Induction heating conditioner

Abstract

To provide an induction heating cooker that can reduce the number of relay switching cycles. [Solution] The induction heating cooker according to the present disclosure comprises a top plate on which an object to be heated is placed, a coil unit including a first coil and a second coil disposed below the top plate, a controller for controlling the coil unit, and a first relay for switching the connection between the controller and the first coil ON / OFF, wherein the second coil is electrically connected to the controller, and the controller supplies a detection current to the second coil for detecting the object to be heated while the connection between the controller and the first coil is turned OFF by the first relay, and detects whether or not the object to be heated is placed in the heating region including the second coil based on the detection current flowing through the second coil.

Description

Technical Field

[0001] The present disclosure relates to an induction heating cooker.

Background Art

[0002] Patent Document 1 discloses an induction heating device including a top plate, a plurality of heating coils provided below the top plate, a drive unit that supplies high-frequency power to the plurality of heating coils, an electrical signal detection unit that detects an electrical signal related to an element included in the drive unit, and a control unit that inputs the detected electrical signal and controls the drive unit. Further, the induction heating device described in Patent Document 1 further includes a plurality of relays which are switching units that are controlled by the control unit to connect or disconnect between each of the plurality of heating coils and the drive unit, and when a detection current is supplied, the control unit controls the plurality of relays so as to connect all of the plurality of heating coils to the drive unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the device described in Patent Document 1, there is still room for improvement in terms of reducing the number of relay switching operations.

[0005] Therefore, an object of the present disclosure is to solve the above problems and provide an induction heating cooker capable of reducing the number of relay switching operations.

Means for Solving the Problems

[0006] An induction heating cooker according to one aspect of the present disclosure comprises a top plate on which an object to be heated is placed, a coil unit including a first coil and a second coil disposed below the top plate, a controller for controlling the coil unit, and a first relay for switching the connection between the controller and the first coil ON / OFF, wherein the second coil is electrically connected to the controller, and the controller supplies a detection current to the second coil for detecting the object to be heated while the connection between the controller and the first coil is turned OFF by the first relay, and detects whether or not the object to be heated is placed in the heating region including the second coil based on the detection current flowing through the second coil. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an induction heating cooker that can reduce the number of relay switching cycles. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of an example of an induction heating cooker according to Embodiment 1 of the present disclosure. [Figure 2] This is a schematic plan view showing the schematic configuration of the coil unit of the induction heating cooker according to Embodiment 1 of the present disclosure. [Figure 3] A schematic block diagram showing an example of the main configuration of the induction heating cooker according to Embodiment 1 of this disclosure. [Figure 4] This flowchart shows an example of the operation of the induction heating cooker according to Embodiment 1 of this disclosure. [Figure 5] This is a schematic plan view showing the general configuration of the induction heating cooker according to Embodiment 2 of the present disclosure. [Figure 6] This is a schematic plan view showing the schematic configuration of the coil unit of the induction heating cooker according to Embodiment 2 of the present disclosure. [Figure 7] A schematic block diagram showing an example of the main configuration of the induction heating cooker according to Embodiment 2 of this disclosure. [Figure 8]This flowchart shows an example of the operation of the induction heating cooker according to Embodiment 2 of this disclosure. [Figure 9] This is a schematic plan view showing another example of the position of the second coil relative to the top plate. [Figure 10] This is a schematic plan view showing another example of the position of the second coil relative to the top plate. [Figure 11] This is a schematic plan view showing another example of the position of the second coil relative to the top plate. [Figure 12] This is a schematic diagram of an induction cooker according to Modification 1. [Figure 13] This is a schematic diagram of a modified example 2 of an induction heating cooker. [Modes for carrying out the invention]

[0009] (Background leading to this disclosure) In induction cookers, the object to be heated, placed on the top plate, is detected by supplying a detection current to multiple coils. Such induction cookers sequentially supply the detection current to multiple coils using multiple relays. For example, an induction cooker switches the coil to which the detection current is supplied by switching multiple relays, thereby supplying detection current to all coils.

[0010] However, in such a configuration, the number of times multiple relays are switched tends to increase, resulting in frequent relay switching noises, which can be unpleasant for the user. Furthermore, because detection current is supplied sequentially to all coils to detect the object being heated, the detection time may be longer.

[0011] Therefore, the present inventors investigated the configuration of an induction heating cooker that can reduce the number of relay switching cycles, and have arrived at this disclosure.

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. Note that the following description is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses. Further, the drawings are schematic, and the ratios of each dimension etc. do not necessarily match the actual ones.

[0013] In this specification, terms such as "first" and "second" are used only for the purpose of explanation and should not be understood as indicating or implying relative importance or the order of technical features. The features limited to "first" and "second" explicitly or implicitly include one or more of the said features.

[0014] (Embodiment 1) [Overall Configuration] FIG. 1 is a schematic perspective view of an example of an induction heating cooker 1 according to Embodiment 1 of the present disclosure. The X - Y - Z coordinate system shown in the figure is for assisting in understanding the invention and does not limit the invention. The X - axis direction indicates the left - right direction, the Y - axis direction indicates the front - rear direction, and the Z - axis direction indicates the vertical direction.

[0015] As shown in FIG. 1, the induction heating cooker 1 is a cooker that inductively heats a heating object C that houses a cooking target T. In this embodiment, the induction heating cooker 1 is a built - in type cooker. Further, the heating object C is a cooking container, for example, a pot. Note that the heating object C is not limited to a cooking container and may be any object that can be inductively heated. The cooking target T may be a liquid or food ingredients.

[0016] As shown in FIG. 1, the induction heating cooker 1 includes a top plate 2, a housing 3, a plurality of coil units 4, a controller 5, and an operation device 6.

[0017] The top plate 2 is a plate on which the heating object C is placed. The top plate 2 is made of, for example, heat - resistant glass. The top plate 2 has, for example, a rectangular shape with a longitudinal direction in the left - right direction (X - axis direction) in plan view.

[0018] In this specification, "plan view" means viewing from the vertical direction, i.e., the Z-axis direction.

[0019] The enclosure 3 is attached to the top plate 2. The enclosure 3 is equipped with multiple coil units 4, a controller 5, and an operating device 6.

[0020] The coil unit 4 is positioned below the top plate 2 and induces heating of the object C placed on the top plate 2. In other words, the coil unit 4 functions as an induction heating coil unit.

[0021] Controller 5 is a device that controls the operation of the induction cooker 1. Controller 5 includes, for example, a memory that stores a program and a processing circuit corresponding to a processor such as a CPU (Central Processing Unit). In Controller 5, the processor executes a program or instruction stored in the memory to realize a predetermined function. The function of Controller 5 may be realized by hardware alone, or by a combination of hardware and software.

[0022] The controller 5 controls the current supplied to the multiple coil units 4. The controller 5 controls the current, for example, by controlling an inverter. In this way, the controller 5 adjusts the heating power by adjusting the power supplied to the multiple coil units 4.

