JP5828082B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that can avoid erroneous detection of blown-down due to a change in capacitance that may occur during cooking.

  Conventionally, when this type of induction heating cooker is in contact with an electrode disposed on the lower surface of the plate, the electrostatic capacity between the pan placed on the plate and the electrode does not have a zero blow. A change such as an increase or decrease from a predetermined value is detected. And when the fluctuation | variation of an electrostatic capacitance is detected, an induction heating cooking appliance determines that it has blown down, stops a circuit, or reduces the high frequency current sent through a heating coil (for example, refer patent document 1).

  FIG. 7 shows a conventional induction heating cooker described in Patent Document 1. As shown in FIG. 7, the conventional induction heating cooker includes a top plate 10 on which the pan 1 is placed, a heating coil 11, an electrode 12, an AC power supply 13, a drive circuit 14, and a control circuit 15. And the capacitance measuring circuit 16.

JP 2008-159494 A

  The capacitance may vary even when there is no blow-down. For example, even when an operation that can normally occur during cooking is performed such as when the user touches the pan or removes the pan, the capacitance may increase or decrease from a predetermined value when there is no spill. And in the conventional induction heating cooking appliance, the subject that the electrostatic capacitance fluctuation | variation accompanying the above-mentioned user's operation | movement may be erroneously determined as being blown down may occur.

  And when a false detection generate | occur | produced, the subject that a user cannot continue cooking occurred.

  The present invention solves the above-mentioned conventional problems, for example, avoids misdetection due to fluctuations in capacitance due to the operation of the user touching or releasing the pan, and thereby cooking continuously. It aims at providing the induction heating cooking appliance which can perform.

  In order to solve the conventional problems, an induction heating cooker of the present invention includes a top plate on which a pan is placed, a heating coil that heats the pan, and a high-frequency current supply unit that supplies a high-frequency current to the heating coil. A control unit that controls the heating operation of the high-frequency current supply unit, a plurality of electrodes that are linearly formed on the lower surface of the top plate and surround the outer periphery of the heating coil, and a high-frequency signal is transmitted to each of the electrodes via a capacitor. The high-frequency signal generator to be supplied, the DC voltage converter that inputs the high-frequency signal applied to each electrode and converts the high-frequency signal into a DC voltage for each electrode, and the output voltage of the DC voltage converter is contained in the pan. A blow-off detection unit that detects the blow-off of the liquid, and the blow-off detection unit outputs an output when the output voltage of any one of the plurality of electrodes is not blown down. After the reference value, which is a voltage, rises by more than the first increase value, the output voltage of at least one of the remaining electrodes is determined for each remaining electrode from the reference value within the first predetermined time. If it rises above the rise value, it is determined that no blow-off has occurred, and if all output voltages of the remaining electrodes do not rise above the second rise value from the reference value within the first predetermined time Then, it is determined that the blow-off has occurred.

  The present invention relates to variations in capacitance that can occur during normal cooking, for example, variations in capacitance when the user does not spill, such as when the user touches or does not touch the pan during cooking, and spills. It pays attention to the fact that it differs from the mode of variation in capacitance. That is, in the case of blown-down, after the output voltage of any one of the plurality of electrodes rises by more than the first increase value from the reference value that is the output voltage when there is no blown-down, the first predetermined time In addition, all the output voltages of the remaining electrodes do not increase more than the second increase value from the reference value. On the other hand, when it is not blown down, for example, when the user touches the pan during cooking, the output voltage of any one of the plurality of electrodes is the output voltage when there is no blown down. After rising from a reference value by a first increase value or more, the output voltage of at least one of the remaining electrodes rises from the reference value by a second increase value or more within a first predetermined time. In the present invention, based on such knowledge, it is determined whether or not the blowing is zero. According to the present invention, the fluctuation in capacitance that can occur during normal cooking, for example, the error in detection of blown-down due to the fluctuation in capacitance when the user does not blow-down, such as when the user touches the pan, is detected. Operation can be prevented.

