DE102007011245B4 - Supply unit for metal halide lamps - Google Patents

Abstract

Supply unit (1) for metal halide lamps (2), in particular high-pressure discharge lamps, for igniting and for supplying power to the metal halide lamps (2) from a network,
with a thermal switch (9) and a choke (10) for adjusting the lamp current to a desired value, arranged in series between a mains connection (3) and a lamp terminal (5), so that the mains voltage is substantially unimpeded on the non-ignited metal halide lamp (2) is present
with a monitoring device (18) which checks the supplied mains voltage at least before or during ignition for whether the mains voltage is within a specified voltage range and continues to monitor the mains voltage after the metal halide lamp (2) has been ignited,
with an ignition circuit (12) connected to or containing the monitoring device (18) and which is enabled for ignition pulse generation only when the voltage monitoring circuit (18) has determined that the mains voltage is within the specified voltage range,
with a short-circuit switch (22) connected in parallel with the metal halide lamp (2) or in series with the ...

Description

The The invention relates to an improved supply unit for metal halide lamps.

Metal halide lamps, In particular, high-pressure discharge lamps are often used with a series reactor at public Power supply operated. Together with an ignition circuit for generating Hochspannungszündimpulsen to ignite The still cold lamp gives a robust and reliable possibility for the operation of such lamps. However, errors can occur to an increase of the current and thus to an excessive excessive heating of the operating device in the form lead the choke can. In this case, the device must be switched off. This is usually a thermal switch, for example in Form of a bimetallic switch used by the operating current the metal halide lamp is heated.

During generic supply units, for example, the EP 1 528 577 A1 can be seen, goes to protect the supply unit usable thermal switch z. B. from the DE 102 58 281 A1 out. The thermal switch is integrated in a connection module there. The thermal switch is very compact. Overall, this allows the design of space-saving supply units.

Of the Thermal switch is triggered by various heat influences. First, it takes the ambient temperature at. On the other hand warmed up He himself according to the current flowing through him. He acts with it as a lazy overcurrent protection and switches off for larger overcurrents. For large overflows can However, it is the fast overheating of the thermal switch come to vaporizing contacts and training one Arcs lead can. This is to be ruled out because in such a case, the supply unit takes damage.

From the US 5 907 224 A It is known to monitor the input voltage at a supply unit for a metal halide lamp and to interrupt the power supply and thus also the Zündimpulsgenierung when the input voltage is outside of a specified range.

From that Based on the object of the invention, a supply unit to provide with thermal switch, despite possibly made Miniaturization safe operation or safe shutdown the supply unit allowed.

This object is achieved with the supply unit according to claim 1:
The supply unit according to the invention is suitable for metal vapor high-pressure lamps and also sodium vapor lamps. It has, in addition to the usual components on a monitoring device that checks the supplied mains voltage at least before the ignition of the lamp or even during the ignition of the same, whether the mains voltage is within a specified voltage range. If this is not the case, the generation of ignition pulses is suppressed at the ignition circuit.

The still cold lamp is first high impedance. By ignition pulses in the form of high voltage pulses, a gas discharge is initiated, so that a current flowing through the lamp heating the lamp to conditions comes. In a voltage target range, for example, of 180 Voltage goes up to 240 volts, put the case flowing through the lamp currents in one permissible Area. However, if there is a network error, such as a zero conductor error, before, it can cause overvoltages come, which reach up to 440 volts. The ignition of the discharge lamp leads in one to stream such a case, which leads to rapid overheating to lead can. The thermo-breaker responds, however, the high currents occurring can not always switch off safely. Arises at the thermal switch an arc, this may possibly persist for a long time and destroy the supply unit.

By the suppression of ignition pulses in the event of overvoltage this error condition is avoided. The monitoring device must to monitor, whether the mains voltage in a range of, for example, 0 volts to 240 volts lies. However, in the preferred case, firing pulses will occur not generated even if the mains voltage is a lower limit falls short of that larger than 0 is, for example, 180 volts. This will avoid the discharge lamp ignited at a mains voltage will that be for one safe operation of the lamp is not sufficient and soon to extinguish the Lamp would lead. If the lamp namely again and again goes off, runs They practically in continuous ignition operation and thus with an increased Wear. This too is prevented by the supply unit according to the invention.