[0023] The operating device 6 is a device for operating the induction cooker 1. For example, the operating device 6 has the function of an input device for receiving information from the user and an output device for outputting information to the user. The operating device 6 may include an operation panel for the user to operate the induction cooker 1, buttons for the user to change the heat level, and a display and speaker for informing the user of the status of the induction cooker 1. For example, the user can adjust the heat level of multiple coil units 4 by operating the operating device 6.

[0024] Figure 2 is a schematic plan view showing the schematic configuration of the coil unit 4 of the induction heating cooker 1 according to Embodiment 1 of the present disclosure.

[0025] As shown in Figure 2, the coil unit 4 comprises a plurality of coils 10, 20. The plurality of coils 10, 20 include a first coil 10 and a second coil 20.

[0026] The first coil 10 comprises a plurality of coil pieces 11 to 14. The second coil 20 comprises a plurality of coil pieces 21 and 22. In this embodiment, the first coil 10 comprises four coil pieces 11 to 14, and the second coil 20 comprises two coil pieces 21 and 22. The first coil 10 is positioned in front of the induction cooker 1 than the second coil 20.

[0027] In the coil unit 4, the area occupied by the first coil 10 is greater than or equal to the area occupied by the second coil 20. In other words, the area occupied by the first coil 10 is equal to or greater than the area occupied by the second coil 20. In this embodiment, the area occupied by the first coil 10 is greater than the area occupied by the second coil 20. Specifically, in a plan view, the area where the first coil 10 is located is larger than the area where the second coil 20 is located relative to the entire area of ​​the coil unit 4. For example, the area occupied by the first coil is between 1.0 and 6 times the area occupied by the second coil.

[0028] Multiple coils 10 and 20 are arranged in a heating region S1 that heats an object to be heated in a plan view.

[0029] In this specification, "heating region S1" refers to the region in a plan view where the coil unit 4 is positioned and which is inductively heated by the coil unit 4. For example, heating region S1 is the region surrounding the outer periphery of the coil unit 4 in a plan view.

[0030] Within the heating region S1, the first coil 10 and the second coil 20 are adjacent to each other. The heating region S1 has a circular shape in plan view.

[0031] The heating region S1 has multiple coil arrangement regions S11 to S16. In a plan view, the multiple coil arrangement regions S11 to S16 are arranged radially and adjacent to each other with respect to the center C1 of the heating region S1. Specifically, the multiple coil arrangement regions S11 to S16 are defined in a plan view by multiple boundary lines L11 to L16 that extend radially from the center C1 of the heating region S1 toward the outer periphery, and by an outer periphery line L10 that defines the outer periphery of the heating region S1. In a plan view, the multiple coil arrangement regions S11 to S16 are formed in a fan shape. Note that the multiple boundary lines L11 to L16 and the outer periphery line L10 are virtual lines.

[0032] In this specification, a "sector shape" is defined in a plan view by two straight lines (radii) extending from the center of a circle toward its outer circumference, and by an arc connecting the two straight lines.

[0033] The multiple boundary lines L11 to L16 are arranged radially at equal intervals from the center C1 of the heating region S1 in a plan view. The multiple boundary lines L11 to L16 are straight lines extending from the center C1 of the heating region S1 toward the outer circumference in a plan view. The angles between two adjacent boundary lines L11 to L16 are approximately the same. As a result, in a plan view, the multiple coil arrangement regions S11 to S16 have approximately the same shape and approximately the same size. In this specification, "approximately" means an error of 10% or less, preferably an error of 5% or less.

[0034] The multiple coil pieces 11-14, 21, and 22 of the first coil 10 and the second coil 20 are each arranged within multiple coil arrangement regions S11-S16 in a plan view. Specifically, in the heating region S1, one coil piece is arranged within one coil arrangement region. As a result, the multiple coil pieces 11-14, 21, and 22 are arranged radially and adjacently within the heating region S1 in a plan view. In this embodiment, the number of coil pieces constituting the first coil 10 is greater than the number of coil pieces constituting the second coil 20. Specifically, the four coil pieces 11-14 of the first coil 10 are arranged in four coil arrangement regions S11-S14 and are adjacent to each other. The two coil pieces 21 and 22 of the second coil 20 are arranged in coil arrangement regions S15 and S16 and are adjacent to each other.

[0035] Multiple coil pieces 11-14, 21, 22 have coil wires that are wound and arranged in multiple coil arrangement regions S11-S16. In a plan view, the coil wires are arranged along two adjacent boundary lines among the multiple boundary lines L11-L16. Specifically, in a plan view, within one coil arrangement region, the coil wires are arranged along two adjacent boundary lines and an outer circumference line L10 connecting the two adjacent boundary lines, and are wound inward. In this embodiment, the multiple coil pieces 11-14, 21, 22 of the first coil 10 and the second coil 20 have substantially the same size and substantially the same shape.

[0036] In this specification, "arranged along two adjacent boundary lines" means, unless otherwise specified, that there are no other components obstructing the space between the boundary lines and the coil wire, and that the coil wire extends in approximately the same direction as the boundary lines. The same applies to "arranged along the outer perimeter line L10."

[0037] The shape of the heating region S1 is not limited to the examples described above. For example, the heating region S1 may be rectangular, elliptical, or regular polygonal in plan view. If the heating region S1 is rectangular in plan view, its center is the intersection of its diagonals. If the heating region S1 is elliptical in plan view, its center is the intersection of its major and minor axes. If the heating region S1 is a regular polygon in plan view, its center is the center of the inscribed circle that is tangent to all the outer sides constituting the regular polygon.

[0038] Figure 3 is a schematic block diagram showing an example of the main configuration of the induction heating cooker 1 of Embodiment 1 according to this disclosure.

[0039] As shown in Figure 3, the induction cooker 1 includes a relay 7 that switches the connection between the controller 5 and the first coil 10 ON / OFF.

[0040] In this specification, "continuity" means a state in which there is an electrical connection, and that current can be supplied from the controller 5, even if no current is actually flowing.

[0041] Relay 7 is positioned between the controller 5 and the first coil 10. Relay 7 is connected to multiple coil pieces 11-14 of the first coil 10. Relay 7 switches the conductivity between the controller 5 and the multiple coil pieces 11-14 of the first coil 10 ON / OFF. Relay 7 is controlled by the controller 5.

[0042] When relay 7 is turned ON, current can be supplied from controller 5 to the multiple coil pieces 11-14 of the first coil 10. When relay 7 is turned OFF, current cannot be supplied from controller 5 to the multiple coil pieces 11-14 of the first coil 10.

[0043] The second coil 20 is electrically connected to the controller 5. Multiple coil pieces 21 and 22 of the second coil 20 are electrically connected to the controller 5. Specifically, the multiple coil pieces 21 and 22 of the second coil 20 are directly connected to the controller 5 by wiring without the use of relays. Thus, the induction cooker 1 does not have a mechanism to switch the connection between the controller 5 and the second coil 20 ON / OFF, and the connection between the controller 5 and the second coil 20 is always maintained. For this reason, the second coil 20 is in a state where it can receive current from the controller 5.

[0044] [Operation] An example of the operation of the induction cooker 1 of Embodiment 1 will be explained using Figure 4.

