Adjustable induction heating system of transverse / longitudinal magnetic single machine

Abstract

The invention relates to an adjustable induction heating system of a transverse / longitudinal magnetic single machine. The adjustable induction heating system comprises an induction heating host power supply unit, an induction heating extension transformer unit, a transverse / longitudinal magnetic adjusting unit and an induction coil group unit, the induction heating host power supply unit and the induction heating extension transformer unit are connected in series; the induction coil assembly unit comprises an upper coil assembly and a lower coil assembly, the upper coil assembly is located on the upper surface of the to-be-heated plate strip, and the lower coil assembly is located on the lower surface of the to-be-heated plate strip; the inner coils of the upper coil group and the lower coil group are respectively connected with the induction heating extension transformer unit through the transverse / longitudinal magnetic adjusting unit; multiple groups of systems are sequentially arranged in the running direction of a to-be-heated plate strip. Mutual conversion from transverse magnetic flux induction heating to longitudinal magnetic flux induction heating can be achieved, the multiple sets of heating systems are arranged in the running direction of the plate strip, and the temperature uniformity in the width direction of the plate strip can be effectively improved through different combinations of transverse magnetic flux induction heating and longitudinal magnetic flux induction heating.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic induction heating, and in particular to a horizontal / longitudinal magnetic single-machine adjustable induction heating system. Background Art

[0002] Induction heating technology is widely used in heating of plates and strips due to its good controllability, high yield rate, and fast heating speed. Its working principle is to use the Faraday electromagnetic induction principle to generate an alternating magnetic field from an alternating current, so that an induced current, i.e., eddy current, is generated inside the heated workpiece, and the Joule heating effect of the eddy current is used to heat the workpiece.

[0003] Induction heating is usually divided into transverse flux induction heating and longitudinal flux induction heating. However, it is difficult to solve the problem of low temperature at the edge of the strip by using a single longitudinal flux induction heating method, while it is difficult to solve the problem of temperature uniformity in the width direction of the strip by using a single transverse flux induction heating method. Therefore, in order to both increase the overall temperature rise of the strip and reduce the temperature difference between the edge and the middle of the strip, it is urgent to develop a specific heating solution. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a single-machine adjustable transverse / longitudinal magnetic induction heating system, which adopts a circuit system in the form of a single-power supply and multiple-output transformers in series, and changes the connection mode of the induction coil and the transformer through the transverse / longitudinal magnetic adjustment unit, thereby changing the phase difference of the transformer output current, and then changing the current direction on the induction coil, thereby realizing the mutual conversion from a transverse magnetic flux induction heating device to a longitudinal magnetic flux induction heating device, and arranging a plurality of heating units in the running direction of the plate and strip, and improving the temperature uniformity in the width direction of the plate and strip through different combinations of transverse magnetic flux induction heating and longitudinal magnetic flux induction heating.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention proposes a single-machine adjustable transverse / longitudinal magnetic induction heating system, which comprises an induction heating main power supply unit, an induction heating extension transformer unit, a transverse / longitudinal magnetic adjustment unit, and an induction coil group unit; the induction heating main power supply unit and the induction heating extension transformer unit are connected in series; the induction coil group unit comprises an upper coil group and a lower coil group, the upper coil group is located on the upper surface of the plate strip to be heated, and the lower coil group is located on the lower surface of the plate strip to be heated; the inner coils of the upper coil group and the lower coil group are respectively connected to the induction heating extension transformer unit through the transverse / longitudinal magnetic adjustment unit; the system is arranged in multiple groups in sequence along the running direction of the plate strip to be heated.

[0007] Furthermore, the upper coil group and the lower coil group are single coils or double-layer coils or multi-layer coils.

[0008] Furthermore, the transverse / longitudinal magnetic regulation unit is a double-pole double-throw switch or a double relay, which realizes reverse control of current by changing the power supply mode of the induction heating extension transformer unit and the induction coil group unit.