The inventive supply unit has to limit the lamp current to a throttle. This throttle may have a tap for generating ignition pulses. The tap is then to the ignition circuit connected. Alternatively, a separate ignition transformer may be provided, which is connected in series with the throttle.

The monitoring device can be connected to a corresponding deactivation input of the ignition circuit be connected to disable this if an inadmissible mains voltage is detected. It is also possible, the monitoring device and the ignition device to merge into a circuit block by sending a signal indicating an inadmissible mains voltage internally of a circuit part containing the monitoring device forms, is given to a circuit part, which the ignition circuit forms.

Of the The above-mentioned thermal switch is connected in series with the throttle. The mains voltage is preferably at a from the point of view of the mains connection tapped in front of the thermal switch point and the monitoring device guided. Alternatively, the mains voltage can, however, also, at least as long the discharge lamp is not yet ignited, are tapped above the discharge lamp.

When Thermal switch is preferably a bimetallic switch in question. Preference is given to bimetal with Abschalthysteresis. Did he shut off, cools He turns off and can turn back on after some time. However, it stops the generation of ignition pulses as long as the inadmissible Mains voltage condition persists, so that the discharge lamp is not ignited but remains high-impedance and no current through the lamp or the throttle and the thermal switch can flow.

It is possible, to cancel the blocking as soon as the inadmissible mains voltage condition disappears. However, it is also possible, the monitoring circuit with a Memory, such as a flip-flop or other storage means to provide that stores and maintains the lockout state. The reset can, for example, by restarting a meantime switched off mains voltage. Alternatively it can be an external Intervention, for example by resetting of an EPROM.

at a simple embodiment becomes the mains voltage monitoring before and / or during of ignition carried out the lamp. According to the invention voltage monitoring always running and if there is an error condition, not just the generation prevented by ignition pulses but interrupted the flow of current through the gas discharge lamp. This can be done, for example, by a parallel to the gas discharge lamp lying switch is at least temporarily closed. In order to goes off the discharge lamp. If the switch is opened again, the discharge lamp would have to re-ignited but with the ignition pulse generation due to the present overvoltage condition is prevented. Thus, the supply unit switches in this Trap safely.

At Place a switch connected in parallel to the discharge lamp can with the discharge lamp also a semiconductor switch in series be switched, which is switched at least for a short time high impedance, when an overvoltage condition is detected and the lamp is thus turn off.

Further Details of advantageous embodiments will be apparent from the following description with the drawings and claims. The Description limited focus on essential aspects of the invention and other circumstances. The drawings give expert additional information, which is why hereby expressly is referred to the drawings.

In the drawings are in the 4 and 5 Embodiments of the invention illustrated. The 1 to 3 and 6 serve to illustrate the invention. Show it:

1 to 3 various embodiments of a supply unit in a schematic representation,

4 and 5 two embodiments of the supply unit according to the invention in a schematic representation and

6 a further embodiment of a supply unit in a schematic representation.

In 1 is a supply unit 1 illustrated, which serves to supply a high-pressure metal vapor lamp with electric power. The supply unit 1 according to 1 is at the same time ballast and ignitor. It is designed as 3- or 4-pole and has two network connections on the network side 3 . 4 on. These are connected to the electrical supply network, for example, an AC power supply with rated voltage 230 volts. On the lamp side, the supply unit has two lamp terminals 5 . 6 on, are connected to the leading to the metal vapor pressure lamp lines. The supply unit 1 has its own housing 7 on that in all 1 to 5 only symbolically indicated. In this housing is at least preferably a compensation capacitor 8th provided that the mains connections 3 . 4 connects with each other. In the embodiment according to 5 is the power connection 4 with the lamp connection 6 connected. Between the power connection 3 and the lamp connection 5 are a thermal switch 9 and a throttle 10 arranged in a row. The thermal switch 9 is normally closed. He opens when he passes through a longer limit current reaches an opening temperature. The thermal switch 9 is preferably designed as a bimetallic switch with switching hysteresis. For example, it can be housed in a terminal, as can be seen from the DE 102 58 281 A1 is known.

