EP3013121A1

EP3013121A1 - Induction heating cooker

Info

Publication number: EP3013121A1
Application number: EP14813316.8A
Authority: EP
Inventors: Teruo Hayashinaka; Hiroshi Tominaga
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2013-06-18
Filing date: 2014-05-30
Publication date: 2016-04-27
Anticipated expiration: 2034-05-30
Also published as: ES2654439T3; WO2014203468A1; JPWO2014203468A1; EP3013121A4; JP6303135B2; EP3013121B1

Abstract

An induction heating cooker of the present invention includes first and second induction heating units (61, 62), each of first and second induction heating units (61, 62) including: a plurality of induction heating coils (31, 32, 33, 34); a plurality of inverters (41, 42, 43, 44) that individually drive a plurality of induction heating coils (31 to 34); a temperature detector that detects a temperature of cooking container (11, 12); and power supply and controller (51, 52) that supplies power to inverters (41 to 44), and controls inverters (41 to 44) in accordance with an output of the temperature detector. In first induction heating unit (61), one infrared sensor (81) of the infrared sensors included in the temperature detector is provided in association with one of induction heating coils (31) provided at a foremost position. In second induction heating unit (62), one infrared sensor (82) of the infrared sensors included in the temperature detector is provided in association with one of induction heating coils (34) provided at a rearmost position. According to the present invention, it is possible to configure a lower cost induction heating cooker enabling high accurate heating control by temperature detection with good responsiveness.

Description

TECHNICAL FIELD

The present invention relates to an induction heating cooker.

BACKGROUND ART

Recently, in induction heating cookers, there is a machine type in which an infrared sensor installed below a top plate detects a temperature of a cooking container such as a pan placed on a top plate, and heating control is performed in accordance with detected temperature information (e.g., see PTL 1).
FIG. 4 is a schematic diagram illustrating an example of a conventional induction heating cooker. This conventional technology is described with reference to FIG. 4.
In FIG. 4, cooking container 10 for storing a cooking material is placed on top plate 20 configured by a non-magnetic body. Induction heating coil 30 generates an induction field for inductively heating cooking container 10.
Infrared sensor 80 includes a photodiode, receives an infrared ray emitted from cooking container 10 through top plate 20, and detects temperature information of cooking container 10. Power supply and controller 50 adjusts a drive signal output from inverter 40, in accordance with the temperature information detected by infrared sensor 80, and controls a high-frequency current generated by induction heating coil 30.
In the above configuration, a light receiving sensitivity wavelength region of infrared sensor 80 is designed so as to overlap with an infrared ray transmission wavelength region of top plate 20, and therefore infrared sensor 80 can detect the temperature of cooking container 10 with good response. Power supply and controller 50 suitably controls the temperature of cooking container 10 based on this detected result.

Citation List

Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2005-63881

SUMMARY OF THE INVENTION

However, the infrared sensor is generally more expensive than a temperature sensor having a simple configuration such as a thermistor, and therefore in an induction heating cooker having a plurality of induction heating coils, when an infrared sensor is provided in association with each of the induction heating coils, a total cost increases.
In a case where heating control is performed by use of the infrared sensor, a controller configured by a microcomputer needs to convert an output signal from the infrared sensor into temperature information which can be used in control of a heating output. Furthermore, the controller sometimes corrects the temperature information in accordance with the temperature information of the infrared sensor.
Therefore, in order to perform a complicated process of performing heating control by use of a current heating output and temperature information, the controller needs to previously store data necessary for the process.
As a result, in the induction heating cooker that controls each inverter in accordance with an output of each of the plurality of infrared sensors provided in association with the plurality of induction heating coils, and drives each induction heating coil, an expensive microcomputer having large storage capacity and high processing capacity needs to be used as the controller, in order that the single controller controls all of operation,
The present invention has been made in order to solve the above conventional problem.
An induction heating cooker of the present invention includes: a top plate for allowing a cooking container to be placed; and first and second induction heating units that are provided below the top plate, and inductively heat the cooking container.
Each of the first and second induction heating units includes: a plurality of induction heating coils; a plurality of inverters that individually drive the plurality of induction heating coils; a temperature detector that detects a temperature of the cooking container; and a power supply and controller that supplies power to the inverters, and controls the inverters in accordance with an output of the temperature detector.
In the first induction heating unit, the temperature detector has a first infrared sensor that is an only infrared sensor, and the first infrared sensor is provided in association with one of the induction heating coils provided at a foremost position. In the second induction heating unit, the temperature detector has a second infrared sensor that is an only infrared sensor, and the second infrared sensor is provided in association with one of the induction heating coils provided at a rearmost position.
According to the present invention, it is possible to configure a lower cost induction heating cooker enabling high accurate heating control by temperature detection with good responsiveness, in spite of a configuration in which heating control is performed by use of more expensive infrared sensors.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating a configuration of an induction heating cooker according to a first exemplary embodiment.
FIG. 2 is a schematic diagram illustrating a configuration of an induction heating cooker according to a second exemplary embodiment.
FIG. 3 is a schematic diagram illustrating a configuration of an induction heating cooker according to a third exemplary embodiment.
FIG. 4 is a schematic diagram of a conventional induction heating cooker.