  The induction heating cooker according to the present invention has a capacitance fluctuation that can occur during normal cooking, for example, a spill due to a change in the capacitance when the spill is not zero, such as when the user touches the pan. Detection malfunction can be prevented. Thereby, it becomes possible for a user to cook continuously, and usability can be improved.

The block diagram which shows the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the electrode example of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the output voltage of the electrode of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the other form of the electrode of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the output voltage of the electrode of the induction heating cooking appliance in Embodiment 2 of this invention The figure which shows the output voltage of the electrode of the induction heating cooking appliance in Embodiment 3 of this invention The figure which shows the conventional induction heating cooking appliance

  Each invention of the present application describes variations in capacitance that can occur during normal cooking, for example, variations in capacitance when the user does not spill, such as when the user touches or does not touch the pan during cooking. It pays attention to the fact that it differs from the mode of capacitance fluctuation due to spilling. That is, in the case of blown-down, after the output voltage of any one of the plurality of electrodes rises by more than the first increase value from the reference value that is the output voltage when there is no blown-down, the first predetermined time In addition, all the output voltages of the remaining electrodes do not increase more than the second increase value from the reference value. On the other hand, when it is not blown down, for example, when the user touches the pan during cooking, the output voltage of any one of the plurality of electrodes is the output voltage when there is no blown down. After rising from a reference value by a first increase value or more, the output voltage of at least one of the remaining electrodes rises from the reference value by a second increase value or more within a first predetermined time. In the present invention, based on such knowledge, it is determined whether or not the blowing is zero. According to the present invention, the fluctuation in capacitance that can occur during normal cooking, for example, the error in detection of blown-down due to the fluctuation in capacitance when the user does not blow-down, such as when the user touches the pan, is detected. Operation can be prevented.

  An induction heating cooker according to a first invention includes a top plate on which a pan is placed, a heating coil that heats the pan, a high-frequency current supply unit that supplies a high-frequency current to the heating coil, and the high-frequency current supply unit A control unit that controls the heating operation of the electrode, a plurality of electrodes that are linearly formed on the lower surface of the top plate and surround the outer periphery of the heating coil, and a high-frequency signal generator that supplies a high-frequency signal to each of the electrodes via a capacitor A DC voltage converter that inputs the high-frequency signal applied to each electrode and converts it into a DC voltage for each electrode; and a spill of liquid stored in the pan based on the output voltage of the DC voltage converter A blow-off detector that detects whether the output voltage of any one of the plurality of electrodes is a reference value that is an output voltage when there is no blow-down When the output voltage of at least one of the remaining electrodes rises by more than a second rise value determined for each remaining electrode from the reference value within a first predetermined time after rising by the first rise value or more Determines that no blow-off has occurred, and if all the output voltages of the remaining electrodes do not rise more than the second increase value from the reference value within the first predetermined time, blow-off has occurred. It is determined that This prevents capacitance fluctuations that may occur during normal cooking, for example, malfunctions in the detection of blown-down due to fluctuations in capacitance when the user is not blown away from touching the pan. be able to. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  In the induction heating cooker according to the second invention, the electrode of the first invention is formed in an arc shape and disposed along the outer periphery of the heating coil. Accordingly, it is possible to more accurately discriminate between the case where the user has come out of the state where the user touches the pan and the case where the liquid is blown from the pan. In addition, it is possible to prevent malfunctions in detection of blown-down due to fluctuations in capacitance that may occur during normal cooking, for example, when the user does not blow-down when the user touches the pan. Can do. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  An induction heating cooker according to a third aspect of the present invention is directed to the blow-off detection unit of the induction heating cooker according to the first or second aspect of the invention, wherein the output voltage of any one of the plurality of electrodes is When all output voltages of the remaining electrodes rise from the reference value by more than the second increase value within the first predetermined time after rising from the reference value by the first increase value or more, blow-off has occurred. It is configured to determine that there is no. This makes it more accurate when the pan is placed in the center of the multiple electrodes and when the user touches the pan and when the liquid is blown from the pan. Can be determined. In addition, it is possible to prevent malfunctions in detection of blown-down due to fluctuations in capacitance that may occur during normal cooking, for example, when the user does not blow-down when the user touches the pan. Can do. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  In the induction heating cooker according to the fourth aspect of the invention, in the induction heating cooker according to the first or second aspect of the invention, the blown-off detection unit has an output voltage of any one of the plurality of electrodes, When the output voltage of at least two of the remaining electrodes rises from the reference value by a predetermined increase value after the first increase value from the reference value by the first increase value or more. Then, it is determined that no blow-off has occurred, and the predetermined increase value and the first increase value are made different from each other. As a result, even when the pan is placed in a state shifted in one direction instead of the central portion of the plurality of arranged electrodes, the case where the user has come out of the state of touching the pan, and the pan Thus, it is possible to more accurately determine the case where the liquid has been blown down. In addition, it is possible to prevent malfunctions in detection of blown-down due to fluctuations in capacitance that may occur during normal cooking, for example, when the user does not blow-down when the user touches the pan. Can do. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  In the induction heating cooker according to the fifth aspect of the invention, in the induction heating cooker according to the first or second aspect of the invention, the blow-off detection unit has an output voltage of any one of the plurality of electrodes, This is a case where the output voltage of at least one of the remaining electrodes rises from the reference value by the second rising value after the first rising value from the reference value by the first rising value or more. However, it is not immediately determined whether or not the blow-off has occurred, and the output voltage of any one of the plurality of electrodes is further within a second predetermined time after the first predetermined time has elapsed. When the output voltage of at least one of the remaining electrodes rises from the reference value by the second rising value after the first rising value from the reference value by the first rising value or more. For the first time, blown out It determined that there is no. Thereby, it can be detected that the user is touching the pan intermittently for the second predetermined time. Therefore, it is possible to determine the presence or absence of blow-off more accurately. In addition, it is possible to prevent malfunctions in detection of blown-down due to fluctuations in capacitance that may occur during normal cooking, for example, when the user does not blow-down when the user touches the pan. Can do. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  An induction heating cooker according to a sixth invention is the induction heating cooker according to any one of the first, second, third, and fifth inventions, wherein the first increase value and the second increase value are: It is the same value. Thereby, the structure of an induction heating cooking appliance can be made simple.

