JPS61271791A - Discharge lamp lighting apparatus - 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 [Technical Field 1] The present invention relates to a discharge lamp lighting device for lighting a high-pressure discharge lamp.

[Background Art] A general discharge lamp lighting device is composed of an ovary-coil, a transformer, a capacitor, etc., either singly or in combination.
Both size and weight are large, so in the case of fluorescent lamps, the practical use of high-frequency lighting devices using switching transistors has made it possible to reduce the size and weight of the lighting device.

By the way, it has been known that arc instability (fluctuation, extinction, arc tube destruction, etc.) due to so-called acoustic resonance occurs during high-frequency lighting of high-pressure discharge lamps (for example, Journal or Applied Phys.
ics 49(5) May 1978 p2680-
p. 2683), various methods have been proposed to prevent this, such as rectangular wave lighting and frequency limitation (for example,
I, E, S TRN5^C00N Dec, 196
9 Initial Characteristics
cs of If Intensity
Discharge Lamps on Hi
gh Frequency Power”).

Among the preventive measures that have been proposed, for example,
32880, etc., there is a method of ``automatically sweeping the chip speed of high frequencies to alleviate the problem of acoustic resonance'', that is, the concept of frequency modulation.

The formation mechanism of the unstable arc that occurs when a high-pressure discharge lamp is operated at a high frequency is considered to be as follows. In other words, ■ High-frequency fluctuations in electrical input ↓ ■ Pressure changes in the gas inside the arc tube ↓ ■ Standing pressure waves are generated at a special frequency ↓ ■ Pressure amplitude exceeding the limit causes 7-way instability. The "special frequency" is the so-called acoustic resonance frequency, which is determined by the 7-dimensional dimension (actually, the shape of the arc tube) and the sound speed inside the arc tube, and the sound speed is the same as the average molecular weight of the gas. Since it is determined once the ion temperature is determined, it is relatively easy to obtain these values if you know them. Furthermore, the question of at what acoustic resonance frequency ``arc instability due to pressure amplitude exceeding the limit'' occurs is a problem in the nonlinear domain, and the answer cannot be found simply.

However, in the case of frequency modulation that automatically sweeps high frequencies, which has been proposed as a means to avoid arc instability due to acoustic resonance, there are the following problems to be solved.

In other words, the point shown in Japanese Patent Publication No. 57-32880 is that after full-wave rectification of an AC power supply, in a device that lights a discharge lamp using a high-frequency lighting device, the above-mentioned full-wave rectified voltage waveform is used to improve the restriking characteristics. This is a method for smoothing only the valleys of the arc, and only the idea of automatically sweeping the frequency is mentioned in order to eliminate the instability of the arc caused by acoustic resonance. For example, in 1983, it was found that the condition of automatically sweeping the frequency as stated in Japanese Patent Publication No. 57-32880 was insufficient to eliminate instability.
You don't even need to look at No. 43 of the Annual Conference of the Illuminating Society of Japan (it is well known).

On the other hand, Japanese Patent Laid-Open No. 56-48095 emphasizes that the modulation frequency includes a frequency that allows stable lighting.

However, in a high-pressure discharge lamp, the state of the arc changes from moment to moment during the process from startup to steady lighting, and the so-called acoustic resonance frequency also changes from moment to moment.
It is reasonable to assume that the Patent Publication No. 56-48095 does not consider compensation for such an output state.

That is, even if the frequency modulation is set so that stable lighting can be achieved during steady lighting, it cannot cover the range of output control such as main tube voltage control.

Figure 6 shows a basic high-frequency discharge lamp lighting device made in view of the above points, in which the AC power source v1 is full-wave rectified by a full-wave rectifier DB, and a capacitor is applied to the full-wave pulsating waveform. A self-excited inverter A generates a DC voltage in which the discharge voltage waveforms of C1 and C2 are superimposed.

I am inputting it to Inverter A is transistor Q,
, Q2, starting resistors R,,R, and oscillation transformer OT
The transistors Q, Q2 are connected in series in opposite directions, and are connected between the primary winding N1 of the oscillation transformer OT, and their bases are fed back to each other. They are connected to each other through the winding IN and to the positive output side of the full-wave rectifier DB through the corresponding starting resistor RI-R2. Also, oscillation transformer OT
A high pressure discharge lamp DL is connected to the secondary winding N2. FIG. 7(a) shows the input voltage waveform to the inverter A, and the broken line shows the full-wave rectified voltage waveform obtained by full-wave rectifying the AC type 1V with the full-wave rectifier DB. C+
, C2 are superimposed, and the inverter A
, so it has the waveform shown.

