JPS58121597A - Method and circuit device for controlling illumination of gas discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method and circuit arrangement for controlling the external illuminance of a gas discharge lamp lighting installation, and in particular to a method and circuit arrangement for controlling the external illumination of a gas discharge lamp lighting installation.
PRIOR ART OF METHODS AND CIRCUIT ARRANGEMENTS BY LOAD-SIDE CONTROL USING A CONTROLLED IMPEDANCE CONNECTED BETWEEN A WINDING AND A GAS DISCHARGE LAMP Various novel techniques have been proposed for controlling the output illuminance level of a gas discharge lamp. ing. An example of a device for dimming a lamp in response to changes in selected illuminance levels or a secondary light source, such as natural sunlight, is disclosed in U.S. Pat. No. 4,197,485.

However, this technique has the drawback of reducing the net efficiency (Lunon output/Watts input) of the lighting device and at the same time requiring expensive and complex circuitry to provide sufficiently effective dimming.

An alternative technique used to increase the overall efficiency in a dimmer is to convert the mains frequency to a high frequency. U.S. Patent Nos. 4,207,497 and 4-2074.9
No. 8 discloses this technique.

The assignee of the present invention is Japanese Patent Application No. 57-1.25931 (U.S. Patent Application S, N, 286770: July 1981)
(filed on May 27, 1981) and Japanese Patent Application No. 1981-77￥7p1 (U.S. Patent Application S, N, 309260: 1981-1)
Currently applying (filed on October 7th). These are associated with control circuits that function for conventional electromagnetic ballasts to control the output illuminance level of gas discharge lamps. The control devices of these applications are intended for use in previously designed lighting systems, either before or after they are marketed. Standard electromagnetic ballasts are used here for two-lamp or four-lamp lighting installations, respectively. For accurate and efficient operation of many electromagnetic ballasts encountered, the control circuit has a circulating inductor connected in parallel to the control impedance. A method and circuit arrangement for controlling the output illuminance level of a lamp is directed.

The present invention is directed to a method for simple and efficient illuminance control of gas discharge lamp vessels operating at mains frequency. Although the illuminance control performs dimming from 10 to 1-1, a high power factor is maintained, and in addition to a good crest factor, a small lamp current and a small ballast loss can be obtained. Illumination control is provided by a time interval controlled impedance connected in series between the primary winding of the electromagnetic ballast and the lamp. A current path is formed between the power supply and the lamp during a portion of the alternating current signal. The controlled impedance is substantially non-conducting during a portion of the alternating current signal. Such an arrangement does not substantially reduce the cand heating voltage to be supplied to the lamp since the circuit is connected to the power supply. With the method and circuit arrangement according to the invention, illuminance control is possible in the range from 100% to 10% of the total illuminance.

As mentioned above, when standard electromagnetic ballasts manufactured in large numbers are introduced, it is necessary to wind a circulating inductor for proper and efficient illuminance control of the lighting device.

The invention forms a unit that includes both an electromagnetic ballast element as well as an illumination control element. As a result, the circular inductor can be omitted. More importantly,
Since one electromagnetic ballast device can be used for both functions, additional electromagnetic components as part of the illumination control circuit can be omitted. Furthermore, in the case of a standard electromagnetic ballast, the magnetic circuit is not limited in terms of connection for illuminance control. The possibility of connecting a suitable circuit for illumination control at any point within the electromagnetic element is given as an "acidification effect" of this unit. The figure illustrates a conventional fluorescent lighting system useful as a basis for discussing the novel features of the present invention. A standard electromagnetic ballast 10 with multiple windings wound on an iron core drives gas discharge (fluorescent) lamps 12 and 14 connected in series. As shown in FIG. 1, ballast 10 includes lead pairs 20, 22 and 24, each derived from a winding within ballast 10.

