KR950005284B1 - Electronic stabilizer for metal halide lamp - Google Patents

Abstract

The stabilizer detects temperature variation and input voltage variation, keeps a constant lamp output to protect the metalhalide lamp and reduces the resonance at high frequency ignition. The stabilizer includes a power supply(10) which outputs main power(MS Vcc) and auxilliary power(B2), a reference voltage detection unit(11) which makes the output voltage constant, a variable frequency driving unit(12) which varies the output frequency, a power conversion unit(13) which varies the nominal output frequency, a temperature detection unit(17), a starting circuit(15), a lamp output unit(14), a output feedback unit(16).

Description

Electronic Ballasts for Metal Halide Lamps

1 is a circuit diagram of a conventional magnetic circuit ballast.

2 is a block diagram of an electronic ballast according to the present invention.

3 is a detailed circuit diagram of a power supply circuit applied to the apparatus of the present invention.

4 is an oscillation circuit diagram for driving an inverter applied to the apparatus of the present invention.

5 is a lamp output and a starting circuit diagram applied to the apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

10: power supply unit 10a: power filter circuit

10b: bridge rectifier 10c: high power factor smoothing circuit

10d: auxiliary power circuit 11: reference input voltage detector

12: variable frequency drive oscillator 13: power converter

14 lamp output 15 start circuit

16: output feedback unit 17: temperature detection circuit

18: low frequency generation unit 18a: logic driver

20-23: first to fourth snubber circuits R ₁ -R ₁₉ : resistance

C ₁ -C ₁₇ : condenser D ₁ -D ₁₂ : diode

Tr ₁ -Tr ₆ : transistor VR ₁ , VR ₂ : variable element

PM ₁ , PM ₂ : Potentiometer ZD ₁ -ZD ₄ : Zener Diode

VFC: Voltage / Frequency Converter LD: Divider

T ₁ , T ₂ : trans L ₁ , L ₂ : choke coil

Tra: Triac Sid: Sidak

LAMP: Metal halide lamp TS: Temperature sensor

T: Noise Filter Coil

The present invention relates to an electronic ballast for metal halide lamps, in particular to detect the input voltage fluctuations and temperature changes to convert to the corresponding output frequency to maintain the lamp output at the rated value to protect the metal halide lamp and lamp ballast, This is to eliminate the acoustic resonance when the high frequency is turned on.

In general, high-voltage discharge metal halide lamps have good color rendering and light conversion efficiency, and thus, as a substitute for sodium lamps, they are being used as show windows or indoor lighting for small outputs. It is a situation that is used a lot for collecting fish.

The conventional ballast for controlling the lighting of such a metal halide lamp has a choke coil L for limiting the current to the rated lamp current with a predetermined inductance value as shown in FIG. 1, and a high voltage pulse is superimposed on the peak value of the input voltage. And a metal halide lamp (LAMP) which emits light after the metal vapor is brought into a plasma state by the high pressure of the starter circuit (1).

The conventional lamp lighting control ballast constructed as described above superimposes the high voltage pulse generated at the start circuit 1 at the start of the input voltage to the peak value of the input voltage and applies a high voltage of 3 to 5 [kV] to the metal halide lamp LAMP. The internal metal vapor became a plasma state and the impedance in the light emitting tube was lowered so that the lamp lighting current was supplied and the metal halide lamp (LAMP) was turned on to stop the operation of the starting circuit (1).

However, the conventional ballast for metal halide lamps, for example, when used as a ballast for a catcher lamp has a high output of 1.5-3.5 [kW] and a lamp output of 10-20 [A]. As a result, the choke coil to limit this to the rated lamp current becomes relatively large.

Therefore, the iron core of copper coil and the weight and volume of copper wire are relatively large, which adversely affects the power loss caused by copper loss as well as the durability of the ballast due to severe heat generation, and also takes up a lot of installation area for easy management. Had a problem that did not.

