EP1296541A1 - Circuit device and method to produce UV rays - Google Patents

Abstract

The arrangement has a mains rectifier (3) with an intermediate circuit capacitor (5) in parallel with the d.c. output, a power unit with a static inverter (7) operated at a first frequency and a further second static inverter (10a,10b) per load (2a,2b), each with 2 power switches operated alternately with a second defined frequency. The loads are connected between the junctions of the power switches in the first and associated static inverters. Independent claims are also included for the following: an arrangement for outputting ultraviolet rays, especially for polymerizing ink in a printer, and a method of operating an inventive circuit arrangement.

Description

The invention relates to a circuit arrangement, a device for the emission of UV rays and a method of operation a circuit arrangement with the features of the preamble of independent claims.

For the operation of electrical consumers such as gas discharge lamps, for example, high pressure gas discharge lamps for generation ballasts are used for ultraviolet light. ballasts are used to flow through the gas discharge lamp limit so that there is a stable working point can adjust. At the same time with the ballast an alternating current for operation independent of the mains frequency of the gas discharge lamp. The ballast also serves the mains voltage for operating the gas discharge lamp Up enforce.

Electronic ballasts are already known, in which the alternating current for operating the gas discharge lamp with Generated inverters with electronic circuit breakers becomes. Such a device is for example in DE 42 38 388 shown. A DC-powered bridge resonance converter with controllable electronic switches is used to to control the primary circuit of a high-voltage transformer, in whose secondary circuit is a source of UV radiation.

EP 253 224 shows a circuit arrangement for high-frequency operation several low-pressure gas discharge lamps connected in parallel.

EP 698 310 includes a high-frequency AC converter Power factor correction for operating electrical discharge lamps known. In particular, this shows a power factor correction circuit (PFC) to use a high power factor to obtain. These various known devices but they all have certain disadvantages.

The simultaneous operation of several gas discharge lamps with a ballast is often not possible. The dimensions the known ballasts are also proportional large, so that problems arise during their installation, for example in printing devices where UV light for curing Printing inks is used. Such a device is in WO 98/54525.

It is an object of the present invention to address the disadvantages to avoid the known, in particular a circuit arrangement to create the economically producible and operable is whose dimensions are relatively small and which if necessary, the parallel operation of several electrical Allowed consumers. At the same time, the circuit arrangement the operation of consumers with relatively high performance enable. Another object of the present invention is to create a circuit arrangement that the Ignition of gas discharge lamps allowed without additional Ignitors are necessary.

According to the invention, these tasks are carried out with the features of characterizing part of the independent claims solved.

The circuit arrangement according to the invention is used for control from at least one electrical consumer with one AC. The electrical consumer is supposed to use an alternating current operated with a first, predetermined frequency become. In particular, the electrical consumer is a UV gas discharge lamp. The circuit arrangement is especially for designed for use in industrial areas. For example, it will for the operation of UV lamps in the power range of over 5 kW used.

The circuit arrangement has a device for generating a DC current. Typically the direct current is from rectified in a 3-phase three-phase network. The device can be used as a (passive) line rectifier or as an (active) converter be trained. The latter serves one in particular if possible sinusoidal mains current consumption. Here and below are understood as line rectifiers passive and active converters. Parallel to the DC output of the line rectifier an intermediate circuit capacitor is arranged. The intermediate circuit capacitor equals fluctuations in supply, that is, the Network power and demand, that means the lamp power.

The circuit arrangement also has a power unit with a first inverter. The first inverter is equipped with two electronic circuit breakers, which alternately switchable with the predetermined first frequency are.

The switching arrangement also has one for each electrical consumer one additional, second inverter each. Every second In any case, inverter with two electronic circuit breakers Mistake. The electronic circuit breakers of the second inverters are predeterminable with a second Frequency can be switched alternately. The second predeterminable frequency is preferably a high frequency, in particular a frequency in the range between 20 and 50 kHz.