  An induction heating cooker according to a seventh invention is the induction heating cooker according to any one of the first to sixth inventions, wherein the blown-down detector is determined not to be blown down by the blown-down detector. Thereafter, the blow-off detection is disabled for a third predetermined time. Thereby, the user during cooking can cook more comfortably without stopping 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)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating an induction heating cooker according to Embodiment 1 of the present invention.

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

  FIG. 3 is a diagram showing an output voltage of an electrode of the induction heating cooker in the first embodiment of the present invention.

  FIG. 4 is a diagram showing another form of the electrode of the induction heating cooker in the first embodiment of the present invention.

  As shown in FIG. 1, the induction heating cooker according to the first embodiment of the present invention includes a top plate 2, a heating coil 3, a high-frequency current supply unit 4, a control unit 5, a plurality of electrodes 6, and a high-frequency signal generation unit 7. A DC voltage converter 8 and a blow-off detector 9. The pan 1 is placed on the top plate 2. The heating coil 3 heats the pan 1. The high frequency current supply unit 4 supplies a high frequency current to the heating coil 3. The control unit 5 controls the heating operation of the high-frequency current supply unit 4. The plurality of electrodes 6 are linearly formed on the lower surface of the top plate 2 and are arranged so as to surround the outer periphery of the heating coil 3 in a polygonal shape. As shown in FIG. 2, each electrode 6 has, for example, a width T = 1.5 cm and a length L = 5 cm, and is formed in a linear shape (linear shape). Further, in the electrode 6, a line connecting one end of the electrode 6 and the center of the heating coil 3 and a line connecting the other end of the electrode 6 and the center of the heating coil 3 form an angle θ = 30 degrees at the center of the heating coil 3. Thus, it arrange | positions along the outer peripheral part of the heating coil 3 at circular arc shape. The high frequency signal generator 7 supplies a high frequency signal to the electrode 6 via the capacitor C. The DC voltage conversion unit 8 inputs a high frequency signal applied to each electrode 6 and converts it into a DC voltage for each electrode 6. The blown-off detection unit 9 detects the blown-down of the liquid stored in the pan 1 based on the output voltage of the DC voltage conversion unit 8. When the common potential of the high-frequency signal generation unit 7, the DC voltage conversion unit 8, and the blow-off detection unit 9 is an unstable potential with respect to the ground (ground), the detection voltage increases with respect to the reference value due to blow-down. There is a case. Even in this case, the induction heating cooker of the present embodiment can detect the rise of the detection voltage and detect the blow-off.

