JP2013033758A - Induction heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating apparatus which reliably detects boiling over and controls heating power depending on the quantity of the boiling over.SOLUTION: An induction heating apparatus comprises: a top plate on which a cooking vessel is placed; a substantially circular heating coil generating an induction field for heating the cooking vessel; a heating control part controlling heating power of the cooking vessel by controlling a high frequency current supplied to the heating coil; a plurality of arc-shaped electrodes arranged on an undersurface of the top plate along an edge of the heating coil; and capacitance detection means detecting a change in capacitance produced in the electrodes caused by adherence of a cooked object to the top plate. When the capacitance detection means detects a change of capacitance in at least two electrodes among the plural electrodes, the heating control part controls heating power so that the heating power is reduced or stopped thereby to reliably detect boiling over.

Description

  The present invention relates to an induction heating device used in general homes, restaurants, offices, and the like.

  Conventionally, in this type of induction heating device, the capacitance changes by covering the electrode placed on the lower surface of the top plate with the cooking container or the food spilled from the cooking container. A detection method is disclosed (for example, see Patent Document 1).

JP 2008-159494 A

  However, the conventional configuration has problems such as large variations in detection accuracy due to the size of the cooking container and the shape and arrangement of the electrodes. In addition, when the capacitance changes due to a factor other than spilling, it may be erroneously detected as spilling.

  An object of this invention is to provide the induction heating apparatus which can detect reliably.

  In order to solve the conventional problems, an induction heating apparatus according to the present invention supplies a top plate on which a cooking container is placed, a heating coil that generates an induction magnetic field to heat the cooking container, and the heating coil. A heating control unit that controls the heating power of the cooking container by controlling high-frequency current, an electrode disposed on the lower surface of the top plate, and a capacitance generated in the electrode due to the object to be cooked adhering to the top plate There is a capacitance detecting means for detecting a change, and when the capacitance detecting means detects that there is a change in the capacitance, the heating control unit controls the heating power to be reduced or stopped. In the induction heating apparatus to be performed, the electrodes are arranged along the edge of the heating coil, so that it is possible to reliably detect spillage.

  According to the induction heating device of the present invention, it is possible to reliably detect spillage.

The block block diagram of the induction heating apparatus of Embodiment 1 of this invention Arrangement configuration diagram of electrodes in induction heating device of embodiment 1 of the present invention Arrangement configuration diagram of electrodes in induction heating apparatus of embodiment 6 of the present invention Arrangement configuration diagram of electrodes in induction heating apparatus of embodiment 8 of the present invention Arrangement configuration diagram of electrodes in induction heating device of embodiment 9 of the present invention Arrangement configuration diagram of electrodes in induction heating apparatus of embodiment 10 of the present invention Arrangement configuration diagram of electrodes in induction heating apparatus of embodiment 11 of the present invention Arrangement configuration diagram of electrodes in induction heating apparatus of embodiment 12 of the present invention The other arrangement block diagram of the electrode in the induction heating apparatus of Embodiment 12 of this invention

  1st invention controls the high frequency electric current supplied to the top plate which mounts a cooking vessel, the induction coil which generates an induction magnetic field in order to heat a cooking vessel, and the heating coil, and the heating electric power of a cooking vessel A heating control unit for controlling, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to a food to be cooked on the top plate. When the capacitance detecting means detects that there is a change in capacitance, the heating control unit controls the heating power to be reduced or stopped, and the electrode is By using the induction heating device arranged along the edge of the heating coil, the food to be cooked spilled from the cooking container can be detected immediately.

  In a second aspect of the invention, a top plate on which the cooking container is placed, a heating coil that generates an induction magnetic field to heat the cooking container, and a high-frequency current supplied to the heating coil are controlled to increase the heating power of the cooking container. A heating control unit for controlling, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to a food to be cooked on the top plate. When the capacitance detecting means detects that there is a change in capacitance, the heating control unit controls the heating power to be reduced or stopped by the heating control unit, wherein the electrodes are fan-shaped. By using an induction heating device that has a circular arc shape with a radial length shorter than the arc length, it is possible to reliably detect spillage even when the electrode area is small. Kill.