Each electrical consumer is connected to the center tap between the circuit breakers of the first inverter connected. The second connection of every electrical consumer is with the center tap between the circuit breakers one of the second inverters is connected. The first and the second inverter are each with the DC output connected to the mains rectifier.

With the switching arrangement according to the invention, it is possible to have several electrical consumers simultaneously with a circuit arrangement to operate. Thereby for the operation of N consumers only 2 + 2N electronic circuit breakers required. The cost and dimension of the circuit arrangement can therefore be reduced become. The circuit breakers that can be switched at the first frequency the first inverter are used to operate the electrical consumers with the predetermined first frequency. The circuit breakers of the second inverter are thereby advantageously at a high frequency, typically 20 to 50 kHz operated, while the electrical consumer typically can be operated at about 250 Hz. With the second inverter can the current and thus the pulse width modulation Power controlled individually in each individual consumer become.

According to an alternative embodiment of the invention the circuit arrangement is used to control at least two electrical consumers. Thereby with the center tap between the circuit breakers of the first inverter in parallel at least two electrical consumers connected to each other. Through this parallel connection, the number of required electronic switch for the operation of several electrical Be reduced to consumers. A combination of a parallel connection from several electrical consumers using the center tap between the circuit breakers of the first Inverter and one second inverter per electrical However, consumers as described above are preferred.

According to a further preferred exemplary embodiment, the Line rectifier to correct the power factor, i.e. as PEC trained. With a rectifier designed as a PFC the voltage with which the electrical consumer can be operated. This also allows Operate lamps with higher burning voltage. Thanks to the PFC follows in addition, the mains current consumed is always sinusoidal Line voltage curve. This can at best be complied with Standards are observed.

According to a further preferred exemplary embodiment, the or the second inverters are operated in such a way that their Center tap between the circuit breakers a pulse width Modulation is performed. This allows the current and so that the performance of each individual consumer can be regulated separately. The pulse width modulation is carried out by an external control loop set.

The circuit arrangement is preferred according to another Embodiment designed as a resonant output stage. By suitable measures, e.g. through additional resonance circuits that Switching losses can be assigned to the circuit breakers prevent. A resonant output stage therefore allows operation the device with a high switching frequency.

The intermediate circuit is also advantageous with film capacitors built up. This also enables lower losses to be achieved. In addition, there is a higher surge resistance and a longer lifespan.

According to yet another embodiment in which the electrical Consumer is designed as a gas discharge lamp between the gas discharge lamp and the first inverter each arranged a resonance circuit. The first inverter is for Ignition of the gas discharge lamp can be operated at a frequency that corresponds to the resonance frequency of the resonance circuit. Through excessive resonance results from the center tap between the circuit breakers high voltage of the first inverter, which is sufficient to ignite the gas discharge lamp. The inventive Device therefore allows, only by suitable Activation to ignite the lamp without a separate ignitor.

In a typical embodiment, the power unit is designed as an inverter ignition unit. The power unit has six circuit breakers, which together form a first and form two second inverters. On the output side are the Provide inverter with four chokes and capacitors. there form the two connected to the first inverter Chokes with connected capacitors the resonance circuit. This arrangement is used to operate two electrical consumers, typically gas discharge lamps. More chokes and Capacitors are connected to the second inverter. she serve the high frequency of the second inverter from the Keep the lamp away.

According to a further preferred exemplary embodiment, the Circuit arrangement modular. The line rectifier and the power unit are interconnectable and mutually exclusive separable modules. The modules are identical Power modules designed, wherein a first power module the PFC and a second power module the inverter ignition unit to operate e.g. forms two consumers.

The output power of the circuit arrangement is for each lamp individually adjustable.

According to the present invention, it is also conceivable to have two to connect electrical consumers in series. This will be particularly with the use of a PFC that allows a higher DC link voltage and thus also a higher lamp voltage allowed.

