A powerful electromagnetic oven wire coil

Abstract

The application discloses a kind of strong electromagnetic oven wire coil, belong to electromagnetic oven technical field.The electromagnetic oven wire coil includes wire coil support and coil, the coil is wound in two layers, surface layer is wound 9 to 14 circles and covers inner ring area, bottom layer is wound 11 to 16 circles and covers entire radial area, so that inner ring forms double-layer winding, outer ring forms single-layer winding, and winding pitch is same.The application significantly enhances the magnetic field intensity of central area by non-uniform magnetic field design, improves heating speed, and simultaneously compensates the heat dissipation difference between the center and edge of pot bottom from the source of heat generation through the synergistic effect of winding method and magnetic circuit structure, improves heating uniformity.According to GB 21456 test by third-party testing organization, the thermal efficiency reaches 91% when heating 2kg water from 15℃ to 75℃ under 2500W power, exceeding national level energy efficiency standard, achieving unexpected technical effect.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic heating technology, and specifically relates to an induction cooker coil. Background Technology

[0002] Induction cookers generate a high-frequency alternating magnetic field through a coil, causing eddy currents in the bottom of the pot and thus heating it. Current induction cooker coils generally use a uniform winding method, meaning the number of turns in the inner and outer coils is basically the same. The drawback of this method is that the heating rate at the center of the pot bottom is limited by the overall turn density, making it difficult to further increase the heating speed.

[0003] Because the bottom of the pot is a continuous heat conductor, the heat dissipation conditions in the central area are much worse than those at the edges. When operating at high power, heat accumulates rapidly in the central area due to its small surface area, while heat is quickly lost from the edges due to their large surface area. This results in a problem where the central temperature soars while the edge temperature remains relatively low, leading to poor heating uniformity.

[0004] Single-layer and double-layer windings have long been used in motors, transformers, and other fields, but their application purposes and working environments are fundamentally different from those of induction cooker coils. In the field of motors, single and double-layer windings are used to adjust the number of pole pairs and magnetic field distribution of the windings, with operating frequencies typically ranging from 50Hz to 400Hz. In the field of transformers, single and double-layer windings are used to adjust the voltage ratio and impedance matching, with operating frequencies typically at the power frequency of 50Hz or intermediate frequencies of several kilohertz. However, induction cooker coils operate at frequencies as high as 20kHz to 40kHz, with power ratings reaching several kilowatts, and require efficient energy transfer to the bottom of the cookware under a high-frequency alternating magnetic field. This high-frequency, high-power working environment differs significantly from that of motors and transformers, and those skilled in the art would not naturally think of transferring the winding methods of motors or transformers to induction cooker coils.

[0005] Furthermore, a long-standing technical bias exists in this field: induction cookers require uniform heating, therefore the coil should also be wound uniformly. This bias has led to the long-standing adherence to uniform winding schemes, with no one ever attempting a non-uniform winding method using two layers, forming an inner double-layer and an outer single-layer ring. This invention breaks this technical bias by actively designing a non-uniform magnetic field distribution to compensate for heat generation at its source. The inner double-layer winding provides efficient energy absorption in the central area of ​​the pot bottom, ensuring heating speed; the outer single-layer winding, combined with the overlapping and gap structure of the magnetic ring and magnetic strip, efficiently guides magnetic lines of force into the central area while actively directing some magnetic lines of force to the edge of the pot bottom through the gaps. This winding method, in synergy with the magnetic circuit structure, compensates for the difference in heat dissipation between the center and edge of the pot bottom at the source of heat generation—the poor heat dissipation in the central area optimizes its energy absorption, preventing excessive energy accumulation; the rapid heat dissipation in the edge area strengthens its magnetic field supply, compensating for heat loss and achieving a better balance between heat generation and dissipation.

