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The invention relates to a system with parallel LED drivers, corresponding AC-supplied lighting track and lighting system. In particular, the invention relates to a system comprising multiple LED drivers connected in parallel and supplied by a common supply voltage, each of said multiple LED drivers having a respective power factor correction, PFC, input stage with a corresponding control switch, an AC-supplied lighting track in which such a system is inserted, especially mechanically inserted, and a lighting system comprising such a system.
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Generally, LED drivers can be connected in parallel to increase the corresponding total output power. In this context, each of said LED drivers works on its own, which leads to the fact that an electromagnetic interference load on the overall system or mains supply, respectively, remains unchanged, and thus disadvantageously rather high.
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Accordingly, there is the object to provide a system comprising multiple LED drivers connected in parallel, an AC-supplied lighting track in which such a system is inserted, and a lighting system comprising such a system, wherein an electromagnetic interference load on the mains supply or power grid, respectively, can be reduced in a particularly efficient and reliable manner.
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This object is solved by the features of the first independent claim for a system comprising multiple LED drivers connected in parallel, the features of the second independent claim for an AC-supplied lighting track in which such a system is inserted, and the features of the third independent claim for a lighting system comprising such a system. The dependent claims contain further developments. Accordingly, the invention is described by the appended set of claims.
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According to a first aspect of the invention, it is provided a system comprising multiple LED drivers connected in parallel and supplied by a common supply voltage, each of said multiple LED drivers having a respective power factor correction, PFC, input stage with a corresponding control switch. In this context, respective switch-on times of the corresponding control switches of the PFC input stages are offset in time over an area of a switch-on cycle. In addition to this or as an alternative, the respective switch-on times of the corresponding control switches of the PFC input stages are de-synchronized.
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Advantageously, an electromagnetic interference load on the mains supply or the common supply voltage, respectively, can be reduced in a particularly efficient and reliable manner.
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According to an implementation form of the first aspect of the invention, the respective switch-on times of the corresponding control switches of the PFC input stages are offset in time by a period that is shorter than the respective switch-on time of at least one, preferably each, of the control switches.
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Advantageously, for instance, efficiency can be increased.
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According to a further implementation form of the first aspect of the invention, the respective time offset is less than 60 per cent of the switch-on cycle.
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Advantageously, for example, inefficiencies can be reduced.
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According to a further implementation form of the first aspect of the invention, with respect to the corresponding control switches, especially within the scope of manufacturing the system and/or the multiple LED drivers, different switch-on times are set and/or predefined.
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Advantageously, for instance, complexity can be reduced, thereby increasing efficiency.
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According to a further implementation form of the first aspect of the invention, the different switch-on times are set in relation to a phase position of the common supply voltage.
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Advantageously, for example, efficiency can further be increased.
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According to a further implementation form of the first aspect of the invention, at least two, preferably all, of the multiple LED drivers are configured to communicate with each other to coordinate the respective switch-on times of the corresponding control switches of the PFC input stages.
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Advantageously, for instance, de-synchronization of the multiple LED drivers can further be optimized.
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According to a further implementation form of the first aspect of the invention, the corresponding communication between the respective multiple LED drivers comprises or is a wireless communication.
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Advantageously, for example, the system can efficiently be decentralized.
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According to a further implementation form of the first aspect of the invention, at least one, preferably each, of the multiple LED drivers is configured to delay its respective switch-on time by a random value, especially be a self-determined pseudo-random value.
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Advantageously, for instance, complexity can be reduced, thereby increasing efficiency.
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According to a further implementation form of the first aspect of the invention, the respective switch-on time is delayed in relation to a phase position of the common supply voltage. Additionally or alternatively, the respective switch-on time is delayed based on a DALI address, a MAC address, a Matter address, a predefined setting, a predefined parameter, or any combination thereof, especially for the corresponding one of the multiple LED drivers (11a, 11b). Further additionally or further alternatively, the corresponding delay is configured via an interface, especially an NFC interface and/or a dimming interface.
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Advantageously, for example, efficiency can further be increased.
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According to a further implementation form of the first aspect of the invention, the respective switch-on times of the corresponding control switches of the PFC input stages are offset in time by a constant period or a substantially constant period.
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Advantageously, for instance, the different points in time of switching on the corresponding control switches can be equally distributed, especially thereby smoothing the current drawn from the common supply voltage or mains, respectively, in a particularly efficient manner.
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According to a further implementation form of the first aspect of the invention, at least one, preferably each, of the multiple LED drivers comprises an electromagnetic interference, EMI, filter.