The circuit arrangement according to the invention is advantageously used operated a microcontroller. This makes operation flexible the device with desired parameters possible. At the same time, the circuit arrangement with inputs and outputs Mistake. The inputs allow the coupling of control or control signals, for example measured values of those from the gas discharge lamp power delivered. The outputs allow the Output / display of operating parameters of the circuit arrangement, for example the one consumed by electrical consumers Power.

The circuit arrangement described above is advantageous in a device for emitting UV rays, for example used to polymerize printing inks in a printing press. For example, the device can be as in WO 98/54525 shown, used. This device has at least one, preferably two UV high-pressure gas discharge lamps and one Ballast with a circuit arrangement as described above on. The second inverter is connected to a High compared to the first frequency of the first inverter Frequency operated. Typically the second frequency is with which the second inverter is operated, about 20 to 50 kHz, while the first frequency on which the first Inverter is operated, typically 250 Hz. For generating an ignition pulse when operating a gas discharge lamp the first inverter is operated at a frequency that of the resonance frequency of the between the first inverter and the resonant circuit switched to the electrical consumer equivalent.

The use of the circuit arrangement according to the invention for Drying or polymerizing printing inks leads to special ones Benefits. In particular, despite limited space several UV lamps are operated. The fast control loops allow optimal intermittent operation with high performance when needed and low idle power, so that the heat generated can be reduced. The device has also especially in connection with such printing machines following advantages. Through the electronic ballast the lamp current can be set to the setpoint very quickly, within millisecond fractions. This allows using very short cycles. Changes in lamp wattage in the millisecond range are easily possible.

According to the invention, suitable filters are also provided, that prevent the emission of high-frequency components or reduce.

Figur 1:

eine schematische Darstellung einer erfindungsgemässen Vorrichtung zur Abgabe von UV-Strahlen,

Figur 2:

eine schematische Darstellung einer erfindungsgemässen Schaltungsanordnung,

Figur 3:

eine vergrösserte Darstellung eines Leistungsschalters der erfindungsgemässen Schaltungsanordnung,

Figur 4:

eine schematische Darstellung eines ersten alternativen Ausführungsbeispiels der Schaltungsanordnung,

Figur 5:

eine schematische Darstellung eines zweiten alternativen Ausführungsbeispiels der erfindungsgemässen Schaltungsanordnung,

Figur 6:

Darstellung von Spannungs- und Stromverlauf beim Betrieb der Schaltungsanordnung gemäss Figur 2 und

Figur 7:

detailliertere Darstellung der Schaltungsanordnung gemäss Figur 2 in einer erfindungsgemässen Vorrichtung.

The invention is explained in more detail below in exemplary embodiments and with reference to the drawings. Show it:

Figure 1:

1 shows a schematic representation of a device according to the invention for emitting UV rays,

Figure 2:

1 shows a schematic representation of a circuit arrangement according to the invention,

Figure 3:

2 shows an enlarged view of a circuit breaker of the circuit arrangement according to the invention,

Figure 4:

1 shows a schematic illustration of a first alternative exemplary embodiment of the circuit arrangement,

Figure 5:

2 shows a schematic representation of a second alternative exemplary embodiment of the circuit arrangement according to the invention,

Figure 6:

Representation of voltage and current curve during operation of the circuit arrangement according to FIGS. 2 and

Figure 7:

Detailed representation of the circuit arrangement according to Figure 2 in a device according to the invention.

