Patent Application
20120319588
The present disclosure relates to electronic control devices for lamps and, more specifically, to systems and method for adaptively monitoring and operating electronic ballast for gas discharge lamps.
The statements in this section merely provide background information related to the present disclosure and does not constitute prior art.
Gas-discharge lamps include fluorescent lamps or fluorescent tubes that use electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that causes a phosphor to fluoresce, producing visible light. The excited mercury atoms producing short-wave ultraviolet light can be also controlled to emit UV-A, UV-B and UV-C ultraviolet light used in many applications such as for germicidal purposes. A fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp.
However, lower energy costs are typically offset by the higher initial cost of the lamp. A lamp fixture for a gas discharge lamp is more costly because it requires a ballast to regulate the current through the lamp. Fluorescent lamps are negative differential resistance devices, so as more current flows through them, the electrical resistance of the fluorescent lamp drops, allowing even more current to flow. Connected directly to a constant-voltage power supply, a fluorescent lamp would rapidly self-destruct due to the uncontrolled current flow. To prevent this, fluorescent lamps must use an auxiliary device, a ballast, to regulate the current flow through the gas discharge lamp tube.
The terminal voltage across an operating lamp varies depending on the arc current, the diameter of the lamp tube, the operating temperature, and type of gas used to fill the gas discharge tube. A fixed part of the voltage drop is associated with the lamp electrodes. A general lighting service T12 48 inch (1200 mm) lamp operates at 430 mA, which has a 100 volt drop across the lamp electrodes. High output lamps operate at 800 mA, and some types operate up to 1500 mA. The power level varies from 10 watts per foot (33 watts per meter) to 25 watts per foot (82 watts per meter) of tube length for T12 lamps.
The simplest ballast for alternating current (AC) lamps is an inductor placed in series with the lamp terminal. The inductor consists of a winding on a laminated magnetic core. The inductance of the inductor winding limits the flow of AC current. This type of ballast is used, for example, in 120 volt operated desk lamps using relatively short lamps. Ballasts are rated for the size of lamp and power frequency. Often, the input or mains voltage is insufficient to start a long fluorescent lamp. In such cases, the ballast often includes a step-up transformer that has a substantial amount of leakage inductance that limits the current flow. Additionally, in any type inductive ballast a capacitor can be included in the circuit to provide a power factor correction.
In such Push-pull resonant circuits 300, a considered advantage is that the circuit can tolerate open or short circuited loads indefinitely. As such, circuit 300 is often used in large ballasts 250. It generates a nearly perfect sinusoidal voltage through the lamp 100 with each transistor producing half of the sin wave. The circuit 300 oscillates due to the capacitor C, and the inductance of the transformer T1. The inductor L acts as a constant current source, maintaining the resonant circuit in oscillation by feeding energy into it to compensate for that absorbed by the load, e.g., the lamp 100. The oscillation is triggered by drive circuits 302A and 302B, which pulls up the base-emitter voltage of the transistors. Once the oscillation has started, and before the lamp 100 is ionized, the windings S1 and S2 generate a current to heat the lamp filaments, the output winding S3 of ballast 250 generate the high voltage required to ionize the lamp by initially generating a voltage that effectively connected across an open load.
Once the lamp 100 is ionized, supplementary winding S2 provides the lamp power or drive for the lamp 100. As the impedance of the lamp 100 has fallen, the voltage across the supplementary winding S2 is much smaller in this situation than in start-up. The voltage across the S1 and S3, and consequently the filament currents, is also reduced.
Base drive power for the transistors T1 is provided by means of feedback windings from the output transformer. The collector-current spikes at each switching event are caused by both transistors conducting simultaneously: one in the forward direction, and the other in the reverse, through a collector-base diode.
Gas discharge lamps, such as fluorescent lamps (generally referred herein as gas discharge lamps), can be powered directly from a direct current (DC) power supply that has sufficient voltage to strike an arc. In such cases, the ballast must be resistive, and would consume about as much power as the lamp. When operated from DC, the starting switch is often arranged to reverse the polarity of the supply to the lamp each time it is started since operating a single polarity gas discharge lamp can result in the mercury accumulating at one end of the tube. However, fluorescent lamps are almost never operated directly from DC power. Rather, even where DC power is the primary power source, such as on a motor vehicle, an inverter is used to convert the DC power supply into AC power for powering of the gas discharge lamp. Such an inverter also provides the current-limiting function of the electronic ballast.
The light output and performance of fluorescent lamps is critically affected by the temperature of the wall of the bulb of the lamp as the temperature of the bulb wall affects the partial pressure of mercury vapor within the lamp. Each lamp contains a small amount of mercury, which must vaporize to support the lamp current and generate light. At low temperatures, the mercury is in the form of dispersed liquid droplets. As the lamp warms, more of the mercury is in vapor form. At higher temperatures, self-absorption in the vapor reduces the yield of UV and visible light.
Modern electronic ballasts employ transistors to increase the frequency of the primary input voltage, referred to as the mains voltage, into a higher frequency AC while also regulating the current flow in the lamp. These electronic ballasts take advantage of the fact that gas discharge lamps are more efficient when operated at higher-frequency current. Efficiency of a fluorescent lamp rises by almost 10% at a frequency of 10 kHz as compared to the efficiency of a lamp operating at 60, 100 or 120 Hz. Since introduction in the 1990s, high frequency ballasts have been used in general lighting fixtures with either rapid start or pre-heat lamps. These ballasts convert the incoming power to an output frequency in excess of 20 kHz. This increase in frequency has further increased lamp efficiency. When the AC period is shorter than the relaxation time to de-ionize mercury atoms in the discharge column, the discharge stays closer to optimum operating condition. Electronic ballasts typically work in rapid start or instant start mode. Electronic ballasts are commonly supplied with AC power. The input AC power is converted by the ballast into DC power and then inverted back into a desired lamp powering AC waveform that often have a constant current pulse width and frequency. Depending upon the capacitance and the quality of constant-current pulse-width modulation, the modulation of the lamp powering at 100 or 120 Hz can be largely eliminated.
