JPH0778695A - Power supply device for lighting ac arc discharge lamp and lighting method for lamp - Google Patents

Abstract

PURPOSE:To provide a power supply device which clan easily start a metal halide lamp and AC mercury lamp, with which provision of a high frequency generating device is omitted. CONSTITUTION:This device comprises a DC producing means 2 through rectification of AC power supplied, a reactor 12 to smooth the output of the DC producing means, an inverter 14 having at least one set of serially connected switching elements 15, 16 or ones 17, 18 and converting the DC into AC which is to be supplied to a discharge lamp 25, and a boosting capacitor 23 laid in parallel with the inverter 14. The capacitor 23 charges the energy accumulated in the reactor when the two switching elements 15, 16 or the ones 17, 18 are shortcircuited and a high voltage when they 15, 36 or 17, 18 are off so that high voltage is impressed on the inverter to facilitate start lighting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for an AC arc discharge lamp such as a metal halide lamp and an AC mercury lamp, which has been improved in starting, and a lighting method thereof.

[0002]

2. Description of the Related Art A conventional power source device for lighting a metal halide lamp and a mercury lamp is shown in FIG.
This power supply device has an input terminal 1 connected to a commercial AC power supply.
The AC power source is rectified by the rectifier 2 having the diodes 3 to 6 and smoothed by the capacitor 7. The smoothed direct current is repeatedly turned on and off at a frequency of 15 to 20 kHz by a chopper 11 composed of a switching element such as an IGBT, and its output is output to the reactor 12,
Smoothing is performed by the flywheel diode 13 and the smoothing capacitor 33. Inverter 1 in which a smoothed DC power supply is composed of switching elements 15 to 18 such as IGBTs
4 converts into a rectangular wave alternating current having a frequency of 50 to 250 Hz, and the rectangular wave alternating current is supplied to an AC arc discharge lamp such as a metal halide lamp or a mercury lamp of the load 25. In addition,
Reference numeral 27 is an inverter control device that supplies a drive signal to the switching element of the inverter 14, 28 is a start signal terminal to which a start signal is input, and 31 is a chopper control circuit that supplies a drive signal to the chopper 11.

Generally, an AC arc discharge lamp such as a metal halide lamp and a mercury lamp cannot be started unless a high voltage is applied at the time of starting. Reference numeral 31 is a high frequency generator provided between the inverter 14 and the load 25, and applies a high voltage to the discharge lamp 25 at high frequency when the discharge lamp 25 is started.
Makes it easier to start.

[0004]

However, since the high-frequency generator 31 generates a high-frequency high voltage, the power supply device itself and electronic devices near the power supply device become noise, causing these devices to malfunction.

The present invention has been improved so as to easily start an AC arc discharge lamp such as a metal halide lamp and a mercury lamp, except for a high frequency generator.

[0006]

The present invention has a direct current generating means for rectifying an alternating current power source, a reactor for smoothing the output of the generating means, and at least one set of two switching elements connected in series. An inverter that converts direct current into alternating current and supplies alternating current to the discharge lamp, and a boosting capacitor in parallel with the inverter are provided. The boosting capacitor is a capacitor that releases the energy of the reactor generated when two switching elements connected in series are short-circuited and charges the boosted voltage when the switching element is opened.

Further, a direct current generating means for rectifying the alternating current power source, a reactor for smoothing the output of the direct current generating means,
An inverter having at least one set of two switching elements connected in series and converting direct current into alternating current to supply alternating current to an alternating current arc discharge lamp, and a boosting capacitor are provided in parallel with the inverter. When the lighting is started, the two switching elements connected in series are short-circuited to store energy in the reactor, and by opening the switching element, the energy is released to a capacitor provided in parallel with the input of the inverter. Then, the voltage of the inverter input is increased to light the discharge lamp.

[0008]

The AC power supply is rectified by the DC generator and smoothed by the reactor. The smoothed direct current is converted into a rectangular wave alternating current by the switching element inverter connected in series, and the alternating current is supplied to the discharge lamp. A capacitor is provided in parallel with the inverter, and the switching elements connected in series at the time of start-up are short-circuited for a short time and then opened to boost the voltage applied to this capacitor. The boosted capacitor voltage is applied to the inverter, the high voltage converted by the inverter is applied to the discharge lamp, and the discharge lamp is started.

[0009]

FIG. 1 shows an embodiment of a power supply device according to the present invention. The same parts as those of the conventional one shown in FIG. 2 are designated by the same reference numerals. This power supply device is different from the conventional power supply device in that a parallel circuit of a diode 21 and a current limiting resistor 22 and a series circuit of a capacitor 23 are provided in parallel at the input of the inverter 14, and a high frequency generator 31 is used. Except for this, an inverter control circuit that outputs a drive signal at the time of startup different from the drive signal of the conventional inverter control circuit 32 is provided. The capacitor 23 having a small capacity is selected.

When a start signal is input to the start signal input terminal 28, a signal is input to the chopper control circuit 26, the chopper 11 is turned on, smoothed by the reactor 12 and the flywheel diode 13, and a DC voltage is supplied to the inverter 14. Apply. When the chopper 11 is turned on, the capacitor 23 is charged via the diode 21. The maximum value of the voltage at this time is equal to the output voltage of the chopper 11.