  3rd invention controls the high frequency electric current supplied to the top plate which mounts a cooking vessel, the induction coil which generate | occur | produces an induction magnetic field in order to heat a cooking vessel, and supplies the heating electric power of a cooking vessel A heating control unit for controlling, a plurality of electrodes arranged on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrodes due to the food to be cooked on the top plate. And an induction heating device that controls the heating power to be reduced or stopped by the heating control unit when the capacitance detecting means detects that there is a change in capacitance with at least two electrodes. By doing so, it is possible to reliably detect spillage.

  4th invention controls the heating power of a cooking vessel by controlling the high frequency current supplied to the top plate which mounts a cooking vessel, the induction coil which generates an induction magnetic field in order to heat a cooking vessel, and the heating coil A heating control unit for controlling, a plurality of electrodes arranged on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrodes due to the food to be cooked on the top plate. Control of the heating control unit when the capacitance detecting means detects that the capacitance has changed with two or more electrodes and when the capacitance change is detected with one electrode. By using an induction heating device that changes the contents, the amount of spillage can be detected, and control according to the amount can be performed.

  According to a fifth aspect of the present invention, when the capacitance detection means detects a change in capacitance with two or more electrodes, the amount by which the heating power is reduced is smaller than when a change in capacitance is detected with one electrode. By using the induction heating device according to claim 4 to be increased, it is possible to suppress the spilling without reducing the required minimum heating power that does not continue spilling, and without reducing the quality of cooking.

6th invention controls the high frequency electric current supplied to the top plate which mounts a cooking vessel, the induction coil which generates an induction magnetic field in order to heat a cooking vessel, and the heating coil, and the heating power of a cooking vessel A heating control unit for controlling, a plurality of electrodes arranged on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrodes due to the food to be cooked on the top plate. And an induction heating device that controls the heating power to be reduced or stopped by the heating control unit when the capacitance detecting means detects that there is a change in the capacitance. By using an induction heating device in which the two electrodes are arranged at different distances from the center of the heating coil, it is possible to cope with spillage in cooking containers of different sizes. Kill.

  In the seventh invention, the capacitance detection means first detects the change in capacitance of the electrode closer to the center of the heating coil, and then the capacitance of the electrode farther from the center of the heating coil. By using the induction heating apparatus according to claim 6 that controls to reduce or stop the heating power when a change is detected, it is possible to reliably detect spillage.

  In the eighth aspect of the invention, the capacitance detecting means detects the change in capacitance of the electrode closer to the center of the heating coil first, and then the electrode farther from the center of the heating coil within a predetermined time. The induction heating device according to claim 7, wherein control is performed such that heating power is reduced or stopped when a change in capacitance is detected, so that the capacitance does not change due to factors other than spillage. Can be detected.

  According to a ninth aspect of the invention, there is provided an induction heating device according to claim 6, wherein the center of the edge direction of at least two electrodes is arranged so as not to be aligned on a straight line from the center of the heating coil. Variations in detection due to differences can be reduced.

  In a tenth aspect of the present invention, a top plate on which the cooking container is placed, a heating coil that generates an induction magnetic field to heat the cooking container, and a high-frequency current supplied to the heating coil are controlled to increase the heating power of the cooking container. A heating control unit for controlling, an electrode disposed on the lower surface of the top plate, a capacitance detecting means for detecting a change in capacitance generated in the electrode due to attachment of an object to be cooked on the top plate, and storage A setting value stored in the storage means and a change amount of the capacitance detected by the capacitance detection means, and the control content of the heating control unit is changed based on the comparison result By using the induction heating device that performs this, it is possible to detect the amount of spillage and perform control according to the amount.

  In the eleventh aspect of the invention, the set value stored in the storage means is compared with the amount of change in capacitance detected by the capacitance detection means, and the case where the change in capacitance is larger than the set value is smaller. The induction heating device according to claim 10, wherein the amount of heating power is reduced more than in the case, so that the minimum amount of heating power that does not continue to spill over is suppressed, and the spillage is reduced without dropping the cooking result. Can be stopped.

  In a twelfth aspect of the present invention, a top plate on which the cooking container is placed, a plurality of heating coils that generate an induction magnetic field to heat the cooking container, and heating of the cooking container by controlling the high-frequency current supplied to the heating coil. A heating control unit for controlling electric power, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to the food to be cooked on the top plate. And an induction heating device that controls the heating power to be reduced or stopped by the heating control unit when the capacitance detecting means detects that there is a change in capacitance, By using an induction heating device disposed between the heating coils, it is possible to detect spillage with a small number of electrodes.

