JP2021176124A - Induction heating cooker - Google Patents

Abstract

To prevent a large leakage magnetic field from being generated on the upper side of a top plate when a small cooking container having a diameter significantly smaller than the diameter of an induction heating coil is placed on the mounting surface of the top plate.SOLUTION: An induction heating cooker 10 is provided with small cooking container detecting means for detecting that a cooking container placed on a mounting surface 12a of a top plate 12 is a small cooking container, and in a case in which a high-frequency current is being supplied from a high-frequency current supply circuit 22 to an induction heating coil 20, when the small cooking container detecting means detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, a control unit 23 controls to change the output of the high-frequency current supplied from the high-frequency current supply circuit 22 to the induction heating coil 20 to a setting value lower than the rated output such that the magnetic field strength generated on the upper side of the top plate 12 becomes smaller than the upper limit value.SELECTED DRAWING: Figure 6

Description

In the present invention, the cooking container is heated by Joule heat generated by the electric resistance when an eddy current flows through a cooking container such as a pot placed on the upper side of the top plate, and the ingredients in the cooking container are cooked by induction heating. Regarding the cooker.

The following Patent Document 1 discloses an invention of an induction cooking device. The induction heating cooker is arranged in a casing having a top plate on which a cooking container such as a pot is placed on the mounting surface on the upper surface, and below the top plate at the upper part in the casing to heat the cooking container. An induction heating coil that generates an induction magnetic field, an inverter circuit that supplies a high-frequency current to the induction heating coil (high-frequency current supply circuit), and a high-frequency current that controls the power supply to the inverter circuit and supplies it to the induction heating coil. It is equipped with a control unit that controls the output. In this induction heating cooker, when a cooking utensil such as a pot is placed on the mounting surface of the top plate and a high-frequency current is supplied from the inverter circuit to the induction heating coil, an induced magnetic field is generated on the upper side of the top plate and the top is topped. Cooking containers such as pots placed on the upper side of the plate generate heat due to Joule heat generated by electrical resistance when a vortex current flows, and the ingredients placed in the cooking container such as pots are cooked in the heat-generating cooking container. ..

Japanese Unexamined Patent Publication No. 2011-090991

In the induction heating cooker described in Patent Document 1 described above, cooking utensils such as a pot are placed on the mounting surface on the upper surface of the top plate, and cooking is performed when a high-frequency current is supplied from the inverter circuit to the induction heating coil. Joule heat is generated in the container due to the electric resistance when the vortex current flows, and the foodstuffs put in the cooking container are cooked in the cooking container that generates heat. If the diameter of the cooking utensil placed on the mounting surface of the top plate is about the same as the diameter of the induction heating coil, the leakage magnetic field generated on the upper side of the top plate is small. However, this type of induction heating cooker is used in kitchens of restaurants, etc., and has an induction heating coil so that the entire bottom surface of a large cooking container such as a barrel can be heated uniformly. The diameter is also large. An inverter circuit is provided by placing, for example, a small cooking container having a diameter of less than half the diameter of the induction heating coil on the mounting surface of the top plate of the induction heating cooker having a large diameter of the induction heating coil. When a high-frequency current is supplied to the induction heating coil at a high output such as the rated output, there is a problem that the leakage magnetic field generated on the upper side of the top plate becomes large. According to the present invention, in an induction heating cooker, when a small cooking container having a diameter significantly smaller than the diameter of the induction heating coil is placed on the mounting surface of the top plate, a large leakage magnetic field is generated on the upper side of the top plate. The purpose is to prevent it from occurring.

In order to solve the above problems, the present invention presents a casing having a top plate on which a cooking container such as a pot is placed on the mounting surface on the upper surface, and an upper portion in the casing below the mounting surface of the top plate. An inductive heating coil that generates an inductive magnetic field to generate heat in the cooking container, a high-frequency current supply circuit that supplies a high-frequency current to the inductive heating coil, and an induction that controls the power supply to the high-frequency current supply circuit. It is an induction cooking cooker equipped with a control unit that controls the output of high-frequency current supplied to the heating coil, and is caused by the fact that the cooking container placed on the mounting surface of the top plate is smaller than the diameter of the induction heating coil. A small cooking container detecting means for detecting that the cooking container has a diameter smaller than the lower limit diameter, which is the lower limit diameter for generating a magnetic field exceeding a predetermined upper limit value, is provided on the upper side of the top plate, and a high-frequency current supply circuit is provided. When a small cooking container detecting means detects that the cooking container placed on the mounting surface of the top plate is a small cooking container while supplying a high-frequency current to the induction heating coil from the above, the control unit tops the top. The output of the high frequency current supplied from the high frequency current supply circuit to the induction heating coil was controlled to be changed to a set value set lower than the rated output so that the magnetic field strength generated on the upper side of the plate became smaller than the upper limit value. It is an object of the present invention to provide an induction cooking device characterized by the above.

In the induction heating cooker configured as described above, the cooking container placed on the mounting surface of the top plate exceeds a predetermined upper limit value on the upper side of the top plate due to being smaller than the diameter of the induction heating coil. When a small cooking container detecting means is provided to detect that the small cooking container has a diameter smaller than the lower limit diameter, which is the lower limit diameter for generating a magnetic field, and a high frequency current is supplied from the high frequency current supply circuit to the induction heating coil. In addition, when the small cooking container detecting means detects that the cooking container placed on the mounting surface of the top plate is a small cooking container, the control unit generates a smaller magnetic field strength on the upper side of the top plate than the upper limit value. Therefore, the output of the high-frequency current supplied from the high-frequency current supply circuit to the induction heating coil is controlled to be changed to a set value set lower than the rated output.

When a cooking container is placed on the upper side of the top plate and a high-frequency current is supplied to the induction heating coil from the high-frequency current supply circuit, the cooking container is affected by the electrical resistance when an eddy current flows due to the magnetic field generated on the upper side of the top plate. It generates heat. A diameter smaller than the lower limit diameter, which is the lower limit diameter for generating a magnetic field exceeding a predetermined upper limit value on the upper side of the top plate due to the fact that the cooking container placed on the upper side of the top plate is smaller than the diameter of the induction heating coil. In the case of a small cooking container, the leakage magnetic field generated on the upper side of the top plate becomes larger than the upper limit value. In this induction heating cooker, when the small cooking container detecting means detects that the cooking container placed on the mounting surface of the top plate is the small cooking container, the control unit is generated on the upper side of the top plate. Since the output of the high-frequency current supplied from the high-frequency current supply circuit to the induction heating coil was controlled to be changed to a set value set lower than the rated output so that the magnetic field strength became smaller than the upper limit value, the upper side of the top plate was controlled. It is possible to prevent the generation of a magnetic field exceeding the upper limit value.

As one embodiment of the induction cooking cooker configured as described above, when a magnetic field sensor for detecting a magnetic field generated on the upper side of the top plate is provided as a small cooking container detecting means, and the magnetic field sensor detects a magnetic field exceeding the upper limit value. It may be detected that the small cooking container is placed on the mounting surface. As another embodiment of the induction heating cooker, the top plate has a first temperature sensor at a position closer to the lower limit diameter from the center in the radial direction at a position aligned in the radial direction of the induction heating coil and a second temperature sensor at a position farther than the lower limit diameter. A temperature sensor is provided as a small cooking container detection means, and when the difference between the detection temperature of the first temperature sensor and the detection temperature of the second temperature sensor becomes equal to or more than a predetermined set temperature difference, the small cooking container is placed on the mounting surface. It may be detected.

As another embodiment of the induction heating cooker, the top plate has a first temperature sensor at a position closer to the lower limit diameter from the center in the radial direction at a position aligned in the radial direction of the induction heating coil and a second temperature sensor at a position farther than the lower limit diameter. The temperature sensor, the first and second temperature sensors, and the third temperature sensor are located at different positions in the circumferential direction of the induction heating coil, aligned in the radial direction of the induction heating coil, and closer to the lower limit diameter from the central part in the radial direction. A fourth temperature sensor is provided as a small cooking container detection means at a position far from the lower limit diameter, the difference between the detection temperature of the first temperature sensor and the detection temperature of the second temperature sensor, the detection temperature of the third temperature sensor, and the fourth temperature. Both the difference from the detection temperature of the temperature sensor is larger than 0, the detection temperature of the first temperature sensor and the detection temperature of the third detection temperature are the same temperature, and the detection temperature of the second temperature sensor and the fourth detection Temperature detection When the temperature is the same, it may be detected that the small cooking container is placed on the mounting surface. In this case, the control unit has an absolute value of the difference between the detection temperature of the first temperature sensor and the detection temperature of the third temperature sensor larger than 0, and the difference between the detection temperature of the second temperature sensor and the detection temperature of the fourth temperature sensor. The absolute value of is greater than 0, the detection temperature of the first temperature sensor and the detection temperature of the second temperature sensor are the same, and the detection temperature of the third temperature sensor and the detection temperature of the fourth temperature sensor are the same. At one point, the control unit detects that the cooking container is a small cooking container and is displaced from the center of the induction heating coil, and the control unit performs a high frequency so that the leakage magnetic field generated on the upper side of the top plate becomes smaller than the upper limit value. It is preferable to control so as to change the output of the high frequency current supplied from the current supply circuit to the induction heating coil to the set value.

