EP2555585B1 - Power supply device for a jar heater and method for its operation - Google Patents

Description

The invention relates to a power supply device for a crucible heater. The invention also relates to a method for operating the power supply unit.

For melting the initial weight in crucible heaters, in particular in crystal growing systems, e.g. in the Czochralski process, usually low-resistance graphite heaters are used. In known power supply devices, the heating power required for this purpose is provided by actuators (thyristor), which operate on the principle of phase control. These power supply devices have a power input and one or more DC outputs. It follows through the operation of these known power supply devices mostly the disadvantages listed below.

The harmonics generated by the power supply device, so-called harmonics, lead to increased network losses. Industrial customers are therefore encouraged by their energy supplier to take appropriate measures to reduce the network feedback caused by them. Since a recorded reactive power is charged separately when the minimum value defined by the energy supplier for the power factor is not taken into account, reactive power losses must be limited by separate technical measures. For example, passive or active filter circuits are used for this purpose. Alternatively, a power supply in the form is known that the interaction caused by a linear Grobstellgliedes (variable transformer) and a fast fine actuator, the input-side noise caused by the power supply can be substantially reduced. Compensation systems are used to improve the power factor of the power supply.

The known power supply devices for crucible heating operate mostly in the partial load range. Typically, power supplies that operate on the principle of phase control, such as. Thyristor, in the partial load range, a relatively low efficiency, which is generally accepted.

The superimposed alternating current, also called ripple current, generated by known power supply systems on the secondary side can adversely affect the temperature control process of a crucible heater, since a reduced signal-to-noise ratio occurs at the sensor inputs of the temperature control. Furthermore, this ripple current on the graphite heater leads to undesirable side effects. For example, mechanical vibrations of the graphite heater may occur. In addition, the electromagnetic alternating fields generated by the ripple current can produce unpredictable magnetic fields in the crucible and thus negatively influence the crystal growth process, since, conversely, defined and superposed magnetic fields have a positive effect, see, for example, US Pat DE 10 2009 027 436 A1 , Interference voltages on the output side are attenuated by active and passive filters.

Under certain circumstances occurring network disturbances in the supply network of the power company or in the home network, such as flicker, peaks or voltage dips, lead in the known power supply systems due to the principle of phase control or wave packet control to secondary side noise emissions and thus to a reduced Signal to noise ratio at the sensor inputs of the temperature control. This in turn can lead to quality disturbances in the process, ie the regulation of the heating power, up to the process loss. If disturbances in the power supply occur, it can lead to the termination of the process. Generally, active and passive line filters are used to counteract the effects of short-term power disturbances on a crystal pulling process. Failures of systemically relevant Components of the power supply usually lead to a process interruption.

From the DE 10 2006 032 640 A1 is a converter for generating active power for the induction heating of melts known. This includes a rectifier, a DC link and then at least two inverters, each of which feed an induction coil for inductive heating of the respective melt. An AC supply of induction coils is also from the DE 10 2007 051 666 A known.

An object of the invention is to avoid or reduce the above-mentioned disadvantages of known power supply devices, in particular to lower the system perturbations generated during operation, to reduce the ripple current on the output side and to increase the efficiency.

Another object of the invention is to increase the availability of the power supply and thus the stability of the crystal pulling process.

This object is achieved with a power supply device for a crucible heater with the features of claim 1.

In this case, each power supply module comprises three identical submodules, which can be connected to one another via an internal system bus. Each sub-module includes a rectifier unit and a power factor correction stage. The power factor correction stage, also called PFC stage, allows a significant reduction of the network perturbation compared to known power supply devices for crucible heating.

The power factor correction stage is followed by clocked power stages. This allows the quality of the output voltage compared to known power supply devices be significantly improved, since the ripple current is reduced. At a reduced Rippelstrom occur only small inductively generated transverse forces in the heating circuit, for example on a graphite heater. As a result, mechanical vibrations of the graphite heater are reduced and its life thus extended.

With regard to the method, this object is achieved according to the invention by the features of the independent method claim. Thereafter, in a method for operating such a power supply device for a crucible heater, it is provided that the power supply modules are activated or deactivated separately for each heating circuit as a function of a course of the process and / or when disturbances occur in individual power supply modules.

The invention is based on the recognition that for the operation of crucible heaters, especially in crystal growing systems, high power, for example in the range of 200 to 500 kW, are required, with currents of several thousand amps flow. The performance must be built precisely and at the same time safety aspects due to the high currents must be considered. This knowledge is implemented so that similar power supply modules are interconnected in a cabinet.