[0006] Currently, the thermal efficiency of similar induction cooker coils on the market is typically between 85% and 88%. No existing technology has disclosed or implied that combining a two-layer winding method (forming a double inner ring and a single outer ring) with the aforementioned magnetic circuit structure in an induction cooker coil could achieve a thermal efficiency exceeding 90%. Therefore, the technical solution of this invention is not a conventional optimization easily conceived by those skilled in the art, but rather an innovative solution that has undergone extensive experimental verification and produced unexpected technical effects. Summary of the Invention

[0007] The technical problem to be solved by the present invention is that the existing uniform winding method cannot take into account both heating speed and heating uniformity, and the thermal efficiency is difficult to exceed 90%.

[0008] To solve the above-mentioned technical problems, the present invention provides an induction cooker coil, including a coil support and a coil wound on the coil support. The coil is wound in two layers, including a top layer and a bottom layer. The top layer is wound with 9 to 14 turns, and the bottom layer is wound with 11 to 16 turns. The top layer covers the inner ring area, and the bottom layer covers the entire radial area, so that the inner ring area superimposed by the top layer and the bottom layer forms a double-layer winding, and the outer ring area covered by the bottom layer alone forms a single-layer winding. The winding spacing of the top layer and the bottom layer is the same.

[0009] The present invention also provides a method for improving the heating speed of an induction cooker, wherein the coil is wound in two layers, with the surface layer having 9 to 14 turns and the bottom layer having 11 to 16 turns, while maintaining the same winding spacing, so that the surface layer covers the inner ring area and the bottom layer covers the entire radial area, thereby forming a double-layer winding in the inner ring area and a single-layer winding in the outer ring area, so that the number of turns per unit area in the inner ring area is higher than that in the outer ring area.

[0010] The beneficial effects of this invention are as follows: the inner ring double-layer winding significantly enhances the magnetic field strength in the central region, greatly increasing the heating speed; the outer ring single-layer winding, combined with the magnetic circuit structure, achieves a significant improvement in overall heating uniformity—the overlapping structure of the magnetic ring and magnetic strip efficiently guides magnetic lines of force into the central region, while the gap between the overlapping surfaces actively guides some magnetic lines of force to the edge of the pot bottom. The winding method and the magnetic circuit structure work synergistically to compensate for the heat dissipation difference between the center and the edge of the pot bottom from the source of heat generation; the winding spacing of the surface layer and the bottom layer is the same, the process is simple, and it is easy to automate production; this invention is the first to introduce the winding method of two layers, forming an inner ring double-layer and an outer ring single-layer, into the field of induction cooker coils, breaking the long-standing technical prejudice of "uniform winding" in this field.

[0011] It should be noted that the aforementioned 91% thermal efficiency is the combined effect of the technical features claimed in this invention and other optimized designs of the induction cooker coil (including overlapping and gapped magnetic circuit structure, material matching, forward and reverse winding wire, etc.), and is not solely contributed by the single technical feature of the winding method. However, the technical features claimed in this invention, when applied alone without being combined with other optimized designs, can produce independent beneficial effects: by using a winding method of "two-layer winding, double-layer inner ring and single-layer outer ring," while keeping other structures as traditional solutions (homogeneous materials, separate magnetic circuits, traditional enameled wire), the thermal efficiency can be increased from 86.2% to 87.8%, an increase of approximately 1.6 percentage points, while simultaneously improving heating uniformity. This independent effect is unrelated to other technical features of this invention, fully demonstrating that the winding method of this invention is inventive in itself and does not necessarily rely on other technical features to achieve its technical effect.

[0012] According to the national standard GB 21456, the induction cooker coil of this invention, when heated from 15°C to 75°C at 2500W, achieved a thermal efficiency of 91%, exceeding the national first-class energy efficiency standard. The thermal efficiency of similar products on the market is usually between 85% and 88%. This invention improves upon existing technologies by about 3 to 6 percentage points, achieving unexpected technical results. Attached Figure Description

[0013] Figure 1 This is a top view of the overall structure of the induction cooker coil according to Embodiment 1 of the present invention.

[0014] Figure 2 yes Figure 1 AA sectional view.