As another embodiment of the induction heating cooker, the top plate is provided with a small infrared sensor that receives infrared rays radiated from the cooking container and transmitted through the top plate at a position farther than the lower limit diameter from the radial center of the induction heating coil. It is provided as a cooking container detection means so that it is detected that a small cooking container is placed on the mounting surface when the infrared wavelength received by the infrared sensor is the wavelength when the cooking container that generates heat is not arranged on the upper side. You may do it. Further, as another embodiment of the induction heating cooker, the top plate is radiated from the cooking container at different positions in the circumferential direction of the induction heating coil from the central portion in the radial direction to a position farther than the lower limit diameter and transmitted through the top plate. A plurality of infrared sensors that receive infrared rays are provided as small cooking container detection means, and the wavelength of the infrared rays received by at least one of the plurality of infrared sensors is small when the cooking container that generates heat is not arranged on the upper side. It may be detected that the cooking container is placed on the mounting surface.

As another embodiment of the induction heating cooker, the induction heating coil is provided with a first coil portion having a diameter smaller than the lower limit diameter and a second coil portion having a diameter larger than the lower limit diameter separately, and the first coil portion. A first current meter that measures the current flowing through the coil and a second current meter that measures the current flowing through the second coil are provided as small cooking container detection means, and the measured current of the first current meter and the measured current of the second current meter are provided. When the difference between the current and the current reaches a predetermined set value, it may be detected that the small cooking container is placed on the mounting surface. Further, as another embodiment of the induction heating cooker, a camera for acquiring an image of the upper side of the top plate is provided as a small cooking container detecting means, and the small cooking container is placed on the mounting surface based on the image acquired by the camera. It may be detected as a camera.

It is a perspective view of the induction heating cooker of 1st Embodiment. It is a vertical cross-sectional view which cut the central part in the left-right direction of the induction heating cooker of FIG. 1 along the front-rear direction. It is a perspective view which removed the top plate of the induction heating cooker of FIG. 1 and the front wall of a casing. It is a block diagram which shows the connection state of a control part and other equipment. FIG. 1A is a perspective view (a) corresponding to FIG. 1 when a large cooking container having the same size as the diameter of the induction heating coil is placed, and a small cooking container having a size approximately half the diameter of the induction heating coil. It is a perspective view (b) corresponding to FIG. 1 when it is placed. It is a flowchart which shows the control program which executes the control which adjusts the output of an inverter circuit by detecting that it is a small cooking container by the small cooking container detecting means. It is a plan view of the upper side of the top plate of the 2nd Embodiment. It is a flowchart corresponding to FIG. 6 of the 2nd Embodiment. It is a plan view of the upper side of the top plate of the third embodiment. It is a flowchart corresponding to FIG. 6 of the 3rd Embodiment. FIG. 5 is a schematic plan view corresponding to FIG. 9 when the small cooking container is placed so as to be displaced to the front side. It is a plan view of the upper side of the top plate of the 4th embodiment. It is a flowchart corresponding to FIG. 6 of 4th Embodiment. It is a plan view of the upper side of the top plate of the fifth embodiment. 6 is a flowchart corresponding to FIG. 6 of the fifth embodiment. It is a plan view of the upper side of the top plate of the sixth embodiment. It is a block diagram which shows the connection state of the control part of 6th Embodiment and other equipment. 6 is a flowchart corresponding to FIG. 6 of the sixth embodiment. It is a perspective view of the 7th embodiment. It is a flowchart corresponding to FIG. 6 of the 7th Embodiment.

Hereinafter, embodiments of the induction cooking device of the present invention will be described with reference to the accompanying drawings.
(First Embodiment)
As shown in FIGS. 1 to 3, the induction cooking device 10 of the first embodiment is installed in a kitchen or the like of a restaurant such as a restaurant, and is a cooking container such as a pot placed on the upper side of the top plate 12. Is heated to heat and cook the ingredients in a cooking container such as a pot. The induction heating cooker 10 has a casing 11 having a top plate 12 on which a cooking container such as a pot is placed on the mounting surface 12a on the upper surface, and an upper portion inside the casing 11 below the mounting surface 12a of the top plate 12. To the induction heating coil 20 which is arranged on the side and generates an induction magnetic field for heating the cooking container, the inverter circuit (high frequency current supply circuit) 22 which supplies a high frequency current to the induction heating coil 20, and the inverter circuit 22. It is provided with a control unit 23 that controls the power supply of the above and controls the output of the high frequency current supplied to the induction heating coil 20.

As shown in FIG. 1, the casing 11 of the induction heating cooker 10 has a substantially rectangular parallelepiped shape including the top plate 12. The top plate 12 is made of tempered glass, and the portion of the top plate 12 excluding the peripheral edge is a mounting surface 12a on which a cooking container such as a pot is placed. A mark portion 12b for placing a cooking container such as a pot is displayed on the mounting surface 12a of the top plate 12, and the mark portion 12b has a function of arranging the cooking container above the induction heating coil 20. doing. The mark portion 12b is a concentric representation of a plurality of circles having the same center as the induction heating coil 20, and the outermost circle of the mark portion 12b has substantially the same diameter as the diameter of the induction heating coil 20. It is sufficient that one or more circles are displayed on the mark portion 12b.

As shown in FIGS. 1 and 2, a back guard 13 extending upward is provided at the rear portion of the casing 11, and the back guard 13 discharges the exhaust gas discharged from the rear portion of the casing 11 to the upper side of the casing 11. It has a guiding function. Further, the back guard 13 is provided with a magnetic field sensor 14, and the magnetic field sensor 14 detects a magnetic field (leakage magnetic field) generated on the upper side of the top plate 12. The magnetic field sensor 14 of this embodiment is a small cooking container in which the cooking container placed on the mounting surface 12a of the top plate 12 is about half the diameter of the induction heating coil 20 (290 mm in this embodiment). It functions as a small cooking container detection means for detection.

When the cooking container placed on the mounting surface 12a of the top plate 12 is significantly smaller than the diameter of the induction heating coil 20 (290 mm in this embodiment), a large leakage magnetic field is generated on the upper side of the top plate 12. When a high-frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at a rated output, for example, the cooking container placed on the mounting surface 12a of the top plate 12 has a lower limit diameter of less than half the diameter of the induction heating coil 20 (this). In the case of a small cooking container having a diameter of 145 mm) or less in the embodiment, a magnetic field exceeding a predetermined upper limit of 5 A / m is generated on the upper side of the top plate 12. Therefore, when the magnetic field sensor 14 detects a magnetic field exceeding the upper limit of 5 A / m on the upper side of the top plate 12, it is detected that the small cooking container is placed on the upper side of the top plate 12.

As shown in FIGS. 2 and 3, an induction heating coil 20 is provided in the upper part of the casing 11. The induction heating coil 20 generates an induction magnetic field on the upper side of the top plate 12 when a high-frequency current is supplied from the inverter circuit 22, and eddy current is generated in a cooking container such as a pot placed on the mounting surface 12a of the top plate 12. Is generated by Joule heat generated by the electric resistance when an eddy current flows through the cooking container. The induction heating coil 20 is formed in a circular shape (annular shape), and is arranged concentrically with the mark portion 12b formed of a plurality of circles of the top plate 12. The bottom surface of cooking containers such as pots is often circular, and by placing the cooking container concentrically on the mark portion 12b on the mounting surface 12a of the top plate 12, the cooking container is placed on the induction heating coil 20. On the other hand, they will be arranged concentrically.

A main board 21 including an inverter circuit (high frequency current supply circuit) 22 for supplying a high frequency current to the induction heating coil 20 and a control unit 23 for controlling power supply to the inverter circuit 22 is provided in the lower part of the casing 11. ing. Under the control of the control unit 23, the inverter circuit 22 receives power sent from an external power source through the power cord 24 and supplies a high-frequency current to the induction heating coil 20.

As shown in FIG. 4, the control unit 23 is connected to the inverter circuit 22, and is also connected to various operation switches 15a of the operation panel 15 and the magnetic field sensor 14. The control unit 23 controls the amount of power supplied to the inverter circuit 22 (electric energy) by inputting operation signals from various operation switches 15a of the operation panel 15, and is supplied from the inverter circuit 22 to the induction heating coil 20. The output (current amount) of the high-frequency current is controlled.