The advantage of the invention is that network perturbations are reduced. Separate measures for network filtering are therefore usually not necessary. Depending on the current load requirements, individual power supply modules can be switched on or off in order to operate the active power supply modules in the best possible operating point and thus to achieve an improved power factor. The efficiency can be improved, especially in the partial load range. Thus, separate measures, such as the operation of the power supply to a compensation system, not necessary. In this way, costs can be saved. Primary-side power disturbances, such as flicker, peaks or voltage dips, make themselves noticeably less noticeable on the output side in the power supply device according to the invention than in the case of known power supply devices. The emission of temporary electromagnetic interference fields in the direction of the crucible heating is thus avoided and increased process stability, in particular of a crystal growth process, is the result.

Advantageous embodiments of the invention are the subject of the dependent claims. This used backlinks point to the further development of the subject matter of the main claim by the features of the respective subclaim; they should not be construed as a waiver of obtaining independent, objective protection for the feature combinations of the dependent claims. Furthermore, with a view to an interpretation of the claims in a closer specification of a feature in a subordinate claim, it can be assumed that such a restriction is not present in the respective preceding claims.

In one embodiment, the power supply device includes a heater controller connected between the process controller and the power modules for controlling and monitoring the power modules. The heater controller is passed through the process controller, which receives status and error messages from various process monitoring components, e.g. Temperature monitoring, cooling water monitoring, pressure monitoring, receives.

If each power supply module on the power supply unit has three-phase input connections, unbalanced network loads can be avoided.

In one embodiment, each power module may include a communication interface for communicating status and control information with the process controller or heater controller. Status and error messages may be e.g. by an LED (Light Emitting Diode) display, which is for example arranged directly on a front of the power supply module or submodule, via an HMI (Human Machine Interface, Human Machine Interface) to a control cabinet, in which the power supply device is arranged , and are displayed via the communication interface.

In the method, it is optionally provided that, in the event of a malfunction of one of the power supply modules, a signal is transmitted via a communication interface from the defective power supply module to a heating control device connected between the process control device and the power supply modules and the heating control device deactivates the defective power supply module. For this purpose, the heating control device sends a corresponding signal for deactivating the defective power supply module.

Alternatively, it can be provided that in the event of a malfunction of one of the power supply modules, a signal is transmitted via a communication interface from the defective power supply module to the process control device and the process control device then deactivates the defective power supply module. For this purpose, a corresponding control signal is sent from the process control device to the power supply module. This prevents defective power supply modules from having negative effects on the output voltage or causing system perturbations if they continue to operate.

In one embodiment, the power of the deactivated power supply module may be additionally or at least partially allocated to the power supply module (s) that are still active in the associated heating circuit, if the power supply module (s) associated therewith are Heating circuit required power is equal to or less than a maximum power of the active power modules, ie a sum of the maximum power of the power supply modules still available in the corresponding heating circuit. This allows a higher availability of the power supply device. In case of failure of a power supply module, the recovery time of the power supply is then much shorter than, for example, in known power supply devices. Thus, the crucible pulling system can be put into operation much faster.

An unneeded power module may be disabled in one embodiment, and the unneeded power module may be automatically re-activated in the event of a failure or failure of a paralleled power module. This makes it possible to optimize the operating point of the power supply device, in particular in the partial load range.

Alternatively, an unneeded power module can be disabled and the power module that is not required can be activated manually or automatically in the event of a failure or failure of a paralleled power module, optionally with a confirmation callback.

The operating modes for the deactivated power supply modules are either the "Hot Standby Mode" (AC input active) or the "Cold Standby Mode" (AC input deactivated). The modes of operation can be applied to a power module as needed; for example, if multiple power modules are disabled, part of the power modules that are disabled can be operated in "hot standby mode" and another portion in "cold standby" mode.

In one embodiment, the power supply module or modules connected in parallel to a deactivated power supply module can at least partially reduce the power of the deactivated power supply module Take over the power supply module. For example, with three power supply modules in a heating circuit, one of which is deactivated, the two active power supply modules each take over half of the power of the deactivated power supply module and can thus be operated in a lower operating point.

The invention is implemented in software in one embodiment. The invention is therefore on the one hand also a computer program with computer executable program code instructions and on the other hand a storage medium with such a computer program and finally also a process control device or a heating control device with a processing unit loaded in its memory as means for carrying out the method and its embodiments such a computer program or is loadable. The heater controller may equally perform all the tasks mentioned above and below in connection with the process controller.

FIG 1

ein Ausführungsbeispiel der erfindungsgemäßen Stromversorgungsvorrichtung,

FIG 2

eine primäre Spannungsversorgung und Kühlwasserversorgung,

FIG 3

ein weiteres Ausführungsbeispiel der erfindungsgemäßen Stromversorgungsvorrichtung,

FIG 4

ein Beispiel für eine optimierte Stromversorgung für die Stromversorgungsvorrichtung aus FIG 1,

FIG 5

ein Beispiel für eine Störung eines Stromversorgungsmoduls in der Stromversorgungsvorrichtung aus FIG 1 und

FIG 6

ein Beispiel für ein Verfahren zum Betrieb einer erfindungsgemäßen Stromversorgungsvorrichtung.

