JPS61147497A - High pressure 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 [Field of Industrial Application] The present invention relates to a device for lighting a high-pressure discharge lamp such as a high-pressure sodium lamp or a metal halide lamp at high frequency.

[Conventional device]

A high-pressure discharge lamp (hereinafter simply referred to as a lamp).

By using high frequency lighting using an inverter.

Attempts have been made to reduce the weight of lighting devices. 2 examples of this type of device include JP-A-54-11
There is a device disclosed in No. 1627. Figure 4 shows this conventional device. In Figure 2, (1) is a DC power supply, (2)
is an inverter, (3) is a lamp, and inverter (2) is a lamp.
) is composed of transistors (22a), (22b), a capacitor (2) of a resonant circuit, an output transformer (c), etc. Since the output transformer is configured as a leakage transformer, the current of the lamp (3) is:

This impedance is used to set a predetermined current value.

When the DC power supply (1) is turned on, the transistor (22a
).

A pace current is supplied to (22b) through resistors (23a) and (25b), and self-excited oscillation is started as well-known by the action of feedback winding (2), and the output transformer's secondary Generates high frequency voltage in the next winding (to). As a result, the lamp (3) discharges and lights up. Here, the frequency of the output voltage of the inverter (2) is 1 until the lamp (3) starts discharging, but does the frequency f2 change after the lamp (3) is turned on? 0 which is f1<f2.

After the lamp is lit, the resonant frequency of this inverter is.

This is because the frequency is approximately determined by the cage inductance on the secondary side of the output transformer. If sufficient voltage is supplied to the lamp (3) to start discharging, the output transformer (c) will require a large capacity and its shape will become large.

In contrast, this is a device that lights a lamp from a commercial AC power source using a reactor as a current limiting element.

In order to ensure lamp starting, there was a device that applied a high voltage using a thyristor called a triax. JP-A-47-31466 discloses a conventional device of this kind. Figure 5 shows this conventional device.
) is an AC power supply, (6) is a single-winding transformer, (7) is a bidirectional thyristor called a triac, (8) is a choke coil as a stabilizer, +91 is a triac (7), and a trigger (b). aυ is a high impedance element, and (3) is a lamp. In the device configured as described above, a voltage boosted by the autotransformer (6) from the AC power source (5) is applied to the lamp (3) to start discharging. This causes current to flow through the ballast (8), triggering the triac (7) and causing a predetermined current to flow through the lamp (3). After the lamp is turned on, a trigger current flows through the triac (7) every six half cycles of the AC power source (5) to make it conductive.

However, with this device, a commercial frequency current flows through the triac, so a trigger signal is required every half cycle, and the trigger circuit also requires a special device to make the triac conductive. Rarely.

[Problem that the invention seeks to solve]

With conventional equipment, if you want to start the lamp reliably,
The capacity of the inverter's output transformer has increased, making it larger. Furthermore, at commercial frequencies, the weight of the ballast becomes heavy, and even those that use a triac to supply the starting voltage have to trigger it reliably every cycle.

[Means for solving problems]

The device of the present invention includes an inverter 2 connected to a DC power source.
), a secondary winding (c) and a step-up winding are installed in the output transformer (c) of the Provides means for closing.

[Effect of means to solve problems]

When the switch aO is open, a superimposed voltage generated by the boost winding is applied to the lamp, causing the lamp to start discharging. This closes the switch α and causes a steady current to flow through the lamp.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the device according to the invention.

In the figure, (1) is a DC power supply, (2) is an inverter that performs self-oscillation, (3) is a lamp, and (4) is a lamp (3).
This is a trigger circuit as a detection means that detects the discharge of and triggers a triac αυ as a switch, where αυ is an impedance. The inverter (2) is the output transformer (c) that forms the resonant circuit with the resonant circuit capacitor @.
, the feedback winding wound around this output transformer■.

It consists of a secondary winding (c), a boost winding, etc. This is a self-oscillating push-pull transistor inverter with a resonant circuit. The trigger circuit (4) includes a current transformer I for current detection and a rectifier circuit i43. It consists of a capacitor 14.8 mag.

Provides gate trigger current for triac Q[).

Further, triacs are generally used for phase control of commercial AC power supplies, but their characteristic is that they have a long turn-off time. For this reason, when flowing high frequency current, once the trigger fL is applied, it cannot be turned off.

If the conduction continues continuously, the -.5 phenomenon will occur.

In the device configured as described above, when the DC power supply +11 is turned on, the inverter (2) starts operating as is well known, and generates a high frequency voltage in the output transformer (3). ), the voltages generated in the secondary winding (a) and the booster winding are applied together, so the lamp (3) discharges.Then, the trigger circuit (4) Since the triac a11 is sensed and triac 1II) is tri-powered, the triac a11 becomes conductive. Therefore, a predetermined current flows through the triac a (I'f) in the lamp (3) and lights it up.At this time, the current flowing through the impedance aD is
When the lamp (3) is turned on, the output frequency of the inverter (2) increases and decreases as in the conventional device, and in addition,
The output voltage of the step-up winding also changes due to the lighting of the lamp 13).
It decreases because the voltage of the secondary winding @ decreases. Therefore, the electric current 2 flowing through the step-up winding (c) is greatly reduced after the lamp (3) is turned on, and this winding requires only a small capacity wire diameter.

Unlike low-pressure discharge lamps such as fluorescent lamps, this type of lamp has a low vapor pressure in its arc tube and a low lamp voltage immediately after discharge starts. Therefore, the terminal voltage of the secondary winding # (to) of the output transformer (c) configured as a leakage transformer is very low immediately after starting.

