Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
  • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/36—Controlling
  • H05B41/38—Controlling the intensity of light
  • H05B41/39—Controlling the intensity of light continuously
  • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor

Definitions

• the invention relates to a device for providing an amount of power to a gas discharge lamp.
• the invention also relates to a system comprising a device, to a method, to a computer program product and to a medium. Examples of such a device are electronic ballasts, and examples of such a system are power supplies, and/or lights comprising gas discharge lamps.
• the computer program product may be used in a computer, a microcontroller, and analog and/or digital control circuitry etc. As a result, the device can be any kind of control device.
• a discharge bulb ballast has a control circuit that includes a turning point detecting unit for detecting a turning point at which a bulb voltage starts rising after switching on a discharge bulb.
• a power control unit carries out control in such a manner that the discharge bulb is supplied with first power.
• the turning point detecting unit detects that the voltage of the discharge bulb exceeds the turning point, the power control unit supplies the discharge bulb with second power less than the first power.
• a device for providing an amount of power to a gas discharge lamp, the device comprising a control circuit for controlling a supply circuit for supplying the power according to a power versus voltage graph, the power versus voltage graph defining a first state for supplying a first amount of power, the power versus voltage graph defining a second state for supplying a second amount of power, the first state ending at a boundary voltage value of a voltage signal and the second state starting at the boundary voltage value, the control circuit comprising a calculator for calculating the boundary voltage value as a function of a measured voltage value of the voltage signal that has been measured after a predefined time-interval from a cold start of the gas discharge lamp.
• a device provides for example a current signal to a gas discharge lamp. As a result, a voltage signal across the gas discharge lamp will be present. The combination of these current and voltage signals defines an amount of power provided to the gas discharge lamp.
• the device comprises a control circuit for controlling a supply circuit for supplying the power according to a power versus voltage graph.
• This power versus voltage graph defines a first state for supplying a first amount of power.
• This power versus voltage graph defines a second state for supplying a second amount of power.
• a border between these first and second states is situated at a boundary voltage value of the voltage signal present across the gas discharge lamp, also known as turning point voltage value.
• the control circuit comprises a calculator for calculating the boundary voltage value as a function of a measured voltage value of the voltage signal that has been measured after a predefined time-interval has elapsed. This predefined time-interval is started at a cold start of the gas discharge lamp.
• a more accurate way to find the boundary voltage value has been realized by measuring a voltage value of the voltage signal at a fixed moment in time, such as for example, for a particular kind of lamp, five, six or seven seconds after a cold start of the gas discharge lamp, or such as for example, for a more general kind of lamp, any time value between two and ten seconds, and by calculating the boundary voltage value as a function of this measured voltage value.
• a voltage value of the voltage signal at a fixed moment in time, such as for example, for a particular kind of lamp, five, six or seven seconds after a cold start of the gas discharge lamp, or such as for example, for a more general kind of lamp, any time value between two and ten seconds.
• a further advantage might be that a more accurate boundary voltage value results in more accuracy and in less time required to reach the steady state.
• a voltage value may be measured of another voltage sig- nal derived from said voltage signal present across the gas discharge lamp.
• Said derivation may for example be done a voltage divider.
• the function may take this derivation into account and/or may be based on this derivation.
• Said calculator can be any kind of analog and/or digital machine in hardware and/or software.
• the device is defined by the calculator being arranged for calculating the boundary voltage value as a function of a minimum voltage value of the voltage signal and as a function of a steady state voltage value of the voltage signal.
• each function f (x) may comprise a term p x + q with p and q being selected per function.
• the boundary voltage value may be calculated as a function of more than one minimum voltage value of the voltage signal. Two or more minimum voltage values of the voltage signal may occur for two or more different situations, such as for example two or more different starting temperatures of the lamp. Each minimum voltage value of the voltage signal may only be a minimum value in a certain time-interval, so the voltage signal may have different minimum values in different time- intervals.
• the device is defined by the function of the measured voltage value of the voltage signal comprising a first weighting factor, the function of the minimum voltage value of the voltage signal comprising a second weighting factor, and the function of the steady state voltage value of the voltage signal comprising a third weighting factor, a sum of the weighting factors being equal to a prede- fined value. This way, a most accurate boundary voltage value can be determined.