Modern low cost ballasts utilize a simple oscillator and series resonant LC circuit. When turned on, the oscillator starts, and the LC circuit charges. After a short time, the voltage across the lamp reaches about 1 kV and the lamp ignites. This process is however often too fast to preheat the cathodes. As such, the lamp with the cold cathodes instant-starts in what is referred to as cold cathode mode. In this mode, the cathode filaments are used for protection of the ballast from overheating if the lamp does not ignite. A few manufacturers use positive temperature coefficient (PTC) thermistors to disable instant starting. By providing power to the cathodes without allowing the lamp to start, the cathode and filaments can be preheated so that the lamp can start once the power is applied.
More complex electronic ballasts use programmed starting methods. In these cases, the output AC frequency is started at a higher frequency than the resonance frequency of the output circuit of the ballast. This higher frequency current acts to preheat the filaments or cathodes. After the cathodes are preheated for a predetermined amount of time, the ballast rapidly decreases the frequency of the current. If the frequency approaches the resonant frequency of the ballast, the output voltage will increase so that the lamp ignites. If the lamp does not ignite, an electronic circuit stops the operation of the ballast.
Many electronic ballasts are controlled by a microcontroller or processor. These are sometimes called digital ballasts. Digital ballasts apply software logic to aid in lamp providing power to the lamp for starting and operation. Digital ballasts can be programmed to enable functions such as testing for broken electrodes and missing tubes before providing power for lamp starting, auto detection for tube replacement, and auto detection of tube type. In this later case, a single ballast design can be used with several different types of tube fixtures each with a different type of lamp tubes or those designed to operate at different arc currents or frequencies. Once such fine grained control over the starting and arc current is achievable, features such as dimming, and having the ballast maintain a constant light level against changing operating sunlight can be included in the digital ballast software.
Many electronic ballast used in conjunction with fluorescent lamps or other types of gas discharge lamps such as visible spectrum lights for general illumination; UV-A, UV-B, UV-C emitting lamps; germicidal lamps; and tanning lamps, by ways of example, have been provided with status or warning lights to notify persons of specific lamp operating conditions, some of which can be attributed with a predetermined maintenance issue or situation. For example, electronic ballasts have included status lights that indicate that a lamp or a plurality of lamps needs to be replaced. In other cases, electronic ballasts have included status light that indicate that the ballast is oscillating at its proper resonating frequency, or that indicate that the ballast operating power supplied voltage is within acceptable range, i.e., the input voltage is not too high or too low so that it can compromises the operation of the lamp fixture. Other electronic ballasts have included status displays that indicate the remaining life of the lamp or plurality of lamps before replacement is required. Still other electronic ballasts have status displays that provide a message indication that the lamp or plurality of lamps is operating at their proper operating electrical characteristics, such as voltage and current.
When both leads to the cathodes 110 pass through the current transducer 402 the currents from the opposing primary windings of the ballast transformer cancel out the cathode currents leaving only the arc current at the output 404 of the current transducer 402, e.g., the measured parameter is the arc current at output 404. Output 404 of transducer 402 is then used to power optocoupler 406 depending on the current circulating on the lamp 100. Optocoupler 406 (such as the type of PS2501) includes a light emitting diode (LED) 408 on the input side and a light receiving phototransistor 410 on the output side. Resistor R1 limits the current to LED 408. A major disadvantage of this detection circuit 400 is the inherent non-linearity of the diode's side of optocoupler 406. Because the output of the phototransistor 410 of the optocoupler 406 is also a non-linear device (a transistor), the optocoupler 406 generally fails to produce an accurate representation or measurement of the arc operating current of the lamp 100. Moreover, the method of detection of circuit 400 is highly sensitive to the input power 242 to the ballast 250 and as such this solution can render its representation of the state of the lamp 100 essentially useless as it inherently provides false indications of the operating status. Phototransistor 410 of optocoupler 406 acts as an analog to digital translator. In the absence of voltage provided by current transducer 402 (such as the case of a burnt lamp 100) LED 408 does not result in output from phototransistor 410. Normally the output terminal of phototransistor 410 will be pulled high via an external resistor to accomplish digital level signals. When this occurs (such as with a burnt lamp 100) the output will be pulled high when referenced to the common terminal. When the voltage provided by current transducer 402 reaches a certain threshold (such as the case of a good lamp 100) light emitted by LED 408 saturates phototransistor 410, setting the output terminal near saturation voltage of the phototransistor (which is the equivalent of a logical “0”) indicating the lamp 100 is good.
In this circuit a second optocoupler 412 with LED 414 on the input side and phototransistor 416 on the output side is positioned between the two output leads of the ballast 250 that provide lamp voltage to the cathode 110. The second optocoupler 412 is provided to detect the oscillating voltage as output by the ballast 250. For same non-linearity reasons as discussed above with regard to optocoupler 406, this also works on a very limited range input voltage range. Additionally, the output 418 of both optical isolators 406 and 412 are non-rectified outputs, switching at the ballast frequency of operation, requiring yet more additional hardware to translate those messages into truly digital indicator messages. LED 414 of coupler 412 is operated by sampled voltage from lamp cathode's 110. When the ballast 250 is not oscillating, voltage present at lamp cathode's 110 will be near zero volts.
The inventor has identified these problems and limitations and has identified a need for a gas discharge ballast and lamp fixture that provides capabilities not previously provided. The inventor hereof has succeeded at designing ballast with a built in transformer sensing capability and a system and method of adaptively monitoring, reporting and operating a gas discharge lamp fixture that is improved over the prior art. The present systems provide for a gas discharge lamp fixture that has a monitoring capability that is self-contained in the electronic ballast that can communicate to external systems or appliances the status, operating parameter values, and health of one or both of the ballast and the one or more powered lamps.