[0045] Figure 4 is a flowchart illustrating an example of the operation of an induction heating cooker according to Embodiment 1 of the present disclosure. Figure 4 shows an example of the operation for detecting the object to be heated C placed on the top plate 2. For example, the detection operation is performed before the heating operation.

[0046] As shown in Figure 4, the induction cooker 1 detects the position of the object to be heated C by performing steps ST11 to ST15.

[0047] In step ST11, the controller 5 supplies a detection current to the second coil 20. In step ST11, the controller 5 does not supply a detection current to the first coil 10. Specifically, the controller 5 supplies a detection current to the second coil 20 while the relay 7 is turning off the conduction between the controller 5 and the first coil 10. The "detection current" is the current used to detect the object to be heated C.

[0048] In step ST12, the controller 5 detects whether or not the object to be heated C is placed in the heating region S1. The controller 5 detects whether or not the object to be heated C is placed in the heating region S1 including the second coil 20 based on the detection current flowing through the second coil 20. In step ST12, the controller 5 only needs to detect whether or not the object to be heated C is in the heating region S1, and does not need to detect the exact position of the object to be heated C. That is, the controller 5 either detects that the object to be heated C is placed somewhere in the heating region S1, or detects that the object to be heated C is not placed in the heating region S1.

[0049] For example, the controller 5 includes a circuit that detects changes in the detection current before and after it flows through multiple coils 10 and 20. Based on the change in the detection current flowing through the second coil 20, the controller 5 detects whether or not the object to be heated C is placed in the heating region S1.

[0050] If the controller 5 detects that the object to be heated C is not placed in the heating area S1, the flow proceeds to step ST13. If the controller 5 detects that the object to be heated C is placed in the heating area S1, the flow proceeds to step ST14.

[0051] In step ST13, the controller 5 determines whether a predetermined time has elapsed. For example, the controller 5 determines whether a predetermined time has elapsed since receiving the heating start signal. The predetermined time is, for example, 1 minute.

[0052] If the predetermined time has not elapsed, the flow returns to step ST12. If the predetermined time has elapsed, the controller 5 stops supplying the detection current, and the flow ends.

[0053] In step ST14, the controller 5 connects the controller 5 to the first coil 10. The controller 5 uses the relay 7 to turn on the connection between the controller 5 and the first coil 10. As a result, the first coil 10 and the second coil 20 are connected to the controller 5, and the controller 5 is able to supply detection current to the first coil 10 and the second coil 20.

[0054] In step ST15, the controller 5 supplies detection current to the first coil 10 and the second coil 20 to detect the position of the object to be heated C. Based on the detection current flowing through the first coil 10, the controller 5 detects the position of the object to be heated C in the heating region S1. For example, the controller 5 detects the position of the object to be heated C within the heating region S1. For example, the controller 5 detects the displacement of the object to be heated C relative to the heating region S1.

[0055] In this way, the induction cooker 1 roughly detects whether or not the object to be heated C is placed in the heating area S1 by supplying a detection current to the second coil 20. If the object to be heated C is not placed in the heating area S1, the controller 5 terminates the detection operation. In this case, the detection operation can be terminated without switching the relay 7, so no switching sound of the relay 7 is generated. Also, since no detection current is supplied to the first coil 20, the detection time can be shortened.

[0056] On the other hand, when the object to be heated C is placed in the heating region S1, the controller 5 uses the relay 7 to turn on the conduction between the controller 5 and the first coil 10 and supplies a detection current to the first coil 10. This allows the position of the object to be heated C to be detected, and thus any displacement of the object to be heated C can be detected.

[0057] [effect] The induction heating cooker 1 according to Embodiment 1 provides the following effects.

[0058] The induction cooker 1 of this disclosure comprises a top plate 2 on which an object to be heated C is placed, a coil unit 4 including a first coil 10 and a second coil 20 located below the top plate 2, a controller 5 for controlling the coil unit 4, and a relay 7 for switching the connection between the controller 5 and the first coil 10 ON / OFF. The second coil 20 is electrically connected to the controller 5. The controller 5 supplies a detection current to the second coil 20 for detecting the object to be heated C while the connection between the controller 5 and the first coil 10 is turned OFF by the relay 7. Based on the detection current flowing through the second coil 20, the controller 5 detects whether or not an object to be heated C is placed in the heating region S1 including the second coil 20.

[0059] This configuration reduces the number of times relay 7 needs to be switched. Specifically, since the second coil 20 and controller 5 remain in a conductive state, relay switching can be eliminated when supplying detection current to the second coil 20.

[0060] Furthermore, the controller 5 roughly detects whether or not the object to be heated C is placed in the heating area S1 by supplying a detection current to the second coil 20. As a result, if it detects that the object to be heated C is not placed in the heating area S1, the detection operation can be terminated without supplying a detection current to the first coil 10, thus shortening the detection time.

[0061] Furthermore, the controller 5 can quickly detect contact abnormalities in the relay 7 based on the detection current flowing through the second coil 20. For example, the controller 5 stores a threshold value for the detection current to detect contact abnormalities in the relay 7. The controller 5 detects a contact abnormality in the relay 7 when the detection current flowing through the second coil 20 is greater than the threshold value.

[0062] When the controller 5 detects that an object to be heated C is placed in the heating area S1, the relay 7 turns on the connection between the controller 5 and the first coil 10, supplying detection current to the first coil 10 and the second coil 20, thereby detecting the position of the object to be heated placed in the heating area S1.

[0063] With this configuration, it is possible to detect the position of the object to be heated C after detecting that the object to be heated C is placed in the heating region S1. For example, it is possible to detect any misalignment of the object to be heated C relative to the heating region S1.

[0064] In the coil unit 4, the area occupied by the first coil 10 is greater than or equal to the area occupied by the second coil 20.

[0065] This configuration allows for efficient detection of the object to be heated C. Because the amount of current supplied to the second coil 20 when detecting whether or not the object to be heated C is placed in the heating region S1 can be reduced, power consumption can be lowered compared to a configuration where detection current is supplied to all coils. Furthermore, if the area occupied by the second coil is smaller than the area occupied by the first coil, it becomes easier to pinpoint the location of the object to be heated C when detecting its position within the heating region S1.

[0066] Each of the first coil 10 and the second coil 20 includes a plurality of coil pieces 11-14, 21, and 22.

[0067] This configuration allows each coil to detect the object to be heated C, and the way the detection current flows can be varied for each coil. This enables accurate detection of the position or size of the object to be heated C.

[0068] Multiple coil pieces 11-14, 21, and 22 in the first coil 10 and the second coil 20 have substantially the same shape and substantially the same size.

[0069] This configuration makes it easier to compare which coil the object to be heated C is closest to, allowing for more accurate detection of the position or size of the object to be heated C. Furthermore, it reduces the manufacturing cost of the induction cooker 1.

[0070] In a plan view, the heating region S1 has multiple coil placement regions S11 to S16 defined by an outer peripheral line L10 that defines the outer periphery of the heating region S1, and multiple boundary lines L11 to L16 that extend radially from the center C1 of the heating region S1 toward the outer periphery. Multiple coil pieces 11 to 14, 21, and 22 in the first coil 10 and the second coil 20 are arranged within the multiple coil placement regions S11 to S16 in a plan view.