[0009] Furthermore, the inner coils of the upper coil group and the lower coil group are respectively connected to the induction heating extension transformer unit. When the current phases of the upper coil group and the lower coil group are consistent, it is a transverse magnetic heating form. When the current phases of the upper coil group and the lower coil group differ by 180°, it is a longitudinal magnetic heating form.

[0010] Furthermore, when the upper coil group and the lower coil group are double-layer coils or multi-layer coils, the structural form of each layer of coils can be changed to achieve superposition of different magnetic field forms.

[0011] Furthermore, the current phase difference between the upper coil group and the lower coil group is adjusted by a frequency converter or a digital signal processor or an adjustable capacitor or inductor, so that the current phase difference between the upper coil group and the lower coil group is adjustable within the range of 0° to 180°.

[0012] Furthermore, the system is arranged in multiple groups in sequence along the running direction of the strip to be heated, and the arrangement methods include full transverse magnetic arrangement, full longitudinal magnetic arrangement, alternating transverse / longitudinal magnetic arrangement, and any group is arranged in the form of transverse / longitudinal magnetic heating.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention changes the connection mode between the induction coil and the transformer through the transverse / longitudinal magnetic adjustment unit, thereby realizing the mutual conversion between transverse magnetic flux induction heating and longitudinal magnetic flux induction heating, which can meet the heating requirements of different plates and strips and has a wider range of applications.

[0015] 2. The present invention controls the temperature of the moving strip in different regions through different combinations of transverse magnetic flux and longitudinal magnetic flux of multiple heating units, thereby effectively improving the temperature uniformity in the width direction of the strip.

[0016] 3. The present invention has a simple structure and has different heating methods for different plates and strips, which effectively improves energy utilization and saves production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the working principle of a double-pole double-throw switch (DPDT);

[0019] Figures 3 to 5 This is a schematic diagram of the coil current direction, magnetic flux lines, eddy current direction on the strip surface, and temperature results of the simulation in transverse flux induction heating;

[0020] Figures 6 to 9 It is a schematic diagram of the coil current direction, magnetic flux lines, eddy current direction, eddy current direction on the strip surface, eddy current direction on the cross section along the strip width direction, and temperature results of the simulation in the longitudinal flux induction heating;

[0021] Fig.10 and Fig.11 Schematic diagram of the combination of different numbers of coils and induction heating extension transformer units;

[0022] Fig.12 and Fig.13 Schematic diagram of the current direction on the coil, the magnetic flux lines generated by the coil, and the eddy current generated on the cross section of the strip for the two induction heating methods after increasing the number of coils;

[0023] Fig.14 and Fig.15 Schematic diagram of different structural forms (single-layer coil and double-layer coil) of the upper coil group and the lower coil group;

[0024] Figures 16 to 18 It is a schematic diagram of the traditional longitudinal magnetic heating structure and its coil current direction, magnetic flux lines, eddy current direction and eddy current direction on the strip surface;

[0025] Figures 19 to 21 Schematic diagram of different combinations of adjustable induction heating systems along the width direction of the strip;

[0026] Fig. 22 Schematic diagram of the respective structural forms of the upper coil group and the lower coil group (double coils and different structural combinations of double coils).

[0027] Among them, the figure markings are: 1-induction heating main power supply unit; 2-induction heating extension transformer unit; 3-horizontal / longitudinal magnetic adjustment unit; 4-induction coil group unit; 5-plate strip; 6-upper coil group; 7-lower coil group; 8-spiral coil. DETAILED DESCRIPTION

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] It should be noted that, in the description of the present invention, the terms "up", "down", "top", "bottom", "one side", "the other side", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device or element must have a specific orientation, be constructed and operated in a specific orientation.