• the device is defined by the first amount of power comprising an increasing amount of power during a first part of the first state while supplying a maximum current to the gas discharge lamp, the first amount of power comprising a maximum amount of power during a second part of the first state, and the second amount of power comprising a decreasing amount of power until the steady state voltage value of the voltage signal has been reached.
• the increasing amount of power results from increasing voltage values of the voltage signal in combination with the maximum current.
• the maximum amount of power results from increasing voltage values of the voltage signal in combination with a decreasing current.
• the decreasing amount of power results from increasing voltage values of the voltage signal in combination with an even more decreasing current.
• the device is defined by the power versus voltage graph defining a third state for supplying a third amount of power, the third state starting at the steady state voltage value of the voltage signal, the third amount of power comprising a stable amount of power.
• a stable amount of power is an amount that changes less than for example 1% per second, preferably less than 0.1% per second.
• the device is defined by the control circuit comprising a memory for storing the measured voltage value of the voltage signal and comprising a processor for updating the measured voltage value stored in the memory. After a start of the gas discharge lamp, a stored measured value is used to calculate a boundary voltage value, and a more recent measured value is used for updating the stored measured value.
• the device is defined by the control circuit comprising a memory for storing the measured voltage value of the voltage signal and the minimum voltage value of the voltage signal and the steady state voltage value of the voltage signal and comprising a processor for updating the voltage values stored in the memory. After a start of the gas discharge lamp, stored values are used to calculate a boundary voltage value, and more recent values are used for updating the stored values.
• the device is defined by the device being an electronic ballast for the gas discharge lamp.
• a system comprising the device and comprising the supply circuit, in which case the system can be a power supply, and/or comprising the gas discharge lamp, in which case the system can be a light.
• the system can be a power supply, and/or comprising the gas discharge lamp, in which case the system can be a light.
• a combination of a power supply and a light is not to be excluded.
• a method for providing an amount of power to a gas discharge lamp, the method comprising a step of controlling a supply of the power according to a power versus voltage graph, the power versus voltage graph defining a first state for supplying a first amount of power, the power versus voltage graph defining a second state for supplying a second amount of power, the first state ending at a boundary voltage value of a voltage signal and the second state starting at the boundary voltage value, the step of controlling comprising a sub-step of calculating the boundary voltage value as a function of a measured voltage value of the voltage signal that has been measured after a predefined time-interval from a cold start of the gas discharge lamp.
• a computer program product is provided for performing the step of the method.
• a medium for storing and comprising the computer program product.
• Embodiments of the system and of the method correspond with the embodiments of the device.
• the boundary voltage value should (also) depend on a relatively stable voltage value of the voltage signal.
• a basic idea might be that for a power versus voltage graph of a gas discharge lamp, the boundary voltage value is to be calculated as a function of a measured voltage value of the voltage signal that has been measured after a predefined time- interval from a cold start.
• a problem to provide an improved device has been solved.
• a further advantage might be that a more accurate boundary voltage value results in more accuracy and in less time required to reach the steady state.
• Fig. 1 shows a power versus voltage graph
• Fig. 2 shows a system comprising a device
• Fig. 3 shows a control circuit
• Fig. 4 shows a power defining algorithm
• Fig. 5 shows a boundary voltage as a function of a timed voltage
• Fig. 6 shows a voltage as a function of a time for Fig. 5
• Fig. 7 shows a boundary voltage as a function of a minimum voltage
• Fig. 8 shows a voltage as a function of a time for Fig. 7,
• Fig. 9 shows a boundary voltage as a function of a steady state voltage
• Fig. 10 shows a voltage as a function of a time for Fig. 9, and
• Fig. 11 shows a measured boundary voltage versus a calculated boundary voltage.
• a power versus voltage graph 10 of a gas discharge lamp is shown.
• the power versus voltage graph 10 defines a first state 11 for supplying a first amount of power.
• the power versus voltage graph 10 defines a second state 12 for supplying a second amount of power.
