Induction heating device, system, production line, method, and use

Abstract

The invention relates to an induction heating device for heating a metallic good, comprising a number of at least two resonant circuits for generating a magnetic field for heating the metallic good, and a power supply device for supplying the resonant circuits with electrical energy, comprising a disconnect switch for connecting the induction heating device to an electrical power supply, and at least one inverter for converting a direct current into an alternating current for supplying energy to a resonant circuit, wherein the power supply device has a switching device, wherein the switching device is configured to enable at least indirect energy coupling between the disconnect switch and the resonant circuits, wherein the number of simultaneously energy-coupling resonant circuits is smaller than the number of resonant circuits of the induction heating device.

Description

[0001] The invention relates to an induction heating device, a system, a production line, a method and a use.

[0002] Production lines for the manufacture and / or processing of semi-finished products, intermediate products, and / or finished products made of ferrous, steel, and / or non-ferrous metal materials consist of several devices in which the intermediate product, pre-product, and / or finished product is subjected to one or more process steps. These devices can include, for example, heating or cooling devices, transport devices, forming devices, cleaning devices, chemical treatment devices, surface coating devices, cutting or joining devices, and combinations thereof. The process steps can include, for example, temperature raising or lowering, transport, forming, cleaning, chemical treatment, surface coating, cutting or joining, and combinations thereof.

[0003] Increasing the temperature of the pre-product, intermediate product, and / or final product is a prerequisite for many process steps and represents a crucial step in the process. Induction heating devices can be used for this purpose, among other methods. These induction heating devices can be installed at various points within the production line.

[0004] In induction heating using an induction heating device, an inductor is excited to oscillate, particularly in the medium frequency range. It is known to integrate this inductor into a so-called resonant circuit with the aid of an additional capacitor. This resonant circuit is excited by an inverter, for example, by switching on voltage pulses near the resonant frequency of the circuit using a bridge circuit, half-bridge circuit, or a single switch.

[0005] Typically, a mains voltage, for example a single-phase or multi-phase alternating voltage, is first rectified, smoothed, and the DC voltage is fed to an inverter, which excites the inductor.

[0006] The invention is based on the objective of providing an improvement or an alternative to the prior art.

[0007] According to a first aspect of the invention, the problem is solved by an induction heating device for heating a metallic good, in particular a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material, comprising: comprising a number of at least two resonant circuits, in particular three, four, five, six or more resonant circuits, for generating a magnetic field for heating the metallic material, and a power supply device for supplying the resonant circuits with electrical energy: a disconnect switch for connecting the induction heating device to an electrical power supply, and at least one inverter, in particular two, three, four, five, six or more inverters, for converting a direct current into an alternating current for supplying energy to a resonant circuit, wherein the power supply device has a switching device, wherein the switching device is configured to enable at least indirect energy coupling between the disconnect switch and the resonant circuits, wherein the number of simultaneously energy-coupling resonant circuits is smaller than the number of resonant circuits of the induction heating device.

[0008] The following terminology should be explained in this regard: First, it should be expressly pointed out that, within the scope of the present patent application, indefinite articles and numerical indications such as "one", "two", etc. are generally to be understood as "at least" indications, i.e., as "at least one...", "at least two...", etc., unless it is expressly evident from the respective context or it is obvious or technically necessary for the person skilled in the art that only "exactly one...", "exactly two...", etc., can be meant.

[0009] In the context of the present patent application, the term "in particular" is always to be understood as introducing an optional, preferred feature. The term is not to be understood as "namely" or "namely".

[0010] An "induction heating device" is understood to be a device designed for the inductive heating of a metallic object using electrical energy. The induction device, comprising at least one resonant circuit, generates an alternating magnetic field. If the metallic object is in contact with this alternating magnetic field, the field induces an electrical voltage in the object, resulting in an electric current, particularly an alternating current. This current always flows in closed paths, can therefore also be called an eddy current, and, according to Joule losses, causes the metallic object to heat up. In the case of a ferromagnetic metallic object, this heating occurs until the Curie temperature is reached, at which point ferromagnetic or...The ferroelectric properties of the metallic material have completely disappeared, and heating also occurs as a result of remagnetization losses.

[0011] An induction heating device offers the advantage of achieving direct heating of the metallic material, since the heat is generated within the metallic material itself and does not need to be introduced from the outside via conduction, convection and / or radiation through the surface of the metallic material.

[0012] A "metallic good" means any product containing an electrically conductive ferrous material, a steel material, and / or a non-ferrous metal material. In particular, a metallic good can be understood to be any semi-finished product, any intermediate product, any intermediate product, or any finished product that is electrically conductive.

[0013] A coil of an induction heating device may have less than one full turn, one full turn and / or more than one full turn, in particular more than or equal to two turns, more than or equal to three turns or more than or equal to four turns.