The ballast still has a starting capacitor 26 and a power factor correction reservoir series capacitor 28. In operation, lead pair 22 provides heating current to the candos of lamps 2 and 14, and power is provided between leads 20 and 24 to ignite the lamps in series. Ballast 10 is connected to an AC power source through leads 30 and 32.

FIG. 2 shows an embodiment of the gas discharge lamp illuminance control device according to the present invention. Although a conventional fluorescent lamp is used as a specific example of a gas discharge lamp for ease of explanation, other gas discharge lamps including mercury vapor, sodium vapor, metal halides, etc. are applicable to the present invention. It is clearly understood that this is possible. Although only two fluorescent lamps are shown in the embodiment, the invention can be easily extended to two or more fluorescent lamps.

The operation of the illumination control device of the present invention is disclosed in sufficient detail below. However, the patent application filed in 1983 by the same applicant
No. 125,931 (U.S. Patent Application No. 286,770:198
(filed on July 27, 1981) and Japanese Patent Application No. 1987-/October 727 (U.S. Patent Application No. 309,260: October 7, 1981)
Both applications disclose in detail the operation of modular illumination control systems similar to the present invention. While the above two applications describe modular controlled lighting systems to be used in conjunction with conventional electromagnetic ballasts, the present invention, on the contrary, describes integrated control circuits and electromagnetic ballasts to be used in place of standard electromagnetic ballasts. Directly oriented.

A first embodiment of integrated ballast controller 40 connects fluorescent lamps 12 and 1 via IJ-wire pairs 20, 22 and 24.
4 is shown in FIG.

The integrated ballast includes electromagnetic parts similar to those shown in ballast 10 of FIG. 1, except for an additional winding 42 which provides a low voltage for control of the lighting device. The electromagnetic part or primary winding 44 of the transformer is connected to the lead wire 3 as in the ballast of FIG.
0 and 32 are connected to the AC power supply. integrated ballast 40
further includes the above-mentioned lighting capacitor 26 and series capacitor 28. Secondary windings 46, 48 and 50 are connected to fluorescent lamps 12 and 14 through lead wire pairs 20.degree. 22 and 24, respectively. lamps 12 and 1
The energy to heat the cathode 4 is supplied from the lead wire pair 22 through the winding 48. The voltage across lead pair 22 is a result of the turns ratio of winding 48 to primary winding 44;
Typically it is 3.6 volts.

Control of the power supplied to gas discharge lamps 12 and 14 is accomplished using control circuit 60 and control impedance 60. Winding 42 is formed with fewer turns than primary winding 44 to achieve voltage step-down. normal 130v
In the system, the winding 42 has approximately 18 ac of current between the output leads.
It is preferable to force V. This 18V signal serves as a power source for control circuit 60.

Controlled impedance 62 forms the main current conduction path from primary winding 44 to one of the secondary windings. Control circuit 60 provides time interval controlled drive signals to control electrodes of impedance 62. In effect, control circuit 60 acts to drive impedance 6 from a non-conducting state to a conducting state or from a conducting state to a non-conducting state during a controlled portion of each half-cycle of the AC power supply voltage.

The control impedance 62 is preferably a control switch capable of forming either an open circuit or a closed circuit between the main current paths depending on the IfIJ control signal applied to its control electrode. Control impedance 6
It will be appreciated that the condition of 2 (conducting or non-conducting) is determined by whether lamp current is flowing through the controlled impedance.

When the controlled impedance 62 is conductive, a series circuit is formed between the ballast and the lamp that provides operating current to the lamp. When impedance 62 is non-conducting, only heating current is supplied to the lamp cathode, as described below.

The gate electrode 64 of the control impedance 62 is connected to the control circuit 6
Connected to the output of 0. If there is no actuation signal on the gate I, the TRIAC 62 is connected to the primary winding 4.
4 and the lamp. When an activation signal is applied to the gate, the TRIAC turns on, thereby presenting a low impedance (i.e., conduction) between the secondary winding and the lamp. Thereafter, the TRIAC 62 remains conductive until the current is below a predetermined extinction current.