[0030] See attached Figure 1-22 , gives the specific structure of an embodiment of a horizontal / longitudinal magnetic single-machine adjustable induction heating system proposed by the present invention. The induction heating system includes an induction heating main power supply unit 1, an induction heating extension transformer unit 2, a horizontal / longitudinal magnetic adjustment unit 3, and an induction coil group unit 4; the induction heating main power supply unit 1 and the induction heating extension transformer unit 2 are connected in series; the induction coil group unit 4 includes an upper coil group 6 and a lower coil group 7, the upper coil group 6 is located on the upper surface of the plate strip 5 to be heated, and the lower coil group 7 is located on the lower surface of the plate strip 5 to be heated; the inner coils of the upper coil group 6 and the lower coil group 7 are respectively connected to the induction heating extension transformer unit 2 through the horizontal / longitudinal magnetic adjustment unit 3.

[0031] The heating system is arranged in multiple groups in sequence along the running direction of the plate strip 5 to be heated, including full transverse magnetic arrangement, full longitudinal magnetic arrangement, transverse / longitudinal magnetic alternating arrangement, and any group is arranged in the form of transverse / longitudinal magnetic heating, which can be applied to uniform heating in the width direction of plates and strips of different thicknesses and widths; through different combinations, the process control ability of induction heating of the moving plate strip 5 can be enhanced, and temperature zoning control can be performed according to different heating requirements in the width direction of the plate strip 5, thereby improving the temperature uniformity in the width direction of the plate strip 5. By adjusting the power supply strategy of each group of heating systems and changing the transverse / longitudinal magnetic heating form of each group, the characteristic heating effect can be achieved, which can greatly reduce the layout requirements of the induction heating system and reduce the production line cost.

[0032] The upper coil group 6 and the lower coil group 7 are in any form such as a single coil or a double-layer coil or a multi-layer coil, and the structure of the coil can be changed, including the coil diameter, winding method, coil shape, etc. Among them, when the upper coil group and the lower coil group are double-layer coils or multi-layer coils, the structure of each layer of coils can be changed to achieve superposition of different magnetic field forms. By increasing the number of induction coils, the magnetic field superposition effect of the transverse magnetic flux and the longitudinal magnetic flux can be enhanced, and the temperature rise capacity of the induction heating system is improved under the same excitation parameter input, thereby improving energy utilization.

[0033] In the upper coil group 6 and the lower coil group 7, each layer of coils can be connected to the induction heating main power supply unit 1 through a transverse / longitudinal magnetic adjustment unit 3 and an induction heating extension transformer unit 2. Each layer of coils can also be connected in parallel to the induction heating main power supply unit 1 through a transverse / longitudinal magnetic adjustment unit 3 and an induction heating extension transformer unit 2.

[0034] The transverse / longitudinal magnetic regulation unit 3 can use a double-pole double-throw switch (DPDT) or a double relay to switch the system, and realize the reverse control of the current by changing the power supply mode of the induction heating extension transformer unit 2 and the induction coil unit. In this embodiment, the transverse / longitudinal magnetic regulation unit 3 uses a double-pole double-throw switch (DPDT), such as Figure 2 As shown, the double-pole double-throw switch (DPDT) realizes current reverse control by changing the energization mode of the induction heating extension transformer unit 2 and the induction coil group unit 4.

[0035] The inner coils of the upper coil group 6 and the lower coil group 7 are respectively connected to the induction heating extension transformer unit 2. When the current phases of the upper coil group 6 and the lower coil group 7 are consistent, it is a transverse magnetic heating form, and when the current phases of the upper coil group and the lower coil group differ by 180°, it is a longitudinal magnetic heating form. The mutual conversion of transverse magnetic flux and longitudinal magnetic flux is realized, and flexible regulation can be achieved according to the heating requirements of different plates and strips 5, which broadens the scope of use of the induction heating system. The current phase difference between the upper coil group 6 and the lower coil group 7 can be adjusted by a frequency converter or a digital signal processor or an adjustable capacitor or inductor, so that the current phase difference between the upper coil group 6 and the lower coil group 7 can be adjusted within the range of 0° to 180°.