[0071] This configuration allows the outer circumference line L10 to closely resemble the shape of the bottom of the object C being heated, thereby enabling more accurate detection of the position or size of the object C.

[0072] When the controller 5 detects that no object to be heated C is placed in the heating region S1, it stops supplying the detection current.

[0073] With this configuration, if it is detected that the object to be heated C is not placed in the heating area S1, the supply of detection current is stopped and the detection operation is terminated, thereby shortening the detection time.

[0074] In this embodiment, an example of a built-in induction cooker 1 has been described, but it is not limited to this. For example, the induction cooker 1 may be a tabletop type cooker.

[0075] In this embodiment, an example in which the induction cooker 1 is equipped with an operating device 6 has been described, but it is not limited to this. The operating device 6 is not an essential component of the induction cooker 1. For example, the induction cooker 1 may be operated by an external device. The external device may be, for example, an information processing terminal such as a smartphone or tablet PC. The operating device 6 may be provided on the top plate 2, or it may be provided at any location on the induction cooker 1.

[0076] In this embodiment, an example has been described in which the coil unit 4 includes a first coil 10 and a second coil 20, but it is not limited to this. The coil unit 4 may include multiple coils. Furthermore, the arrangement of the multiple coils may be designed arbitrarily. For example, the multiple coils may be arranged in a grid or in a line.

[0077] In this embodiment, an example has been described in which the first coil 10 and the second coil 20 each comprise a plurality of coil pieces 11 to 14, 21, and 22, but the embodiment is not limited to this. For example, the first coil 10 and the second coil 20 may each comprise one or more coil pieces.

[0078] In this embodiment, an example has been described in which the first coil 10 is positioned in front of the induction cooker 1 than the second coil 20, but the embodiment is not limited to this. For example, the first coil 10 may be positioned behind the induction cooker 1 than the second coil 20.

[0079] In this embodiment, an example has been described in which the multiple coil pieces 11-14, 21, 22 constituting the first coil 10 and the second coil 20 have substantially the same shape and substantially the same size, but the embodiment is not limited to this. For example, the multiple coil pieces 11-14, 21, 22 may have different shapes and / or different sizes.

[0080] In this embodiment, an example has been described in which the multiple coil pieces 11 to 14 constituting the first coil 10 are adjacent to each other, and the multiple coil pieces 21 and 22 constituting the second coil 20 are adjacent to each other, but the embodiment is not limited to this. For example, the multiple coil pieces 11 to 14 of the first coil 10 do not have to be adjacent to each other. The multiple coil pieces 21 and 22 of the second coil 20 do not have to be adjacent to each other. For example, the multiple coil pieces 21 and 22 of the second coil 20 may be arranged opposite each other with the center C1 of the heating region S1 in between.

[0081] In this embodiment, an example in which there are six coil placement areas S11 to S16 has been described, but the number is not limited to this. The number of coil placement areas S11 to S16 can be designed arbitrarily.

[0082] In this embodiment, an example has been described in which the multiple coil placement areas S11 to S16 are substantially the same shape and size, but the embodiment is not limited to this. For example, the multiple coil placement areas S11 to S16 may have different shapes and / or different sizes.

[0083] In this embodiment, an example has been described in which the second coil 20 and the controller 5 are directly connected by wiring without a relay, thereby ensuring conductivity, but the embodiment is not limited to this. It is sufficient that the second coil 20 and the controller 5 remain electrically connected. For example, a relay may be placed between the second coil 20 and the controller 5. In this case, the controller 5 may control the relay to maintain the conductivity between the second coil 20 and the controller 5 during the detection operation.

[0084] In this embodiment, an example has been described in which the area occupied by the first coil 10 is larger than the area occupied by the second coil 20, but the embodiment is not limited to this. For example, the area occupied by the first coil 10 may be less than or equal to the area occupied by the second coil 20.

[0085] (Embodiment 2) An induction heating cooker according to Embodiment 2 of the present invention will now be described.

[0086] Embodiment 2 will primarily describe the differences from Embodiment 1. In Embodiment 2, components identical or equivalent to those in Embodiment 1 will be denoted by the same reference numerals. Furthermore, in Embodiment 2, descriptions that overlap with those in Embodiment 1 will be omitted.

[0087] Figure 5 is a schematic plan view showing the schematic configuration of the induction cooker 1 according to Embodiment 2 of the present disclosure. Figure 6 is a schematic plan view showing the schematic configuration of the coil unit 4A of the induction cooker 1 according to Embodiment 2 of the present disclosure.

[0088] Embodiment 2 differs from Embodiment 1 in that the coil unit 4A includes a third coil 30.

[0089] As shown in Figures 5 and 6, the coil unit 4A includes a third coil 30 in addition to the first coil 10 and the second coil 20.

[0090] The third coil 30 is located below the top plate 2 and is positioned further back than the second coil 20 in the induction cooker 1. In a plan view, the second coil 20 is located between the first coil 10 and the third coil 30. In a plan view, the second coil 20 is located in the center of the coil unit 4A.

[0091] The second coil 20 is positioned in the center of the top plate 2 in the front-to-back direction in a plan view. As shown in Figure 5, a virtual center line CL1 is drawn in the front-to-back direction of the top plate 2 in a plan view. The virtual center line CL1 is a virtual line that is equidistant from the front and rear ends of the top plate 2. The second coil 20 is located on the virtual center line CL1.

[0092] In this embodiment, the induction cooker 1 comprises two coil units 4A arranged at a distance from each other in the left-right direction of the top plate 2 in a plan view. As shown in Figure 5, a virtual center line CL2 is drawn in the left-right direction of the top plate 2 in a plan view. The virtual center line CL2 is a virtual line that is equidistant from the left and right ends of the top plate 2. The two coil units 4A are arranged on the left and right sides with the virtual center line CL2 in between.

[0093] The third coil 30 comprises a plurality of coil pieces 31 to 34. In this embodiment, the third coil 30 has substantially the same configuration as the first coil 10. That is, the third coil 30 comprises four coil pieces 31 to 34. The four coil pieces 31 to 34 of the third coil 30 have substantially the same shape and size as the four coil pieces 11 to 14 of the first coil 10. Furthermore, the four coil pieces 31 to 34 of the third coil 30 are arranged adjacent to each other, similar to the first coil 10.

[0094] In the coil unit 4, the area occupied by the third coil 30 is larger than the area occupied by the second coil 20. Specifically, in a plan view, the area where the third coil 30 is located is larger than the area where the second coil 20 is located relative to the entire area of ​​the coil unit 4.

[0095] The heating region includes, in a plan view, a first heating region S1 defined by the first coil 10 and the second coil 20, and a second heating region S2 defined by the second coil 20 and the third coil 30. In a plan view, the heating region has an overlapping region DS1 in which the first heating region S1 and the second heating region S2 partially overlap. The second coil 20 is positioned in the overlapping region DS1 that overlaps the first heating region S1 and the second heating region S2.

