JP5874033B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker, and more particularly, to an induction heating cooker that can avoid erroneous detection of a spillage detection function due to a capacitance change that may occur during normal cooking.

  Conventionally, this type of induction heating cooker determines that “spilling has occurred” when the capacitance of the electrode provided under the top plate increases above a predetermined value, and causes a high-frequency current to flow through the induction heating coil. Is limited or stopped (see, for example, Patent Document 1).

JP 2008-159494 A

  However, in the above-described conventional configuration, in all cases where the capacitance increases beyond a predetermined value in a single electrode, the spillage is determined. Therefore, even in the increase in capacitance due to pan deviation that may occur during cooking. The inverter is stopped or the current supplied to the induction heating coil is limited, and the user may not be able to continue cooking.

  Capacitance fluctuations that can occur during normal cooking, for example, when a cloth is touched, touched by hand, or when a metal candy touches the top plate, etc. However, the high-frequency current flowing through the induction heating coil is limited or stopped, and the user may not be able to continue cooking even during normal cooking.

  The object of the present invention is to solve the above-mentioned problems and avoid erroneous detection of spillage without stopping the circuit or reducing the high-frequency current due to the capacitance fluctuation that may occur due to pan deviation during cooking. It is to provide an induction heating cooker.

In order to solve the conventional problem, the induction heating cooker according to the present invention is:
A top plate to install the pan,
An induction heating coil provided under the top plate for heating the pan;
A first electrode and a second electrode are provided at a lower portion of the top plate, are made of a conductor disposed in the vicinity of the outer periphery of the induction heating coil, and are disposed in different directions as viewed from the center of the induction heating coil. Electrodes,
An inverter for supplying a high-frequency current to the induction heating coil;
A first capacitance detector that detects a change in capacitance of the first electrode;
A second capacitance detector that detects a change in capacitance of the second electrode;
A spillage determination unit that determines that spillage has occurred when the capacitance detected by the first capacitance detection unit increases by a first predetermined value or more;
When the spillage determination unit determines that the spillage has occurred, the heating operation of the inverter is stopped or the current flowing to the induction heating coil is limited, and the spillage determination unit does not determine that the spillage has occurred. A controller that continues the heating operation without limiting the current flowing through the induction heating coil,
The overflow determination unit is configured to detect the electrostatic capacitance detected by the first electrostatic capacitance detection unit even when the electrostatic capacitance detected by the first electrostatic capacitance detection unit increases by more than the first predetermined value. When the capacitance detected by the second capacitance detection unit is decreased by a second predetermined value or more simultaneously with the increase of the capacitance, it is not determined that a spill has occurred.

  This eliminates false detection of spillage due to changes in the capacitance of the electrode when the pan is moved, and improves the accuracy of detection of spillage, compared to the case where it is detected and determined that spillage has occurred by the conventional method. It is possible to provide the intended induction heating cooker.

  According to the induction heating cooker according to the present invention, the combination of the change of a plurality of electrodes, the change in the capacitance of the electrode when the pan is displaced and the change in the capacitance due to the spill are discriminated, and the spillage is accurately detected. By performing detection, the above-described conventional problems are solved, and by measuring the capacitance fluctuation, it is possible to eliminate malfunction of detection of spilling and continue cooking.

It is a block diagram which shows the structure of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a top view showing the position of the induction heating coil of the induction heating cooking appliance of FIG. 1A, a pan, and an electrode. It is a block diagram which shows the structure of the induction heating cooking appliance which concerns on Embodiment 2 of this invention. It is a top view showing the position of the induction heating coil of the induction heating cooking appliance of FIG. 2, a pan, and an electrode. It is a graph which shows the electrostatic capacitance increase by the spilling of the induction heating cooking appliance of FIG. It is a graph which shows the change of an electrostatic capacitance when the pan of the induction heating cooking appliance of FIG. 2 slip | deviated. It is a top view showing the position of the induction heating coil at the time of pan deviation of the induction heating cooking appliance of FIG. 2, a pan, and an electrode.