[0014] A magnetic connection between a metallic material and an alternating magnetic field can be established by longitudinal field induction and / or transverse field induction. In longitudinal field induction, the magnetic field lines run essentially in the longitudinal direction of the metallic material. In transverse field induction, the magnetic field lines run in the metallic material essentially in a transverse direction, particularly in the thickness direction and / or in the width direction. If the metallic material is a sheet, the magnetic field lines in transverse field induction can enter and exit the sheet essentially in the thickness direction.

[0015] A "power supply device" is understood to be a device designed to provide electrical energy for the operation of at least one resonant circuit, in particular with an electric current of suitable current intensity, suitable voltage, and / or suitable frequency. A power supply device may be configured to provide electrical energy for a plurality of resonant circuits, in particular for at least two, three, four, five, six, or more resonant circuits.

[0016] An energy supply device can be designed to condition and provide electrical energy for the resonant circuit for the efficient operation of a resonant circuit, in particular with the optimal frequency and / or the optimal phase angle to the phase angle of the resonant circuit.

[0017] An energy supply device may be designed to prevent or reduce any adverse effects on an electrical power supply caused by the operation of a resonant circuit.

[0018] A power supply device is designed for connection to an electrical power supply. An electrical power supply can be understood to be a three-phase power grid. An electrical power supply can be an alternating current (AC) supply or a direct current (DC) supply.

[0019] A power supply can have medium voltage or high voltage.

[0020] High voltage can be greater than or equal to 36 kV, preferably greater than or equal to 60 kV, and particularly preferably greater than or equal to 100 kV. Furthermore, high voltage can be greater than or equal to 150 kV, preferably greater than or equal to 200 kV, and particularly preferably greater than or equal to 300 kV. High voltage can be less than or equal to 400 kV. Furthermore, high voltage can be less than or equal to 300 kV, preferably less than or equal to 200 kV, and particularly preferably less than or equal to 150 kV.

[0021] Medium voltage can be greater than or equal to 1 kV AC or greater than or equal to 1.5 kV DC, preferably greater than or equal to 2 kV and particularly preferably greater than or equal to 10 kV. Medium voltage can be greater than or equal to 15 kV, preferably greater than or equal to 20 kV and particularly preferably greater than or equal to 30 kV. Medium voltage can be less than or equal to 36 kV. Furthermore, medium voltage can be less than or equal to 30 kV, preferably less than or equal to 20 kV and particularly preferably less than or equal to 15 kV.

[0022] Preferably, the voltage levels can be defined according to IEC 60519-4.

[0023] A "disconnect switch" is a switching element designed to close an electrical circuit or de-energize it, particularly for service and / or maintenance work or operational interruptions. A disconnect switch can also be designed as a circuit breaker for high currents.

[0024] Optionally, the power supply device includes a single-phase disconnect switch or a three-phase disconnect switch.

[0025] The disconnect switches proposed here ensure that the power supply device can be switched off without voltage.

[0026] Preferably, a disconnect switch connects the power supply unit to earth potential in the open position. This increases safety against electric shocks.

[0027] An "inverter" is a power electronic device or electrical circuit designed to convert direct current (DC) into alternating current (AC). The resulting AC frequency depends on the inverter's switching algorithm.

[0028] An inverter circuit can be controlled by applying a pulse width modulation algorithm.

[0029] In particular, the inverter can be designed for the operation of a specific resonant circuit. When using different resonant circuits, it is advantageous to use different inverters specifically tailored to the different resonant circuits, whereby a rectifier and / or a smoothing circuit and / or a transformer and / or a disconnect switch can be designed identically for a plurality of different resonant circuits.

[0030] A "switching device" is understood to be an assembly that is designed to switch an electrically conductive connection by means of a switch, i.e. to establish or break an electrically conductive connection between at least two contacts.

[0031] A switching device can be designed to switch an alternating current. The switching device can accordingly be arranged between an inverter and at least one resonant circuit.

[0032] A switching device can be configured to switch a direct current. The switching device can be arranged between a rectifier or a smoothing circuit or a DC power supply and at least one resonant circuit.

[0033] Preferably, a switching device has a plurality of switching options between a power source, preferably an AC or DC source, and at least two loads, preferably three, four, five or more loads, in particular resonant circuits and / or inverters. The switching device can be configured to disconnect or establish exactly one connection between a power source and exactly one of the loads, or to switch to another load. The switching device can be configured to disconnect or establish or switch two, three, four or more connections between exactly one power source and two, three, four or more of the loads, in particular to switch them in pairs.

[0034] A switching device can be configured to include a plurality of power sources, wherein each power source can be connected, disconnected, or switched with exactly one or more loads. Preferably, the switching device is configured such that less than one connection can be made between a load and at least two power sources simultaneously.

[0035] Here, a power supply device for an induction heating device is proposed, comprising a disconnect switch, at least two inverters, and a switching device, wherein the disconnect switch is configured for connecting the power supply device to an electrical power supply, wherein an inverter is configured for converting a direct current into an alternating current for powering a resonant circuit, wherein the switching device is configured to enable at least indirect energy coupling between the disconnect switch and a plurality of resonant circuits, and wherein the number of simultaneously energy-coupling resonant circuits is smaller than the number of resonant circuits that can be at least indirectly connected to the switching device.

