KR940007437B1 - Electronic stabilizer - Google Patents

Abstract

The charged voltage of the condensers (1,2) connected to thyristors (SCR1-2) in parallel are discharged completely in instant during the period when the power is not provided so that the discharging angle is minimized and the high voltage pulse is maintained stable. The pulses are supplied for each period or each half period, then the initial start is performed quickly. Diodes (DIAC1-2) for constant voltage are connected to condensers (C3,4) in parallel so that the voltage variation is not affected to the circuit.

Description

Electronic ballast

1 is a conventional magnetic circuit ballast circuit diagram using a transformer.

2 is a schematic configuration diagram of the electronic ballast of the present invention.

3 is a block diagram of a high-pressure transformer used in the present invention.

4 is a circuit diagram of a half-cycle operation of the present invention.

5 is an overall circuit diagram of the present invention.

6 is a main waveform diagram of a high voltage transformer driving circuit of the present invention.

7 is a voltage waveform diagram applied to a lamp in the present invention.

* Explanation of symbols for main parts of the drawings

1, 4: Trigger signal generator 2: High voltage transformer driver

3: low pressure supply part ZNR1, ZNR2: varistor

D1 ~ 6: Diode C1 ~ 7: Condenser

R1 ~ 8: Resistance Diac1, Diac2: Diac

SCR1, SCR2: Dyistor ZD1, ZD2: Zener Diode

L1 ~ 3: Trans LAMP: Load Ramp

The present invention relates to an electronic ballast for igniting and holding a ballast, in particular a high-pressure discharge lamp such as mercury lamp, sodium lamp, metal lamp.

At present, the most widely used ballasts for high-pressure discharge lamps are magnetic circuit type. 1 shows the configuration of a ballast for a magnetic circuit type high-pressure discharge lamp using a transformer. In FIG. 1, the input alternating current (AC) voltage is supplied to the lamp via a condenser C via a high voltage transformer for ignition of the lamp. Here, the capacitor C serves to limit the supply current. Since the magnetic circuit ballast is connected to the lamp in series, the diameter of the copper wire should be more than a certain size to cover the entire current, and the iron core size of the transformer should be several tens of watts to several kilowatts. , Capacitor (C) must have a large capacity because the withstand voltage must be high. Therefore, magnetic circuit ballasts are too heavy and have a disadvantage of becoming too large. In addition, since part of the supplied power is hysterisis lost in the boost transformer, energy is wasted and heat is generated.

These magnetic circuit ballasts have been used so far despite the disadvantages of high power loss, too large and too heavy, but in recent years, the demand for power-saving applications is increasing due to the surge in power demand, especially for industrial and public use. Energy savings in electrical equipment are desperately expected. In accordance with this trend, in order to eliminate the power waste caused by the lighting characteristics of the high-pressure discharge lamp, there is an effort to convert the ballast structure for the high-pressure discharge lamp from the conventional magnetic circuit type to the electronic circuit type while the electronic ballast of the fluorescent lamp is commercialized. come.

An example of a conventional electronic ballast is an electronic ballast for a high-pressure discharge lamp disclosed in Patent Nos. 44 and 447, filed on January 7, 1989 and registered on September 19, 1991. However, this electronic ballast has a problem in that the high voltage part and the low pressure part operate at separate frequencies so that the trigger position is changed so that the high voltage is irregularly supplied every half cycle. In addition, since the ballast uses transistors for current control, only a part of the input is used during ignition and the rest is consumed by heat, resulting in inefficiency.It is difficult to control over 100W, and electrolytic capacitors are used for charging and discharging. Due to the characteristics of the electrolytic capacitor, a lot of heat is generated. Moreover, when the load stage is shorted, there are many problems such as the destruction of the transistor and the electrolytic capacitor due to the absence of special protection.

It is an object of the present invention to provide a highly reliable electronic ballast which is less affected by input voltage fluctuations and does not malfunction.

Another object of the present invention is to provide a compact and lightweight electronic ballast that can reduce power consumption.

Still another object of the present invention is to provide an electronic ballast that can easily start and turn on (ignite) the high voltage discharge lamp and minimize noise.