According to one aspect, an assembly for adaptively monitoring operation of a lamp fixture includes a power input interface, a ballast, and a lamp interface. The power input interface receives input power from an external power source. The ballast is coupled to the power input interface for receiving the received input power and creating lamp power between a first lamp terminal and a second lamp terminal. The created lamp power includes a terminal voltage and a variable lamp current. The ballast includes a transformer having a primary winding for receiving at least a portion of the input power. The transformer also includes a first lamp powering secondary winding coupled to the first lamp terminal and a second lamp powering secondary winding coupled to the second lamp terminal. The transformer further includes a non-lamp powering secondary winding for detecting a ballast operating parameter and transmitting a sensed ballast operating parameter value corresponding to the detected ballast operating parameter. The lamp interface is defined between the first lamp terminal and the second lamp terminal for receiving a lamp for providing light or energy responsive to receiving lamp power from the first and second lamp terminals. The sensor detects an arc current circulating through a lamp received in the lamp interface and transmits a sensed arc current value corresponding to the detected arc current. A first output interface is coupled to the sensor and provides the transmitted sensed arc current value to an external system communicatively coupled to the first output interface. A second output interface is coupled to the third secondary winding and provides the transmitted sensed ballast operating parameter value to an external system communicatively coupled to the second output interface.
According to another aspect, an assembly for adaptively monitoring and operating a lamp fixture, the assembly comprising a power input interface for receiving input power from an external power source, a ballast coupled to the power input interface receiving the received input power and creating lamp power between a first lamp terminal and a second lamp terminal, the created lamp power including a terminal voltage and a variable lamp current, a lamp interface defined between the first lamp terminal and the second lamp terminal for receiving a gas discharge lamp for providing light responsive to receiving lamp power from the first and second lamp terminals, a first sensor for detecting an arc current circulating through a lamp received in the lamp interface, the first sensor transmitting a sensed arc current value corresponding to the detected arc current, a second sensor associated with the ballast for detecting an operating parameter of the ballast, the second sensor transmitting a sensed ballast operating parameter value corresponding to the ballast operating parameter, a memory for storing a threshold arc current value, a threshold ballast operating parameter value, and computer executable instructions, and a processor coupled to the memory, the first sensor and the second sensor, the processor receiving the transmitted sensed arc current value from the first sensor, and the sensed ballast operating parameter value from the second sensor, the processor receiving from the memory and executing the computer executable instructions for performing the method of receiving and storing the sensed arc current value and the sensed ballast operating parameter value, comparing the sensed arc current value with the stored threshold arc current value, generating a lamp status message responsive to the comparing of the sensed current value, comparing the sensed ballast operating parameter value with the stored threshold ballast operating parameter value, and generating a ballast status message responsive to the comparing of the sensed ballast operating parameter value.
According to yet another aspect, an assembly for adaptively monitoring operation of a lamp fixture includes a power input interface, a ballast, a lamp interface, a sensor a clock and a processor. The power input interface receives input power from an external power source and provides lamp power to the ballast, among other components of the system. The ballast is coupled to the power input interface to receive the received input power and create lamp power between a first lamp terminal and a second lamp terminal. The created lamp power includes a terminal voltage and a variable lamp current. The lamp interface is defined between the first lamp terminal and the second lamp terminal for receiving a gas discharge lamp for providing light and or energy responsive to receiving lamp power from the first and second lamp terminals. The sensor detects an arc current circulating through a lamp that is received in the lamp interface and transmits a sensed arc current value that is the detected arc current. The clock provides for determining a current time and a memory provides for storing a threshold arc current value, and computer executable instructions. The processor is coupled to the memory, the clock, and the first sensor for receiving the determined current time from the clock, the transmitted sensed arc current value from the first sensor, and the computer executable instructions. The process executes the instructions for performing the method of detecting the receiving of a new lamp into the lamp interface, determining from the clock a new lamp time corresponding to the detecting of the new lamp, and receiving and storing in the memory a new lamp sensed arc current value. The method also includes determining an age of the lamp as a function of a difference between a current time and the stored new lamp time, comparing the current sensed arc current value and the current sensed arc voltage value with the stored new lamp sensed arc current value, and determining an end of life of the lamp as a function of the comparing to the stored new lamp arc current value. The method can also include generating an end of lamp life message indicative of the determined end of life of the lamp.
According to still another aspect, a ballast for use with a lamp fixture includes a power input interface for receiving input power from an external power source, a transformer, and output interface. The transformer has primary winding for receiving at least a portion of the input power, a first secondary winding coupled to a first lamp terminal, and a second secondary winding coupled to a second lamp terminal. The transformer creates lamp power between the first lamp terminal and the second lamp terminal that includes a terminal voltage and a variable lamp current. A lamp interface is defined between the first lamp terminal and the second lamp terminal for receiving a lamp for providing light or energy responsive to receiving the lamp power from the first and second lamp terminals. A third secondary winding detects an induced voltage and transmits a sensed ballast operating voltage value corresponding to the detected induced ballast voltage. The third secondary winding is magnetically coupled to the primary winding, and the first and second secondary windings, but is electrically isolated from each and from the lamp interface. The output interface is coupled to the third secondary winding for providing the transmitted sensed ballast operating voltage to an external system communicatively coupled to the output interface.
Further aspects of the present disclosure will be in part apparent and in part pointed out below. It should be understood that various aspects of the disclosure can be implemented individually or in combination with one another. It should also be understood that the detailed description and drawings, while indicating certain exemplary embodiments, are intended for purposes of illustration only and should not be construed as limiting the scope of the disclosure.
It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
The following description is merely exemplary in nature and is not intended to limit the present disclosure or the disclosure's applications or uses.
Before turning to the figures and the various exemplary embodiments illustrated therein, a detailed overview of various embodiments and aspects is provided for purposes of breadth of scope, context, clarity, and completeness.
In one embodiment, a ballast for use with a lamp fixture for adaptively monitoring and operating a gas discharge lamp includes a lamp power input interface, a transformer, and an output interface. The lamp power input interface is configured to receive input power from an external power source. This power source to the ballast is typically an AC power source. The transformer has a primary winding coupled to a core of the transformer for receiving all or a portion of the input lamp power as received from the lamp power input interface. The transformer also has a first and a second secondary winding magnetically coupled to the transformer core. The first secondary winding is electrically coupled to a first lamp terminal and the second secondary winding is electrically coupled to a second lamp terminal. The first and second secondary windings provide or create lamp power between the first lamp terminal and the second lamp terminal for powering a gas discharge lamp that is placed therebetween. The created lamp power has a terminal voltage and a variable lamp current that is provided at a lamp interface that is defined between the first lamp terminal and the second lamp terminal. The lamp interface is configured for receiving a lamp for activation responsive to receiving the lamp power from the first and second lamp terminals.