[0096] The first heating region S1 is the same as the heating region S1 in Embodiment 1, so its description will be omitted. In this embodiment, the coil arrangement region in the first heating region S1 is referred to as the first coil arrangement region, and the coil arrangement region in the second heating region S2 is referred to as the second coil arrangement region. Furthermore, the outer perimeter line and multiple boundary lines defining the first coil arrangement region are referred to as the first outer perimeter line and multiple first boundary lines, and the outer perimeter line and multiple boundary lines defining the second coil arrangement region are referred to as the second outer perimeter line and multiple second boundary lines.

[0097] The second heating region S2 is a region having a center C2 in a plan view, and is the region in which the second coil 20 and the third coil 30 are arranged. Within the second heating region S2, the second coil 20 and the third coil 30 are adjacent to each other. Specifically, in a plan view, the multiple coil pieces 21, 22, 31-34 constituting the second coil 20 and the third coil 30 are arranged radially within the second heating region S2. In this embodiment, the second heating region S2 has a circular shape in a plan view. However, the second heating region S2 is not limited to having a circular shape in a plan view.

[0098] The second heating region S2 has a plurality of second coil arrangement regions S21 to S26. In a plan view, the plurality of second coil arrangement regions S21 to S26 are arranged radially and adjacent to each other with respect to the center C2 of the second heating region S2. Specifically, the plurality of second coil arrangement regions S21 to S26 are defined by a plurality of second boundary lines L21 to L26 that extend radially from the center C2 of the second heating region S2 toward the outer periphery in a plan view, and an outer second periphery line L20 that defines the outer periphery of the second heating region S2. Note that the plurality of second boundary lines L21 to L26 and the second periphery line L20 are virtual lines.

[0099] The multiple second boundary lines L21 to L26 are arranged radially at equal intervals from the center C2 of the second heating region S2 in a plan view. The multiple second boundary lines L21 to L26 are straight lines extending from the center C2 of the second heating region S2 toward the outer circumference in a plan view. The angles between two adjacent boundary lines L21 to L26 are approximately the same. As a result, in a plan view, the multiple second coil arrangement regions S21 to S26 have approximately the same shape and dimensions.

[0100] Each of the multiple second coil placement regions S21 to S26 has a fan shape in plan view.

[0101] Furthermore, in this embodiment, the two second coil arrangement regions S25 and S26 in the second heating region S2 overlap with the two first coil arrangement regions S15 and S16 in the first heating region S1. That is, the two second coil arrangement regions S25 and S26 in the second heating region S2 and the two first coil arrangement regions S11 and S12 in the first heating region S1 form an overlapping region DS1. Also, the second boundary line L26 in the second heating region S2 overlaps with the boundary line L16 in the first heating region S1.

[0102] In the second heating region S2, the multiple coil pieces 21, 22, 31-34 constituting the second coil 20 and the third coil 30 are each arranged within multiple second coil arrangement regions S21-S26 in a plan view. As a result, the multiple coil pieces 21, 22, 31-34 are arranged radially and adjacent to each other within the second heating region S2 in a plan view.

[0103] In this embodiment, the two coil pieces 21 and 22 of the second coil 20 are shared between the first heating region S1 and the second heating region S2. The two coil pieces 21 and 22 of the second coil 20 are arranged in two coil arrangement regions S25 and S26 within the second heating region S2 and in two coil arrangement regions S15 and S16 within the first heating region S1.

[0104] For example, the controller 5 can perform first to third heating states by controlling the high-frequency current supplied to the multiple coils 10, 20, and 30 of the coil unit 4A. For example, the first heating state is a state in which heating is performed by the first coil 10 and the second coil 20 located in the first heating region S1. The second heating state is a state in which heating is performed by the second coil 20 and the third coil 30 located in the second heating region S2. The third heating state is a state in which heating is performed by the first to third coils 10, 20, and 30 located in the first heating region S1 and the second heating region S2.

[0105] Figure 7 is a schematic block diagram showing an example of the main configuration of the induction heating cooker 1 of Embodiment 2 according to this disclosure.

[0106] As shown in Figure 7, the induction cooker 1 is equipped with a relay 8 that switches the connection between the controller 5 and the third coil 30 ON / OFF. In this embodiment, the relay 7 that switches the connection between the controller 5 and the first coil 10 ON / OFF is referred to as the first relay 7, and the relay 8 that switches the connection between the controller 5 and the third coil 30 ON / OFF is referred to as the second relay 8.

[0107] The first relay 7 is the same as the relay 7 in Embodiment 1, so its description is omitted.

[0108] The second relay 8 is positioned between the controller 5 and the third coil 30. The second relay 8 is connected to multiple coil pieces 31-34 of the third coil 30. The second relay 8 switches the conductivity between the controller 5 and the multiple coil pieces 31-34 of the third coil 30 ON / OFF. The second relay 8 is controlled by the controller 5.

[0109] When the second relay 8 is turned ON, the controller 5 can supply current to the multiple coil pieces 31-34 of the third coil 30. When the second relay 8 is turned OFF, the controller 5 does not supply current to the multiple coil pieces 31-34 of the third coil 30.

[0110] [Operation] An example of the operation of the induction cooker 1 of Embodiment 2 will be explained using Figure 8.

[0111] Figure 8 is a flowchart illustrating an example of the operation of the induction heating cooker 1 according to Embodiment 2 of this disclosure. Figure 8 shows an example of the operation for detecting the position of the object to be heated C placed on the top plate 2. For example, the detection operation is performed before the heating operation.

[0112] As shown in Figure 8, the induction cooker 1 detects the position of the object to be heated C by performing steps ST21 to ST27.

[0113] In step ST21, the controller 5 supplies a detection current to the second coil 20. In step ST11, the controller 5 does not supply a detection current to the first coil 10 and the third coil 30. Specifically, the controller 5 turns off the continuity between the controller 5 and the first coil 10 using the first relay 7, and turns off the continuity between the controller 5 and the third coil 30 using the second relay 8. In this state, the controller 5 supplies a detection current to the second coil 20.

[0114] In step ST22, the controller 5 detects whether or not the object to be heated C is placed in the heating regions S1 and S2. Based on the detection current flowing through the second coil 20, the controller 5 detects whether or not the object to be heated C is placed in the heating regions S1 and S2, which include the second coil 20. In step ST22, the controller 5 detects that the object to be heated C is placed in at least one of the first heating region S1 and the second heating region S2, but does not need to detect the specific location of the object to be heated C. That is, the controller 5 detects that the object to be heated C is not placed in both the first heating region S1 and the second heating region S2, or detects that the object to be heated C is placed somewhere in the first heating region S1 and the second heating region S2.

[0115] If controller 5 detects that the object to be heated C is not placed in heating regions S1 and S2, the flow proceeds to step ST23. If controller 5 detects that the object to be heated C is placed in heating regions S1 and S2, the flow proceeds to step ST24.

[0116] Step ST23 is the same as step ST13 in Embodiment 1, so its description is omitted.

[0117] In step ST24, when the controller 5 detects that the object to be heated C is placed in the heating area, it connects the controller 5 to the first coil 10. The controller 5 turns on the connection between the controller 5 and the first coil 10 using the first relay 7. The controller 5 maintains the connection between the controller 5 and the third coil 30 in the OFF position using the second relay 8. As a result, the first coil 10 and the second coil 20 are connected to the controller 5, and the controller 5 is able to supply detection current to the first coil 10 and the second coil 20.

