JPS6358793A - Discharge lamp lighter - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a discharge lamp lighting Vl arrangement for lighting a nominally 150 watt metal halide lamp with a rectangular wave alternating current containing high frequency ripple, and in particular to a method for preventing acoustic resonance of the lamp. The present invention relates to a discharge lamp lighting device.

[Prior Art] Since a discharge lamp has a resistance of 0↑1, it requires a device that limits and supplies the lamp current, that is, a discharge lamp lighting device. As this type of device, there are known devices that limit the lamp current by chopping the DC voltage at a high frequency, or devices that convert the DC voltage to a high frequency voltage and then limit the lamp current using an inductor or capacitor.

According to such a device, in addition to being able to significantly reduce heat loss when direct current is limited by a resistor, it is also possible to significantly reduce heat loss when limiting direct current using a resistor. can be made smaller and lighter.

Further, when a discharge lamp is lit with direct current, the gas filled in the lamp 3 may be unevenly distributed or electrolysis may occur, resulting in color unevenness. Therefore, by roughly converting the chopped DC voltage into an alternating voltage and supplying it to the discharge lamp,
Discharge lamp lighting devices that take measures against color unevenness are also known.

[Problems to be Solved by the Invention] Incidentally, the lamp current supplied to the discharge lamp from such a device contains high frequency components such as high frequency ripples and currents. When a current of a certain frequency is supplied, a so-called acoustic resonance phenomenon occurs in which the arc column fluctuates or disappears, resulting in the inconvenience of unstable lighting.

The present invention has been made in view of the above-mentioned problems in the conventional type, and an object of the present invention is to provide a tllffl lamp lighting device for a metal halide lamp that is small in size, made of pumice, and stable in the lighting state.

As a result of thorough inspection and sealing to eliminate the above-mentioned problems, the inventors of the present invention succeeded in reducing the size and lightness of the chain by chopping the lamp current using a high frequency to limit the current, or by converting it to a high frequency and limiting the current using an inductance or capacitor. It has been discovered that even when using a discharge lamp lighting device designed for this purpose, metal halide lamps can be stably lit by limiting the suspension and frequency of high-frequency ripples or high-frequency components contained in the lamp current, and the present invention has been achieved. Reached.

[Means and effects for solving the problems] The present invention provides a discharge lamp lighting device for lighting a metal halide lamp of nominally 150 watts with a rectangular wave alternating current including high frequency ripples, and the frequency and content rate of the high frequency ripples are shown in FIG. It is characterized by being set in the stable region (shaded area) of .

In other words, in the present invention, by chopping the rectangular wave at a higher frequency, it is possible to miniaturize the circuit elements for limiting the lamp current, thereby making the device more compact and compact, and as a result, the high frequency ripple contained in the rectangular wave is reduced. component to a given m
The lamp is lit stably with the following limitations.

Here, the ripple content rate is defined as the peak current value a of the alternating current in FIG.
)/a means.

In the present invention, the frequency of the rectangular wave is not particularly limited, but is preferably a low frequency, such as a commercial frequency or
It is 12.

Furthermore, in the present invention, one frequency refers to a frequency higher than the audible frequency range. The preferred range is 20kHz to 80kHz.
It is kHz. The frequency of high frequency ripple is 20kllZ
If it is less than this, it is not preferable because it will cause audible noise and increase the size of the circuit components.

On the other hand, if it exceeds 80 kHz, switching loss increases and the thermal efficiency of the device deteriorates, which is not preferable. Also,
If the frequency of the high frequency ripple is less than three times that of the rectangular wave,
The shape of the above-mentioned rectangular wave is distorted by a filter, etc. for keeping the high-frequency ripple within the range shown in Fig. 1 above, and it becomes difficult to apply the definitions of the size and ripple content of the rectangular wave according to the present invention. The frequency of the high frequency ripple is preferably more than three times the frequency of the rectangular wave.

In the present invention, the lower limit of the high frequency ripple content is not particularly limited, but in order to significantly reduce the high frequency ripple content, a large filter circuit is required, and the circuit efficiency deteriorates, which is impractical. Therefore, the ripple content is
It is preferably about 1/2 or more of the upper limit of the above range.

Examples] The present invention will be described in detail below using the drawings.

FIG. 3 shows a circuit configuration of a discharge lamp lighting device according to an embodiment of the present invention. The device shown in the figure includes a DC power supply 1 consisting of an AC power supply 11, a high-frequency rectifier circuit 12, and a smoothing capacitor 13, a step-down chopper circuit 2 consisting of a transistor 21, an inductor 22, a diode 23, etc., and transistors 31 to 31. Bridge inverter 3 consisting of 34 etc. and metal halide lamp (I]Q of nominal 150 watts
It is equipped with a load 4 consisting of I-150W/ND L ).

Next, the operation of the apparatus shown in FIG. 3 will be explained.