The transformer also includes a third secondary winding that is not coupled to either the first or second secondary windings or the first or second lamp terminals. The third secondary winding is magnetically coupled to the both the primary winding and the first and second secondary windings via the transformer core. The third secondary winding can also be referred to as a non-lamp powering secondary winding. The third secondary winding, while not electrically coupled to the lamp, provides for detecting an operating parameter of the ballast (ballast operating parameter) and transmitting a sensed ballast operating parameter value corresponding to the detected ballast operating parameter to another systems. The ballast operating parameter can be any suitable detectable parameter and in some embodiments can be an induced voltage or frequency. This third secondary winding acts as a sensor for providing or transmitting a sensed ballast operating parameter value or values from its windings that correspond to the detected induced ballast voltage. The third secondary winding is magnetically coupled to the primary winding and therefore can detect the operating condition of the primary winding. Additionally, the third secondary winding is magnetically coupled to the first and second secondary windings via the core and through their magnetic coupling with the primary winding. As such, the third secondary winding can detect operating characteristics of the first and second secondary windings that are electrically coupled to the lamp interface without itself being electrically coupled to the lamp interface. In other words, the third secondary winding provides an electrically isolated sensing of the lamp interface via the ballast transformer. The ballast includes an output interface that is coupled to the third secondary winding for providing the transmitted sensed ballast operating voltage to an external system communicatively coupled to the output interface. This output interface can be an analog or digital interface that is coupled to any type of remote or local system that is external to the ballast itself, such as another component of the lamp fixture.
Further in some embodiments, the ballast can also include a sensor for detecting an arc current circulating through a lamp received in the lamp interface. This arc current sensor can be any type of suitable sensor for detecting current through a lamp positioned in the lamp interface. For example, this sensor can be a current transducer coupled to at least one of the first lamp terminal and the second lamp terminal.
This arc current sensor transmits a sensed arc current value corresponding to the detected arc current. The transmitted sensed arc current value can be provided over a second output interface of the ballast that is also an analog or digital interface. The second output interface is second as compared to the first output interface as described above that is coupled to the third secondary winding. The second output interface is coupled to the sensor for providing the transmitted sensed arc current value to an external system communicatively coupled to the second output interface.
In another embodiment, an assembly for adaptively monitoring operation of a lamp fixture includes a power input interface, a ballast, a lamp interface, a sensor, and first and second output interfaces. The power input interface is for receiving input power from an external power source and for providing the input lamp power to the ballast. The power input interface can also provide other functions for the assembly in addition to providing lamp power to the ballast. The ballast is as described above, and can include or exclude the third secondary winding, as another form of a ballast sensor is also possible in some embodiments.
In another embodiment, an assembly for adaptively monitoring and operating of a lamp fixture includes a power input interface, a ballast, a lamp interface, a first and second sensor, a memory, a processor and computer executable instructions for performing method steps for adaptively monitoring and operating the lamp fixture.
The power input interface, a ballast, a lamp interface can be as described above. The assembly also includes a first sensor that detects an arc current circulating through the lamp and the ballast operating parameter sensor such as the third secondary winding as described by way of example above can act as a second sensor for detecting a ballast operating parameter value. A memory stores a threshold arc current value, a threshold ballast operating parameter value, and computer executable instructions. The values and instructions stored in the memory can be obtained from an external source such as via an input interface to the assembly, or the thresholds can be provided by the processor through processing of the instructions, if so programed. The input interface, where provided, can be coupled to the processor or the memory for receiving the threshold arc current value and the threshold ballast operating parameter value from an external source, such as through a data interface or message.
A processor is coupled to the memory, the first sensor and the second sensor. The processor receives the transmitted sensed arc current value from the first sensor, and the sensed ballast operating parameter value from the second sensor. The processor also receives from the memory the corresponding threshold values and executes the computer executable instructions for performing the method of operating of the assembly for adaptively monitoring and operating the lamp fixture. In one embodiment, the computer executable instructions include instructions for performing the method of receiving and storing the sensed arc current value and the sensed ballast operating parameter value. These values are compared to the corresponding threshold values as retrieved from the memory. The method than provides for one or more messages based on the result of the comparing. This can includes generating a lamp status message responsive to the comparing of the sensed current value and generating a ballast status message responsive to the comparing of the sensed ballast operating parameter value. These messages can be a variety of messages and message formats, some of which will be described by way of example below.
The third secondary winding or another form of a ballast voltage sensor can provide for detecting an operating voltage of the ballast. The processor is coupled to the ballast voltage sensor for receiving a detected ballast operating voltage, and has computer executable instructions for comparing detected ballast operating voltage to the stored ballast voltage threshold value. The processor generates a ballast operating voltage status message indicative of the comparing of the detected ballast operating voltage.
In another exemplary embodiment, as discussed above, one of the ballast operating parameters can be a frequency of the ballast. In such cases, the third secondary winding or a separate frequency sensor can provide for detecting the operating frequency of the ballast and providing such value to the processor. The memory would store a ballast frequency threshold value, such as a high and low value. The processor could use computer executable instructions for comparing the detected ballast operating frequency to the stored ballast frequency threshold value or values and then generate a ballast frequency status message that is indicative of the comparison.
In yet another embodiment, a ballast current sensor can be provided for detecting an operating current of the ballast. This can be an input current and/or an output current. As with the other parameters, the memory can store a ballast current threshold value and he processor that is coupled to the ballast current sensor receives a detected ballast operating current and compares the detected ballast operating current to the stored ballast current threshold value. A ballast operating current status message indicative of the comparing can be generated.
In still another embodiment, an additional sensor, referred herein as a third sensor, can provide for detecting a lamp voltage that is the voltage across the lamp interface when the lamp is received therein. This lamp voltage sensor transmits a sensed arc voltage value corresponding to the detected lamp voltage as either an AC or DC signal. As with the other parameters, the memory stores a threshold arc voltage value and the processor is coupled to the third sensor and receives the transmitted sensed arc voltage value. The processor uses computer executable instructions stored in the memory for performing the method of comparing the sensed arc voltage value with the stored threshold arc voltage value and generating an arc voltage status message responsive to the comparing of the sensed arc voltage value.
