JP5083273B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that heats an object to be heated using electromagnetic induction.

  Conventionally, in this type of induction heating cooker, in Patent Document 1, the capacitance changes by covering the electrode placed on the lower surface of the top plate with the cooking container and the ingredients spilled from the cooking container. Overflow is detected and heating control is performed (see, for example, Patent Document 1).

JP 2008-159494 A

  In practice, it is not uncommon to heat a pan without a lid as the object to be heated, but in this case, the phenomenon that the object to be cooked scatters outside the pot due to active boiling is often seen. The conventional induction heating cooker described in Patent Document 1 detects the spillage of the food to be cooked by observing the capacitance change of the scattered electrodes and controlling the heating amount. Therefore, it is necessary to control the heating each time the electrode is applied, which hinders cooking and has a problem that it is not useful for practical use.

  In other words, the spillage that requires automatic heating control in practice is gathered because the food to be cooked spills from the outer periphery of the pan, which is the object to be heated, and spreads along the pan, which is the object to be heated. In order to detect the amount of spillage, there is a problem that a detection electrode having a certain length is required.

On the other hand, an electrode 603 having a simple length as shown in FIG. 6 is used, and FIGS.
When the heating coil 602 induction heating is performed in the state where the object to be heated 601 is overlapped and placed on the electrode 603 as shown in FIG. 6 (c), high-frequency power is used. Under the influence of the electric field generated by the induction heating, the electrostatic capacity composed of the electrode and the object to be heated is reduced (FIGS. 6 (d)-(2)). Since a phenomenon (FIG. 6 (d)-(3)) in which the capacity change cannot be observed occurs, there is a problem that a device that does not depend on the mounting state is required.

  The present invention solves the above-described conventional problems, and has a function of detecting practically effective spillage by eliminating the influence of induction heating by forming a plurality of arc-shaped electrodes for detection of spillage. Another object is to provide an induction heating cooker.

In order to solve the conventional problem, an induction heating cooker according to the present invention includes a top plate for placing an object to be heated such as a pan for putting an object to be cooked, and heating for heating the object to be heated. A coil, high-frequency power supply means for supplying high-frequency power for induction heating by the heating coil, a plurality of arc-shaped electrodes with different radii arranged under the top plate, and capacitance of the electrodes are detected Based on an instruction of the overflow detection means, a detection of the overflow detection of the food to be cooked by detecting a change in capacitance by the capacitance detection means, and a detection of the overflow detection means the and control means for controlling the high frequency power supply of the high-frequency power supply means, said plurality of arc-shaped electrodes, the two electrodes adjacent arcs at the end points of each electrode By being connected in a substantially perpendicular electrodes tangentially, characterized in that it is connected to one, the electrode corresponding to the influence of interference to the electrostatic capacitance by the induction heating and difference in size of the object to be heated A plurality of arc-shaped electrodes are used, and the spill detector detects the spilled object in the capacitance formed by the electrode and the heated object, and enters the gap between the electrode and the heated object as a dielectric. By functioning so as to detect the capacitance change generated by functioning and adjusting the amount of heating when the spill occurs, an induction heating cooker having a highly practical spill detection function can be provided.

  The induction heating cooker according to the present invention can provide an induction heating cooker having a practically useful overflow detection function.

The block diagram which shows the structure of the induction heating cooking appliance in Embodiment 1 of this invention. The figure explaining the electrode shape in Embodiment 1 of this invention The flowchart which shows the overflow detection operation | movement in Embodiment 1 of this invention. The figure which shows the mode of the electrostatic capacitance detection value change in Embodiment 1 of this invention. The figure explaining the electrode shape in Embodiment 2 of this invention The figure explaining the subject in a prior art example The figure explaining the state of the top plate in Embodiment 3 of this invention The block diagram which shows the structure of the induction heating cooking appliance in Embodiment 4 of this invention. The figure explaining the intersection confirmation operation in Embodiment 4 of this invention

