The present invention relates to a device for controlling a plurality of electrical consumers according to the preamble of the main claim. Electrical consumers may have LEDs in the form of strands in particular. On the other hand, the invention includes and claims the act of providing these electrical consumers in the form of electrical consumers which do not have semiconductor-based lamps, in particular no LEDs, and instead are implemented as batteries (in which case the present invention is then embodied to control a plurality of such batteries as a charging device) and additionally or alternatively, the electrical consumers have electric motors, or again alternatively, they may have a plurality of galvanic devices to which a constant electrical current is supplied.
With regard to the state of the art, reference should first be made to the LED technology.
In particular for the purpose of manufacturing intensely bright lights, (high-performance) LEDs in strand form are combined as a series connection, to then be able to deliver the cumulative light intensity (on a suitable carrier).
The need for achieving a uniform light output of each LED leads to the fact that they are arranged as a series connection in the manner described here; a typical voltage drop of approximately 3.2V with a white LED then results in voltages of approximately 32V being applied per strand in the arrangement illustrated in
However, component tolerances and other manufacturing-related deviations result in the fact that, in the absence of separate measures, parallel circuits of multiple strands will develop voltage differences, the result being an uneven current distribution among the individual strands. This leads to an irregular brightness of the respective LEDs in an advantageous manner and leads to disadvantages in terms of the lifetime of the lamps.
Accordingly, to achieve a uniform luminous efficiency of parallel-connected strands, each having a plurality of LED lamps, it is customary in the state of the art to connect a current regulator upstream from each strand to adjust and/or regulate the current (I1 in strand 1, I2 in strand 2 in
However, this is complicated because a separate current regulating unit is required for each strand, so that there is a demand for a simplified current regulation for a plurality of parallel strands of LED lamps provided in the form of a series connection, in particular in the field of large-scale manufacturing technology and/or consumer applications. Furthermore, this basic demand exists not only for the LED lamps, which are used only for the context of this problem but instead there is also such a demand for any consumers, typically those such as batteries (to be charged) which receive a constant (regulated) current, electric motors (in particular stepping motors) or galvanic systems. All these consumers as well as additional electrical consumers which are typically operated at a constant current are considered to be “electrical consumers” in the remaining text in the sense of this invention, wherein a preferred implementation form of the invention excludes semiconductor-based lamps, in particular LEDs, from the invention.
The object of the present invention is therefore to simplify a generic device for controlling a plurality of electrical consumers, in particular to reduce the structural complexity and/or hardware complexity, while at the same time providing a circuit which makes it possible to apply a current to the plurality of electrical consumers and to do so in an energy-efficient manner with a minimal power loss.
This object is achieved by a device for controlling a plurality of electrical consumers to which a constant control current is applied at control nodes. A transformer unit to which a regulated and/or constant current having a predetermined frequency is applied at the input end comprises at least one first and a second winding at the output end which have a common tap, a first circuit branch forming a first control node for a first electrical consumer is associated with the first winding, and a second circuit branch forming a second control node for a second electrical consumer is associated with the second winding. Furthermore, the first and the second circuit branch each have a magnetically interacting pair of reactors which are wound in opposite directions relative to each other, and a first reactor of said pair is connected to the first control node via rectifying means, while a second reactor of the same pair is connected to the second control node via rectifying means. The reactors that are connected to one of the control nodes are wound in opposite directions. The pairs of reactors are magnetically coupled, in particular having a common reactor core.
It is advantageously provided according to the invention that the total current which is kept constant and/or regulated and applied at the primary side is divided between two single individual currents at the secondary side of a main transformer (transformer unit and/or upstream device), it is preferable to provide for the division to be into equal individual currents on the secondary side through suitable identical design of the number of windings (winding numbers) of the windings on the secondary side, such that by adjusting the transmission ratio, a different adjustment may also be made.