This lamp voltage or third sensor can be of any suitable form. In one exemplary embodiment, the lamp voltage sensor is a voltage divider circuit coupled between the first lamp terminal and the second lamp terminal of the lamp interface. The voltage divider circuit transmits an analog AC sensed arc voltage value and the processor receives the analog AC sensed arc voltage value. In some embodiments, an AC to DC converter is coupled to receive the analog AC sensed arc voltage value and generates an analog DC sensed arc voltage value. The processor receives either or both of the AC and DC sensed arc voltage values and can make comparisons and analysis thereon.
In addition to monitoring ballast and lamp operating parameters, a lamp fixture assembly as described herein can also include other lamp assembly parameters in adaptively monitoring and operating of the lamp. For example, a lamp fixture can also include a temperature sensor positioned for detecting an operating temperature of the ballast or of the lamp itself. In such embodiments, the memory would also store one or more temperature threshold values and the processor would be coupled to the temperature sensors to receive a detected ballast or lamp operating temperature. Computer executable instructions can provide for comparing detected operating temperatures to the stored temperature threshold values, and generating temperature status message resulting therefrom.
As described above, each of the sensors can include output interfaces for providing their sensed values to other components, including the processor. In this case, the processor being one of the external components or systems as compared to the ballast, each of which are components of the lamp fixture assembly. Of course, these sensor output interfaces can also be provided directly to output interfaces of the assembly itself as well as the processor within the assembly.
The assembly can also include a plurality of communications output interfaces coupled to the processor for providing messages to external systems, e.g., systems that are external to both the ballast and the other components of the lamp assembly. These can also be either analog or digital interfaces. For example, in one embodiment a first ballast output interface coupled to the first sensor for providing the transmitted sensed arc current value to the processor as well as optionally to an external system communicatively coupled to the first output interface, and a second output interface coupled to the second sensor for providing the transmitted the sensed ballast operating parameter value to the processor as well as optionally to an external system communicatively coupled to the second output interface.
An output communication interface is coupled to the processor for communicating over a coupled communication facility at least one of the generated lamp status message and the ballast status message. The output communication interface can be directly or indirectly coupled to the processor. In one example, not intending to be limited hereto, this can be a serial interface that transmits each of the lamp status message and the ballast status message are each represented as a single bit. Generally, the output communication interface can be any suitable communications interface. For example, this can include, but is not limited to, an I2C bidirectional bus interface, a phase width modulation (PCM) serial bus interface, a bi-directional RS-232 interface, an Ethernet interface, TCP/IP interface, wireless interface, Wi-Fi interface, and BlueTooth® interface, (BLUETOOTH is a registered trademark of Bluetooth SIG, Inc.).
As noted, the processor can be directly coupled to the output communication interface where the processor is configured for such, and possibly where no isolation or data communication formatting or interfacing is required with the desired communication facility. However, it is possible that the output communication interface also include an isolation module for interfacing with the communication facility and or a separate communication module for providing communication connection, protocol conversion, or data interfacing with the coupled communication facility.
In embodiments having an arc current sensor as described above, the arc current sensor can transmit an AC sensed arc current value. The processor can be coupled to directly receive the AC arc sensed current value. Additionally, an AC to DC converter can be coupled between the sensor and the processor to create a DC arc sensed current value. This DC arc sensed current value can also be sent to the processor. The processor can receive the AC and DC sensed arc current values and can be configured with computer executable instructions to generate a DC sensed arc current value and/or a generated DC sensed arc current value.
The computer executable instructions stored in the memory and processed by the processor can include additional lamp fixture processes that can enhance the adaptive monitoring and control nature and capabilities based on the herein described features. These can be of any nature and are not limited by this disclosure. As one exemplary embodiment, the processor can include executable instructions for determining a quantity of output of a received lamp, such as a quantity of light, based on one or more of the sensed ballast and/or lamp operating parameter values. For example, the present system can provide for determining a light output of a gas discharge lamp based on the sensed arc current value and the sensed arc voltage value. In another embodiment, the processor can include executable instructions for determining a percentage of lamp life remaining and generating a message including the determined percentage of lamp life remaining
In some embodiments, a clock is provided for determining a current time of various assembly or system events and time stamping of those events and the various measured values and detected events. The processor is coupled to the clock for receiving the determined current time from the clock and for making and time stamping detected events and values. Computer executable instructions are stored in the memory for performing a method that can utilize these time oriented events and measurements. For example, one method can include detecting the receiving of a new lamp into the lamp interface, and determining from the clock a new lamp time corresponding to the detecting of the new lamp. The method can also include receiving and storing in the memory a new lamp sensed arc current value and/or other lamp fixture parameters as described herein, including both lamp and ballast parameters. In one embodiment, the method can determine an age of the lamp as a function of a difference between a current time and the stored new lamp time, comparing the current sensed arc current value and the current sensed arc voltage value with the stored new lamp sensed arc current value, and based on those comparisons, determine an end of life of the lamp or at least an estimated end of life of the lamp. Then an end of lamp life message indicative of the determined end of life of the lamp can be generated over an output communication interface.
In one exemplary embodiment, an assembly for adaptively monitoring operation of a lamp fixture includes a power input interface for receiving input power from an external power source, and a ballast coupled to the power input interface receiving the received input power and creating lamp power between a first lamp terminal and a second lamp terminal. The created lamp power includes a terminal voltage and a variable lamp current as provided to a lamp interface defined between the first lamp terminal and the second lamp terminal. The lamp interface is configured for receiving a gas discharge lamp for providing light or other energy responsive to receiving lamp power from the first and second lamp terminals. A sensor detects an arc current circulating through a lamp received in the lamp interface, the sensor transmitting a sensed arc current value corresponding to the detected arc current. A clock determines a current time and a memory stores a threshold arc current value. A processor is coupled to the memory, the clock, and the first sensor and the processor receives the determined current time from the clock and the transmitted sensed arc current value from the first sensor.