Here, capacitors C, , C2 and diodes D1 to D,
The operation will be explained. First, inverter A.

Discharging to the capacitor consists of a parallel discharge system of capacitor C8, diode D, capacitor C2, and diode D2, and charging to capacitor CI-C2 is performed by series charging of capacitor C1, diode D3, and capacitor C2 from a full-wave rectifier DB. It is done in a system. Therefore, the voltage of capacitor C1 and capacitor C2 is approximately 1/1/2 of the peak value of AC power supply ■.
It becomes 2. Figure 7(b) shows the direct current 11 of the full-wave rectifier DB.
1 indicates current, and during period T when the voltage of capacitor C1 or C2 is higher than the full-wave rectified voltage of AC power source ■1, no current flows than the AC power source ■1 voltage, and the voltage of capacitor C1 or C2 is higher than the full-wave rectified voltage of AC power source ■1. When the full-wave rectified voltage of AC fi source ■ becomes lower (T, period), current starts to flow from AC power source V1 to inverter A1, and the series voltage of capacitor CI and capacitor C2 becomes lower than AC power source ■1. At time t1, AC current 1V, current to inverter A1 and capacitor C1
The charging current (shaded area) to the series circuit of capacitor C2 and capacitor C2 are superimposed. W47 diagram (e) is a high pressure discharge lamp DL
This is a simulated representation of the current waveform, and the broken line is the envelope of the current. Note that the operation of the inverter A1 is well known, so a description thereof will be omitted.

In the circuit of FIG. 6, focusing on the lighting frequency of the high-pressure discharge lamp DL by the inverter A, the oscillation period is determined by the inductance component of the capacitor C3 and the oscillation transformer OT, and the resistance component of the high-pressure discharge lamp DL, and the oscillation period is In other words, it corresponds to the lighting frequency. Now, if the high-pressure discharge lamp DL is a fixed resistance, the above-mentioned vibration period is uniquely determined, so the frequency is also constant, but the equivalent resistance of the discharge lamp is as shown in Figure 7 (c).
Where the value of the envelope is large, it is relatively small, and in the opposite case, it changes relatively large.

Therefore, the lighting frequency of the high-pressure discharge lamp DL is high at the peaks in FIG. 7(a) and low at the valleys. In other words, when a discharge lamp is lit with a self-excited inverter such as inverter A in Figure 6, frequency modulation will automatically be applied if the input current of inverter A1 has an amplitude. .

On the other hand, assuming a high color rendering type high pressure sodium lamp as the high pressure discharge lamp DL, it is necessary to have a color temperature with little variation due to the characteristics of the discharge lamp. It has been found that it is sufficient to keep the tube voltage constant even when lamp variations occur. In such a case, if the high pressure discharge lamp DL was simply turned on using the circuit shown in FIG. 6, the color temperature would vary greatly.

FIG. 8 shows an example of a configuration for eliminating variations in color temperature, and explanations of circuit components having the same symbols as those in FIG. 6 will be omitted. The tube voltage detection unit A2 connected to both ends of the high pressure discharge lamp DL is a detection transformer Tf.

, a full-wave rectifier DB, a resistor Rl 2, and a capacitor C. A phase control triac Q inserted between the AC power supply v1 and the full-wave rectifier DB.
, are controlled by the control unit A, and the control unit AiJ! )? xTr, full wave rectification 1DBt, resistance R.

~R11% diode D, ~Ds, pulse transformer PT
, capacitors C1, C., general-purpose timer IC, and operational amplifier IC2. This control section A.

The general-purpose timer IC1 inputs a voltage divided by resistors R, , R, to the terminal (2), and is synchronized with the AC power source (2) by a waveform similar to the full-wave rectified waveform of the AC power source (2). The operation of the control unit A3 AC power supply ■1 for each half cycle is basically performed by the DC voltage at the ■terminal of the general-purpose timer IC, the resistor R6, the capacitor C, and the capacitor C1.
Comparing the charging voltage waveforms created at both ends of , the ■terminal of general-purpose timer IC1 becomes L'' at the intersection of the two, thereby discharging the charging voltage of capacitor C6 on the primary side of pulse transformer PT, and inverting the triac Q. , and when the brass voltage increases, the operational amplifier IC,
The voltage proportional to the tube voltage is the general-purpose timer IC.
Since it is added to the terminal, the triac Q,
With a delay, the tube voltage is suppressed, and in the opposite case, it works in the exact opposite way to suppress the drop in tube voltage. The above states are shown in Figures 9 and 10. Figure 9 shows the case where the tube voltage is low, and Figure 10 shows the case where the W voltage is high, and (a) in each figure shows the case where the tube voltage is low. In addition, (b) in each figure shows the envelope of the high-frequency current of the high-pressure discharge lamp DL, and the broken line in each figure (a) is the AC power supply ■1.
The full-wave rectified voltage waveform is shown.

