JPS62145697A - High voltage sodium lamp burner - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lighting device for lighting high-pressure sodium lamps.

2. Description of the Related Art As a lighting device for lighting a high-pressure sodium lamp using an AC power source, a lighting device using magnetic circuit components such as a choke coil or a one-cage transformer is most commonly used. However, when high-pressure sodium lamps, particularly high-color rendering type high-pressure sodium lamps, are lit with these lighting devices, the color temperature of the lamps varies between individual lamps due to manufacturing variations in the lamps.

As a conventional example of a lighting device for reducing variations in color temperature of lamps, an electronic ballast that performs constant tube voltage control using a thyristor phase control method shown in FIG. 6 has been reported (for example, Tsutomu Shiojiri et al.: Proceedings of the National Conference of the Illuminating Society of Japan in 1988, page 51).

In Fig. 6, 1 is an AC power source, 2 is a first choke coil, 3 is a second choke coil, and 4 is a high-pressure sodium lamp.The AC power source 1 is connected to the high-pressure sodium lamp 4 via the choke coil 2.3. It is designed to turn on the light by passing an electric current through it. Furthermore, 6 is a DC power supply, 6 is a control means, 7 is a lamp voltage detection means, and 8 is a bidirectional thyristor with a control terminal (hereinafter referred to as thyristor). DC power supply 6
is connected at its input end to the AC power source 1, and is connected to supply a DC output to the control means 6. The lamp voltage detection means 7 has input terminals connected to both ends of the high-pressure lamp 4, and is connected so as to output a signal corresponding to the lamp voltage to the control means 6.

Furthermore, the li control means 6 is connected to control the control angle of the thyristor 8 according to the output signal of the lamp voltage detection means A, and the thyristor 8 is connected to both ends of the choke coil 2.

The operation of the conventional example shown in FIG. 5 will be explained below.

When the AC power source 1 is turned on, current flows through the choke coil 2.3 to the high-pressure sodium lamp 4, turning it on.

The lamp voltage during lighting is detected by lamp voltage detection means 7, and a signal corresponding to the mi-lamp voltage is output. In response to this signal, the control means 6 causes the conduction period of the thyristor 8 to be shortened when the lamp voltage is high, and to become long when the lamp voltage is low. The current flowing bypassing the choke coil 2 is controlled, and a control signal is output to the thyristor 8 so as to keep the lamp voltage constant.

Problems to be Solved by the Invention In such a conventional lighting device, lighting can be performed so that the lamp voltage remains constant.

However, in high-pressure sodium lamps, even if the lamp voltage is constant, the color temperature varies depending on the lamp power and lamp current, so in conventional lighting devices, it is difficult to sufficiently reduce the variation in color temperature between individual lamps. The problem was that it was not possible.

The present invention has been made in view of the above, and provides a lighting device that has a simple configuration and is capable of lighting high-pressure sodium lamps while suppressing variation in color temperature between individual lamps within a small range. The purpose is to

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has a lamp voltage detection means, a lamp current detection means, and an output of the lamp voltage detection means and an output of the lamp current detection means, respectively. The apparatus includes a calculation means for multiplying the color temperature by a predetermined coefficient and then adding the result, and a control means for controlling the output of the calculation means to be constant.

As a result of our research, the present inventors found that in high-voltage SL-IJ lamps, when the lamp voltage is held constant, the higher the lamp current is, the higher the color temperature becomes; The color temperature tends to be high, and in order to sufficiently reduce the variation in color temperature between individual lamps, the lamp voltage and lamp current are each multiplied by a predetermined coefficient determined for each type of lamp. We found that it is sufficient to control the sum of multiplication results to a constant value.

The present invention controls the lighting of a lamp based on the above results.The lamp voltage and lamp current are detected by the above-mentioned means, and the output of each detection means is multiplied by a predetermined coefficient, and the result of these multiplications is calculated. can be controlled so that the sum is constant.

Therefore, it is possible to reduce the lamp current for a lamp with a high lamp voltage and increase the lamp current for a lamp with a low lamp voltage, thereby suppressing variations in color temperature between individual lamps within a small range.

Embodiment FIG. 1 is a basic circuit configuration diagram showing an embodiment of a lighting device for a high-pressure sodium lamp according to the present invention. In Figure 1,
1 is an AC power supply, 2 is a first choke coil, 3 is a second choke coil, 4 is a high-pressure sodium lamp, and 6 is a DC power supply, which is a full-wave rectifier circuit consisting of diodes 9, 10, 11, and 12. Current limiting resistor 13 and constant voltage diode 14
It rectifies the output of the AC power supply 1 and outputs DC. 7 is a lamp voltage detection means, and the voltage on the negative side is high.) A transformer 16 connected in parallel with the IJum lamp 4.
, current limiting resistor 16, diode 17, and capacitor 1
8, and outputs a DC voltage corresponding to the lamp voltage from both ends of the capacitor 18.