The throttle 10 serves at the circuit after 1 the current limit of the lamp current. It also serves to generate ignition pulses. For this she has a tap between her ends 11 on, to which an ignition circuit 12 connected. The ignition circuit 12 is in 1 exemplified in a simple variant. It includes two capacitors in this embodiment 13 . 14 which are connected in series. The capacitor 13 branches in front of the throttle 10 and leads over the capacitor 14 to a reference line 15 , in turn, with the mains connection 4 and the lamp connection 6 communicates. From the tap 11 carries a voltage-dependent switch, for example in the form of a DIAC 16 or a SIDAC to the connection point of the capacitors 13 . 14 , Exceeds the voltage on the capacitor 13 a limit will be the switch 16 low impedance and discharges the capacitor 13 over turns of the throttle 10 until its charge is used up and the switch becomes non-conductive again. This game repeats periodically to generate firing pulses.

The capacitors 13 . 14 is a switch 17 connected in series, which is normally closed. It serves to deactivate the ignition device 12 by a monitoring device 18 that with the switch 17 is in operative connection to open it as needed.

The monitoring device 18 is used to monitor the supply unit 1 applied operating voltage. For this purpose, it is via appropriate lines on the one hand to the mains connection 3 and on the other hand with the power connection 4 connected.

The supply unit described so far 1 works as follows:
Was the supply unit 1 de-energized for a long time is the metal vapor high-pressure lamp 2 cold and thus high impedance. Will now be operating voltage to the mains connections 3 . 4 applied, the mains voltage is substantially unchanged at the non-ignited metal vapor high-pressure lamp 2 at. Now the ignition device 12 active. A charging current flows to the capacitors 13 . 14 , Exceeds the voltage on the capacitor 13 while the breakdown voltage of the DIACS or switch 16 This discharges the capacitor 13 abruptly, causing the connection 11 a sudden change in current occurs. This will be by means of the throttle 10 generates in each power half-wave several Hochspannungszündimpulse, leading to a gas discharge in the metal halide lamp 2 to lead. Before and / or during this, the monitoring device checks 18 whether the mains voltage is in a range of admissibility, for example, 180 volts to 240 volts. If this is the case, the generation of ignition pulses is continued until the metal vapor high-pressure lamp 2 a current that becomes so large that the voltage at the terminal 11 for maintaining tilting vibrations in the capacitor through the 13 and the DIAC 16 formed tilting vibration generator is no longer sufficient. The metal halide lamp 2 goes into heat-up operation, where it draws increased current.

The heating operation leads to the heating of the metal vapor high-pressure lamp 2 until it goes into normal burning mode. It then draws rated current. If a lamp fault occurs, which leads to an increase in current, the thermal switch heats up 9 beyond its threshold and turns off. It is dimensioned so that it the operating current of the metal vapor high pressure lamp 2 can switch off without further notice.

Is trying the metal vapor high pressure lamp 2 to ignite when the mains voltage is outside the permissible range, the monitoring device prevents 18 the generation of ignition pulses. For example, a voltage of 400 volts to the power connections 3 . 4 created, detects the monitoring device 18 this immediately and opens the switch 17 , The ignition device 12 can not generate ignition pulses. Consequently, although the increased mains voltage of, for example, 400 volts to the metal vapor high pressure lamp 2 at. However, this is cold and non-conductive. Without ignition pulses, it can not carry any current. It thus does not come to a state in which too much current through the thermal switch 9 would flow from the thermal switch 9 can no longer be switched off.