A thirteenth aspect of the present invention is to heat a cooking container by controlling a top plate on which the cooking container is placed, a plurality of heating coils that generate an induction magnetic field to heat the cooking container, and a high-frequency current supplied to the heating coil. A heating control unit for controlling electric power, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to the food to be cooked on the top plate. And an induction heating device that controls the heating power to be reduced or stopped by the heating control unit when the capacitance detecting means detects that there is a change in capacitance, Can be made less susceptible to the influence of noise due to a strong electric field by using an induction heating device arranged individually between the heating coils.

  In a fourteenth aspect of the invention, a top plate on which the cooking container is placed, a plurality of heating coils that generate an induction magnetic field to heat the cooking container, and heating of the cooking container by controlling the high-frequency current supplied to the heating coil. A heating control unit for controlling electric power, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to the food to be cooked on the top plate. And an induction heating device that controls the heating power to be reduced or stopped by the heating control unit when the capacitance detecting means detects that there is a change in capacitance, By using an induction heating device arranged at the shortest distance from the outer circumference of each of the heating coils, it is possible to detect spillage with a small number of electrodes.

  In a fifteenth aspect of the invention, a top plate on which the cooking container is placed, a heating coil that generates an induction magnetic field to heat the cooking container, and a high-frequency current supplied to the heating coil are controlled to increase the heating power of the cooking container. A heating control unit for controlling, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to a food to be cooked on the top plate. When the electrostatic capacity detecting means detects that there is a change in the electrostatic capacity, the heating control unit controls the heating power to be reduced or stopped so that the user can perform heating. An operation unit for instructing the state is further provided, and the electrode is an induction heating device disposed between the center of the heating coil and the operation unit, so that the spilled food is placed in the operation unit. It is possible to prevent scolded.

  In a sixteenth aspect of the invention, a top plate on which the cooking container is placed, a heating coil that generates an induction magnetic field to heat the cooking container, and a high-frequency current supplied to the heating coil are controlled to increase the heating power of the cooking container. A heating control unit for controlling, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to a food to be cooked on the top plate. When the capacitance detecting means detects a change in capacitance, the heating control unit controls the heating power to be reduced or stopped by the heating control unit, the heating control unit And an intake port for sucking in air for cooling, etc., and the electrode is an induction heating device disposed between the center of the heating coil and the intake port. Can the foods that Fukikobore from entering the air inlet.

  In a seventeenth aspect of the invention, a top plate on which the cooking container is placed, a heating coil that generates an induction magnetic field to heat the cooking container, and a high-frequency current supplied to the heating coil to control the heating power of the cooking container A heating control unit for controlling, an electrode disposed on the lower surface of the top plate, and a capacitance detecting means for detecting a change in capacitance generated in the electrode due to a food to be cooked on the top plate. When the capacitance detecting means detects a change in capacitance, the heating control unit controls the heating power to be reduced or stopped by the heating control unit, the heating control unit An exhaust port for exhausting air used for cooling, etc., and the electrode is an induction heating device disposed between the center of the heating coil and the exhaust port. Can the foods that Fukikobore from entering the exhaust port.

  According to an eighteenth aspect of the present invention, in order to avoid the influence at the time of induction heating, the thickness of the electrode is made thinner than the skin depth determined from the operating frequency at the time of induction heating, thereby eliminating the influence at the time of induction heating and detecting spillage. A possible induction heating device can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a block diagram of an induction heating apparatus according to a first embodiment of the present invention. The induction heating apparatus of the present embodiment includes a top plate 2 on which a cooking container 1 for heating a cooked product is placed, a heating coil 3 that generates an induction magnetic field to heat the cooking container 1, and a commercial power source. An inverter circuit 7 that converts the power of the power supply and supplies a high-frequency current to the heating coil 3, and a heating control unit 4 that controls the inverter circuit 7 to control the heating power of the cooking vessel 1.

  The electrode 5 is configured on the lower surface of the top plate 2, and a capacitance detecting means 6 for detecting a change in capacitance between the electrode 5 and another conductor is connected to the heating control unit 4 to control heating. The unit 4 controls the inverter circuit 7 in accordance with the result of the capacitance detection means 6 to change the high-frequency current supplied to the heating coil 3 so that the heating power of the cooking vessel 1 is controlled.

  The cooking container 1 is a container in which to-be-cooked items such as ingredients are placed, and is a pan, a frying pan, a kettle or the like, and can be heated by induction heating.