[0036] The power supply unit allows at least one component to be used alternately and / or intermittently for a number of resonant circuits, although the majority of these circuits cannot be operated simultaneously. In other words, certain components of the power supply unit, particularly the disconnect switch, are installed only as often as necessary for the practical simultaneous operation of the installed / installable resonant circuits, while the resonant circuits can be installed at any point in a production line where heating may be required.

[0037] Alternatively, an induction heating device is proposed here, which has a power supply device as described above and at least two resonant circuits.

[0038] This allows different resonant circuits at various points in a production line to be operated alternately and / or intermittently using a common component of the power supply system, which is designed only for the operation of some or one of the available resonant circuits.

[0039] Power supply systems account for a large portion of the investment costs of an induction heating device. The power supply system proposed here can reduce the investment costs of an induction heating device, particularly for devices with spatially distributed resonant circuits.

[0040] Often, not all resonant circuits in a production line are operated simultaneously. Currently, resonant circuits are primarily operated depending on the product being manufactured. Thus, a production line might have a total of six resonant circuits, but in any case, only a maximum of three are operated at the same time. If each induction heating device includes all components of a power supply unit, the associated investment costs are incurred in full.

[0041] Modern production lines typically need to be able to flexibly adapt to a wide range of metallic products, each with its own specific temperature requirements during the various process steps. Depending on the product, the products manufactured before and after it, the current energy price mix, and other factors, the most efficient operating mode for the production line may require the use of resonant circuits at different locations within the line.

[0042] The energy supply system proposed here can improve the flexibility of the production line, reduce reaction time during product changeovers, improve the energy efficiency of the production line in operating modes or with metallic goods that allow it, and shorten the structural length of a production line.

[0043] Optionally, a disconnect switch is provided for connecting the induction heating device to a DC power supply.

[0044] It is proposed here that the disconnect switch of the power supply device be designed to be connected to a DC power supply, preferably a DC power supply having a medium voltage or a low voltage.

[0045] The inverters of the power supply unit can be designed so that they can be indirectly connected to the DC power supply, preferably by being supplied with a medium-voltage DC voltage or a low-voltage DC voltage.

[0046] Low voltage can be greater than or equal to 120 V, preferably greater than or equal to 220 V, and particularly preferably greater than or equal to 240 V. Low voltage can be less than or equal to 1,000 V, and particularly preferably less than or equal to 900 V. Low voltage can be less than or equal to 600 V, preferably less than or equal to 240 V, and particularly preferably less than or equal to 220 V.

[0047] Optionally, the disconnect switch is provided for connecting the induction heating device to an AC power supply, wherein the power supply device between the disconnect switch and the at least one inverter has at least one rectifier, in particular two, three, four, five, six or more rectifiers, for converting an alternating current into a direct current to supply power to the at least one inverter.

[0048] The following definition should be explained: A "rectifier" is an electrical device that converts alternating current, which periodically changes direction, into direct current.

[0049] A rectifier can be a three-phase rectifier. The rectifier can be designed to be supplied with medium voltage or low voltage.

[0050] A rectifier can have a topology that includes and / or consists of diodes. A three-phase rectifier can be an uncontrolled n-times 6-pulse diode rectifier, in particular a 6-pulse diode rectifier, a 12-pulse diode rectifier, an 18-pulse diode rectifier, and so on.

[0051] By using transistors and / or thyristors, a rectifier can be advantageously controlled or regulated. This can make it possible to ensure that the power supply equipment, in order to comply with the requirements of a power supplier, is connected to a static reactive power compensator.

[0052] The power supply unit expediently includes a transformer between the disconnect switch and at least one rectifier.

[0053] The following definition should be explained: A "transformer" is a component that transfers electrical energy from one circuit to another without a conductive connection between the two circuits. The transformer converts alternating current (AC) at the primary side of the transformer into alternating current at the secondary side.

[0054] A transformer can be a three-phase transformer.

[0055] The transformer can be a high-voltage to medium-voltage transformer, which converts a high voltage on a primary side of the transformer into a medium voltage on a secondary side of the transformer.

[0056] The transformer can be a high-voltage to low-voltage transformer, which converts a high voltage on a primary side of the transformer into a low voltage on a secondary side of the transformer.

[0057] The transformer can be a medium-voltage to low-voltage transformer, which converts a medium voltage on a primary side of the transformer into a low voltage on a secondary side of the transformer.

[0058] Optionally, the disconnect switch can be designed as a medium-voltage switchgear.

[0059] The following definition applies: A "medium-voltage switchgear" is understood to be a central arrangement of power disconnectors and / or fuses and / or circuit breakers that serve to protect and / or control and / or ground the power supply equipment.

