WO2014172723A1

WO2014172723A1 - Converter module for operating illuminants, having a galvanically isolated clocked converter

Info

Publication number: WO2014172723A1
Application number: PCT/AT2014/000081
Authority: WO
Inventors: Markus Sandholzer
Original assignee: Tridonic Gmbh & Co Kg
Priority date: 2013-04-23
Filing date: 2014-04-18
Publication date: 2014-10-30
Also published as: DE102013207327A1; AT15875U1

Abstract

In one aspect, the invention relates to a converter module, having: a primary-side galvanically isolated converter clocked by means of a switch, wherein said converter can be supplied from the input side by an AC voltage, particularly a mains voltage, or a DC voltage, and originating from the secondary side thereof a load, preferably at least one illuminant, can be operated; and a control unit designed to control an on-time period of the switch in a feed-forward operation and/or by using a fed-back measurement signal. A constant or variable limitation of the on-time period of the switch can be provided for a defined period of time or a defined number of switching cycles after switching on the DC or AC voltage.

Description

Converter module for the operation of lamps, with potential-separating clocked converter

The invention relates to a converter module with clocked converter, in particular with a Flyback- andler (flyback converter, also high-buck converter), as e.g. used for the operation of light sources (LEDs, OLEDs, gas discharge lamps ...). In particular, the invention relates to the use of floating-type clocked converters in such a converter module, which are clocked by a clocked semiconductor switch configured as a transistor, preferably a FET transistor (e.g., MOSFET).

As a starting point for the invention can, for example. DE 10 2010 064 032 AI, the use of a flyback converter in a converter module. for gas discharge lamps. Furthermore, EP 0 470 750 A2 may be mentioned, in which the use of a flyback converter in a power supply unit is described.

The potential-separating clocked converter divides the converter module into a primary side and into a potential-separated secondary side. The converter module, a supply voltage / supply current is supplied on the primary side, the / in particular corresponds to the power supply or derived therefrom. Alternatively, a DC supply may be available. In particular, the supply voltage / supply current is a DC voltage / DC current or an AC voltage / AC current (DC or AC voltage / current). Starting from the secondary side of the converter module, a load, in particular at least one light source, is then supplied. Preferably, the converter module is arranged in a ballast, or is part of the ballast.

The isolated clocked converter of the converter module transmits a power from the primary side to the secondary side. With reference to FIG. 1, the basic mode of operation of a converter, as it is mainly considered below, will be briefly explained. When the switch is closed (Figure 1, top), a primary winding of the transducer is connected directly to the supply voltage / supply current, the primary current and magnetic flux into the converter increases and energy is stored in the converter Voltage is then negative so that a secondary side diode shuts off and a secondary side capacitance supplies energy to the load.

When the switch is opened (Figure 1, bottom), the primary side current and the magnetic flux will drop. The voltage induced on the secondary side is then positive, and the diode no longer locks, so that the current can flow out of the converter. The energy provided by the converter on the secondary side charges the capacity and supplies the load. To regulate the transmitted power, the converter module further has a control unit, which, for example, as a proportional controller (P-controller), proportional-integral controller (PI controller), proportional-integral-differential Controller (PID controller) and / or proportional-derivative controller (PD controller) may be formed. As a control unit, an integrated circuit (IC, ÄSIC) or a microcontroller can further be used. Thus, a load is operated on the converter module which is operated from the secondary side of the converter with power.

After switching on or resetting the supply voltage / supply current, the control unit of known converter modules will first attempt to regulate, as quickly as possible, during a starting phase, to a nominal value for the power output which is provided for the load. Thus, the on-time of the converter switch (FET, MOS FET, ...) is selected to be long enough to achieve high energy transfer across the converter.

However, this means that during this starting phase, a very high current flows through the transducer switch. This is partly due to the fact that capacity on the secondary side of the converter, but also for example. Chokes must first be charged and therefore there is a high power requirement on the secondary side.

This can lead to an avalanche effect / avalanche effect ("avalanche effect", "avalanching", avalanche multiplication or carrier multiplication) on the converter switch, which can damage or destroy the silicon structure of the converter switch, that is to say the semiconductor switch element the result can lead to failure of the switch and thus the converter module. As I said, this high current is caused by the fact that after switching on the supply voltage / the supply current, a very high current from the secondary side of the converter is first requested to bring the secondary side in a desired operating condition.