The first invention is a top plate on which a pan is installed;
An induction heating coil provided under the top plate for heating the pan;
A first electrode and a second electrode are provided at a lower portion of the top plate, are made of a conductor disposed in the vicinity of the outer periphery of the induction heating coil, and are disposed in different directions as viewed from the center of the induction heating coil. Electrodes,
An inverter for supplying a high-frequency current to the induction heating coil;
A first capacitance detector that detects a change in capacitance of the first electrode;
A second capacitance detector that detects a change in capacitance of the second electrode;
A first spillage determination unit that determines that spillage has occurred when the capacitance detected by the first capacitance detection unit increases by a first predetermined value or more;
When the spillage determination unit determines that the spillage has occurred, the heating operation of the inverter is stopped or the current flowing to the induction heating coil is limited, and the spillage determination unit does not determine that the spillage has occurred. A controller that continues the heating operation without limiting the current flowing through the induction heating coil,
The overflow determination unit is configured to detect the electrostatic capacitance detected by the first electrostatic capacitance detection unit even when the electrostatic capacitance detected by the first electrostatic capacitance detection unit increases by more than the first predetermined value. When the capacitance detected by the second capacitance detection unit is decreased by a second predetermined value or more simultaneously with the increase of the capacitance, it is not determined that a spill has occurred.

  In this configuration, since the first electrode and the second electrode are disposed in the vicinity of the induction heating coil, the capacitance increases as moisture spilled from the pan approaches. Therefore, when the capacitance of the first electrode detected by the first capacitance detection unit increases, the spillage determination unit determines spillage.

  However, when there is no spilling from the pan, even if the pan on the top plate is displaced so as to approach the first electrode for some reason, the static detected by the first capacitance detector is detected. The capacity increases and the occurrence of spillage is detected by mistake.

  At this time, if the pan is moving away from the second electrode, the capacitance of the second electrode detected by the second capacitance detector is lowered.

  When the drop detection unit detects a decrease in the capacitance of the second electrode, it does not detect the occurrence of a spill even when the capacitance of the first electrode increases, and the control unit flows to the induction heating coil. Continue heating without limiting the current.

  With this configuration, compared to the conventional case where the occurrence of spillage is detected, a change in the capacitance of the electrode when the pan is moved closer to the first electrode is erroneously determined to have been spilled. It is possible to provide an induction heating cooker that eliminates detection and improves detection accuracy of spillage.

  In particular, the second invention determines that a spill has occurred when the capacitance detected by the second capacitance detector increases by a third predetermined value or more, and Even when the capacitance detected by the second capacitance detection unit increases by the third predetermined value or more, the first capacitance is detected simultaneously with the increase of the capacitance detected by the second capacitance detection unit. In the case where the capacitance detected by the first capacitance detection unit decreases by a fourth predetermined value or more, it is not determined that a spill has occurred.

  With this configuration, it is possible to identify the spilling in the direction of the second electrode and the pan shift in the direction of the second electrode, so that the detection range can be expanded and the accuracy of the spilling determination function can be increased.

  In the third invention, in particular, the first electrode and the second electrode of the first invention are each formed in a strip shape and arranged at a substantially constant distance from the outer peripheral portion of the induction heating coil. Features.

  As a result, the distance between each electrode and the induction heating coil can be made constant, and when moisture is spilled from the pan, the occurrence of spillage is detected accurately, and the pan placed on the induction heating coil is moved in any direction. Even if it is shifted, erroneous detection of spillage can be prevented with a certain accuracy, and an easy-to-use induction heating cooker can be provided.

The fourth invention is particularly the induction heating cooker of the first or second invention,
The conductor is provided in the lower part of the top plate and is arranged near the outer periphery of the induction heating coil, and is arranged in different directions as viewed from the center of the first and second electrodes and the induction heating coil. A third electrode to be
The spillover determination unit determines that spillage has occurred when the capacitance detected by the third capacitance detection unit increases by a fifth predetermined value or more, and the third capacitance detection unit Even when the capacitance detected in step S3 increases by more than the fifth constant value, the first capacitance detection unit is simultaneously with the increase in capacitance detected by the third capacitance detection unit. When the capacitance detected in step 4 decreases by more than the fourth constant value or when the capacitance detected by the second capacitance detection unit decreases by more than the second predetermined value, It is characterized by not determining that this has occurred.

  This makes it possible to discriminate between a pan shift shifted in the direction of the third electrode and a spill in the direction of the third electrode, as compared with the case of detection with two electrodes, and the spilling in a wide direction with high accuracy. It is possible to provide an easy-to-use induction heating cooker having a more stable cooking performance and safety function.