1st invention is a to-be-cooked object, to-be-heated objects, such as a pot which puts the to-be-cooked object, a top plate for mounting the to-be-heated object, and a heating coil for heating the to-be-heated object High-frequency power supply means for supplying high-frequency power for induction heating by the heating coil, a plurality of electrodes arranged under the top plate, and capacitance detection means for detecting the capacitance of the electrodes , Spilling detection means for detecting spillage of the cooking object, and control means for controlling the heating operation, the electrode is affected by the difference in the size of the heating object and the influence of interference on the capacitance due to induction heating A plurality of fan-shapes are provided to cope with the spilling detection means, and the cooking object spilled in the capacitance formed by the electrode and the heated object enters between the electrode and the heated object, and the dielectric The induction heating cooker is characterized in that the control means adjusts the amount of heat when the spill occurs, based on an instruction from the spill detection means. Thus, it is possible to provide an induction heating cooker equipped with a practically effective bubble spill detection function corresponding to the difference in the size of the object to be heated and the influence of interference on the capacitance due to induction heating.

In addition, the present invention is an induction heating cooker having a structure in which a plurality of sectors having different radii are connected to each other, so that the size of the object to be heated and the influence of interference on capacitance due to induction heating are reduced. on corresponding, it is possible to provide an induction heating cooker capable of ensuring a wide detection area without increasing the detection circuit used in the electrostatic capacitance detection means.

Furthermore, the present invention provides an induction heating cooker capable of suppressing the influence of an electric field generated by induction heating, by connecting a plurality of fan-shaped electrodes to be substantially perpendicular to the tangent line of the sector arc. it can.

2nd invention can make it difficult to receive the influence of the electric field which generate | occur | produces when the said heating coil performs induction heating by setting it as the induction heating cooking appliance which has arrange | positioned the electrode outside the outer periphery of a heating coil. An induction heating cooker can be provided.

A third aspect of the invention is an induction heating cooker in which the outer periphery of the heating coil is substantially circular, and the fan-shaped arc of the electrode is arranged along the direction of an electric field generated when induction heating is performed by the heating coil. By doing so, it is possible to provide an induction heating cooker that can detect the overflowing by eliminating the influence of the electric field generated when the heating coil performs induction heating.

  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 cooker according to the first embodiment of the present invention.

  In FIG. 1, 101 is an object to be cooked, 102 is an object to be heated, 103 is a top plate, 104 is a heating coil, 105 is a high-frequency power supply means, 106 is an electrode, 107 is a capacitance detection means, 108 is a spill detection means. 109 are control means.

  FIG. 2 is a diagram for explaining the electrode shape in the first embodiment, and is a configuration related to the shape of the plurality of arc-shaped electrodes 106 to cope with the difference in diameter of the heated object 102 such as a pan. Indicates the relationship of elements.

  Note that the object to be heated 102 is a pan, the top plate 103 is crystallized glass, the high-frequency power supply means 105 is an inverter, the electrode 106 is a conductor formed by coating or bonding on the lower surface of the top plate 103, electrostatic This configuration can be easily realized by using a circuit for converting the capacitance presented by the electrode 106 into a voltage for the capacitance detection means 107 and a microcomputer for the overflow detection means 108 and the control means 109.

Here, the electrode 106 formed on the lower surface of the top plate 103 exhibits a capacitance using air as a dielectric even when there is nothing on the top plate 103. When the object to be heated 102 is placed here, or the object to be cooked 101 is spilled and enters between the electrodes 106 with the object to be heated 102, the capacitance exhibited by the electrode 106 changes. The electrostatic capacitance detection means 107 provides the electrostatic capacitance detection value to the spillage detection means 108 by sequentially voltage-converting the electrostatic capacitance obtained here.

