Abstract:
An operating device ( 1 ) for operating an illuminant ( 2 ) is proposed, having: an energy storage unit ( 3 ) for storing electrical energy, a charging circuit ( 4 ), requiring the supply of a mains voltage (Vin), for charging the energy storage unit ( 3 ) during a charging mode of operation, a driver circuit ( 7 ), supplied with power by means of the energy storage unit ( 3 ) during a storage mode of operation, for operating the illuminant ( 2 ), and a control unit ( 8 ) for activating the charging mode of operation or the storage mode of operation independently of the state of the mains voltage (Vin), particularly independently of the level of the mains voltage (Vin).

Description:
FIELD OF THE INVENTION 
     The invention relates to an operating device for operating at least one light-emitting means by means of an autonomous energy store and to a luminaire comprising such an operating device, to a method for operating or for controlling such an operating device, to an integrated circuit, to a computer software program product, and to a lighting system. 
     BACKGROUND 
     It is already known from the prior art to use also emergency lighting devices in addition to the luminaires to which a mains voltage is supplied. These emergency lighting devices are used in the event of failure of the mains supply in order to ensure a minimum level of illumination in areas in which luminaires to which mains voltage is supplied are installed. 
     Such emergency lighting devices are capable of monitoring the mains supply voltage and correspondingly establishing an emergency lighting operation as soon as, for example, the mains voltage is below a preset threshold value. Generally, in order to identify the state of the grid, a voltage which is representative of the mains voltage is measured. It is possible, for example, for the mains voltage to be measured directly via an input-side voltage divider. Given knowledge of an emergency state, in particular an excessively low supply voltage, the emergency state of the emergency lighting device is then activated, in which an internal battery or an internal rechargeable battery for supplying power to a lamp is switched on. 
     Secondly, there are grids in which different prices for the mains supply are demanded at different times. In particular, the current may have a more favorable tariff at night than during the day. In the case of some domestic appliances, the consumer may make use of this tariff system by virtue of switching on certain appliances at night. For example, it is possible to program washing machines or dishwashers such that they are automatically started at night. 
     Against the background of this prior art, the present invention is now based on the object of improving the operation of light-emitting means with a view to the differentiated tariff system for mains supply. 
     SUMMARY 
     The central concept of the invention now consists in that a luminaire comprises an energy store, from where the luminaire can be operated over a relatively long period of time in the same way as when it is operated on mains voltage. 
     During times in which an energy provider&#39;s demands increases prices for the supply, the luminaire can then be operated from the energy store, wherein the energy store is recharged during more favorable energy times. 
     In contrast to emergency lighting systems, therefore, the luminaire is then also operated from the energy store during these times of increased tariffs although the AC supply, in contrast to the emergency light case, has not broken down. 
     The energy supply from the store can be used in support of or in addition to the AC supply. 
     The operating device in the luminaire has either internal intelligence which switches the operating mode between AC supply/autonomous supply, or alternatively or in addition the signal in respect of whether the luminaire is now intended to be operated preferably from the autonomous energy supply or not can be communicated from outside either via a separate control line, for example bus line or wirelessly, or via an information item modulated onto the AC supply itself via a carrier frequency system or powerline communication (PLC). This operation clocking can in the meantime also be switched on by the user, for example, via switches, rotary actuators, etc. comparable to a time switch. 
     The operating device in the luminaire can itself also adaptively learn the durations during which the luminaire should preferably be operated by the autonomous energy supply, for example via the nature of the activation by the user (switch on/off operations), by brightness signals from a light sensor, etc. 
     For example, the operating circuit can also initiate recharging of the autonomous energy supply when a decision is made for nighttime power on the basis of the fact that the luminaire has already not been operated for a relatively long period of time. 
     For example, specially equipped highly capacitive capacitors, super capacitors or super caps can be used as energy store. Alternatively, batteries or rechargeable batteries can also be used. 
     The control circuit in the operating device also performs the control of the charging/discharging management for the energy store. 
     A preferred embodiment is the use of LEDs as light-emitting means since, in the case of these LEDs, owing to their typical operating voltages, the autonomous energy supply from a battery can be operated identically to the provision of a low-voltage bus voltage by the first stage of a converter. 