At the circuit after 1 Many modifications are possible, which will be readily apparent to those skilled in the art. For example, the monitoring device 18 in place of the mains connection 3 also to the line between the thermoswitch 9 and the throttle 10 be connected. When switching on there is the same voltage as at the mains connection 3 at. So nothing essential changes in function.

Alternatively, the monitoring device 18 to the lamp connection 5 be connected. At the moment of switching on, the metal vapor high-pressure lamp is 2 high impedance, so that at the lamp terminal 5 also one of the mains voltage directly corresponding voltage is applied. However, the voltage monitoring then has to be on the period before the generation of ignition pulses remain limited.

2 illustrates a modified embodiment. As far as construction or functional equality with the above-described supply unit 1 is made regarding the structure and function of the functional unit 1a to 2 referred to the above description based on the same reference numerals. In contrast to the above-described surrounded supply unit 1 takes over the throttle 10 but not the function of generating ignition pulses. For this is a separate ignition transformer 19 intended. This is connected to a control circuit 20 connected to both the ignition device 12 as well as the monitoring device 18 contains. Regarding function and possible modifications is based on the description of the supply unit 1 directed.

3 illustrates a further modification of the supply unit 1a as a supply unit 1b , In addition to monitoring the mains voltage, the monitoring device takes over 18 here the monitoring of the switching state of the thermal switch 9 , This is the monitoring device 18 with both ends of the thermoswitch 9 connected. If he opens, a voltage drops over him from the monitoring device 18 is registered. It can now monitor the ignition pulses when re-closing the thermal switch 9 lock. This feature prevents a too-aged or otherwise damaged high-pressure metal vapor lamp 2 , which draws too large operating currents and thus for thermal shutdown of the thermal switch 9 leads, after the shutdown is ignited again.

The shutdown state may be in a memory module 21 be stored, for example in the form of a flip-flop or the like. The reset of the memory module 21 can be done for example by switching off and on the operating voltage. But it is also possible to make the reset of a manual intervention, such as a lamp replacement or a remote control signal or other measures.

The embodiments described above monitor the mains voltage in particular before and during the ignition. The following with reference to 4 described embodiment of the invention also allows the monitoring of the operating voltage and the timely shutdown of the supply unit 1c even if the operating voltage when ignited warm metal vapor high pressure lamp 2 runs out of the band of admissibility.

For this purpose, for example, starting from the supply unit 1b or also starting from the other supply units 1a or 1 , a switch 22 For example, in the form of a TRIACs provided parallel to the metal vapor high pressure lamp 2 is switched. His ignition electrode 23 is with the monitoring device 18 connected. Does this provide an overvoltage condition at the mains terminals 3 . 4 fixed, it prevents, as explained above, the generation of ignition pulses. Represents the overvoltage condition during normal operation of the high-pressure metal vapor lamp 2 fixed, it gives at least one preferably several ignition pulses to the switch 22 to at least one but preferably several half-waves of the voltage across the metal vapor high-pressure lamp 2 short-circuit. This extinguished by, the thermal switch 9 not yet responding to the brief overcurrent. Receives the switch 22 no firing pulses, it becomes high impedance. The extinguished metal vapor high pressure lamp 2 will not be re-ignited because the monitoring device 18 the ignition device 12 now locks.

Another embodiment of the invention is provided by the supply unit 1d according to 5 educated. For the explanation thereof reference is made to the above description. The throttle 10 can, as exemplified in 1 ge shows, also assume ignition function. Just as well, as in the 2 . 3 and 4 illustrates a separate Zündübertrager be provided. In addition, a monitoring of the opening of the thermal switch 9 corresponding 3 or 4 respectively. But this function can also be dispensed with.

The supply unit 1d allowed, as the supply unit 1c , the monitoring of the mains voltage even during normal operation of the metal vapor high pressure lamp 2 , This is with a semiconductor switch 24 connected in series by the monitoring device 18 is at least briefly opened, if they have an overvoltage condition in the supply network after the ignition of the metal vapor high-pressure lamp 2 finds. At the same time, in turn, the generation of ignition pulses is suppressed. Is the metal vapor high pressure lamp 2 not yet ignited, can open the semiconductor switch 24 remain under.

