JPH01120796A - Starting device of electric discharge lamp - Google Patents

Abstract

PURPOSE:To enable control of an electric discharge lamp and smooth start thereof by repeatedly stopping switching elements of an inverter for a prescribed term. CONSTITUTION:An inverter 2, which lights an electric discharge lamp 1 by supplying a high-frequency current about in the shape of a sine wave, consists of switching elements Q1, Q2 connected to a DC power supply 3 and a control circuit 4, which controls those elements to generate high frequency voltage, while forming a resonance circuit 8 consisting of a coil 7 and a capacitor 6. At the time of starting the electric discharge lamp 1, the switching elements Q1 and Q2 of the inverter 2 are repeatedly stopped for a period of about integer times of a half period of the output frequency of the inverter 2. Thereby, the discharge lamp 1 can be smoothly started as well as the electric discharge lamp can be controlled without changing the output frequency of the inverter.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention comprises an inverter and a resonant circuit, and a
``Radiator 7 [related to a lamp lighting device] that supplies high-frequency current to a lamp.

[Prior Art] Lighting discharge lamps such as fluorescent lamps at high frequencies using inverters has already been practiced. As a method for controlling the high-frequency power, there is a document described in the 1985 Illuminating Engineering Society Conference Proceedings, page 35, or Japanese Patent Application Laid-Open No. 1983-1989.
As disclosed in Japanese Patent No. 271792, etc., there is a known device that controls the output power to the discharge lamp by changing the frequency of the output voltage of an inverter.

A device for controlling the single section (dimming) of a discharge lamp by changing the output frequency of this inverter will be explained based on the collection of lectures of the Illuminating Engineering Society of Japan. Figure 6 shows the conventional device,
In the figure, l is a discharge lamp serving as a load of an inverter 2, and a high frequency current is supplied to this discharge lamp 1 via an inductor L.

Then, when the operating frequency of the switching elements QI+Q2 of the inverter 2 is increased, the current of the discharge lamp 1 decreases due to the action of the inductor L, and dimming is performed.

The operation described in L is shown for the case where the discharge lamp 1 serving as the load is a metal halide lamp, but the dimming can also be performed using a similar principle in a discharge lamp such as a fluorescent lamp.

In addition, in discharge lamps such as fluorescent lamps, -
It is desirable to preheat the electrodes, and for this reason, an inverter for preheating the electrodes is installed separately from the inverter for lighting the discharge lamp, or as shown in Japanese Patent Publication No. 59-956, The peak voltage applied to low -F
It is being done.

[Problem that the invention seeks to solve]

Conventional discharge lamp lighting devices control the discharge lamp by changing the frequency of the output voltage of the inverter as described above, so an inverter that uses a highly efficient resonant circuit is used. It is difficult to do so, and there are problems in that changes in the output frequency cause large losses in the switching elements of the inverter, and that the discharge lamp cannot be started smoothly unless other means are used.

This invention was made to solve these problems, and it is possible to emit radiation without changing the output frequency of the inverter. ``The purpose of this invention is to provide a discharge lamp lighting device that can control the lamp and start the discharge lamp smoothly.

[Step-f to solve the problem]

A discharge lamp lighting device of the present invention includes an inverter and a resonant circuit that control a switching element connected to a DC power source to generate a high frequency voltage, and supplies a substantially sinusoidal high frequency current to a discharge lamp. When starting the I
A period approximately an integer multiple of a half cycle of the high frequency voltage wave number indicated by iq,
The switching element is repeatedly stopped.

[Effect]

In the discharge lamp lighting device of the present invention, at the time of starting the discharge lamp, a period of approximately an integral multiple of a half cycle of the output frequency of the inverter;
Since the switching elements of the inverter are repeatedly stopped, the discharge lamp can be controlled without changing the output frequency of the inverter, and the discharge lamp can be started smoothly.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In the figure, 1 is a discharge lamp such as a fluorescent lamp, and 2 is an inverter that supplies a substantially sinusoidal high-frequency current to the discharge lamp 1 to light it. , this inverter 2 includes switching elements Q1, Q2 and these switching elements Ql connected to a DC power supply 3.

It is composed of a control circuit 4 that controls Q2 and generates a high frequency voltage. 5.6 is a capacitor, 7 is a coil,
This coil 7 and capacitor 6 form a resonant circuit 8.

FIG. 2 is a specific circuit diagram of the fld control circuit 4. As shown in FIG. In the figure, 11 is an excavation circuit (O3C), 12 is a flip-flop (F/F), and the output frequency of this flip-flop 12 drives switching elements Ql and Q2.

13.13 is an AND circuit; 14.14 is each of the above switching elements Q1. Q 2 is a drive circuit that provides a drive signal; 15 is a frequency divider circuit that generates a signal that is the output of the oscillation circuit 11 etc. (↓) divided into, for example, 1/2.1/4; Switching element Q1 . It is provided to retract and stop Q2. Reference numeral 16 is a changeover switch for selecting full light or dimming, and reference numerals 17 and 18 are timers A and B, respectively, and their contacts are connected to a frequency dividing circuit 15 and an AND circuit 13 as shown.

