WO2014021992A2 - Ballast pour lampes à décharge gazeuse - Google Patents

Ballast pour lampes à décharge gazeuse Download PDF

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Publication number
WO2014021992A2
WO2014021992A2 PCT/US2013/044917 US2013044917W WO2014021992A2 WO 2014021992 A2 WO2014021992 A2 WO 2014021992A2 US 2013044917 W US2013044917 W US 2013044917W WO 2014021992 A2 WO2014021992 A2 WO 2014021992A2
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WO
WIPO (PCT)
Prior art keywords
power
stage
coupled
operating voltage
ballast
Prior art date
Application number
PCT/US2013/044917
Other languages
English (en)
Other versions
WO2014021992A3 (fr
Inventor
Zhijun Luo
Original Assignee
General Electric Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Company filed Critical General Electric Company
Priority to US14/413,897 priority Critical patent/US20150195893A1/en
Publication of WO2014021992A2 publication Critical patent/WO2014021992A2/fr
Publication of WO2014021992A3 publication Critical patent/WO2014021992A3/fr

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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
    • H05B41/282—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
    • H05B41/2825—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 by means of a bridge converter in the final stage
    • H05B41/2828—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 by means of a bridge converter in the final stage using control circuits for the switching elements
    • 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
    • H05B41/2885—Static converters especially adapted therefor; Control thereof
    • H05B41/2886—Static converters especially adapted therefor; Control thereof comprising a controllable preconditioner, e.g. a booster
    • 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
    • H05B41/2885—Static converters especially adapted therefor; Control thereof
    • H05B41/2887—Static converters especially adapted therefor; Control thereof characterised by a controllable bridge in the final stage
    • 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
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Definitions