     In accordance with a first aspect of the present invention, therefore, an operating device for operating a light-emitting means is proposed, comprising
         an energy storage unit for storing electrical energy,   a charging circuit to which a mains voltage is to be supplied for charging the energy storage unit during a charging operating mode,   a driver circuit to which power is supplied by the energy storage unit during a storage operating mode for operating the light-emitting means, and   a control unit for activating the charging operating mode or the storage operating mode independently of the state of the mains voltage, in particular independently of the level of the mains voltage.       

     In accordance with a further aspect of the present invention, a method for operating a light-emitting means is proposed, comprising
         charging an energy storage unit by means of a charging circuit to which a mains voltage is supplied during a charging operating mode,   operating the light-emitting means by means of a driver circuit, to which power is supplied by the energy storage unit, during a storage operating mode,       

     wherein a control unit activates the charging operating mode or the storage operating mode independently of the state of the mains voltage, in particular independently of the level of the mains voltage. 
     In such an operating device or method, in the event of a mains supply with a high-tariff current or in the event of a high load phase or peak load phase of the supply grid, there can be switchover to the storage operating mode. In other words the storage operating mode can be performed during times in which the price for the mains supply and/or the load on the supply grid are comparatively high. 
     Preferably, in the event of a mains supply with a low tariff current or in the event of a weak load phase of the supply grid, there is a switchover to the charging operating mode. 
     Information items, for example, relating to the current tariff or the load of the supply grid can be communicated to the control unit. 
     The information items can be communicated via a PLC receiver via powerline communication, via a control line such as, for example, a digital bus line, via a user interface or via a sensor. 
     Preferably, provision can be made of a mains driver circuit for operating the light-emitting means during a mains operating mode, wherein, during the storage operating mode, the mains driver circuit is switched off. 
     In accordance with a further aspect of the present invention, a luminaire is proposed, comprising a light-emitting means and an above-described operating device for operating the light-emitting means. 
     The light-emitting means can preferably be a light-emitting diode. 
     In accordance with a further aspect of the present invention, an integrated circuit is proposed, in particular an ASIC, for implementing the above method. 
     In accordance with a further aspect of the present invention, a computer software program product is proposed, which supports the above method when it is run on a microcomputer. 
     In accordance with a further aspect of the present invention, a lighting system is proposed, said lighting system comprising a plurality of luminaires which each comprise a light-emitting means and an operating device for operating the light-emitting means, wherein, in the event of a mains supply with a high-tariff current or in the event of a high load phase or peak load phase of the supply grid, at least one light-emitting means of a luminaire is switched off. 
     In this case, a central unit can communicate the commands for switch off of the light-emitting means via a control line or via powerline communication via mains lines to the respective operating device. 
     At least one predetermined operating device automatically can switch off its light-emitting means if a high tariff current or a high load phase or peak load phase of the supply grid is identified. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages, features and properties of the present invention will now be explained with reference to the figures of the attached drawings. 
         FIG. 1  shows, schematically, an operating device and a system in accordance with the present invention. 
         FIG. 2  shows, schematically, a further exemplary embodiment of the present invention. 
         FIG. 3  shows a further embodiment of the invention. 
         FIG. 4  shows an embodiment of a lighting system in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The operating device according to the invention which is illustrated schematically in  FIG. 1  and is generally provided with the reference symbol  1  is intended for operating a light-emitting means  2  in the exemplary embodiment illustrated. A luminaire  6  comprises the operating device  1  and the light-emitting means  2 . The operating device  1  is connected on the input side to a power supply grid, which makes available a mains supply voltage Vin, and for this has a mains voltage input  11  which can be connected to mains lines  5 . The mains voltage can in this case be present as AC voltage, rectified AC voltage or DC voltage. 
     The operating device  1  furthermore has, as essential components, a charging circuit  4 , an energy storage unit  3  and a driver circuit  7  and a control unit  8 . The mains voltage Vin which is used for charging the energy storage unit  3  is supplied to the charging circuit  4  on the input side. The charging is performed during a charging operating mode. 
     The completely or only partially charged energy storage unit  3  supplies power to the driver circuit  7  in a storage operating mode, which driver circuit in turn operates the light-emitting means  2  in a known manner. The light-emitting means  2  can be connected to the driver circuit  7  via a supply output  13  of the operating device  1 . 