An embodiment of the invention will be explained in more detail with reference to the drawing. Corresponding objects or elements are provided in all figures with the same reference numerals. Show it:

FIG. 1

An embodiment of the power supply device according to the invention,

FIG. 2

a primary power supply and cooling water supply,

FIG. 3

a further embodiment of the power supply device according to the invention,

FIG. 4

an example of an optimized power supply for the power supply device FIG. 1 .

FIG. 5

an example of a failure of a power supply module in the power supply device FIG. 1 and

FIG. 6

an example of a method for operating a power supply device according to the invention.

FIG. 1 shows a schematic representation of an embodiment of the power supply device 10 according to the invention. The power supply device 10 includes five power supply modules 12, 14, 16, 18, 20, which are arranged in a control cabinet 22. The outputs 24 of a first and second power supply module 12, 14 are connected in parallel by means of a busbar (not shown) and supply a first heating circuit 26 of a crucible heater 28. The outputs 29 of a third, fourth and fifth power supply module 16, 18, 20 are also connected in parallel and supply a second heating circuit 30 to the crucible heater 28. The power supply modules 12-20 each include three identical sub-modules (not shown) which are interconnected via an internal system bus (not shown). Each submodule typically consists of a rectifier unit, a power factor correction (PFC) stage, a power converter with transformer, and a wide range output (all not shown). Each Power Supply Module 12-20 also has a communication interface to communicate and exchange status and control information, as described below. The control and monitoring of the individual power supply modules 12-20 is performed by a heating control device 32, which communicates via a communication interface 34 with the power supply modules 12-20 and is disposed within the control cabinet 22. However, it is equally possible that the heater control device 32 is disposed outside of the cabinet 22. The heating control device 32 is connected to a communication interface 34 of a process control device 36, which receives status and error messages from individual components such as cooling water monitoring 38, pressure monitoring 40, temperature monitoring 42 for process monitoring and is controlled by them. The process controller 36 includes a processing unit 44 and a memory 46 for executing a computer program for process monitoring and control. Instead of the process control device 36, the heating control device 32 may also have a processing unit and a Memory includes (both not shown) to run or store a computer program for process monitoring.

In FIG. 2 an example of a primary power supply 48 for the power modules 12-20 is shown schematically. The power supply 48 comprises a switching field 50 with which a supply voltage 51 is fed directly to the power supply modules 12-20. Each power supply module 12-20 is individually connected to a cooling water circuit 52.

FIG. 3 shows a further embodiment of a power supply device 54 according to the invention, in which the power supply modules 12-20 are connected directly to the communication interface 34 of the process control device 36 and are directly monitored and controlled by the process control device 36.

In FIG. 4 is an example of an optimized power supply for the power supply device 10 from FIG. 1 shown. In the partial load range, a no longer required power supply module 20 is deactivated. For this purpose, a corresponding control signal 56 is sent from the heating control device 32 to the power supply module 20 to be deactivated. Depending on requirements, it can be operated in the "hot standby" or "cold standby" mode, ie, if required, either automatically reactivated or switched on manually, for example if a fault occurs in one of the power supply modules 16 connected in parallel to the deactivated power supply module 20 via the communication interface. 18 is displayed. To the power supply modules 16, 18, which are still active in the second heating circuit 30, a corresponding control signal 58 for transferring in each case half of the power from the deactivated power supply module 20 is respectively sent. So they can be operated in a cheaper operating point. Also, another power distribution to the remaining in the second heating circuit 30 active power supply modules 16, 18 can be determined so that, for example, takes over a 30% and the other 70% of the power of the deactivated power supply module 20. The values of the power take-overs can be determined in such a way that the remaining active power supply modules 16, 18 can be operated in the most favorable operating point possible.

FIG. 5 shows an example of a failure of a power module 20 in the power supply device 10. From the power supply module 20, a fault signal 60 is sent to the heater controller 32. The power supply module 20 with the fault is then deactivated by the heater controller 32. At the same time, the heating control device 32 sends a corresponding control signal 62 to the power supply modules 16, 18 remaining in the associated second heating circuit 30, so that the power from the defective power supply module 20 is additionally allocated to each of them in addition to 50% if a heating power required in the second heating circuit 30 is less than or equal to the sum of the maximum power of the still available, functioning power supply modules 16, 18.

After completion of the process, e.g. a crystal growing process, by replacing the defective power supply module 20, the operational readiness of the power supply device can be restored in the short term and with low service cost. The modular design of the power supply devices 10, 54 makes it possible to adapt the power supply devices 10, 54 also for other systems, in particular crystal growing systems, with changed power requirements of the heating circuits.