During an avalanche / avalanche effect, a large amount of energy is also converted into thermal energy. The aim of the invention is therefore to provide a solution that allows operation of the converter module and at the same time prevents damage or destruction of the converter switch, in particular by preventing it to avalanche effect / avalanche breakdown effect during the phase immediately after switching on the

Supply voltage / supply current comes.

The solution according to the invention is realized by an apparatus and a method as claimed in the independent claims. Further development of the invention is the subject of the dependent claims.

In one aspect, the invention provides a converter module, comprising: a potential-separated converter clocked on the primary side by means of a switch, which can be supplied on the input side from an AC voltage, in particular a mains voltage, or a DC voltage, and from the secondary side of which a load, preferably at least one light source is operable, a control unit adapted to maintain a duration of the switch in a feed forward mode and / or using a feedback To regulate the measuring signal. For a certain period of time or a certain number of switching cycles after the DC or AC voltage has been switched on, a constant or variable limitation of the switch-on time duration of the switch can be specified. "Restriction" means that the limited on-time is shorter than the one that can be set as the maximum _on- time ( _on- time) after the start-up phase The control may be a linear or ramp-up of the on-time.

The control unit may change the switch-on time period within the determined time period in equal or variable intervals.

The measuring signal may be a supplied parameter, in particular a feedback signal from the secondary side of the transducer,

5 € 5X, £ ^" 1 _*

The measurement signal may be a parameter that reflects the current / voltage at the load and / or a parameter that reflects the type of load connected. The specific time duration can be 2 to 12 ms, in particular 4 to 10 ms.

The control unit may increase the on-time by a fixed or variable value.

The control unit can increase the on-time by 1 ps every 1 ms. The control unit may determine the switch-on period on the basis of a stored function and / or a look-up table.

In a further aspect, the invention provides a ballast for lighting means, in particular for LEDs, with a converter module as described above.

The invention also provides a luminaire with a ballast as described above.

In a still further aspect, the invention provides a method for operating a converter module, wherein a control unit, a switch-on of a primary-clocked by a switch clocked potential-separated converter, the input side starting from an AC voltage, in particular a mains voltage, or a DC voltage can be supplied and on the basis of whose secondary side a load, preferably at least one light source can be operated, is regulated in a feed-forward mode and / or using a feedback measuring signal, and wherein for a certain period of time or a specific number of switching cycles after switching on the DC or AC voltage is a constant or variable limitation of the switch-on time of the switch is specified.

The invention will now be described with reference to the figures. Showing:

Schematically a basic structure of a

clocked isolated switch; Fig. 2 shows schematically a converter module according to the invention. In the present case, a switch-on means interrupting the supply voltage / supply current of the converter module, as occurs, for example, when restarting a ballast or reconnecting the mains voltage supply, but also restarting the load, ie the connected lighting means.

In Fig. 2, the converter module with K and the load is denoted by L. The dashed elements indicate an optional return of a parameter from the Lasst or a parameter identifying it, which may optionally, as well or alternatively as a parameter, be supplied from the secondary side of the converter to the control unit. The potential separation by the transducer is indicated in the converter by a dot-dash line. It will be understood that additional modules (e.g., in a ballast) may be connected between the mains supply and the converter module and / or between the converter module and the load. This is shown in FIG. 2 with interrupted connecting lines illustrated.

In most cases, the

Avalanche effect / avalanche breakdown effect after switch-on during a start-up phase, usually only during a few cycles, ie, approximately in a period of 6 - 12 ms, in particular 8 - 10 ms. More precisely, the start-up phase lasts until the secondary side of the converter, the capacitors are charged and the converter is settled.

In order to avoid the avalanche effect, it is provided to implement a so-called "soft start" function in the control unit, ie the control unit controls the converter switch in a special way during the startup phase to change on period (T _o n-time), ie, the time in which the converter switch is turned on or is turned on. in the known converter modules would for example, the T _on -time of the transducer switch to a fixed value, for example 4 microseconds (] is) determined. in order to avoid now the avalanche, or avalanche breakdown effect, the invention provides, during the starting phase, the T _OI, -time first to choose ge ing or limit to a low value and then over the To increase the duration of the start-up phase successively.

For this reason, instead of a period of 4] is initially a period of 1 s be chosen. In fixed or variable intervals, the T _on time can then be increased. For example, at intervals of one millisecond (ms), the T _on time may be increased by at least one microsecond until a maximum T _cn time is reached for the transducer switch. Overall, therefore, in the start-up phase, for example, a T _on time of 1-12 microseconds, in particular in the range of 4-10 microseconds set become. The time for the start-up phase can be permanently stored in the control unit.