FIG. 1 shows a device 18 for emitting UV radiation. The device 18 has a ballast 19, which for Operation of two high pressure gas discharge lamps 2a, 2b is used. The Ballast 19 contains a circuit arrangement 1. The circuit arrangement 1 has a line rectifier 3. With the Mains rectifier 3 can be a 3-phase alternating current of a three-phase network 20, for example 3 x 400 volts, rectified and increased to a higher voltage, for example 750 volts DC become. The circuit arrangement 1 is also with an intermediate circuit capacitor 5 provided that compensates for fluctuations. A power unit 6 is provided with the intermediate circuit capacitor 5 connected, which one according to the required lamp power constant, independent of the mains voltage, typically supplies a rectangular alternating current. The device 18 can be operated via a microcontroller 21, which via a Electrical isolation 22 connected to the circuit arrangement 1 is. The microcontroller 21 has inputs 23 and outputs 24 provided. The inputs 23 serve for the input of control signals, the outputs 24 for output of operating values Device 19, for example that of the lamps 2a, 2b Power. The inputs can, for example, be regulated Operation of the device 19 with a predetermined output Lamp power can be used.

In Figure 2 is the circuit arrangement 1 of a first embodiment shown schematically. The line rectifier 3 is designed as a bridge rectifier from the three-phase network 20 is supplied. Parallel to the DC outputs 4a, 4b of the rectifier 3, the intermediate circuit capacitor 5 is connected. A first inverter 7 with two circuit breakers 8a, 8b is also connected to the DC outputs 4a, 4b. The first inverter 7 is in operation of the circuit arrangement 1 operated a first frequency f1 of 250 Hz, so that the circuit breakers 8a, 8b in the center tap 9 between the Circuit breakers 8a, 8b have a square-wave alternating current of 250 Hz produce. With the center tap 9 are parallel to each other two lamps 2a, 2b connected. Between the center tap 9 and a resonance circuit 12 is arranged for each of the lamps 2a, 2b each consist of a resonance choke 14a or 14b and a resonance capacitor 16a or 16b composed. The resonance circles 12 serve to generate a resonance peak for igniting the Gas discharge lamps 2a, 2b by switching the inverter 7 with a frequency f3, which is the resonance frequency of the resonance circuit 12 corresponds.

Two second inverters 10a, 10b are also connected to the DC outputs 4a, 4b of the mains rectifier 3 connected. The second inverters 10a, 10b are also each with two Circuit breakers 11a, 11b and 11c, 11d provided. The second The gas discharge lamp 2a, 2b is connected via a filter choke 13a or 13b with the center tap 27 each of the inverters 10a, 10b connected. The output of the gas discharge lamps 2a, 2b is also via a filter capacitor 15a, or 15b with the negative DC output 4b of the mains rectifier 3 provided.

During the electronic circuit breaker 8a, 8b during operation the device is operated at a first frequency f1, which is relatively low, typically 250 Hz the circuit breakers 11a, 11b, 11c, 11d of the second inverter 10a, 10b operated on a second frequency f2, the is relatively large, typically in the range between 20 and 50 kHz. The electronic circuit breakers 11a, 11b on the one hand and 11c, 11d, on the other hand, lead to the center tap 27 a pulse width modulation so that the current in the filter chokes 13a, 13b oscillates around a predetermined value. The regulation of electricity through the consumer typically takes place via a microcontroller that controls the switching times of the electronic Switch 11a, 11b, 11c, 11d controls. Also an analog regulation is conceivable.

Figure 3 shows the structure of the only schematically shown in Figure 2 Circuit breaker. The circuit breakers are called IGBT designed with an integrated diode. Typically, circuit breakers of the manufacturer International Rectifier, type IRG4PSH71KD used.

Filterdrosseln 13a, 13b: je 500 H

Resonanzdrossel 14a, 14b: je 500 H

Filterkondensator 15a, 15b: 13.6 F

Resonanzkondensator 16a, 16b: 88nF

Zwischenkreiskondensator 5: 40 F

Gasentladungslampe: z.B. Mitteldruck Quecksilberdampflampe oder Hochdruck-Gasentladungslampe herkömmlicher Bauart.

f3: 24 kHz

The components described above are dimensioned in the exemplary embodiment as follows:

Filter chokes 13a, 13b: 500 H each

Resonance choke 14a, 14b: 500 H each

Filter capacitor 15a, 15b: 13.6 F

Resonance capacitor 16a, 16b: 88nF

DC link capacitor 5: 40 F

Gas discharge lamp: eg medium pressure mercury vapor lamp or high pressure gas discharge lamp of conventional design.

f3: 24 kHz

In Figure 4 is an alternative embodiment of the circuit arrangement shown. The same reference symbols denote the same Components. In contrast to the exemplary embodiment according to FIG. 2 4, however, the exemplary embodiment is only with a gas discharge lamp 2a operated, so that only a second inverter 10a is necessary.