[0060] According to a preferred embodiment, the at least one inverter and / or the at least one rectifier are configured for medium-voltage operation. In other words, the at least one rectifier and / or the at least one inverter are configured for supplying a medium voltage.

[0061] Preferably, the power supply device has a smoothing circuit between the disconnect switch and the at least one inverter, in particular between the at least one rectifier and the at least one inverter.

[0062] The following definition should be explained: Deriving a DC voltage from an AC source within a power supply, particularly within a power supply device, can lead to ripple voltage, especially when using a diode rectifier. Ripple voltage is a periodic residual fluctuation in the output voltage of a rectifier.

[0063] To smooth out the ripple voltage, a rectifier can be connected to a "smoothing circuit" which is designed to smooth out the ripple voltage.

[0064] The smoothing circuit can include a capacitor connected in parallel to a rectifier circuit.

[0065] The smoothing circuit can include an inductor connected in series with a rectifier circuit.

[0066] According to a suitable embodiment, a rectifier and an inverter can be energetically coupled to each other using DC busbars.

[0067] According to an optional embodiment, the power supply device has a DC converter between the disconnect switch and the at least one inverter, in particular between the at least one rectifier and the at least one inverter.

[0068] The following definition applies: A "direct current converter" is a power electronic device or electrical circuit designed to convert a direct current (DC) applied to the input of the DC converter with a voltage supplied to the input into a direct current at the output of the DC converter with a higher, lower or inverted voltage level.

[0069] A DC / DC converter, placed between a rectifier and an inverter, allows the voltage level between the rectifier and the inverter to be changed. In this way, a medium-voltage rectifier can be combined with a low-voltage inverter, thereby improving the overall efficiency of the power supply device.

[0070] Preferably, a switching device is arranged between a rectifier and at least two inverters, wherein the switching device is designed to to establish an energy coupling between the rectifier and exactly one inverter, and / or to establish an energy coupling between the rectifier and a group of inverters, in particular an energy coupling between the rectifier and a subset of the group of inverters.

[0071] Alternatively, in the case of an induction heating device already supplied with DC voltage, which may be connected to a local DC transmission network, a switching device may be arranged between the disconnect switch and at least two inverters, wherein the switching device is designed to to establish an energy coupling between the disconnect switch and exactly one inverter, and / or to establish an energy coupling between the disconnect switch and a group of inverters, in particular an energy coupling between the disconnect switch and a subset of the group of inverters.

[0072] The switching device proposed here is arranged between a rectifier or a disconnect switch and at least two inverters, so that the switching device is designed to switch in the area of ​​direct current transmission.

[0073] This advantageously allows the components of the power supply unit installed between the electrical power supply of the induction heating device and the switching device to be installed separately for each supplied resonant circuit. Instead, it is sufficient if the number of components installed upstream of the switching device is simply a single unit, with each component only needing to be adapted to the maximum electrical power simultaneously available from the induction heating device.Since it is intended that at least one resonant circuit of the induction heating device can be operated at a lower power than the total number of resonant circuits in the induction heating device, the rated power of the components up to the switching device can be dimensioned accordingly smaller compared to the sum of the rated powers of all installed resonant circuits, in particular the rated power of the disconnect switch and / or the transformer and / or the rectifier. Alternatively, the rated electrical power available from the power supply unit can also be provided by a number of individual components, especially components connected in parallel. For example, a number of transformers and / or a number of rectifiers can be connected in parallel upstream of the switching device without deviating from the aspect proposed here.The parallel-connected components can be designed in such a way that each can provide a portion of the required electrical nominal power.

[0074] Thus, an induction heating device can have at least one less rectifier and / or transformer and / or disconnect switch than resonant circuits.

[0075] Regarding the possible switching states of the proposed switching device, the device can be designed such that, of the majority of the resonant circuits connected to the individual switching device, up to exactly one resonant circuit can be simultaneously energy-coupled with the DC connection of the switching device. The majority of the resonant circuits connected to the switching device can be operated alternately and / or intermittently.

[0076] Alternatively, with regard to the possible switching states of the switching device proposed here, it can be provided that the switching device is designed in such a way that an energy coupling can be established between the DC connection of the switching device and a group of inverters, in particular an energy coupling between the DC connection of the switching device and a subset of the group of inverters, whereby it is also provided here that at least one fewer resonant circuit can be operated simultaneously compared to the total number of resonant circuits installed.It may be provided that a switching connection can be changed alternately or intermittently, or that a plurality of switching connections can be changed alternately and / or intermittently at the same time; in particular, it may also be provided that a pair of resonant circuits can be switched simultaneously, in particular that a first pair of resonant circuits can be switched simultaneously with a second pair of resonant circuits.

[0077] For example, a first pair of resonant circuits located in a front area of ​​a production line can be operated alternately or intermittently to a second pair of resonant circuits located in a rear area of ​​the production line.