According to the invention, a pair of chokes in the manner of a current transformer is now provided in each of the circuit branches on the secondary side, said pair consisting of oppositely wound chokes, which cooperate magnetically with one another (these chokes being provided on a common choke core, for example). Rectifier means, e.g., a diode for half-wave rectification, are then connected downstream from these choke coils in the direction of the first and/or second control nodes for the electrical consumers (
Since the choke pairs are also magnetically linked to one another, for example, (all of them) also being provided on the same choke core, it is advantageously achieved through such a device that each choke pair in the manner of a current converter divides the current for the half-waves (such that in the preferred case of the same number of windings, this ratio amounts to 1:1, whereas with different numbers of windings, the currents are inversely proportional to the transmission ratio in the choke pair).
The antipole design (i.e., the opposite windings of the individual chokes of a choke pair on a common core) advantageously results in the magnetic fluxes of the windings canceling one another out via the signal characteristic. With regard to the intended current regulation for a plurality of electrical consumers, for example, for controlling the control nodes CH1 and/or CH2 (
Accordingly, for implementation of the invention, a respective choke pair is to be designed and embodied with a respective absolute number of windings per coil according to a maximally occurring voltage difference between the strands and/or a desired maximal deflection of the core (taking into account its geometry).
In the further embodiment according to the invention, this even makes it possible for a control node (and/or a respective electrical consumer) to be short-circuitable by switching a short-circuit to ground (the current thereby increases only by its high-frequency component, which would otherwise be short-circuited by a respective filter capacitor. However, in such a case, the voltage supplied by the main transformer would be only half as great, so then only half the power would be consumed, based on the output current).
It is also advantageous that the principle according to the invention is not limited to providing a choke pair for each circuit branch and/or for each control node. Instead the output signal of a choke pair can be used according to the refinement and in the manner of a cascade to control two additional choke pairs in a suitable manner in turn so that in this way the number of control nodes to be controlled (and also the electrical consumers provided at these control nodes) is increased accordingly. As a result, n electrical consumers may each receive a constant current (and/or an ideally equalized) control current with n−1 divider transformers (wherein such a divider transformer provides two choke pairs on one common core).
As a variant to this cascaded embodiment of the invention, it is provided according to the invention (and has also been claimed independently) to provide an embodiment in the manner of a paired coupling of neighboring channels for the respective control nodes, in which a first choke of a first choke arrangement is connected downstream from the first winding of the transformer unit on the secondary side, this embodiment being connected to the first of the control nodes via rectifying means, and a third choke is connected downstream from the first choke arrangement, which is connected to the second of the control nodes via rectifier means. However, a second choke of the first choke arrangement is connected downstream from the second winding of the transformer unit on the secondary side and is connected to the first of the control nodes via rectifier means, and a fourth choke is connected downstream from the first choke arrangement and is connected to the second of the control nodes via rectifier means. According to the invention, an oppositely wound choke of a second choke arrangement is connected upstream from the second and fourth chokes, such that this second choke arrangement is connected to the two individual chokes between the first and/or second winding on the secondary side and the first choke arrangement. The chokes of the second choke arrangement are advantageously wound in opposite directions from one another according to the invention, likewise with the chokes of the first choke arrangement which are connected to a respective one of the control nodes being wound in opposite directions from one another (i.e., for example, the first choke and the second choke of the first choke arrangement, which are connected to the first control node). In addition, the chokes of the respective choke arrangements are also advantageously interconnected magnetically according to the invention, especially advantageously being provided on a common choke core.
In an inventive refinement of this variant of the invention, it is also possible to galvanically separate the respective control nodes (and/or the respective circuit branches, i.e., chokes of the first and/or second choke arrangements connected upstream from the control node). To this end, the transformer unit has a plurality of first and second windings on the secondary side, each being assigned to these branches and separated from one another and/or insulated from one another.