DESCRIPTION OF EMBODIMENTS

A first aspect of the invention includes: a top plate for allowing a cooking container to be placed; and first and second induction heating units that are provided below the top plate, and inductively heat the cooking container.
Each of the first and second induction heating units includes: a plurality of induction heating coils; a plurality of inverters that individually drive the plurality of induction heating coils; a temperature detector that detects a temperature of the cooking container; and a power supply and controller that supplies power to the inverter, and controls the inverter in accordance with an output of the temperature detector.
In the first induction heating unit, the temperature detector has a first infrared sensor that is an only infrared sensor, and the first infrared sensor is provided in association with one of the induction heating coils provided at a foremost position. In the second induction heating unit, the temperature detector has a second infrared sensor that is an only infrared sensor, and the second infrared sensor is provided in association with one of the induction heating coils provided at a rearmost position.
According to the present invention, for example, in a case of an induction heating cooker in which each of the first and second induction heating units has two induction heating coils arranged at a front and a rear, and the first and second induction heating units are arranged on right and left sides, in the first induction heating unit, the infrared sensor is provided only in the front induction heating coil, and in the second induction heating unit, the infrared sensor is provided only in the rear induction heating coil.
A user simply uses the front induction heating coil of the first induction heating unit in sauteing cooking in which lifting operation of a cooking container is often performed, and simply uses the rear induction heating coil of the second induction heating unit in simmering cooking in which the lifting operation of the cooking container is hardly performed.
Thus, even a configuration, in which infrared sensors are not necessarily provided in association with all induction heating coils, does not cause any practical problem. Accordingly, according to the present invention, it is possible to configure a lower cost induction heating cooker enabling high accurate heating control by temperature detection with good responsiveness.
According to a second aspect of the invention, in the first aspect of the invention, the first induction heating unit is provided with the infrared sensor below the top plate, and the second induction heating unit is provided with the infrared sensor above the top plate and behind the one of the induction heating coils provided at the rearmost position.
According to the present invention, as to the second induction heating unit, the top plate or the like does not exist between the infrared sensor and the cooking container, and therefore there is less possibility that an infrared ray is attenuated before reaching the infrared sensor.
Additionally, as to the second induction heating unit, the infrared sensor is disposed at a further rear position with respect to the one of the induction heating coils located at the rearmost position, and therefore there is less possibility that other cooking container or the like is placed between the infrared sensor and the cooking container, and an infrared ray is blocked.
Accordingly, according to the induction heating cooker of the present invention, it is possible to more accurately perform temperature detection.
According to a third aspect of the present invention, in the first aspect of the invention, each of the power supply and controllers has a function of automatic cooking in which heating control is performed based on a predetermined sequence, one of the power supply and controllers in the first induction heating unit performs the automatic cooking by use of the one of the induction heating coils provided at the foremost position, and another of the power supply and controllers in the second induction heating unit performs the automatic cooking by use of the one of the induction heating coils provided at the rearmost position.
Additionally, the power supply and controllers are configured such that a control temperature for the automatic cooking in the second induction heating unit is lower than a control temperature for the automatic cooking in the first induction heating unit.
Generally, the sauteing cooking needs higher temperature heating than the simmering cooking. According to the present invention, the sauteing cooking, in which the lifting operation of the cooking container is often performed, and the high temperature heating is needed, can be performed by use of the front induction heating coil of the first induction heating unit.
The simmering cooking, in which the lifting operation of the cooking container is hardly performed, and lower temperature heating is performed compared to the sauteing cooking, can be performed by use of the rear induction heating coil of the second induction heating unit.
Accordingly, it is possible to configure a lower cost induction heating cooker having excellent operability and enabling high accurate heating control by temperature detection with good responsiveness.
Hereinafter, exemplary embodiments of the present invention are described with reference to drawings. In the following all drawings, the same or corresponding parts are denoted by the same reference numerals, and overlapped descriptions are omitted.