When the DC power supply 1 is turned on, a base drive circuit (not shown) of the chopper circuit 2 generates a high frequency rectangular wave with a duty ratio corresponding to the ramp 'f:i current, and applies it to the transistor 21. As a result, the transistor 21 is turned on and off at a high frequency, and a DC output containing high frequency ripple is supplied from the chopper circuit 2 to the inverter 3. bridge inverter 4
Now, the transistor 31 is controlled by the υ control circuit (not shown).
．． 34, 32, and 33 are driven alternately. In other words, while the transistors 31 and 34 are on, the DC output including high frequency ripple from the chopper circuit 2 flows through the path of the transistor 31, the lamp 4, and the transistor 34.
On the other hand, while the transistors 32 and 33 are on, the DC output including high frequency ripples from the chopper circuit 2 flows through the path of the transistor 33, the lamp 4, and the transistor 32. That is, the lamp 4 includes a transistor 31
．． Current and voltage are supplied with a waveform in which a high-frequency ripple determined by the on-off period of the transistor 21 is superimposed on an alternating rectangular wave determined by the on-off period of transistors 34, 32, and 33.

In the device shown in FIG. 3, in order to reduce the content of high-frequency ripples contained in the current and voltage supplied to the lamp 4, the inductance of the inductor 22 is increased.
There are methods such as lowering the on-duty of the transistor, connecting a band eliminator or a low-pass filter between the chopper circuit 2 and the inverter, or in series with the lamp 4.

FIG. 4 shows a circuit configuration of a 1J51 electric lamp lighting device according to another embodiment of the present invention.

The device shown in the figure is a device called a pair regulator, which turns transistors 52 and 54 on and off alternately at low frequency, turns on and off transistor 53 at high frequency while transistor 52 is on, and turns transistor 54 on and off at high frequency.
The transistor 51 is turned on and off at a high frequency while the transistor 51 is on. As a result, the lamp 4 is supplied with a low frequency rectangular wave current and voltage including high frequency ripples. In this case, the frequency of the high frequency ripple is determined by the on/off period of the transistor 51.53, and the frequency of the rectangular wave is determined by the on/off period of the transistor 52.54. Further, the high frequency ripple content rate is determined by the ratio of the input DC voltage to the lamp voltage, the on/off period of the transistor 51, 53, the on/off duty, the inductance of the inductor 55, 56, etc.

The present inventors determined the relationship between the frequency and amount of high-frequency ripple in the lamp current supplied to the lamp 4 and whether or not the lamp 4 is lit stably using a nominally 150 watt metal halide lamp (1-IQ l -150W/NDL). ) to 400Hz
Measurements were made by stippling with a rectangular wave, and the characteristic diagram shown in FIG. 1 was obtained. In the figure, the shaded area is the range in which all five samples randomly selected from different lots were lit stably.

According to the findings of the present inventors, acoustic resonance is caused by a sudden change in the period e (ripple) of the power supplied to the lamp, and there is no particular t/l limit on the frequency of the rectangular wave. The problem is the frequency and content of high-frequency ripples that break the rim-shaped waveform that is the ideal state for power supply.

[Effects of the Invention] As described above, according to the present invention, a metal halide lamp of nominally 150 watts is basically lit with a square wave, and the rectangular wave lamp current and voltage are chopped at a high frequency and current limited by an inductor or capacitor. In a discharge lamp lighting device that aims to reduce the size and weight of the device, the above-mentioned high-frequency chopping limits the frequency and frequency of the high-frequency ripple included in the basic rectangular wave to a predetermined value. It was possible to turn on the light stably without causing any acoustic resonance phenomenon.

[Brief explanation of drawings]

Fig. 1 is a point versus characteristic diagram of HQ l-150W/NDL, which is a nominally 150 watt metal halide lamp, Fig. 2 is an explanatory diagram of the lamp current waveform of the present invention, and Fig. 3 is a diagram of the lamp current waveform according to the embodiment of the present invention. FIG. 4 is a circuit diagram of a discharge lamp lighting device according to another embodiment of the present invention. 1... DC 'ifi source 2... Bukoppa circuit 3... Bridge inverter 4... Lamp 5... Pair regulator

Claims (1)

[Claims] 1. Rectangular wave alternating current including high frequency ripple, nominally 150
In a discharge lamp lighting device for lighting a watt metal halide lamp, the content rate of the high frequency ripple is 30% or less when f is the frequency of the high frequency ripple and 20kHz≦f<40kHz, 40kHz.
20% or less when z≦f<70kHz 70kHz≦f≦
A discharge lamp lighting device characterized in that the operating frequency is 30% or less at 80kHz. 2. Claim 1, which includes a step-down chopper that includes a switching element that turns on and off at a high frequency and generates a direct current including the high-frequency ripple, and a bridge inverter that converts the output of the step-down chopper into rectangular alternating current.
Discharge lamp lighting device as described in . 3. The first and second connected in series to the DC power supply, respectively.
the switching element and the third and fourth switching elements, the connection point of the first and second switching elements and the third
and a discharge lamp connected via an inductor to the connection point of the fourth switching element, a low frequency drive circuit that alternately turns on and off the first and third switching elements at low frequency, and a low frequency drive circuit that alternately turns on and off the first and third switching elements. A high frequency drive circuit is provided that drives the fourth switching element at high frequency during the period when the switching element is on, and the second switching element at high frequency during the period when the third switching element is on, and generates high frequency ripples in the discharge lamp. 2. A discharge lamp lighting device according to claim 1, which supplies a low frequency rectangular wave alternating current.