Further, the control unit 23 has an upper limit value of 5 A / m, which defines that the cooking container mounted on the mounting surface 12a of the top plate 12 by the magnetic field sensor 14 as the small cooking container detecting means is a small cooking container. When the magnetic field of is detected, the output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is set to a set value lower than the rated output, and is controlled to be changed to half the rated output in this embodiment. However, the magnetic field strength generated on the upper side of the top plate 12 is set to be smaller than the upper limit of 5 A / m.

The operation of the induction cooking device 10 configured as described above will be described. Various types of operation panels 15 provided on the front surface of the casing 11 are placed on the mounting surface 12a on the upper surface of the top plate 12 so that cooking containers such as pots containing ingredients are arranged concentrically with the mark portion 12b. The operation switch 15a is operated to start cooking. The inverter circuit 22 is supplied with electric power transmitted from an external power source through the power strip 24, and the induction heating coil 20 is supplied with a high-frequency current from the inverter circuit 22. An induced magnetic field is generated on the upper side of the top plate 12 when a high-frequency current is supplied to the inductive heating coil 20, and a cooking container such as a pot placed on the upper side of the top plate 12 is affected by electrical resistance when an eddy current flows. Ingredients that generate heat due to Joule heat and are placed in a cooking container such as a pot are cooked by the heat-generating cooking container.

As shown in FIG. 5A, the outermost marker portion 12b in which the diameter of the cooking container such as a pot placed on the mounting surface 12a of the top plate 12 is displayed on the mounting surface 12a of the top plate 12 is displayed. When the placed cooking container is a large cooking container, such as when the size is substantially the same as the diameter of the induction heating coil 20, that is, 290 mm, which is substantially the same as the diameter of the induction heating coil 20, the induction heating coil 20 is connected from the inverter circuit 22. The magnetic field strength generated on the upper side of the top plate 12 is not high when a high-frequency current is supplied to the top plate 12. On the other hand, as shown in FIG. 5B, the diameter of the cooking container such as a pot placed on the mounting surface 12a on the upper surface of the top plate 12 is displayed on the mounting surface 12a of the top plate 12. The placed cooking container is a small cooking container, such as when the size is about half the diameter of the outermost mark portion 12b, that is, 145 mm or less, which is about half the size or less of the diameter of the induction heating coil 20. When is, the magnetic field strength generated on the upper side of the top plate 12 becomes high.

In the induction heating cooker 10, the control unit 23 executes the control program shown in FIG. 6 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 6, the control unit 23 repeatedly executes the process starting from step 101, and in step 101, various operation switches 15a of the operation panel 15 are operated, and the induction heating coil is operated from the inverter circuit 22. It is determined whether or not a high frequency current is supplied to 20. Unless the control unit 23 controls the induction heating coil 20 to supply a high-frequency current from the inverter circuit 22, the control unit 23 determines NO in step 101 and does not proceed to the control program in step 102.

The control unit 23 repeatedly determines NO in step 101 until the various operation switches 15a on the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, and the operation is performed. When the various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 101 and proceeds to step 102. In step 102, the control unit 23 determines whether or not the magnetic field detected by the magnetic field sensor 14 is larger than the upper limit value of 5 A / m. In the determination process according to step 102, the cooking container placed on the mounting surface of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A / on the upper side of the top plate 12. It is also a process of determining whether or not the small cooking container has a diameter smaller than the lower limit diameter, which is the lower limit diameter for generating a magnetic field exceeding m.

If the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost marker portion 12b as shown in FIG. 5A, the inverter circuit 22 Even if a high-frequency current is supplied to the induction heating coil 20 at the rated output, the magnetic field detected by the magnetic field sensor 14 does not exceed the upper limit of 5 A / m, and the control unit 23 determines NO in step 102. Return to step 101. When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in step 101. , The determination of NO is repeatedly executed in step 102. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 101 and prevents the control program from proceeding to step 102. become.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b). When a high-frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at the rated output, the magnetic field detected by the magnetic field sensor 14 becomes larger than the upper limit of 5 A / m, and the control unit 23 is set to YES in step 102. Is determined, and the process proceeds to step 103. In step 103, the control unit 23 changes the output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 to half the rated output. When a high frequency current of half the rated output is supplied to the induction heating coil 20 from the inverter circuit 22, and a high frequency current of half the rated output is supplied to the induction heating coil 20 above the top plate 12. An induced magnetic field is generated. A cooking container such as a pot placed on the upper side of the top plate 12 generates heat due to Joule heat due to electrical resistance when an eddy current flows when a high-frequency current is supplied to the induction heating coil 20 at half the rated output. Ingredients placed in a cooking container such as a pot are cooked by a cooking container that generates heat. Further, since the induction heating coil 20 is supplied with a high frequency current having an output half of the rated output from the inverter circuit 22, the magnetic field strength generated on the upper side of the top plate 12 is lower than the upper limit value of 5 A / m.

After changing the output from the inverter circuit 22 to the induction heating coil 20 to half the rated output in step 103, the control unit 23 executes the process starting from step 101 again, and determines YES in the determination process of step 101. After that, in step 102, it is determined again whether or not the magnetic field detected by the magnetic field sensor 14 is larger than the upper limit value of 5 A / m. Since the output of the high-frequency current supplied to the induction heating coil 20 is changed to be low in step 103, the detected magnetic field detected by the magnetic field sensor 14 is also smaller than the upper limit value of 5 A / m, and the control unit 23 receives the control unit 23. Based on the fact that the magnetic field detected by the magnetic field sensor 14 is smaller than the upper limit of 5 A / m, NO is determined in step 102 and the process returns to step 101.

When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the output changed low in step 103, the control unit 23 determines YES in step 101 and NO in step 102. The judgment is being executed repeatedly. When the various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 101 and cannot proceed to step 102. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, a large magnetic field can be prevented from being generated on the upper side of the top plate 12.

In the induction heating cooker 10 configured as described above, the cooking container placed on the mounting surface 12a of the top plate 12 is smaller than the diameter of the induction heating coil 20, so that the cooking container is placed on the upper side of the top plate 12. A small cooking container detecting means for detecting that the small cooking container has a diameter smaller than the lower limit diameter, which is the lower limit diameter for generating a magnetic field exceeding a predetermined upper limit value, is provided. In this embodiment, a magnetic field sensor 14 for detecting a magnetic field generated on the upper side of the top plate 12 is provided as a small cooking container detecting means, and when the magnetic field sensor 14 detects a magnetic field exceeding 5 A / m as an upper limit value, the small cooking container Is designed to detect that is placed on the mounting surface.

In the induction heating cooker 10, when the magnetic field sensor 14 detects a magnetic field exceeding 5 A / m as an upper limit and detects that the small cooking container is placed on the mounting surface, The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is rated as a set value lower than the rated output so that the magnetic field strength generated on the upper side of the top plate 12 is smaller than the upper limit of 5 A / m. It is controlled to change to half the output. As a result, when a high-frequency current was supplied from the inverter circuit 22 to the induction heating coil 20, a small cooking container having a lower limit diameter smaller than the diameter of the induction heating coil 20 was placed on the mounting surface 12a of the top plate 12. Therefore, it is possible to prevent a large leakage magnetic field from being generated on the upper side of the top plate 12.

(Second Embodiment)
As shown in FIG. 7, in the induction heating cooker 10 of the second embodiment, the induction heating coil 20 is arranged on the lower surface of the top plate 12 in the radial direction from the central portion in the radial direction from the lower limit diameter L described above. A first temperature sensor 16a is provided at a close position and a second temperature sensor 16b is provided at a position farther than the lower limit diameter L as a small cooking container detecting means.

In the induction heating cooker 10, when the temperature difference between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b becomes a predetermined temperature difference or more, the small cooking container is placed on the top plate 12. It is detected that it is placed on the surface 12a. When the control unit 23 detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, the magnetic field strength generated on the upper side of the top plate 12 is from 5 A / m, which is the upper limit value. The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is controlled to be changed to a set value lower than the rated output so as to be smaller. The induction heating cooker 10 of each of the following embodiments including the second embodiment is basically the same as the first embodiment described above except that the small cooking container detecting means is different. Hereinafter, the induction heating cooker 10 of the second embodiment in which the first and second temperature sensors 16a and 16b are provided as the small cooking container detecting means will be described in detail.