The above-described objects include: a low voltage supply for allowing an input rated voltage to be supplied directly to a load through an capacitor from an AC input power source, which is configured by connecting a capacitor limiting a current supplied to a load and a varistor which is a circuit protection element in parallel; The first capacitor is connected to the first terminal of the input AC power supply via the first diode, and the other end of the first capacitor is connected to the second terminal of the AC power supply via the second diode, and the primary side of the transformer Connect one end of the first winding to the connection point of the first diode and the first capacitor, connect the other end of the first winding to the first thyristor, the switching element, and connect the first series circuit of the resistor and the capacitor. Connect in parallel to the connection point of the primary side first winding and the first thyristor, symmetrically connect the second capacitor via the third diode to the second terminal of the input AC power supply, and connect the other end of the second capacitor to the fourth. Connect the first end of the primary side of the transformer to the connection point of the third diode and the second capacitor, and connect the other end of the second winding to the second die via a diode. Lister And a voltage charged in the first capacitor when the first dieistor is turned on by connecting a second series circuit comprising a resistor and a capacitor to the connection point of the second winding of the primary side and the second thyristor. The secondary winding is instantaneously discharged to generate a high voltage in the form of a pulse from the secondary winding of the transformer and is applied to the load.When the second dieistor is turned on, the voltage charged in the second capacitor is transferred to the secondary winding of the primary transformer. A transformer driving unit configured to discharge and generate a high voltage in a pulse form from the transformer secondary winding; A trigger signal generator for generating a trigger signal and applying the trigger signal to the gate of the second thyristor of the transformer driver in the first terminal of the input AC power supply; It is achieved by providing an electronic ballast including another trigger signal generator for generating a trigger signal when a second voltage of the input AC power is applied to the gate terminal of the first thyristor of the transformer driver.

Hereinafter, the present invention will be described with reference to the accompanying drawings as a preferred embodiment as follows.

2 is a schematic configuration diagram of the electronic ballast of the present invention, in which both ends of the input AC power supply are directly connected to a load lamp via a condenser C7 and simultaneously connected to a high voltage transformer driving circuit. Therefore, the input AC voltage is directly supplied to the lamp via the condenser C, and at the same time to the high voltage transformer driving circuit, and supplied to the lamp at a high voltage in the form of pulses through the transformer to start, light and maintain the lamp. Here, the varistors ZNR1 and ZNR2 act as circuit protection elements, and in the configuration of the transformer, the primary windings L1 and L2 and the secondary winding L3 are separated from each other, as shown in FIG. It is configured as shown in FIG.

4 is a circuit diagram of an electronic ballast for half cycle operation of the present invention. As shown, the electronic ballast includes a low pressure supply part 3, a transformer driver 2, and a trigger signal generator 1. The low voltage supply unit 3 is configured by connecting a capacitor C7 which limits the current supplied to the lamp and a varistor ZNR2, which is a circuit protection element, in parallel, and directly inputs an input rated voltage through the capacitor C7 from an input AC power supply. To feed. The transformer driving unit 2 connects the capacitor C1 to one terminal a of the input AC power via the diode D3, and the other end of the capacitor C1 is connected to the input AC power supply via the diode D2. The other end of the winding L1 is connected to the other terminal B, one end of the primary winding L1 of the transformer is connected to the connection point of the diode D3 and the capacitor C1, and the other end of the winding L1 is a thyristor which is a switching element. A series circuit composed of a resistor R7 and a capacitor C5 is connected in parallel to the connection point of the winding L1 and the thyristor. Here, the thyristor SCR1, which is a switching element, may be replaced with a transistor and a power-MOSFET. The trigger signal generator 1 sequentially connects the diode D6, the resistor R2, the resistor R4, the diode liquid Diac2, and the resistor R6 in series, and connects the zener diode ZD2 to the first resistor R2. ) And the capacitor C3 are connected in parallel to the connection point of the second resistor R4 and Diac2, and the diode D6 is connected to the other terminal of the input AC power source. (B), and the last resistor (R6) is connected to the gate terminal of the thyristor (SCR1) of the transformer driver (2).