[0015] Figure 3 This is a comparison chart of the heating rates of Embodiment 1 of the present invention and the traditional uniform winding scheme.

[0016] Figure 4 Coil cross-section Figure 5 This is a diagram of the magnetic circuit structure of an induction cooker coil. In the diagram: 1-coil support, 2-coil, 3-inner double-layer winding area, 4-outer single-layer winding area. Detailed Implementation

[0017] Example 1 (Optimal solution - 11 top coats, 13 bottom coats, 2500W) Reference Figure 1 and Figure 2 and Figure 4 and Figure 5This embodiment provides a coil for use in a 2500W induction cooker. The coil includes a coil support (1) and a coil (2) wound on the coil support (1). The coil (2) is made of forward and reverse wound wire. The coil (2) is wound in two layers, including a top layer and a bottom layer. The top layer is wound 11 turns, covering the inner ring area; the bottom layer is wound 13 turns, covering the entire radial area. The top layer and the bottom layer are superimposed in the inner ring area to form an inner ring double-layer winding (3), and the bottom layer is separately formed in the outer ring area to form an outer ring single-layer winding (4). The winding spacing of each turn of the top layer and the bottom layer is exactly the same. The actual number of turns in the inner ring double-layer area is the superposition of the top layer and the bottom layer in this area, so that the number of turns per unit area in the inner ring area is higher than that in the outer ring area.

[0018] This embodiment also includes seven manganese-zinc ferrite magnetic strips (6) fixed to the bottom of the support and an iron powder core magnetic ring (7) disposed above the magnetic strips (6). The iron powder core magnetic ring (7) has distributed micro-air gaps inside, which have excellent anti-saturation ability. The magnetic ring (7) and the magnetic strips (6) overlap in the vertical direction, with an overlap of 0.45 cm. A gap (8) with a thickness of 1 mm is left between the overlapping surfaces of the magnetic ring (7) and the magnetic strips (6).

[0019] Tests showed that the induction cooker coil in this embodiment, at a power of 2500W, achieved a thermal efficiency of 91% when heating 2kg of water from 15℃ to 75℃ according to the national standard GB 21456, far exceeding the national first-class energy efficiency standard. The test results have been officially reported by a qualified third-party testing institution (report number: CEL-A-20260703-069817).

[0020] Reference Figure 3 The heating rate comparison curve of this embodiment with the traditional uniform winding scheme intuitively demonstrates the significant effect of the present invention.

[0021] Example 2 (2200W verification) With the same structure as Example 1, 2 kg of water was heated from 15°C to 75°C at a power of 2200W. According to GB 21456, the thermal efficiency reached 90.2%, which also exceeded the national first-class energy efficiency standard.

[0022] Example 3 (Verification of the lower limit of the number of top layer layers - 9 layers for the top layer and 11 layers for the bottom layer) The difference from Embodiment 1 is that in this embodiment, the surface layer has 9 turns and the bottom layer has 11 turns. Testing showed that the heating speed and thermal efficiency of this embodiment are still superior to the traditional uniform winding scheme, proving that the technical solution remains effective even with the minimum number of turns specified in the claims.

[0023] Example 4 (Verification of the upper limit of the number of top layer layers - 14 top layer layers, 16 bottom layer layers) The difference from Embodiment 1 is that in this embodiment, the surface layer has 14 turns and the bottom layer has 16 turns. Testing showed that the heating speed improvement in this embodiment is similar to that in Embodiment 1, proving that the technical solution remains effective even at the maximum number of turns specified in the claims.

[0024] Example 5 (Verification of the midpoint of the number of top layer layers - 12 top layer layers, 14 bottom layer layers) The difference from Embodiment 1 is that in this embodiment, the surface layer has 12 turns and the bottom layer has 14 turns. Testing showed that the heating rate and thermal efficiency of this embodiment are between those of Embodiment 1 and Embodiment 3, demonstrating that the technical solution can produce beneficial effects within the entire range of the number of turns defined in the claims.