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Advantageously, for example, complexity or size, respectively, of the EMI filter can be reduced, thereby increasing efficiency.
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According to a further implementation form of the first aspect of the invention, at least one, preferably each, of the multiple LED drivers comprises a radio frequency, RF, smoothing capacitor.
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Advantageously, for instance, value or size, respectively, of the RF smoothing capacitor can be reduced, thereby increasing efficiency.
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According to a second aspect of the invention, it is provided an AC-supplied lighting track in which a system according to the first aspect of the invention or any of its implementation forms, respectively, is inserted, especially mechanically inserted.
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Advantageously, an electromagnetic interference load on the mains supply or power grid, respectively, can be reduced in a particularly efficient and reliable manner.
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According to an implementation form of the second aspect of the invention, the multiple LED drivers are supplied by the corresponding AC supply of the AC-supplied lighting track as the common supply voltage.
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Advantageously, for instance, the multiple LED drivers can be distributed over the AC-supplied lighting track, especially in a decentralized manner.
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According to a third aspect of the invention, it is provided a lighting system comprising a system according to the first aspect of the invention or any of its implementation forms, respectively, and LED illuminants supplied by the multiple LED drivers.
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Advantageously, an electromagnetic interference load on the mains supply or power grid, respectively, can be reduced in a particularly efficient and reliable manner.
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Exemplary embodiments of the invention are now further explained with respect to the drawings by way of example only, and not for limitation. In the drawings:
- Fig. 1
- shows an exemplary embodiment of a system with parallel LED drivers in combination with an exemplary embodiment of a lighting system;
- Fig. 2
- shows an exemplary embodiment of a PFC input stage;
- Fig. 3
- shows exemplary time curves with respect to mains current resulting from a single LED driver or PFC input stage, respectively, drawing current from mains voltage; and
- Fig. 4
- shows exemplary time curves with respect to mains current resulting from two parallel LED drivers or PFC input stages, respectively, drawing current from mains voltage.
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With respect to Fig. 1, it is illustrated an exemplary embodiment of a system comprising multiple LED drivers, exemplarily two LED drivers 11a, 11b, connected in parallel and supplied by a common supply voltage 12, each of said multiple LED drivers or two LED drivers 11a, 11b, respectively, having a respective power factor correction, PFC, input stage with a corresponding control switch.
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In this context, respective switch-on times of the corresponding control switches of the PFC input stages are offset in time over an area of a switch-on cycle. In addition to this or as an alternative, the respective switch-on times of the corresponding control switches of the PFC input stages are de-synchronized.
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As it can further be seen from said Fig. 1, it is also depicted a lighting system 40 comprising said system 10 and a load 17 supplied by the multiple LED drivers or the two LED drivers 11a, 11b, respecgively1. Said load 17 can exemplarily be LED illuminants.
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For the sake of completeness, it is noted that the system 10 or the lighting system 40 can, especially mechanically, be inserted in an AC-supplied lighting track. In this context, the multiple LED drivers or the two LED drivers 11a, 11b, respectively, may be supplied by the corresponding AC supply of said AC-supplied lighting track as the common supply voltage 12.
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With respect to the above-mentioned PFC input stage, it is noted that an exemplary embodiment of such a PFC input stage 13 is illustrated by Fig. 2.
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In accordance with said Fig. 2, as already indicated above, the PFC input stage 13 comprises the control switch 14. Said control switch 14 may especially be configured to control corresponding current flow and/or to shape a corresponding input current, especially of the LED driver and/or of the PFC input stage, so that said input current is in phase with the common supply voltage 12 or mains voltage, respectively.
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As it can further be seen from Fig. 2, the PFC input stage 13 can further comprise a rectifier 18, especially a bridge rectifier, configured to rectify the common supply voltage 12 or mains voltage, respectively, for supplying the load 17 such as LED illuminants.
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As also depicted by said Fig. 2, it might be particularly advantageous if an electromagnetic interference, EMI, filter 15 is connected upstream of the rectifier 18 and/or a radio frequency, RF, smoothing capacitor 16 is connected downstream of the rectifier 18.
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Accordingly, it might be particularly advantageous if at least one, preferably each, of the multiple LED drivers or the two LED drivers 11a, 11b according to Fig. 1, respectively, comprises an EMI filter such as the EMI filter 15 according to Fig. 2.
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Furthermore, it might be particularly advantageous if at least one, preferably each, of the multiple LED drivers or the two LED drivers 11a, 11b according to Fig. 1, respectively, comprises a RF smoothing capacitor such as the RF smoothing capacitor 16 according to Fig. 2.