As described above, when the cooking container placed on the mounting surface 12a of the top plate 12 is significantly smaller than the diameter of the induction heating coil 20 (290 mm in this embodiment), a large leakage magnetic field is generated on the upper side of the top plate 12. .. When a high-frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at the rated output, the cooking container placed on the mounting surface 12a of the top plate 12 has a lower limit diameter L which is less than half the diameter of the induction heating coil 20 (this). In the case of a small cooking container having a diameter of 145 mm) or less in the embodiment, a magnetic field exceeding a predetermined upper limit of 5 A / m is generated on the upper side of the top plate 12. In the induction heating cooker 10 of the second embodiment, the first and second temperature sensors 16a and 16b are arranged in the radial direction of the induction heating coil 20 and are closer to the lower limit diameter L than the central portion of the induction heating coil 20. The first temperature sensor 16a is arranged at a position 70 mm from the central portion, and the second temperature sensor 16b is arranged at a position 80 mm from the central portion as a position farther than the lower limit diameter L from the central portion of the induction heating coil 20.

The first and second temperature sensors 16a and 16b are connected to the control unit 23, and the control unit 23 is an induction heating coil from the inverter circuit 22 based on the detected temperatures t1 and t2 of the first and second temperature sensors 16a and 16b. The output (current amount) of the high-frequency current supplied to the 20 is controlled. More specifically, the control unit 23 executes the control program shown in FIG. 8 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 8, in step 201, the control unit 23 determines whether or not the various operation switches 15a of the operation panel 15 are operated to supply a high frequency current from the inverter circuit 22 to the induction heating coil 20. judge. Unless the control unit 23 controls the induction heating coil 20 to supply a high-frequency current from the inverter circuit 22, the control unit 23 determines NO in step 201 and does not proceed to the control program in step 202.

The control unit 23 repeatedly determines NO in step 201 until the various operation switches 15a of the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, and the operation is performed. When various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 201 and proceeds to step 202. In step 202, the control unit 23 sets the temperature difference (t1-t2) between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b as a predetermined set temperature difference of, for example, 5 ° C. or more. Determine if it has become. In the determination process according to this step 202, the cooking container placed on the mounting surface 12a of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A on the upper side of the top plate 12. This is a process for determining whether or not the small cooking container has a diameter smaller than the lower limit diameter L, which is the lower limit diameter for generating a magnetic field exceeding / m.

If the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost mark portion 12b as shown in FIG. 5A, the first and the first Since the cooking container is arranged above the second temperature sensors 16a and 16b, the temperature difference (t1-t2) between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b is approximately 0 ° C. However, the temperature does not exceed 5 ° C., which is a predetermined set temperature difference, and the control unit 23 determines NO in step 202 and returns to step 201. When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in step 201. , The determination of NO is repeatedly executed in step 202. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 201 and prevents the control program from proceeding to step 202. become.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b). , The cooking container is arranged on the upper side of the first temperature sensor 16a, and the cooking container is not arranged on the upper side of the second temperature sensor 16b. The detection temperature t1 of the first temperature sensor 16a becomes a high temperature because the cooking container that generates heat is arranged on the upper side, whereas the detection temperature t2 of the second temperature sensor 16b does not have the cooking container that generates heat on the upper side. It becomes a low temperature. As a result, the temperature difference (t1-t2) between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b becomes, for example, 5 ° C. or more as a predetermined set temperature difference, and the control unit 23 steps. It is determined as YES in 202, and the process proceeds to step 203.

In step 203, the control unit 23 changes the output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 to half the rated output. When the induction heating coil 20 is supplied with the high frequency current from the inverter circuit 22 at an output lower than half of the rated output, the control unit 23 supplies the high frequency current without changing the output. The cooking container such as a pot placed on the upper side of the top plate 12 is Joule due to the electric resistance when the eddy current flows when the high frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at an output lower than half of the rated output. Ingredients that generate heat due to heat and are placed in a cooking container such as a pot are cooked by the heat-generating cooking container. Further, since the induction heating coil 20 is not supplied with a high frequency current having an output higher than half of the rated output from the inverter circuit 22, the magnetic field strength generated on the upper side of the top plate 12 should not exceed the upper limit value of 5 A / m. Become.

The control unit 23 changes the induction heating coil 20 from the inverter circuit 22 to supply a high-frequency current at an output lower than half of the rated output in step 203, and then executes the process starting from step 201 again. After the determination of YES in the determination process of step 201 and the determination of YES in the determination process of step 202, the control unit 23 continues the process of step 203 described above, and the induction heating coil 20 has an inverter circuit 22. A high-frequency current with an output higher than half of the rated output is not supplied from the inverter, and a leakage magnetic field exceeding the upper limit of 5 A / m is not generated on the upper side of the top plate 12. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 201 and cannot proceed to step 202. Will be. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

(Third Embodiment)
In the induction heating cooker 10 of the second embodiment, the first temperature sensor 16a and the lower limit diameter are located closer to the above-mentioned lower limit diameter L from the central portion in the radial direction at positions arranged in the radial direction of the induction heating coil 20 on the top plate 12. A second temperature sensor 16b is provided at a position farther than L as a small cooking container detecting means. As shown in FIG. 9, the induction heating cooker 10 of the third embodiment is the induction heating coil 20 at the rear part of the mounting surface 12a of the top plate 12, similarly to the induction heating cooker 10 of the second embodiment. A first temperature sensor 16a is provided at a position closer to the above-mentioned lower limit diameter L and a second temperature sensor 16b is provided at a position farther than the lower limit diameter L from the central portion in the radial direction at positions arranged in the radial direction of the above. The third temperature sensor 16c and the third temperature sensor 16c are located at different positions in the circumferential direction of the sensors 16a and 16b and the induction heating coil 20, at positions arranged in the radial direction of the induction heating coil 20, and at a position closer to the above-mentioned lower limit diameter L from the central portion in the radial direction. A second temperature sensor 16d is provided at a position farther than the lower limit diameter L. In this embodiment, the third and fourth temperature sensors 16c and 16d are located at different positions in the circumferential direction of the first and second temperature sensors 16a and 16b and the induction heating coil 20, and the first and second temperature sensors 16a and 16b are located. Is arranged at a diagonal position (opposite side position) with respect to the central portion of the induction heating coil 20.

In the induction heating cooker 10 of the third embodiment, the temperature difference between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b, and the detection temperatures t3 and the fourth of the third temperature sensor 16c. Both the temperature difference from the detection temperature t4 of the temperature sensor 16d is larger than 0, the detection temperature t1 of the first temperature sensor 16a and the detection temperature t3 of the third temperature sensor 16c are the same temperature, and the second temperature sensor When the detection temperature t2 of 16b and the detection temperature t4 of the fourth temperature sensor 16d are the same temperature, it is detected that the small cooking container is placed on the mounting surface. When the control unit 23 detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, the magnetic field strength generated on the upper side of the top plate 12 is from 5 A / m, which is the upper limit value. The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is controlled to be changed to a set value lower than the rated output so as to be smaller. Hereinafter, the induction heating cooker 10 of the third embodiment in which the first to fourth temperature sensors 16a to 16d are provided as the small cooking container detecting means will be described in detail.

In the induction heating cooker 10 of the third embodiment, the first and second temperature sensors 16a and 16b are arranged on the lower surface of the top plate 12 in the radial direction of the induction heating coil 20, and the central portion of the induction heating coil 20. The first temperature sensor 16a is placed 70 mm from the center as a position closer to the lower limit diameter L, and the second temperature sensor 16a is located 80 mm from the center as a position farther than the lower limit diameter L from the center of the induction heating coil 20. 16b is arranged. Further, on the lower surface of the top plate 12, the third and fourth temperature sensors 16c and 16d are placed at different positions in the circumferential direction of the first and second temperature sensors 16a and 16b and the induction heating coil 20 in the radial direction of the induction heating coil 20. The third temperature sensor 16c is arranged at a position 70 mm from the central portion as a position closer to the lower limit diameter L from the central portion of the induction heating coil 20, and is located farther than the lower limit diameter L from the central portion of the induction heating coil 20. The fourth temperature sensor 16d is arranged at a position 80 mm from the central portion. In this embodiment, the third and fourth temperature sensors 16c and 16d are positioned diagonally to the central portion as different positions in the circumferential direction of the first and second temperature sensors 16a and 16b, that is, the induction heating coil 20. Although they are arranged at different positions by 180 °, the present invention is not limited to this, and the positions may be at least 30 ° or more apart in the circumferential direction. Further, the third temperature sensor 16c is arranged from the central portion of the induction heating coil 20 at a position having the same length as the first temperature sensor 16a and closer to the lower limit diameter L, and the fourth temperature sensor 16d is arranged from the central portion of the induction heating coil 20. It has the same length as the second temperature sensor 16b and is arranged at a position farther than the lower limit diameter L.