[0118] In step ST25, the controller 5 supplies detection current to the first coil 10 and the second coil 20 to detect whether or not the object to be heated C is placed within the first heating region S1. Based on the detection current flowing through the first coil 10, the controller 5 detects whether or not the object to be heated C is placed within the first heating region S1.

[0119] In step ST26, the controller 5 connects the controller 5 to the third coil 30. The controller 5 turns on the connection between the controller 5 and the third coil 30 using the second relay 8. The controller 5 turns off the connection between the controller 5 and the first coil 10 using the first relay 7. As a result, the second coil 20 and the third coil 30 are connected to the controller 5, and the controller 5 is able to supply detection current to the second coil 20 and the third coil 30.

[0120] In step ST27, the controller 5 supplies detection current to the second coil 20 and the third coil 30 to detect whether or not the object to be heated C is placed within the second heating region S2. Based on the detection current flowing through the third coil 30, the controller 5 detects whether or not the object to be heated C is placed within the second heating region S2.

[0121] Thus, the induction cooker 1 detects that the object to be heated C is placed in heating regions S1 and S2, and then detects that the object to be heated C is placed in the first heating region S1 and / or the second heating region S2.

[0122] For example, if the controller 5 detects that the object to be heated C is placed in the first heating area S1 and not in the second heating area S2, the controller 5 supplies high-frequency current to the first coil 10 and the second coil 20 to heat the object to be heated C. If the controller 5 detects that the object to be heated C is not placed in the first heating area S1 but is placed in the second heating area S2, the controller 5 supplies high-frequency current to the second coil 20 and the third coil 30 to heat the object to be heated C. If the controller 5 detects that the object to be heated C is placed in both the first heating area S1 and the second heating area S2, the controller 5 supplies high-frequency current to the first to third coils 10 to 30 to heat the object to be heated C.

[0123] [effect] The induction heating cooker 1 according to Embodiment 2 provides the following effects.

[0124] In the induction cooker 1 of this disclosure, the coil unit 4A further comprises a third coil 30 located below the top plate 2, and the second coil 20 is located between the first coil 10 and the third coil 30.

[0125] Even with this configuration, the number of relay switching cycles can be reduced. Furthermore, the position of the object to be heated C can be detected quickly, shortening the detection time.

[0126] The heating region includes a first heating region S1 defined by the first coil 10 and the second coil 20, and a second heating region S2 defined by the second coil 20 and the third coil 30. The second coil 20 is positioned in the overlapping region DS1 where the first heating region S1 and the second heating region S2 overlap.

[0127] This configuration makes it easier to detect the position of the object to be heated C. The second coil 20 is used regardless of whether heating is performed in the first heating region S1 or the second heating region S2. Therefore, by supplying a detection current to the second coil 20, it is possible to quickly detect that the object to be heated C is not placed in either the first heating region S1 or the second heating region S2. This reduces the detection time.

[0128] The second coil 20 is positioned in the center of the top plate 2 in the front-to-back direction when viewed from above.

[0129] This configuration allows for more accurate detection of the position or size of the object C being heated.

[0130] The first coil 10 and the third coil 30 have substantially the same configuration.

[0131] This configuration makes it easier to compare which coil the object to be heated C is closest to, allowing for more accurate detection of the position or size of the object to be heated C. Furthermore, it reduces the manufacturing cost of the induction cooker 1.

[0132] Each of the first coil 10, the second coil 20, and the third coil 30 includes a plurality of coil pieces 11-14, 21, 22, 31-34.

[0133] This configuration allows each coil to detect the object to be heated C, and the way the detection current flows can be varied for each coil. This enables more accurate detection of the position or size of the object to be heated C.

[0134] The induction cooker 1 includes a second relay 8 that switches the connection between the controller 5 and the third coil 30 ON / OFF. The controller 5 supplies a detection current to the second coil 20 while the connection between the controller 5 and the third coil 30 is OFF by the second relay 8.

[0135] This configuration reduces the number of times relays 7 and 8 are switched. Furthermore, if the controller detects that the object to be heated C is not placed in the heating area, the detection operation can be terminated without supplying detection current to the third coil 30, thus shortening the detection time. The controller 5 can also quickly detect contact abnormalities in relays 7 and 8 based on the detection current flowing through the second coil 20.

[0136] When the controller 5 detects that an object to be heated C is placed in the heating area, the second relay 8 turns on the conductivity between the controller 5 and the third coil 30, supplying detection current to the second coil 20 and the third coil 30, and detects the position of the object to be heated C placed in the heating area.

[0137] With this configuration, it is possible to detect the position of the object to be heated C after detecting that it is placed in the heating region. For example, it is possible to detect that the object to be heated C is placed within the second heating region S2 based on the detection current flowing through the third coil. It is also possible to detect any positional displacement of the object to be heated C relative to the second heating region S2.

[0138] When the controller 5 detects that the object to be heated C is placed in the heating area, the first relay 7 turns on the continuity between the controller 5 and the first coil 10, supplying detection current to the first coil 10 and the second coil 20, thereby detecting whether or not the object to be heated C is placed in the first heating area S1. The controller 5 also turns on the continuity between the controller 5 and the third coil 30, supplying detection current to the second coil 20 and the third coil 30, thereby detecting whether or not the object to be heated C is placed in the second heating area S2.

[0139] This configuration allows for quick and accurate detection of the position of the object C to be heated.

[0140] The first heating region S1 has a plurality of first coil placement regions S11 to S16 defined by a first outer peripheral line L10 that defines the outer periphery of the first heating region S1, and a plurality of first boundary lines L11 to L16 that extend radially from the center C1 of the first heating region S1 toward the outer periphery. The second heating region S2 has a plurality of second coil placement regions S21 to S26 defined by a second outer peripheral line L20 that defines the outer periphery of the second heating region S2, and a plurality of second boundary lines L21 to L26 that extend radially from the center C2 of the second heating region S2 toward the outer periphery. The plurality of coil pieces 11 to 14 in the first coil 10 are arranged in the plurality of first coil placement regions S11 to S14. The plurality of coil pieces 21 and 22 in the second coil 20 are arranged in the plurality of first coil placement regions S15 and S16 and the plurality of second coil placement regions S25 and S26 located in the overlapping region DS1. Multiple coil pieces 31 to 34 in the third coil 30 are arranged in multiple second coil arrangement regions S21 to S24.

[0141] With this configuration, the first outer circumference line L10 and the second outer circumference line L20 can be made to closely match the shape of the bottom of the object to be heated C, thereby enabling more accurate detection of the position or size of the object to be heated C.

[0142] In this embodiment, an example was described in which the first heating region S1 and the second heating region S2 partially overlap in a plan view, but the embodiment is not limited to this. For example, the first heating region S1 and the second heating region S2 do not have to partially overlap. That is, the second coil 20 does not have to be shared between the first heating region S1 and the second heating region S2.

[0143] In this embodiment, an example in which two heating regions S1 and S2 are provided has been described, but the invention is not limited to this. For example, two or more heating regions may be provided.