Figure 5 shows a further alternative embodiment. According to Figure 5, the line rectifier 3 is designed as a PFC. The mains rectifier 3 is provided with six circuit breakers 17. The circuit breakers 17 are controlled so that the 3-phase alternating current received via chokes 28 sinusoidal is. At the same time, the DC link voltage can exceed the peak value the mains AC voltage can be increased. Especially A line rectifier designed as a PFC can advantageously be used 3 as shown in Figure 5 in combination with the power unit Insert 6 according to Figure 2. The mains rectifier 3 and the power unit 6 can be identical modules with each 6 electronic rating cards. Figure 5 shows two electrical consumers connected in series 2a, 2c. An operation of series connected to each other Consumers are possible thanks to the PFC, which is designed for a higher output voltage provides.

Figure 6 shows the current or voltage curve at different Points of the circuit arrangement according to FIG. 2.

In the top curve one, the voltage UB1 is at the center tap 27 between the circuit breakers 11a, 11b and 11c, 11d of the second inverter 10a and 10b shown. In the second illustration is the current I1 through the filter choke 13a or 13b shown. In the third representation, the voltage is U1F shown above the filter capacitors 15a, 15b. The fourth representation shows the voltage UB2 between center tap 9 between the electronic circuit breakers 8a, 8b of the first Inverter 7 and the negative DC connector 4b. The fifth representation shows, compared to the previous representations on a smaller scale, the voltage UlR across the resonance capacitors 16a, 16b.

To ignite the gas discharge lamps, the inverter 7, that is to say its circuit breaker 8a, 8b, is briefly operated at a high frequency f3 of approximately 24 kHz, which corresponds to the frequency of the resonance circuit 12 with the resonance choke 14a, 14b and resonance capacitor 16a, 16b. The circuit breakers generate short bursts of 500 volts (see voltage UB2). This results in a final voltage of up to 4 kV due to excessive resonance at the input of consumers 2a, 2b (see fifth illustration). In the first period of 2 milliseconds, as shown in FIG. 6, the excessive resonance has not yet led to the lamps 2a, 2b being ignited. Therefore, in the second period (2 to 4 to milliseconds), the inverter 7 continues to be operated at the high frequency f3, so that an ignition voltage is generated in the resonant circuits 12 by increasing the resonance. The high voltages lead to ignition in at least one of the lamps 2a, 2b. As soon as all lamps have ignited, the lamps can be operated normally. Such bursts only have to be generated until all electrical consumers have ignited. The lamps 2a, 2b are decoupled from one another due to the chokes 14a, 14b. The ignition resonant circuit 12 is excited with each switching process and can deliver high voltage peaks if the lamps 2a, 2b are not already on.
After the ignition, the electronic switches of the first inverter 7 are switched at the predetermined frequency f1 with which the lamps 2a, 2b are to be operated. According to the fourth illustration in FIG. 6, the voltage UB2 is a rectangular AC voltage.

