JPH09245975A - Power supply device for high pressure discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device for high pressure discharge lamp, which can establish lighting with a stable illuminance despite varying supply voltage or supply frequency by sensing the voltage and current to be fed to the discharge lamp, and performing a constant power control. SOLUTION: Through a series capacitor 34 a high pressure mercury lamp 33 is connected with the output side of an electric leak transformer 13, and a voltage sensing circuit 15 and a current sensing circuit 14 are provided for measuring the load voltage and load current of the lamp. The outputs of these sensing circuits 14 and 15 are fed to a control device 16 having a built-in microcomputer to serve for the control of turning on and off a transistor in an inverter circuit 12, and the AC voltage which is PWM modulated is controlled. When the discharge lamp 33 is lighted and a stable condition is established, the lamp voltage V is measured followed by measurement of the current I, and VxI is calculated. the obtained result is compared with a predetermined reference power value P, and if VI<P, a command is given to the inverter circuit 12 so as to heighten the output power to one stage up. In the opposite case, a command to down one stage is given, and it is possible to establish a stable dimming of the lamp.

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 a high pressure discharge lamp, such as a high pressure mercury lamp using an inverter circuit.

[0002]

2. Description of the Related Art In order to light a conventional discharge lamp such as a high pressure mercury lamp, it is necessary to cause an arc discharge. However, since the arc discharge has a drooping load characteristic, it is appropriate for a load impedance that changes drastically. A power supply that supplies current and voltage is required, and a commercial power supply to which a series reactor called a ballast is connected is usually used.
Further, when the discharge lamp is turned on, a starting circuit for heating the opposite electrode as a heater or applying a high voltage is specially provided.

[0003]

However, the series reactor system has a drawback in that the lamp characteristics, that is, the illuminance, greatly changes depending on the power supply frequency and the power supply voltage. Therefore, manufacturers of discharge lamps prohibit the use of constant-current type power supplies whose power supply voltage varies, and the series reactor method uses power supply voltage within ± 5% and power supply frequency within ± 2%. However, it was very difficult to use the discharge lamp with the generator power supply used in fishing boats and construction sites. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power supply device for a high-pressure discharge lamp that can be used even when the frequency or voltage of the power supply fluctuates.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
The power supply device for a high-pressure discharge lamp described above, an inverter circuit for generating a PWM-modulated alternating current of a predetermined frequency, and an output of the inverter circuit as a primary side input, and a high-pressure discharge lamp as a load is connected to the secondary side. A leakage transformer, a voltage detection circuit and a current detection circuit for respectively detecting a voltage and a current applied to the high-pressure discharge lamp, an output of the voltage detection circuit and an output of the current detection circuit as inputs, and constant power control of the inverter circuit And a control device for performing. The power supply device for a high pressure discharge lamp according to claim 2 is the power supply device for a high pressure discharge lamp according to claim 1, wherein the constant power control of the inverter circuit changes a width of a carrier wave of a PWM modulation (pulse width modulation) wave. I am doing it. The power supply device for a high pressure discharge lamp according to claim 3 is the power supply device for a high pressure discharge lamp according to claim 1 or 2, wherein the reference power value of the constant power control is changed to dimming the high pressure discharge lamp. It is carried out. The power supply device for a high pressure discharge lamp according to claims 1 to 3 can be applied regardless of whether the input power supply is three-phase or single-phase.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to the attached drawings, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention. 1 is an electric wiring diagram of a power supply device for a high pressure discharge lamp according to an embodiment of the present invention, FIG. 2 is a sectional view of a leakage transformer, FIG. 3 is a voltage waveform diagram on the output side of the leakage transformer, and FIG. Is a graph showing the relationship between illuminance and voltage, and FIG. 5 is an operation flow chart.