     A mains processing unit  22  and a mains driver circuit  23  are provided in parallel with the series circuit comprising the charging circuit  4 , the energy storage unit  3  and the driver circuit  7 . The mains processing unit  22 , as is known, is used for processing the supplied mains voltage Vin by virtue of, for example, the voltage being rectified and/or smoothed or by virtue of active or passive power factor correction being implemented. The active power factor correction can be formed, for example, by a step-up converter or a flyback converter. 
     The processed voltage is then supplied to the mains driver circuit  23 , which supplies power to the light-emitting means  2 . The mains driver circuit  23  is controlled by the control unit  8 , as is known. The mains driver circuit  23  can be configured, for example, in the form of an inverter with a half-bridge circuit (not shown), wherein two switches of the half-bridge circuit which are connected in series and to which a DC voltage is supplied are clocked in opposition by the control unit  8  in order to provide a desired output voltage or a desired output power at the supply output  13 . 
     In addition to the storage operating mode, in which the light-emitting means  2  is supplied exclusively with the electrical energy stored in the energy storage unit  3 , a further operating mode is thus provided. That is to say, the light-emitting means  2  can be supplied with power in a mains operating mode by the mains driver circuit  23  via the mains voltage Vin. The driver circuit  7  and the mains driver circuit  23  can be exclusively switched on in the respective mode. Alternatively, in a hybrid operating mode, the control unit  8  can actuate the operating device  1  such that both the driver circuit  7  and the mains driver circuit  23  are active simultaneously and provide power for operating the light-emitting means  2 . 
       FIG. 2  shows a particular embodiment of part of the operating device  1  of the invention.  FIG. 2  does not show the mains processing unit  22  and the mains driver circuit  23 . In this case, the charging circuit  4  is formed by a so-called flyback converter, which comprises firstly a transformer T with a primary winding n 1  and a secondary winding n 2  and secondly a controllable switch S 1 . In a known manner, by corresponding alternate opening and closing of the switch S 1 , the energy made available by the mains supply voltage Vin can be transmitted to the secondary side of the flyback converter  4  and used for charging the energy storage unit  3 . The energy transmission in this case takes place in the open state of the switch S 1 , wherein in addition a diode D 1  is provided on the output side of the flyback converter  4  for this purpose. 
     The actuation of the controllable switch S 1  is performed by the control unit  8  of the operating device  1 , wherein the actuation in particular takes place in galvanically isolated fashion via an optocoupler  21 . In this case, the control unit  8  actuates the switch S 1  alternately. 
     The energy storage unit  3  is configured in the form of a battery or a rechargeable battery. Alternatively, the energy storage unit  3  can consist of one or more double-layer capacitors or super capacitors. Advantageously, provision is made for the control unit  8  to detect the current Ibat through the energy storage unit  3  and/or the voltage drop Ubat across the energy storage unit  3 . The current detection is performed in particular by a measuring shunt (not shown) connected in series with the energy storage unit  3 . 
     The driver circuit  7  in the form of a switching controller has a further controllable switch S 2 , an inductance L and a diode D 2 . By alternate actuation of the switch S 2  by the control unit  8 , a current or a power is thus made available to the light-emitting means  2 , via which current or power said light-emitting means is operated. The duty factor and/or the frequency at which the switch S 2  is actuated by the control unit  8  can in this case be varied in order to adjust the level of the current supplied to the light-emitting means and thus the power at which the light-emitting means is operated. In this way, it is possible to ensure that the light-emitting means can nevertheless be operated at a constant power even in the event of a fluctuating power of the energy storage unit. 
     The light-emitting means  2  shown in the embodiment in accordance with  FIG. 2  is a light-emitting diode or LED. The operating device  1  according to the invention can operate any type of light-emitting means, however, in particular gas discharge lamps or incandescent lamps. The supply output can be designed to supply one or more light-emitting means  2 . The driver circuit  7  can preferably be adapted corresponding to the light-emitting means  2  connected. 