  • the aspects of the present disclosure relate generally to gas discharge lamps and in particular to improved electronic ballasts for powering gas discharge lamps.
  • Gas discharge lamps belonging to a family of lighting devices such as fluorescent lamps used in residential and industrial lighting and high intensity discharge lamps used in stadium lighting and automobile headlamps, have specialized power requirements.
  • a high voltage is used to ionize gases contained in the lamp tube and initiate an arc within the lamp.
  • the lamp Once an arc has been established and the lamp has warmed to its desired operating temperature, the lamp enters a normal operating phase where it exhibits a negative resistance characteristic.
  • Negative resistance is a condition where lamp current varies inversely with applied voltage and can create an unstable condition leading to excessive lamp current which may deteriorate or destroy the lamp. Thus, it is necessary to carefully control the lamp current to avoid damaging the lamp.
  • a ballast is an electrical apparatus used to provide power to a load, such as a gas discharge lamp, and to regulate its current.
  • the ballast When driving gas discharge lamps, the ballast is configured to provide a high voltage to ignite the lamp, regulate the current at safe operating levels during normal operation, and to shut down lamp power when a lamp fails or is removed. If the ignition voltage is applied for too long, the lamp may be overstressed or otherwise damaged. Under certain conditions, application of the ignition voltage may fail to ignite the lamp within a safe period of time. When this occurs, the ignition voltage must be removed to allow the lamp to cool before another ignition attempt is made. The process of applying an ignition voltage, checking for ignition, then waiting for a cooling period is referred to as an ignition cycle.
  • the ballast is typically configured to apply several ignition cycles to the lamp in order to achieve reliable lamp starting under a wide range of environmental conditions and to enter a failure mode where lamp power is shut down if the lamp fails to start after predefined number of ignition cycles has been attempted.
  • Typical modern lamp ballasts include multiple power conversion stages. While various combinations of stages may be used, a common set of stages includes an AC to DC conversion stage, a power factor correction (PFC) stage, a power regulator stage, and a DC to AC inverter stage. Alternating current (AC) grid power is rectified and filtered to create rectified direct current (DC) power by the AC to DC conversion stage. The rectified power is passed through the PFC stage to keep the current drawn from the power grid in phase with the voltage of the power grid thereby maintaining a near unity power factor for efficient power usage.
  • AC Alternating current
  • DC direct current
  • the PFC stage may be followed by a power regulator, typically configured as a buck regulator, which receives power factor corrected DC power from the PFC stage and produces a regulated DC power to control a power delivered to the lamp.
  • a DC to AC inverter converts the regulated DC power into an AC power to drive the load.
  • Each stage in the ballast typically uses an operating voltage, such as a common collector voltage, Vcc, to operate control and logic circuits internal to each stage.
  • Vcc common collector voltage
  • These operating voltages are often provided from a secondary winding magnetically coupled to an energy storage inductor in the PFC stage.
  • Vcc common collector voltage
  • a linear power supply is typically included to maintain the control voltage. Linear supplies of this type dissipate significant amounts of power resulting in reduced ballast efficiency and the need for expensive and relatively large power components.
  • a typical AC to DC inverter stage as included in multi-stage ballasts uses controllably conductive switching devices to chop a regulated DC power to produce an AC output power for the lamp.
  • the inverter stage operates the switching device to alternately apply a forward current to the output power then apply a reverse current to the output power.
  • transition periods The periods where current is changing direction, i.e. transitioning from forward current to reverse current and from reverse current to forward current, are referred to as transition periods, and when the inverter is reversing the direction of the current it is said to be in transition. Further, when an inverter begins reversing the current it is said to be entering transition.
  • Spikes of current such as the spikes occurring during inverter transition, have large amplitude but contain little RMS power resulting in a high CCF value.
  • a lamp ballast with a CCF close to unity will provide much better lamp life than a ballast with a large CCF, such as a CCF greater than about 2.
  • ballast circuits that solve at least some of the problems identified above.
  • the exemplary embodiments overcome one or more of the above or other disadvantages known in the art.
  • the multi-stage ballast includes a power factor correction stage configured to receive an AC input power and produce a phase corrected DC power, a buck regulator stage coupled to the phase corrected DC power and configured to produce a regulated DC power.
  • the buck regulator stage includes a buck switch.
  • the ballast also includes a DC to AC inverter stage coupled to the regulated DC power and configured to produce an AC lamp power, and a microcontroller coupled to the inverter stage and to the buck switch. The microcontroller is configured to determine when the inverter enters transition and to shut off the buck switch for a predetermined period of time after the inverter enters transition.
  • Another aspect of the present disclosure relates to an electroluminescent device.