As long as no ignition has taken place, the lamp 2a, 2b flowing current I1 essentially zero. After the ignition the amount of current I1 oscillates through lamp 2a, 2b by one predetermined value. The direction of the current depends on the circuit the switch 8a, 8b of the first inverter 7. At the time the switch 8a is closed between 2 and 4 msec the lamp current is negative i.e. it flows from the positive DC connection 4a via the switch 8a through the resonance chokes 14a or 14b backwards through the lamp 2a or 2b to Center tap 27 between the switches 11a, 11b of the second Inverter 10a or between the switches 11c, 11d of the second inverter 10b. The current flows when closed Switches 11b and 11d to the negative direct current connection 4b, whereby the amount of electricity increases. If the switch 11b open and the switch 11a is closed, the current drops again from. By selecting the switching times specifically, the Regulate the current to the desired value. Since the switching frequency of the second inverter 10a, 10b compared to the switching frequency of the first inverter 7 is high, is the value of the current I1 relatively stable and oscillates around the specified value. A synchronization of the frequency f1 of the first inverter 7 and the frequency f2 of the second inverter 10a, 10b not mandatory.

The voltage UB1 at the center tap 27 (see top illustration in Figure 6) oscillates with the frequency f2 between 0 V and one Maximum value of 500 V with a rectangular shape. The switches 11a, 11b and 11c, 11d are operated with pulse width modulation in such a way that the lamp current corresponds to the setpoint.

At the point in time between 4 and 6 ms, switch 8b is closed, while the switch 8a is opened. The power is on therefore from the center tap 27 through the lamps 2a and 2b, then through the resonance chokes 14a, 14b and via the circuit breaker 8b to the negative direct current connection 4b.

The entire ballast 19 is shown in more detail in FIG. The ballast 19 has a mains input part 25 with appropriate fuses that ensure safe operation allow the ballast 19. Fuses for overcurrent protection, PTC resistors for inrush current limitation and on Surge arresters are part of the network input 25.

A line filter 26 is connected downstream of the line input 25 to reduce symmetrical and asymmetrical interference.

The output of the line filter 26 is in the power factor corrector trained line rectifier 3 passed.

The line rectifier 3 and the line rectifier 3 connected downstream Power unit 6 are schematic as in Figure 2 shown as identical modules. In addition, is a Output filter 29 from chokes 30 and capacitors 31 for reduction provided by radiation.

The output filter 29 is connected to the two gas discharge lamps 2a, 2b connected. The current consumed by the lamps 2a, 2b measured with current sensors 32. The measured current values serve to regulate the current. You will be in the inputs 23 of the Microcontrollers 21 entered. Other current sensors 33 are used for measuring the current consumption of the mains rectifier 3 and Regulation of the mains rectifier designed as a PFC 3.

The current through the lamps 2a, 2b becomes individual with the current sensors measured. The lamp current and thus the lamp power can therefore be individually regulated to a setpoint. to Regulation serves the microcontroller, which is the circuit breaker controls.

Conventional UV gas discharge lamps are typically used. The ballast 19 allows the lamps with a Operate power of up to two times 10 Kw.

It is also conceivable with the circuit arrangement more than two to operate electrical consumers in parallel. To a further second inverter is provided and each Consumer is using the center tap between the electronic Circuit breakers of the first inverter on the one hand and each with the center tap between the switches one of the second inverter connected.

Claims (16)