  In a fifth aspect of the invention, in particular, in the induction heating cooker of the fourth aspect of the invention, the capacitance detected by the first capacitance detector increases more than the first predetermined value, and the second Even when the capacitance detected by the capacitance detection unit of the first capacitance does not decrease by more than the second constant value, the third capacitance is increased simultaneously with the increase of the capacitance detected by the first capacitance detection unit. When the capacitance detected by the capacitance detection unit decreases by a sixth constant value or more, it is not determined that a spill has occurred.

  As a result, compared with the case of detecting with two electrodes, it is possible to identify a pan shift shifted in the direction of the first electrode, the second electrode, and the third electrode, and the overflow in that direction. It is possible to provide an easy-to-use induction heating cooker having a stable cooking performance and a safe function.

  In the sixth and seventh inventions, in particular, the first electrode, the second electrode, and the third electrode in the fourth invention and the fifth invention are each formed in a strip shape, and from the outer periphery of the induction heating coil. It is characterized by being arranged at a substantially constant distance.

  As a result, the distance between each electrode and the induction heating coil can be made constant, and when moisture is spilled from the pan, the occurrence of spillage is detected accurately, and the pan placed on the induction heating coil is moved in any direction. Even if it is shifted, erroneous detection of spillage can be prevented with a certain accuracy, and an easy-to-use induction heating cooker 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. In the drawings, the same or similar components are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1A is a block diagram showing the configuration of the induction heating cooker according to the first embodiment of the present invention.

  In FIG. 1A, the induction heating cooker which concerns on this Embodiment is provided under the top plate 2 which installs the pan 1, the induction heating coil 3 which heats the pan 1, and the top plate 2 A first electrode 4 and a second electrode 5 which are provided in a lower portion and are made of a conductor disposed in the vicinity of the outer periphery of the induction heating coil 3 and are disposed in different directions as viewed from the center O of the induction heating coil 3. An inverter 10 that supplies a high-frequency current to the induction heating coil 3, a first capacitance detector 6 that determines a change in capacitance of the first electrode 4, and a capacitance of the second electrode 5. When the capacitance detected by the second capacitance detection unit 7 that detects the change of the first capacitance and the first capacitance detection unit 6 increases by a first predetermined value or more, it is determined that the spill has occurred. The spillage judgment unit 8 and spillage occurred When the spillage determination unit 8 determines, the heating operation of the inverter 10 is stopped or the current flowing through the induction heating coil 3 is limited, and if the spillage determination unit 8 does not determine that the spillage has occurred, the induction heating coil 3 A control unit 9 that continues the heating operation without limiting the flowing current, and the spillage determination unit 8 has the capacitance detected by the first capacitance detection unit 6 increased by a first constant value or more. However, when the capacitance detected by the second capacitance detection unit 7 decreases at the same time as the increase in capacitance detected by the first capacitance detection unit 6, The spillage determination unit 8 does not determine that spillage has occurred.

  The spillage determination unit 8 determines that spillage has occurred when the capacitance detected by the second capacitance detection unit 7 has increased by a third predetermined value or more, and detects the second capacitance detection. Even when the capacitance detected by the unit 7 increases by a third constant value or more, the first capacitance detection unit 6 simultaneously with the increase of the capacitance detected by the second capacitance detection unit 7. If the electrostatic capacitance detected at step 4 falls below a fourth constant value, it is not determined that a spill has occurred.

  FIG. 1B is a plan view of the positional relationship among the induction heating coil 3, the pan 1, and each electrode in FIG. 1A as viewed from above. As shown in FIG. 1B, the first electrode 4 and the second electrode 5 are each formed in a strip shape so as to face each other, and are arranged at a substantially constant distance from the outer peripheral portion of the induction heating coil 3. Has been. In this case, since the induction heating coil 3 is formed in a disc shape, the first and second coils are formed around the outer peripheral portion of the induction heating coil 3 so as to form a circular shape concentric with the outer peripheral portion as a whole. The electrodes 4 and 5 are arranged.

  The operation and action of the induction cooking device configured as described above will be described below.

  In FIG. 1A, the inverter 10 induction-heats the pan 1 by supplying a high-frequency current to the induction heating coil 3. At this time, the operation in the case where moisture falls from the pan 1 onto the top plate 2 will be described. Since the 1st electrode 4 and the 2nd electrode 5 are arrange | positioned in the outer vicinity of the outer peripheral part of the induction heating coil 3, an electrostatic capacitance increases with the water spilled from the pan 1. FIG.