5 is a circuit diagram of the present invention, showing the low voltage supply unit 3, the transformer driver 2, and the trigger signal generators 1, 4, respectively. Since the low pressure supply part 3 is the same as the structure shown in FIG. 4, it abbreviate | omits the description. The transformer driver 2 connects the first capacitor C1 to the first terminal a of the input AC power supply via the first diode D3, and connects the other end of the first capacitor C1 to the second diode ( Connect to the second terminal (B) of the input AC power supply via D2), and connect one end of the primary winding (L1) of the transformer to the connection point of the first diode (D3) and the first capacitor (C1), The other end of the first winding L1 is connected to the first thyristor SCR1, which is a switching element, and the first series circuit of the resistor R7 and the capacitor C5 is connected to the first winding L1 and the first winding. Parallel connection to the connection point of the thyristor SCR1, and symmetrically, the second capacitor C2 is connected to the second terminal B of the input AC power supply via the third diode D4, and the second capacitor Connect the other end of the to the first terminal a of the input AC power supply via the fourth diode D1, and connect one end of the second winding L2 of the primary side of the transformer to the third diode D4 and the second condenser. Connect the other end of the second winding L2 to the third dieistor SCR2, and connect the second series circuit of the resistor R8 and the capacitor C6. It is configured by connecting in parallel to the connection point of the second winding (L2) and the second thyristor (SCR2). The trigger signal generator 1 connects the diode D5, the resistor R1, the resistor R3, the diac 1, and the resistor R5 in series, and connects the zener diode ZD1 to the first resistor R1. ) And the capacitor C3 are connected in parallel to the connection point of the second resistor R3 and the diac1, and the diode D5 is connected to the second of the input AC power supply. The last resistor R5 is connected to the gate terminal of the second thyristor SCR2 of the transformer driver 2. The other trigger signal generator 4 is the same as the above-described configuration, except that the diode D6 is connected to the first terminal a of the input AC power supply and the last resistor R6 is the first die of the transformer driver 2. The connection to the gate terminal of the Lister SCR1 is different.

6 is a main waveform diagram of the high-voltage transformer driving circuit of the present invention, where a is an input power source, b is a voltage charged and discharged in the first capacitor C1, and a voltage integrated by the capacitor C4, d is The voltage charged and discharged in the second capacitor C2, e denotes a voltage integrated by the capacitor C3, and f denotes a high voltage pulse waveform supplied to the lamp through the high voltage transformer driver.

7 is a voltage waveform diagram applied to the lamp in the present invention, a is the input power, b is a high-pressure pulse supplied through the high-voltage transformer driver, c is the voltage applied to the lamp in the initial startup state, d is a stable Shows the voltage waveform taken.

Now, the operational effects of the electronic ballast of the present invention will be described with reference to FIGS. 4 and 5 and 6 and 7.

In FIG. 4, when a sinusoidal alternating current (AC) input as shown in a of FIG. 6 is applied, the input alternating current voltage is supplied directly to the lamp via the capacitor C7 of the low pressure supply unit 3, and at the same time, It is supplied to the drive part 2. When a positive voltage is applied to one terminal a of the input AC power source, i.e., during the first half wave of one cycle of the sinusoidal AC voltage shown in FIG. 6A, the capacitor C1 is charged and maintained, and then the thyristor which is a switching element. At the same time as the turn-on of SCR1, it discharges to the primary winding L1 of the transformer instantaneously to generate a high voltage in the form of a pulse at the secondary winding L3 of the transformer, which is applied to the lamp. . The turn-on operation of the above-described thyristors SCR1 is controlled by the trigger signal generator, when the + voltage is applied to the other terminal B of the input AC power source, that is, the sine wave AC shown in FIG. When the first half wave of one period of voltage ends and the next half wave starts, a constant voltage is applied to the second resistor R4 by the zener diode ZD2 and integrated as shown in C of FIG. 6 by the capacitor C4. Then, it becomes a trigger signal by the diac Diac2, and is applied to the gate terminal of the diester SCR1 via the last resistor R6, thereby turning on the diester SCR1. As described above, the application of the high pressure is repeated every cycle of the AC input voltage, so that the rated input voltage applied directly to the lamp via the capacitor C7 of the low voltage supply unit 3 and the high voltage in the form of a pulse are superimposed every cycle. Can be added to.

In FIG. 5, as in FIG. 4, when a sinusoidal alternating current (AC) input is applied, the rated input voltage is applied to the lamp via the capacitor C7 of the resistance supply section 3, and at the same time, the voltage is applied to the high voltage transformer driver. It is supplied to (2). When a positive voltage is applied to the first terminal a of the input AC power supply with respect to the sinusoidal AC input voltage, the first capacitor C1 is charged and maintained, and the first dieistor SCR1 serving as the switching element is turned on and The charging voltage of the first condenser C1 is instantaneously discharged to the primary side winding L1 of the transformer to generate a high voltage in the form of a pulse on the secondary side winding L3 of the transformer, and applies it to the lamp. When + voltage is applied to the second terminal B, the first capacitor C2 is charged and maintained, while the second diester SCR2 is turned on and the charging voltage of the second capacitor C2 is instantaneously transferred. It discharges to the primary side second winding L2 of and generates a high voltage in the form of a pulse on the secondary side winding L3 of the transformer and applies it to the lamp. At this time, the turn-on operations of the first and second thyristors SCR1 and SCR2 are controlled by the trigger signal generators 4 and 1, respectively, and trigger signals are generated by the trigger signal generators 1 and 4. The procedure is as described above. As described above, the process of applying a high voltage in the form of a pulse is repeated every half cycle of the AC input voltage, thereby directly applying to the lamp via the condenser C7 of the low voltage supply part 3, as shown in d of FIG. The voltage that superimposes the rated input voltage and high voltage in the form of pulse every half cycle can be applied to the lamp.