  The electrode 106 is formed in a shape thinner than the skin depth determined from the operating frequency when the induction heating cooker performs induction heating. By configuring the electrode 106 to be thinner than the skin depth, generation of eddy current inside the electrode 106 due to the influence of the magnetic field generated when the object to be heated 102 is inductively heated can be suppressed, and detection of capacitance change due to spilling can be prevented. Unnecessary electric field generation can be suppressed.

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

  FIG. 3 is a flowchart showing the overflow detection operation in the first embodiment of the present invention.

  First, when the user puts the object to be cooked 101 into the object to be heated 102 and instructs to start heating, the control means 109 operates the high frequency power supply means 105 to input high frequency power to the object to be heated 102 (step 301). Here, the overflow detection means 108 detects the electrostatic capacitance of the electrode 106 by the electrostatic capacity detection means 107, and substitutes the electrostatic capacitance detection value at the start of heating into the variable for the detection of the overflow (previous detection value) ( Step 302). Thereafter, the elapse of a predetermined time (for example, 0.5 seconds) is confirmed (step 303), and the overflow detection process is executed (after step 304).

  The overflow detection means 108 detects the electrostatic capacitance of the electrode 106 by the electrostatic capacitance detection means 107, and substitutes the detected value for the current detection value (step 304). Here, the overflow detection means 108 compares the difference between the (previous detection value) and the (current detection value) of the capacitance of the electrode 106 with a predetermined value (for example, 1/10 of the maximum voltage change amount) to determine whether there is any overflow. Judgment is made (step 305), and when the spillover detection is not recognized, the spillover detection process is terminated and the process returns to a predetermined time. When the spillover detection is detected, the current heating amount is adjusted to the heating amount adjustment power (stop) Or the temperature maintenance power of about 500 W), the user is notified that the spill has occurred, and the spill detection operation is terminated.

  In this detection operation, the capacitance change is generated by the mechanism described below. This is a change that occurs because the capacitance is proportional to the area constituting the capacitance and the dielectric constant between the conductors constituting the capacitance, and inversely proportional to the distance between the conductors constituting the capacitance.

In the case of a pan having a small diameter so that the object to be heated 102 does not cover the electrode 106, the capacitance change only slightly increases if the spilled object 101 is simply placed on the electrode 106. In order to observe a practical increase in capacitance, it is necessary for the spilled 301 to enter as a dielectric in the capacitance formed by the object to be heated 102 and the electrode 106 as shown in FIG. . On the other hand, if the electrode 106 is arranged on the heating coil 104 to make it easier to detect the spilling of a pot with a small diameter, the capacitance decreases due to the influence of the electric field generated during induction heating (on the capacitor). It is necessary that the electrode 106 not be disposed on the heating coil 104, as if a high-frequency electric field is applied, the high-frequency current flows and discharges electricity. Further, when the electrode 106 is arranged in the diameter direction of the circular heating coil 104 (FIGS. 6A to 6C), the influence of the electric field on the electrode 106 is stronger as it is closer to the heating coil 104 and weaker as it is farther away. As a result, the capacitance during induction heating decreases, and the increase in capacitance cannot be observed. Therefore, the electrode 106 needs to be configured so that the electric fields generated by induction heating are equivalent. When the heating coil 104 is circular, the generated combined electric field is concentric, so that it is necessary to configure it in an arc shape so as not to be affected by the electric field generated when induction heating is performed. .

  By configuring the electrode 106 in an arc shape in this manner, the influence of the electric field is eliminated, the area for increasing the capacitance is increased, and further, spillage that does not know where to spill from the heated object 102 is widened. Can be covered.

  In the case of a pan having a diameter in which the object to be heated 102 overlaps with the electrode 106, the electrostatic capacitance is obtained at the place where the spilled 301 enters the space between the object to be heated 102 and the electrode 106 among the plurality of electrodes 106. Can be detected (FIGS. 4B and 4C).

