JP2014143121A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate discrimination of operations such as touching a pot or release of a pot during cooking, that can occur normally, from boiling-over, and to quickly perform determination.SOLUTION: An induction heating cooker comprises: a top plate 2; a heating coil 3; a heating coil holder 4; a high-frequency current supply part 5; a controller 6 controlling a heating operation; a plurality of electrodes 7 arranged on a lower surface of the top plate 2 and surrounding an outer peripheral part of the heating coil 3; a high-frequency signal generator 8 supplying a high-frequency signal to the electrode 7 via a capacitor; a DC voltage converter 9 receiving the high-frequency signal applied to the electrode 7 and converting it into a DC voltage; and a boiling-over detector 10. The lower surface of the top plate 2 has a conductor, and the heating coil holder 4 has an electrode at a ground potential connected with the conductor.

Description

  In particular, the present invention relates to an induction heating cooker that stabilizes a change in capacitance due to a person's movement or spillage that may occur during normal cooking, and improves spillover detection performance.

  Conventionally, this type of induction heating cooker has been blown down when the electrostatic capacity fluctuates from a predetermined value when there is no blown down due to contact with the electrodes arranged on the lower surface of the plate. And the circuit is stopped or the high-frequency current flowing through the heating coil is reduced (see, for example, Patent Document 1).

  FIG. 5 shows a conventional induction heating cooker described in Patent Document 1. As shown in FIG. As shown in FIG. 5, the induction heating device 16, the heating coil 17, the electrode 18, an AC power source 19, a drive circuit 20, a control circuit 21, and a capacitance measurement circuit 22 are configured.

JP 2008-159494 A

  However, in the above-described conventional configuration, the change in capacitance due to spilling increases or decreases depending on the spillage, the change in capacitance is difficult to stabilize, and it is difficult to determine the spilling. In addition, not only in the case of spilling but also in operations such as touching the pan during normal cooking and releasing the pan, the capacitance increased and decreased, and it was difficult to distinguish from spilling.

  In particular, in order to discriminate them, there is a problem that it takes time to detect the blow-down because it takes time to stabilize the change in capacitance.

  The present invention solves the above-described conventional problems, and makes it easy to discriminate from blown-down by not causing a change in capacitance in operations such as touching a pan during cooking that normally occurs, and releasing a pan. An object of the present invention is to provide an induction heating cooker that can improve the performance of blow-out detection by making a quick determination.

  In order to solve the above-described conventional problems, an induction heating cooker according to the present invention includes a top plate for placing a pan, a heating coil for heating the pan, a heating coil holder for holding the heating coil, and a high frequency for the heating coil. A high-frequency current supply unit that supplies current, a control unit that controls the heating operation of the high-frequency current supply unit, a plurality of electrodes that surround the outer periphery of the heating coil on the bottom surface of the top plate, and a high-frequency signal is supplied to the electrodes via a capacitor A high-frequency signal generator, a direct-current voltage converter that inputs a high-frequency signal applied to the electrode and converts it to a direct-current voltage, and the spillage of the liquid contained in the pan is measured from each output voltage of the high-frequency signal applied to each electrode. The bottom surface of the top plate has a conductor, and the heating coil holder has a ground potential electrode connected to the conductor. The output voltage is obtained by a stabilized.

As a result, a conductor is provided on the bottom surface of the top plate and the heating coil holder is connected to the ground potential even when there is an action such as spilling or touching the pan during cooking that the user can normally perform, or releasing the pan. Increased change in capacitance due to blown-down with a configuration with electrodes
The output voltage of the electrode is reduced only), and the separation performance between the blown-down and the normal operation of the user during cooking is improved, and the blowout is quickly determined.

  In the induction heating cooker of the present invention, the change in capacitance is stabilized when blown by a conductor provided on the lower surface of the top plate or the upper surface of the heating coil. For example, the capacitance change due to normal operation of the user who is not blown down, such as when the change in capacitance due to blown down is only increased (the output voltage of the electrode is decreased) and the user touches or releases the pan, etc. By eliminating the change, the determination becomes quicker, the separation performance between the spilling and the normal operation during cooking by the user is improved, and the usability is improved.