Accordingly, an object of the present invention is to provide an input voltage fluctuation detection function and a temperature change detection function in consideration of the above-mentioned conventional problems, and to electronically circuit a series of processes for converting a lamp output to an output frequency so as to keep the lamp output at a constant rating. The goal is to significantly reduce volume, reduce power loss and extend the life of lamps and ballasts.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the electronic ballast of the present invention rectifies and smoothes an AC input power to output a DC main power source MS Vcc and a circuit operation auxiliary power source B ₂ , and the power source 10. A reference input voltage detector 11 which detects the main voltage MS Vcc output from the supply unit 10 and adjusts the impedance value correspondingly according to the change of the input frequency to obtain a uniform optical output voltage in a set range; The reference input voltage detector 11 includes a function of a variable frequency drive oscillator 12 for varying an output frequency so as to stabilize a light output change of a lamp according to a change in the input alternating voltage detected by the reference input voltage detector 11. And a power conversion circuit unit 13 which detects a voltage change and a temperature change of the temperature detection circuit unit 17 and converts it into a rated output frequency of the lamp, and detects an output temperature of the power conversion circuit unit 13 to perform a power conversion circuit. To the peak value of the output frequency voltage provided from the temperature detection circuit section 17 for compensating the conversion temperature so as not to be affected by the rated frequency output of the furnace section 13 and the variable frequency drive oscillation section 12 of the power conversion circuit section 13; By alternately switching the start circuit section 15 for superimposing the high voltage pulses and starting at high voltage, and the DC bias of the secondary voltage output from the power conversion circuit section 13, the balance of the polarization of the output voltage and magnetic flux density is balanced. A lamp output unit 14 for maintaining a constant and an output feedback unit 16 for feeding back the voltage output from the lamp output unit 14 to the variable frequency drive oscillation unit 12 of the power conversion circuit unit 13. It is composed of interconnections.

The power supply unit 10 is filtered by a power filter circuit 10a composed of a stage absorber (TNR), a noise filter coil (T), and a capacitor (C ₁ -C ₃ ) as shown in FIG. The high power factor smoothing circuit 10c including the variable power factor VR ₁ , the smoothing capacitors C ₄ and C ₅ , the diodes D ₁ and D ₂ , and the constant voltage diode ZD ₁ through the rectifying unit 10b. Auxiliary consisting of variable resistor (VR ₂ ), zener diode (ZD ₂ ), transistor (Tr ₁ ), diode (D ₃ , D ₄ ) and capacitor (C ₇ ) in addition to 250V of DC main voltage (M / S Vcc) The power supply circuit 10d is configured to obtain a constant voltage of DC 20V (B).

In addition, the temperature detecting circuit unit 17 includes a variable resistance VR ₂ for setting the reference potential, a temperature sensor TS, a constant voltage diode ZD ₃ , a capacitor C ₈ , and a resistor R as shown in FIG. 4. ₃ , R ₄ ), and the reference input voltage detection unit 11 includes a voltage divider R ₅ , R ₆ , a potentiometer PM ₁ , PM ₂ , a constant voltage diode ZD ₄ , and a capacitor C _9. ) And a diode (D ₅ ) and a resistor (R ₈ ), and the low frequency generating unit (18) is placed at the output terminal of the power conversion circuit unit (13) to remove the acoustic resonance caused by the high frequency when the lamp is lit. The power conversion circuit section 13 is configured to operate as a synthesized signal obtained by dividing the high frequency output of the voltage-frequency converter (VFC) into the necessary low frequency to be superimposed on.

In addition, the lamp output unit 14 includes a diode D ₉ -D ₁₂ , a capacitor C ₁₃ -C ₁₆ , and a resistor R ₁₆ -for each inverter transistor Tr ₃ -Tr ₆ , as shown in FIG. 5. R ₁₉ ) are respectively provided to configure the first to fourth on and off snubber circuits 20 to 23 in a full bridge method, and the first to fourth on and off snubber circuits 20 configured in the full bridge method are provided. The output of -23) is configured to be connected to the primary coil T ₂ a of the output transformer T ₂ through the capacitor C ₁₇ .

Referring to the accompanying drawings, the effects of the present invention configured as described above are as follows.

First, when AC input power is applied to the power filter circuit 10a of the power supply unit 10, as shown in FIG. 3, the surge voltage component is absorbed and removed by the surge absorber (TNR), and at the same time, the noise filter coil (T) and the capacitor are applied. Filter the noise of the AC component by (C ₁ -C ₃ ).

The AC power that has passed through the power filter circuit 10a is rectified by the bridge rectifier 10b to DC power and then smoothed by the high power factor smoothing circuit 10c to output a constant DC main voltage (M / S Vcc: 250V). Let's do it.

At the same time, the output terminal through the zener diode (ZD ₂ ), the diode (D ₄ ) and the capacitor (C ₆ , C ₇ ) is operated by the transistor (Tr ₁ ) of the auxiliary power supply circuit (10d) through the high power factor smoothing circuit (10c). In (B), the constant voltage (B: 20V) which is the drive power supply of each block circuit is output.

At this time, the reference input voltage detection unit 11 for detecting the DC main voltage (M / S Vcc) output from the power supply unit 10 as shown in Figure 4 potentiometer PM ₁ (PM ₂ ) and the divided voltage The potential set between the divided voltage by the resistors R ₅ and R ₆ and the zener voltage of the zener diode ZD ₄ is applied as the reference voltage at the middle tap terminal of the potentiometer PM ₁ .