  • the electroluminescent device includes an AC to DC rectifier device configured to receive an AC input power and produce a rectified DC power, a power factor correction stage coupled to the rectified DC power and configured to produce a phase corrected DC power, and a buck regulator stage coupled to the phase corrected DC power and configured to produce a regulated DC power.
  • the buck regulator stage includes a buck switch.
  • the electroluminescent device also includes a DC to AC inverter stage coupled to the regulated DC power and configured to produce an AC lamp power, a microcontroller coupled to the inverter stage and to the buck switch, an internal power supply coupled to the rectified DC power and configured to produce a first operating voltage, and a gas discharge lamp coupled to the AC lamp power.
  • the power factor correction stage, the buck regulator stage, and the inverter stage each include control circuitry coupled to the first operating voltage, and the microcontroller is configured to determine when the ballast is in a standby mode and to turn off the first operating voltage while the ballast is in standby mode.
  • Figure 1 illustrates a block diagram of a multi-stage ballast for powering a gas discharge lamp incorporating aspects of the present disclosure.
  • Figure 2 illustrates a block diagram of an exemplary architecture for supplying operating voltages to control circuitry within a multi-stage ballast incorporating aspects of the present disclosure.
  • Figure 3 illustrates a schematic diagram of an exemplary embodiment of a switching circuit incorporating aspects of the present disclosure.
  • Figure 4 illustrates an embodiment of a buck regulator and an inverter incorporating aspects of the present disclosure.
  • Figure 5 illustrates a graph showing current delivered to the load by a typical multi-stage ballast.
  • Figure 6 illustrates a graph showing lamp current delivered to a load by a multistage ballast employing a CCF control method incorporating aspects of the present disclosure.
  • Figure 7 illustrates an embodiment of a buck control circuit that may be used to implement a CCF control method in multi-stage ballasts incorporating aspects of the present disclosure.
  • FIG. 1 there can be seen a block diagram of a multi-stage ballast 100 that is appropriate for providing power and current regulation for loads 110 such as high intensity discharge (HID) lamps or other types of gas discharge lamps and electroluminescent devices.
  • the ballast 100 is configured to receive input power 101 from a local mains power grid or other suitable AC power source such as the 120 volt, 60 Hertz power available in the United States, 50 Hertz 230 volt power available in many European countries, as well as other locally available grid power.
  • a rectifier stage 102 converts the AC grid power 101 to rectified power 103 which is provided to a power factor correction (PFC) stage 104.
  • PFC power factor correction
  • the PFC stage 104 is configured to keep the current drawn from the grid power 101 in phase with the voltage of the grid power thus maintaining a power factor of the ballast at or near unity.
  • the PFC stage 104 includes a switched mode power converter 128 typically configured as a boost topology with an inductive energy storage element (not shown) and a controllably conductive switching device (not shown).
  • Control circuitry 130 configured to operate the switched mode power converter 128 in transition mode such that the current drawn from the input power 101 is in phase with the voltage of the input power 101.
  • Control circuitry 130 includes various discrete components and integrated circuits, such as for example the transition mode PFC controller L6562D manufactured by STMICROELECTRONICS, to monitor signals within the PFC stage 104 and operate the switched mode power converter 128.
  • An operating voltage 120 is provided to the control circuitry 130 by an operating voltage power supply 112 to provide operating power to its components and integrated circuits.
  • the phase corrected power 105 produced by the PFC stage 104 is provided to a power regulator stage 106 that produces a regulated DC power 107.
  • the power regulator is typically configured as a switched mode buck regulator 132 that includes a controllably conductive switching device, known as a buck switch.
  • the buck switch is rapidly turned on and off by the buck control circuitry 134 to maintain a substantially constant level of power in the regulated DC power 107.
  • the control circuitry 134 can be configured to maintain a substantially constant voltage or a substantially constant current in the regulated DC power 107.
  • the buck control circuitry 134 may include both discrete components and integrated circuits, such as for example the L6562D described above, or similar integrated circuits, and also receives an operating voltage 120 from an operating voltage power supply 112.
  • a DC-AC inverter stage 108 converts the regulated DC power 107 to an AC lamp power 109 which is used to drive a gas discharge lamp or other load 110 requiring regulated AC power.
  • An inverter power section 136 in the DC-AC inverter stage 108 includes switching devices configured in a bridge circuit to chop the regulated DC power 107 to produce an AC power and includes a resonant tank to shape the chopped DC power as required to drive the lamp or other load 110.
  • Inverter control circuitry 138 receives command signals from a microcontroller unit 114 and generates control signals 126 to drive the inverter power section 136.
  • the control signals 126 also include status signals generated by the inverter control circuitry 138 which provide the microcontroller 114 with information for making determinations and decisions. Similar to control circuitry 130, 134 in the other power stages, 104, 106, the inverter control circuitry 138 receives an operating voltage 120 to operate its components and integrated circuits.