[0036] Different from the traditional longitudinal magnetic heating form formed by spiral coils, the longitudinal magnetic heating form in the present invention adapts to the heating of plates and strips of different widths by the mutual transverse displacement of the upper coil group 6 and the lower coil group 7 along the plate width direction. The heating method of the upper coil group 6 and the lower coil group 7 can effectively reduce the temperature gradient problem caused by a single spiral coil. This uniformity helps to improve the overall performance of the workpiece, especially in processes such as heat treatment and welding.

[0037] The working principle of the present invention is that the strip 5 moves between the upper coil group 6 and the lower coil group 7, and the transverse / longitudinal magnetic type of the induction heating group unit is changed by the transverse / longitudinal magnetic adjustment unit 3. When the upper coil group 6 and the lower coil group 7 are connected with the same current direction, the magnetic field direction generated is the same, and the magnetic field lines pass through the strip 5 vertically to form a transverse magnetic flux; when the upper coil group 6 and the lower coil group 7 are connected with the opposite current direction, the magnetic field directions generated are opposite, the two magnetic fields repel each other, and the magnetic field lines are parallel to the strip surface. According to Faraday's law of electromagnetic induction, an induced electromotive force will be generated inside the strip 5, thereby generating an induced current, and the induced current forms a closed loop. Due to the resistance of the strip 5, its temperature rises rapidly, thereby achieving heating of the strip 5.

[0038] Matters not covered in the present invention are all known technologies.

[0039] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A single-machine adjustable transverse / longitudinal magnetic induction heating system, characterized in that: The system includes an induction heating main power supply unit, an induction heating extension transformer unit, a transverse / longitudinal magnetic regulation unit, and an induction coil group unit; the induction heating main power supply unit and the induction heating extension transformer unit are connected in series; the induction coil group unit includes an upper coil group and a lower coil group, the upper coil group is located on the upper surface of the plate strip to be heated, and the lower coil group is located on the lower surface of the plate strip to be heated; the inner coils of the upper coil group and the lower coil group are respectively connected to the induction heating extension transformer unit through the transverse / longitudinal magnetic regulation unit; the system is arranged in multiple groups in sequence along the running direction of the plate strip to be heated.

2. According to claim 1, a single-machine adjustable transverse / longitudinal magnetic induction heating system is characterized in that: The upper coil group and the lower coil group are single coils or double-layer coils or multi-layer coils.

3. According to claim 2, a single-machine adjustable transverse / longitudinal magnetic induction heating system is characterized in that: The transverse / longitudinal magnetic regulation unit is a double-pole double-throw switch or a double relay, which realizes reverse control of current by changing the power supply mode of the induction heating extension transformer unit and the induction coil group unit.

4. The horizontal / longitudinal magnetic single-machine adjustable induction heating system according to claim 2, characterized in that: The inner coils of the upper coil group and the lower coil group are respectively connected to the induction heating extension transformer unit. When the current phases of the upper coil group and the lower coil group are consistent, it is a transverse magnetic heating form. When the current phases of the upper coil group and the lower coil group differ by 180°, it is a longitudinal magnetic heating form.

5. The horizontal / vertical magnetic single-machine adjustable induction heating system according to claim 2 is characterized in that: When the upper coil group and the lower coil group are double-layer coils or multi-layer coils, the structural form of each layer of coils can be changed to achieve superposition of different magnetic field forms.

6. The horizontal / longitudinal magnetic single-machine adjustable induction heating system according to claim 4, characterized in that: The current phase difference between the upper coil group and the lower coil group is adjusted by a frequency converter or a digital signal processor or an adjustable capacitor or inductor, so that the current phase difference between the upper coil group and the lower coil group is adjustable within the range of 0° to 180°.

7. The horizontal / longitudinal magnetic single-machine adjustable induction heating system according to claim 4, characterized in that: The system is arranged in multiple groups in sequence along the running direction of the strip to be heated, and the arrangement modes include full transverse magnetic arrangement, full longitudinal magnetic arrangement, transverse / longitudinal magnetic alternating arrangement, and any group is arranged in the form of transverse / longitudinal magnetic heating.

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