Patent Application
20130057154
The present disclosure is related devices and methods for use with rapid start ballasts for fluorescent lamps to provide illumination intensity control.
Rapid start fluorescent lamps are very popular for lighting purposes, especially in offices, work places, business and homes. Rapid start ballasts offer some technical advantages over the instant start ballast, such as an increase in lamp life expectancy because the turn on process of the rapid start ballast causes less deterioration in the lamps. Rapid start ballasts achieve the lighting of the lamps by heating the filaments in the lamp terminals using a current so that an electrical flow may begin through the fluorescent tube.
Ballasts, such as rapid start ballasts, control the intensity of the electrical flow through the lamp at a nearly constant value and allow an intense luminosity which is close to the nominal power of the lamps used.
Some rapid start ballasts are designed to allow control of the illumination intensity using elements such as light sensors, presence sensors, or other devices outside of the ballast. The aforementioned is performed by incorporating these elements to regulate the electrical flow of the lamp, where the electrical current affects the luminous intensity of the lamp.
In one conventional approach, a rapid start ballast has an entry port to turn on or off selected lamps in an array of lamps. By selectively turning on or off ones of the lamps, the ballast controls the total luminosity of the array of lamps. However, this approach changes the lighting pattern of the array of lamps, losing uniformity in the intensity in the illuminated area.
In another conventional approach, a rapid start ballast provides control of illumination intensity though use of a frequency variation element. In one example, a rapid start ballast contains an element that regulates the current which flows through the lamps with a frequency variation technique. The frequency variation technique moves an operating frequency closer or farther away from a resonance frequency to control the luminous intensity of a lamp. Another conventional technique includes changing the relation of the current amplitude in the two half cycles of a sinusoidal waveform, regulating the current and the luminosity.
There is a need for an efficient and effective way to provide luminosity control for a fluorescent lamp installed with a rapid start ballast.
Various embodiments include a device for use with a rapid start ballast to allow for luminosity control of one or more lamps supported by the rapid start ballast. Various embodiments also include methods for controlling the luminosity of such lamps.
One example embodiment includes a device to dim the light of a lamp supported by a rapid start ballast. The device includes a control mechanism to dim the intensity of the light. The control mechanism executes a luminosity adjustment in response to, e.g., the external light detected by an illumination sensor in the area, a presence detected by movement sensors, a selection element for manual dimming, and/or the like. The device can be retrofitted to a rapid start ballast that was originally not designed for dimming. Thus, some embodiments include a device, separate from the ballast, which can be installed with the ballast (as described further below) to control luminosity of a fluorescent lamp.
Further in this embodiment, the example device includes a magnetic element with a current divisor array and with exit ports in communication with the current divisor array. The current devisor array can be used to select various combinations of ports which correspond to two or more levels of light intensity in the fluorescent lamps. Further in this example, the ballast provides the lamps with an electrical flow of proportions no greater than one (but less than one when dimmed) with respect to the nominal capacity of the lamp. Such electrical flow can be achieved by providing an appropriate number of turns in the magnetic element for each one of the individual ports.
The example device further includes a commutable element to select exit ports of the magnetic element, where a set of exit ports corresponds to a respective dimming level, and where at least two different sets of ports can be selected.
In one aspect, embodiments of the disclosure control the lighting level in rapid start ballasts for fluorescent lamps that were not originally designed for dimming.
The aforementioned is achieved by using a commutable transformer with a relation in its coils that changes the charge to the ballast, in relation to the current of the transformer, and while also maintaining current sufficient for turn on of the filaments of the lamp. The luminous intensity corresponds to the transformer's own current, which is commutable, and the luminous intensity may be adjusted in or more steps.
In another aspect, embodiments of the disclosure incorporate characteristics which contribute to energy savings in illumination systems without making changes to the electrical circuits of the ballast or the lamps.
In one example, the device can be connected to light and presence sensors, manual or automatic switches, or other means to control the intensity of light as appropriate for a desired application.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
Referring to
It should be noted that while the examples of
The ballast lines 102 which supply the terminals 111a of lamp 111 in
The other state of device 210 is when relay R1 is in electrical contact with terminal b. In this state one of the terminals 103 of the lamp 112 comes in contact with the coil L4 through the relay R1. In this state, the magnetic interaction of coils L3 and L4 causes a current reduction. In another aspect, some current from device 210 is shunted to terminal 103, thereby decreasing the current that flows serially through lamps 111, 112. The decrease in current results in a dimming of lamps 111, 112.
The amount of current reduction depends, at least partially, on the number of turns in coils L3 and L4. Generally, the reduction proportion may be according to equation 1.