  • Multi-stage ballast 100 includes an operating voltage power supply 112 used to supply voltages to operate control circuitry within the ballast. Two sources are used to provide input power for the operating voltage power supply 112. During normal ballast operation a coupled power 118 is received from a secondary winding magnetically coupled to an energy storage inductor of the switched mode power converter 128. As will be discussed further below, during certain operating conditions, the coupled power 118 is insufficient, thus an alternate source of power or second power source 116 is provided to the operating voltage power supply 112 by coupling it directly to the rectifier stage 102.
  • the operating voltage power supply 112 is used to provide a common collector voltage (VCC) known as an operating voltage 120 to low level control circuitry, 130, 134, 138 in each of the power stages 104, 106, 108, and also provides a low level voltage (VDD) 124 to operate the microcontroller 114.
  • VCC common collector voltage
  • VDD low level voltage
  • Low-load or no-load conditions occur during periods where the load lamp 110 is shut down such as during cool down periods between each ignition cycle or when a lamp has failed or has been removed.
  • the alternate source of input power 116 is drawn directly from the rectified input power 103.
  • the microcontroller 114 is coupled to the DC-AC inverter stage 108.
  • Control signals 126 allow the microcontroller to determine various conditions within the DC-AC inverter stage 108 that may affect the PFC controller 104 and the power regulator stage 106. These conditions include low- load or no-load conditions that prevent the PFC controller 104 from supplying sufficient primary coupled power 118 to the operating voltage power supply 112, and transitions of the DC-AC inverter stage 108 which may induce harmful voltage spikes in the regulated DC power 107 produced by the power regulator stage 106.
  • the microcontroller unit 114 provides high level control and coordination functions to keep the PFC controller stage 104, power regulator stage 106, and DC-AC inverter stage 108, operating efficiently and to provide functionality such as for example lamp restarting and cool-down.
  • the microcontroller 114 can comprise a small general purpose computer typically constructed on a single integrated circuit or small circuit board containing a processor, memory, and programmable input/output peripherals.
  • the microcontroller unit 114 includes an analog-to-digital converter, digital-to-analog converter, and/or on board counters capable of providing control to the multi-stage ballast 100.
  • the microcontroller unit 114 includes a processor capable of executing computer instructions as well as manipulating and moving data, and a memory capable of storing computer instructions and data.
  • FIG. 2 illustrates a block diagram of an exemplary architecture 200 for an operating voltage power supply 112 appropriate for supplying VDD, an operating voltage, to control circuitry within a multi-stage ballast 100.
  • a linear power supply 202 is coupled directly to an the second power source 116, such as the rectified input power 103, to allow the linear supply 202 to provide power immediately when input power, such as input power 101, is applied to the ballast 100.
  • Linear supply 202 can provide power 206 before the PFC stage 104 is started and when the DC-AC inverter stage 108 is shutdown.
  • Linear supply 202 provides power 206 in the form of an internal voltage that is used by a low level supply 212 to provide VDD 124 that is used by the microcontroller 114.
  • the internal voltage of power 206 is also used by an operating voltage power regulator 214 to provide an operating voltage to control circuitry within the power stages 104, 106, and 108.
  • a coupled power supply 204 receives coupled power 118 from the switched mode power converter 128 and provides an alternate source for the operating voltage power regulator 214.
  • the multi-stage ballast 100 needs to support several lamp operating modes. When the load or lamp 110 is lit the ballast 100 is in steady state and the ballast 100 operates under a normal load, i.e. the ballast 100 is providing a normal amount of current to the lamp 110. During ignition, the ballast 100 applies a high ignition voltage to the lamp 110 and is subjected to a light load.
  • the ballast 100 During cool-down periods, which are the periods between bursts of ignition voltage applied at startup, during lamp failure, or while a lamp is removed, the ballast 100 is in shutdown mode and is subjected to low- load or no-load in which no lamp current or very little lamp current is flowing.
  • a linear power supply such as the linear supply 202, dissipates an amount of power proportional to the amount of current being supplied.
  • a coupled supply such as the coupled supply 204 receives regulated power from a switching regulator such as the boost regulator in the PFC stage 104 and thus dissipates significantly less power. It is therefore desirable to use the coupled supply 204 as much as possible and only draw power from the linear supply 202 when the coupled supply 204 is not able to provide the required operating voltage 206.
  • the coupled supply 204 uses magnetic coupling to draw power from an energy storage inductor in the PFC stage 104, which is typically a boost type switching regulator, and therefore can only supply power while current is flowing through the PFC stage's inductor.
  • the design of the coupled supply 204 can support the power dissipation of VCC 120 and VDD 124 during light and normal loads. However, when the ballast 100 is in a low- load or no-load condition there is insufficient power produced by the coupled supply 204 and the power 206 must be supplied by the linear power supply 202.
  • the operating voltage regulator 214 is configured to draw power from the coupled supply 204 whenever possible and to draw power from the linear supply 202 only when the coupled supply 204 is not providing sufficient power.
  • Typical ballast designs create the linear supply using power resistors which are reliable but waste significant amounts of power. Alternatively, switching supplies have been used to reduce the amount of wasted power but increase the cost of the ballast and adversely impact reliability.