  When spilling from the pan 1 has started, the spilled water has not yet reached the top plate 2, so that the capacitances of the first and second electrodes do not change.

  Thereafter, the spilled water reaches the top plate 2 through the side surface of the pan 1 or the like, and reaches the upper portion of the first electrode 4 disposed in the vicinity of the outer periphery of the induction heating coil 3. Since the moisture does not reach the two electrodes at the same time, and there is often a slight time difference, when the moisture reaches the upper part of the first electrode 4, the first electrode 4 and the pan 1 or the first electrode 4 and the induction heating coil 3 are coupled with a capacitor (capacitance) via moisture.

  For this reason, the electrostatic capacitance of the 1st electrode 4 will increase. The first capacitance detection unit 6 detects a change in the capacitance of the first electrode 4 and uses the capacitance before the capacitance of the first electrode 4 changes as a reference value. When the capacitance increases from the reference value by a first constant value, the spillage determination unit 8 determines that spillage has occurred.

  At this time, since the moisture has not yet reached the upper part of the second electrode 5, the capacitance of the second electrode 5 does not change greatly. Since the capacitance of the first electrode 4 increases and the capacitance of the second electrode 5 does not change, that is, the change that decreases by more than the second constant value is not measured. It is determined that the spilling from the pan 1 is not a false detection, and information indicating the occurrence of the spilling is sent to the control unit 9, and the control unit 9 stops the heating operation of the inverter 10 or the induction Spilling can be stopped by limiting the current flowing through the heating coil 3.

  Next, when the pan 1 is heated, for some reason, for example, when the user moves the pan 1 with the pan 1, the center of the pan 1 deviates from the center O of the induction heating coil 3. The operation will be described. First, suppose that the center of the pan 1 is heated in accordance with the center O of the induction heating coil 3. From here, the center of the pot 1 under cooking will shift | deviate from the center O of the induction heating coil 3, and the change of the electrostatic capacitance of an electrode when the pan 1 moves to the direction of the 1st electrode 4 is demonstrated.

  When the center of the pan 1 is placed on the center O of the induction heating coil 3 and heating is performed without spilling, the capacitances of the first and second electrodes 4 and 5 hardly change. Thereafter, when the center of the pan 1 is shifted from the center O of the induction heating coil 3 in the direction of the first electrode 4 for some reason, the capacitance of the first electrode 4 is the same as that of the pan 1 and the first electrode 4. Increase to get closer.

  At the same time, the capacitance of the second electrode 5 decreases because the pan 1 is separated from the second electrode 5. As described above, when the capacitance of the first electrode 4 is increased, the overflow determination unit 8 is configured to reduce the capacitance of the second electrode 5 by a second predetermined value or more from the value before the change. In addition, it is determined that the pan 1 has shifted, and an operation is not performed in which it is not determined that “swelling has occurred”.

  Conversely, even when the pan 1 is displaced in the direction of the second electrode 5, the spillage determination unit 8 has a capacitance detected by the second capacitance detection unit 7 equal to or greater than a third constant value. Even if it is determined that the spilling has occurred when the capacitance increases, and the capacitance detected by the second capacitance detection unit 7 increases by a third predetermined value or more, the second capacitance detection unit 7 When the capacitance detected by the first capacitance detection unit 6 decreases at the same time as the increase in the detected capacitance, it is not determined that a spill has occurred. A determination operation similar to that in the case where the second electrode 5 is displaced in the direction is performed. The first constant value and the third constant value may be the same value or different values. Further, the second constant value and the fourth constant value may be the same value or different values.

  As described above, according to the invention of the present embodiment, even when an increase in capacitance is confirmed for each of the first electrode 4 and the second electrode 5, it is caused by spilling. It can be determined whether there is a decrease in a predetermined capacitance of each of the other electrodes (which may be set for each electrode). Therefore, the user cooks without causing an inconvenient state for the user that the inverter 10 stops the heating operation or limits the current flowing through the induction heating coil 3 even though no spilling has occurred. Can continue. These operations reduce the chances of false detection of the spillover detection function and improve the accuracy of spillover detection, making it more stable than when detecting and detecting the occurrence of spillage using the conventional method. It is possible to provide an easy-to-use cooking device equipped with cooking performance and safety features.