On the other hand, the start signal is the inverter control circuit 27.
First, among the switching elements forming the inverter, the switching elements 15 forming the series circuit,
The drive signal is input to either 16 or the switching elements 17 and 18. For example, the switching elements 15 and 16
When a drive signal is input to the switching elements 15 and 16
Turns on. As a result, the chopper 11 and the reactor 1
2, a current flows through the rectifier via the switching element 15 and the switching element 16, and energy is accumulated in the reactor 12. Then, the drive signals of the switching elements 15 and 16 are turned off in a short time Ts. Switching element 1
By turning off 5 and 16, a voltage is induced in the reactor 12 in the direction of the arrow, and a current flows in the reactor 21 via the reactor 12, the diode 21, the capacitor 23, and the flywheel diode 13.

Assuming that the short-circuit time when the switching elements 15 and 16 are turned on is Ts, the inductance of the reactor 12 is L, the input voltage of the chopper 11 is E, and the short-circuit current is I, I is proportional to E / L and Ts. . Also, the capacitor 2
3 is C and the voltage across the capacitor 23 is Vc, Vc is proportional to L / C 1/2 power and the short circuit current I.
That is, the voltage Vc across the capacitor 23 is the short circuit time T
In proportion to s, the short-circuit time of the switching element is lengthened to increase the energy stored in the reactor 12,
Increase the charging voltage to 3.

As a result, the voltage across the capacitor 23 can be made high, and a high no-load voltage can be applied to the inverter 14 via the current limiting resistor 22. Next, switching elements 15 and 1 which constitute the inverter 14
8 or 16 and 17 inputs a drive signal from the inverter control circuit 27, and the switching elements 15 and 18 or 16
And 17 are turned on, and a voltage is applied to the discharge lamp 25. At the time of this start-up, a high voltage input to the inverter 14 is applied to the discharge lamp 25, so that the discharge lamp 25 can be turned on. After starting the discharge lamp 25, the inverter 14 outputs an alternating current having a frequency of 50 to 250 Hz to continuously light the discharge lamp.

In the above embodiment, the output of the direct current generating means of the rectifier 2 is provided with the chopper for high frequency switching in order to downsize the reactor 12, but the capacitor 2
It is unnecessary to increase the charging pressure of No. 3 and can be removed.
Further, in the above-described embodiment, the full bridge type inverter of the switching elements 15 to 18 is used for the inverter 14, but a half bridge type inverter composed of two capacitors connected in series and two switching elements connected in series is used. Can also be applied. Further, in the above embodiment, the rectifier 2 is used to rectify the alternating current, but a boost converter may be provided and a direct current generating means for boosting after the rectification may be used. The switching elements 15 to 18 are IGBTs.
Not only can it be applied to MOSFET, bipolar, and transistor.

[0015]

As described above, according to the present invention, since the capacitor for boosting the energy of the reactor due to the short circuit of the switching element is provided, a high voltage can be applied to the discharge lamp at the time of starting, and the discharge lamp can be reliably started. Can be made. Further, in this start-up, the high-frequency generation circuit, which has been necessary in the past, is no longer necessary, and the power supply device and the electronic equipment in the vicinity do not malfunction. Further, the boosting capacitor may be sufficiently smaller than the electrolytic capacitor used in the conventional smoothing capacitor.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of a power supply device for lighting an AC arc discharge lamp according to the present invention.

FIG. 2 is a schematic block diagram of a conventional power supply device for lighting an AC arc discharge lamp.

[Explanation of symbols]

 2 DC generating means 11 Chopper 12 Reactor 13 Flywheel diode 14 Inverter 15, 16, 17, 18 Switching element 21 Diode 22 Current limiting element (resistor) 23 Boosting capacitor 25 Load (discharge lamp) 26 Chopper control circuit 27 Inverter control circuit 28 Start signal input terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Tsujii 2-14-3 Awaji, Higashiyodogawa-ku, Osaka City, Osaka Prefecture Sansha Electric Co., Ltd.

Claims (2)

[Claims] 1. A direct current generating means for rectifying an alternating current power source, a reactor for smoothing the output of the direct current generating means, and at least one set of two switching elements connected in series, which convert direct current into alternating current and convert it into alternating current. In an AC arc discharge lamp lighting power supply device having an inverter that supplies AC to the arc discharge lamp, the reactor that is provided in parallel with the inverter and that is generated when the two switching elements connected in series at startup are short-circuited. A power supply device for lighting an AC arc discharge lamp, which is provided with a capacitor that releases the energy of the above-mentioned energy when the switching element is opened to charge and boost the voltage. 2. A direct current generating means for rectifying an alternating current power source, a reactor for smoothing an output of the direct current generating means, and at least one set of two switching elements connected in series, the direct current being converted into an alternating current and the alternating current being exchanged. In a lighting method of a power supply device for lighting an AC arc discharge lamp, which comprises an inverter for supplying AC to the arc discharge lamp, at the time of lighting start, the two switching elements connected in series are short-circuited to store energy in the reactor. For discharging an AC arc discharge lamp by releasing the switching element to release the energy to a capacitor provided in parallel with the input of the inverter to boost the inverter input to start the discharge lamp. How to turn on the power supply.