The TRIAC 62 conducts in both directions in response to a trigger, but the TRIAC turns off every half cycle of AC when the current drops below the extinction current during a change in direction of AC current. In a suitable embodiment, TRIAC 62 is retriggered every half cycle of the power supply signal.

By changing the delay before 1.1 no Ichiga occurs,
It is possible to control the conduction of the TRIAC 62 and thus the total power delivered to the lamp each half cycle.

FIG. 3 shows another integrated ballast control device 40 connected to fluorescent lamps 12 and 14 via lead pairs 20, 22 and 24. This circuit is similar to the second one except that the control circuit 6° and the controlled impedance 62 are connected between the primary winding 44 and one of the pair of leads 2o to the lamp 12.
It is similar to the figure. The operation of integrated ballasts 40 and 40' is similar as described below. Integrated ballast 40 or 40
In either case, when controlled impedance 62 is conductive, electrical power is supplied to lamps 12 and 14 through the controlled impedance. Power is still supplied to the lamp during non-conduction of the controlled impedance, but its magnitude is much smaller than the power supplied during conduction;
It simply heats up the cathode while waiting for the next conduction state of the impedance.

The control circuit 60 of FIGS. 2 and 3 includes a lead pair 66 to be connected to the photocell for purposes that will be clearly understood from the discussion hereinafter disclosed regarding the operation of the integrated ballast.

The benefits expected from the operation of integrated ballasts and control circuits are described in both of the above-mentioned applications, Japanese Patent Application No. 57-1.25931 (U.S. Patent Application No. S, N, 286,770);
7'7;'7λ/ (U.S. Patent Application S, N, 309,
260), it can be clearly understood. The subject matter of both these applications is disclosed by reference.

Referring to FIG. 4, a block diagram illustrating the current control function of control circuit 60 is shown. Generally speaking, the control circuit consists of two feedback loops. The first loop controls the lamp current within the range of the IJ meter, and the second loop controls the intensity of illumination. The first loop sets the lamp current to a specific value. This first loop is illustrated by the dashed connection and has a controlled impedance 62
includes monitoring the lamp current by summing the current flowing through the main current path of the lamp. The lamp current is converted to a voltage by a current to voltage converter 70 resulting in a voltage vc proportional to the current monitored at the cathode of impedance 62. This signal is the first function of lamp current and is the parameter used by the circuit for current control. A second feedback loop compares the photocell output to a reference signal. As shown in FIG. 4, the first self 2 is positioned across the irradiance of the gas discharge lamps J2 and 14 and generates a signal proportional to the output illumination level of the lamps and the illumination level of the adjacent surroundings. .

Comparator 74 converts the output of the photocell to a reference signal VRE generated either internally or externally (not shown).
Compare with F. The output of comparator 74 is connected to integrator 76. This integrator 76 functions to attenuate changes due to ambient light fluctuations and others. To limit the output signal of integrator 76 within the operating range of a given lamp configuration, the output of the integrator is connected to a signal limiter 78. The first and second control signals generated by the first and second loops are respectively connected to a summing circuit 80 which generates a difference signal VERROR. Obviously, if no modification is required, the first and second control signals are equal and VE
RROR will be equal to zero. The difference signal from summing circuit 80 is connected to an integrating circuit 82 for integrating the difference signal over time. The integrated signal is transmitted through the controlled impedance 62
is connected to a voltage controlled one-shot circuit 840 input that controls the firing of the . The output of integrator 82 advances the timing of voltage controlled one-shot circuit 84. This one-shot circuit in turn advances the firing of control impedance 62.