As shown in FIG. 1, a high-pressure discharge lamp power supply device 10 according to an embodiment of the present invention includes a rectifying unit 11 having a three-phase AC power source as an input, and a DC from the rectifying unit 11 to P.
An inverter circuit 12 that produces WM-modulated alternating current, a leakage transformer 13 connected to the inverter circuit 12, a current detection circuit 14 and a voltage detection circuit 15 provided on the output side of the leakage transformer 13, and a controller 16 for these. And have. Hereinafter, these will be described in detail.

The rectifying section 11 has a three-phase bridge circuit 17 having six diodes, and a smoothing circuit 20 having a reactor 18 and a capacitor 19 connected to the output side thereof. Further, the noise absorbing capacitors 21 to 23 and the varistors 24 to 26 are connected to the input side of the three-phase bridge circuit 17, and the noise absorbing capacitor 27 is also connected to the output side of the three-phase bridge circuit 17. A discharge resistor 28 is connected to the condenser 19 of the smoothing circuit 20. The rectification unit 11 obtains a direct current with less ripple and noise from the three-phase power supply.

The inverter circuit 12 is composed of a well-known bridge type circuit using four transistors.
A 533 Hz AC A is PWM-modulated as shown in FIG. The individual carrier waves B forming the alternating current A have a frequency of 15990 Hz, and the width thereof is controlled for each time to synthesize a sinusoidal alternating current. In FIG. 3, the number of carrier waves B is reduced to about 1/5 for easier understanding. A driver 29 is connected to the base of the transistor of the inverter circuit 12. The driver 29 is operated by a signal from the control device 16 controlled by the microcomputer.

As shown in FIG. 2, a leakage transformer 13 having a gap 30 is connected to the output side of the inverter circuit 12, and the voltage of 200 V applied to the primary coil 31 is increased by increasing the number of turns of the secondary coil 32. It is boosted to 300V. FIG. 3 shows an outline of the output voltage waveform of the leakage transformer 13, in which the high voltage pulse C is on the rising and falling portions of each carrier wave B. This high voltage pulse C
Is a high-pressure mercury lamp 3 which is an example of a high-pressure discharge lamp under no load
At the lighting start time of 3, the PWM modulated sine wave is about 1
Since a pulse voltage of about 500 V is applied, the starting circuit of the high pressure mercury lamp 33 can be omitted. Since the alternating current converted by the electric leakage transformer 13 is 533 Hz, the device can be formed smaller and lighter than the conventional series reactor and transformer.

A high pressure mercury lamp 33 is connected to the output side of the electric leakage transformer 13 via a series capacitor 34.
A current detection circuit 14 and a voltage detection circuit 15 that measure the load voltage and the load current, respectively, are provided. The current detection circuit 14 is a current transformer (CT) 35 and a current detection module 3 for converting its output signal into a digital signal.
6, and the voltage detection circuit 15 includes a voltage transformer (PT).
37 and a voltage detection module 38 for converting its output signal into a digital signal.

Outputs from the current detection circuit 14 and the voltage detection circuit 15 are input to a control device 16 having a microcomputer therein to control ON / OFF of a transistor of the inverter circuit 12 to generate a PWM-modulated AC voltage. Have control. This control method will be described with reference to FIG. 5. When the high-pressure mercury lamp 33 lights up and enters a steady state, first the lamp voltage V
Is measured (step S1), and then the lamp current I is measured (step 2). Then, V × I is calculated (step S3) and compared with a constant power value P which is a preset reference power value (step S4). And VI <P
In the case of, a command is issued to the inverter circuit 12 to increase the output voltage by one step (step S5), and in the case of VI> P, an instruction is issued to the inverter circuit 12 to decrease the output voltage by one step (step S5). S6). The reference power value P can be changed from the outside so that stable dimming of the high pressure mercury lamp can be performed.

By performing such control, the electric power supplied to the high-pressure mercury lamp 33 is kept constant, so that the high-pressure mercury lamp 3 is stable even if the input voltage and the input frequency fluctuate.
3 is being discharged. In addition, since the power factor of the discharge lamp is almost 1 at 400 Hz or higher, the power consumption can be accurately obtained by independently measuring the voltage and the current and calculating the product. In FIG. 1, reference numeral 39 denotes a power supply circuit, which converts a single-phase commercial power supply, which has been converted to a predetermined voltage from the transformers 40 and 41, into a direct current, and which is used as a current detection module 36, a voltage detection module 38, and a driver 2.
9, supplied to the controller 16. Reference numeral 42 indicates a pilot lamp.