Reference numeral 19 denotes a lamp current detection means, which is composed of a transformer 2Q whose negative side is connected in series with the high-pressure sodium lamp 4, a current-limiting resistor 21, a diode 22, and a capacitor 23, and detects direct current according to the lamp current. voltage to capacitor 2
30 Output from both ends.

24 is an arithmetic means, and includes resistors 25, 26, and 2A.

2B, 29.30 and an error amplifier 31, the output of the lamp voltage detection means 7 and the output of the lamp current detection means 19 are respectively inputted via resistors 26.25'ii, and the error amplifier 31 To keep the color temperature constant, the detection means 7 and 19 are multiplied by coefficients determined by the resistance values of the resistors 26, 26, and 29, respectively, and then added, and the output voltage of the DC power source 5 is divided by the resistors 27.28. The difference between the two voltages is amplified and output. 6 is a control means, which includes diodes 33, 34, 35 and resistors 36, 37, 38°3.
9+40.41, capacitor 42.43, transistor 44, and unijunction transistor (hereinafter referred to as U
JT) 45 and a transformer 46, the output of the DC power supply 5 is input as a power source, the output of the calculation means 24 is received by the transistor 43, and a voltage corresponding to the output voltage of the calculation means 24 is applied to the capacitor 42. and accumulates in capacitor 4
The capacitor 43 is charged by the voltage of 2 through the diode 33 and the resistor 37, and the voltage of the capacitor 43 becomes UIT.
When the peak point emitter voltage Vp of 4s is exceeded, UTT4
5 conducts, and the primary II of the transformer 46 passes through three resistors.
A current is passed through II, and a trigger pulse is output from the secondary 11111 of the transformer 46 via the resistor 40 and diode 36. This trigger pulse is generated every half cycle of the AC power supply 1 with a phase determined by the time constant of the resistor 37 and the capacitor 43 and the voltage of the capacitor 42. Resistance 38.
41 is provided to ensure stable operation of the circuit, and a diode 34 is provided to protect the circuit from the back electromotive force of the transformer 46.

Reference numeral 8 denotes a bidirectional thyristor with a control terminal (hereinafter referred to as thyristor), which receives a trigger pulse from the control means 6 from the control terminal and becomes conductive, thereby bypassing the choke coil 2 and causing a current to flow.

With the above configuration, the lamp voltage and lamp current are detected by the lamp voltage detection means and the lamp current detection means 19, and the calculation means 24 applies a predetermined coefficient to each output of the detection means and 19. After multiplication and addition, the difference is amplified and output by comparing it with a constant voltage, and the control means 6 can control the phase of the trigger pulse to the thyristor 8 according to the output of the calculation means 24. Specifically, if the result of multiplying the lamp voltage and lamp current by a predetermined coefficient and adding them together is lower than a certain value, the capacitor 42 is connected to the lamp via the resistor 3Q and the transistor 43.
is charged to increase the voltage of the capacitor 42. Therefore, the capacitor 43 is charged quickly via the resistor 37 and reaches a predetermined value, so that the UJT 46 becomes conductive and a trigger pulse is generated at an early phase, making the thyristor 8 conductive and the current flowing through the choke coil 2. Bypasses the lamp current and increases the lamp current.As a result, the lamp voltage and lamp current are multiplied by a predetermined coefficient and added, and the result approaches a constant value and eventually becomes equal.The lamp voltage and lamp current If the result of multiplying each by a predetermined coefficient and adding them is higher than a certain value, the lamp current is conversely decreased and the addition result becomes a constant value.In this way, the addition result becomes a constant value. , it is possible to reduce variations in color temperature between individual lamps.

Note that the coefficient for reducing variations in color temperature needs to be determined for each type of wrap, since the extent to which lamp voltage and lamp current affect color temperature differs depending on the type of lamp. Tables 1 and 2 show the specifications and shape of the arc tube of a specially manufactured lamp for high color rendering type high pressure sodium lamps (soW and 160W) so that the color temperature will vary when lit using a choke coil type ballast. and shown in FIGS. 2a and 3a. Also, using these lamps, change the power supply voltage to determine the color temperature and lamp voltage V. a. Lamp electrician. The results of the determination are shown in Figures 2 and 3. From now on, the conditions for each lamp to exhibit a constant color temperature around its rated value will be determined. ,
= aV8a+C, and from this it can be seen that after multiplying each of the lamp voltage and lamp current by a predetermined coefficient, the results of their addition can be made constant. By the way, the color temperature in Figure 2 is 2500K.
The straight line is I8a knee 0.0718V8a+ 4.79
In Fig. 3, the straight line to the color temperature 2600 is I. a
=-0,0781V8a+9.36.

