Electric lamp and discharge devices: systems – Current and/or voltage regulation
Reexamination Certificate
2000-05-17
2001-02-06
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Current and/or voltage regulation
C315S20000A, C315S128000, C315S289000, C315SDIG005, C315SDIG007
Reexamination Certificate
active
06184635
ABSTRACT:
This application is closely related to the simultaneously submitted application with the internal file reference 99 P 5529.
TECHNICAL FIELD
The invention proceeds from a circuit arrangement for starting and for operating high-pressure lamps. Particularly at issue here are high-pressure and extra-high-pressure discharge lamps which are becoming increasingly widespread in all sectors of lighting engineering, because of their good luminous efficiency. Owing to their specific properties, they are mostly difficult to start and operate. This holds, in particular, for sodium high-pressure lamps with a relatively high xenon pressure. Because of their outstanding luminous efficiency, these lamps are particularly well suited for street lighting. In this case, they frequently replace existing systems with a substantially lower efficiency, for example mercury-vapor lamps. In addition, in this formulation of the problem, it is also necessary to solve the problem of power reduction (in conjunction with an identical luminous flux), the result of all this being a saving in energy.
PRIOR ART
DE-A 34 26 491 has already disclosed a circuit arrangement for starting and for operating high-pressure lamps, in which a series element is connected downstream of the dc output of the rectifier unit either directly or at most via a series element. The former series element contains an inductive filter in addition to the high-pressure discharge lamp. It is therefore possible to start lamps with a high cold filling pressure only with difficulty.
The problem of the difficult starting of high-pressure discharge lamps, in particular in the case of the sodium high-pressure lamps, has so far been solved in very different ways. More detail on this is to be found in the parallel application.
Specific starting aids have the disadvantage that they are not always adequate.
Very wide, high-energy starting pulses have the disadvantage of large, complicated and expensive starting inductors in the electronic ballast.
When providing increased transfer voltages with the aid of step-up converters, additional high-frequency transformers etc., the disadvantage occurs that this is technically complicated and cost intensive. Substantial losses occur in the components when there is a permanently applied high intermediate circuit voltage. Moreover, it is necessary to use overdimensioned components.
Starting gas mixtures have the disadvantage of worsening the lighting properties of the lamp.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a circuit arrangement as defined in the preamble of claim
1
which permits quick and simple starting of the high-pressure lamp, in particular in the case of systems without active harmonic filters.
This object is achieved by means of the characterizing features of claim
1
. Particularly advantageous refinements are to be found in the dependent claims.
Because of their high luminous efficiency, high-pressure and extremely high-pressure discharge lamps are spreading increasingly in all fields of lighting technology. Starting and operating them is, however, frequently problematical because of their specific properties. This holds, for example, in particular for sodium high-pressure lamps with very high xenon pressures (cold filling pressure above 1 atm, in particular in the case of approximately 2 atm). These lamps are particularly suitable for street lighting because of their outstanding luminous efficiency. In order to achieve a further energy saving (also in the ballast), electronic operation of these lamps is being increasingly targeted. However, circuit variants for the electronic ballasts which are technically very complicated and in part cost intensive are required to ensure the required parameters as regards starting voltage, transfer voltage, harmonic content etc. This holds, in particular, for starting these lamps.
The proposed circuit arrangement is suitable, in particular, for use for systems without additional active harmonic filtering. This is the case whenever only small charging capacitors or none at all, are used in the electronic circuit. It permits high-pressure lamps which would otherwise be very difficult to start to be started and transferred with the aid of an exceptionally low technical outlay.
According to the invention, the object is achieved by means of a circuit arrangement in which in order to transfer the discharge arc after completed break down, the lamp is provided with a transfer voltage which is higher than the customary no-load voltage. Lacking a substantial circuit outlay, the no-load voltage is normally the peak value of the line ac voltage. This increase is realized by raising, in particular doubling, the intermediate circuit voltage. After completed transfer of the lamp, the intermediate circuit voltage drops again to the normal value of the (rectified) line ac voltage.
The circuit arrangement differs from the customary designs in that it is technically very simple and thus can be implemented in an extremely cost effective way. It manages without the otherwise customary active components such as step-up converters, charging pumps etc., or additional high-frequency transformers. After a completed transfer, there are no longer any increased intermediate circuit voltages in the lamp operation, as a result of which the internal losses of the circuit are reduced.
REFERENCES:
patent: 4339695 (1982-07-01), Siglock
patent: 4392081 (1983-07-01), Brown et al.
patent: 4935672 (1990-06-01), Lammers et al.
patent: 4994716 (1991-02-01), Ganser et al.
patent: 5680015 (1997-10-01), Bernitz et al.
patent: 5739644 (1998-04-01), Bernitz et al.
patent: 5942883 (1999-08-01), Preis et al.
patent: 34 26 491 A1 (1985-02-01), None
Bessone Carlo S.
Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen MBH
Philogene Haissa
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