By the way, when the tube voltage is suppressed as described above, it is generally the case that the inverter A1! In the configuration, as mentioned above, the alpha lamp frequency is controlled by the input voltage to the inverter 'A1, so if it contains a frequency component that avoids acoustic resonance in the state shown in Figure 9, for example. Also the first
In the state shown in Figure 0, there is a period in which the instantaneous value of the input voltage to inverter A does not include the instantaneous value in the case of Figure 9, and the frequency determined by the voltage during this period is the frequency that avoids acoustic resonance. Therefore, even if the arc is stable in the state shown in FIG. 9, the arc becomes unstable in the state shown in FIG. 10, which is a disadvantage.

In addition, in order to ensure that a frequency that avoids acoustic resonance is included in both the states shown in FIGS. 9 and 10, the frequency should be set so that the frequency is in a relatively low range of the input voltage to the inverter A1. In this case, the power supplied to the high-pressure discharge lamp DL during the frequency period at which acoustic resonance is avoided is relatively small, so there is a problem that the effect of avoiding acoustic resonance is small.

[Objective of the Invention 1 The present invention has been made in view of the above-mentioned problems, and its object is to provide a high-pressure discharge lamp using a self-help inverter! ! In order to avoid acoustic resonance, the lighting frequency that avoids acoustic resonance is set so that it is near the peak of the AC power source, and the output is controlled in a predetermined section that does not include the vicinity of the peak, thereby controlling the main tube voltage to avoid acoustic resonance. It is an object of the present invention to provide an electric lamp lighting device which can reduce the color temperature variation range when a high color rendering type high pressure sodium lamp is used as a load.

[Disclosure of the Invention] K (Takumi 1) Figure 1 shows Embodiment 1 of the present invention, and the circuit configurations with the same symbols as the circuit in Figure 9 are the same, and their explanation will be omitted.Thyristor Q4 is a diode D connected in parallel with the thyristor Q in the opposite direction for charging the capacitor C3.
, l is for discharging the capacitor C1. control part A,
may have the same configuration as the control unit A3 in Fig. 9, and the high pressure discharge lamp D
When the tube voltage of L is about to become high, it delays the conduction time of thyristor Q, and when the tube voltage is about to become low, it works to advance the conduction time of thyristor Q.

Figure 12 shows the input voltage waveform to inverter A1 to explain the main points in Figure 1, and (a) shows the high-pressure discharge lamp DL with low tube voltage.
When lit, (b) is a high pressure discharge lamp DL with high tube voltage.
The figure shows the case where the AC type [IV] is turned on, and there is a difference in the trough u'IL pressure of the full-wave rectified waveform of the AC type [IV].

In Fig. 2, if (A) and (C2) are the upper and lower control limits of the tube voltage, respectively, all control states can be adjusted by setting the frequency to include the frequency at which acoustic resonance can be avoided at least within the period T31. Since it includes a frequency at which acoustic resonance can be avoided, arc instability due to acoustic resonance can be avoided even when output is controlled, and the full-wave rectified waveform of AC type iaj V+ can be avoided. By setting a frequency that avoids acoustic resonance near the peak value, the proportion of that frequency in the output power increases, increasing the certainty that arc instability due to acoustic resonance can be avoided. be. Note that periods T31 and T41 indicate periods in which the voltage of the capacitor C3 is lower than the full-wave rectified voltage of the AC power source v1, and periods T32 and T42 indicate periods in which the voltage is higher than the full-wave rectified voltage of the AC power source v1.

Figure 3 shows the circuit of Example 2, and Figure 4 shows the input voltage waveform to the inverter A1 in Figure 3. While it is controlled according to the voltage, in the circuit shown in Figure 3, capacitor C3 is an AC power source ■.