[0078] It is advantageous to arrange a switching device between an inverter and at least two resonant circuits, wherein the switching device is designed to to establish an energy coupling between the inverter and exactly one resonant circuit for generating a magnetic field, and / or to establish an energy coupling between the inverter and a group of resonant circuits for generating a magnetic field each, in particular an energy coupling between the inverter and a subset of the group of resonant circuits.

[0079] The switching device proposed here is arranged between an inverter and at least two resonant circuits, so that the switching device is designed to switch in the area of ​​alternating current transmission.

[0080] This approach offers the advantage that the components of the power supply system do not need to be designed separately for each powered resonant circuit. Instead, they can each be dimensioned once and / or according to the maximum nominal power that can be simultaneously drawn by the resonant circuits, whereby parallel connections of individual components to achieve the necessary nominal power are also conceivable.

[0081] Thus, an induction heating device can have at least one fewer rectifier, inverter, transformer, and / or disconnect switch than resonant circuits. Furthermore, the induction heating device can be dimensioned with respect to the rated power supplied by the power supply unit such that this power is less than the sum of the rated powers of the resonant circuits comprised of the induction heating device.

[0082] It is understood that an induction heating device can also have a plurality of switching devices.

[0083] It may be provided, among other things, that the induction heating device can have at least two switching devices between at least one disconnect switch and each of a plurality of at least indirectly connected inverters, wherein the plurality of switching devices can also be connected in parallel to each other and can be connected to exactly one disconnect switch and / or exactly one transformer and / or exactly one rectifier.

[0084] It can also be provided that the induction heating device can have at least two switching devices between at least one inverter and each of a plurality of at least indirectly connected resonant circuits with preferably identical electrical properties, wherein the plurality of switching devices can also be connected in parallel to each other and can be connected to exactly one inverter and / or exactly one transformer and / or exactly one rectifier.

[0085] Furthermore, it may be provided that the induction heating device can have one or more switching devices between at least one disconnect switch and at least one plurality of inverters, as well as one or more switching devices between at least one inverter and at least one plurality of resonant circuits.

[0086] Parallel operation of a multiple resonant circuits on one inverter is also conceivable, whereby it is advantageous if the majority of the resonant circuits have the same electrical properties.

[0087] Preferably, the induction heating device is designed to be mechanically movable and / or at least partially mechanically movable.

[0088] The following terminology should be explained in this context: "Mechanically movable" means that the unit in question, in particular the induction heating device or the power supply unit, is detachably connected to the surface on which it is designed to stand, the unit has lifting devices for attaching the unit to a crane or the like, and / or the unit is supplied with electricity and / or operating fluids, in particular coolant, by means of detachable connecting means.

[0089] This allows the induction heating device to be flexibly deployed at different positions within a production line, minimizing the time required for line changeovers. The lifting slings enable the induction heating device to be moved as needed by a crane, forklift, and / or other dedicated transport equipment.

[0090] According to an advantageous embodiment, a single resonant circuit can be designed to be movable, so that it can be used alternately at different positions of a production line.

[0091] According to a suitable embodiment, the power supply device is designed to be mechanically movable and / or at least partially mechanically movable.

[0092] A part of a power supply device can in particular be a component of the power electronics of a power supply device, especially a transformer, a rectifier, a DC converter, an inverter and / or a smoothing circuit.

[0093] Optionally, a resonant circuit is designed for longitudinal field induction and / or transverse field induction.

[0094] The following should be explained in terms of terminology: A resonant circuit designed for "longitudinal field induction" can have a coil which encloses at least one edge of the metallic material, preferably at least two edges and particularly preferably four edges.

[0095] Preferably, a resonant circuit designed for longitudinal field induction has several turns of the coil wound transversely to the designated longitudinal extent of the metallic material, preferably at least two turns, preferably at least three turns and particularly preferably at least four turns, wherein the majority of the turns are preferably arranged compactly next to each other, wherein the shortest distance between two adjacent turns is preferably smaller than a transverse extent of a turn.

[0096] A resonant circuit designed for "cross-field induction" has a coil which extends predominantly in a plane, preferably in a meandering shape in a plane, wherein the coil preferably does not enclose any edge of the metallic material.

[0097] Preferably, a resonant circuit designed for "cross-field induction" comprises a first coil and a second coil, each extending predominantly in a plane, preferably each extending in a meandering pattern in a plane, wherein the coils preferably do not enclose any edge of the metallic material. The respective planes of extension can be arranged parallel to each other. The respective coils can be arranged symmetrically to each other. Preferably, the metallic material to be heated is passed between the coils, preferably in the plane of the mirror image.

[0098] A coil arrangement of this type, consisting of a first coil extending essentially in one plane and a second coil extending in a mirror-symmetrical manner, can also be used for longitudinal field induction if each coil forms a separate resonant circuit and the resonant circuits are operated in opposite directions, i.e., have a phase angle of the respective operating currents of preferably 180 degrees.