[0144] In this embodiment, an example has been described in which the first coil 10 and the third coil 30 have substantially the same configuration, but the embodiment is not limited to this. For example, the first coil 10 and the third coil 30 may have different configurations.

[0145] In this embodiment, examples have been described in which the second coil 20 is positioned in the center of the top plate 2 in the front-to-back direction in a plan view, and in which the two coil units 4A are positioned spaced apart in the left-to-right direction of the top plate 2 in a plan view, but the embodiment is not limited to these examples.

[0146] Figures 9-11 are schematic plan views showing another example of the position of the second coil 20 relative to the top plate 2.

[0147] As shown in Figure 9, in a plan view, one coil unit 4A may be positioned in the center of the top plate 2. In this case, the second coil 20 may also be positioned in the center of the top plate 2 in a plan view. In a plan view, the second coil 20 may be located on two virtual centerlines CL1 and CL2.

[0148] As shown in Figure 10, in a plan view, the two coil units 4A may be arranged side by side in the front-to-back direction of the top plate 2, and the first coil 10 and the third coil 30 may be arranged in the left-to-right direction of the second coil 20. In this case, the second coil 20 may be positioned in the center in the left-to-right direction of the top plate 2 in a plan view. In a plan view, the second coil 20 may be located on the virtual center line CL2.

[0149] As shown in Figure 11, in a plan view, one coil unit 4A may be positioned in the center of the top plate 2, and the first coil 10 and the third coil 30 may be positioned to the left and right of the second coil 20. In this case, the second coil 20 may be positioned in the center of the top plate 2 in a plan view. In a plan view, the second coil 20 may be located on two virtual centerlines CL1 and CL2.

[0150] The following describes some variations.

[0151] (Variation 1) An induction heating cooker 1 of Modification 1 of this disclosure will be explained with reference to Figure 12.

[0152] Figure 12 is a schematic diagram of the induction heating cooker 1 according to the first modified example.

[0153] As shown in Figure 12, the induction cooker 1 of Modified Example 1 is equipped with first to fourth relays 7A, 7B, 8A, and 8B. The other configurations of the induction cooker 1 of Modified Example 1 are the same as those of the induction cooker 1 of Embodiment 2.

[0154] The first relay 7A and the second relay 7B are positioned between the controller 5 and the first coil 10. The first relay 7A is connected to two coil pieces 11 and 13 of the first coil 10. The first relay 7A switches the continuity between the controller 5 and the two coil pieces 11 and 13 ON / OFF. The second relay 7B is connected to two coil pieces 12 and 14 of the first coil 10. The second relay 7B switches the continuity between the controller 5 and the two coil pieces 12 and 14 ON / OFF.

[0155] The third relay 8A and the fourth relay 8B are located between the controller 5 and the third coil 30. The third relay 8A is connected to two coil pieces 31 and 33 of the third coil 30. The third relay 8A switches the continuity between the controller 5 and the two coil pieces 31 and 33 ON / OFF. The fourth relay 8B is connected to two coil pieces 32 and 34 of the third coil 30. The fourth relay 8B switches the continuity between the controller 5 and the two coil pieces 32 and 34 ON / OFF.

[0156] Even with this configuration, the number of relay switching cycles can be reduced.

[0157] (Modification 2) An induction heating cooker 1 of Modification 2 of this disclosure will be explained with reference to Figure 13.

[0158] Figure 13 is a schematic diagram of the induction heating cooker 1 according to modified example 2.

[0159] As shown in Figure 13, in the modified example 2 induction cooker 1, the first to third coils 10A to 30A of the coil unit 4B are each composed of a single coil piece. The other configurations of the modified example 2 induction cooker 1 are the same as those of the induction cooker 1 of embodiment 1.

[0160] Even with this configuration, the number of relay switching cycles can be reduced.

[0161] In Modification 2, an example was described in which the coil unit 4B has three coils 10A to 30A, but it is not limited to this. For example, the coil unit 4B may have three or more coils.

[0162] As described above, the above embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited thereto and can be applied to embodiments that are modified, replaced, added, or omitted as appropriate.

[0163] While this disclosure is adequately described in relation to preferred embodiments with reference to the accompanying drawings, various modifications and alterations will be obvious to those skilled in the art. Such modifications and alterations should be understood to be included within the scope of the invention as defined by the appended claims.

[0164] (Summary of the embodiment) (1) The induction heating cooker of the present disclosure comprises a top plate on which an object to be heated is placed, a coil unit including a first coil and a second coil disposed below the top plate, a controller for controlling the coil unit, and a first relay for switching the connection between the controller and the first coil ON / OFF, wherein the second coil is electrically connected to the controller, and the controller supplies a detection current to the second coil for detecting the object to be heated while the connection between the controller and the first coil is turned OFF by the first relay, and detects whether or not the object to be heated is placed in the heating region including the second coil based on the detection current flowing through the second coil.

[0165] (2) In the induction heating cooker of (1), when the controller detects that the object to be heated is placed in the heating area, it may use the first relay to turn on the conduction between the controller and the first coil, supplying the detection current to the first coil and the second coil, and detect the position of the object to be heated placed in the heating area.

[0166] (3) In the induction heating cooker of (1) or (2), the area occupied by the first coil in the coil unit may be greater than or equal to the area occupied by the second coil.

[0167] (4) In any one of the induction cookers described in (1) to (3), each of the first coil and the second coil may include a plurality of coil pieces.

[0168] (5) In the induction heating cooker of (4), the plurality of coil pieces in the first coil and the second coil may have substantially the same shape and substantially the same size.

[0169] In the induction heating cooker of (6), (4), or (5), the heating region may have a plurality of coil arrangement regions defined in plan view by an outer peripheral line defining the outer periphery of the heating region and a plurality of boundary lines extending radially from the center of the heating region toward the outer periphery, and the plurality of coil pieces in the first coil and the second coil may be arranged within the plurality of coil arrangement regions in plan view.

[0170] (7) In any induction heating cooker according to (1) to (3), the coil unit may further include a third coil located below the top plate, and the second coil may be located between the first coil and the third coil.

[0171] (8)(7) In the induction heating cooker, the heating region may include a first heating region defined by the first coil and the second coil, and a second heating region defined by the second coil and the third coil, and the second coil may be located in an overlapping region where the first heating region and the second heating region overlap.

[0172] In the induction cooker of (9), (7), or (8), the second coil may be positioned in the center of the top plate in a plan view.

[0173] In the induction cooker of (10), (7), or (8), the second coil may be positioned in the center of the top plate in the front-to-back direction in a plan view.

[0174] In the induction cooker of (11), (7), or (8), the second coil may be positioned in the center of the top plate in the left-right direction in a plan view.

[0175] In any one of the induction cookers described in (12)(7) to (11), the first coil and the third coil may have substantially the same configuration.

[0176] In any one of the induction cookers described in (13)(7) to (12), each of the first coil, the second coil, and the third coil may include a plurality of coil pieces.

[0177] Any one of the induction cookers described in (14)(7) to (13) may further include a second relay for switching the conduction between the controller and the third coil ON / OFF, and the controller may supply the detection current to the second coil while the conduction between the controller and the third coil is turned OFF by the second relay.