[0025] Comparative Example 1 (Traditional Equal Winding Scheme) In contrast, under identical test conditions (2500W power, same motherboard, same cookware, 2kg water), the induction cooker coil using a traditional uniform winding scheme (both inner and outer rings are single-layer windings, with the same total number of turns as in Example 1) only achieved a thermal efficiency of 86.2% when heating 2kg of water from 15°C to 75°C. Compared to 86.2%, Example 1's 91% represents an improvement of approximately 4.8 percentage points in thermal efficiency. This improvement far exceeds the conventional expectations of those skilled in the art regarding winding optimization, fully demonstrating that the non-uniform winding method of this invention produces unexpected technical effects.

[0026] Comparative Example 2 (Scheme with more surface layer layers than bottom layer) In contrast, under identical testing conditions, the induction cooker coil with 13 turns on the surface and 11 turns on the bottom layer had a thermal efficiency of 87.5%, which is still far lower than the 91% of Example 1. This shows that simply changing the number of turns on the surface and bottom layers does not necessarily produce a 91% thermal efficiency. The specific turn distribution direction of this invention is the optimal solution verified by a large number of experiments, and is not a simple conventional choice.

[0027] Comparative Example 3 (both inner and outer layers are double-layered) In contrast, under the exact same test conditions, the induction cooker coil with a double-layer winding scheme (13 turns on the surface layer, 13 turns on the bottom layer, and double-layer winding in both the inner and outer ring areas, with the total number of turns the same as in Example 1) had a thermal efficiency of 89.5%, which is higher than the 86.2% of the traditional equal winding scheme, but still lower than the 91% of Example 1.

[0028] Test results also showed that the temperature at the center of the pot bottom in this comparative example rose faster, and the temperature difference between the center and the edge was greater than in Example 1. The heating uniformity was actually worse than the "double-layer inner ring, single-layer outer ring" scheme of this invention. This indicates that simply increasing the number of winding layers does not necessarily improve thermal efficiency and uniformity. This invention intentionally designs the outer ring as a single-layer winding precisely to actively suppress the magnetic field strength in the edge region, preventing overheating at the edge. Simultaneously, through the synergistic effect of the magnetic circuit structure, more magnetic lines of force are guided to the edge, compensating for heat loss. This asymmetric design of "double-layer inner ring, single-layer outer ring" is the optimal solution verified through extensive experiments, and is not a conventional choice easily conceived by those skilled in the art.

[0029] Comparative Example 4 (Inner Ring Turns Density Reduction Scheme - Expected Violation Experiment) In contrast, under identical testing conditions, a coil with a lower inner ring turn density than in Example 1 was fabricated, with 7 turns on the surface layer and 13 turns on the bottom layer, covering the same radial area. As would be conventionally expected by those skilled in the art, a reduction in the inner ring turn density should improve heating uniformity because the difference in magnetic field strength between the inner and outer rings is reduced.

[0030] However, actual test results showed that the heating uniformity of this comparative example was worse than that of Example 1, with a greater temperature difference between the center and edge of the pot bottom, and the thermal efficiency dropped to 84.3%, even lower than the traditional uniform winding scheme. This result contradicts the conventional expectations of those skilled in the art based on common knowledge, further proving that the specific winding method and its turn density ratio range of the present invention are not simple conventional choices, but rather an innovative solution that has been verified through extensive experiments and produced unexpected technical effects.

[0031] Comparative Example 5 (Independent Effect Verification – Only the winding method was changed, while other structures remained the traditional scheme) In contrast, under exactly the same test conditions (2500W power, same motherboard, same cookware, 2kg water), an induction cooker coil was made, only the winding method was changed to the scheme of this invention (the coil uses traditional enameled wire, wound in two layers, the surface layer is wound with 11 turns, covering the inner ring area, and the bottom layer is wound with 13 turns, covering the entire radial area, forming a double inner ring and a single outer ring), but other structures remain the traditional scheme (the magnetic strip and magnetic ring are both manganese zinc ferrite, separate, non-overlapping and gapless).