Similarly, since the voltage of the boost winding (2) is also low, the current flowing through the choke coil aυ with impedance αD is particularly small. The resonant circuit of this inverter (2) also includes the current flowing through this choke coil. Therefore, immediately after the discharge of the lamp starts, the output frequency of the inverter (2) is lowered. Therefore, the current of the lamp (31) increases compared to the steady state, which has the effect of shortening the time it takes for the lamp to reach stable lighting.

Next, other embodiments will be described.

It is assumed that the output voltage of the DC power supply +1) is a pulsating current obtained by full-wave rectification of the voltage of the commercial AC power supply. This voltage is shown in FIG. 6(a). Then, the voltage generated by the inverter
In the shear lamp (3) as shown in figure (b), the sixth
A current having a rest period T flows as shown in FIG. FIG. 2 shows an example of the trigger circuit of the triac a when there are periodic rest periods in the current flowing through the lamp (3). With reference to the figure, points different from the apparatus shown in FIG. 1 will be explained. When the lamp (3) discharges, a signal voltage is generated in the winding G49 coupled to the choke coil I, and this signal voltage is rectified by a diode and triggers the thyristor.The thyristor has an output transformer. A DC voltage obtained by rectifying and smoothing the output voltage of the auxiliary winding (2) provided in the negative side magnetic circuit of (c) is applied, and continues to supply a trigger signal to the triac aO. Even if the current stops flowing through the lamp (3) or the inverter (2) stops generating the output voltage, the trigger signal is still supplied to the triac (a), so current cannot flow through the lamp (3) again. I can do it.

In this explanation, we have taken as an example the case of a pulsating DC voltage as the DC power supply +11, but it goes without saying that in the case of other DC power supplies, the operation of the inverter (2) is periodically stopped for a short period of time to create a rest period. It can also be applied when Thyristor (
For the trigger in c), an alternator may be used as in the device shown in FIG.

FIG. 3 shows still another embodiment, and FIG. 9 shows another embodiment.

The innovidance r1υ is a capacitor, and after the lamp is turned on, the current x1 flowing through the capacitor aυ is used to reduce the current flowing through the triac sauce, thereby reducing the loss in this switch. In this case, it is more effective if the output transformer (c) is not a cage transformer. In short, if the impedance that limits the lamp current is an inductive reactance, a capacitive reactance may be used as the impedance aυ, and if it is the opposite, the impedance αυ may be an inductive reactance. Here, if the electric current 1 flowing through the impedance aυ is increased.

Although the loss of the triac α value decreases, if it increases too much, the capacity of the output transformer (c) increases due to the increase in the current of the step-up winding. About 50% is preferable.

Although not mentioned above, the inverter (2) is particularly effective if it has a self-oscillating resonant circuit.
It could be something else. The output transformer (c) is.

Although a leakage transformer is used, a normal output transformer may also be used with a different impedance for limiting the lamp current.

Although a current transformer is used as a means for detecting lighting of a lamp, other detecting means such as detecting light may be used. Furthermore, although a triac was used as the switch αG, the behavior circuit r may be modified as appropriate.

It is also possible to use a transistor or the like as a switch. [Effects of the Invention] As described above, the device of the present invention makes it possible to reliably light the lamp without significantly increasing the capacity of the output transformer. 0 has the advantage of being able to

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the invention, FIG. 2 is a circuit diagram showing another embodiment of the invention, FIG. 3 is a circuit diagram showing still another embodiment of the invention, and FIG. 4 is a circuit diagram showing another embodiment of the invention. The figure shows a conventional device (
b) Schematic diagram, Figure 5 is an enclosure diagram showing another conventional device, Figure 6
The figure is a waveform diagram for explaining the operation. Among them, the code +11 is a DC power supply, (2) is an inverter, (
3; is a lamp, C4) is a detection means, +11 is a switch, all is impedance, a! 9 is an output transformer,
@L secondary winding. (to) is the boost winding. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (6)

[Claims] (1) Convert DC voltage to high-frequency voltage, output high-frequency current from an internal output transformer, superimpose the output of the secondary winding and boost winding of this output transformer, and supply it to the high-pressure discharge lamp. An inverter, a switch connected between the secondary winding of the output transformer and the high-pressure discharge lamp, an impedance also connected between the step-up winding of the output transformer and the high-pressure transformer, and an impedance of the discharge lamp. A high-pressure discharge lamp lighting device comprising a detection means for detecting a discharge operation and closing the switch. (2) Claim 1, characterized in that the inverter is a device that performs self-excited oscillation operation and has a resonant circuit.
The high-pressure discharge lamp lighting device described in 2. (3) The high-pressure discharge lamp lighting device according to claim 1 or 2, wherein the output transformer is constituted by a leakage transformer. (4) The impedance connected in series to the boost winding is
A high-pressure discharge lamp lighting device according to any one of claims 1 to 3, characterized in that the high-pressure discharge lamp lighting device comprises a reactance component of the same type as the impedance that limits the discharge current of the discharge lamp. (5) The impedance connected in series to the boost winding is
A high-pressure discharge lamp lighting device according to any one of claims 1 to 3, characterized in that the high-pressure discharge lamp lighting device comprises a reactance component of a different type from an impedance that limits the discharge current of the lamp. (6) A high-pressure discharge lamp lighting device according to any one of claims 1 to 5, wherein the switch is constituted by a triac.