Here, the reference voltage is an input (IN) signal of the voltage frequency converter (VFC) of the power converter 13, the output (OUT) frequency is adjusted according to the variable of the potentiometer (PM ₂ ), which is a variable frequency drive oscillator ( 12) The rated oscillation frequency is 43 [KHz], but the frequency-to-voltage ratio is 10 [kHz / V]. When the rated frequency is output, the input reference voltage of the VFC is set to 4.3V, so that In order to stabilize the light output change of the lamp (LAMP) and to increase the durability of the internal circuit, the output frequency is changed.

Therefore, in the variable frequency drive oscillation unit 12, the impedance value of the discharge lamp current limiting choke coil L ₂ of the starting circuit unit 15 of FIG. 5 decreases as the impedance increases and decreases as the frequency increases. Set the ratio of the voltage to 10 [KHz / V] and set the input reference voltage of the VFC when the rated frequency is output.When the rated DC voltage is 250V, the potentiometer PM ₁ of the reference input voltage detector 11 is When the voltage is adjusted to 4.3 V, the voltage frequency converter VFC of the power converter 13 converts the output to a rated oscillation frequency of 43 [KHz].

On the other hand, the temperature detection circuit unit 17 installed in the vicinity of the current amplifying output transistor Tr ₂ of the power conversion unit 13 adjusts the temperature of the output transistor Tr ₂ of the power conversion unit 13 as shown in FIG. 4. When the sensor detects the rated temperature at 70 ° C and adjusts the output to 4.3V with the variable resistor VR ₃ , it is applied to the input terminal IN of the power converter 13 through the diode D ₆ and the resistor R ₇ . However, by compensating the voltage according to the temperature change by the resistance values of the resistors R ₃ and R ₄ , the capacitor C ₈ , and the temperature sensor TS, the voltage is applied to the voltage frequency converter VFC of the power converter 13. When the voltage frequency converter (VFC) is compensated for the frequency for the temperature deviation operates to output only the rated frequency through the output terminal (OUT) as described above.

The high frequency output from the voltage frequency converter VFC is amplified by the current amplifying output transistor Tr ₂ and applied to the primary side coil of the coupling transistor T ₁ . It generates low frequency, that is, the ratio of high frequency and low frequency may vary according to the type of lamp, so divide the high frequency output (43KHz) of the voltage frequency converter (VFC) of the power converter 13 into 10 minutes, and divide 4.3 [KHz]. The low frequency of is synthesized to the high frequency output (43KHz) and applied to the output transistor (Tr ₂ ) through the diode (D ₈ ) to remove the acoustic resonance phenomenon generated when the metal halide lamp (LAMP) is turned on at high frequency Let it be.

On the other hand, the voltage induced in the secondary coil of the coupling transformer (T ₁ ) is a square wave signal, which is filtered by the choke coil (L ₁ ) as shown in FIG. The snubber circuit 20-23 is applied to the base of the full-bridge inverter transistors Tr ₃ -Tr ₆ , where a square wave signal is 'high' for transistors Tr ₃ and Tr ₆ , for example. If Tr ₄ and Tr ₅ are 'low', the second and third snubber circuits 21 and 22 are turned off, and the first and fourth snubber circuits 20 and 23 are turned on so that diodes D ₉ and D are turned on. ₁₂ ) and current through the capacitors C ₁₃ and C ₁₆ flows to the ground side.

In contrast, the square wave signal, the transistor (Tr _3, Tr ₆₎ is "low", the transistor (Tr _4, Tr ₅₎ is 'high', it operates in the above-described operation, as opposed to the diode (D _10, D ₁₁₎ and a capacitor ( The current through C ₁₄ and C ₁₅ flows to the ground side, so that the first to fourth snubber circuits 20 to 23 alternately switch, and each snubber circuit 20 to the switching operation is performed. At the output of 23), the primary coil of the output transformer T ₂ is switched at high speed through the capacitor C ₁₇ .

In this way, the high voltage of the secondary coil T ₂ b induced in the primary coil T ₂ a by the ultra-fast switching is applied to the metal halide lamp LAMP through the choke coil L ₂ for current limiting. When the high-voltage pulse generated from the starting circuit section 15 is superimposed at the peak position of the input voltage and the initial start is performed at a high voltage of about 3-5 [kV], the metal vapor in the light emission becomes plasma and the impedance in the light emitting tube is lowered. The lamp current is stably applied so that the operation of the start circuit unit 15 is stopped and the lamp LAMP is turned on.