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

  The pan 1 is placed on a top plate 2 that forms part of the outline of the induction heating cooker. At that time, the pan 1 is placed at a position facing the heating coil 3 across the top plate 2. The top plate 2 is often formed of crystallized glass, but is not limited thereto.

  The heating coil 3 is supplied with a high frequency current and generates a high frequency magnetic field by the current. The high-frequency current is supplied from a high-frequency current supply unit 4 that operates according to instructions from the control unit 5. An eddy current is generated in the pan 1 that has received a high-frequency magnetic field, and the pan 1 is heated by the eddy current.

  The control unit 5 controls the high-frequency current supply unit 4 to perform a desired operation. When the blow-off detection unit 9 detects the blow-down, the control unit 5 reduces the thermal power by reducing the high-frequency current supplied from the high-frequency current supply unit 4 or supplies the high-frequency current from the high-frequency current supply unit 4. The heating is stopped by stopping the heating.

  The electrode 6 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. Since there is usually nothing on the top plate 2, a capacitor is formed by the electrode 6 and air. However, when another object such as the pan 1, the user's finger, 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.

  The blow-off detector 9 is configured such that the output voltage of any one of the plurality of electrodes 6 is a first increase value ΔV from a first reference value V0, which is an output voltage when there is no blow-through (claims). After the rise (corresponding to the first rise value in the range), the output voltage of at least one of the remaining electrodes 6 within the first predetermined time is changed from the first reference value V0 to the first rise value ΔV (claims). If it rises above (corresponding to the second rise value in the range of 1), it is determined that no blow-off has occurred, and all the output voltages of the remaining electrodes 6 within the first predetermined time are from the first reference value V0. When it does not increase more than the first increase value ΔV (corresponding to the second increase value in the claims), it is determined that the blow-off has occurred.

  Specifically, the blow-off detection unit 9 detects a change in capacitance based on the output voltage of the DC voltage conversion unit 8. In addition, when the blow-off detection unit 9 determines that the blow-out is not zero, the blow-off detection is invalidated for 10 seconds (third predetermined time) after the determination. The reason for disabling is that there is a high possibility that the user is cooking. By disabling in this way, a user during cooking can cook more comfortably without stopping heating. Although many of the blow-off detection units 9 detect changes by converting a change in capacitance into a change in DC voltage, the present invention is not limited to this.

  The blow-off detection unit 9 measures each output voltage of the DC voltage conversion unit 8 for each of the plurality of electrodes 6 and determines the presence or absence of blow-off based on the output voltage. Specifically, the blow-off detection unit 9 determines whether or not the measured output voltage of any one of the plurality of electrodes 6 has increased by a first increase value ΔV or more from the first reference value V0. To do. The first reference value V0 is an output voltage when there is no blow-down. The first increase value ΔV is, for example, 15 digits. “Digit” indicates a value converted by the microcomputer, and 1 digit = 0.0195V.

  When the output voltage of any one of the electrodes 6 increases from the first reference value V0 by the first increase value ΔV or more as shown in FIG. 3, the blow-off detector 9 detects the electrode 6 whose voltage has increased first (hereinafter referred to as appropriate). It is determined whether or not the output voltage of the other electrode 6 has increased from the first reference value V0 by the first increase value ΔV or more during the first predetermined time from the increase of the voltage of the “trigger electrode”.

