RU1817266C - Device for striking short-arc high-pressure metal-halogen discharge lamp - Google Patents

Abstract

Usage: lighting devices of vehicles and aircraft. SUMMARY OF THE INVENTION: A device for igniting a short-arc metal halide discharge lamp comprises a power supply with a falling volt-ampere characteristic, a pulse generator, a transformer, a threshold element with a hysteresis characteristic, the switching threshold of which is higher than the lamp operating voltage, and the switching threshold is higher than the initial voltage of the lamp . 1 s.p. , 3 ill.

Description

The present invention relates; 6 to electrical engineering, in particular to devices for igniting high-pressure gas discharge lamps (HLV) with metal vapors, for example, short-arc metal-gas lamps (MGL), powered from direct current sources and used in the headlights of automobiles, in on-board light fixtures and signal lights of vehicles or aircraft

The purpose of the invention is to simplify the electrical circuit of the device.

The invention is illustrated in the drawings, wherein FIG. 1 is a block functional diagram of a lamp power and ignition device; in FIG. 2 and 3 are examples of specific implementation and implementation of the proposed ignition device.

In FIG. 1 shows a block-functional electric circuit for supplying and igniting a lamp, where the ignition device 1 is a short-arc high-pressure low-pressure gas cylinder 2 without

The preheating of the electrodes is connected to a secondary power supply source 3 having a stabilized output current, or supplying a current-voltage characteristic that is powered from a low-voltage direct current network or from a battery 4. Ignition device 1 is assembled, for example, according to the circuit blocking generator with self-excitation and contains a power transistor 5, increasing the autotransformer b with a primary winding 7, a secondary winding 8 and a feedback winding 9 connected at one end to the base of the transistor RA 5 through a resistor 10, and the other end to the cathode of the Diode 11, in parallel connected. roc capacitor 12 connected to the negative power bus 13, the diode 14 of the starting circuit with a cathode connected to the base of the transistor 5 and the anode to the power bus 13, the starting circuit 15 connected between the positive power bus 16 and the negative power bus 13 and connected to the base

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transistor 5, the emitter of which is connected to the negative power bus 13, the protection circuit 17, which is connected to the collector of the transistor 5, to the midpoint between the windings 7 and 8 of the autotransformer b and connected to the power bus 13 and 16, moreover, the autotransformer b is at one end of the output wrap 8 is connected to the first electrode of the lamp 2, the other electrode which is connected to the negative bus 13, and the second end of the winding 8 is connected to one end of the winding 7 and the collector of the transistor 5, and the other end of the winding 7 of the autotransformer b is connected to positive power bus 16.

The lamp ignition device operates as follows.

The feedback circuit (elements 9, 10, 11,12,14), providing the conditions for the self-generation of the blocking generator, periodically opens and closes the transistor 5, while the current flowing through the transistor and the primary winding 7 of the autotransformer b causes the induction of high voltage pulses at the output of device 1, which light the lamp 2.

The start-up circuit 15 enables the blocking generator to start after the voltage between the busbars 13 and 16 rises above the voltage threshold of this circuit, which should be higher than the operating voltage on the lamp. After the lamp is ignited, the voltage on it in the start-up mode decreases to 15-20 V, the start-up current, which is approximately an order of magnitude higher than the operating current, leads to a decrease in the voltage at the output of the secondary power supply 3 with a falling current-voltage characteristic and the voltage between power supply buses 13 and 16 are reduced, falling below the second threshold (off threshold) of the starting circuit. Under these conditions, the generation of the blocking generator is disrupted, since the ferromagnetic core of the autotransformer b is saturated with a large constant current of the lamp and the feedback conditions are violated, and also because the start circuit 15 enters the braking mode, stopping the supply of inrush current to the base of the transistor 5 and switching the base to the potential of the power bus 13 or connecting the base to a negative bias source (not shown in Fig.). After warming up the lamp and returning it to normal operation, the current through the autotransformer (windings 7 and 8) decreases, the voltage at the lamp and at the output of the secondary power supply 3 increases, but does not reach the second switching threshold of the starting circuit 15 and therefore eliminating the possibility of restarting the g-generator block. If in the initial stage of ignition the lamp burns unstably and the electric discharge at high current in

does not occur, the ignition device continues to generate high voltage pulses that maintain the current in the lamp and cause its electrodes to warm up, followed by the transition to

sustainable arc burning.

The protection circuit is designed to limit the pulse voltage at the transistor 5 and at the output of the ignition device 1 in the absence of a lamp or with a faulty lamp, i.e. in idle mode, This circuit absorbs the energy of the ignition pulses, if the lamp does not ignite, and limits the slew rate of the current on the power transistor after it is closed in

0 pulse generation mode.

Depending on the choice of parameters of the electric elements of the circuit of the device 1, it can provide either ignition of cold lamps or ignition of cold lamps and

5 instantly reloads hot, freshly turned off lamps.