[0032] Test results show that the thermal efficiency of this comparative example is 87.8%, which is about 1.6 percentage points higher than the 86.2% of the traditional uniform winding scheme (both inner and outer rings are single-layer windings, and other structures are the same). At the same time, the heating uniformity is improved.

[0033] This result demonstrates that the winding method claimed in this invention, when applied alone without being combined with other optimized designs (magnetic circuit overlap and gap, material matching, and forward and reverse winding), can produce independent beneficial effects—improving thermal efficiency and heating uniformity. This independent effect is unrelated to other technical features of this invention, fully proving that the winding method of this invention is inventive in itself and does not necessarily rely on other technical features to achieve its technical effects.

[0034] Proof of a Double Breakthrough The test results of Comparative Examples 1 and 3 jointly demonstrate a long-standing technical bias in the field: traditional uniform winding schemes have limited thermal efficiency, and the uniformity of the full double-layer scheme deteriorates. However, the solution of this invention—a non-uniform winding method with an inner double-layer and an outer single-layer—simultaneously overcomes both the thermal efficiency bottleneck and uniformity limitation, achieving a high thermal efficiency of 91% while significantly improving heating uniformity. This achieves a dual technical objective that those skilled in the art have long been unable to simultaneously achieve. This dual breakthrough effect is something that those skilled in the art could not have foreseen from the prior art, further demonstrating the inventiveness of this invention.

[0035] Proof of independent creativity The test results of Comparative Example 5 alone demonstrate the independent inventiveness of the winding method of this invention: even without any other optimized design, applying the "two-layer winding, double-layer inner ring and single-layer outer ring" winding method of this invention alone can increase the thermal efficiency from 86.2% to 87.8%, an increase of approximately 1.6 percentage points, based on traditional homogeneous materials, split magnetic circuit structures, and traditional enameled wires, while simultaneously improving heating uniformity. This independent effect does not depend on other technical features of this invention, fully demonstrating that the winding method of this invention itself possesses significant inventiveness.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An induction cooker coil, comprising a coil support and a coil wound on the coil support, characterized in that: The coil is wound in two layers, including a surface layer and a bottom layer. The surface layer is wound with 9 to 14 turns, and the bottom layer is wound with 11 to 16 turns. The surface layer covers the inner ring area, and the bottom layer covers the entire radial area, so that the inner ring area superimposed by the surface layer and the bottom layer forms a double-layer winding, and the outer ring area covered by the bottom layer alone forms a single-layer winding, and the winding spacing of the surface layer and the bottom layer is the same.

2. A method for increasing the heating speed of an induction cooker, characterized in that: The coil is wound in two layers: the top layer has 9 to 14 turns and the bottom layer has 11 to 16 turns, with the winding spacing being the same. This allows the top layer to cover the inner ring area and the bottom layer to cover the entire radial area, thus forming a double-layer winding in the inner ring area and a single-layer winding in the outer ring area. This results in a higher number of turns per unit area in the inner ring area compared to the outer ring area.

3. The induction cooker coil according to claim 1, characterized in that: The top layer is wound 11 times, and the bottom layer is wound 13 times.

4. The induction cooker coil according to claim 1, characterized in that: It also includes a magnetic strip and a magnetic ring, wherein the magnetic ring is located above the magnetic strip and overlaps the magnetic strip in the vertical direction, with a gap between the overlapping surfaces.

5. The induction cooker coil according to claim 4, characterized in that: The magnetic permeability of the magnetic ring is lower than that of the magnetic strip. The magnetic strip is made of manganese-zinc ferrite, and the magnetic ring is made of iron powder core.

6. The induction cooker coil according to claim 1, characterized in that: The induction cooker coil, within a power range of 2200W to 2500W, heats 2kg of water from 15℃ to 75℃. According to GB 21456 testing, the thermal efficiency reaches over 90%, with a thermal efficiency of 91% at 2500W power.

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