(FIRST EXEMPLARY EMBODIMENT)

FIG. 1 is a schematic diagram of an induction heating cooker according to a first exemplary embodiment of the present invention. With reference to FIG. 1, a configuration of induction heating cooker 1 according to this exemplary embodiment is described. In the following description, a side close to a user is represented as a front of induction heating cooker 1, and a side far from the user is represented as a rear of induction heating cooker 1.
As illustrated in FIG. 1, top plate 21 is configured by an electrical insulator such as glass and ceramic, and configures an upper surface of induction heating cooker 1, for allowing cooking containers 11 and 12 such as pans to be placed.
Induction heating coil 31, induction heating coil 32, induction heating coil 33, and induction heating coil 34 are formed in substantially the same shape, have the same configuration, and are disposed below top plate 21 in a matrix of two rows and two columns.
Power supply and controller 51 includes a DC power supply (not illustrated) for rectifying and smoothing power from a commercial AC power supply, and supplies power to inverter 41 and inverter 42. Additionally, power supply and controller 51 outputs a drive signal to inverter 41 to control inverter 41, and outputs a drive signal to inverter 42 to control inverter 42.
Power supply and controller 52 includes a DC power supply (not illustrated) for rectifying and smoothing power from a commercial AC power supply, and supplies power to inverter 43 and inverter 44. Additionally, power supply and controller 52 outputs a drive signal to inverter 43 to control inverter 43, and outputs a drive signal to inverter 44 to control inverter 44.
Inverter 41 receives the power and the drive signal from power supply and controller 51 to drive induction heating coil 31. Inverter 42 receives the power and the drive signal from power supply and controller 51 to drive induction heating coil 32.
Inverter 43 receives the power and the drive signal from power supply and controller 52 to drive induction heating coil 33. Inverter 44 receives the power and the drive signal from power supply and controller 52 to drive induction heating coil 34.
Infrared sensor 81 is a temperature detector configured from an InGaAs pin photodiode and the like, and is provided near induction heating coil 31, for example, below a clearance between winding wires located midway between a center and an outer periphery of annular induction heating coil 31.
Infrared sensor 81 receives an infrared ray emitted from cooking container 11 placed above induction heating coil 31 and entering through top plate 21, and outputs a voltage corresponding to a temperature of cooking container 11.
Similarly, infrared sensor 82 is a temperature detector configured from an InGaAs pin photodiode and the like, and is provided near induction heating coil 34, for example, below a clearance between winding wires located midway between a center and an outer periphery of annular induction heating coil 34.
Infrared sensor 82 receives an infrared ray emitted from cooking container 12 placed above induction heating coil 34 and entering through top plate 21, and outputs a voltage corresponding to a temperature of cooking container 12.
An advantage of using the infrared sensor is that thermal responsiveness is good compared to a case where the temperature of cooking container 11 (or 12) transferred through top plate 21 is detected by a thermistor or the like, and high accurate temperature control is possible.
In this exemplary embodiment, induction heating coils 31 and 32, inverters 41 and 42, power supply and controller 51, and infrared sensor 81 configure induction heating unit 61 equivalent to a first induction heating unit.
Induction heating coils 33 and 34, inverters 43 and 44, power supply and controller 52, and infrared sensor 82 configure induction heating unit 62 equivalent to a second induction heating unit.