[0013]

EXAMPLE FIG. 4 shows a power supply device 10 for a high pressure discharge lamp according to an embodiment of the present invention, which has a specified lamp capacity of 2500.
When the high pressure mercury lamp 33 of w is turned on, the experimental result of measuring the illuminance when the same high pressure mercury lamp 33 is turned on by the conventional method is shown. In the high-pressure discharge lamp power supply device 10 according to the embodiment, it is possible to secure a constant illuminance even when the power supply voltage fluctuates in a wide range. Further, a high-pressure discharge lamp such as a high-pressure mercury lamp has a high resistance inside as the usage time is extended. In this case as well, a constant power is maintained while measuring the power VI using the current detection circuit 14 and the voltage detection circuit 15. Since the supply is controlled so that it can be controlled so as to exhibit stable performance even when the high-pressure discharge lamp becomes old.

[0014]

As is apparent from the above description, the power supply device for a high pressure discharge lamp according to claims 1 to 3 performs constant power control by detecting the voltage and current supplied to the high pressure discharge lamp. Therefore, even with a power supply whose power supply voltage and power supply frequency fluctuate, like a generator of a fishing boat, it is possible to illuminate with stable illuminance. Further, since the alternating current is PWM-modulated by the inverter circuit and the leakage transformer is provided in the middle, a high voltage is supplied to the load, whereby the conventionally used lighting circuit of the discharge lamp can be omitted. In particular, the power supply device for a high pressure discharge lamp according to claim 3 performs dimming while changing the reference value while performing constant power control, so that stable dimming of the high pressure discharge lamp can be performed.

[Brief description of drawings]

FIG. 1 is an electrical wiring diagram of a power supply device for a high pressure discharge lamp according to an embodiment of the present invention.

FIG. 2 is a sectional view of a leakage transformer.

FIG. 3 is a voltage waveform diagram on the output side of the leakage transformer.

FIG. 4 is a graph showing the relationship between illuminance and voltage.

FIG. 5 is an operation flowchart.

[Explanation of symbols]

10 Power Supply Device for High-Pressure Discharge Lamp 11 Rectifier 12 Inverter Circuit 13 Leakage Transformer 14 Current Detection Circuit 15 Voltage Detection Circuit 16 Control Device 17 Three-Phase Bridge Circuit 18 Reactor 19 Capacitor 20 Smoothing Circuit 21 Capacitor 22 Capacitor 23 Capacitor 24 Varistor 25 Varistor Star 26 Varistor 27 Condenser 28 Discharge resistance 29 Driver 30 Gamp 31 Primary coil 32 Secondary coil 33 High pressure mercury lamp 34 Series capacitor 35 Current transformer 36 Current detection module 37 Voltage transformer 38 Voltage detection module 39 Power circuit 40 Transformer 41 Transformer 42 pilot lamp

Claims (3)

[Claims] 1. An inverter circuit for generating a PWM-modulated alternating current having a predetermined frequency, a leakage transformer to which an output of the inverter circuit is used as a primary side input, and a high pressure discharge lamp as a load is connected to the secondary side, A voltage detection circuit and a current detection circuit for respectively detecting a voltage and a current applied to the high-pressure discharge lamp, and a control device which receives the output of the voltage detection circuit and the output of the current detection circuit as input and performs constant power control of the inverter circuit. A power supply device for a high-pressure discharge lamp, comprising: 2. The constant power control of the inverter circuit is P
The power supply device for a high pressure discharge lamp according to claim 1, which is performed by changing a width of a carrier wave of the WM modulated wave. 3. The power supply device for a high pressure discharge lamp according to claim 1, wherein dimming of the high pressure discharge lamp is performed by changing a reference power value of the constant power control.