  Then, when the output voltage of the other electrode 6 increases from the first reference value V0 by the first increase value (ΔV) or more as shown in FIG. 3, the blow-off detector 9 determines that no blow-off has occurred. To do. On the other hand, if the output voltage of the other electrode 6 has not increased from the first reference value V0 by the first increase value (ΔV) or more, the blow-off detection unit 9 determines that blow-off has occurred.

  In other words, the increase of the first increase value ΔV or more starts from the increase of the output voltage at the trigger electrode in at least two or more electrodes 6 including the electrode 6 that has first increased among the plurality of electrodes 6. If it occurs within one predetermined time (for example, 0.5 seconds), it is determined that the blow is not zero. Thereby, malfunctions, such as a heating stop by the change of an electrostatic capacitance when it is not blown down, such as a case where the user touched the pan 1, and a decrease in thermal power, can be prevented. And it becomes possible for a user to cook continuously and to improve usability. Further, after it is determined that it is not blown down, the blown down detection is disabled for the third predetermined time (for example, 10 seconds) in order to further prevent the occurrence of erroneous detection.

  Note that the first predetermined time is set to a value that can distinguish the difference between when the user touches the pan 1 and when the user actually blows down, and may be simultaneously (0 seconds). And

  The first increase value (ΔV) is also set to a value that can distinguish the difference between the case where the user touches the pan 1 and the case where the user actually blows down, and other values may be used. Shall.

  Although the plurality of electrodes 6 are provided on the lower surface of the top plate 2 as described above, the structure and arrangement of the electrodes 6 may be restricted depending on the arrangement relationship with other constituent members, for example. Depending on the structure and arrangement of the electrodes 6, the impedance of the plurality of electrodes 6 may differ for each electrode 6. In this case, in order to detect the blow-off at each electrode 6 with the same sensitivity, the first increase value ΔV (the first increase value and the second increase value in the claims) is set for each electrode 6. What is necessary is just to set to the value according to the impedance of the electrode 6. FIG. That is, the first increase value ΔV (the first increase value and the second increase value in the claims) may be different for each electrode 6. By configuring in this way, even when the impedance of the plurality of electrodes 6 differs for each electrode 6, it is possible to accurately detect blow-off. In addition, it is possible to more accurately discriminate between the case where the user touches the pan 1 and the state where the user has touched the pan 1 and the case where liquid has blown from the pan 1. This technical idea is also applicable to the third embodiment.

  In the present embodiment, the output voltage of any one of the plurality of electrodes 6 is changed from the first reference value V0, which is the output voltage when there is no blow-down, to the first increase value ΔV (in the claims) At least one of the rise value (corresponding to the first rise value in the claims) when determining that it has risen (corresponding to the first rise value) and the remaining electrodes 6 within the first predetermined time thereafter The increase value (corresponding to the second increase value in the claims) when determining that the output voltage of one electrode 6 has increased from the first reference value V0 is the same value as the first increase value ΔV. . Thereby, the structure of an induction heating cooking appliance can be made simple. The first increase value and the second increase value may be different values. This technical idea can also be applied to the third embodiment.

  In the present embodiment, the electrode 6 is configured as shown in FIG. 2, but may be configured as shown in FIG. That is, as shown in FIG. 4, the electrodes 6 are formed in an arc shape, and three electrodes 6 are arranged around each heating coil 3 so as to be along the outer periphery of the heating coil 3. Specifically, the electrode 6 is formed in an arc shape with, for example, a width T = 1.5 cm, a length L = 10 cm, and an angle θ = 120 degrees. The electrode 6 has an angle θ formed by a line connecting one end of the electrode 6 and the center of the heating coil 3 and a line connecting the other end of the electrode 6 and the center of the heating coil 3 at the center of the heating coil 3. They are formed and arranged so that θ = 120 degrees. By setting it as such a structure, the distance from the center part of the heating coil 3 to the electrode 6 becomes equal. Thereby, compared with the case where the electrodes 6 are arranged in a polygonal shape as shown in FIG. 2, there is no spillage such as when the user touches the pan 1 placed at the center of the heating coil 3. The change in capacitance at the time and the change in capacitance when the liquid is blown from the pan 1 can be more accurately discriminated.