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Moreover, it might be particularly advantageous if at least one, preferably each, of the multiple LED drivers or the two LED drivers 11a, 11b according to Fig. 1, respectively, comprises a rectifier, especially a bridge rectifier, such as the rectifier 18 according to Fig. 2.
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Again, with respect to the system 10 or the lighting system 40, respectively, according to Fig. 1, it is noted that it might be particularly advantageous if the respective switch-on times of the corresponding control switches of the PFC input stages are offset in time by a period that is shorter than the respective switch-on time of at least one, preferably each, of the control switches.
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It is further noted that it might be particularly advantageous if the respective time offset is less than 60 per cent of the switch-on cycle.
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Moreover, it might be particularly advantageous if with respect to the corresponding control switches, especially within the scope of manufacturing the system 10 and/or the multiple LED drivers or the two LED drivers 11a, 11b, respectively, different switch-on times are set and/or predefined.
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In this context, it is noted that it might be particularly advantageous if the different switch-on times are set in relation to a phase position of the common supply voltage 12 or mains voltage, respectively.
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It is further noted that it might be particularly advantageous if at least two, preferably all, of the multiple LED drivers or the two LED drivers 11a, 11b, respectively, are configured to communicate with each other to coordinate the respective switch-on times of the corresponding control switches of the PFC input stages.
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In this context, it might be particularly advantageous if the corresponding communication between the respective multiple LED drivers or the two LED drivers 11a, 11b, respectively, comprises or is a wireless communication.
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Moreover, it is noted that it might be particularly advantageous if at least one, preferably each, of the multiple LED drivers or the two LED drivers 11a, 11b, respectively, is configured to delay its respective switch-on time by a random value, especially be a self-determined pseudo-random value.
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In this context, the respective switch-on time may preferably be delayed in relation to a phase position of the common supply voltage 12 or mains voltage, respectively. Additionally or alternatively, the respective switch-on time can be delayed based on a DALI address, a MAC address, a Matter address, a predefined setting, a predefined parameter, or any combination thereof, especially for the corresponding one of the multiple LED drivers or the two LED drivers 11a, 11b, respectively. Further additionally or further alternatively, the corresponding delay can be configured via an interface, especially an NFC interface and/or a dimming interface.
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It is further noted that it might be particularly advantageous if the respective switch-on times of the corresponding control switches of the PFC input stages are offset in time by a constant period or a substantially constant period.
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With respect to said term "substantially constant", it is noted that said term may especially understood as a corresponding deviation of not more than 15 per cent, preferably of not more than 10 per cent, more preferably of not more than 5 per cent, most preferably of not more than 3 per cent or of not more than 1 per cent.
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Now, with respect to Fig. 3, exemplary time curves are shown with respect to mains current resulting from a single LED driver or PFC input stage, respectively, drawing current from mains voltage.
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In this context, the curve showing mains voltage over time is equipped with reference sign 21. The curve depicting current consumption of the PFC input stage, such as the PFC input stage 13 according to Fig. 2, over time is equipped with reference sign 22. Furthermore, the curve illustrating current drawn from mains over time is equipped with reference sign 23. Said current drawn from mains may especially comprise or be a current smoothed by an EMI filter and/or a RF smoothing capacitor of the PFC input stage, such as the EMI filter 15 or the RF smoothing capacitor 16, respectively, according to Fig. 2.
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Finally, Fig. 4 shows exemplary time curves with respect to mains current resulting from two parallel LED drivers or PFC input stages, respectively, such as according to the system 10 of Fig. 1, drawing current from mains voltage or the common supply voltage 12, respectively.
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In this context, the curve showing mains voltage or the common supply voltage 12, respectively, over time is equipped with reference sign 31. The curve depicting current consumption of a first PFC input stage, such as the corresponding PFC input stage of the LED driver 11a according to Fig. 1, over time is equipped with reference sign 32a. By analogy, the curve depicting current consumption of a second PFC input stage, such as the corresponding PFC input stage of the LED driver 11b according to Fig. 1, over time is equipped with reference sign 32b. Furthermore, the curve illustrating current drawn from mains over time is equipped with reference sign 33. In contrast to the current drawn from mains according to Fig. 3, said current drawn from mains according to Fig. 4 is significantly smoother especially due to a de-synchronization of the first PFC input stage and the second PFC input stage or of the two LED drivers 11a, 11b according to Fig. 1, respectively.
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While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.
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Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.