Level of reduction=L3 turns/sum(L3 and L4 turns). Eq. 1
Device 210, therefore, provides two luminosity settings. One setting is at 100% of the level which would normally be supplied by ballast 101 (i.e., the level that would be provided by the set-up of
The device 210 has a dimming control unit C1, which has ports 211-213 which may be connected to one or more input devices, including, e.g., motion sensors, light sensors, manual inputs, and the like. Signals at ports 211-213 may control a selection of a luminosity level for lamps 111, 112. In one manual example, a human user selects a brighter or dimmer state. In one automatic example, a light sensor adjusts a luminosity depending on a level of ambient light. In another automatic example, a motion sensor selects the higher luminosity setting only when it detects a person in the room. However, the scope of embodiments is not limited to the examples provided above. Various embodiments may receive input control signals from any type of device now known or later developed and may, therefore, be controlled in any desirable manner.
The control unit C1 is powered by an electrical source 215. Control unit C1 has an output 216 that physically controls relay unit R1 to be in contact with port a or b to select the dimming intensity in the lamps 111, 112.
The electrical supply 215 for the device 210 is connected to terminals J3A and J3B to a transformer T1 to step down the voltage. The stepped down voltage is then rectified by rectifier unit P1 and filtered through a capacitor C3. In this manner MP1 unit is energized by a regulated DC voltage.
Microcontroller unit MP1 has the function of processing signals from ports 211, 212, and controlling relay unit R1 in response thereto. MP1 includes a logic circuit that executes software and/or firmware to process signals from ports 211, 212 appropriately. MP1 receives signals from ports 211, 212, determines an appropriate luminosity setting, and actuates relay R1 to select the luminosity setting. During actuation of the relay R1, MP1 causes a reduction effect of at least one of the capacitors C1 and C2, which in turn allows for a commutable reduction, therefore the transitory peaks in the relay unit R1 when it connects to the exit line of the ballast in contact with the terminal of the lamp unit 3 in terminal J4A to the coil unit L4.
The coil units L3 and L4 work as a current divider by means of a magnetic effect. In another way of viewing the operation of device 210, the selection of a port a, b by relay R1 changes the current paths within device 210, thereby affecting the amount of current that flows through lamps 111, 112. When relay R1 selects port a, coils L3 and L4 are connected to form a loop, and the maximum allowable current flows through lamps 111, 112 at ports J4B, J4C (no current flows at port J4A).
When relay R1 selects port b, some of the current is shunted via port J4A to terminals 103. In this state, less than the maximum allowed current flows through lamps 111, 112. Thus, device 210 acts as a current divider, in one aspect, by dividing the current among sets of ports including 1) ports J4B and J4C and 2) J4A, J4B, J4C.
The coil units L1 and L2 are designed to maintain the heating current in the filament (not shown) of lamp 111 connected at terminals J4B and J4C. Inductor L1 is the primary winding, and inductor L2 is the secondary winding, connected to terminals J4D, J4E. Ballast 101 supplies current to terminals J4D, J4E, and the transformer formed by L1 and L2 adjusts the amount of current according to the respective numbers of turns in L1 and L2.
In some embodiments, MP1 of device 210 turns the lamps 111, 112 on at 100% of the ballast power to obtain an efficient lamp switch on, regardless of the signals from the motion or light sensors, manual or automatic manipulation. After a sufficient time, the luminosity setting may be changed to less than 100%, if instructed.
Controller C2 receives input signals from ports 411-413, which may be same as or similar to the signals described above with respect to ports 211-213 of
Control unit C2 operates in a manner similar to that discussed above for control unit C1 at
In
When relay R3 selects port e, the two luminosity settings (provided by the selection at relay R2) are the same as described above with respect to
When relay R3 selects port f, two luminosity setting can be achieved by switching relay R2. When relay R2 selects port c, the luminosity setting is about 100%. When relay R2 selects port d, the reduction in current through the lamps 111, 112 can be calculated using equation 2 below.
Level of reduction=L3 turns/sum(L3, L4 and L5 turns). Eq. 2
In block 510, the ballast provides a first electrical current to the luminosity control device. The luminosity control device adjusts the first current to provide a second current to the lamps in block 520. Blocks 530 and 540 illustrate one example technique to provide the second current to the lamps.
In block 530, the first current is passed to an inductive current divisor array. An example of an inductive current divisor array is shown in
In block 540, the commutable element selects between the first current path and the second current path. The first current path corresponds to a first luminosity setting (and a first level for the second current), and the second current path corresponds to a second luminosity setting (and a second level for the second current). Generally, a smaller value for the second current corresponds to a lower luminosity setting. In some embodiments, such as that shown above in
In block 550, the second current is used to heat an electrode in at least one of the lamps. In some embodiments, the electrode is heated, even during normal operation.
The scope of embodiments is not limited to the specific actions shown in
Various embodiments provide one or more advantages over the configuration shown in
In some instances, a retrofit of one of the above-described devices to a conventional lamp does not employ additional wiring for control, and its connection can be made in a simple and quick manner. Thus, in such instances, a relatively small investment can be made to adopt energy savings in an existing illumination system for the control of fluorescent lamps with rapid start ballasts. This can be especially true where the cost of ballast is higher than the cost of a retrofitted dimmer device.
In some embodiments, such as those shown in
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