2, 4 and 5, the high pressure discharge lamp connected to the load is just one example in which the ballast of the present invention is used, for example, a boiler and various engines for igniting by applying a high pressure pulse in phase. It is also possible to connect an ignition device such as a load.

As described above, charging the capacitors C1 and C2 to generate a high pressure in the high voltage transformer driving circuit and then discharging the transformers L1 and L2 by the switching action of the thyristors SCR1 and SCR2 is most efficient. This is how it is generated. In other words, since the capacitor is connected in parallel with the thyristors SCR1 and SCR2, the charged voltage is instantaneously completely discharged in a period where no power is supplied, thereby minimizing the discharge angle and maintaining the high voltage pulse accurately. The generated high-voltage pulse is supplied to the load every cycle or every half cycle, so that the initial startup is quick and continuously applied even after the lighting (ignition), thereby effectively maintaining the lighting (ignition) state.

In addition, in the present invention, it is important that the trigger signal generator for discharging the charged voltage of the capacitors (C1, C2) at a certain position to ensure the stability of the trigger position. Conventional electronic ballasts for high-pressure discharge lamps are supplied with high pressure only at half cycles irregularly, causing severe flickering and sometimes turning off in the lit state. In order to solve this problem, in the present invention, the change in the position of the trigger is minimized with respect to the change in the input voltage so that the trigger is provided at the most suitable position. In other words, by connecting the constant voltage diodes (DIAC1, DIAC2) and the capacitors (C3, C4) in parallel, they are extremely insensitive to voltage fluctuations, and the diacs (DIAC1, DIAC2) are selected for the appropriate voltage to condenser (C3, C4). It discharges enough so that it does not malfunction. This generates a trigger every cycle or half cycle with the correct position.

In particular, the capacitor (C7) that is a device for supplying the appropriate power to the load in the present invention plays an important role to enable the present invention to reduce power. Unlike the limiting of the voltage boosted by the conventional magnetic circuit ballast through the condenser, it plays a role of lighting and maintaining the high-voltage discharge lamp by limiting the current required for the load by only the rated input voltage which is not boosted. As a result, a significant power saving is possible due to the difference between the boosted voltage and the unboost input voltage when supplying a constant current required for the lamp.

Furthermore, the present invention provides a high-voltage pulse every cycle or every half cycle even when directly supplying the rated input voltage and maintaining start-up and lighting (ignition), so that instant start-up and turn-on (ignition) are easy and light with low power consumption. It can maximize the power saving efficiency which keeps (ignition) state. In addition, it minimizes the flicker and noise of the lamp, and the weight and size are significantly smaller than the existing magnetic circuit type, and if there is little heat generation, the lighting (ignition) time and the restart time are shortened and the stability and efficiency of operation are excellent. .

Claims (8)