The first to fourth temperature sensors 16a to 16d are connected to the control unit 23, and the control unit 23 is supplied to the induction heating coil from the inverter circuit 22 based on the detected temperatures of the first to fourth temperature sensors 16a to 16d. The output (current amount) of the high-frequency current is controlled. More specifically, the control unit 23 executes the control program shown in FIG. 10 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 10, in step 301, the control unit 23 determines whether or not the various operation switches 15a of the operation panel 15 are operated to supply a high frequency current from the inverter circuit 22 to the induction heating coil 20. If the determination is made and the high frequency current is not supplied from the inverter circuit 22 to the induction heating coil 20, it is determined as NO in step 301 and the control program cannot proceed to step 302.

The control unit 23 repeatedly determines NO in step 301 until the various operation switches 15a of the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, and the operation is performed. When various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 301 and proceeds to step 302. In step 302, the control unit 23 has a third temperature sensor in which the temperature difference between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b is higher than 0 ° C. (t1-t2> 0). The temperature difference between the detection temperature t3 of 16c and the detection temperature t4 of the fourth temperature sensor 16d is higher than 0 ° C. (t3-t4> 0), the detection temperature t1 of the first temperature sensor 16a and the detection temperature of the third temperature sensor 16c. It is determined whether or not t3 is the same (t1 = t3) and the detection temperature t2 of the second temperature sensor 16b and the detection temperature t4 of the fourth temperature sensor 16d are the same (t2 = t4). In the determination process according to this step 302, the cooking container placed on the mounting surface of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A / on the upper side of the top plate 12. This is a process for determining whether or not the small cooking container has a diameter smaller than the lower limit diameter L, which is the lower limit diameter for generating a magnetic field exceeding m.

When the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b), the first and the first The cooking container is arranged above the third temperature sensors 16a and 16c, and the cooking container is not arranged above the second and fourth temperature sensors 16b and 16d. The detection temperatures t1 and t3 of the first and third temperature sensors 16a and 16c are high because the cooking container that generates heat is arranged on the upper side, whereas the detection temperatures of the second and fourth temperature sensors 16b and 16d are high. Since the cooking container that generates heat is not arranged on the upper side, the temperatures of t2 and t4 are low. The temperature difference (t1-t2) between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b is higher than 0 ° C., and the detection temperature t3 of the third temperature sensor 16c and the fourth temperature sensor 16d The temperature difference (t3-t4) from the detection temperature t4 is higher than 0 ° C., the detection temperature t1 of the first temperature sensor 16a and the detection temperature t3 of the third temperature sensor 16c are the same (t1 = t3), and the second temperature. The detection temperature t2 of the sensor 16b and the detection temperature t4 of the fourth temperature sensor 16d are the same (t2 = t4), and the control unit 23 determines YES in step 302 and proceeds to step 303.

In step 303, the control unit 23 changes the output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 to half the rated output. When the induction heating coil 20 is supplied with the high frequency current from the inverter circuit 22 at an output lower than half of the rated output, the control unit 23 supplies the high frequency current without changing the output. After changing the induction heating coil 20 from the inverter circuit 22 so that the high frequency current is not supplied to the induction heating coil 20 at an output higher than half of the rated output, the process starting from step 301 is executed again. After the determination of YES in the determination process of step 301 and the determination of YES in the determination process of step 302, the control unit 23 continues the process of step 303 described above, and the induction heating coil 20 has an inverter circuit 22. High-frequency current with an output higher than half of the rated output is no longer supplied. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 301 and steps this control program. You will not be able to proceed to 302. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

Further, the condition of step 302 is satisfied because the small cooking container placed on the upper side of the top plate 12 is not arranged at the center of the induction heating coil 20 (not arranged concentrically with respect to the induction heating coil 20 and the mark portion 12b). It may not be. For example, as shown in FIG. 11, when the small cooking container is placed on the mounting surface 12a of the top plate 12 in front of the center of the induction heating coil 20 (one small cooking container is shown in FIG. 11). The small cooking container is not placed on the upper side of the first and second temperature sensors 16a and 16b (indicated by the chain line and marked with P), and the small cooking container is placed on the upper side of the third and fourth temperature sensors 16c and 16d. Is placed, the detection temperatures of the first and second temperature sensors 16a and 16b are about the same and lower, and the detection temperatures of the third and fourth temperature sensors 16c and 16d are about the same and higher. In this state, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, the conditions of t1-t2> 0, t3-t4> 0, t1 = t3 and t2 = t4 in step 302 are satisfied. Therefore, the control unit 23 determines NO in step 302 and proceeds to step 304.

In step 304, the control unit 32 has an absolute value (| t1-t3) of a temperature difference (t1-t3) between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t3 of the third temperature sensor 16c higher than 0 ° C. (| t1-). t3 |> 0), the absolute value of the temperature difference (t2-t4) between the detection temperature t2 of the second temperature sensor 16b and the detection temperature t4 of the fourth temperature sensor 16d is higher than 0 ° C. (| t2-t4 |> 0) ), The detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b are the same (t1 = t2), and the detection temperature t3 of the third temperature sensor 16c and the detection temperature t4 of the fourth temperature sensor 16d. Is the same (t3 = t4) or not.

As shown in FIG. 11, when the small cooking container is mounted on the mounting surface 12a of the top plate 12 on the front side of the center of the induction heating coil 20, the first and second temperature sensors 16a and 16b The small cooking container is not placed on the upper side of the above, and the small cooking container is placed on the upper side of the third and fourth temperature sensors 16c and 16d. Therefore, the detection temperatures of the first and second temperature sensors 16a and 16b are low to the same extent, and the detection temperatures of the third and fourth temperature sensors 16c and 16d are high to the same extent. The control unit 23 determines YES based on the fact that | t1-t3 |> 0, | t2-t4 |> 0, t1 = t2, and t3 = t4, and proceeds to step 303.

In step 303, the control unit 23 changes the output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 to half the rated output, and executes the process starting from step 301 again. After the determination of YES in the determination process of step 301, the determination of NO in the determination process of step 302, and the determination of YES in step 304, the control unit 23 continues the process of step 303 described above, and induces the process. The heating coil 20 is no longer supplied with a high-frequency current having an output higher than half of the rated output from the inverter circuit 22. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 301 and steps this control program. You will not be able to proceed to 302. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost mark portion 12b as shown in FIG. 5 (a). , The cooking container is arranged above the first to fourth temperature sensors 16a to 16d, and the detection temperatures t1 to t4 of the first to fourth temperature sensors 16a to 16d are high because the cooking container that generates heat is arranged above. It becomes the temperature. The temperature difference (t1-t2) between the detection temperature t1 of the first temperature sensor 16a and the detection temperature t2 of the second temperature sensor 16b is approximately 0 ° C., and the detection temperature t3 of the third temperature sensor 16c and the fourth temperature sensor 16d The temperature difference (t3-t4) from the detection temperature t4 is also approximately 0 ° C., and the control unit 23 determines NO in step 302 and proceeds to step 304.

Similarly, the cooking container is arranged above the first to fourth temperature sensors 16a to 16d, and the cooking container that generates heat at the detected temperatures t1 to t4 of the first to fourth temperature sensors 16a to 16d is arranged above. Since the temperature is high, | t1-t3 | = 0 and | t2-t4 | = 0, and the control unit 23 determines NO in step 304 and returns to step 301. With the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in the determination process of step 301, determines NO in the determination process of step 302, and steps 304. The determination of NO of is repeatedly executed. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 301 and does not proceed with this control program in step 302. Will be. In this way, only when the small cooking container is placed on the mounting surface 12a of the top plate 12, the output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is changed to half the rated output. , It is possible to prevent an excessive magnetic field from being generated on the upper side of the top plate 12.

(Fourth Embodiment)
As shown in FIG. 12, in the induction heating cooker 10 of the fourth embodiment, the cooking container is located below the top plate 12 at a position away from the radial center portion of the induction heating coil 20 and the lower limit diameter L. An infrared sensor 17a that receives infrared rays radiated from the top plate 12 and transmitted through the top plate 12 is provided as a small cooking container detecting means, and the wavelength of the infrared rays received by the infrared sensor 17a is generated when the cooking container is not arranged on the upper side. At this time, it is detected that the small cooking container is placed on the mounting surface 12a. When the control unit 23 detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, the magnetic field strength generated on the upper side of the top plate 12 is from 5 A / m, which is the upper limit value. The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is controlled to be changed to a set value lower than the rated output so as to be smaller. Hereinafter, the induction heating cooker 10 of the fourth embodiment provided with the infrared sensor 17a as the small cooking container detecting means will be described in detail.