According to an especially favorable variant of the invention, for which protection is claimed independently, only one winding is present on the secondary side of the main transformer. Here again, providing a choke pair (magnetically linked together) in the manner described here also leads to the desired result, but with such a simplified (and asymmetrical) topology, one must ensure that the magnetization of the core occurring due to voltage differences is suitably demagnetized. Within the scope of this aspect of the invention, it is therefore advantageous to provide a demagnetizing unit with an auxiliary winding, which leads to a demagnetization potential, more preferably with the help of a (bridge) rectifier or this auxiliary winding with a center tap and two-way rectification, which thus causes the demagnetization of the core; in the exemplary embodiment described above, this was accomplished through the alternating half-waves in a normal-mode configuration and/or a center tap of the secondary winding.
Within the scope of the invention, it is preferable to implement the plurality of electrical consumers according to the invention not as LEDs, but instead to provide as electrical consumers only those consumers which do not have any semiconductor-based lamps, in particular no LEDs. It is especially preferred according to the invention to provide a plurality of (rechargeable) batteries as the plurality of electrical consumers, such that in this case the device according to the invention may be implemented as a charger. Alternatively, it is provided within the scope of preferred implementations of the invention to provide the plurality of electrical consumers in the form of a plurality of (electric) motors, in particular as stepping motors, which receive a constant current in the manner according to the invention. Furthermore, according to the invention, it is provided within the scope of preferred further embodiments of the invention that the plurality of electrical consumers is to be embodied as devices for galvanics and/or galvanic treatment of workpieces which receive the constant current in the manner according to the invention.
Additional advantages, features and details of the invention are derived from the following description of preferred exemplary embodiments as well as on the basis of the drawings, which show:
As further illustrated by the diagram in
Similarly and symmetrically with the first choke pair 20, the individual chokes 28, 30 of the second choke pair 22 lead over rectifier diodes (rectifier means) 34, 38 to the control nodes CH1 and/or CH2. It can be seen from the diagram in
During operation, the device shown here is supplied with a regulated and/or constant primary current on the primary side (in the manner of a conventional upstream device), such that this primary current then flows alternately in the secondary windings 12, 14 and/or in the branches 16 and 18 thus formed, depending on which half-wave is prevailing. The respective choke pairs 20 and/or 22 then act in the manner of a current transformer, such that the current in branch 16 is divided among the chokes 24, 26 (at an assumed winding ratio of 1:1). The magnetic fluxes of the windings cancel one another due to the opposing polarity. A similar situation applies to choke pair 22 in branch 18. It is advantageously found that although a voltage difference from CH1 to CH2 (each relative on ground) produces magnetization of the core, this is compensated and/or canceled with a subsequent repolarized half-wave.
In the exemplary embodiment shown here of a frequency of the applied current in the range between approximately 100 and 200 kHz (a range between 30 and 500 kHz is conceivable) and a maximum voltage at CH1 and/or CH2 in the range between approximately 40 and 50V (usually corresponding to 10 to 15 LEDs per strand), the chokes 24 to 30 have typical winding numbers from a few up to hundreds. Filter capacitors 40 and/or 42 are within the range of 1 μF to 10 mF.
In a refinement of the exemplary embodiment of
Then a clocked and/or periodic and/or modulated control of the gate terminal 52, for example, permits dimming of the LED strand connected at CH2, in that a short-circuit to ground takes place in accordance with the “on” time of the FET 50, and this portion of the current, which is tapped off to ground, is no longer available for the CH2.
The transistor 50 also permits voltage regulation, e.g., by the fact that the transistor 50 influences the charging and/or discharging performance of the capacitor 42 (for example, between two control values) through its switching behavior. If the modulation and/or an on:off pulse duty factor at the switching input 52 of the transistor 50 is/are altered, the strand current (I2 to CH2 here) can be adjusted suitably between 0 and 100% preselected rated value. The current in the other strand (CH2) remains unchanged in this configuration as long as the current supplied by the main transformer 10 remains constant.