Table 1, Table 2, 1! FIG. 4 is a basic circuit configuration diagram showing another embodiment of the lighting device for a high-pressure nut/ram rung according to the present invention. In Fig. 4, 1 is an AC power supply, 4 is a high-voltage thorium lamp,
47 is a DC power supply, and diodes 48, 49, 50
．． 51 and a capacitor 52, it rectifies the output of the AC power supply 1 and outputs DC. 63 is a constant voltage source,
It is composed of a resistor 64 and a constant voltage diode, and the DC power supply 4
Input the output of 7 and output a constant voltage. Reference numeral 66 denotes a step-down chopper power circuit, which is composed of a transformer 57, a diode 68, a capacitor 69, a resistor 60, and a transistor 61. When the transistor 61 is turned off, the electromagnetic energy stored in the transformer 67 is passed through the diode 68 to the high-pressure sodium lamp 4, and the lamp is lit with direct current. The capacitor 59 smoothes the lamp voltage, and the resistor 6o connects the transformer 6.
70 limits the base current from the secondary winding 57a to the transistor 61. Reference numeral 62 denotes lamp voltage detection means, which is composed of a tertiary winding syb of a transformer 67, a diode 63, and a capacitor 64, and stores a voltage proportional to the lamp voltage in the capacitor 64 and outputs it. A resistor 66 is a lamp current detecting means, and generates a current proportional to the lamp current at both ends thereof. 66 is an arithmetic means, which is composed of resistors 67, 68, 69, 70, 71, 72 and transistors 73, 74, 76.

Of these, transistors 73, 74.75 and resistor 69.7
0 constitutes a differential amplifier circuit. By dividing the output of the lamp voltage detecting means 62 by resistors 67 and 68, connecting the resistor 68 and the resistor 66 of the lamp current detecting means in series, and inputting the voltage of this series circuit to the base of the transistor 74, the lamp voltage can be determined. The output of the detection means 62 and the output of the lamp current detection means 66 are each multiplied by a predetermined coefficient and then added, and then all the outputs of the constant voltage source 63 are inputted, and the output is applied to the resistor 71.
．． 72 and input it to the base of transistor 730,
The result of addition is compared with the above, and if the result of addition exceeds a certain value, the transistor 75 is turned on and a signal is output.

Reference numeral 76 denotes a control means, which is composed of a resistor 77 and a transistor 8, which inputs the output signal of the arithmetic means 66 and causes a current to flow through the transistor 78 through the resistor 7a, turning on the transistor 78. , the base and emitter of the transistor 61 are short-circuited to turn off the transistor 61.

With the above structure, the lamp voltage and lamp current are detected by the lamp voltage detection means 62 and the boost current detection means 65, and the calculation means 66 detects the lamp voltage and the lamp current by the detection means 65.
2. After multiplying the respective outputs of 66 by a predetermined coefficient and adding them, compare them with a constant voltage, and when the addition result exceeds a constant value, the transistor 61 is turned off via the control means 76, and the lamp current is increased. You can prevent it from increasing.

In this way, the transistor 61'! so that the addition result becomes a constant value. Since the light is turned on and off, variations in color temperature between individual lamps can be reduced.

Although FIGS. 1 and 4 show an example of a lighting device for AC lighting and DC lighting, respectively, the outputs of the lamp voltage detection means and the lamp current detection means are multiplied by a predetermined coefficient. It should be noted that any other lighting circuit may be used as long as it is configured to control the addition result to a constant value after addition, or even a lighting circuit for high frequency lighting.
not.

Effects of the Invention As described above, according to the present invention, with an extremely simple configuration, it is possible to light the lamps with variations in color temperature between individual lamps kept within a small range, and this invention is extremely useful in practice. .

[Brief explanation of drawings]

FIG. 1 is a basic circuit configuration diagram showing an embodiment of a lighting device for a high-pressure sodium lamp according to the present invention, and FIG. 2a is a diagram showing a basic circuit configuration. b is a diagram showing the shape and characteristic example of a high-pressure sodium lamp, FIGS. 3a and 3b are diagrams showing the shape and characteristic example of other high-pressure sodium lamps, and FIG. 4 is a basic circuit showing another embodiment of the present invention. FIG. 5 is a basic configuration diagram of a conventional lighting device for a high-pressure sodium lamp. 1... AC shin source, 7.62 wrap voltage detection means,
19.66 ・Lamp current detection means, 24°66-
Arithmetic means, 6.76 ・Control means. Name of agent Patent attorney Toshio Nakao and one other person Lamp voltage V (V) Figure 3 Voltage Via CV) Figure 5

Claims (1)

[Claims] a lamp voltage detection means, a lamp current detection means, and an arithmetic means for multiplying the output of the lamp voltage detection means and the output of the lamp current detection means by a predetermined coefficient so as to keep the color temperature of the lamp constant and then adding them. A lighting device for a high-pressure sodium lamp, comprising a control means for controlling the addition result to be constant.