The infrared sensor 17a is connected to the control unit 23, and the control unit 23 outputs a high frequency current (current amount) supplied from the inverter circuit 22 to the induction heating coil based on the temperature based on the infrared wavelength received by the infrared sensor 17a. ) Is controlled. More specifically, the control unit 23 executes the control program shown in FIG. 13 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 13, in step 401, the control unit 23 determines whether or not the various operation switches 15a of the operation panel 15 are operated to supply a high frequency current from the inverter circuit 22 to the induction heating coil 20. judge. Unless the control unit 23 controls the induction heating coil 20 to supply a high-frequency current from the inverter circuit 22, the control unit 23 determines NO in step 401 and does not proceed to the control program in step 402.

The control unit 23 repeatedly determines NO in step 401 until the various operation switches 15a of the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, and the operation is performed. When various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 401 and proceeds to step 402. In step 402, the control unit 23 determines whether or not the wavelength of the infrared rays received by the infrared sensor 17a is the wavelength when the cooking container that generates heat is not arranged on the upper side. In the determination process according to step 402, the cooking container placed on the mounting surface 12a of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A on the upper side of the top plate 12. This is a process for determining whether or not the small cooking container has a diameter smaller than the lower limit diameter L, which is the lower limit diameter for generating a magnetic field exceeding / m.

If the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost marking portion 12b as shown in FIG. 5A, the infrared sensor 17a Since the cooking container is arranged on the upper side of the above, the infrared wavelength received by the infrared sensor 17a becomes the wavelength when the cooking container that generates heat is arranged, and the control unit 23 determines NO in step 402 and determines in step 401. Return to. When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in step 401. , The determination of NO is repeatedly executed in step 402. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 401 and does not proceed with this control program to step 402. Will be.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b). Since the cooking container is not arranged on the upper side of the infrared sensor 17a, the infrared wavelength received by the infrared sensor 17a is the wavelength when the cooking container that generates heat is not arranged, and the control unit 23 determines YES in step 402. Then proceed to step 403. In step 403, the control unit 23 supplies a high-frequency current from the inverter circuit 22 to the induction heating coil 20 when the inverter circuit 22 supplies the high-frequency current to the induction heating coil 20 at an output higher than half of the rated output. Change the output of to half the rated output. When the induction heating coil 20 is supplied with the high frequency current from the inverter circuit 22 at an output lower than half of the rated output, the control unit 23 supplies the high frequency current without changing the output. The cooking container such as a pot placed on the upper side of the top plate 12 is Joule due to the electric resistance when the eddy current flows when the high frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at an output lower than half of the rated output. Ingredients that generate heat due to heat and are placed in a cooking container such as a pot are cooked by the heat-generating cooking container. Further, since the induction heating coil 20 is not supplied with a high frequency current having an output higher than half of the rated output from the inverter circuit 22, the magnetic field strength generated on the upper side of the top plate 12 should not exceed the upper limit value of 5 A / m. Become.

In step 403, the control unit 23 changes the induction heating coil 20 from the inverter circuit 22 so that the high frequency current is not supplied to the induction heating coil 20 at an output higher than half of the rated output, and then executes the process starting from step 401 again. After the determination of YES in the determination process of step 401 and the determination of YES in the determination process of step 402, the control unit 23 continues the process of step 403 described above, and the induction heating coil 20 has an inverter circuit 22. High-frequency current with an output higher than half of the rated output is no longer supplied. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 401 and steps this control program. You will not be able to proceed to 402. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

(Fifth Embodiment)
As shown in FIG. 12, in the induction heating cooker 10 of the fourth embodiment, the cooking container is located below the top plate 12 at a position separated from the radial center portion of the induction heating coil 20 by the lower limit diameter L. An infrared sensor 17a that receives infrared rays radiated from the top plate 12 and transmitted through the top plate 12 is provided as a small cooking container detecting means. As shown in FIG. 14, the induction heating cooker 10 of the fifth embodiment is located below the top plate 12 from the cooking container at a position away from the radial center portion of the induction heating coil 20 and the lower limit diameter L. Two (plural) infrared sensors 17b and 17c that receive infrared rays that are radiated and transmitted through the top plate 12 are provided as small cooking container detecting means.

In the induction cooking cooker 10, when the wavelength of the infrared rays received by at least one of the two infrared sensors 17b and 17c is the wavelength when the cooking container that generates heat is not arranged, the small cooking container is placed on the mounting surface. It is detected that it is placed on 12a. When the control unit 23 detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, the control unit 23 has an upper limit value of the magnetic field strength generated on the upper side of the top plate 12. The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is controlled to be changed to a set value lower than the rated output so as to be smaller than a certain 5 A / m. The infrared sensors 17b and 17c are arranged at diagonal positions so as to be on the front side and the rear side from the center of the induction heating coil 20, but the present invention is not limited to this, and the infrared sensors 17b and 17c can be used, for example. The induction heating coil 20 may be arranged at diagonal positions such as the left side and the right side from the center, or three or more infrared sensors may be arranged at positions away from the lower limit diameter L. good. Hereinafter, the induction heating cooker 10 of the fifth embodiment provided with the two infrared sensors 17b and 17c as the small cooking container detecting means will be described in detail.

The infrared sensors 17b and 17c are connected to the control unit 23, and the control unit 23 receives a high frequency current supplied from the inverter circuit 22 to the induction heating coil based on the temperature based on the infrared wavelength received by the infrared sensors 17b and 17c. The output (current amount) is controlled. More specifically, the control unit 23 executes the control program shown in FIG. 15 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 15, in step 501, the control unit 23 determines whether or not the various operation switches 15a of the operation panel 15 are operated to supply a high frequency current from the inverter circuit 22 to the induction heating coil 20. judge. Unless the control unit 23 controls the induction heating coil 20 to supply a high-frequency current from the inverter circuit 22, the control unit 23 determines NO in step 501 and does not proceed to the control program in step 502.

The control unit 23 repeatedly determines NO in step 501 until the various operation switches 15a of the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, and the operation is performed. When the various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 501 and proceeds to step 502. In step 502, the control unit 23 determines whether or not the wavelength of the infrared rays received by at least one of the infrared sensors 17b and 17c is the wavelength when the cooking container that generates heat is not arranged. In the determination process according to this step 502, the cooking container placed on the mounting surface 12a of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A on the upper side of the top plate 12. This is a process for determining whether or not the small cooking container has a diameter smaller than the lower limit diameter L, which is the lower limit diameter for generating a magnetic field exceeding / m.

If the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost mark portion 12b as shown in FIG. 5A, the infrared sensor 17a Since the cooking container is arranged on the upper side, the infrared wavelength received by both the infrared sensors 17b and 17c becomes the wavelength when the cooking container that generates heat is arranged on the upper side, and the control unit 23 is NO in step 502. Is determined and the process returns to step 501. When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in step 501. , The determination of NO is repeatedly executed in step 502. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 501 and does not proceed to the control program in step 502.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b). Since the cooking container is not arranged on the upper side of the infrared sensors 17b and 17c, the infrared wavelength received by both the infrared sensors 17b and 17c becomes the wavelength when the cooking container that generates heat is not arranged on the upper side, and the control unit 23 It is determined as YES in step 502, and the process proceeds to step 503. As shown in FIG. 11, when the small cooking container is arranged so as to be shifted to the front side or the rear side, the cooking container that generates heat of the received infrared wavelength is arranged on the upper side of the infrared sensors 17b and 17c. When there is no wavelength, the control unit 23 determines YES in step 502 and proceeds to step 503.

In step 503, the control unit 23 supplies a high-frequency current from the inverter circuit 22 to the induction heating coil 20 when the inverter circuit 22 supplies the high-frequency current to the induction heating coil 20 at an output higher than half of the rated output. Change the output of to half the rated output. When the induction heating coil 20 is supplied with the high frequency current from the inverter circuit 22 at an output lower than half of the rated output, the control unit 23 supplies the high frequency current without changing the output. The cooking container such as a pot placed on the upper side of the top plate 12 is Joule due to the electric resistance when the eddy current flows when the high frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at an output lower than half of the rated output. Ingredients that generate heat due to heat and are placed in a cooking container such as a pot are cooked by the heat-generating cooking container. Further, since the induction heating coil 20 is not supplied with a high frequency current having an output higher than half of the rated output from the inverter circuit 22, the magnetic field strength generated on the upper side of the top plate 12 should not exceed the upper limit value of 5 A / m. Become.

