplied by a primary-side (regulated) source by means of a transformer unit into a plurality of channels (each of which is galvanically separated from one another) 1 a schematic view of the basic functionality. An otherwise known E-core unit 10 points to her middle thigh (inner thigh) 12 the primary-side winding N1, which on the input side has a terminal voltage Ue adjacent and receives (regulated or not limited by a not shown, causing a current control drive unit) current Ie. This drive circuit is configured analogously to the primary side of a switched-mode power supply and, in the exemplary embodiment shown, forms the only hardware required for controlling the current of the secondary windings N2, N3 (or the currents I2 and I3 flowing therein). The secondary windings N2, N3 sit, as in the 1 shown on both sides of the middle leg formed outer legs 14 respectively. 16 the core unit 10 ,

In a manner not shown in detail, the secondary windings N2, N3 each feed a load (with a rectifier with filter capacitor, not shown, typically being provided on the secondary side).

By means of such an embodiment, it is advantageously achieved within the scope of the invention that both outputs (the secondary-side windings N2, N3) also form individually decoupled current sources during the current supply on the primary side. In this case, the output current of a secondary winding can be adjusted via the respective transmission ratio to the primary winding. By way of example, the example shown applies to the exemplary embodiment shown 1 the following relationships: N2 = N3 = 2 × N1 I1 = I2 = Ie / 2 Ue = U1 / 2 + U2 / 2.

Are, as in the example of 1 shown, N2 and N3 equal, thus their output currents are equal. It applies in the generalization: I1 = Ie × N1 / N2 and I2 = Ie × N1 / N3.

Transformed, the two secondary-side currents (output currents) have the following relationship to one another: I1 / I2 = N3 / N2.

As mentioned, two output circuits with output currents fixed on the secondary side are achieved by the primary-side current supply.

For further illustration of the voltage conditions at the windings as well as the winding configuration becomes the core unit 10 of the 1 split longitudinally in half, as in 4 in turn (in turn, according to the winding sense of 2 which is considered primary winding N1).

A magnetic flux Phi I generated in the (shown divided) inner inner leg of the input voltage Ue in N1 divides in two with the same cross-sectional area of the two halves equal parts, Phi Ia and Phi Ib, on. Due to the common winding (which means the same number of turns for each inner leg), only half the input voltage is applied to the winding at each core half; Thus, a partial winding with the same number of turns as originally N1 can be assumed on each core half. The corresponding equivalent representation of 5 clarifies this approach; the equivalent circuit diagram of 3 shows that from the total transformer device of the 5 resulting configuration. Effective for a particular, by dividing the 3 reached branches is therefore only half of the winding N1.

In the context of the present invention, with primary-side current regulation and therefore secondary-side action as current sources, the output current (I1, I2) causes a voltage U1 or U2 at its respective load. These output voltages are transformed to the input according to the following contexts: Ue1 = U1 × N1a / N2 and Ue2 = U2 × N1b / N3.

Since, as stated above, N1a = N1 and in the case of a series connection Ue = Ue1 + Ue2, then: Ue = N1 × (U1 / N2 + U2 / N3).

For the dimensioning of the winding N1, the maximum occurring voltage Ue, the operating frequency, a magnetic controllability of the core material and a geometry of the core unit must be taken into account. N2 and N3 then result from the desired current ratios, as stated above.

In the context of preferred developments, the core geometry is preferably to be designed such that the sum of the cross-sectional areas of all outer legs should correspond to the cross-sectional area of the inner leg; This can be achieved with commercially available E cores.

The present invention advantageously achieves that, in the case of a short-circuited output, the current in the relevant secondary-side branch does not increase if the primary-side supply current does not change. In contrast, however, in the embodiment of the 1 halve the voltage Ue on the primary side, which means that only half (output) power is converted. Current and voltage at the non-shorted output remain unchanged.

Has, as further development provided in the context of the invention, the primary side of the transformer unit feeding drive circuit on an output voltage limit, it turns in the case of an open output to this in the example of 1 twice the input voltage (while the voltage across the other output drops to 0 volts). This would result in current not flowing in any of the outputs; On the primary side, on the other hand, only the magnetizing current caused by the applied voltage flows. If, on the other hand, such a primary-side voltage limitation is missing, this must be done directly at the open output, whereby a short-circuit switch (so-called crowbar) is advantageously provided for each output-side branch, since the current advantageously continues to flow after activation (and causing a short circuit for a respective branch) leaves, with which the other output remains unaffected.

In order to realize an embodiment of the present invention with more than two secondary-side windings and thus more than two outputs, there is a first further developing solution variant therein, a plurality of transformer units (such as the embodiment of the 1 ) by connecting in series the primary windings of all transformer units. Accordingly, the feeding drive circuit must provide the sum voltage of all the transformer units. An output current of an output n still behaves to the input current Ie in the primary-side series connection as indicated above, namely In = Ie × N1 / Nn.

For n outputs, this solution requires n / 2 transformer units (as an integer). If n is an odd number, an additional transformer would go to 10 (Prior art) only connected to a secondary winding for this odd output; however, its primary winding is then connected in series with the other primary windings, the output current being as indicated above.

On the output side, in the context of preferred embodiments of the invention, it is possible to connect two or more outputs to one another by parallel connection in order to achieve an increased, resulting output current. Would be in this sense, the secondary windings N2, N3 off 1 connected in parallel, a sum output current I1 results as follows: Ia = I1 + I2 = Ie × (N1 / N2 + N1 / N3).

For the voltage conditions on a transformer unit connected in this way, the following applies: Ue = Ua × (N1 / N2 + N1 / N3).