In induction heating unit 61, only infrared sensor 81 is provided as a temperature detector. Infrared sensor 81 is provided in association with induction heating coil 31 located at a foremost position, among the induction heating coils included in induction heating unit 61.
In induction heating unit 62, only infrared sensor 82 is provided as a temperature detector. Infrared sensor 82 is provided in association with induction heating coil 34 located at a rearmost position, among the induction heating coils included in induction heating unit 62.
In this exemplary embodiment, infrared sensor 81 is equivalent to a first infrared sensor, and infrared sensor 82 is equivalent to a second infrared sensor.
In order to detect the temperatures of the cooking containers placed above induction heating coils 32 and 33, temperature sensors that are not infrared sensors, for example, thermistors may be provided in association with induction heating coils 32 and 33. In this case, power supply and controllers 51 and 52 control inverters 42 and 43 in accordance with outputs of the thermistors, respectively.
Each of power supply and controllers 51 and 52 has a function of automatic cooking in which heating control is performed based on a predetermined sequence. Infrared sensor 81 detects the temperature of cooking container 11 placed on induction heating coil 31, so that power supply and controller 51 performs automatic cooking.
Infrared sensor 82 detects the temperature of cooking container 12 placed on induction heating coil 34, so that power supply and controller 52 performs automatic cooking. In this case, a control temperature for automatic cooking by power supply and controller 52 is set to be lower than a control temperature for the automatic cooking by power supply and controller 51.
In this exemplary embodiment, induction heating cooker 1 has sauteing cooking and simmering cooking as an automatic cooking menu.
A control temperature for the sauteing cooking is, for example, a temperature selected from 140°C to 230°C. Power supply and controller 51 controls inverter 41 in accordance with a temperature detected by infrared sensor 81 such that cooking container 11 is maintained at the above control temperature.
Further, a control temperature for the simmering cooking is, for example, a temperature less than 100°C. Power supply and controller 52 controls inverter 44 in accordance with a temperature detected by infrared sensor 82 such that cooking container 12 is maintained at the above control temperature.
Therefore, a user simply uses front induction heating coil 31 of induction heating unit 61 in the sauteing cooking in which lifting operation of a frying pan is often performed, and simply uses rear induction heating coil 34 of induction heating unit 62 in the simmering cooking in which lifting operation of a pan is hardly performed.
Thus, even a configuration in which infrared sensors are not necessarily provided in association with all induction heating coils does not cause any practical problem. Accordingly, according to the present invention, it is possible to configure a lower cost induction heating cooker enabling high accurate heating control by temperature detection with good responsiveness.
In this exemplary embodiment, InGaAs pin photodiodes are used as infrared sensors 81 and 82. However, any components capable of detecting temperatures of bottom surfaces of cooking containers 11 and 12 by emitted infrared rays, such as silicon photodiodes and thermopiles, may be employed.
As described above, according to this exemplary embodiment, it is possible to configure a lower cost induction heating cooker enabling high accurate heating control by temperature detection with good responsiveness, in spite of a configuration in which heating control is performed by use of more expensive infrared sensors than thermistors.