When using the device to ignite only cold lamps, when the output voltage of the device can

0, for example, in the range of 2-3 kV, to prevent prolonged operation of the blocking generator (while the lamp cools down) and to prevent the generator from turning on again after the lamp goes out5 or turned off in the start circuit 15 introduced a switching element of a time delay device or a temperature sensor that controls the temperature of the lamp (in Fig. 2 - contacts 27).

0 One of the possible electric circuits of the starting circuit 15 with two voltage thresholds and contacts of the time delay relay 27 is shown in FIG. 2. The same figure shows one of the possible 5 variants of the electrical circuit of the protection circuit 17.

The trigger chain 15 can be assembled using a Schmidt trigger. In the embodiment of FIG. 2 simplified version in

0 sucking the starter circuit includes an electromagnetic relay 18 with contacts 19, 20 and 21, zener diodes 22 and 23 to stabilize the voltage on the relay coil 18, zener diode 24 days current limiting through the relay winding

5 at low voltages and resistors 25 for setting the threshold for switching on the blocking generator and 26 for adjusting the threshold for turning off the blocking generator, which are connected to the relay winding via the contacts 27 of the time delay device.

The start-up circuit 15 operates as follows: When the voltage at the input of the start-up circuit rises between the power lines 13 and 16, current flows through the elements 24,18,27,25, which increases with increasing voltage and reaches, for example, at a voltage of 90 In (if the operating voltage of the lamp is 65 V) the relay operation current, while contacts 20 and 21 open, contacts 20 and 19 are closed and through elements 24,18, 22, 23, 27, 26, 19, 20 and the base of transistor 5 starts additional current flows, which triggers the blocking generator. From this moment on, the relay 18 is kept switched on by currents flowing along the two above-mentioned circuits. After igniting the lamp and reducing the voltage between busbars 13 and 16 to about 15-20 V, the currents in both of these circuits decrease to a value lower than the holding current of relay 18, its contacts switch to the initial position, the base of the transistor is connected through contacts 20 and 21 with a negative bus or with an auxiliary negative bias bus, not shown in FIG. 2, the generation of the blocking generator is stopped and the excitation winding current of the relay 18 abruptly decreases, turning it into a stable off state due to a rupture of the current in the second circuit formed by a circuit of elements 24, 18, 27, 26, 19, 20 and 5). To re-operate the starter circuit, it is necessary that the voltage at its input rises to the turn-on threshold, however, in the presence of a burning working lamp with an operating voltage of 65 V, such operation cannot occur.

The contacts 27 of the time delay or thermal protection relay exclude the possibility of starting the blocking generator for some time after the lamp is turned off, until its bulb has cooled to the required temperature. However, these contacts in the circuit diagram 15 may not exist if, for example, two or more lamps are connected in parallel to the output of device 1, from which only one lamp will always be lit and operated, and one of the lamps with a cold bulb will always be, or, if the parameters of device 1 are designed to ignite a hot lamp; in the latter case, it is necessary to provide for the forced switching of the starting circuit to the off state, for example, using a separate button for starting the hot lamp, which, after igniting the lamp, disconnects the starting circuit from the power source or

leads the relay 18 to the position in which the contacts 20 and 21 are closed.

The protection circuit 17 (Fig. 2) contains elements that limit the slew rate — 5 or voltage on transistor 5 when it is closed: diode 28, capacitor 29, and resistor 30, which extend the front of the voltage pulse to several microseconds, lowering the power switched by the transistor0 nostrum, elements absorbing the energy of the pulse generated by the blocking generator in the idle mode of the ignition device: resistors 31, 32, diode 33, and capacitor 34, and elements limiting

5, the amplitude of the voltage pulses on transistor 5: damper diode 35 and diode 36. An exemplary protection circuit may be implemented in any other way, some of which are shown in FIG. 2 elements may be missing, for example diodes 35 and 36.

The lamp operating current, passing for a long time through the windings 7 and 8 of the autotransformer 6, heats them and this leads to

5 to a general decrease in the efficiency of the power supply and lamp ignition equipment. In order to reduce the current through the autotransformer during the start-up mode of the lamp in the circuit of the proposed ignition device having

0 operating current and ignition pulses in one direction, it is possible to bypass windings 7 and 8 with a chain of elements with low active resistance. e.g. connected in series

5 by a resistor 37 and diodes or a diode assembly 38, while in series with the windings 7 and 8, a diode 39 and a capacitor 40 connected in parallel should be connected. The circuit of such a blocking generator with shunt elements 37, 38 and additional elements 39 and 40 is shown in FIG. , 3, works as follows. During the open state of the transistor 5 at the output end

5 of winding 8, a negative voltage pulse is generated under which a capacitor 40 is charged through a chain of elements 37, 38. During the generation of a positive-polarity pulse at the output end of winding 8, the voltage of capacitor 40 is added to the voltage of winding 8 and applied to the lamp 2. After the breakdown of the discharge gap of the lamp from the secondary source