Also, two outputs can be used to increase the maximum output voltage in series However, for this it is imperative that the two ratios (and thus the respective currents) are the same. Accordingly must apply here: N1 / N2 = N1 / N3.

Accordingly, the conditions for a parallel and series connection of outputs are opposite to those in an associated with 10 described standard transformer. There, unconditionally output windings can be connected in series, only the current carrying capacity of the individual windings must be considered. When connected in parallel, however, the same transmission ratio is required.

Referring again to the equivalent circuit diagram of the transformer unit of 1 , as in 3 It should be noted that windings TR1-AA (N1a) and TRI-AB (N1b) together form winding N1 1 TR1-A is N2 and TR1-B is N3. It is once again made clear that the output voltages are transformed with their respective gear ratio to the primary side and can be considered as connected in series there. In the case of several transformer units for increasing the output channel number, it is also evident from this that all the primary windings, as stated above, must be connected in series; this is the only way to ensure that each output has its predetermined current through its transformation ratio (and by changing the current injected on the primary side all the output currents change in the same ratio).

Based on 6 a variant of a core unit is described, which both for the realization of the embodiment of 1 (with n = 2 secondary-side windings), and, in a further development, for realizing a third embodiment ( 8th . 9 ) can be used.

The core element of 6 From a suitable core material is preferably realized in one piece and consists of a surface portion 20 , from which, molded in one piece, edge-elevation portions 22 . 24 . 26 . 28 , in the illustrated embodiment, a cross-sectionally cylindrical extend. In the middle area of the hole section 20 is also another increase section 30 for forming a center leg portion for a primary winding.

So clarifies first, for the realization of the first embodiment of 1 like the primary winding N1 on the core section 30 can be applied, while the two secondary-side windings N2, N3 in the manner shown, the projections 22 . 24 respectively. 26 . 28 spread. In practical implementation, these windings are suitably realized with the help of (possibly layered provided) printed circuit boards, as otherwise known.

About the realization of 1 in addition, however, cf. 8th . 9 with the help of a transformer core unit in 6 shown type also realize a current splitter, which is the primary-side winding in the illustrated embodiment n equal to four secondary-side windings, each with one of the projections 22 to 28 formed as a core section, assigns. It would then set the current In in an output channel as follows: In = Ie × N1 / Nn, according to the equivalent circuit diagram of 9 for each of the outer thighs 1 to 4.

As before, N1 is the primary number of turns on the middle leg and Ie is the current fed to the primary winding. The resulting voltage across the primary winding Ue then results as follows: Ue = N1 × (U1 / N2 + U2 / N3 + ... + Un / Nn + 1); for here z. B. n = 4.

Again, this realization form again allows a further increase in the number of outputs by primary-side series connection of the primary windings.

The present invention is not limited to the described embodiments. Rather, as explained above, there are any possibilities for configuration and adaptation to the primary and secondary requirements, whereby the advantage of avoiding separate, channel-wise secondary flow controls can always be realized.

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

• DE 102009049939 [0005]

Claims (12)

A current dividing device comprising a transformer device having a primary-side winding (N1) and a plurality of secondary-side windings (N2, N3) on a common core unit having a plurality of outer legs and a center leg, in particular at least sectionally E-shaped. 10 ; 20 ), characterized in that the primary-side winding is associated with a current control causing drive unit, the secondary side windings galvanically separated from each other on the outer legs ( 14 . 16 ; 22 - 28 ) of the core unit are formed and are provided on the primary or secondary side means for limiting a primary voltage to the primary-side winding. Current distribution device according to claim 1, characterized in that the secondary-side windings are not assigned separately and / or additionally provided current control means on the secondary side. Current distribution device according to claim 1 or 2, characterized in that the drive unit is designed so that it corresponds to the primary side of a switched-mode power supply. A current divider according to any one of claims 1 to 3, characterized in that the drive unit is configured as a push-pull converter circuit, as a resonant converter circuit or as a single-ended flux converter circuit. Current distribution device according to one of claims 1 to 4, characterized in that the means for limiting the primary voltage on the primary side, in particular by the drive unit, are realized. Current distribution device according to one of claims 1 to 4, characterized in that the means for limiting the primary voltage on the secondary side by short-circuiting means, in particular by each secondary-side winding associated short-circuit switch, are realized. Current splitting device according to one of claims 1 to 6, characterized in that the core unit is formed so that the sum of the cross-sectional areas of the outer legs corresponds to a cross-sectional area of the central leg provided with the primary-side winding (N1). Current splitting device according to one of Claims 1 to 7, characterized in that the core unit has a surface section which is designed so as to co-operate with at least one printed circuit board carrying the windings ( 20 ), from which at least one of the middle leg and / or one of the outer leg realizing survey ( 22 - 30 ) integrally formed extends. A current splitting device according to any one of claims 1 to 8, characterized in that the plurality of secondary-side windings is larger than 2, the current-splitting device having more than one transformer device each having no more than two secondary-side windings. A current splitting device according to any one of claims 1 to 8, characterized in that the plurality of secondary-side windings is larger than 2, wherein the transformer device of the current-dividing device has a core unit constituting more than two outer legs. Use of the Stormaufteilungsvorrichtung according to one of claims 1 to 10 for providing galvanically isolated supply currents to each of the secondary-side windings associated lighting units, in particular in each case a plurality of LED having light-emitting strands. Use of the current dividing device according to one of claims 1 to 10 for the provision of galvanically separated charging currents for a plurality of battery units respectively associated with the secondary-side windings.

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