       FIG. 3  shows a further embodiment of the invention. The light-emitting means  2  can be operated, according to the invention, by the autonomous energy storage unit  3  (storage operating mode) as soon as the price for the mains supply is high or as soon as it is above a threshold value. The use of the energy storage unit  3  is not only dependent on the electrical state of the mains lines  5  or the mains supply, as in the case of an emergency lighting device, for example. In the case of an emergency lighting device, an internal battery is switched on, for example, in the event of a power failure or in the event of a mains fault in order to ensure the supply of power to the light-emitting means. A mains fault in this sense can be, for example, an undervoltage, an overvoltage, a change in frequency or the occurrence of harmonics. 
     The control unit  8  controls the use of the energy storage unit  3 . The decision in respect of switching on or off the driver circuit  7  is performed on the basis of an information item which is representative of the price of the mains supply. 
     This information item is received by the control unit  8 , for example, via powerline communication (PLC). A corresponding high-frequency data transmission is performed via the mains line up to the mains voltage input  11  of the operating device. The mains voltage Vin is supplied to a PLC receiver  9 , which again demodulates the high-frequency modulation of the mains voltage. The demodulated information item is passed onto the control unit  8 , which makes a decision in respect of switching on the driver circuit  7  on the basis of this information item, in particular relating to the price of the mains supply. 
       FIG. 3  also shows that the control unit  8  can receive the information item also via a control line  10  in the form of a bus, for example. The operating device  1  is correspondingly provided with a control signal input  12  in the form of a digital bus interface, for example. Incoming control signals which are transmitted by an external control unit (not shown) are monitored by the control unit  8  and evaluated in respect of the use of the energy storage unit  3  and the driver circuit  7 . 
     A user can also communicate an item of information with respect to the price of the mains current directly via a user interface  14  and via a user interface input  18  to the control unit  8 . The user interface  14  can comprise operating elements such as a pushbutton  15 , a potentiometer  16  or a touchscreen  17 . The information item can also be communicated to the operating device  1  via a sensor  19  and a corresponding sensor input  20 , for example. 
     The information item relating to the current price can also be recorded in a data store  24 , in particular once this information item has been received by the control unit  8 . Preferably, it is also possible for the times at which low tariff current needs to be drawn to be stored in the data store  24  when the operating device is manufactured in the factory. 
     The PLC receiver  9 , the control signal input  12 , the user interface input  18  and the sensor input  20  can be used together in an operating device  1 . Alternatively, a subset of these four elements can also be provided. In particular, the operating device  1  can have only the PLC receiver  9 , only the control signal input  12 , only the user interface input  18  or only the sensor input  20  for communicating information items. 
     The information item communicated to the control unit  8  relates preferably to the present price for the mains supply, wherein this price can entail immediate switching-on of the driver circuit  7 . Alternatively, the information item can also, however, relate to an as yet invalid, future price or to a change in price. For example, the information item then consists of a price per unit energy and a time indication from when the provided price is valid. It is also conceivable for the time indication to determine the time until which a given price is valid. All of these information items can be stored in the data store  24 . 
     The information item on the basis of which the driver circuit  7  is switched on and off relates to the current price in the above-described exemplary embodiment. According to the invention, the actual current price or a value which is representative of the current price is communicated, wherein then the control unit  8  needs to decide whether, at this price, the storage operating mode (via the energy storage unit  3  and driver circuit  7 ) or the mains operating mode (by mains supply via the mains processing unit  22  and mains driver circuit  23 ) should rather be used for operating the light-emitting means. This decision is preferably made on the basis of experience-based values by virtue of the control unit  8  comparing previously received price indications stored in the data store  24  with the present indication. For example, when the present current price is above a mean value of the previous price indications, a switchover is performed to the storage operating mode. 
     Alternatively or in addition, it is not directly the current price but a more general information item relating to the tariff system that is communicated to the control unit  8 . Preferably, it is possible to communicate whether the supply via the mains line  5  corresponds to a high tariff current or a low tariff current. If a high tariff is present, the energy storage unit  3  and the driver circuit  7  are used corresponding to the storage operating mode. 
     Alternatively or in addition, it is also possible merely to communicate the time at which the high tariff current is valid. In the event of the occurrence of a high tariff current, there is a change to the storage operating mode. 