  2 and 4, the width T and length L of the electrode 6 and the angle θ with respect to the center of the heating coil 3 are not limited to this, but the number of electrodes 6, the distance between the electrodes 6, and the electrodes The distance between the arc 6 and the arc of the heating coil 3 can be appropriately adjusted according to the range to be detected.

  As described above, according to the present embodiment, the capacitance fluctuation that can occur during normal cooking, for example, the capacitance when the user does not blow down, such as when the user touches the pan 1, is removed. It is possible to prevent malfunction of the blow-off detection due to fluctuation. A more specific example will be described. When the user touches the pan 1, for example, the blowout detection is detected when the capacitance decreases and the output voltage increases with respect to the reference value. Can prevent malfunction. Thus, according to this embodiment, it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  In each of the above embodiments, the blow-off detection unit 9 causes the output voltage of one electrode 6 to increase from a first reference value V0, which is an output voltage when there is no blow-down, to a first increase value ΔV (in the claims) After rising above (corresponding to the first rising value), all the output voltages of the remaining electrodes 6 during the first predetermined time have the first rising value ΔV (corresponding to the second rising value in the claims). When it rises above, you may comprise so that it may determine with it not being blown down. According to this configuration, when the pan 1 is placed at the center of the plurality of electrodes 6, the liquid comes from the pan 1 when the user touches the pan 1. The case where it blows down can be determined more correctly. Moreover, the malfunction of the electric blower detection by the fluctuation | variation of the electrostatic capacitance which may occur at the time of normal cooking, for example, when it is not blown down when the user touches the pan 1, for example, is prevented. be able to. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to the drawings.

  FIG. 5 is a diagram showing the output voltage of the electrodes in the second embodiment of the present invention.

  Note that description of the same components and operations as those of the first embodiment is omitted.

  In the present embodiment, the blow-off detection unit 9 has a first increase in the output voltage of any one of the plurality of electrodes 6 from the first reference value V0 that is an output voltage when there is no blow-down. If the output voltage of at least two of the remaining electrodes 6 rises by more than the predetermined reference values V0 and ΔV3 from the first reference value V0 within the first predetermined time after increasing by the value ΔV1 or more, It is determined that no spill has occurred. Then, the respective predetermined increase values ΔV2 and ΔV3 are made different from the first increase value delta V1.

  Specifically, the blown-off detection unit 9 has a first increase value ΔV1 (for example, 13 digit), a second increase value ΔV2 (for example, 10 digit), and a third increase value ΔV3 (for example, 7 digit) as the increase values for determination. Use different types of values. Then, the blown-off detector 9 detects two of the remaining electrodes 6 within a first predetermined time (for example, 0.5 seconds) started from an increase in the output voltage of the trigger electrode equal to or higher than the first increase value ΔV1. When the output voltage rises equal to or higher than the second rise value ΔV2 and the third rise value ΔV3 occurs in the two electrodes 6, it is determined that the blowing is not zero. That is, even when the pan 1 is placed in a state shifted in one direction instead of the central portion of the plurality of electrodes 6 by providing a plurality of increase values ΔV1, ΔV2, ΔV3 for determination, it is used. The blow-off detection unit 9 can more accurately determine when the person has touched the pan 1 and when the liquid is blown from the pan 1.

  Note that the first predetermined time is set to a value that can distinguish the difference between when the user touches the pan 1 and when the user actually blows down, and may be simultaneously (0 seconds). And

  The first increase value (ΔV) is also set to a value that can distinguish the difference between the case where the user touches the pan 1 and the case where the user actually blows down, and other values may be used. Shall.

  According to this embodiment, even when the pan 1 is placed in various places, the capacitance fluctuation that can occur during normal cooking, for example, the state where the user touches the pan 1 has been removed. It is possible to prevent malfunction of blown-off detection due to fluctuations in the capacitance when the blown-out is not caused. And it becomes possible for a user to cook continuously and it leads to the improvement of usability.