  Further, by detecting both the increase in the capacitance of the first electrode 4 and the increase in the capacitance of the second electrode 5 and determining that the spill has occurred as described above, the induction heating coil The presence or absence of spillage can be determined in a wider range from the center of 3.

(Embodiment 2)
FIG. 2 is a block diagram showing the configuration of the induction heating cooker according to the second embodiment of the present invention.

  In FIG. 2, the induction heating cooker according to the present embodiment is made of a conductor that is provided in the lower part of the top plate 2 in the vicinity of the outer periphery of the induction heating coil 3 in addition to the configuration of the first embodiment. The capacitances of the third electrode 11 and the third electrode 11 arranged in different directions when viewed from the center O (see FIG. 3) of the first electrode 4 and the second electrode 5 and the induction heating coil 3. A third capacitance detection unit 12 that detects a change, and the overflow determination unit 8 has a capacitance detected by the third capacitance detection unit 12 increased by a fifth predetermined value or more. Even if it is determined that a spill has occurred and the capacitance detected by the third capacitance detection unit 12 has increased by a fifth fixed value or more, the third capacitance detection unit 12 detects it. The electrostatic capacity detected by the first electrostatic capacity detection unit 6 simultaneously with the increase of the electrostatic capacity As a configuration in which it is not determined that a spill has occurred when the amount decreases by a fourth constant value or more, or when the capacitance detected by the second capacitance detection unit 7 decreases by a second constant value or more. Yes.

In addition, the capacitance detected by the first capacitance detector 6 increases by a first constant value or more, and the capacitance detected by the second capacitance detector 7 is a second constant. Even if the value does not decrease more than the value, the capacitance detected by the third capacitance detection unit 12 at the same time as the increase in capacitance detected by the first capacitance detection unit 6 exceeds the sixth constant value. When it falls, it is set as the structure which does not determine that the spill has occurred.

  FIG. 3 is a plan view of the positional relationship among the induction heating coil 3, the pan 1, and each electrode of FIG. As shown in FIG. 3, the first electrode 4, the second electrode 5, and the third electrode 11 are each formed in a strip shape, and are arranged at a substantially constant distance from the outer periphery of the induction heating coil 3. Has been. In this case, since the induction heating coil 3 is formed in a disc shape, the first, second and second portions are formed around the outer peripheral portion of the induction heating coil 3 so as to form a circular shape concentric with the outer peripheral portion as a whole. Third electrodes 4, 5, 11 are arranged.

  The operation and action of the induction heating cooker configured as described above will be described below.

  In this configuration, the inverter 10 supplies the high frequency current to the induction heating coil 3 to inductively heat the pan 1. At this time, an operation in the case where moisture falls from the pan 1 onto the top plate 2 will be described. Since the first electrode 4, the second electrode 5, and the third electrode 11 are arranged near the outside of the outer periphery of the induction heating coil 3, the capacitance increases due to the water spilled from the pan 1.

  This change will be described with reference to FIGS. 4A and 4B. 4A is a graph showing an increase in capacitance due to spilling of the induction heating cooker of FIG. 2, and FIG. 4B is a graph showing a change in capacitance when the pan 1 of the induction heating cooker of FIG. 2 is displaced. is there.

  In FIG. 4A, let Ta be the time when the spill from the pan 1 started. At this time, since the spilled water has not yet reached the top plate 2, the capacitance of the first, second and third electrodes 4, 5, 11 has not changed.

  Thereafter, the spilled water reaches the top plate 2 by traveling along the side surface of the pan 1 and reaches the upper portion of the first electrode 4 disposed in the vicinity of the outer periphery of the induction heating coil 3. It is assumed that the moisture reaches the upper part of the first electrode 4 this time because the moisture does not reach the three electrodes 4, 5, and 11 at the same time, and there is often a slight time difference.

  When moisture reaches the upper portion of the first electrode 4, the first electrode 4 and the pan 1 or the first electrode 4 and the induction heating coil 3 are capacitively coupled via moisture. For this reason, the electrostatic capacitance of the 1st electrode 4 will increase. The first capacitance detection unit 6 detects a change in the capacitance of the first electrode 4 and uses the capacitance before the capacitance of the first electrode 4 changes as a reference value. The spillage determination unit 8 determines that spillage has occurred when the capacitance increases by a first constant value (ΔC1) from the reference value.