  The cooking vessel 1 is placed on a top plate 2 that forms part of the outline of the induction heating device. At that time, the cooking container 1 is placed at a position facing the heating coil 3. The top plate 2 often uses crystallized glass, but is not limited thereto.

  The heating coil 3 is supplied with a high-frequency current from an inverter circuit 7 that operates according to an instruction from the heating control unit 4, and generates a high-frequency magnetic field by the current. An eddy current is generated in the cooking vessel 1 that has received the high-frequency magnetic field, and the cooking vessel 1 is heated by the eddy current.

  FIG. 2 is a diagram showing the arrangement of electrodes according to the first embodiment of the present invention.

  In FIG. 2, the heating coil 3 is wound coarsely and densely and a gap is provided in the middle. However, the present invention is not limited to this. Moreover, the heating coil 3 does not need to be circular, and may be elliptical or rectangular.

  As shown in FIG. 2, the electrode 5 is arranged along the edge of the heating coil 3, and is configured to cover a wide range so that an object to be cooked is likely to be placed on the electrode regardless of where the cooking container 1 is spilled. It is possible to detect the spillage immediately. Moreover, when the heating coil 3 is wound densely as shown in FIG. 2, it is possible to immediately detect the spillage even in the cooking container 1 having a small diameter by providing an electrode in the gap portion like the electrode 5b. However, in this case, since it is affected by noise due to induction heating, there is a possibility that the capacitance cannot be normally detected. Therefore, measures such as strengthening noise countermeasures may be necessary. The reason for arranging the electrode 5 in this way is that when the cooking container 1 is placed at the center of the heating coil 3, the food to be spilled from the cooking container 1 often spreads around the heating coil 3. This is because if the electrodes are arranged widely along the edge of the heating coil 3, it is easy to detect spillage.

  Furthermore, since the electrode 5 is easily affected by a strong electric field when the area is increased, the area of the electrode 5 cannot be increased too much. The same applies to a closed loop configuration. Therefore, it is desirable to arrange the heater coil 3 along the edge of the heating coil 3 in order to make it possible to detect a large amount of spillage in the smallest possible area.

The heating control unit 4 is connected to an operation unit 8 and an inverter circuit 7 for a user of the induction heating device to instruct heating power and the like. For example, when the automatic cooking mode is instructed by the operation unit 8, the heating control unit 4 controls the inverter circuit 7 according to the content of the automatic cooking. In addition, even when the user starts or stops heating or adjusts the heating power from the operation unit 8, the heating control unit 4 controls the inverter circuit 7 so as to perform a desired operation. is there.

  The electrode 5 is a conductor formed on the lower surface of the top plate 2 by application or adhesion, and forms a capacitor with the conductor on the top plate 2. Normally, there is nothing on the top plate 2, so air plays its role. However, when another object such as the cooking container 1, fingers, water, or an object to be cooked is on the top plate 2, the capacitance changes because the relative permittivity of each object is different from that of air. This change in capacitance is detected by the capacitance detection means 6. The electrostatic capacity detection means 6 often detects a change in electrostatic capacity by converting it into a change in DC voltage, but is not limited thereto.

  In addition, the electrode 5 is comprised by the shape thinner than the skin depth determined from the operating frequency at the time of an induction heating cooking appliance performing induction heating. By making the electrode 5 thinner than the skin depth, the generation of eddy currents inside the electrode 5 due to the influence of the magnetic field generated when the cooking vessel 1 is induction-heated can be suppressed, and the capacitance change detection due to spilling can be prevented. Generation of an unnecessary electric field can be suppressed.

  About the induction heating apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the user instructs the start of heating through the operation unit 8, the heating control unit 4 operates the inverter circuit 7 to supply a high-frequency current to the heating coil 3. Thereby, a high frequency magnetic field is generated from the heating coil 3 and heating of the cooking vessel 1 is started.

  The heating control unit 4 controls the inverter circuit 7 so that the heating power set by the user is obtained by operating the operation unit 8. Specifically, for example, an input current of the inverter circuit 7 is detected, and the detected value is input to the heating control unit 4. The heating control unit 4 compares the thermal power set by the user with the input current of the inverter circuit 7 and changes the operation state of the inverter circuit 7. By repeating such an operation, the heating control unit 4 operates to control the heating power set by the user and maintain the heating power.