Circuit arrangement (1) for controlling at least one electrical consumer (2a, 2b) with an alternating current with a first predeterminable frequency (f1), in particular for a high-pressure gas discharge lamp
a mains rectifier (3) with an intermediate circuit capacitor (5) connected in parallel to the direct current output (4a, 4b)
and with a power unit (6) for generating the alternating current with a first inverter (7) with two electronic power switches (8a, 8b) which can be switched alternately with the first predeterminable frequency (f1), one power switch (8a, 8b) each is each connected to a DC voltage output (4a, 4b) of the mains rectifier (3),
characterized in that the switching arrangement (1) for each electrical consumer (2a, 2b) has a further, second inverter (10a, 10b) each with two electronic power switches (11a, 11b, 11c, 11d), which alternate with a second predeterminable one Frequency (f2) can be switched, one power switch (11a, 11b, 11c, 11d) each of the second inverters being connected to a direct current output (4a, 4b) of the mains rectifier (3),
Each electrical consumer (2a, 2b) is connected on the one hand to the center tap (9) between the circuit breakers (8a, 8b) of the first inverter (7) and on the other hand one electrical consumer (2a, 2b) is connected to the center tap (27) one of the second inverters (10a, 10b) is connected between the circuit breakers (11a, 11b, 11c, 11d). Circuit arrangement, in particular according to claim 1, for controlling at least two electronic consumers (2a, 2b) with an alternating current with a first predeterminable frequency (f1), in particular for a high-pressure gas discharge lamp,
with a mains rectifier (3) with an intermediate capacitor (5) connected in parallel to the direct current output (4a, 4b)
and with a power unit (6) for generating the alternating current with a first inverter (7) with two electronic power switches (8a, 8b) which can be switched alternately with a first predeterminable frequency (f1),
characterized in that a power switch (8a, 8b) is connected to a direct current output (4a, 4b) of the mains rectifier (3)
and that at least two electrical consumers (2a, 2b) connected in parallel to one another are connected to the center tap (9) between the circuit breakers (8a, 8b). Circuit arrangement according to one of claims 1 or 2, characterized in that the mains rectifier (3) is designed as a PFC. Circuit arrangement according to one of claims 1 to 3, characterized in that the second inverter or inverters (10a, 10b) are modulated pulse widths. Circuit arrangement according to one of claims 1 to 4, characterized in that the inverters (7, 10a, 10b) are designed as a resonant output stage. Circuit arrangement according to one of claims 1 to 5, characterized in that the intermediate circuit capacitor (5) is designed as a film capacitor. Circuit arrangement according to one of claims 1 to 6, characterized in that between the one or more electrical consumers designed as a gas discharge lamp (2a, 2b) and the center tap (9) of the first inverter (7) a resonance circuit (12) is arranged and that first inverter (7) for igniting the gas discharge lamps (2a, 2b) can be operated at a frequency (f3) which corresponds to the resonance frequency of the resonance circuit (12). Circuit arrangement according to claim 7, characterized in that the power unit (6) is designed as an inverter ignition unit with six power switches (8a, 8b; 11a, 11b, 11c, 11d), which has four chokes (13a, 13b, 14a, 14b) on the output side ) and capacitors (15a, 15b, 16a, 16b) is provided,
wherein the chokes (14a, 14b) connected to the center tap (9) of the first inverter (7) form the resonant circuit (12) with the connected capacitors (16a, 16b). Circuit arrangement according to one of Claims 1 to 8, characterized in that the mains rectifier (3) and the power unit (6) are designed as modules which can be connected to and separated from one another. Circuit arrangement according to Claim 9, characterized in that the power unit (6) and the line rectifier (3) are designed as identical power modules. Circuit arrangement according to one of claims 1 to 10, characterized in that the output power of the circuit arrangement is continuously adjustable / that the circuit arrangement can be switched currentless Circuit arrangement according to one of claims 3 to 11, characterized in that two electrical consumers (2a, 2c) connected in series are provided. Device (18) for emitting UV rays, in particular for polymerizing printing inks in a printing press, with at least one, preferably at least two UV high-pressure gas discharge lamps (2a, 2b, 2c),
with a ballast (19) which is provided with a circuit arrangement (1) according to one of claims 1 to 12. Device according to claim 13, characterized in that the device is provided with inputs (23) and / or outputs (24) for the input of control signals and / or for the output of measured values. Method for operating a circuit arrangement according to one of claims 1 to 13,
characterized in that the second inverter (10) is operated at a frequency (f2) in the range from 20 to 50 kHz and in that the first inverter (7) is operated at a frequency (f1) of approximately 250 Hz. Method according to Claim 14 for operating a gas discharge lamp, in particular a high-pressure gas discharge lamp,
characterized in that, in order to generate an ignition pulse, the first inverter (7) is operated at a frequency (f3) which corresponds to the resonance frequency of a resonance circuit (12) connected upstream of the consumer (2a, 2b).

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