The control circuit operates with a positive error between the set point and the lamp current.
1-V□□. It can be best explained by assuming that □ exists. This positive error causes the output of the integrator circuit 82 to rise with time and advances the timing of the voltage control one-shot 84. This also acts to accelerate the triggering of control impedance 62 in the voltage cycle, increasing the current introduced into lamps 12 and 14. The difference signal from the adder circuit 80 is zero, that is, V
In the case of ERROR-0, the output of the integrator circuit 82 stops increasing and the timing of controlled impedance firing between voltage cycles remains unnecessary.

To explain the practice of the present invention to those skilled in the art, FIG. 5 shows a circuit diagram of a specific embodiment of a two-fluorescent lamp array for an integrated modular lighting control circuit 40. This description deals with the embodiment of the invention featured in FIG. It should be understood that the embodiment of FIG. 3 can be easily adapted to some variations in electrical connections. The control impedance 62 is a TRI AC impedance whose main current path is connected between the gas discharge lamp lead wire pair 24 and the current sensing resistor 86.
It consists of

Winding 42 is connected to a diode bridge 90 that includes diodes D1-D4. This diode bridge provides rectified output to control circuit 60 and provides 60H7 synchronization to the one-shot circuit as described above. transistor 92
and resistor 94 is connected to a predetermined voltage, for example, I, as a control circuit power supply.
Forms a series regulator for OV. Photocells, not shown, are connected in a bridge connection that includes resistors 96, 98 and 100 and are connected to lead pair 66. The reference value of the bridge connection reservoir of the photocell can be set mechanically by a shutter mechanism that covers the photocell from illumination by the lamp or electrically by adjusting the bridge resistance itself.

The integrating circuit 76 connected in the second control loop has a resistor 10
2, formed by capacitor 104 and operational amplifier 106. The output signal of the integrating circuit is resistor 1.08.11
0 and 112.

This resistor network forms a signal limiter 78. The upper and lower limits of limiter 78 are resistors 108 and 1, respectively.
Set by 10.

21- The output of limiter 78 is compared to a voltage representing a half cycle of lamp current as the output of the second control loop described above. This first control loop output induces a signal proportional to the current flowing in the main current path of the TRIAC 62, and the current -
This is obtained by converting this current signal into a voltage using a voltage converter 70. Converter 70 is transistor 114
Contains.

The difference between limiter 78 and current-to-voltage converter 70 is obtained as the combined output of summer 80, as described above.

This difference is provided to an integrator circuit 82 that includes a resistor 116, a capacitor 118, and a differential amplifier 120.

Integrated circuit 122 forms a dual timer disposed in two one-shot circuits. The first one-shot circuit is triggered by a zero crossing of the power supply voltage and is controlled by the output of the integrator circuit 82. The second one-shot is triggered by the tail of the output of the first one-shot relative to the break. The output of the second shot is the trigger gate 6 of the TRIAC62.
It is connected to the base of transistor 124 used for 4.

22-It should be emphasized that while preferred embodiments of the invention and specific structures and structural interrelationships of the components are shown herein, many embodiments of the invention are possible and It will be apparent that many variations are possible in the disclosed embodiments without departing from the spirit of the invention. Therefore, it is to be clearly understood that the foregoing facts are to be construed as merely illustrative and not limiting of the present invention.

[Brief explanation of the drawing]

FIG. 1 shows a two-lamp fluorescent lighting device using a conventional electromagnetic ballast. FIG. 2 shows an embodiment of the illuminance control device according to the present invention. FIG. 3 shows another embodiment of the illuminance control device according to the present invention. 4 shows a block diagram of a control circuit of an illuminance control device according to the present invention. FIG. 5 shows a particular embodiment of the invention. Correspondence of main reference symbols in the figure: 10: Electromagnetic ballast 12.1.4. : Gas discharge lamp 20.22, 24: Lead wire pair 26: Capacitor 28: Capacitor 30.32: Power lead wire pair 4
0: Integrated ballast 60: Control circuit 62: Control impedance (TR1 [AC) 70: Current-voltage converter 7
2: Photocell 74: Comparator 76: Integrating circuit 78: Limiter - 80 = Adder