6 illustrates in simplified form a supply unit 1e in which the switches 16 and 17 to a switch 25 in the form of an externally controlled switch, z. B. a TRIACs are united. This is on the one hand to ground and on the other hand via a series circuit of a capacitor 13 ' and a coil 26 with the connection 11 the throttle 10 connected. The gate of the TRIAC is connected to the ignition device. For generating lamp ignition pulses, this Zeiinrich Ignition pulses to the gate. The emission of ignition pulses is prevented when the monitoring device 18 as discussed above in connection with 1 to 5 described, an impermissible state. The advantage of this circuit is the absence of the separate switch 17 , Otherwise, the above description of the embodiments according to 1 to 5 corresponding.

For a supply unit of a metal vapor high-pressure lamp is proposed to relieve the existing temperature-dependent switching circuit breaker monitoring device 18 provide that monitors the mains voltage. The mains voltage assumes values at which the metal vapor high-pressure lamp 2 suffers (undervoltage) or carries currents from the temperature switch 9 can no longer be switched off safely, prevents the monitoring unit 18 the generation of ignition pulses, ie it locks the ignition device 12 ,

1

supply unit

2

Halide high-pressure lamp

3

mains connection

4

mains connection

5

lamp connection

6

lamp connection

7

casing

8th

compensation capacitor

9

thermal switch

10

throttle

11

connection

12

ignition device

13

capacitor

14

capacitor

15

reference line

16

switch

17

switch

18

monitoring device

19

ignition transformer

20

control circuit

21

memory module

22

switch

23

ignition electrode

24

Semiconductor switches

25

switch

26

Kitchen sink

Claims (6)

Supply unit ( 1 ) for metal halide lamps ( 2 ), in particular high-pressure discharge lamps, for igniting and for supplying power to the metal halide lamps ( 2 ) from a network, with a thermal switch ( 9 ) and a throttle ( 10 ) for adjusting the lamp current to a desired value which is between a mains connection ( 3 ) and a lamp connection ( 5 ) are arranged in series, so that the mains voltage substantially unabated at the non-ignited metal halide lamp ( 2 ), with a monitoring device ( 18 ), which checks the supplied mains voltage at least before or during ignition, whether the mains voltage is within a specified voltage range and the mains voltage after the ignition of the metal halide lamp ( 2 ) is further monitored, with an ignition circuit ( 12 ) connected to the monitoring device ( 18 ) is connected or contains and that is only released for Zündimpulsgenierung when the voltage monitoring circuit ( 18 ) has determined that the mains voltage is in the specified voltage range, with a parallel to the metal halide lamp ( 2 ) short-circuited switch ( 22 ) or in series with the metal halide lamp ( 2 ) switched semiconductor switch ( 24 ), the monitoring device ( 18 ) after ignition of the metal halide lamp ( 2 ) in the presence of a fault condition the current flow through the metal halide lamp ( 2 ) is interrupted by the fact that the short circuit switch ( 2 ) closed at least for a short time or the semiconductor switch ( 24 ) is switched to high resistance for at least a short time, so that the metal halide lamp ( 2 ) goes out. Supply unit according to Claim 1, characterized in that it comprises one of a mains input ( 3 . 4 ) to the lamp ( 2 ) leading current path, in which the ignition circuit ( 10 . 12 . 19 ) is arranged. Supply unit according to claim 1, characterized in that the thermal switch ( 9 ) is a bimetal switch. Supply unit according to claim 1, characterized in that the monitoring device ( 18 ) in addition to its function of mains voltage monitoring the thermal switch ( 9 ) and blocks the generation of firing pulses if it had opened at least once. Supply unit according to Claim 4, characterized that the blockage until the next Restarting the operating voltage is maintained. Supply unit according to claim 4, characterized in that the blocking until the next reset of an EPROM of the ignition circuit ( 12 ) is maintained.