  When the cooking container 1 is heated in this way, the cooking object in the cooking container 1 may reach the boiling point, and the cooking object may be spilled out of the cooking container 1. At that time, if the heating is continued without reducing the heating power, the cooking object spills from the cooking vessel 1 one after another, and the operation unit 8 is hot and cannot be operated due to the operation unit 8. There is a possibility that problems such as being unable to clean due to the food to be cooked will occur. In addition, the food to be cooked spilled from the cooking container 1 onto the top plate 2 may stick to the top plate 2 when heat is applied.

  Therefore, in the present invention, when a change in the capacitance detected by the capacitance detecting means 6 is detected, the heating power is reduced or the heating is stopped to prevent the spilling from continuing, so that the food to be cooked is the top plate. 2 is an induction heating device that does not stick to 2.

  When the heating coil 3 is circular as shown in FIG. 2, when an electrode is arranged along the edge of the heating coil 3, a fan-shaped arc shape is formed. As shown in FIG. 2, the arc shape is wide without making the area too large by making the radial length (that is, the width of the electrode 5) shorter than the arc direction length (that is, the length of the electrode 5). The electrode shape can correspond to the spillage in the range (ie, the angle from the center of the heating coil 3), and the spillage can be detected more quickly and reliably.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, the induction heating apparatus has a plurality of electrodes, and the capacitance detecting means controls to reduce or stop the heating power when a change in capacitance is detected by the plurality of electrodes. It is.

  As described above, when the object to be cooked is spilled from the cooking container 1, it cannot be predicted which part of the cooking container 1 will be spilled. Therefore, if the outer periphery is surrounded along the edge of the heating coil 3, the possibility that the food to be spilled on the electrode 5 will be covered increases, but the outer periphery cannot be surrounded because it is easily affected by a strong electric field. For this reason, it is impossible to dispose an electrode having a very large area.

  In the case of the small electrode 5, for example, even when the food to be cooked pops out and falls on the electrode 5 while cooking the fried food, the capacitance changes, and it is mistakenly detected that it is spilled. May reduce cooking performance.

  In this way, it is difficult to determine whether or not a small electrode is spilled even when the capacitance changes.

  Therefore, in the present invention, a plurality of electrodes are arranged, and when the capacitance detection means 6 detects a change in capacitance with the plurality of electrodes and reliably detects that the spill is over, the heating power is reduced, Control to stop spilling. This reduces the amount of food to be spilled and prevents the food from being stuck to the top plate 2 and becoming difficult to clean. In this embodiment, two electrodes are provided. However, when three or more electrodes are provided and a change in capacitance is detected by two or more of the electrodes, heating is performed as if it is surely detected that the spill is over. You may make it perform control which reduces electric power and stops a spill.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, the heating control unit has a plurality of electrodes, and the capacitance detection means detects a change in capacitance with a plurality of electrodes and detects a change in capacitance with one electrode. The induction heating device changes the control content.

  When there is a change in capacitance in a plurality of electrodes, it is possible to reliably detect that there is a spill. However, if heating is continued without reducing the heating power until there is a change in capacitance between the plurality of electrodes, there is a possibility that the amount of food to be spilled will increase. Therefore, when a change in capacitance is detected with a plurality of electrodes, a spill occurs with a high probability, and when a change in capacitance is detected with one electrode, there is a possibility that the spill may occur. The control unit 4 can reduce the amount of spillage by performing control corresponding to each situation.

  As the control content, when the capacitance detection means 6 detects a change in capacitance with a plurality of electrodes 5, the amount by which the heating power is reduced is smaller than when a change in capacitance is detected with one electrode 5. When it is certain that it is spilled, the heating power will be reduced to control the spillage reliably, and in the case of one electrode that may spill, the rate of spilling will be reduced. Therefore, control such as reducing the heating power can be considered.

  In this embodiment, two electrodes are provided. However, when three or more electrodes are provided and a change in capacitance is detected by two or more electrodes, a change in capacitance is detected by one electrode 5. The control may be performed such that the amount by which the heating power is reduced is larger than that when detecting.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, the plurality of electrodes 5 are induction heating devices arranged such that the distances from the center of the heating coil 3 are different.

  As already described, when the diameter of the cooking container 1 changes, it may take time for the spilled food to spread over the electrode 5.

  Therefore, when arranging a plurality of electrodes as shown in FIG. 2, by changing the distance from the center of the heating coil 3, even if the cooking container 1 has a different diameter, it can be spilled more quickly. It becomes possible to detect.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, the capacitance detecting means 6 first detects a change in the capacitance of the electrode 5 closer to the center of the heating coil 3, and then statically moves the electrode 5 farther from the center of the heating coil 3. This is an induction heating device that performs control so as to reduce or stop the heating power when a change in electric capacity is detected.