  This time is Tb in FIG. 4A. At this time, since the moisture has not yet reached the upper portions of the second electrode 5 and the third electrode 11, the capacitances of the second electrode 5 and the third electrode 11 do not change greatly. Since the electrostatic capacitance of the first electrode 4 increases by more than the first predetermined value and the electrostatic capacitance of the second electrode 5 and the third electrode 11 does not change, The change of the capacitance of the electrode 5 lower than the second predetermined value is not measured, and the change of the capacitance of the third electrode 11 lower than the sixth constant value is not measured. It is determined that the spilling from 1 is not a false detection, and the control unit 9 sends “information determined that the spilling has occurred” to the control unit 9, and the control unit 9 stops the heating operation of the inverter 10 or the induction Spilling can be stopped by limiting the current flowing through the heating coil 3.

  Next, when the pan 1 is heated, for some reason, for example, when the user moves the pan 1 with the pan 1, the center of the pan 1 deviates from the center O of the induction heating coil 3. The operation will be described. FIG. 3 is a plan view showing the positions of the induction heating coil 3, the pan 1, and the electrodes 4, 5, and 11 of the induction heating cooker of FIG. 2, and FIG. 5 shows the induction heating cooker of FIG. It is a top view showing the position of the induction heating coil 3, the pan 1, and the electrodes 4, 5, and 11.

  First, as shown in FIG. 3, it is assumed that the center of the bottom surface of the pan 1 is heated in accordance with the center O of the induction heating coil 3. With reference to FIG. 4B, the change in the capacitance of the electrodes 4, 5, 11 when the pan 1 during cooking is shifted from here and the pan 1 moves in the direction of the second electrode 5 as shown in FIG. 5 will be described. To do.

  In FIG. 3, when the center of the pot 1 is placed on the center O of the induction heating coil 3 and heating is performed without spilling, the first, second, and third electrodes 4, 5, and 11 There is almost no change in capacitance. After that, when the center of the pan 1 is shifted from the center O of the induction heating coil 3 in the direction of the third electrode 11 for some reason from time Tc, the capacitance of the third electrode 11 is the same as that of the pan 1 and the second electrode 11. Increased as the electrodes approach. At the same time, the capacitances of the first electrode 4 and the second electrode 5 decrease because the pan 1 is separated from the first and second electrodes 4 and 5.

As described above, even when the capacitance of the electrode 11 increases by the fifth constant value (ΔC1), the capacitance of the electrode 4 decreases by the fourth constant value (ΔC2) or more, or When the electrostatic capacity decreases by a second constant value (ΔC2) or more, it is not determined that “spilling has occurred”.
In addition, the capacitance detected by the first capacitance detector 6 increases by a first constant value or more, and the capacitance detected by the second capacitance detector 7 is a second constant. Even if the value does not decrease more than the value, the capacitance detected by the third capacitance detection unit 12 at the same time as the increase in capacitance detected by the first capacitance detection unit 6 exceeds the sixth constant value. If it falls, it may not be determined that a spill has occurred. The overflow determination unit 8 determines that the pan 1 has shifted when at least one of the capacitances of the electrodes 4, 5 and 11 has decreased by a certain amount (ΔC2) from before the change, and the capacitances of the other electrodes If an operation that does not determine that “spilling has occurred” is performed even if the value increases by a predetermined value or more for each electrode, it is possible to determine the overflowing more accurately.

  The fifth constant value may be the same value or a different value from the first constant value or the third constant value. Further, the sixth constant value may be the same value or a different value from the second constant value or the fourth constant value.

  As shown in FIG. 4B, the increase in the capacitance of the first electrode 4 becomes −ΔC2 at the timing of time Td due to the pan shift starting from time Tc, and the spillage determination unit 8 does not spill from the pan 1. Therefore, the spillage determination unit 8 does not send “information on the occurrence of spillage” to the control unit 9. Therefore, the user can continue cooking without unintentionally stopping the heating operation or limiting the current flowing through the induction heating coil 3.

  With these operations, it is possible to eliminate false detection of spillage and improve the accuracy of detection of spillage, compared to the case where the occurrence of spillage is detected and detected by the conventional method. It is possible to provide an easy-to-use cooking device.