Low voltage supply unit for directly supplying the input rated voltage to the load through the capacitor C7 from an AC input power source formed by connecting the capacitor C7 limiting the current supplied to the load and the varistor ZNR2 as a circuit protection element in parallel. 3); Connect the capacitor C1 to the first terminal a of the AC power supply via the diode D3, and connect the other end of the capacitor C1 to the second terminal B of the AC power supply via the diode D2. ) And one end of the primary winding L1 of the transformer to the connection point of the diode D3 and the capacitor C1, and the other end of the winding L1 to the thyristor SCR1 as a switching element. The capacitor C1 is turned on when the die Lister SCR1 is turned on in parallel by connecting a series circuit composed of the resistor R7 and the capacitor C5 to a connection point of the primary winding L1 and the die Lister SCR1. A transformer driving unit 2 which discharges the voltage charged in the instant into the transformer primary winding L1 and generates a high voltage in the form of a pulse from the transformer secondary winding L3 and applies it to a load; A trigger signal is generated when a + voltage is applied to the second terminal B of the input AC power supply connected between the second terminal B of the input AC power source and the gate terminal of the thyristor SCR1 of the transformer driver 2. An electronic ballast comprising a trigger signal generator (1) applied to the gate of the thyristor (SCR1) of the transformer driver (2). The method of claim 1, wherein the trigger signal generator 1 connects the diode D6, the resistor R2, the resistor R4, the diac2, and the resistor R6 in sequence, and the zener diode ( ZD2) is connected in parallel to the connection point of the first resistor (R2) and the second resistor (R4), and the capacitor (C3) is connected in parallel to the connection point of the resistor (R4) and Diac2, the diode (D6) is input An electronic ballast configured to be connected to the second terminal (B) of the AC power source, and the last resistor (R6) is connected to the gate terminal of the thyristors (SCR1) of the transformer driver (2). The electronic ballast of claim 1, wherein the load is a high-pressure discharge lamp. The electronic ballast of claim 1, wherein the load is an ignition device. Low voltage supply unit for supplying the input voltage directly to the load through the capacitor C7 from an AC input power source formed by connecting the capacitor C7 for limiting the current supplied to the load and the varistor ZNR2 as a circuit protection element in parallel. 3); The first capacitor C1 is connected to the first terminal a of the input AC power supply via the first diode D3, and the other end of the first capacitor C is connected to the first terminal A of the input AC power supply via the second diode D2. To the second terminal (B), connect one end of the primary winding (L1) of the transformer to the connection point of the first diode (D3) and the first capacitor (C1), and The other end is connected to the first die thyristor SCR1 serving as a switching element, and the first series circuit composed of the resistor R7 and the capacitor C5 is connected to the first winding L1 and the first die thruster SCR1. The second capacitor C2 is connected symmetrically to the second terminal B of the input AC power supply via the third diode D4, and the other of the second capacitor C2 One end is connected to the first terminal a of the input AC power supply via the fourth diode D1, and one end of the second winding L2 of the primary side of the transformer is connected to the third diode D4 and the second capacitor C2. Of) To the fault, connect the other end of the second winding L2 to the second dieistor SCR2, and connect the second series circuit of the resistor R8 and the capacitor c6 to the second winding L2. ) And the voltage charged in the first condenser C1 is trans-primary-side first winding L1 when the first die Lister SCR1 is configured to be connected in parallel to the connection point of the second die lister SCR2. Discharge to generate a high voltage in the form of a pulse from the transformer secondary winding (L3) to be applied to the load, and when the second die Lister (SCR2) is turned on, the voltage charged in the second capacitor (C2) A transformer driver 2 for discharging the second winding L2 to generate a high voltage in a pulse form at the transformer secondary winding L3 and applying it to a load, and the first terminal a of the input AC power source and the transformer driver 2. 2 Trigger trigger when + voltage is applied to the first terminal a of the input AC power supply connected between the gate terminals of the Is generated by the first trigger signal generator (1) and the second terminal (B) of the input AC power supply and the transformer driver (2) to be applied to the gate of the second thyristor (SCR2) of the transformer driver (2). A trigger signal is generated when a + voltage is applied to the second terminal B of the input AC power supply connected between the gate terminals of the first thyristor SCR1 and applied to the gate terminal of the first thyristor of the transformer driver 2. Electronic ballast comprising a second trigger signal generator (4). The method according to claim 5, wherein the first trigger signal generator (1) connects the diode (D5), the resistor (R1), the resistor (R3), the die solution (Diac1), and the resistor (R5) in sequence. In addition, the Zener diode ZD1 is connected in parallel to the connection point of the first resistor R1 and the second resistor R3, and the capacitor C3 is connected in parallel to the connection point of the second resistor R3 and Diac1. D5) is connected to the first terminal a of the input AC power supply, the last resistor R5 is configured to be connected to the gate terminal of the second thyristor SCR2 of the transformer driver 2, and the second trigger signal generator (4) the diode D6, the resistor R2, the resistor R4, the diac2 and the resistor R6 are connected in series, and the zener diode ZD2 is connected to the first resistor R2 and the second resistor in this order. The capacitor C3 is connected in parallel with the connection point of the resistor R4 and the diac2, and the diode D6 is connected to the second terminal B of the input AC power supply. And the last resistor (R6) is connected to the gate terminal of the first thyristor (SCR1) of the transformer driver (2). The electronic ballast of claim 5, wherein the load is a high pressure discharge lamp. The electronic ballast of claim 5, wherein the load is an ignition device.