  When the diameter of the cooking container 1 is small, the to-be-cooked food spills out from the edge of the cooking container 1 and spreads outward. Therefore, when a plurality of electrodes are arranged at different distances from the center of the heating coil 3 as shown in FIG. 2, the object to be cooked covers the electrode 5b near the center of the heating coil 3, and then the electrode 5a. Should cover the top.

  Therefore, if a change in capacitance is not detected in that order, there is a possibility that a phenomenon other than spilling may have occurred. Therefore, the heating control unit 4 should not perform control to prevent erroneous detection. Can do. In addition, when each electrode 5 has a long time to detect a change in capacitance, there is a possibility that the capacitance has changed due to a factor other than the spill over even if the detection order is the same as that at the time of spill over. Therefore, it is desirable to perform control as a spill if a change in capacitance is detected from an electrode near the center of the heating coil 3 within a predetermined time.

  Although the predetermined time varies depending on the configuration and arrangement of the electrodes, for example, when there is an interval of 5 seconds or more, it is considered that there is no continuous spilling. It is considered that the predetermined time is preferably determined experimentally by generating a continuous spill.

(Embodiment 6)
Next, a sixth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

In the present invention, the induction heating device is arranged such that the center in the edge direction of each electrode is shifted from the center of the heating coil so as not to be aligned on one straight line.

  As already explained, when the food to be spilled from the cooking container 1, it cannot be predicted from which direction the spill will occur. When arranging a plurality of electrodes so as to be able to cope with the occurrence of spilling from any direction, it is possible to arrange the electrodes by shifting them so that the centers of the electrodes 5 are not aligned on one straight line as shown in FIG. Therefore, the possibility of being able to cope with the occurrence of spillage increases, and the accuracy of detection of spillage can be increased.

(Embodiment 7)
Next, a seventh embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, there is a storage means, the set value stored in the storage means is compared with the amount of change in capacitance detected by the capacitance detection means, and the control of the heating control unit is performed based on the comparison result. This is an induction heating device that changes the contents.

  The capacitance of the electrode 5 varies depending on the relative dielectric constant of the object to be cooked covering the electrode 5, the area covering the electrode 5, and the like. In particular, the difference in the area covering the electrode 5 is also related to the amount of food to be cooked and can be important information for control after detection.

  When the cooking object covers the electrode 5 widely, the change in capacitance is large, and when the amount covering the electrode 5 is small, the change in capacitance is small. The amount of food to be cooked can be determined.

  The storage means 9 is for storing a predetermined value, and there may be one or a plurality of predetermined values. The storage means 9 may be rewritable or non-rewritable like a flash memory. In addition, the storage unit 9 may be a part of the heating control unit 4. For example, a ROM area or a flash area of the heating control unit 4 such as a microcomputer or a DSP may be the storage unit 9.

  When the change in capacitance is detected by the capacitance detection means 6, the heating control section 4 compares the predetermined value stored in the storage means 9 connected to the heating control section 4 and determines the control content. For example, heating is stopped when the change in capacitance is larger than a predetermined value, and the heating power is decreased when the change in capacitance is smaller than a predetermined value. When there is a large change in capacitance, the amount of food to be spilled is large, so heating is stopped to stop spilling quickly, and when the change in capacitance is small, In some cases, the amount is small, and it is possible to stop the spilling even by slightly reducing the heating power. If the heating power is reduced more than necessary, the heating power will be reduced if the boiling power is maintained and the cooking power is weakened, which may cause adverse effects such as reduced cooking performance. It is desirable to keep the spillage to the minimum necessary so that it does not continue. As in the present invention, if the amount of heating power to be reduced is determined according to the amount of food to be spilled, it is possible to minimize spillage without reducing cooking performance, and it is easy to clean and easy to use. A good induction heating device can be realized.

(Embodiment 8)
Next, an eighth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, an induction heating apparatus having a plurality of heating coils and electrodes arranged between the respective heating coils is used.

  FIG. 4 is an arrangement configuration diagram of electrodes. Induction heating devices range from those having only one heating coil to those having a plurality of heating coils. In FIG. 4, an induction heating apparatus having three heating ports has three heating coils because all three heating ports are heated by induction heating. Many types in which the heating port farthest away from the operation unit 8 is a radiant heater are also widely used. In the present invention, description is made assuming that all the heating ports are of the induction heating system, but other heating systems may be used.