[0178] In the induction heating cooker of (15)(14), when the controller detects that the object to be heated is placed in the heating area, it may use the second relay to turn on the conduction between the controller and the third coil, supplying the detection current to the second coil and the third coil, and detect the position of the object to be heated placed in the heating area.

[0179] In the induction heating cooker of (16)(8), a second relay may be further provided for switching the conduction between the controller and the third coil ON / OFF. The controller may supply a detection current to the second coil for detecting the object to be heated while the conduction between the controller and the third coil is OFF by the second relay. When it is detected that the object to be heated is placed in the heating area, the first relay may turn ON the conduction between the controller and the first coil and supply the detection current to the first coil and the second coil to detect whether or not the object to be heated is placed in the first heating area. Alternatively, the second relay may turn ON the conduction between the controller and the third coil and supply the detection current to the second coil and the third coil to detect whether or not the object to be heated is placed in the second heating area.

[0180] In the induction heating cooker of (17), (8), or (16), each of the first coil, the second coil, and the third coil may include a plurality of coil pieces, the first heating region may have a plurality of first coil arrangement regions defined by a first outer peripheral line defining the outer periphery of the first heating region and a plurality of first boundary lines extending radially from the center of the first heating region toward the outer periphery, the second heating region may have a plurality of second coil arrangement regions defined by a second outer peripheral line defining the outer periphery of the second heating region and a plurality of second boundary lines extending radially from the center of the second heating region toward the outer periphery, the plurality of coil pieces in the first coil may be arranged in the plurality of first coil arrangement regions and the plurality of second coil arrangement regions located in the overlapping region, and the plurality of coil pieces in the third coil may be arranged in the plurality of second coil arrangement regions.

[0181] (18) In any one of the induction heating cookers described in (1) to (17), the controller may stop supplying the detection current when it detects that the object to be heated is not placed in the heating area. [Industrial applicability]

[0182] This disclosure is applicable to induction cookers that use induction heating to heat objects such as pots and pans. [Explanation of Symbols]

[0183] 1,1A induction cooker 2 Top Plate 3 cabinets 4, 4A, 4B Coil Unit 5 Controllers 6 Operating device 7, 7A, 7B Relays 8,8A,8B relay 10,10A First coil 11, 12, 13, 14 Coil pieces 20,20A Second coil 21,22 Coil Pieces 30,30A Third coil 31, 32, 33, 34 Coil pieces C1,C2 center L11~L16 Boundary Line L21~L26 Boundary Line L10, L20 Outer perimeter lines S1 heating area (1st heating area) S2 heating area (second heating area) DS1 overlap area

Claims

1. A top plate on which the object to be heated is placed, A coil unit including a first coil and a second coil positioned below the top plate, A controller that controls the coil unit, A first relay that switches the conduction between the controller and the first coil ON / OFF, Equipped with, The second coil is electrically connected to the controller. The aforementioned controller, With the first relay turning off the conduction between the controller and the first coil, a detection current for detecting the object to be heated is supplied to the second coil. Based on the detection current flowing through the second coil, it is detected whether or not the object to be heated is placed in the heating region including the second coil. Induction heating cooker.

2. When the controller detects that the object to be heated is placed in the heating area, it turns on the conduction between the controller and the first coil using the first relay, supplies the detection current to the first coil and the second coil, and detects the position of the object to be heated placed in the heating area. The induction heating cooker according to claim 1.

3. In the coil unit, the area occupied by the first coil is greater than or equal to the area occupied by the second coil. The induction heating cooker according to claim 1.

4. Each of the first coil and the second coil includes a plurality of coil pieces. The induction heating cooker according to claim 1.

5. The plurality of coil pieces in the first coil and the second coil have substantially the same shape and substantially the same size. The induction heating cooker according to claim 4.

6. The heating region has, in a plan view, a plurality of coil arrangement regions defined by an outer peripheral line defining the outer periphery of the heating region and a plurality of boundary lines extending radially from the center of the heating region toward the outer periphery. The plurality of coil pieces in the first coil and the second coil are arranged within the plurality of coil arrangement regions in a plan view. The induction heating cooker according to claim 4.

7. The coil unit further comprises a third coil located below the top plate, The second coil is positioned between the first coil and the third coil. The induction heating cooker according to claim 1.

8. The heating region includes a first heating region defined by the first coil and the second coil, and a second heating region defined by the second coil and the third coil. The second coil is positioned in the overlapping region where the first heating region and the second heating region overlap. The induction heating cooker according to claim 7.

9. The second coil is positioned in the center of the top plate in a plan view. The induction heating cooker according to claim 7.

10. The second coil is positioned in the center of the top plate in the front-to-back direction in a plan view. The induction heating cooker according to claim 7.

11. The second coil is positioned in the center of the top plate in the left-right direction when viewed from above. The induction heating cooker according to claim 7.

12. The first coil and the third coil have substantially the same configuration. The induction heating cooker according to claim 7.

13. Each of the first coil, the second coil, and the third coil includes a plurality of coil pieces. The induction heating cooker according to claim 7.

14. The system further includes a second relay that switches the conduction between the controller and the third coil ON / OFF, The controller supplies the detection current to the second coil while the second relay is turning off the conduction between the controller and the third coil. The induction heating cooker according to claim 7.

15. When the controller detects that the object to be heated is placed in the heating area, it uses the second relay to turn on the conduction between the controller and the third coil, supplying the detection current to the second and third coils, and detects the position of the object to be heated placed in the heating area. The induction heating cooker according to claim 14.

16. The system further includes a second relay that switches the conduction between the controller and the third coil ON / OFF, The aforementioned controller, With the second relay turning off the conduction between the controller and the third coil, the detection current is supplied to the second coil. When it is detected that the object to be heated is placed in the heating region, The first relay turns on the conduction between the controller and the first coil, supplying the detection current to the first coil and the second coil, and detecting whether or not the object to be heated is placed in the first heating area. The second relay turns on the conduction between the controller and the third coil, supplying the detection current to the second coil and the third coil, and detecting whether or not the object to be heated is placed in the second heating region. The induction heating cooker according to claim 8.

17. Each of the first coil, the second coil, and the third coil includes a plurality of coil pieces. The first heating region has a plurality of first coil arrangement regions defined by a first outer peripheral line defining the outer periphery of the first heating region and a plurality of first boundary lines extending radially from the center of the first heating region toward the outer periphery. The second heating region has a plurality of second coil arrangement regions defined by a second outer peripheral line defining the outer periphery of the second heating region and a plurality of second boundary lines extending radially from the center of the second heating region toward the outer periphery. The plurality of coil pieces in the first coil are arranged in the plurality of first coil arrangement regions. The plurality of coil pieces in the second coil are arranged in the plurality of first coil arrangement regions and the plurality of second coil arrangement regions located in the overlapping region. The plurality of coil pieces in the third coil are arranged in the plurality of second coil arrangement regions. The induction heating cooker according to claim 8.

18. When the controller detects that the object to be heated is not placed in the heating area, it stops supplying the detection current. An induction heating cooker according to any one of claims 1 to 17.

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