The processor performs the method of detecting the receiving of a new lamp into the lamp interface, determining from the clock a new lamp time corresponding to the detecting of the new lamp and receiving and storing in the memory a new lamp sensed arc current value. The method also includes determining an age of the lamp as a function of a difference between a current time and the stored new lamp time, comparing the current sensed arc current value and the current sensed arc voltage value with the stored new lamp sensed arc current value, and determining an end of life of the lamp as a function of the comparing to the stored new lamp arc current value. From this, the processor can generate an end of lamp life message indicative of the determined end of life of the lamp. Further, or in the alternative, the processor can be configured with instructions to determine a percentage of lamp life remaining and generate a message including the determined percentage of lamp life remaining.
Of course as described above, the use of the arc current value is only exemplary, as any one or more of the lamp, ballast or lamp fixture operating parameters can be used for determination of the end of lamp life.
A monitoring and reporting system and method as described herein includes microcontroller that monitors a plurality of sensors to monitor different conditions of the electronic ballast and operating conditions of the lamp. In some embodiments, two of the parameters that provide a good indication of the lamp's operation that can be monitored, as discussed above, include:
A. arc current circulating thru the gas when the lamp is operating. A general term for a high intensity electrical discharge occurring between two electrodes in a gaseous medium, usually accompanied by the generation of heat and the emission of light. Arc current circulating thru the gas when the lamp is operating is measured by passing both cathode leads (either cathode's side of the lamp) thru a small toroidal transformer to form single turn opposing windings. In operation the opposing windings cancel out the cathode currents leaving only the arc current as the measured parameter. The toroid itself is a small ferrite core such as those used in transformer driven ballast.[2]
B. lamp voltage between these two electrodes. Because the voltage across the two opposite electrodes can reach several hundreds of volts, a voltage divider is used to scale down this voltage and make its measurable in the order of no more than 5 volts.
By monitoring this scaled down voltage, a condition called “EOL”—End Of Life (of the received lamp) can be detected by using the present disclosed lamp fixture system. Final dangerous operating conditions can happen, when the fluorescent lamp reaches the end of lifetime or at operating conditions leading to thermal instability of the lamp. As a consequence the lamp voltage becomes unsymmetrical or increases. The turn-off threshold because of exceeding the maximum lamp voltage can now be detected via the above mentioned voltage divider.
The above mentioned parameters apply to the lamp's operating characteristics. In some embodiments, the present disclosed lamp fixture system can provide for monitoring other vital functions of the ballast. These can include, but are not limited to:
Upon detection of one or more of these parameters, real time dynamic software and digital signal processing can be performed. As such, the present system can report to external devices or systems via serial communication protocols the above mentioned parameters. Sensor specific alert messages are transmitted to the remote systems and or devices.
Because the microcontroller knows the operational status via the parameter values of the ballast, lamp and or combination of both, critical feedback adaptive decisions can be then made and impressed upon the ballast. For example but not limited to:
With the present system, the reporting of the ballast and lamp health is independent of the ballast or other circuitry. In other words, even when the ballast is shut down, the status of the systems components and any causes or problems related thereto can and will continue to be reported to the remote system and or devices. Additionally, the ballast can from time to time continue monitoring the stimuli and reacting accordingly. For example, if the ballast was operating too hot, it can be re-powered after the heat decreased to safe levels.
In other embodiments, the disclosed lamp fixture system can analyze and report the amount of light or energy emitted by the lamp by analyzing the available parameters such as the arc current and arc voltage. For example, when a lamp is new and rated at 17 W, its initial arc current and arc voltage can be recorder. During the operation of the lamp, these parameters are monitored and reported over time. From this data, the percentage of “life” left on the lamp can be determined and reported.
Similarly, in some embodiments, the disclosed lamp fixture system can determined the quantity of hours that a lamp is operated and report when a replacement is due based on a comparison against a predetermined maintenance threshold for lamp hours. There are many instances, i.e. hospitals using germicidal lamps that require UV germicidal lamps replacement every 1,000 of operation.
Referring now to the exemplary embodiments as shown in the attached drawings.
The CPU 435 has four exemplary illustrated communication outputs. A first communication output is provided to an output interface 450 for interfacing with a bidirectional I2C bus. A second communication output module 452 is a PWM (phase width modulation) output interface module. In one embodiment, this interface 452 can provide a simple communication of the several states of the ballast as will be discussed in further detail below. A third communication interface 454 is provided to provide one or more digital outputs that can be utilized to communicate a message that includes various digital messages including, but not limited to, the several states of the ballast. A fourth communication output interface module 456 is a bi-directional RS-232, Ethernet or similar data communication interface that can be utilized for communicating output messages that also indicate several states of the ballast. The functions and operations of these communications output interfaces 450, 452, 454, and 456 will be explained in greater detail below.
As shown in
The thermistor 440 translates the detected operating temperature of the ballast 250 into an analog voltage that is provided to the CPU as shown. If the ballast 250 is operating outside of the temperature safety area operation of the ballast 250, the CPU can also shut down the input power 242 to the ballast 250. The operating or arc voltage between cathodes 110A and 110B (e.g., at the lamp interface 252) can be scaled down by voltage divider 422 and sampled by the A/D input pin 11 of CPU 435. It is well known to persons of the trade that the arc voltage increases as the lamp 100 ages. Therefore, monitoring of the arc voltage by the voltage divider 422 can be used by the CPU 435 to report and shut down the ballast 250 when the lamp 100 received within the lamp interface 252 reaches it's EOL (end of life).
Cathode filament 110B leads 320 are then passed thru current transducer 402. With both cathode leads 320 passing through the current transducer 402, the opposing windings thereof cancel out the cathode currents leaving only the arc current as the measured parameter in the form of an analog alternating voltage that can be provided to pin 3 (A/D input) of microcontroller 435. However, this same waveform can be rectified by network 468 and fed to microcontroller 435 pin 16 in the form of an analog DC voltage. These voltages are used to determine the actual operating current of the lamp, both dynamically and in its steady state. Microcontroller 435 can use this information as well as the lamp voltage between the cathodes (arc voltage) to calculate the exact operating parameters of the lamp at any given time. If the lamp 100 is bad or not ignited, this is interpreted by a very low lamp current measured via transducer 402 as explained above.