• the first state 11 ends at a boundary voltage value Ub of a voltage signal and the second state 12 starts at the boundary voltage value Ub.
• the first amount of power comprises an increasing amount of power during a first part of the first state 11 while supplying a maximum current I max to the gas discharge lamp.
• the first amount of power comprises a maximum amount of power P max during a second part of the first state 11.
• the second amount of power comprises a decreasing amount of power until a steady state voltage value U stst of the voltage signal has been reached.
• the power versus voltage graph 10 defines a third state 13 for supplying a third amount of power.
• the third state 13 starts at the steady state voltage value U stst .
• the third amount of pow- er comprises a stable amount of power.
• a system 6 comprising a device 1.
• the system 6 further comprises a gas discharge lamp 2 connected to a supply circuit 4 for supplying an amount of power according to the power versus voltage graph 10 shown in the Fig. 1.
• the supply circuit 4 supplies for example a current signal to the gas discharge lamp 2, which current signal results in a voltage signal across the gas discharge lamp 2.
• a combination of these current and voltage signals defines an amount of power.
• the supply circuit 4 is for example connected to a rectifier 5 for rectifying a mains voltage. Alternatively, a battery may be used.
• the device 1 comprises a control circuit 3 connected to the gas discharge lamp 2 (in parallel to the supply circuit 4) and for example connected to the rectifier 5 (in parallel to the supply circuit 4).
• a control output of the control circuit 3 is connected to a control input of the supply circuit 4.
• an ignition circuit may be present (not shown).
• the control circuit 3 comprises a calculator 30 for calculating the boundary voltage value U b as a function of a measured voltage value U T of the voltage signal that has been measured after a predefined time-interval from a cold start of the gas discharge lamp 2.
• the calculator 30 may further calculate the boundary voltage value Ub as a function of a minimum voltage value U min of the voltage signal and as a function of a steady state voltage value U stst of the voltage signal.
• An output of the calculator 30 constitutes the control output of the control circuit 3 and an input of the calculator 30 is for example connected to a processor 32.
• the processor 32 is connected to a memory 31 and is for example connected to a voltage determining circuit 33 and a feeding circuit 34.
• the feeding circuit 34 for example feeds the calculator 30, the memory 31, the processor 32 and the voltage determining circuit 33.
• the voltage determining circuit 33 determines the measured voltage value U T of the voltage signal by for example measuring this voltage value after a predefined time- interval from a cold start of the gas discharge lamp 2 in response to an instruction from the processor 32.
• the voltage determining circuit 33 may further determine other voltage values of the voltage signal by for example measuring these voltage values and supplying the measured voltage values to the processor 32 to for example find the minimum voltage value U min of the voltage signal and the steady state voltage value U stst of the voltage signal by for example comparing the measured voltage values with each other.
• the processor 32 may thereto comprise an analog comparator or comparing function, alternatively this analog comparator or comparing function may be located inside the voltage determining circuit 33 etc.
• the voltage determining circuit 33 may comprise an analog to digital converter, and the processor 32 may then comprise a digital comparator or comparing function, alternatively this digital comparator or comparing function may be located inside the voltage determining circuit 33 etc.
• the calculator 30 may form part of the processor 32, or vice versa.
• the memory 31 stores the measured voltage value U T of the voltage signal and the processor 32 updates the measured voltage value U T stored in the memo- ry 31.
• the memory 31 may further store the minimum voltage value U min of the voltage signal and the steady state voltage value U stst of the voltage signal and the processor 32 may further update these voltage values stored in the memory 31.
• one or more stored values may be used to calculate the boundary voltage value Ub, and one or more recent values may be used for updating the stored values.
• the units 30-33 may be hardware units and/or software units and may form part of a computer or a microcontroller or analog and/or digital control circuitry etc.
• a power defining algorithm is shown.
• a measured voltage value U is presented.
• a (calculated) boundary voltage value Ub is presented.
• a (measured) steady state voltage value U stst is presented.
• differences are determined, and at a block 45 a division is made such that at the output of the block 45 a normalized voltage value U nor m is available:
• Unorm (U-U stst ) / (Ub-U stst ).