Next, the operation will be explained using the signal waveform diagram shown in FIG. In the lighting device with the above configuration, when the power is turned on, the switching elements Q, Q2 of the inverter 2 switch to (d) or (f) in FIG. 3 regardless of the selection state of the changeover switch 16.
A dimming (preheating) state is entered by the dimming signal of the frequency dividing circuit 15 shown in (h) and the like. Next, when the timer A17 times up, the dimming signal frequency-divided by L is not applied, and (
As shown in (a), (b), and (c), it becomes a full-light state. Further, when the timer 818 times up, the frequency-divided signal is applied again and the light is dimmed.

FIG. 4 shows the output status of the discharge lamp by timers A, B, and 17.18. Furthermore, Table 1 shows the results of measuring the starting time from when the inverter 2 starts operating until it lights up five times when a 40 W fluorescent lamp is used as the discharge lamp load when the light is dimmed in this way.

Table 1 As shown in Table 1, when the inverter 2 is operated in full light mode, there is a tendency for the electrodes of the fluorescent lamp to be insufficiently preheated and discharge starts, but when it is operated in dim mode, the lamp will turn on. It has been found that preheating can be performed sufficiently since it takes time to complete the heating process. In particular, the one-period switching element Q1. When the operation of Q2 was stopped, preheating was good, but stable lighting was obtained when the dimming operation after lighting was stopped for two cycles.

Therefore, during the period TA shown in FIG. 4 after the inverter 2 starts operating, the X contact of the timer A17 is set so that it operates with the signal from the Y terminal of the frequency dividing circuit 15 (stops one cycle and generates No. 1). Connect to the Y terminal side, and for subsequent dimming, connect the X contact to the Z terminal (
(generates a two-cycle stop signal) (see Figure 3 (f)
) and (a) condition).

Note that the above explanation is based on the case where the dimming degree is approximately 50 from the frequency dividing circuit 15.
%, but for example, the output signal of the frequency dividing circuit 15 may be converted into a signal whose duty cycle is not 50%. In addition, although the changeover switch 16 and the timers 17 and 18 are included in the control circuit 4 in the above example, they can be used to select the switch or the timers 17 and 18 by, for example, a transmission signal from the outside. It may also be possible to control the start of the operation.

In this way, when the discharge lamp 1 is started, the switching element Q
1. Since Q2 is repeatedly stopped, inverter 2
The discharge lamp 1 can be controlled without changing the output frequency of the discharge lamp 1, and the discharge lamp 1 can be started smoothly. In addition, since the inverter 2 does not control the light by stopping the operation of the switching element, QI, and Q2 for a certain period after a predetermined time has passed after the discharge lamp 1 is turned on, the electrodes of the discharge lamp 1 are heated to can do. Furthermore, even when lighting is dimmed, stable lighting can be achieved by turning on all lights in advance.

At this time, the period during which the switching elements Q+ and Q2 do not operate during startup is different from the period during which the switching elements do not operate during dimming.

FIG. 5 is a circuit diagram showing another embodiment of the invention. In the above embodiment, the case of a current resonant type inverter was explained, but it can of course also be applied to a voltage resonant type inverter in which a resonant circuit is configured by the inductance of a capacitor 21 and a transformer 22 as shown in FIG. It is. Furthermore, even when there is only one switching element, it is effective for an inverter including a resonant circuit (in this case, for example, it is not necessary to drive the switching element Q2).

Furthermore, as shown in FIG. 1, the switching element Q1. In the case where Q2 is connected in series, it is possible to use frequency-dividing dimming (it is also possible to control only one of the switching elements for No. 3. Furthermore, the inverter can be modified other than the above embodiment. The DC power source 3 may also be formed by methods other than rectifying and smoothing the commercial AC power source.It is also clear that the load may be a plurality of lamps connected in parallel or in series. It is.

Note that 23 in FIG. 5 is an inductor.

(Effects of the Invention) As explained hereinafter, according to the present invention, the switching elements of the inverter are repeatedly stopped for a period approximately an integral multiple of a half period of the output frequency of the inverter when starting the discharge lamp. The advantage is that the discharge lamp can be controlled without changing the bidirectional frequency of the inverter, and the discharge lamp can be started smoothly.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a circuit configuration diagram showing details of the control circuit in FIG. 1, and FIG. 3 is a circuit diagram showing the details of the control circuit in FIG.
Signal waveform diagram for explaining the operation of the circuit in Fig. 2 and Fig. 4.
The figure is a time chart showing the operation of the timer in Figure 2, and Figure 5.
The figure is a circuit diagram showing another embodiment of the present invention, and FIG. 6 is a circuit diagram of a conventional discharge lamp lighting device. 1.--Discharge lamp 2...--Inverter 3.--1 DC power source 4---Control circuit 8--1 Common installation circuit Q+, Q2 ``''''''Switching elements Same reference numerals in the figure indicate the same or equivalent part.

Claims (3)

[Claims] (1) In a discharge lamp lighting device that is equipped with an inverter and a resonant circuit that control a switching element connected to a DC power supply to generate a high-frequency voltage, and supplies a substantially sinusoidal high-frequency current to the discharge lamp, when the discharge lamp is started, , A discharge lamp lighting device characterized in that the switching element is repeatedly stopped for a period that is approximately an integral multiple of a half cycle of the frequency of the high-frequency voltage. (2) The discharge lamp lighting device according to claim 1, wherein the inverter stops the operation of the switching element and does not dim the light for a certain period after a predetermined period of time has elapsed after the discharge lamp is lit. (3) Claims 1 or 2, characterized in that the inverter makes the period during which the switching element stops operating during starting of the discharge lamp different from the period during which the switching element stops operating during dimming. The discharge lamp lighting device described.