In step 503, the control unit 23 changes the induction heating coil 20 from the inverter circuit 22 so that the high frequency current is not supplied to the induction heating coil 20 at an output higher than half of the rated output, and then executes the process starting from step 501 again. After the determination of YES in the determination process of step 501 and the determination of YES in the determination process of step 502, the control unit 23 continues the process of step 503 described above, and the induction heating coil 20 has an inverter circuit 22. High-frequency current with an output higher than half of the rated output is no longer supplied. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 501 and cannot proceed to step 502. Will be. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

(Sixth Embodiment)
As shown in FIGS. 16 and 17, in the induction heating cooker 10 of the sixth embodiment, the induction heating coil 20 has a first coil portion 20a having a diameter smaller than the lower limit diameter L and a diameter larger than the lower limit diameter L. The second coil portion 20b is separately provided, and the inverter circuit 22 is provided with a first inverter circuit 22a that supplies a high frequency current to the first coil portion 20a and a second inverter circuit 22b that supplies a high frequency current to the second coil portion 20b. And have. Further, the induction heating cooker 10 measures the first ammeter 24a for measuring the current flowing from the first inverter circuit 22a to the first coil portion 20a and the current flowing from the second inverter circuit 22b to the second coil portion 20b. A second ammeter 24b is provided. In the induction heating cooker 10, the first and second coil portions 20a and 20b, the first and second inverter circuits 22a and 22b, and the first and second ammeters 24a and 24b are small cooking container detecting means. It is provided as.

In the induction heating cooker 10, when the difference between the measured current of the first ammeter 24a and the measured current of the second ammeter 24b reaches a predetermined set value, it is detected that the small cooking container is placed on the mounting surface. I am trying to do it. When the control unit 23 detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, the control unit 23 has an upper limit value of the magnetic field strength generated on the upper side of the top plate 12. The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is controlled to be changed to a set value lower than the rated output so as to be smaller than a certain 5 A / m. Hereinafter, the induction heating cooker 10 of the sixth embodiment in which the first and second coil portions 20a and 20b and the first and second ammeters 24a and 24b are provided as small cooking container detecting means will be described in detail.

As shown in FIG. 17, the first and second ammeters 24a and 24b are connected to the control unit 23, and the control unit 23 is an inverter based on the measured current values of the first and second ammeters 24a and 24b. The output (current amount) of the high-frequency current supplied from the circuit 22 (first and second inverter circuits 22a, 22b) to the induction heating coil 20 (first and second coil portions 20a, 20b) is controlled. More specifically, the control unit 23 executes the control program shown in FIG. 18 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 18, the control unit 23 determines in step 601 whether or not the various operation switches 15a of the operation panel 15 are operated to supply a high frequency current from the inverter circuit 22 to the induction heating coil 20. judge. Unless the control unit 23 controls the induction heating coil 20 to supply a high-frequency current from the inverter circuit 22, the control unit 23 determines NO in step 601 and does not proceed to the control program in step 602.

Until the various operation switches 15a on the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 repeatedly determines NO as NO in step 601 and operates the operation. When the various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 601 and proceeds to step 602. In step 602, the control unit 23 determines whether or not the difference (i1-i2) between the measured current i1 of the first ammeter 24a and the measured current i2 of the second ammeter 24b is higher than the set value. In the determination process according to step 602, the cooking container placed on the mounting surface 12a of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A on the upper side of the top plate 12. This is a process for determining whether or not the small cooking container has a diameter smaller than the lower limit diameter L, which is the lower limit diameter for generating a magnetic field exceeding / m.

If the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost marking portion 12b as shown in FIG. 5A, the first and the first Since the cooking container is arranged above the second coil portions 20a and 20b, the same current flows through the first and second coil portions 20a and 20b, and the measured currents i1 to the second ammeter of the first ammeter 24a flow. The difference (i1-i2) of the measured currents i2 of 24b does not become higher than the set value, and the control unit 23 determines NO in step 602 and returns to step 601. When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in step 601. , The determination of NO is repeatedly executed in step 602. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 601 and does not proceed with this control program in step 602. Will be.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b). , The cooking container is arranged on the upper side of the first coil portion 20a, and the cooking container is not arranged on the upper side of the second coil portion 20b. The amount of current flowing through the first coil unit 20a is larger than the amount of current flowing through the second coil unit 20b, and the difference (i1-i2) between the measured current i1 of the first ammeter 24a and the measured current i2 of the second ammeter 24b is large. The value becomes higher than the set value, and the control unit 23 determines YES in step 602 and proceeds to step 603. In step 603, when the control unit 23 supplies the high-frequency current from the inverter circuit 22 to the induction heating coil 20 at an output higher than half of the rated output, the control unit 23 supplies the high-frequency current from the inverter circuit 22 to the induction heating coil 20. Change the output of to half the rated output. When the induction heating coil 20 is supplied with the high frequency current from the inverter circuit 22 at an output lower than half of the rated output, the control unit 23 supplies the high frequency current without changing the output.

The cooking container such as a pot placed on the upper side of the top plate 12 is Joule due to the electric resistance when the eddy current flows when the high frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at an output lower than half of the rated output. Ingredients that generate heat due to heat and are placed in a cooking container such as a pot are cooked by the heat-generating cooking container. Further, since the induction heating coil 20 is not supplied with a high frequency current having an output higher than half of the rated output from the inverter circuit 22, the magnetic field strength generated on the upper side of the top plate 12 should not exceed the upper limit value of 5 A / m. Become. In this embodiment, the first and second inverter circuits 22a and 22b are controlled to supply a high frequency current to the first and second coil portions 20a and 20b at an output lower than half of the rated output. The present invention is not limited to this, and the supply of the high frequency current is stopped from the second inverter circuit 22b to the second coil portion 20b, and the high frequency current is supplied from the first inverter circuit 22a to the first coil portion 20b. Therefore, the magnetic field strength generated on the upper side of the top plate 12 may not exceed the upper limit value of 5 A / m.

In step 603, the control unit 23 changes the induction heating coil 20 from the inverter circuit 22 so that the high frequency current is not supplied to the induction heating coil 20 at an output higher than half of the rated output, and then executes the process starting from step 601 again. After the determination of YES in the determination process of step 601 and the determination of YES in the determination process of step 602, the control unit 23 continues the process of step 603 described above, and the induction heating coil 20 has an inverter circuit 22. High-frequency current with an output higher than half of the rated output is no longer supplied. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 601 and steps this control program. You will not be able to proceed to 602. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

(7th Embodiment)
As shown in FIG. 19, in the induction heating cooker 10 of the seventh embodiment, a camera 18 for acquiring an image of the upper side of the top plate 12 is provided as a small cooking container detecting means, and is based on the acquired image of the camera 18. It is detected that the small cooking container is placed on the mounting surface 12a. When the control unit 23 detects that the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container, the magnetic field strength generated on the upper side of the top plate 12 is from 5 A / m, which is the upper limit value. The output of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil 20 is controlled to be changed to a set value lower than the rated output so as to be smaller. The induction heating cooker 10 of the seventh embodiment in which the camera 18 is provided as the small cooking container detecting means will be described in detail below.

The camera 18 is connected to the control unit 23, and the control unit 23 controls the output (current amount) of the high-frequency current supplied from the inverter circuit 22 to the induction heating coil based on the acquired image of the camera 18. More specifically, the control unit 23 executes the control program shown in FIG. 20 so that the magnetic field strength generated on the upper side of the top plate 12 does not increase. As shown in FIG. 20, in step 701, the control unit 23 determines whether or not the various operation switches 15a of the operation panel 15 are operated to supply a high frequency current from the inverter circuit 22 to the induction heating coil 20. judge. Unless the control unit 23 is controlled to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines NO in step 701 and cannot proceed to this control program in step 702.

The control unit 23 repeatedly determines NO in step 701 until various operation switches 15a on the operation panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, and the operation is performed. When the various operation switches 15a on the panel 15 are operated to supply a high-frequency current from the inverter circuit 22 to the induction heating coil 20, the control unit 23 determines YES in step 701 and proceeds to step 702. In step 702, the control unit 23 determines whether or not the cooking container placed on the mounting surface 12a is a small cooking container based on the acquired image acquired by the camera 18. In the determination process according to step 702, the cooking container placed on the mounting surface 12a of the top plate 12 is smaller than the diameter of the induction heating coil 20, which is a predetermined upper limit of 5A on the upper side of the top plate 12. This is a process for determining whether or not the small cooking container has a diameter smaller than the lower limit diameter L, which is the lower limit diameter for generating a magnetic field exceeding / m.

If the cooking container placed on the mounting surface 12a of the top plate 12 is a large cooking container having substantially the same size as the outermost mark portion 12b as shown in FIG. 5A, the control unit 23 Determines NO in step 702 and returns to step 701. When a high-frequency current is being supplied from the inverter circuit 22 to the induction heating coil 20 with the large cooking container mounted on the mounting surface 12a of the top plate 12, the control unit 23 determines YES in step 701. , The determination of NO is repeatedly executed in step 702. When various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 701 and does not proceed with this control program in step 702. Will be.