  • An alternative approach disclosed herein is to include an operating voltage control switch 216 to control the operating voltage power regulator 214.
  • Operating voltage control switch 216 is coupled to the microcontroller 114 allowing the microcontroller 114 to disconnect the operating voltage power regulator 214 from the linear power supply 202 during periods where it is not necessary to operate control circuitry in the power stages 104, 106, 108. For example, when the ballast 100 enters into a low- load or no-load condition, the switch 216 may be turned off.
  • ballast 100 may be put into a standby mode where the amount of operating voltage power dissipation is significantly reduced.
  • Standby mode is where the ballast 100 is providing little or no current to the lamp 110 such as during cool- down periods, or when a lamp fails or is removed.
  • the control circuitry continues to receive power and continues to operate even though it is not providing any power to the load.
  • a multi-stage ballast 100 that includes an operating voltage control switch 216 and a microcontroller 114 programmed to operate the switch 216, can significantly reduce power dissipated during standby mode.
  • a typical multi-stage ballast 100 uses operating voltage 120 to provide a common collector voltage of about 15 volts at about 8 milliamps.
  • VDD 124 requires a much lower power level of about 5 volts at less than 1 milliamp.
  • a ballast using power resistors in the linear supply 202 will typically dissipate about 3.2 watts. This level of dissipation requires a pair of 2 watt power resistors or equivalent power transistor in the linear supply.
  • the power dissipation may be reduced to less than approximately 0.4 watts. In addition to improved energy efficiency, the reduced power dissipation of less than one half watt, allows the power resistors used in a traditional solution to be replaced with less costly surface mount resistors.
  • FIG. 3 illustrates a schematic diagram of an exemplary embodiment of a switching circuit appropriate for placing the ballast 100 in standby mode.
  • a circuit of this type may be used as the operating voltage power control switch 216 in the low level supply architecture 200 described above.
  • the switching circuit receives a common collector voltage at a positive supply rail VCC_IN.
  • a switching transistor Q22 selectively connects the supply rail VCC IN to the output voltage VCC OUT.
  • a diode D21 not only prevents the output voltage VCC OUT from exceeding the input voltage VCC IN, but also provides a current flow to supply the VDD from VCC OUT.
  • a filter capacitor C20 is connected in parallel with a Zener diode D22 between the output voltage VCC OUT and circuit ground 302 to stabilize and maintain the output voltage VCC OUT at a constant voltage, such as for example about 18 volts.
  • a control signal VCC CTR is applied to the gate of a field effect transistor Q21 and a resistor R30 is used to provide a bias voltage to keep the transistor Q21 turned off when the control signal VCC CTR is held high.
  • a pair of resistors, R28 and R29 forms a resistor divider network that is connected in series between the supply voltage VCC IN and the transistor Q21. Transistor Q21 selectively connects the resistor divider R28, R29 to circuit ground 302.
  • a central node 304 between the two resistors R28, R29, is connected to the base of the switching transistor Q22.
  • the control signal VCC CTR When the control signal VCC CTR is pulled to a low level, it turns the transistor Q21 on, which connects the pair of resistors R28, R29 to ground, creating a voltage across resistor R28 to turn the switching transistor Q22 on.
  • the output VCC OUT When the switching transistor Q22 is on, the output VCC OUT is connected to the input VCC IN thereby providing the input voltage to any components connected to the output VCC OUT.
  • a microcontroller such as the microcontroller 114 described above with reference to the multi-stage ballast 100, may be connected to VCC CTR to operate the switching circuit 300.
  • the microcontroller 114 can determine when the ballast is in a no-load condition.
  • the microcontroller 114 can be programmed to take advantage of knowledge of the ballast's operating mode and place the ballast in standby mode by opening the operating voltage control switch 216 to reduce the amount of power dissipated by the ballast.
  • FIG. 4 illustrates an embodiment of a power regulator stage 106 and a DC-AC inverter stage 108 that may be used to reduce the CCF of regulated DC power 107 thereby reducing current spikes delivered to a load 410 through the DC-AC inverter stage 108.
  • Circuitry in the power regulator stage 106 which in one embodiment is a buck regulator, includes power circuits 402 and control circuits 406.
  • the power circuitry 402 is a switching mode type regulator configured using a buck regulator topology as is known in the art and includes a controllably conductive switch 404 known as a buck switch.
  • the buck switch 404 is switched on and off by the control circuit 406 to regulate the DC power 107.
  • Control circuitry 406 is configured to monitor various values within the power regulator stage 106, such as the amount of output power, value of the output voltage, value of the input voltage, and other values as appropriate, and adjusts the duty cycle of the buck switch 404 to maintain the desired DC power 107 characteristics.
  • a duty cycle as used herein refers to the ratio of on-time, which is the period of time during which the buck switch 404 is conducting current, to off-time, which is the period of time during which the buck switch 404 is not conducting current, of the controllably conductive switching device 404.
  • Control circuitry 406 receives a control voltage 120, also known as a common collector voltage (Vcc), from a suitable operating voltage power source as described above.