Claims (1)

[Scope of Claims] (1) A circuit for controlling the output illuminance of a gas discharge lamp lighting device, the circuit comprising: an electromagnetic ballast device for supplying power to at least one gas discharge lamp; a ballast arrangement and a control impedance connected between said at least one gas discharge lamp, and a circuit arrangement for controlling conduction of said control impedance to cause said gas discharge lamp to emit light, said circuit arrangement comprising: a control impedance connected between said at least one gas discharge lamp; a circuit arrangement configured to respond to deviations from a predetermined value; (2. The circuit of claim 1, wherein the circuit arrangement includes a timing device that is started by the start of each half-cycle of the AC power input signal, and (3) The circuit of claim 2, wherein the controlled impedance is TRIA, C. (4) Claim 1. 5. The circuit of claim 4, wherein the lighting device includes a pair of gas discharge lamps connected in series. (6) A circuit as claimed in claim 4, wherein the ballast device has a magnetizing current. 7) The circuit according to claim 1, wherein the circuit arrangement includes first and second control loop circuits. , the first control loop circuit functions to control the lamp current within a limiter, and the second control loop circuit includes a signal proportional to the illuminance level of the lamp and a reference signal, and a reference signal may be present. configured to function for comparison with some other drive signal. (8) The circuit according to claim 3, wherein the TRIAC has a main current path connected between one output of an electromagnetic ballast device and a gas discharge lamp;
is configured to be responsive to the drive signal to provide current continuity between the ballast device and the ramp initiator during at least a portion of each half cycle of alternating voltage. (9) A method for controlling the illuminance of a lighting device using at least one gas discharge lamp, comprising: providing an alternating current power supply; connecting a primary winding of a transformer; connecting a controlled impedance in series between said secondary winding and a first connection of said gas discharge lamp; and by means of a circuit arrangement responsive to deviations of the lamp current from a predetermined value. The method comprises the steps of: controlling conduction of the controlled impedance. (10) In the method according to claim 9, the total illuminance of the portion illuminated by the lighting device is detected, and the conduction time of the controlled impedance is adjusted in order to keep the total illuminance constant. Said method. 11. The method of claim 9, wherein the length of conduction time is adjusted during each half cycle of the power supply signal. (12) The method according to claim 9, in which the controlled impedance 14. The method of claim 9, wherein the power supply signal has a predetermined conducting state and a non-conducting state. The method for controlling the length of time during which the control impedance is maintained in a conductive state. (15) A device for controlling the output illuminance level of a gas discharge lamp on the load side, comprising: an AC power source; and an AC power source connected to the AC power source. a transformer arrangement for powering the gas discharge lamp, the transformer having a primary winding and a plurality of secondary windings, connected between the secondary winding and at least one of the gas discharge lamps; 5- a device for controlling conduction of said controlled impedance in response to changes in lamp current, said at least one gas discharge lamp being in series with said secondary winding; (16) The device according to claim 15, which is configured to perform load-side control of the output illuminance level of a gas discharge lamp electrically connected to the device.
The controlled impedance is made of TRIAC. (17) In the device according to claim 16,
A current detection device is connected to the cathode of the TRIAC. (18) In the device according to claim 17,
The current sensed at the cathode of the TRIAC is connected to a circuit arrangement that provides a current regulation signal used to regulate the lamp current. (19) In the device according to claim 18,
The transformer device has a laminated core to reduce magnetizing current. (2. In the device according to claim 15,
6- the device for controlling conduction includes first and second control loop circuits, the first control loop circuit functioning to control the lamp current within limits of the limiter; Compare with other drive signals that have /ζ
something that is configured to function as intended. (2. The device according to claim 16, wherein the TRIAC has a main current path connected between the output of the transformer device and the gas discharge lamp, and
The IAC is responsive to the drive signal to force current conduction between the transformer device and the lamp during at least a portion of each half cycle of each AC voltage.