[0099] Advantageously, a resonant circuit designed for transverse field induction and a resonant circuit designed for longitudinal field induction can be operated on at least partially identical power supply equipment, thereby reducing the investment costs of a production line. In particular, the disconnect switch, rectifier, and smoothing circuit can be used equally and without modification for both a resonant circuit designed for transverse field induction and a resonant circuit designed for longitudinal field induction.

[0100] In principle, the inverter of the power supply unit can also be the same, although a different operating mode may be selected and / or a different control and / or regulation signal may be used for the inverter, in particular a different pulse width modulation signal.

[0101] It is advantageous to have an electrical connection between an inverter and a resonant circuit by means of a fluid-cooled busbar, in particular a busbar designed for internal cooling with a fluid.

[0102] Preferably, a busbar between an inverter and a resonant circuit can be cooled with a liquid coolant, in particular water, wherein the coolant is preferably located within the busbar and further preferably guided by the busbar. In this way, a busbar can be cooled, among other things, by forced convection.

[0103] Alternatively, a busbar can be cooled with a gaseous coolant, in particular with air or a different gas mixture. This allows the busbar to be cooled by forced convection and / or free convection.

[0104] According to a second aspect of the invention, the problem is solved by a system comprising a plurality of induction heating devices according to the first aspect of the invention.

[0105] It is understood that the advantages of an induction heating device described above according to the first aspect of the invention can be directly transferred to a system comprising a plurality of induction heating devices according to the first aspect of the invention.

[0106] It should be expressly noted that the subject matter of the second aspect can be advantageously combined with the subject matter of the preceding aspect of the invention, either individually or cumulatively in any combination.

[0107] According to a third aspect of the invention, the problem is solved by a production line for the manufacture and / or processing of a metallic good, in particular a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material, comprising an induction heating device according to the first aspect of the invention and / or a system according to the second aspect of the invention.

[0108] It is understood that the advantages described above of an induction heating device according to the first aspect of the invention and / or a system according to the second aspect of the invention are directly transferable to a production line for the manufacture and / or processing of a metallic good, in particular a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material, comprising an induction heating device according to the first aspect of the invention and / or a system according to the second aspect of the invention.

[0109] A production line can be a hot rolling mill, especially with a hot or warming insert, and / or a strip mill.

[0110] It should be expressly noted that the subject matter of the third aspect can be advantageously combined with the subject matter of the preceding aspect of the invention, either individually or cumulatively in any combination.

[0111] According to a fourth aspect of the invention, the problem is solved by a method for operating an induction heating device according to the first aspect of the invention, wherein at least two resonant circuits are operated alternately and / or intermittently at different points in a production line.

[0112] It is understood that the advantages of an induction heating device described above according to the first aspect of the invention can be directly transferred to a method for operating an induction heating device according to the first aspect of the invention.

[0113] It should be expressly noted that the subject matter of the fourth aspect can be advantageously combined with the subject matter of the preceding aspect of the invention, either individually or cumulatively in any combination.

[0114] According to a fifth aspect of the invention, the problem is solved by using an induction heating device according to the first aspect of the invention for the manufacture and / or processing of a metallic good, in particular a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material.

[0115] It is understood that the advantages of an induction heating device described above according to the first aspect of the invention are directly transferable to a use of an induction heating device according to the first aspect of the invention.

[0116] It should be expressly noted that the subject matter of the fifth aspect can be advantageously combined with the subject matter of the preceding aspect of the invention, either individually or cumulatively in any combination.

[0117] Further advantages, details, and features of the invention will become apparent from the exemplary embodiments described below. Specifically, the following will be shown: Figure 1: schematically showing a system comprising a plurality of induction heating devices according to the prior art; Figure 2: schematically showing a first embodiment of a system of induction heating devices; Figure 3: schematically showing a second embodiment of a system of induction heating devices; and Figure 4: schematically showing a third embodiment of a system of induction heating devices.

[0118] In the following description, identical reference numerals denote identical components or identical features, so that a description of a component in relation to one figure also applies to the other figures, thus avoiding repetitive descriptions. Furthermore, individual features described in connection with one embodiment can also be used separately in other embodiments.

[0119] A system 500 comprising a plurality of induction heating devices 100, in particular comprising seven induction heating devices 100, according to the prior art in Figure 1 The device for heating a metallic good (not shown) essentially consists of a plurality of independent induction heating devices 100, which have less than a direct functional connection between each other.

[0120] Basically, an induction heating device 100 consists of a power supply unit 20 and a resonant circuit 10, wherein the power supply unit 20 has at least an inverter 28 and a disconnect switch 22.

[0121] Each induction heating device 100 has at least one disconnect switch 22, exactly one inverter 28 and exactly one resonant circuit 10, wherein the resonant circuit 10 is configured to generate a magnetic field for heating the metallic material (not shown).

[0122] The disconnect switch 22 is designed to connect the induction heating device 100 to an electrical power supply (not shown).

[0123] The inverter 28 is designed to convert a direct current into an alternating current to supply energy to the resonant circuit 10 and is connected to the resonant circuit 10 by means of an alternating current transmission 29.