(SECOND EXEMPLARY EMBODIMENT)

Hereinafter, a second exemplary embodiment of the present invention is described with reference to FIG. 2. FIG. 2 is a schematic diagram illustrating a configuration of an induction heating cooker according to this exemplary embodiment.
As illustrated in FIG. 2, induction heating cooker 2 has induction heating unit 61 disposed on a left side, and induction heating unit 63 disposed on a right side. Induction heating unit 63 includes induction heating coil 33, induction heating coil 34, inverter 43, inverter 44, infrared sensor 83, and power supply and controller 52.
Infrared sensor 83 is installed behind induction heating coil 34 and above top plate 21, receives an infrared ray emitted from cooking container 12 placed above induction heating coil 34, and outputs a voltage corresponding to a temperature of cooking container 12.
Power supply and controller 52 supplies power to inverters 43 and 44 to control inverter 43 and inverter 44. Additionally, infrared sensor 83 detects the temperature of cooking container 12 placed on induction heating coil 34, so that power supply and controller 52 performs automatic cooking in which heating control is performed based on a predetermined sequence.
In this exemplary embodiment, infrared sensor 81 is equivalent to the first infrared sensor, and infrared sensor 83 is equivalent to the second infrared sensor.
This exemplary embodiment is different from the first exemplary embodiment in that infrared sensor 83 is installed behind induction heating coil 34 and above top plate 21.
Infrared sensor 83 of this exemplary embodiment directly receives the infrared ray emitted from the cooking container not through the top plate that absorbs the infrared ray, and therefore can detect the temperature with high accuracy.
Further, in this exemplary embodiment, infrared sensor 83 is installed behind cooking container 12, namely, installed on a side far from a user of cooking container 12, and therefore there is less possibility that detection operation is obstructed by the user even when infrared sensor 83 is installed above top plate 21.
Proper use for these two installation places as to the infrared sensor is, for example, considered as follows.
The temperature of the bottom surface of cooking container 12 is higher than a temperature of a side surface of cooking container 12 due to self-heating by induction heating. Therefore, according to infrared sensor 82 installed below induction heating coil 34, as shown in the first exemplary embodiment, it is easy to measure a temperature of the hottest part of cooking container 12. Accordingly, infrared sensor 82 of the first exemplary embodiment is suitable for automatic cooking at a relatively high control temperature.
On the other hand, infrared sensor 83 installed behind induction heating coil 34 and above top plate 21, as shown in this exemplary embodiment detects the temperature of the side surface of cooking container 12. Therefore, infrared sensor 83 is not suitable for the automatic cooking at the relatively high control temperature compared to a case of the first exemplary embodiment.
However, infrared sensor 83 of this exemplary embodiment enables high accurate temperature detection as described above, and therefore is suitable for high accurate automatic cooking at a relatively low control temperature.
As a place of cooking container 12 whose temperature is detected by infrared sensor 83, for example, a side surface, to which heat of an inductively heated bottom is unlikely to be transferred, or a vicinity of a boundary between top plate 21 and cooking container 12 is conceived.
Particularly, in heating with high heating power, the temperature of the bottom surface of cooking container 12 is higher than a temperature of a cooking material inside cooking container 12 due to self-heating by induction heating.
However, when the temperature of the side surface of cooking container 12 is measured, the temperature can be detected with relatively less influence of self-heating in the bottom surface of cooking container 12, and the temperature of the cooking material can be detected with higher accuracy.
On the other hand, the vicinity of the boundary between cooking container 12 and top plate 21 often has a curved surface shape. Therefore, in a case where the temperature of the vicinity of the boundary between cooking container 12 and top plate 21 is measured, when this part is irradiated with an infrared ray in accordance with an ambient temperature that is a noise component, the infrared ray of the noise component is mostly reflected in a direction of top plate 21 due to the curved surface shape.
Top plate 21 has a high infrared ray emissivity (infrared ray emissivity = 1.0), and therefore the infrared ray reflected by cooking container 12 is almost absorbed. Accordingly, infrared sensor 83 does not detect the infrared ray of the noise component by the ambient temperature, and influence of noise is hardly received.
An infrared ray in accordance with heat transferred from cooking container 12 to top plate 21 due to heat conduction partially directly reaches infrared sensor 83 from top plate 21, and is partially reflected in the vicinity of the boundary between cooking container 12 and top plate 21 to reach infrared sensor 83.
Accordingly, even in a case where stainless steel or the like, a temperature of which is detected to be lower than an actual temperature only by the infrared ray that has a low infrared ray emissivity, and directly reaches from cooking container 12, is used as cooking container 12, the temperature of cooking container 12 is corrected by an infrared ray in accordance with heat transferred to top plate 21, and can be more accurately detected.
As described above, in this exemplary embodiment, infrared sensor 81 is provided below top plate 21 with respect to induction heating coil 31 disposed on a front, and infrared sensor 83 is provided above top plate 21 with respect to induction heating coil 34 disposed at a rear.
According to this exemplary embodiment, when induction heating coil 31 is used, cooking container 11 is easily lifted up and down, and automatic cooking (for example, sauteing cooking) at a relatively high control temperature can be performed.
When induction heating coil 34 is used, even with a configuration where infrared sensor 83 is provided above the top plate, it is possible to perform high accurate automatic cooking (for example, simmering cooking) at a relatively low control temperature without obstruction for temperature detection by infrared sensor 83.
In this exemplary embodiment, an InGaAs pin photodiode is used as infrared sensor 83. However, any components capable of detecting the temperature of the side surface of cooking container 12 by an emitted infrared ray, such as a silicon photodiode and a thermopile, may be employed.