As described above, the present invention has variable means for changing the voltage to satisfy both the condition caused by the voltage change and the condition caused by the temperature change, so that the impedance increases when the frequency increases, and decreases when the frequency increases, and thus the high range of the set range. The lamp can be turned on with a uniform light output even at low and low voltages, and the dual frequency protection configuration detects voltage fluctuations and temperature changes simultaneously. Not only can it be maintained at the rated voltage, but also when the metal halide lamp is turned on at high frequency, the acoustic resonance phenomenon can be eliminated by the low frequency generator, which can greatly contribute to the application of show window, indoor lighting, especially fishing boat.

Claims (5)

A power supply unit 10 for rectifying and smoothing the AC input power and outputting a DC main power source MS Vcc and each circuit operation auxiliary power source B ₂ , and a main voltage MS Vcc outputted from the power supply unit 10. A reference input voltage detector 11 that detects and adjusts an impedance value correspondingly to a change of an input frequency to obtain a uniform optical output voltage in a set range, and the input AC voltage detected by the reference input voltage detector 11. It includes a variable frequency drive oscillator 12 function for varying the output frequency to stabilize the light output change of the lamp in accordance with the fluctuation, and the voltage variation and temperature change of the reference input voltage detector 11 and the temperature detection circuit 17 A power conversion circuit section 13 for detecting and converting the lamp to a rated output frequency of the lamp, and detecting the output temperature of the power conversion circuit section 13 so as not to be affected by the rated frequency output of the power conversion circuit section 13. A temperature detection circuit section 17 for compensating for temperature and a start circuit section 15 for initializing at a high voltage by superimposing a high voltage pulse on a peak value of an output frequency voltage provided from the variable frequency drive oscillation section 12 of the power conversion circuit section 13; ) And a lamp output unit 14 which alternately switches the DC bias of the secondary voltage output from the power conversion circuit unit 13 to maintain a constant balance between the polarization of the output voltage and the magnetic flux density. Electronic ballast for the metal halide lamp, characterized in that the output feedback unit 16 for feeding back the final output voltage from the output unit 14 to the variable frequency drive oscillation unit 12 of the power conversion circuit 13 . The power supply unit 10 of claim ₁ is filtered by a power filter circuit 10a including a surge absorber (TNR), a noise filter coil (T), and a capacitor (C ₁ -C ₃ ), followed by a bridge rectifying unit (10b). DC power by the high power factor smoothing circuit (10c) consisting of the variable power factor (VR ₁ ), smoothing capacitor (C ₄ , C ₅ ), diodes (D ₁ , C ₂ ) and constant voltage diode (ZD ₁ ) Auxiliary power circuit consisting of variable resistor (VR ₂ ), zener diode (ZD ₂ ), transistor (Tr ₁ ), diode (D ₃ , D ₄ ) and capacitor (C ₇ ) in addition to 250V of voltage (M / S Vcc) An electronic ballast for metal halide lamps, characterized in that a constant voltage of DC 20V (B) is obtained by 10d). The temperature detecting circuit unit (17) according to claim 1, wherein the temperature detecting circuit unit (17) includes a variable resistor (VR ₂ ), a temperature sensor (TS), a constant voltage diode (ZD ₃ ), a capacitor (C ₈ ), and a resistor (R ₃ , R ₄ ) for setting a reference potential. Electronic ballast for metal halide lamp, characterized in that consisting of. 2. The reference input voltage detector 11 includes a voltage divider R ₅ , R ₆ , a potentiometer PM ₁ , PM ₂ , a constant voltage diode ZD ₄ , a capacitor C ₉ , and a diode. (D ₅ ) and a resistor (R ₈ ), and the low frequency generator 18 is placed at the output terminal of the power conversion circuit unit 13 so as to eliminate the acoustic resonance caused by the high frequency when the lamp is lit. An electronic ballast for a metal halide lamp, characterized in that the power conversion circuit unit (13) is operated as a synthesized signal obtained by dividing a high frequency output of a voltage-frequency converter (VFC) as necessary. 2. The lamp output unit 14 according to claim 1, wherein the lamp output unit 14 has a diode D ₉ -D ₁₂ , a capacitor C ₁₃ -C ₁₆ , and a resistor for each inverter transistor Tr ₃ -Tr ₆ , as shown in FIG. 5. R _{16 to} R ₁₉ are respectively provided to configure the first to fourth on and off snubber circuits 20 to 23 in a full bridge manner, and the first to fourth on and off snubber configured in the full bridge manner. The output of the circuit (20-23) is an electronic ballast for the metal halide lamp, characterized in that configured to be applied to the primary coil (T ₂ a) of the output transformer (T ₂ ) through a capacitor (C ₁₇ ).