[0124] According to a first variant (not shown), the electrical power supply (not shown) can be a DC transmission network, in particular a medium-voltage DC transmission network. According to this variant, the inverter 28 can be connected to the electrical power supply directly via the disconnect switch 22 or indirectly via a DC transformer (not shown) and the disconnect switch 22 by means of a DC transmission line 27.

[0125] According to a second variant, the electrical power supply can be an alternating current supply, in particular a three-phase alternating current network. In this case, the power supply unit 20 has a rectifier 26, which can be connected to the inverter 28 directly via a DC transmission 27 and / or via a DC-DC converter (not shown). Furthermore, the power supply unit 20 can have a transformer 24. Thus, the electrical power supply (not shown) can be, among other things, a high-voltage power supply or a medium-voltage power supply, whereby a transformer 24 can be configured to convert the high voltage to a medium voltage or a low voltage, or to convert the medium voltage to a low voltage.

[0126] The majority of the induction heating devices 100 in the system 500 can be arranged in a production line (not designated / not shown) for the manufacture / processing of a metallic good, in particular a semi-finished product and / or a preliminary product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material, which, in addition to the induction heating devices 100, can also include treatment devices 40 for treating the metallic good (not shown) and wherein the metallic good (not shown) can be conveyed through the production line (not designated / not shown) in a preferred direction of movement 42. Depending on the position and rated power of an induction heating device 100, different positions within the production line (not designated / not shown) are conceivable for the respective resonant circuits 10.

[0127] In contrast, a system 500 comprising a plurality of induction heating devices 100, in particular comprising three induction heating devices 100, in Figure 2 a plurality of switching devices 30, in particular a number of switching devices 30 corresponding to the number of induction devices 100, in particular three switching devices 30, wherein the system has six resonant circuits 10 for heating a metallic good (not shown).

[0128] Accordingly, the system 500, comprising a plurality of induction heating devices 100, also comprises a plurality of power supply devices 20, in particular a number of power supply devices 20 corresponding to the number of induction devices 100, in particular three power supply devices 20.

[0129] According to the embodiment in Figure 2The switching devices 30 are each arranged in the area of ​​the alternating current transmission 29 of the induction heating device 100.

[0130] Each power supply device 20 has at least one disconnect switch 22 and at least one inverter 28, each inverter 28 being indirectly connected via a switching device 30 to at least two resonant circuits 10.

[0131] Depending on the design of an electrical power supply (not shown), a power supply device 20 may also include a transformer 24 and / or a rectifier 26, wherein a rectifier may be directly connected to an inverter 28 by means of a DC transmission 27 and / or a DC converter (not shown).

[0132] Each switching device 30 has at least two switches 32 which make a connection state between an inverter 28 and each resonant circuit 10 adjustable.

[0133] Many production lines (not shown) are installed for the manufacture and / or processing of different metallic goods (not shown), so a certain degree of flexibility in the technical equipment of the production line, particularly in the quantity and / or positioning of induction heating devices 100, is desirable / necessary. However, this also increases the investment costs for a production line. The induction heating device 100 proposed here has a switching device 30 within the power supply unit 20, which allows a plurality of resonant circuits to be supplied and / or operated alternately or intermittently, or, if the resonant circuits 10 are electrically configured identically, simultaneously, by a common power supply unit 20. This enables a reduction in the necessary investment costs compared to the prior art.

[0134] Accordingly, the number of resonant circuits 10 to which electrical energy can be supplied alternately and / or intermittently or simultaneously by the power supply unit 20 can be greater than the number of power supply units 20 by the induction heating device 100 proposed here.

[0135] A system 500 comprising a plurality of induction heating devices 100, in particular comprising three induction heating devices 100, in Figure 3 also has a plurality of switching devices 30, in particular a number of switching devices 30 corresponding to the number of induction devices 100, in particular three switching devices 30, wherein the system has seven resonant circuits 10 for heating a metallic material (not shown). In contrast to the embodiment according to Figure 2 The switching devices 30 are arranged here in the area of ​​the direct current transmission 27.

[0136] Accordingly, each resonant circuit 10 is connected to an inverter 28 by means of an AC transmission 29. This advantageously allows each individual resonant circuit 10 to be individually controlled and / or regulated via its individually assigned inverter 28.

[0137] Accordingly, the number of resonant circuits 10, to which electrical energy can be supplied alternately and / or intermittently or simultaneously by the power supply unit 20 and which corresponds to the number of inverters 28, can be greater than the number of rectifiers 26 and the number of disconnectors 22 and / or transformers 24.

[0138] A system 500 comprising a plurality of induction heating devices 100, in particular comprising two induction heating devices 100, in Figure 4also has a plurality of switching devices 30, in particular a number of switching devices 30 corresponding to the number of induction devices 100, in particular two switching devices 30, wherein the system has seven resonant circuits 10 for heating a metallic good (not shown).