FIG. 6 shows an example of a method 64 for operating a power supply device 10, 54 according to the invention. In a first step 66, a signal is transmitted via a communication interface from the defective power supply module to the process control device. In a second step 68, the process control device deactivates using a corresponding control signal, the defective power supply module. In a third step 70, the power of the deactivated power supply module is additionally proportionally assigned to the power module (s) active in the associated heater circuit by a corresponding control signal from the process control device to the power module (s) active in the associated heater circuit when the power required in the associated heater circuit is less than or equal to maximum power of the active power modules.

A few aspects of the presently filed description can be briefly summarized as follows: A power supply device 10, 54 for a crucible heater 28, comprising at least one heating circuit 26, 30, each having at least two power supply modules 12, 14, 16, 18, 20, wherein in the or each heating circuit 26, 30 outputs 24, 29 of the at least two power supply modules 12-20 are connected in parallel, and a process control device 36 for controlling the power supply modules 12-20 indicated.

Claims (14)

1. Power supply device (10) for a crucible heater (28), comprising
   at least one heating circuit (26,30), which in each case comprises at least two power supply modules (12,14,16,18,20), and
   a process control device (36) for controlling the power supply modules (12,14,16,18,20),
   wherein output terminals (24,29) of the at least two power supply modules (12,14,16,18,20) are connected in parallel in the or each heating circuit (26,30),
   characterised in that
   each power supply module (12,14,16,18,20) comprises three identical submodules which are connected to one another via an internal system bus,
   each submodule comprises a rectifier unit and a power factor correction stage, and
   clocked output stages are connected in series to the power factor correction stage.
2. Power supply device (10) according to claim 1, with a heating control device (32) connected between the process control device (36) and the power supply modules (12,14,16,18,20), for controlling and monitoring the power supply modules (12,14,16,18,20).
3. Power supply device (10) according to claim 1 or 2, wherein each power supply module (12,14,16,18,20) is three-phase-connected on the input side.
4. Power supply device (10) according to one of claims 1 to 3, wherein each power supply module (12,14,16,18,20) comprises a communication interface.
5. Method for operating a power supply device (10) for a crucible heater (28) according to one of the preceding claims, wherein the power supply modules (12,14,16,18,20) are activated or deactivated separately for each heating circuit (26,30) as a function of a process flow and/or upon the occurrence of faults in individual power supply modules (12, 14, 16, 18, 20).
6. Method according to claim 5, wherein a signal (56) is transmitted via a communication interface from the defective power supply module (12,14,16,18,20) to a heating control device (32) connected between the process control device (36) and the power supply modules (12,14,16,18,20) in the event of a fault in one of the power supply modules (12,14,16,18,20) and the heating control device (32) deactivates the defective power supply module (12,14,16,18,20).
7. Method according to claim 5, wherein a signal (56) is transmitted via a communication interface from the defective power supply module (12,14,16,18,20) to the process control device (36) in the event of a fault in one of the power supply modules (12,14,16,18,20) and the process control device (36) deactivates the defective power supply module (12, 14, 16, 18, 20).
8. Method according to claim 6 or 7, wherein the output of the deactivated power supply module (12,14,16,18,20) is additionally assigned proportionately to the one or more power supply modules (12,14,16,18,20) active in the associated heating circuit (26,30), if the output required in the associated heating circuit (26,30) is less than or equal to a maximum output of the active power supply modules (12, 14, 16, 18, 20).
9. Method according to one of claims 5 to 8, wherein a power supply module (12,14,16,18,20) that is no longer required is deactivated, and wherein the power supply module (12,14,16,18,20) that is no longer required is automatically activated in the event of a failure or fault in a power supply module (12,14,16,18,20) connected in parallel.
10. Method according to claim 9, wherein the one or more power supply modules (12,14,16,18,20) connected in parallel to a deactivated power supply module (12,14,16,18,20) takes over the output of the deactivated power supply module (12,14,16,18,20) at least proportionately.
11. Computer program with program code means, in order to execute all steps of any of claims 5 to 10 if the program is run on a process control device (36) or heating control device (32).
12. Computer program product with program code means which are stored on a computer-readable data carrier, in order to execute a method according to any of claims 5 to 10, if the program product is run on a process control device (36) or heating control device (32).
13. Digital storage medium, in particular a floppy disk, with electronically readable control signals which can interact with a programmable process control device (36) or heating control device (32) such that a method according to one of claims 5 to 10 is executed.
14. Process control device (36) or heating control device (32) with a processing unit (44) and a memory (46), into which a computer program according to claim 11 is loaded, which is run by the processing unit (44) during operation of the device.

Images