5 of the power supply 3 with a filtering capacitor at the output, a current pulse flows, limited by the resistance of the windings 7 and 8, taking into account the voltage drop on the lamp and on the diode 39. At the same time, this current pulse passes a pulse through a circuit consisting of elements 37 and 38. After discharge In order to filter the filter capacitor at the output of the source 3, the lamp start-up current is established, which partially passes through the windings 7 and 8 and the diode 39, and partially through the elements 37 and 38. This reduces the heating of the windings during the lamp start-up mode. By the time the lamp is warming up, its current decreases several times and the active losses in the elements of the device 1 decrease, however, it is possible to further reduce the active losses in the device 1, if, in parallel to the resistor 37, turn on the resistor 41 with a small active resistance through contacts 42 and 43 relay (not shown in Fig. 3). A resistor 41 having a very low resistance in operating mode shunts the windings 7 and 8 of the autotransformer 6 and the resistor 37. and so on. a virtually ballast-free lamp supply from a secondary power source with a falling current-voltage characteristic or with a stabilized output current is realized.

Instead of contacts 43 and 44 and an electromagnetic relay, a semiconductor switch can be used in the device circuit.

The proposed device provides reliable ignition of short-arc MGLs with a relatively low voltage of the power supply and the goal is achieved - the electrical circuit of the ignition device is simplified, the efficiency of the device is increased and the ignition process is automated.

As an example, the table shows the electrical parameters of the ignition device for a 175 W short-arc metal halide lamp, powered by a secondary voltage source with a falling current-voltage characteristic.

The ignition device, assembled using the elements indicated in the table, when operating with an MGL at a power of 150 W, provides ignition pulses at a frequency of 2-3 kHz with a current of about 1 A and reliable instantaneous lamp ignition. In operating mode, the voltage drop on the device The ignition rate was 4.5 V, the power loss was 9 W, and the efficiency was the ratio of the output power to the input power. It was 94%.

The general technical effect is that such a device makes it possible to ignite the MGL at a supply voltage of the order of 100 V, while the available standard UIZUs only ignite the same lamps at a voltage of 220 V in the AC mains. High ignition efficiency combined with low energy loss in the ignition device and with automatic shutdown

generator after ignition of the lamp. FORMULA AND SECTION

Claims (2)

1. A device for igniting a short-arc metal halide high-pressure discharge lamp, comprising: a power source, a pulse generator, a transformer, the first terminal of the secondary winding of which is connected to the first terminal of the power source, and the second terminal to the first terminal for connecting the lamp; the second terminal for connecting the lamp is connected to the second terminal of the power source, the primary winding of the transformer is connected to the output of the pulse generator, characterized in that, for the purpose of To simplify, a threshold element with a hysteresis characteristic has been introduced into the device, the threshold for switching on the voltage of which is higher than the operating voltage of the lamp, and the threshold for switching off is higher than the initial voltage of the lamp in the starting mode after ignition, the input terminals of the threshold element are connected to the terminals of the power source, and the output the output is connected to the control input of the pulse generator, moreover, the power source is made with a falling current-voltage characteristic. 2. The device according to claim 1, with the proviso that a circuit from a parallel-connected diode and capacitor is connected, connected between the second terminal of the secondary winding of the transformer and the first terminal for connecting the lamp, and series-connected high voltage diode and ballast resistor, connected between the first terminal of the power source and the first terminal for connecting the lamp. The number of the element according to the scheme of FIG. 2 Item name main parameters 2 3 6 7 8 9 10 1.14 12 eighteen 2.24 23 25 26 28 29th thirty 31 32 33 34 35 36 Korotkougova MGL Secondary power supply Primary DC source Transistor 2T704A Auto transformer Winding Winding Winding Resistor Diode 2D202A Capacitor Electromagnetic relay RES49 Zener diode D814G Zener diode D814D Resistor Resistor Diode pole 2Ts103A Capacitor Resistor Resistor Resistor Diode2D213A Capacitor Diode 2D206V Diode2D202R Note. The numbers 1, 13, 15, 16, 17, 19, 20, 21, 27 on the diagram indicate parts or blocks whose parameters cannot be presented in the table. 175 W, 65-75 V output volt-ampere characteristic 27 V, current up to 10 A Wack up to 1000V 3 ek-up to 4 A winding wire 4 0.53 mm 75 vit. 108 vit. 6 vit. wire 0.25 4 ohms, 2 watts 2.2 uf Vpa6. 27 V Df stab 3-29 mA V stab. 11 V 3 stub, 3-24 mA, V stab FROM IN 9.1 kΩ, 0.5 W 7.5 kOhm. 0.5 watts 0.02 microfarads, 1500 V 10 kOhm. 5 W 240 Ohm, 5 W 7.2 kOhm, 5 W 0.012 uF, 1500 V League + 0-1. , L 1tsh Fig.Z I I w