  • the control circuitry 406 may be of any suitable type, including discrete electronic components and/or integrated circuits, appropriate for controlling the power circuitry 402 and maintaining desired buck regulator output power 107 characteristics.
  • the DC-AC inverter stage 108 is configured to receive the regulated DC power
  • the load 410 includes a lamp and may also include a resonant tank circuit and/or other current controlling components that help form a required lamp power from the inverter voltage, Vinv.
  • the inverter includes an H- bridge power circuit 422 which is formed from four controllably conductive switching devices 412, 414, 416, 418, such as metal oxide semiconductor field effect transistors (MOSFETs), and receives its operating voltage 120 from a suitable power source and provides a set of external control signals 126 which allow the DC-AC inverter stage 108 to be controlled by an external device such as a microcontroller 1 14.
  • MOSFETs metal oxide semiconductor field effect transistors
  • the four switching devices 412, 414, 416, 418 are alternately turned on and off in pairs by control circuitry 420 to create a square wave inverter voltage Vinv to drive the load 410.
  • First switching devices 412 and 418 are turned on, while switching devices 414 and 416 are turned off, to apply a forward polarity or positive inverter voltage Vinv to the load 410, then switching devices 414 and 416 are turned on, while switching devices 412 and 418 are turned off, to apply a reverse polarity inverter voltage Vinv to the load 410.
  • all four switching devices 412, 414, 416, and 418 When changing the polarity of the inverter voltage Vinv, all four switching devices 412, 414, 416, and 418, generally should be turned off for a brief amount of time to prevent potentially harmful shoot through currents, before turning on the alternate pair of switches. Once the alternate pair of switches is activated it takes a finite amount of time for the switching devices to begin conducting. The period of time during which the inverter voltage is changing polarity is referred to as the inverter transition period or just inverter transition.
  • FIG. 5 illustrates a graph 500 showing current 502 delivered to the load 410 by the H-bridge 422.
  • the magnitude of lamp current is represented on the vertical axis in amperes with each major division representing one ampere.
  • Time is represented on the horizontal axis in seconds with each division representing 10 milliseconds.
  • a large current spike 504 is created each time the inverter transitions between positive and negative voltage.
  • the RMS value of the lamp current 502 is about 1.4 amperes while the peaks 504 are about 2.5 amperes yielding a CCF of about 1.8.
  • an additional control input 144 is included and is configured to stop pulse width modulation and turn the buck switch 404 off when the control signal 144 is activated.
  • the exemplary ballast 100 described above includes a microcontroller 114 configured to operate the DC-AC inverter stage 108 through control signals 126.
  • microcontroller 114 is able to determine when the DC-AC inverter stage 108 is in transition by examining the control signals 126 and activate the buck control signal 144.
  • the microcontroller 114 is programmed to perform a CCF control method where the buck control signal 144, is activated for a predetermined period of time whenever the microcontroller determines that the inverter stage 108 enters transition.
  • FIG. 6 illustrates a graph 600 showing lamp current 602 delivered to a load 410 by a ballast employing the CCF control method just described.
  • the magnitude of lamp current is represented on the vertical axis in amperes with each major division representing one ampere.
  • Time is represented on the horizontal axis in seconds with each division representing 10 milliseconds.
  • the graph 600 shows that the current spikes 604 occurring at each transition are nearly eliminated by the buck control scheme yielding a CCF of close to one.
  • FIG. 7 illustrates an exemplary embodiment of a buck control circuit 700 that may be used to enable and disable switching in certain embodiments of the power regulator stage 106.
  • the buck control circuit 700 may be used to enable a microcontroller 114 to implement the CCF control method described above. It is common to use integrated circuits U80 to control the buck switch 404 in power regulator stages 106.
  • Buck regulators using integrated circuits U80 such as the L6562 manufactured by STMICROELECTRONICS or the UCC 28050 manufactured by TEXAS INSTRUMENTS are known and these buck regulator implementations include a zero current detection (ZCD) input, pin 5, which is used to operate the switching supply in transition mode.
  • ZCD zero current detection
  • the buck inductor current is indirectly sensed through a bias winding on the boost inductor and is used to generate a zero current detection signal 702 to drive the ZCD input of the integrated circuit U80.
  • the integrated circuit U80 is configured so that a negative going edge on the ZCD input pin 5 causes the buck switch 404 to be turned on.
  • a negative going edge will not appear at the ZCD input 5 and the buck switch 404 will not be turned on.
  • a simple crest factor control signal CF CON input can be created by taking advantage of the functionality of the ZCD input pin 5.
  • the microcontroller 114 outputs a logical 'zero' or 'false' value on the CCF control signal output 126 which is connected to the CCF CON signal, the diode D80 becomes reverse biased and the zero crossing detection signal 702 is allowed to drive the ZCD pin 5.
  • the diode D80 When the microcontroller 114 outputs a logical 'one' or 'true value on the CCF control signal 126, the diode D80 is forward biased and the ZCD pin 5 will not be provided with a negative going edge and the buck switch 404 will remain off until the microcontroller 114 outputs a logical 'zero' on the output pin 126.
  • other circuits may be used to provide the CCF control input 144 on the power regulator stage 106 such that activation of the CCF control input turns the buck switch 404 off.