  As described in the first embodiment, the impedance of the plurality of electrodes 6 may differ for each electrode 6 depending on the structure and arrangement of the electrodes 6. Therefore, in order to detect the blow-off at each electrode 6 with the same sensitivity, the first increase value ΔV1 (first increase value in the claims), the second and third increase values ΔV2, ΔV3 (claims) For each electrode 6 may be set to a value corresponding to the impedance of each electrode 6. By configuring in this way, even when the impedance of the plurality of electrodes 6 differs for each electrode 6, it is possible to accurately detect blow-off. In addition, it is possible to more accurately discriminate between the case where the user touches the pan 1 and the state where the user has touched the pan 1 and the case where liquid has blown from the pan 1.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to the drawings.

  FIG. 6 is a diagram showing the output voltage of the electrodes in the third embodiment of the present invention.

  Note that description of the same components and operations as those of the first embodiment is omitted.

  In the present embodiment, the blow-off detection unit 9 has a first reference value V0 that is an output voltage when the output voltage of any one of the plurality of electrodes 6 is not blown down (claims). The output voltage of at least one of the remaining electrodes 6 from the first reference value V0 to the first value within the first predetermined time after the first increase value ΔV is increased from the first reference value V0. Even if it rises above the rise value ΔV (corresponding to the second rise value in the claims), it is not immediately determined whether or not a blow-off has occurred. The blow-off detection unit 9 further detects that the output voltage of any one of the plurality of electrodes 6 from the first reference value V0 to the first is within the second predetermined time after the first predetermined time has elapsed. After rising by a rise value ΔV (corresponding to the first rise value in the claims) or more, the output voltage of at least one of the remaining electrodes 6 from the first reference value V0 within the first predetermined time. It is determined that no blow-off has occurred until the first rise value ΔV (corresponding to the second rise value in the claims) is exceeded. That is, after the output voltage of any one of the plurality of electrodes 6 rises by more than the first increase value ΔV from the first reference value V0 that is the output voltage when there is no blown down, the first predetermined time If a phenomenon in which a voltage increase equal to or greater than the first increase value ΔV occurs repeatedly in at least one of the remaining electrodes 6, the blow-off detection unit 9 determines that the blow-out is not zero.

  Specifically, as shown in FIG. 6, the blow-off detection unit 9 calculates a first increase value ΔV from the first reference value V0 that is an output voltage when there is no blow-down. The blow-off detector 9 detects the first of the electrodes other than the trigger electrode within a first predetermined time (for example, 0.5 seconds) that starts from a voltage increase equal to or higher than the first increase value ΔV (for example, 15 digit) of the trigger electrode. A voltage increase of at least two times (including a voltage increase of the trigger electrode) occurs at a voltage increase of the increase value ΔV (for example, 15 digits) or more, and further, a second predetermined time (for example, 10 seconds) after the first predetermined time has elapsed. ) Within a first predetermined time starting from a voltage rise of a first rise value ΔV (for example, 15 digits) or more at the trigger electrode, the first rise value ΔV or more from the first reference value V0 at the electrodes other than the trigger electrode. When the output voltage rises at least twice (including the trigger electrode voltage rise), it is determined that the blowout is not zero. Thereby, it can be determined that the user is performing a cooking operation in which the pan is moved or touched around the induction heating cooker. It should be noted that the blow-off detection may be disabled during the third predetermined time (for example, 60 seconds) after the determination in order to further prevent erroneous detection.

  Note that the first predetermined time is set to a value that can distinguish the difference between when the user touches the pan 1 and when the user actually blows down, and may be simultaneously (0 seconds). And

  The first increase value (ΔV) is also set to a value that can distinguish the difference between the case where the user touches the pan 1 and the case where the user actually blows down, and other values may be used. Shall.

  According to the present embodiment, it can be detected that the user is touching the pan intermittently for the second predetermined time. Therefore, it is possible to determine the presence or absence of blow-off more accurately. Capacitance fluctuations that can occur during normal cooking, such as when the user touches the pan 1, such as when the user blows away, prevents malfunctions in the blowout detection due to changes in the capacitance when the blowout is not zero. , The user can continuously cook, leading to improved usability.