(THIRD EXEMPLARY EMBODIMENT)

Hereinafter, a third exemplary embodiment of the present invention is described with reference to FIG. 3. FIG. 3 is a schematic diagram illustrating a configuration of induction heating cooker 3 according to this exemplary embodiment.
As illustrated in FIG. 3, induction heating cooker 3 has induction heating unit 64. Induction heating unit 64 includes induction heating coil 31, induction heating coil 34, inverter 41, inverter 44, infrared sensor 81, infrared sensor 83, and power supply and controller 53.
Power supply and controller 53 supplies power to inverters 41 and 44 to control inverter 41 and inverter 44.
Power supply and controller 53 has a function of automatic cooking in which a temperature of cooking container 11 placed above induction heating coil 31 is detected by infrared sensor 81, and heating control is performed based on a predetermined sequence. Similarly, power supply and controller 53 has a function of automatic cooking in which a temperature of cooking container 12 placed above induction heating coil 34 is detected by infrared sensor 83, and heating control is performed based on a predetermined sequence.
In this exemplary embodiment, infrared sensor 81 is equivalent to the first infrared sensor, and infrared sensor 83 is equivalent to the second infrared sensor.
This exemplary embodiment is different from the first and second exemplary embodiments in that induction heating unit 64 including two induction heating coils 31 and 34 is provided, and infrared sensors 81 and 83 are provided in association with induction heating coils 31 and 34 respectively.
Therefore, in a case of this exemplary embodiment, an expensive microcomputer having large storage capacity and high processing capacity needs to be used as power supply and controller 53 compared to a case of the first and second exemplary embodiments.
However, this exemplary embodiment is common to the second exemplary embodiment in that infrared sensor 81 is provided below top plate 21 with respect to induction heating coil 31 disposed on a front, and infrared sensor 83 is provided above top plate 21 with respect to induction heating coil 34 disposed at a rear.
Accordingly, according to this exemplary embodiment, when induction heating coil 31 is used, cooking container 11 is easily lifted up and down, and automatic cooking (for example, sauteing cooking) at a relatively high control temperature can be performed, similarly to the second exemplary embodiment.
Further, when induction heating coil 34 is used, even with a configuration where infrared sensor 83 is provided above the top plate, it is possible to perform high accurate automatic cooking (for example, simmering cooking) at a relatively low control temperature without obstruction for temperature detection by infrared sensor 83.

INDUSTRIAL APPLICABILITY

As described above, the present invention is applicable to an induction heating cooker for household or business use.

REFERENCE MARKS IN THE DRAWINGS

1, 2, 3 induction heating cooker
10, 11, 12 cooking container
20, 21 top plate
30, 31, 32, 33, 34 induction heating coil
40, 41, 42, 43, 44 inverter
50, 51, 52, 53 power supply and controller
61, 62, 63, 64 induction heating unit
80, 81, 82, 83 infrared sensor

Claims

An induction heating cooker comprising:
a top plate for allowing a cooking container to be placed; and

first and second induction heating units that are provided below the top plate, and inductively heat the cooking container, each of the first and second induction heating units including:
a plurality of induction heating coils;

a plurality of inverters that individually drive the plurality of induction heating coils;

a temperature detector that detects a temperature of the cooking container; and

a power supply and controller that supplies power to the inverters, and controls the inverters in accordance with an output of the temperature detector,

wherein

in the first induction heating unit, the temperature detector has a first infrared sensor that is an only infrared sensor, and the first infrared sensor is provided in association with one of the induction heating coils provided at a foremost position, and

in the second induction heating unit, the temperature detector has a second infrared sensor that is an only infrared sensor, and the second infrared sensor is provided in association with one of the induction heating coils provided at a rearmost position.
The induction heating cooker according to claim 1, wherein
the first induction heating unit is provided with the first infrared sensor below the top plate, and the second induction heating unit is provided with the second infrared sensor above the top plate and behind the one of the induction heating coils provided at the rearmost position.
The induction heating cooker according to claim 1, wherein
each of the power supply and controllers has a function of automatic cooking in which heating control is performed based on a predetermined sequence, one of the power supply and controllers in the first induction heating unit performs the automatic cooking by use of the one of the induction heating coils provided at the foremost position, and another of the power supply and controllers in the second induction heating unit performs the automatic cooking by use of the one of the induction heating coils provided at the rearmost position, and
the power supply and controllers are configured such that a control temperature for the automatic cooking in the second induction heating unit is lower than a control temperature for the automatic cooking in the first induction heating unit.