If in a variation of the principle of
Additional choke pairs 60, 62, 64, 66 are provided here, such that the choke pairs 20, 22 sit on a common core (in continuation of the exemplary embodiment of
If the choke pairs 20, 22 as well as 60, 62 and 64, 66 are each interpreted as divider transformers, then a current regulation for a total of four strands and/or control nodes can be implemented with a total number of three divider transformers, or an implementation of n strands by n−1 divider transformers in generalized form.
The principle shown here is possible with any normal-mode main converter circuits including half bridge, full bridge, resonant converter, M circuit, etc.
For example, if the respective diodes are reversed in polarity as an example of an output, then a negative output voltage is applied at the corresponding control node and/or a negative output current flows. This current corresponds in amount to the positive current and can be adjusted as described above by stipulating corresponding transmission ratios. For example, if the polarity of the diodes (70, 72) is reversed for the control node CH4 (
A current flows here through the upper winding (64), then the same current also flows through the lower winding of the pair (66), but in the opposite direction, for example, during the positive half-wave. Since these two windings have the same direction of winding but the currents are now opposite from one another, the principle described above is applicable. In the preceding divider stage (windings 20 and/or 22), the magnetic fluxes are added up and the windings 20 (lower winding) and 22 (lower winding), the direction of winding and the currents are in opposition and advantageously create the balance with the current in the winding 20 (above) according to the invention.
It follows that the absolute current division is maintained in the manner provided according to the invention again in this case of an output with a reversed polarity.
However, since there is a magnetization of the choke core (which would not be demagnetized in the half-wave of the opposite polarity, as with the normal-mode circuit described above) due to the single-cycle implementation of
The demagnetizing winding 86 may also be fed back to the primary side (with appropriate insulation).
The principle illustrated in
In concrete terms the transformer unit 10 again has two windings 12 and/or 14 on the secondary side which have a shared tap to ground GND.
As also shown from the diagram in
With regard to a further choke arrangement consisting of choke pairs 74 (for the third control node CH3) and 76 (for the fourth control node CH4) the exemplary embodiment of
The respective choke arrangements 70, 72 and 74, 76 as well as 80, 82 have a transmission ratio of 1:1. As a result a current I1 to the first control node CH1 is equal to the current I2 to the second control node CH2. The additional choke arrangements are designed accordingly, such that the choke arrangement (transformer) 80, 82 ensures that I2=I3, and the choke arrangement 74, 76 (transformer) ensures that I3=I4 accordingly.
As a result, it holds that I1=I2=I3=I4, so that each output current in one of the control nodes CHi (i=1 to 4) has a quarter of the value predetermined by the main transformer 10 (and/or its control on the primary side).
The wiring diagram in
The circuit principle of the exemplary embodiment of
If an output signal (control node) has one current value that is different from the others, then the transmission ratio of the choke arrangements connected to the respective control node is to be adjusted, wherein the aforementioned rules are applicable. For example, if a different current value flows in the node CH2 in the circuit of
Within the context of the preferred refinements of the invention, it is also possible to combine the principles of the exemplary embodiment of
Due to this division of the main transformer 10 into a plurality of mutually insulated secondary windings, there is a magnetic decoupling of the four channels shown. A similar phase angle is to be ensured for each channel according to the allocation and design of the windings 12, 14 of
Number | Date | Country | Kind |
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10 2009 049 939 | Oct 2009 | DE | national |
10 2010 010 235 | Mar 2010 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2010/006354 | 10/19/2010 | WO | 00 | 6/7/2012 |
Publishing Document | Publishing Date | Country | Kind |
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WO2011/047818 | 4/28/2011 | WO | A |
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English translation of Chinese Office Action for 2010800578581, dated Nov. 28, 2013. |
Official action dated Jun. 6, 2012 for DE 10 2010 010 235.0. |
Number | Date | Country | |
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20120242267 A1 | Sep 2012 | US |