Further data for the operating point of the ballast 250 is obtained via sampling secondary winding S3 which is also identified as 470 (winding A1-A2). This third secondary winding S3 or 470 is not electrically coupled to the lamp cathodes but is magnetically coupled to the core 304. The voltages induced in this sensor winding 470 is provided either directly or indirectly to CPU 435 in the form of alternating (AC) voltage 472 or as a DC voltage 476 when this same waveform is rectified by network 474. These third secondary induced voltages from the core 304 of the ballast 250 can be used to determine the actual operating conditions of the ballast 250, and used among other calculations, to calculate the resonating (operating) frequency of the ballast 250. If the ballast 250 is not oscillating, the CPU 435 can immediately interpret this status can be used for reporting and controller of the ballast 250 and/or the lamp 100. The third secondary winding 470 can detect variations in the induced voltage and current form the ballast states 302A and 302B, as well as changes in the induced voltages and currents in secondary windings S1 and S2, the and the loads placed thereon at cathodes 110A and 110B, or between the two as in the lamp interface 252 and the lamp 100 received therein.
Optical and or magnetic isolation modules 445 provide bi-directional isolation to all digital and analog communication interfaces 450, 452, 478, and 456 that provide information on the operation of the ballast 250 and lamp 100 to any external systems. These isolation modules 455 to one or more of the communication interfaces 450, 452, 478, and 456 can be removed if not electrical isolation is required between the system 800 and external systems attached thereto.
An I2C bidirectional bus interface 450 was designed by Philips in the early '80s to allow easy communication between components which reside on the same circuit board. Philips Semiconductors migrated to NXP in 2006. The name I2C translates into “Inter IC”. Sometimes the bus is called IIC or I2C bus. The original communication speed was defined with a maximum of 100 Kbit per second and many applications don't require faster transmissions. For those that do there is a 400 Kbit fastmode and—since 1998—a high speed 3.4 Mbit option available. Recently, fast mode plus, a transfer rate between this has been specified. I2C interface 450 is not only used on single boards, but also to connect components which are linked via cable. Simplicity and flexibility are key characteristics that make this bus attractive to many applications. Most significant features include: only two bus lines are required; no strict baud rate requirements like for instance with RS232, the master generates a bus clock; simple master/slave relationships exist between all components. Each device connected to the bus is software-addressable by a unique address; I2C interface 450 is a true multi-master bus providing arbitration and collision detection.
An analog signal interface 478 can also be provided. The analog signal interface 478 can include a voltage that is indicative of one or more of the different states of the ballast 250 and/or lamp 100 as explained further down.
Due to the bi-directional nature of the communication interfaces and communication lines/facilities, data can be transmitted to the system 800, for example, to adjust the type of lamp 100 connected, its operating parameters, etc. making the disclosed lamp fixture system 700 a truly adaptive system. For example, as the lamp 100 ages the threshold of current for detecting a non-operating (non-ignited) lamp 100 can be adjusted.
These adjustments enable the present system 800 to be adaptive by utilizing these intelligent adapting parameter decision algorithms which can be implemented locally via microcontroller 435 or externally via serial communication port 456, or I2C bus 450, by ways of example, and not intending to be limited thereto. When the adaptive algorithm resides in microcontroller 435 and adjustments are implemented internally to CPU 435, the ballast 250 and or system 800 can be used as an adaptive intelligent stand-alone gas discharge lamp fixture powering system.
A) an operating over/under temperature detection (monitored via thermistor 440 in the form of a DC voltage determined by the resistor divider's network RT1 and R11) and reported by bit b4 EC5905 of status byte 900. As a representing example, under-temperature threshold can be set as −10° C.; over-temperature threshold can be set to +90° C.
B) Power supply under voltage detection (monitored via divider network 464) and reported by bit b2 EC3903 of status byte 900. As a representing example, under-voltage threshold can be set as +18 VAC.
C) power supply over voltage detection (monitored via resistor network 464) and reported by bit b3 EC4904 of status byte 900; over-voltage threshold can be set to +32 VDC.
D) a bad lamp 100 or lamp 100 not ignited (monitored via current transducer 402 and associated circuitry 468) and reported by bit b0 EC1901 of status byte 900; this can be determined, as a representative example, by monitoring that DC voltage output of network 468 does not fall below a minimum DC voltage threshold such as +1.5 VDC. If the measured voltage falls below this value, it is safe to assume that the lamp has not been ignited. i.e. due to a burnt filament.
E) non-oscillating or non-functional ballast (monitored via auxiliary winding 470 A1-A2 (S3) and associated circuitry 474) and reported by bit b1 EC2902 of status byte 900; this can be determined, as a representative example, by monitoring that DC voltage output of network 474 does not fall below a minimum DC voltage threshold such as +1.5 VDC. If the measured voltage falls under this value, it is safe to assume that the ballast is not oscillating.
F) End of life for lamp 100 (monitored via resistor divider 422) and reported by bit b5 EC6906 of status byte 900; this can be determined, as a representative example, by monitoring that DC voltage output of network resistor divider 422 does not exceed a maximum DC voltage threshold such as +3.75 VDC. If the measured voltage exceeds this value, it is safe to assume that the lamp is reaching its end of life. It is well known that discharge lamps increase the voltage of the cathode 110A and 110B as the lamp 100 ages in order to maintain an arc.
G) Over operating current of the ballast and/or ballast-lamp combination (monitored via EMI auxiliary winding 460 and associated circuitry 462) and reported by bit b6 EC7907 of status byte 900; this can be determined, as a representative example, by monitoring that DC voltage output of network 462 does not exceed a maximum DC voltage threshold such as +2.75 VDC. If the measured voltage exceeds this value, it is safe to assume that the ballast 250 is operating at higher than normal current draw due to a number of reasons.
H) Oscillating frequency of ballast 250 out of range (monitored via auxiliary winding 470 A1-A2 (S3) and pin 7 of microcontroller 435) and reported by bit b7 EC8908 of status byte 900. This can be determined, by measuring and monitoring the frequency presented to the microcontroller 435; say the ballast 250 is supposed to operate at 38 KHz +/−10% (arbitrarily set as an exemplary number); if the measured frequency output of winding 470 is greater than 41.8 KHz this is interpreted and reported as an over-frequency operation of the ballast. In contrast, if the measured frequency output of winding 470 is lower than 34.2 KHz this is interpreted and reported as an under-frequency operation of the ballast 250.