• This normalized voltage value U nor m is offered to a block 46 that for example calculates a polynomial 15 x 3 + 13 x 2 + 7 x + 35 or any other kind of polynomial.
• a maximum power P max and a minimum power P min are defined, and at a block 49, the information from the blocks 46, 47 and 48 is converted into an output power defined at a block 50 and to be provided to the gas discharge lamp 2.
• the calculated polynomial has a value between the maximum power P max and the minimum power P min , this value is offered, if said value is larger than the maximum power P max , this maximum power P max is offered, and if said value is smaller than the minimum power P min , this minimum power P min is offered.
• a boundary voltage Ub (V) as a function of the measured voltage U T (V) is shown.
• the measured voltage value U T of the voltage signal is to be measured after a predefined time-interval T from a cold start of the gas discharge lamp 2.
• the Fig. 6 shows a voltage U (V) as a function of a time t (s) for the Fig. 5.
• Ub can be calculated.
• a boundary voltage U b (V) as a function of a minimum voltage U min (V) is shown.
• the Fig. 8 shows a voltage U (V) as a function of a time t (s) for the Fig. 7.
• Ub can be calculated.
• a boundary voltage Ub (V) as a function of a steady state voltage U stst (V) is shown.
• the Fig. 10 shows a voltage U (V) as a function of a time t (s) for the Fig. 9.
• Ub can be calculated.
• a possible algorithm might be as follows. After the predefined time- interval T, such as for example five, six or seven seconds for a particular kind of gas discharge lamp 2, or such as for example for a more general kind of lamp any time value between two and ten seconds, the voltage value U T of the voltage signal is to be measured. This measured voltage value U T of the voltage signal is to be compared with a previous voltage value U T stored in the memory 31. In response to a first comparison result (non-cold start) the previous voltage value U T stored in the memory 31 is to be replaced by the measured voltage value U T of the voltage signal.
• the previous voltage value U T stored in the memory 31 is to be replaced by a new voltage value U T depending on for example the measured voltage value U T of the voltage signal and one or more, such as for example 20, previously stored voltage values U T .
• the steady state voltage value U stst of the voltage signal is to be measured.
• This steady state voltage value U stst of the voltage signal is to be compared with a previous steady state voltage value U stst stored in the memo- ry 31.
• the previous steady state voltage value U stst stored in the memory 31 is to be replaced by the measured steady state voltage value Ustst of the voltage signal.
• the previous steady state voltage value U sts t stored in the memory 31 is to be replaced by a new steady state voltage value U sts t depending on for example the measured steady state vol- tage value U sts t of the voltage signal and one or more previously stored steady state voltage values U st st.
• a new boundary voltage value Ub is to be calculated, and the new boundary voltage value Ub and the new steady state voltage value Ustst can be used for a next calculation of the amount of power to be provided etc.
• a measurement / determination result can be used for updating the (calculated) other one.
• a device 1 for providing an amount of power to a gas discharge lamp 2 comprises a control circuit 3 for controlling a supply circuit 4 for supplying the power according to a power versus voltage graph 10.
• a calculator 30 calculates a boundary voltage value as a function of a measured voltage value of a voltage signal that has been measured after a predefined time-interval from a cold start of the gas dis- charge lamp 2. A more accurate boundary voltage value results in more accuracy and in less time required to reach a steady state.
• the calculator 30 may be arranged for calculating the boundary voltage value as a function of a minimum voltage value of the voltage signal and of a steady state voltage value of the voltage signal.
• a memory 31 may store voltage values of the voltage signal and a processor 32 may update these voltage values.
• a computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

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• 2009
  • 2009-11-03 WO PCT/IB2009/054877 patent/WO2010052641A2/en not_active Ceased
  • 2009-11-03 EP EP09771414A patent/EP2345311B1/en active Active
  • 2009-11-03 CN CN200980144373.3A patent/CN102210195B/zh active Active
  • 2009-11-03 US US13/126,256 patent/US10542612B2/en active Active
  • 2009-11-03 JP JP2011533920A patent/JP6017787B2/ja active Active

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