  When spilling occurs, the food to be cooked spreads around the cooking container 1 and spreads toward other heating ports. There may be other cooking at the other heating port, and if the temperature of the top surface of the top plate 2 is high, the spilled food will stick to the top plate 2 and it will take time to clean. There is a possibility.

  In order to prevent such a situation from occurring, by disposing the electrode 5 between the respective heating coils 3, it is possible to prevent the spilled food from spreading to the adjacent heating port. Furthermore, if the electrodes 5 arranged between the respective heating coils are connected as shown in FIG. 4, only one capacitance detecting means 6 is required, and the construction can be made inexpensively.

(Embodiment 9)
Next, a ninth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, the induction heating apparatus has a plurality of heating coils, and the electrodes are individually arranged between the respective heating coils.

  If the area of the electrode 5 is increased, it cannot be correctly detected due to the influence of a strong electric field. In such a case, by arranging the electrodes 5 between the respective heating coils 3 as shown in FIG. 5, it is possible to detect the spilled food without increasing the area. However, in this case, it is necessary for the capacitance detection means 6 to detect the capacitance change of the three electrodes 5, but it is easier to guess from which heating port the spilled out than the example of FIG.

(Embodiment 10)
Next, a tenth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, an induction heating apparatus having a plurality of heating coils and electrodes arranged at the approximate center of each heating coil is used.

  In an induction heating apparatus having a plurality of heating ports, in order to make the number of capacitance detection means 6 as small as possible, the electrodes 5 are at the shortest distance from the outer periphery of each heating coil as shown in FIG. If it arrange | positions to a position, the to-be-cooked item spilled from each heating port can be detected.

  However, in the case of the present embodiment, the distance between the center of each heating coil 3 and the electrode 5 becomes long. Therefore, when the cooking container 1 is small, it is detected that the spilled food has not spread sufficiently. I can't. That is, it takes a long time from the occurrence of spillage to the detection.

In order to detect the spillage early, the configuration of the eighth embodiment is desirable, but the configuration of the present embodiment is the lowest cost and easy to implement. Therefore, it is necessary to change the configuration of the electrode 5 depending on cost, ease of implementation, or certainty of detection of spillage and time taken for detection.

(Embodiment 11)
Next, an eleventh embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the present invention, the user has an operation unit for instructing the heating state, and the electrode is an induction heating device disposed between the center of the heating coil and the operation unit.

  The operation unit 8 of the induction heating apparatus is often disposed on the front surface of the device or the top plate 2 that is the upper surface of the device. When arranged on the top plate 2, there is a case where there is a frame that supports the top plate 2 between the operation unit 8 and the top plate 2, and an electrode is arranged on the lower surface of the top plate 2 to change the capacitance. It is roughly divided into the operation unit 8 used. When there is a frame, a level difference is generated, so it is rare that the cooking object spilled from the cooking container 1 covers the operation unit 8, but the capacitance is changed by arranging an electrode on the lower surface of the top plate 2. In the case of the operation unit 8 using the above, since there is no step difference from the top plate 2, the spilled food may cover the operation unit 8. In such a case, since the spilled food is high temperature, the heating power is reduced, or even if the operation unit 8 is operated to stop the heating, there is a high temperature food to be cooked or burned. There is also a possibility.

  In order to prevent such a situation, the electrode 5 is disposed between the center of the heating coil 3 and the operation unit 8 as shown in FIG. Thus, the heating control part 4 reduces heating electric power, and can implement | achieve the induction heating apparatus which can be used safely. In addition, although it is desirable to arrange | position the electrode 5 between the edge of the heating coil 3, and the operation part 8, it is not limited to it.

  The electrode 5 may be disposed along the edge of the heating coil 3 as in the electrode 5a, or may be in a straight line as in the electrode 5b.

(Embodiment 12)
Next, a twelfth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the induction heating device, since the inverter circuit 7 and the heating coil 3 in the device generate heat, cooling is often performed to prevent the device from being damaged. As a cooling method, a method of sending air to the heat generating portion by a cooling fan is often used. In that case, an air intake port through which the cooling fan takes in air from the outside and an air exhaust port through which warm air after cooling is discharged to the outside are required.