  As described above, in the present embodiment, the electrode 106 has a plurality of arc shapes for dealing with the influence of the difference in the size of the object 102 to be heated and the influence of interference on the capacitance due to induction heating, so that the overflow detection is performed. Capacitance change that occurs when the object to be cooked 101 is inserted between the electrode 106 and the object to be heated 102 and functions as a dielectric is detected in the capacitance formed by the electrode 106 and the object to be heated 102. By adjusting the amount of heating when a spill occurs, a highly practical spill detection function can be provided.

  Further, by disposing the electrode 106 in the vicinity of the outer edge of the outer periphery of the heating coil 104, it is possible to detect the spillage while eliminating the influence of the electric field generated when the heating coil performs induction heating.

  Further, the outer periphery of the heating coil 104 is substantially circular, and the electrode 106 is arranged along the direction of the electric field generated when the induction heating is performed by the heating coil 104. It is possible to detect the spillage without the influence of the electric field.

(Embodiment 2)
FIG. 5 is a diagram showing the relationship between the shape of the electrode 106 and the related components in the second embodiment of the present invention. The block diagram of the induction heating cooker is the same as FIG.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In the drawings, the same reference numerals are given to portions showing the same operations as those in the first embodiment.

  The basic operation of the induction heating cooker in the second embodiment is the same as that in the first embodiment. In the second embodiment, as shown in FIG. 5, an arc-shaped electrode that is not easily affected by an electric field when induction heating is performed using a circular heating coil 104 is used as a basic detection configuration, and the arc-shaped structures are arranged as electrodes. Connected with. As a result, a wide detection area can be secured without increasing the number of detection circuits used in the capacitance detection means 107 required for the number of electrodes 106 in the first embodiment.

  Note that an arc-shaped electrode that is not easily affected by an electric field when induction heating is performed using the circular heating coil 104 has a basic detection configuration, and the connection portion of the arc-shaped structure cannot be excluded from the influence of induction heating. Since it is necessary to connect the electrodes as short as possible, it is necessary to connect the electrodes having a plurality of arc-shaped structures with electrodes that are approximately perpendicular to the arc tangent, thereby reducing the distance affected by the electric field. It is preferable to suppress the influence.

  Similarly to the first embodiment, the electrode 106 is formed in a shape thinner than the skin depth determined from the operating frequency when the induction heating cooker performs induction heating.

As described above, in this embodiment, the electrode 106 has a structure in which a plurality of arc-shaped electrodes having different radii are connected to each other, so that the size of the object to be heated 102 and the static due to induction heating are reduced. It is possible to provide an induction heating cooker that can secure a wide detection area without increasing the number of detection circuits used in the capacitance detection means, in response to the influence of interference on the capacitance.

(Embodiment 3)
FIG. 7 is a diagram illustrating a relationship between components related to the top plate 103 according to the third embodiment of the present invention. In FIG. 7, reference numeral 701 denotes an effective range line indicating a detectable range of overflowing. The block diagram of the induction heating cooker is the same as FIG.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In the drawings, the same reference numerals are given to portions showing the same operations as those in the first embodiment.

  The basic operation of the induction heating cooker in the third embodiment is the same as that in the first embodiment. In the third embodiment, as shown in FIG. 7, an effective range line indicating the overflow detection detectable range is set, and as shown in FIG. 7B, the object to be heated is deviated from the effective range line 701. The installation range of the object to be heated 102 is clearly shown so that 102 is not placed. When a plurality of induction heating coils 104 are arranged as shown in FIG. 7 and the object to be heated 102 is placed out of the effective range line, FIG. 6 is used in [Problem to be Solved by the Invention]. As described above, the situation in which the object to be heated 102 is placed so as to overlap the electrode 106 can be clearly shown to the user.

  As described above, in the present embodiment, by specifying the effective range line 701, it is possible to provide an induction heating cooker that clearly indicates to the user the range where the overflow can be detected.

  It goes without saying that the effective range line 701 may indicate the range with light such as an LED for easier understanding.