It is charged through the diode D3° to the peak value of the full-wave rectified waveform of As shown in Figure 4 (b), the discharge is slow. still,
In FIG. 3, circuit components that are the same as those in FIGS. 1 and 9 are given the same symbols and their explanations are omitted. Furthermore, the periods T31tT321T, . . . , 7.2 in FIG. 4 have the same meaning as in FIG. tji2. Therefore, in the circuit of FIG. 3 as well, the first The same effect as in the case shown in the figure can be achieved. Furthermore, the period Tl121T4ffi
Among them, there is a voltage value near the peak value of the full-wave rectified waveform of the AC power source (1), so that the effect of avoiding the instability caused by acoustic resonance becomes even greater.

K191 pI45 shows a circuit of the third embodiment, in which a circuit other than the one shown in FIGS. 1 and 3 is used as the inverter A. The circuit in Figure 5 is a so-called series inverter circuit, which includes a high-pressure discharge lamp DL, a switching transistor Q l' I Q +1° that opens and closes alternately, a capacitor C,,C, and transistors Q,,Q on the same core. , drive volume IIAN4. Ns and the transistor Q l'
Chitaak coil L2 that operates l Q 2゛ with self-pity
, resistor R13, capacitor C1゜, voltage response switch Q
6, consisting of a diode D, resistors R13 to RI5, a capacitor C1°, a voltage responsive switch Q, and a diode D.
, forms a starting circuit for the inverter A1.

In the case of this embodiment circuit as well, the lighting frequency is the same as inverter A in the circuit shown in FIG.
Since it is determined by the equivalent resistance of L, the vibration period by capacitor C, or C1, when a variable resistance element such as a high-pressure discharge lamp DL is used as a load, the lighting frequency changes depending on the input voltage value to inverter A1. It is.

As mentioned above, the inverter A1 may be any inverter as long as it has a vibration system including the high pressure discharge lamp DL. Furthermore, although the above description has mainly focused on increasing the tube voltage of the high-pressure discharge lamp DL, it is clear that the present invention can also be applied to output control such as constant power generation. Furthermore, the above example takes a high color rendering type high pressure sodium lamp as an example, and if the characteristics of the discharge lamp are statically positive (if the tube voltage increases, A, then by lowering the input voltage to A and reducing the tube current, the tube voltage can be reduced). However, it is also clear that for loads that statically exhibit negative characteristics, such as mercury lamps, it is sufficient to control the input voltage to inverter A in the completely opposite way. .

[Effects of the Invention] The present invention comprises a pulsating current power source obtained by full-wave rectification of an AC power source, an automatic inverter that operates using the pulsating current power source as a power source, and a high-pressure discharge lamp that is lit by the output of the inverter. In a discharge lamp or alpha lamp device, an LC resonance type inverter is included in the high-pressure discharge lamp and the lighting frequency is determined, and the input voltage of the inverter is made variable over a predetermined period not including the peak value of the pulsating current power source. and a means for adjusting the output in the variable voltage portion of the variable period, and the frequency that can avoid acoustic resonance in the high-pressure discharge lamp is set near the peak value of the pulsating current power source, so that the main tube voltage control can be adjusted acoustically. This can be achieved while avoiding spatial resonance, and even if a high-color rendering type high-pressure sodium lamp is used as the high-pressure discharge lamp, it has the effect of reducing the width of color temperature variation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of Embodiment 1 of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the same as above, and FIG. 3 is a circuit diagram of Embodiment 2 of the present invention.
FIG. 4 is a waveform diagram for explaining the operation of the same as above, FIG. 5 is a circuit diagram of Embodiment 3 of the present invention, FIG. 6 is a circuit diagram of the second example, FIG. 7 is a waveform diagram for explaining the operation of the same as above, FIG. 8 is a circuit diagram of another conventional example, and FIGS. 9 and 10 are waveform diagrams for explaining the operation of the same.
DL is a high pressure discharge lamp, A1 is an inverter, A2 is a tube voltage detection section, and A is a control section. Figure 3 *41i5 ^ ^
＾0 ri Q
-1 ζ--1o
D-1--

Claims (1)

[Claims] (1) A discharge lamp lighting device consisting of a pulsating current power source obtained by full-wave rectification of an AC power source, a self-excited inverter that operates using the pulsating current power source as a power source, and a high-pressure discharge lamp that is lit by the output of the inverter. , an LC resonance type inverter including a high pressure discharge lamp and whose lighting frequency is determined, and an input voltage of the inverter variable over a predetermined period not including the peak value of the pulsating current power supply, and a variable voltage during the variable period. 1. A discharge lamp lighting device, comprising means for partially adjusting output, and a frequency that can avoid acoustic resonance in the high-pressure discharge lamp is set near a peak value of the pulsating current power source.