  As described above, according to the induction heating cooker according to the present invention, the combination of changes in a plurality of electrodes can be used to determine whether the pan is displaced or to spill, and to accurately detect the spill. Since it is possible to avoid erroneous detection of spilling without stopping the circuit or reducing the high-frequency current due to the capacitance fluctuation that can occur during normal cooking, it is effective for use as a cooking appliance.

1 ... pot,
2 ... Top plate,
3 ... induction heating coil,
4 ... 1st electrode,
5 ... second electrode,
6 ... 1st electrostatic capacitance detection part,
7: Second capacitance detection unit,
8 ... Spillover judging unit,
9: Control unit,
10: Inverter,
11 ... second electrode,
12 ... Third capacitance detection unit.

Claims (7)

A top plate to install the pan,
An induction heating coil provided under the top plate for heating the pan;
A first electrode and a second electrode are provided at a lower portion of the top plate, are made of a conductor disposed in the vicinity of the outer periphery of the induction heating coil, and are disposed in different directions as viewed from the center of the induction heating coil. Electrodes,
An inverter for supplying a high-frequency current to the induction heating coil;
A first capacitance detector that detects a change in capacitance of the first electrode;
A second capacitance detector that detects a change in capacitance of the second electrode;
A spillage determination unit that determines that spillage has occurred when the capacitance detected by the first capacitance detection unit increases by a first predetermined value or more;
When the spillage determination unit determines that the spillage has occurred, the heating operation of the inverter is stopped or the current flowing to the induction heating coil is limited, and the spillage determination unit does not determine that the spillage has occurred. A controller that continues the heating operation without limiting the current flowing through the induction heating coil,
The overflow determination unit is configured to detect the electrostatic capacitance detected by the first electrostatic capacitance detection unit even when the electrostatic capacitance detected by the first electrostatic capacitance detection unit increases by more than the first predetermined value. An induction heating cooker characterized in that when the capacitance detected by the second capacitance detection unit decreases at the same time as the increase in capacitance, a drop in boiling is not determined.   The spillage determination unit determines that spillage has occurred when the capacitance detected by the second capacitance detection unit increases by a third predetermined value or more, and the second capacitance detection unit Even when the capacitance detected at the third constant value or more increases, the first capacitance detection unit simultaneously increases the capacitance detected by the second capacitance detection unit. The induction heating cooker according to claim 1, wherein when the detected capacitance is decreased by a fourth constant value or more, it is not determined that boiling over has occurred.   2. The induction heating cooking according to claim 1, wherein the first electrode and the second electrode are each formed in a strip shape and are arranged at a substantially constant distance from an outer peripheral portion of the induction heating coil. vessel. The conductor is provided in the lower part of the top plate and is arranged near the outer periphery of the induction heating coil, and is arranged in different directions as viewed from the center of the first and second electrodes and the induction heating coil. A third electrode to be
A third capacitance detection unit that detects a change in capacitance of the third electrode;
The spillover determination unit determines that spillage has occurred when the capacitance detected by the third capacitance detection unit increases by a fifth predetermined value or more, and the third capacitance detection unit Even when the capacitance detected in step S3 increases by more than the fifth constant value, the first capacitance detection unit is simultaneously with the increase in capacitance detected by the third capacitance detection unit. When the capacitance detected in step 4 decreases by more than the fourth constant value or when the capacitance detected by the second capacitance detection unit decreases by more than the second predetermined value, The induction heating cooker according to claim 1 or 2, wherein it is not determined that occurrence has occurred.   The capacitance detected by the first capacitance detector increases by more than the first constant value, and the capacitance detected by the second capacitance detector is the second constant. Even if the value does not decrease more than the value, the capacitance detected by the third capacitance detection unit at the same time as the increase in capacitance detected by the first capacitance detection unit is equal to or more than a sixth constant value. The induction heating cooker according to claim 4, wherein when it is lowered, it is not determined that spilling has occurred.   The said 1st electrode, the said 2nd electrode, and the said 3rd electrode are each formed in strip | belt shape, and are arrange | positioned at a substantially constant distance from the outer peripheral part of the said induction heating coil. 4. The induction heating cooker according to 4.   The said 1st electrode, the said 2nd electrode, and the said 3rd electrode are each formed in strip | belt shape, and are arrange | positioned at a substantially constant distance from the outer peripheral part of the said induction heating coil. 5. The induction heating cooker according to 5.

Images