However, it is also possible for the duration of the startup phase and / or the switch-on time period to be selected as a function of, for example, a measured value or parameter supplied to the control unit, for example a parameter fed back from the secondary side. In particular, the time intervals at which the switch-on time period is increased can also be selected dynamically.

It is also possible that a table in the form of a look-up table is stored in the control unit, and thus time intervals for increasing the EinsehaltZeitdauer or the duration for the start-up phase depending on a control unit supplied parameters are selected. For example, by a detection function, not shown, a converter module recognize a connected load. Therefore, when information about the connected load is transmitted to the control unit, the start-up phase or the turn-on time periods can be set depending thereon. The control unit can also regulate the switch-on time duration in a feed-forward mode, in particular without a measurement signal or parameter being fed back to the control unit. For example, the control unit can detect that the supply voltage / the supply current has been switched on. From this detection, the control unit can then regulate the switch-on time accordingly for a certain time, or restrict, and / or change as a function of time or based on data stored in a table.

By sequentially increasing the turn-on time period, a large voltage drop on the secondary side of the converter can be avoided since the control of the output voltage is much faster.

The so-called "soft start" function thus avoids the avalanche effect or the avalanche breakdown effect and also makes it possible to perform the control with a controller that only allows a relatively low control speed. Otherwise, ie without the "soft start" function, a more expensive regulator with higher speed would be needed to achieve a reduction of the avalanche effect or the avalanche breakdown effect with a constant _on- time.

The invention has the further advantage that, with appropriate adjustment and change of the turn-on period during the start-up phase, the converter switch can also be chosen to be designed in principle for lower power (i.e., a smaller transistor can be used, for example). Since high currents during the start-up hare be avoided by the control method according to the invention, a use of these smaller switching elements is possible and an avalanche effect or avalanche breakdown effect is not to be feared.

In summary, it can therefore be said that the solution according to the invention during the start / during the start-up phase, the maximum EinsehaltZeitdauer the Transducer switch limited, so that in this phase, the maximum current flowing through the converter switch is limited. More specifically, however, there is no fixed limit on the turn-on time of the converter switch, but the limit for the maximum turn-on time of the converter switch is ramped up or ramped up after power on / after the power reset in the startup phase. Overall, the duration of the Änlaufphase, ie the Einschaltzeitbegrenzung for the converter switch in the range of several Einschaltzyklen (for example, 5-15, especially 7-12 Einschaltzyklen).

Claims

claims

Converter module comprising:

- A primary side by means of a switch

clocked isolated converter, the

On the input side starting from an AC voltage, in particular a mains voltage, or a DC voltage can be supplied and starting from the secondary side of a load, preferably at least one light source is operable,

a control unit configured to control a switch-on period of the switch in a feed-forward mode and / or using a feedback measurement signal, and

wherein for a certain period of time or a certain number of switching cycles after switching on the DC or AC voltage, a constant or variable limitation of the switch-on time of the switch is given.

Converter module according to claim 1, wherein the control is a linear or ramp-like increase of

Switch-on time is.

Converter module according to claim 1 or 2, wherein the

Control unit, the turn-on time within the specified period of time in the same or variable

Changed distances.

Converter module according to one of the preceding claims, wherein the measuring signal is a supplied control parameter, in particular a return signal from the secondary side of the converter.

5. The converter module of claim 4, wherein the measurement signal is a current / voltage at the load and / or a parameter that reflects the type of the connected load.

6. converter module according to one of the preceding claims, wherein the specific period of time is 2 to 12 ms, in particular 4 to 10 ms. 7. converter module according to one of the preceding claims, wherein the control unit increases the turn-on time by a fixed or variable value.

8. converter module according to one of the preceding claims, wherein the control unit increases the switch-on time after each 1 ms by 1 \ is.

9. converter module according to one of the preceding claims, wherein the control unit, the switch-on time based on a stored function and / or a look

Determined up-table.

10. Ballast for lighting, in particular LEDs, with a converter module according to one of the preceding claims.

11. luminaire with a ballast according to claim 10.

12. Method for the operation of a converter module,

in which

a control unit, a switch-on period of a primary-side clocked by a switch electrically isolated converter, the input side starting from an AC voltage, in particular a mains voltage, or a DC voltage can be supplied and starting from the secondary side of a load, preferably at least one light source is operable in a feed-forward operation and / or under

Using a feedback feedback signal regulates, wherein for a certain period of time or a certain number of switching cycles after switching on the DC or AC voltage, a constant or variable limitation of the switch-on time of the switch is given.