  If the spilled food enters the intake and exhaust ports, cleaning is not easy, so it is necessary to prevent the spilled food from entering.

  Therefore, the electrode 5 is disposed between the center of the heating coil 3 and the air inlet 10 as shown in FIG. 8, or is disposed between the center of the heating coil 3 and the air outlet 11 as shown in FIG. By detecting and reducing the heating power by the heating control unit 4, it is possible to prevent the object to be cooked from entering the air inlet 10 and the air outlet 11. The electrode 5 is preferably disposed between the edge of the heating coil 3 and the intake port 10 or the exhaust port 11, but is not limited thereto.

  As described above, the induction heating device according to the present invention reliably detects the spilled food by arranging the electrodes so as not to hinder the operation of the equipment and the cleaning performance, and the spilled food. By controlling the heating power according to the amount of food to be cooked, it is possible to prevent the spilling from continuing while maintaining cooking performance, and it is easy to clean, and induction heating used in general households etc. Useful for equipment.

DESCRIPTION OF SYMBOLS 1 Cooking container 2 Top plate 3 Heating coil 4 Heating control part 5, 5a, 5b Electrode 6 Capacitance detection means 7 Inverter circuit 8 Operation part 9 Memory | storage means 10 Intake port 11 Exhaust port

Claims (14)

A top plate on which the cooking vessel is placed, a substantially circular heating coil that generates an induction magnetic field to heat the cooking vessel, and heating that controls the heating power of the cooking vessel by controlling the high-frequency current supplied to the heating coil A controller, a plurality of arc-shaped electrodes arranged along the edge of the heating coil on the lower surface of the top plate, and a capacitance generated in the electrodes by the object to be cooked on the top plate A capacitance detecting means for detecting a change, and when the capacitance detecting means detects that the capacitance has changed in at least two of the plurality of electrodes, the heating control section An induction heating apparatus that controls to reduce or stop the heating power. Among the plurality of electrodes, the capacitance detection means detects when there is a change in capacitance with two or more electrodes and when the change in capacitance is detected with one electrode. The induction heating apparatus according to claim 1, wherein the control content of the heating control unit is changed. The amount by which the heating power is decreased when the capacitance detection unit detects a change in capacitance with two or more electrodes than when a change in capacitance is detected with one electrode. 2. The induction heating device according to 2. The induction heating apparatus according to claim 1, wherein at least two of the plurality of electrodes are arranged such that distances from a center of the heating coil are different. The capacitance detecting means detects a change in capacitance of the electrode farther from the center of the heating coil after detecting a change in capacitance of the electrode closer to the center of the heating coil first. The induction heating apparatus according to claim 4, wherein control is performed so that the heating power is reduced or stopped in some cases. After the capacitance detecting means first detects the change in capacitance of the electrode closer to the center of the heating coil, the capacitance of the electrode farther from the center of the heating coil within a predetermined time is detected. The induction heating apparatus according to claim 5, wherein control is performed so that the heating power is reduced or stopped when a change is detected. The induction heating apparatus according to claim 4, wherein centers of edge directions of at least two electrodes are arranged so as not to be aligned on a straight line from the center of the heating coil. And a storage unit for changing the control content of the heating control unit based on a comparison result between the set value stored in the storage unit and the amount of change in capacitance detected by the capacitance detection unit. Item 2. The induction heating device according to Item 1. The set value stored in the storage means is compared with the amount of change in capacitance detected by the capacitance detection means, and the case where the change in capacitance is larger than the set value is smaller than the case where the change is smaller. The induction heating apparatus according to claim 8, wherein the heating power is reduced by a large amount. The induction heating apparatus according to claim 1, further comprising a plurality of heating coils, wherein the electrode is disposed between the plurality of heating coils. The induction heating apparatus according to claim 1, further comprising an operation unit for a user to instruct a heating state, wherein the electrode is disposed between a center of the heating coil and the operation unit. The induction heating apparatus according to claim 1, further comprising an air inlet for sucking air for cooling the heating control unit and the like, wherein the electrode is disposed between a center of the heating coil and the air inlet. . The induction heating according to claim 1, further comprising an exhaust port for discharging air used for cooling of the heating control unit and the like, wherein the electrode is disposed between a center of the heating coil and the exhaust port. apparatus. The induction heating apparatus according to claim 1, wherein the thickness of the electrode is made thinner than the skin depth determined from the operating frequency during induction heating in order to avoid the influence during induction heating.