[0139] A first induction heating device 100 is designed such that two resonant circuits 10 are arranged at the front end of a production line (not shown) and at the rear end of the production line. It is considered, among other things, that the resonant circuits 10 located at the front end can be operated in pairs, alternating or intermittently with the resonant circuits 10 located at the rear end. Reference symbol list

[0140] 10 Resonant circuit 20 Power supply unit 22 Disconnect switch 24 Transformer 26 Rectifier 27 DC transmission 28 Inverter 29 AC transmission 30 Switching device 32 Switch 40 Treatment unit 42 Direction of movement 100 Induction heating device 500 System

Claims

1. Induction heating device (100) for heating a metallic good, in particular a semi-finished product and / or a preliminary product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material, comprising: • a number of at least two resonant circuits (10), in particular three, four, five, six or more resonant circuits (10), for generating a magnetic field for heating the metallic good, and • a power supply device (20) for supplying the resonant circuits (10) with electrical energy, comprising: • a disconnect switch (22) for connecting the induction heating device (100) to an electrical power supply, and • at least one inverter (28), in particular two, three, four, five, six or more inverters (28), for converting a direct current into an alternating current for supplying energy to a resonant circuit (10), characterized by the fact thatthe power supply device (20) has a switching device (30), wherein the switching device (30) is configured to enable at least indirect energy coupling between the disconnect switch (22) and the resonant circuits (10), wherein the number of simultaneously energy-coupling resonant circuits (10) is smaller than the number of resonant circuits (10) of the induction heating device (100).

2. Induction heating device (100) according to claim 1, characterized by the fact that the disconnect switch (22) is set up for connecting the induction heating device (100) to a DC power supply.

3. Induction heating device (100) according to claim 1, characterized by the fact that• the disconnect switch (22) is provided for connecting the induction heating device (100) to an alternating current supply, and that • the power supply device (20) between the disconnect switch (22) and the at least one inverter (28) has at least one rectifier (26), in particular two, three, four, five, six or more rectifiers (26), for converting an alternating current into a direct current for the power supply of the at least one inverter (28).

4. Induction heating device (100) according to claim 3, characterized by the fact that the power supply unit (20) has a transformer (24) between the disconnect switch (22) and the at least one rectifier (26).

5. Induction heating device (100) according to one of the preceding claims, characterized by the fact thatthe power supply device (20) between the disconnect switch (22) and the at least one inverter (28), in particular between the at least one rectifier (26) and the at least one inverter (28), has a smoothing circuit.

6. Induction heating device (100) according to one of the preceding claims, characterized by the fact that the power supply device (20) between the disconnect switch (22) and the at least one inverter (28), in particular between the at least one rectifier (26) and the at least one inverter (28), includes a DC converter.

7. Induction heating device (100) according to one of the preceding claims, characterized by the fact thata switching device (30) is arranged between a rectifier (26) and at least two inverters (28), wherein the switching device (30) is configured to • establish an energy coupling between the rectifier (26) and exactly one inverter (28), and / or • establish an energy coupling between the rectifier (26) and a group of inverters (28), in particular an energy coupling between the rectifier (26) and a subset of the group of inverters (28).

8. Induction heating device (100) according to one of the preceding claims, characterized by the fact thata switching device (30) is arranged between an inverter (28) and at least two resonant circuits (10), wherein the switching device (30) is configured to: • establish an energy coupling between the inverter (28) and exactly one resonant circuit (10) for generating a magnetic field, and / or • establish an energy coupling between the inverter (28) and a group of resonant circuits (10) for generating a magnetic field each, in particular an energy coupling between the inverter (28) and a subset of the group of resonant circuits (10).

9. Induction heating device (100) according to one of the preceding claims, characterized by the fact that the induction heating device (100) is designed to be mechanically movable and / or is designed to be at least partially mechanically movable.

10. Induction heating device (100) according to one of the preceding claims, characterized by the fact thatthe power supply unit (20) is designed to be mechanically movable and / or is designed to be at least partially mechanically movable.

11. Induction heating device (100) according to one of the preceding claims, characterized by the fact that a resonant circuit (10) is designed for longitudinal field induction and / or transverse field induction.

12. Induction heating device (100) according to one of the preceding claims, characterized by the fact that an electrical connection between an inverter (28) and a resonant circuit (10) is formed by means of a fluid-cooled busbar, in particular a busbar equipped for internal cooling with a fluid.

13. System (500) comprising a plurality of induction heating devices (100) according to any one of claims 1 to 12.

14. Production line for the manufacture and / or processing of a metallic good, in particular a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material, comprising an induction heating device (100) according to any one of claims 1 to 12 and / or a system according to claim 13.

15. Method for operating an induction heating device (100) according to any one of claims 1 to 12, characterized by the fact that at least two resonant circuits (10) are operated alternately and / or intermittently at different points in a production line.

16. Use of an induction heating device (100) according to any one of claims 1 to 12 for the manufacture and / or processing of a metallic good, in particular a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material.

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