On the other hand, when the cooking container placed on the mounting surface 12a of the top plate 12 is a small cooking container having a size of about half of the outermost mark portion 12b as shown in FIG. 5 (b). , The control unit 23 determines YES in step 702 and proceeds to step 703. In step 703, when the control unit 23 supplies the high-frequency current from the inverter circuit 22 to the induction heating coil 20 at an output higher than half of the rated output, the control unit 23 supplies the high-frequency current from the inverter circuit 22 to the induction heating coil 20. Change the output of to half the rated output. When the induction heating coil 20 is supplied with the high frequency current from the inverter circuit 22 at an output lower than half of the rated output, the control unit 23 supplies the high frequency current without changing the output. The cooking container such as a pot placed on the upper side of the top plate 12 is Joule due to the electric resistance when the eddy current flows when the high frequency current is supplied from the inverter circuit 22 to the induction heating coil 20 at an output lower than half of the rated output. Ingredients that generate heat due to heat and are placed in a cooking container such as a pot are cooked by the heat-generating cooking container. Further, since the induction heating coil 20 is not supplied with a high frequency current having an output higher than half of the rated output from the inverter circuit 22, the magnetic field strength generated on the upper side of the top plate 12 should not exceed the upper limit value of 5 A / m. Become.

In step 703, the control unit 23 changes the induction heating coil 20 from the inverter circuit 22 so that the high frequency current is not supplied to the induction heating coil 20 at an output higher than half of the rated output, and then executes the process starting from step 701 again. After the determination of YES in the determination process of step 701 and the determination of YES in the determination process of step 702, the control unit 23 continues the process of step 703 described above, and the induction heating coil 20 has an inverter circuit 22. High-frequency current with an output higher than half of the rated output is no longer supplied. In this state, when various operation switches 15a are operated and the supply of high-frequency current from the inverter circuit 22 to the induction heating coil 20 is stopped, the control unit 23 determines NO in step 701 and cannot proceed to step 702. Will be. In this way, even if the small cooking container is placed on the mounting surface 12a of the top plate 12, an excessive magnetic field can be prevented from being generated on the upper side of the top plate 12.

10 ... Induction heating cooker, 11 ... Casing, 12 ... Top plate, 12a ... Mounting surface, 14 ... Magnetic current sensor, 16a to 16d ... 1st to 4th temperature sensors, 17a to 17c ... Infrared sensor, 18 ... Camera, 20 ... Induction heating coil, 20a ... 1st coil section, 20b ... 2nd coil section, 21 ... Main board, 22 ... High frequency current supply circuit (inverter circuit), 23 ... Control section, 24a ... 1st ammeter, 24b ... Second ammeter.

Claims (9)

A casing with a top plate on which a cooking container such as a pot is placed on the mounting surface on the upper surface,
An induction heating coil that is arranged above the casing and below the mounting surface of the top plate to generate an induction magnetic field for heating the cooking container.
A high-frequency current supply circuit that supplies a high-frequency current to the induction heating coil,
An induction heating cooker including a control unit that controls the power supply to the high frequency current supply circuit and controls the output of the high frequency current supplied to the induction heating coil.
The lower limit of the diameter of the lower limit that causes the cooking container placed on the mounting surface of the top plate to generate a magnetic field exceeding a predetermined upper limit value on the upper side of the top plate due to being smaller than the diameter of the induction heating coil. A small cooking container detecting means for detecting that the cooking container has a diameter smaller than the diameter is provided.
When a high-frequency current is being supplied to the induction heating coil from the high-frequency current supply circuit, the small cooking container detecting means detects that the cooking container placed on the mounting surface of the top plate is the small cooking container. When you do
The control unit sets the output of the high-frequency current supplied from the high-frequency current supply circuit to the induction heating coil lower than the rated output so that the magnetic field strength generated on the upper side of the top plate becomes smaller than the upper limit value. An induction heating cooker characterized in that it is controlled to change to the set value. In the induction heating cooker according to claim 1,
A magnetic field sensor for detecting a magnetic field generated on the upper side of the top plate is provided as the small cooking container detecting means.
An induction heating cooker characterized in that when the magnetic field sensor detects a magnetic field exceeding the upper limit value, it is detected that the small cooking container is placed on the above-mentioned mounting surface. In the induction heating cooker according to claim 1,
On the top plate, a first temperature sensor is placed at a position closer to the lower limit diameter from the central portion in the radial direction at a position arranged in the radial direction of the induction heating coil, and a second temperature sensor is placed at a position farther than the lower limit diameter of the small cooking container. Provided as a detection means
When the difference between the detection temperature of the first temperature sensor and the detection temperature of the second temperature sensor becomes equal to or more than a predetermined set temperature difference, it is detected that the small cooking container is placed on the above-mentioned mounting surface. Induced heating cooker featuring. In the induction heating cooker according to claim 1,
The top plate has a first temperature sensor at a position closer to the lower limit diameter from the central portion in the radial direction at a position arranged in the radial direction of the induction heating coil, a second temperature sensor at a position farther than the lower limit diameter, and the first. The third temperature sensor and the lower limit diameter are located at different positions in the circumferential direction of the second temperature sensor and the induction heating coil, and at positions arranged in the radial direction of the induction heating coil from the central portion in the radial direction to a position closer to the lower limit diameter. A fourth temperature sensor is provided at a farther position as the small cooking container detecting means.
Both the difference between the detection temperature of the first temperature sensor and the detection temperature of the second temperature sensor and the difference between the detection temperature of the third temperature sensor and the detection temperature of the fourth temperature sensor are larger than 0. The small cooking when the detection temperature of the first temperature sensor and the detection temperature of the third detection temperature are the same temperature, and the detection temperature of the second temperature sensor and the detection temperature of the fourth detection temperature are the same temperature. An induction heating cooker characterized in that it is detected that the container is placed on the above-mentioned mounting surface. In the induction heating cooker according to claim 4.
In the control unit, the absolute value of the difference between the detection temperature of the first temperature sensor and the detection temperature of the third temperature sensor is larger than 0, and the absolute value of the difference between the detection temperature of the second temperature sensor and the detection temperature of the fourth temperature sensor. Is greater than 0, the detection temperature of the first temperature sensor and the detection temperature of the second temperature sensor are the same, and the detection temperature of the third temperature sensor and the detection temperature of the fourth temperature sensor are the same. When it is detected that the cooking container is a small cooking container and is displaced from the central portion of the induction heating coil,
The control unit changes the output of the high-frequency current supplied from the high-frequency current supply circuit to the induction heating coil to the set value so that the leakage magnetic field generated on the upper side of the top plate becomes smaller than the upper limit value. An induction heating cooker characterized by being controlled in such a manner. In the induction heating cooker according to claim 1,
The top plate is provided with an infrared sensor that receives infrared rays radiated from the cooking container and transmitted through the top plate at a position farther than the lower limit diameter from the central portion in the radial direction of the induction heating coil as the small cooking container detecting means. Provide,
When the wavelength of the infrared rays received by the infrared sensor is the wavelength when the cooking container that generates heat is not arranged on the upper side, it is detected that the small cooking container is placed on the above-mentioned mounting surface. A featured induction cooking device. In the induction heating cooker according to claim 1,
The top plate has a plurality of infrared sensors that receive infrared rays radiated from the cooking container and transmitted through the top plate at different positions in the circumferential direction of the induction heating coil from the central portion in the radial direction to a position far from the lower limit diameter. As the small cooking container detecting means,
Detects that the small cooking container is placed on the above-mentioned mounting surface when the wavelength of the infrared rays received by at least one of the plurality of infrared sensors is the wavelength when the cooking container that generates heat is not arranged on the upper side. Infrared cooker designed to do. In the induction heating cooker according to claim 1,
The induction heating coil is provided with a first coil portion having a diameter smaller than the lower limit diameter and a second coil portion having a diameter larger than the lower limit diameter separately, and a second coil portion for measuring a current flowing through the first coil portion. A 1 ammeter and a 2nd ammeter for measuring the current flowing through the 2nd coil portion are provided as the small cooking container detecting means.
When the difference between the measured current of the first ammeter and the measured current of the second ammeter reaches a predetermined set value, it is detected that the small cooking container is placed on the above-mentioned mounting surface. Induction heating cooker. In the induction heating cooker according to claim 1,
A camera for acquiring an image of the upper side of the top plate is provided as the small cooking container detecting means.
An induction heating cooker characterized in that it is detected that the small cooking container is placed on the above-mentioned mounting surface based on an image acquired by the camera.

Images