  In the present embodiment, as shown in FIG. 6, the electrode 6 (trigger electrode) whose output voltage first increased and the electrode 6 whose output voltage increased third are the same electrode, but different electrodes. It may be. The second electrode 6 with the increased output voltage and the fourth electrode 6 with the increased output voltage are the same electrode, but may be different electrodes. By comprising in this way, even when a user touches or makes the pan in various directions, the case where the user is separated from the state where the user touches the pan 1, and the pan It is possible to accurately determine when the liquid has been blown from 1.

  According to the induction heating cooker of the present invention, the electrodes are arranged so as not to hinder the operation and cleanability of the equipment. As a result, the blow-off detection function can be reliably detected, and the blow-off detection function can be prevented from malfunctioning due to a change in capacitance when the user has not touched the pan. be able to. Thereby, the induction heating cooker of this invention becomes possible [a user can cook continuously] and has an effect that usability improves. The present invention is useful for induction heating cookers used in general households.

DESCRIPTION OF SYMBOLS 1 Pan 2 Top plate 3 Heating coil 4 High frequency current supply part 5 Control part 6 Electrode 7 High frequency signal generation part 8 DC voltage conversion part 9 Blow down detection part

Claims (7)

A top plate on which the pan is placed;
A heating coil for heating the pan;
A high-frequency current supply unit for supplying a high-frequency current to the heating coil;
A control unit for controlling the heating operation of the high-frequency current supply unit;
A plurality of electrodes formed linearly on the lower surface of the top plate and surrounding an outer periphery of the heating coil;
A high-frequency signal generator for supplying a high-frequency signal to each of the electrodes via a capacitor;
A DC voltage converter that inputs the high-frequency signal applied to each electrode and converts the high-frequency signal into a DC voltage for each electrode;
A blown-down detection unit that detects the blown-down of the liquid stored in the pan based on the output voltage of the DC voltage conversion unit,
With
The blow-off detector detects a first predetermined time after the output voltage of any one of the plurality of electrodes has increased by a first increase value or more from a reference value that is an output voltage when there is no blow-down. If the output voltage of at least one of the remaining electrodes rises from the reference value by a second rising value determined for each remaining electrode, it is determined that no blow-off has occurred, If all the output voltages of the remaining electrodes within the first predetermined time do not increase more than the second increase value from the reference value, it is determined that blow-off has occurred,
Induction heating cooker. The electrode is formed in an arc shape and disposed along the outer periphery of the heating coil.
The induction heating cooker according to claim 1. The blow-off detector detects all the remaining electrodes within the first predetermined time after the output voltage of any one of the plurality of electrodes has increased from the reference value by the first increase value or more. When the output voltage of the output rises from the reference value by the second increase value or more, it is determined that no blow-off has occurred.
The induction heating cooker according to claim 1 or 2. The blow-off detection unit is configured such that after the output voltage of any one of the plurality of electrodes rises from the reference value by the first increase value or more, the remaining electrode within the first predetermined time period. When the output voltage of at least two of the electrodes rises from the reference value by a predetermined increase value or more, it is determined that no blow-off has occurred,
Each of the predetermined increase value and the first increase value are different from each other;
The induction heating cooker according to claim 1 or 2. The blow-off detector detects an output voltage of any one of the plurality of electrodes from among the remaining electrodes within the first predetermined time after the output voltage rises from the reference value by the first increase value or more. Even when the output voltage of at least one of the electrodes rises from the reference value by the second increase value or more, it is not immediately determined whether or not a blow-off has occurred, and after the first predetermined time has elapsed The output voltage of any one of the plurality of electrodes further rises from the reference value by the first rising value or more after the second predetermined time, and then the remaining electrodes within the first predetermined time. Only when the output voltage of at least one of the electrodes rises from the reference value by the second rise value or more, it is determined that no blow-off has occurred.
The induction heating cooker according to claim 1 or 2. The first increase value and the second increase value are the same value.
The induction heating cooker according to any one of claims 1, 2, 3, and 5. The blow-off detection unit invalidates blow-off detection for a third predetermined time after determining that it is not blow-down.
The induction heating cooker according to any one of claims 1 to 6.

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