These are but a few of the exemplary methods and processes that can be implemented in computer executable instructions that are operated on by CPU 435 for adaptively monitoring and controller the operation of a gas lamp powering system.
Digital communication interface lines TX-RX 456 are communication lines for transmitting and receiving bi-directional information to and from the systems such as 700 and 800, for example transmission of digital bytes 900, 930 and 940. Alternatively these two lines or any two additional output lines from microcontroller 435 can be used as digital indicators to externally communicate parameter status.
Once these two parameters are fetched from memory in process 1206 and 1208, process 1210 provides that the microcontroller 435 samples value IRT (meaning current I in Real Time) in process 1212 via A/D input port RC0/AN4 and value FRT (meaning Frequency in Real Time) in process 1212 via A/D input port RC2/AN6 of microcontroller 435. The method continues in process 1214 wherein there is a comparison of the FRT to F[blst]. If FRT is lower than F[blst] it means the ballast is not oscillating or out of frequency (this can be easily detected in software). As such, it is determined in process 1216 that the ballast is bad and in process 1218 the parameters are set as B_OK=1 and L_OK=1 as stated by state 1-1 in logic state chart of
Afterwards, a process index is set in process 1310 and the microcontroller 435 proceeds to sequentially sample all analog inputs via its A/D ports in process 1308, assigning a digital value of each input to array of variables OPER_PARAM(n). As an example, OPER_PARAM(3) could correspond to DC voltage translated lamp current read via A/D port RC0/AN4 in the exemplary implementation of
Referring to
The illustrated CPU 1504 for an RFID semiconductor chip is of familiar design and includes an arithmetic logic unit (ALU) 1514 for performing computations, a collection of registers for temporary storage of data and instructions, and a control unit 1516 for controlling operation of the CPU 435. Any of a variety of processors, including at least those from Digital Equipment, Sun, MIPS, Motorola, NEC, Intel, Cyrix, AMD, HP, and Nexgen, is equally preferred but not limited thereto, for the CPU 1504. This illustrated embodiment operates on an operating system designed to be portable to any of these processing platforms.
The memory system 1506 generally includes high-speed main memory 1520 in the form of a medium such as random access memory (RAM) and read only memory (ROM) semiconductor devices that are typical on an RFID semiconductor chip. However, the present disclosure is not limited thereto and can also include secondary storage 1522 in the form of long term storage mediums such as floppy disks, hard disks, tape, CD-ROM, flash memory, etc., and other devices that store data using electrical, magnetic, and optical or other recording media. The main memory 1520 also can include, in some embodiments, a video display memory for displaying images through a display device (not shown). Those skilled in the art will recognize that the memory system 1506 can comprise a variety of alternative components having a variety of storage capacities.
Where applicable, while not typically provided on RFID tags or chips, an input device 1510, and output device 1512 can also be provided. The input device 1510 can comprise any keyboard, mouse, physical transducer (e.g. a microphone), and can be interconnected to the computer 1502 via an input interface 1524 associated with the above described communication interface including the antenna interface for wireless communications. The output device 1512 can include a display, a printer, a transducer (e.g. a speaker), by way of examples, and be interconnected to the computer 1502 via an output interface 1526 that can include the above described communication interface including the antenna interface. Some devices, such as a network adapter or a modem, can be used as input and/or output devices.
As is familiar to those skilled in the art, the CPU 435 further includes an operating system and at least one application program. The operating system is the set of software which controls the computer system's operation and the allocation of resources. The application program is the set of software that performs a task desired by the user, using computer resources made available through the operating system. Both are typically resident in the illustrated memory system 1506 that can be resident on the RFID semiconductor chip. These can include the tag reader system with computer implementable instructions stored in its memory that are accessible by and executable by the processor for performing one or more of the tag reader methods and means as described herein. Also, this can include the timing system with computer implementable instructions stored in its memory that are accessible by and executable by its processor for performing one or more of the timing system methods and means as described herein.
In accordance with the practices of persons skilled in the art of computer programming, the present disclosure is described below with reference to symbolic representations of operations that are performed by the CPU 435. Such operations are sometimes referred to as being computer-executed. It will be appreciated that the operations which are symbolically represented include the manipulation by the CPU 1504 of electrical messages representing data bits and the maintenance of data bits at memory locations in the memory system 1506, as well as other processing of messages. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, or optical properties corresponding to the data bits. One or more embodiments can be implemented in tangible form in a program or programs defined by computer executable instructions that can be stored on a computer-readable medium. The computer-readable medium can be any of the devices, or a combination of the devices, described above in connection with the memory system 1506.
The present system provides not only for the monitoring of operating parameters but also the messaging of those parameters and the results of comparisons of the parameters with thresholds that can be faults or other predetermined criteria that needs to be monitored or reported. Although there are many commercial electronic fluorescent ballasts in the market, none actually reports externally and remotely vital functions of its operating conditions.
From the foregoing disclosure, it will be appreciated that the present disclosed lamp fixture system provides numerous advantages prior lamp fixture powering systems, and is not subject to the disadvantages of the aforementioned antecedents of the disclosed lamp fixture system. The advantage features include, but are not limited to, one or more of the following for providing a remote reporting message: simple to use, well suited for economical mass production fabrication, that indicates every operating aspect of a fluorescent lamp externally connected to the ballast without physical contact with the lamp and without electrical connection with the lamp, can enable the monitoring of an existing ballast and lamp combination at a remote location and/or system; and is capable of monitoring more than one condition in need of oversight is an additional aspect of the present disclosed lamp fixture system.
When describing elements or features and/or embodiments thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements or features. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there can be additional elements or features beyond those specifically described.
Those skilled in the art will recognize that various changes can be made to the exemplary embodiments and implementations described above without departing from the scope of the disclosure. Accordingly, all matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense.
It is further to be understood that the processes or steps described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated. It is also to be understood that additional or alternative processes or steps can be employed.