     In contrast, in the case of a low tariff current or in the case of a low current price, the light-emitting means  2  can be operated and supplied with power via the mains driver circuit  24  (mains operating mode). At the same time, a phase with a relatively low price can be used to charge the energy storage unit  3  (charging operating mode). This charging is performed by virtue of the charging circuit  4  to which mains voltage Vin is supplied being controlled correspondingly by the control unit  8 . 
     Alternatively or in addition, information items relating to the mains load, in particular how high the mains load is or whether a weak load phase or a high load phase or peak load phase is present, are communicated to the operating device  1 . In a peak load phase, there is preferably a changeover to the storage operating mode. In a weak load phase, there is switchover preferably to the mains operating mode for operating the light-emitting means  2  and to the charging operating mode for charging the energy storage unit  3 . 
     Alternatively or in addition, a command signal can be transmitted to the control unit  8 , for example via the PLC receiver  9  or via the control line  10 , which command signal automatically initiates the storage operating mode or the mains operating mode. Preferably, at the same time as the mains operating mode also the charging operating mode is started for charging the energy storage unit  3 . 
       FIG. 4  shows an embodiment of a lighting system in accordance with the present invention. 
     A plurality of luminaires  6   a ,  6   b ,  6   n  are provided in a lighting system  25 . This is firstly in order to meet the standards in respect of illuminance, glare reduction or brightness uniformity. Secondly, a plurality of luminaires also ensures the ceiling coverage which increases user comfort and ensures general acceptance of the lighting system  25 . It is not unconventional for both the first mentioned and the second mentioned requirements to be met to excess. 
     A luminaire  6   a ,  6   b ,  6   n  according to the invention comprising in each case one light-emitting means  2   a ,  2   b ,  2   n  and one operating device  1   a ,  1   b ,  1   n  according to the invention comprising a control unit  8   a ,  8   b ,  8   n  can be switched over to the storage operating mode, as described above, in the event of a high tariff current or in the event of a peak load phase of the supply grid. 
     Previously defined operating devices  1   a ,  1   b ,  1   n  can alternatively switch off their associated light-emitting means  2   a ,  2   b ,  2   n  as soon as a high tariff current or a peak load phase of the supply grid is identified. The previously defined operating devices  1   a ,  1   b ,  1   n  are preferably selected such that their assigned light-emitting means  2   a ,  2   b ,  2   n  can be switched off without the abovementioned requirements placed on the lighting system  25  being impaired. 
     Since, however, the requirements in terms of illumination can be met to excess, during times in which the mains supply has a very high price or in the case of mains supply with high tariff current or in the case of peak load conditions, the invention proposes reducing the illuminance of the lighting system  25  as a whole. For this, it is proposed to entirely disconnect one or a plurality of luminaires. That is to say that, instead of changing over to the storage operating mode, the light-emitting means of the respective operating device is not operated or is switched off. Thus, costs can be saved. 
     Preferably, a central unit  26  decides which light-emitting means  2   a ,  2   b ,  2   n  should be switched off. For this, the central unit  26  transmits corresponding commands via the control line  10 . Alternatively, the commands can be communicated via the mains line via powerline communication. 
     LIST OF REFERENCE SYMBOLS 
     
         
           1 ,  1   a ,  1   b ,  1   n  Operating device 
           2 ,  2   a ,  2   b ,  2   n  Light-emitting means 
           3  Energy storage unit 
           4  Charging circuit 
           5  Mains line with mains voltage Vin 
           6 ,  6   a ,  6   b ,  6   n  Luminaire 
           7  Driver circuit 
           8 ,  8   a ,  8   b ,  8   n  Control unit 
           9  PLC receiver 
           10  Control line 
           11  Mains voltage input 
           12  Control signal input 
           13  Supply output 
           14  User interface 
           15  Pushbutton 
           16  Potentiometer 
           17  Touchscreen 
           18  User interface input 
           19  Sensor 
           20  Sensor input 
           21  Optocoupler 
           22  Mains processing unit 
           23  Mains driver circuit 
           24  Data store 
           25  Lighting system 
           26  Central unit 
         D 1 , D 2  Diode 
         L Inductance 
         n 1  Primary winding 
         n 2  Secondary winding 
         S 1 , S 2  Switch 
         T Transformer