(Embodiment 4)
FIG. 8 shows a block diagram of an induction heating cooker according to the fourth embodiment of the present invention. In FIG. 8, reference numeral 801 denotes intersection confirmation means. This configuration can be easily realized by using a microcomputer as the intersection confirmation means.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In the drawings, the same reference numerals are given to portions showing the same operations as those in the first embodiment.

  The basic operation of the induction heating cooker in the fourth embodiment is the same as that in the first embodiment. As shown in FIG. 9A, a state in which the object to be heated 102 is placed on the electrode 106 so as to overlap (as described with reference to FIG. 6 in [Problems to be solved by the invention]) When induction heating is performed by the heating coil 104 in FIG. 9B- (1)), the electrostatic capacitance formed by the electrode and the object to be heated is affected by the electric field generated by induction heating using high-frequency power. Decreases (FIG. 9 (b)-(2)), and a phenomenon (FIG. 9 (b)-(3)) in which a change in capacitance cannot be observed even if a spill occurs is generated.

  The crossing confirmation unit 801 indicates that when induction heating is started in a state where the electrode 106 and the object to be heated 102 cross each other, the capacitance detection unit 801 indicates a change as shown in FIGS. It has a function of confirming by monitoring the output of 107.

  When the crossing confirmation unit 801 confirms the intersection between the electrode 106 and the object to be heated 102 and transmits it to the control unit 109, the control unit 109 informs the user that it is impossible to change the placement location of the object to be heated 102 or to detect the overflowing. Inform.

  As described above, in this embodiment, the crossing confirmation for confirming that the output of the capacitance detecting means 107 exhibits the influence of the electric field due to the induction heating when the electrode 106 and the heated object 102 cross each other. By providing the means 801, it is possible to provide an induction heating cooker capable of confirming that the spillover is not detected when the user places the article to be heated 102 in the range where the spillage cannot be detected.

  As described above, the induction heating cooker according to the present invention uses a plurality of fan-shaped shapes for the electrodes to cope with the influence of interference on the capacitance due to the difference in size of the object to be heated and induction heating, The spillage detection means detects a change in capacitance that occurs when the cooking object spilled into the capacitance formed by the electrode and the object to be heated enters between the electrode and the object to be heated and functions as a dielectric. By functioning to detect and adjusting the amount of heating when a spill occurs, an induction heating cooker having a highly practical spill detection function can be provided.

  This operation can also be applied to gas combustion without induction heating or cooking using an electric heater.

DESCRIPTION OF SYMBOLS 101 To-be-cooked object 102 To-be-heated object 103 Top plate 104 Heating coil 105 High frequency electric power supply means 106 Electrode 107 Capacitance detection means 108 Overflow detection means 109 Control means 401 Overflow 701 Effective range display line 801 Crossing confirmation means

Claims (3)

A top plate for placing an object to be heated, such as a pan into which the object is to be cooked, a heating coil for heating the object to be heated, and a high frequency for supplying high frequency power for induction heating by the heating coil A power supply means; a plurality of arc-shaped electrodes with different radii arranged under the top plate; and a capacitance detection means for detecting a capacitance of the electrodes;
Overflow detection means for detecting whether a capacitance change has been detected by the electrostatic capacity detection means to detect whether the cooking object has overflowed;
Control means for controlling the high-frequency power supplied by the high-frequency power supply means based on an instruction from the overflow detection means ;
The plurality of arc-shaped electrodes are induction heating cookers connected to each other by connecting two adjacent electrodes with electrodes substantially perpendicular to the arc tangent line at the end points of the electrodes . The induction heating cooker according to claim 1 , wherein the electrode is disposed outside the outer periphery of the heating coil so as not to be affected by an electric field generated when the heating coil performs induction heating. The outer periphery of the heating coil is substantially circular, and the arcuate structure of the electrode is disposed along the direction of an electric field generated when induction heating is performed by the heating coil. Or the induction heating cooking appliance of 2.

Images