JP2821844B2 - AC arc discharge lamp lighting power supply device and lighting method - Google Patents

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 with improved startup, and a lighting method thereof.

[0002]

2. Description of the Related Art Conventional power supplies for lighting metal halide lamps and mercury lamps include those shown in FIG.
This power supply device has an input terminal 1 connected to a commercial AC power supply.
And the rectifier 2 composed of diodes 3 to 6 rectifies the AC power supply and smoothes it with the capacitor 7. The smoothed DC 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 the output is fed to a reactor 12.
Smoothing is performed by the flywheel diode 13 and the smoothing capacitor 33. Inverter 1 including a smoothed DC power supply including switching elements 15 to 18 such as IGBTs
4 converts it into a rectangular wave AC having a frequency of 50 to 250 Hz, and the rectangular wave AC 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 denotes an inverter control device that supplies a drive signal to a switching element of the inverter 14, reference numeral 28 denotes a start signal terminal to which a start signal is input, and reference numeral 31 denotes a chopper control circuit that supplies a drive signal to the chopper 11.

In general, 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 denotes a high-frequency generator provided between the inverter 14 and the load 25. The high-frequency generator 31 applies a high frequency to the discharge lamp 25 at a high frequency when the discharge lamp 25 is started.
It's easy to start.

[0004]

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

[0005] The present invention has been improved 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 comprises a DC generator for rectifying an AC power supply, a reactor for smoothing the output of the generator, and at least one set of two switching elements connected in series. And an inverter for converting DC to AC and supplying AC to the discharge lamp, and a boosting capacitor in parallel with the inverter. The boosting capacitor is a capacitor that discharges energy of a reactor generated when two switching elements connected in series are short-circuited when the switching element is opened, charges the battery, and boosts the energy.

[0007] Further, DC generating means for rectifying an AC power supply, a reactor for smoothing the output of the DC generating means,
An inverter having at least one set of two switching elements connected in series and converting DC to AC and supplying AC to the AC arc discharge lamp, and a boost capacitor in parallel with the inverter are provided. When the lighting is started, the two switching elements connected in series are short-circuited to store energy in the reactor, and the energy is released to a capacitor provided in parallel with the input of the inverter by opening the switching elements. Then, the inverter input is boosted to light the discharge lamp.

[0008]

The AC power supply is rectified by the DC generation means and smoothed by the reactor. The smoothed DC is converted into a rectangular wave AC by an inverter of a switching element connected in series, and AC is supplied to the discharge lamp. A capacitor is provided in parallel with the inverter, and the switching elements connected in series at startup are short-circuited for a short time and then opened to boost the voltage applied to the 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 unit according to the present invention. The same reference numerals are given to the same parts as the conventional one shown in FIG. This power supply device differs 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. Except for this point, 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. Then, a capacitor having a small capacity is selected.

Now, 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, and 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 supplied to the inverter control circuit 27.
, First of the switching elements constituting the inverter, the switching elements 15 constituting the series circuit,
A drive signal is input to the switching element 16 or one of the switching elements 17 and 18. For example, switching elements 15, 16
When the drive signal is input to the switching elements 15, 16
Turns on. Thereby, 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
When the switches 5 and 16 are turned off, a voltage is induced in the reactor 12 in the direction of the arrow, and a current flows through the reactor 21 via the reactor 12, the diode 21, the capacitor 23, and the flywheel diode 13.

Assuming that Ts is the short-circuit time during which the switching elements 15 and 16 are turned on, L is the inductance of the reactor 12, E is the input voltage of the chopper 11, and I is the short-circuit current, I is proportional to E / L and Ts. . In addition, capacitor 2
Assuming that the capacitance of No. 3 is C and the voltage across the capacitor 23 is Vc, Vc is proportional to the 1/2 power of L / C and the short-circuit current I.
That is, the voltage Vc across the capacitor 23 is equal to the short circuit time T.
s, the energy stored in the reactor 12 is increased by increasing the short circuit time of the switching element,
3. Increase the charging voltage.

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 constituting inverter 14
8, or 16 and 17, a drive signal is input 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 this start-up, a high voltage of the input of the inverter 14 is applied to the discharge lamp 25, so that the discharge lamp 25 can be turned on. After the start of the discharge lamp 25, an AC having a frequency of 50 to 250 Hz is output from the inverter 14, and the discharge lamp is continuously lit.

In the above embodiment, a chopper for high-frequency switching is provided at the output of the DC generation means of the rectifier 2 in order to reduce the size of the reactor 12.
It is not necessary to increase the charging pressure of No. 3 and can be omitted.
In the above embodiment, the inverter 14 is a full-bridge inverter of the switching elements 15 to 18. However, a half-bridge inverter composed of two capacitors connected in series and two switching elements connected in series is used. Can also be applied. In the above embodiment, the rectifier 2 rectifies the alternating current. However, a rectifier may be provided, and a dc generator for rectifying and boosting the voltage may be used. The switching elements 15 to 18 are IGBTs.
Not only can it be applied to MOSFETs, bipolars, and transistors.

[0015]

As described above, according to the present invention, a capacitor that boosts the voltage of the reactor due to the energy of the reactor due to the short circuit of the switching element is provided, so that a high voltage can be applied to the discharge lamp at the time of starting, and the discharge lamp can be started reliably. Can be done. Further, in this start-up, the conventionally required high-frequency generation circuit becomes unnecessary, and the power supply device and the nearby electronic devices do not malfunction. Further, the boosting capacitor may be sufficiently smaller than the electrolytic capacitor used for the conventional smoothing capacitor.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an embodiment of a power supply device for lighting an AC arc discharge lamp of 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 generation means 11 Chopper 12 Reactor 13 Flywheel diode 14 Inverter 15, 16, 17, 18 Switching element 21 Diode 22 Current limiting element (resistance) 23 Boost capacitor 25 Load (discharge lamp) 26 Chopper control circuit 27 Inverter control circuit 28 Start signal input terminal

────────────────────────────────────────────────── ─── Continued on the front page Examiner Nobuyuki Seki (56) References JP-A-5-54990 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05B 41/14-14 / 29 H02M 7/48

Claims (2)

(57) [Claims] A DC generator for rectifying an AC power supply, a reactor for smoothing the output of the DC generator, and at least one set of two switching elements connected in series. An AC arc discharge lamp lighting power supply device having an inverter for supplying AC to an arc discharge lamp, wherein the reactor is provided in parallel with the inverter and is generated when the two switching elements connected in series are short-circuited at startup. A power supply device for lighting an AC arc discharge lamp, wherein a capacitor is provided for discharging the energy when the switching element is opened, charging and boosting the energy. 2. A DC generator for rectifying an AC power supply, a reactor for smoothing the output of the DC generator, and at least one set of two switching elements connected in series. In a lighting method of an AC arc lamp lighting power supply device having an inverter for supplying AC to an arc discharge lamp, at the time of starting lighting, short-circuiting the two switching elements connected in series to accumulate energy in the reactor. Opening the switching element, releasing the energy to a capacitor provided in parallel with the input of the inverter, boosting the input of the inverter, and starting and lighting the discharge lamp, for lighting an AC arc discharge lamp. How to turn on the power supply.