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  • Circuit Arrangements For Discharge Lamps (AREA)
  • Dc-Dc Converters (AREA)

Abstract

La présente invention concerne un ballast à étages multiples pour l'alimentation d'une lampe à décharge gazeuse, comprenant un étage de correction du facteur de puissance conçu pour recevoir une puissance d'entrée CA et produire une puissance CC à correction de phase, un étage régulateur-abaisseur de tension couplé à la puissance CC à correction de phase et conçu pour produire une puissance CC régulée. L'étage régulateur-abaisseur de tension comprend un commutateur abaisseur de tension. Le ballast comprend également un étage onduleur couplé à la puissance CC régulée et conçu pour produire une puissance de lampe CA, et un microcontrôleur couplé à l'étage onduleur et au commutateur abaisseur de tension. Le microcontrôleur est conçu pour déterminer le moment où l'onduleur entame sa transition et pour fermer le commutateur abaisseur de tension pendant une durée prédéterminée une fois que l'onduleur a entamé sa transition.
PCT/US2013/044917 2012-07-31 2013-06-10 Ballast pour lampes à décharge gazeuse WO2014021992A2 (fr)

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US14/413,897 US20150195893A1 (en) 2012-07-31 2013-06-10 Ballast for gas discharge lamps

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CN201202678848 2012-07-31
CN20120267884.8 2012-07-31

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060113922A1 (en) * 2004-10-29 2006-06-01 International Rectifier Corporation HID buck and full-bridge ballast control IC
US20080278089A1 (en) * 2007-05-07 2008-11-13 Simon Richard Greenwood Active lamp current crest factor control

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060113922A1 (en) * 2004-10-29 2006-06-01 International Rectifier Corporation HID buck and full-bridge ballast control IC
US20080278089A1 (en) * 2007-05-07 2008-11-13 Simon Richard Greenwood Active lamp current crest factor control

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CO M A ET AL: "Microcontrolled electronic gear for HID lamps comparisons with electromagnetic ballast", IECON-2002. PROCEEDINGS OF THE 28TH. ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY. SEVILLA, SPAIN, NOV. 5 - 8, 2002; [ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY], IEEE, NEW YORK,NY, US, vol. 1, 5 November 2002 (2002-11-05), pages 468-472, XP010633202, DOI: 10.1109/IECON.2002.1187553 ISBN: 978-0-7803-7474-4 *

Also Published As

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