The block diagram which shows the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the top plate lower surface 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 output voltage of the electrode of the conventional induction heating cooking appliance The figure which shows the conventional induction heating cooking appliance

  1st invention supplies the high frequency current to the top plate 2 which mounts the pan 1, the heating coil 3 which heats the pan 1, the heating coil holder 4 which holds the heating coil 3, and the heating coil 3 A high-frequency current supply unit 5 that controls the heating operation of the high-frequency current supply unit 5, a plurality of electrodes 7 that surround the outer periphery of the heating coil 3 on the bottom surface of the top plate 2, A high-frequency signal generator 8 that supplies a high-frequency signal through a capacitor, a DC voltage converter 9 that inputs a high-frequency signal applied to the electrode 7 and converts it into a DC voltage, and a spill of liquid contained in the pan 1 A blow-off detector 10 that measures and detects each output voltage of the high-frequency signal applied to each of the electrodes, and the lower surface of the top plate 2 has a conductor 11, Zehnder 4 is obtained by the stabilizing output voltage by having the electrode 12 of the connected ground potential and the conductor 11.

  As a result, for example, only a change in capacitance due to blown down increases (the output voltage of the electrode 7 decreases), and a normal user of a blown down who does not blow down such as when the user touches or releases the pan 1 is used. Since the change in the capacitance due to the operation is eliminated, the determination becomes quick, the separation performance between the spilling and the normal operation during cooking by the user is improved, and the spilling quickly determines that the spilling is zero, leading to an improvement in usability.

  According to a second aspect of the invention, in particular, the lower surface of the top plate of the first aspect of the invention has a conductor, and the heating coil holder has an earth potential electrode connected to the conductor. Has a structure with a ground potential conductor on the top surface, making the determination quicker, improving the ability to distinguish between spilling and normal operation during cooking by the user, and quickly determining that spilling is zero. It leads to improvement.

  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 the bottom surface of the top plate of the induction heating cooker according to Embodiment 1 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 illustrating an output voltage of an electrode of a conventional induction heating cooker.

  In FIG. 1, the induction heating cooker according to the embodiment of the present invention includes a top plate 2 on which a pan 1 is placed, a heating coil 3 that heats the pan 1, a heating coil holder 4 that holds the heating coil 3, A high-frequency current supply unit 5 that supplies a high-frequency current to the heating coil 3, a control unit 6 that controls the heating operation of the high-frequency current supply unit 5, and a conductor disposed on the lower surface of the top plate 2, A plurality of surrounding linear electrodes 7, a high-frequency signal generating unit 8 for supplying a high-frequency signal to the electrode 7 via a capacitor, a DC voltage conversion unit 9 for inputting a high-frequency signal applied to the electrode 7 and converting it into a DC voltage, A blow-off detection unit 10 that detects the blow-out of the liquid stored in the pan 1 and an operation unit 13 that allows the user to instruct start / stop of heating, thermal power, and the like are provided.

  The top plate 2 is made of an electrical insulator such as glass and transmits infrared rays. The heating coil 3 is provided below the top plate 2. Further, the lower surface of the top plate 2 has a conductor 11 (for example, an electrode formed by carbon printing), and the heating coil holder 4 has an electrode 12 having a ground potential connected to the conductor 11 on the upper surface of the heating coil 3.

  The heating coil 3 is divided into two concentric circles to form an outer coil and an inner coil. A gap is provided between the outer coil and the inner coil. The pan 1 generates heat due to the eddy current generated by the high frequency magnetic field of the heating coil 3.

  Moreover, the display part 14 which displays states, such as a heating mode and a thermal power, between the operation part 13 and the pan 1 is provided.

  Moreover, it has the alerting | reporting part 15, and it is comprised with the speaker etc. for outputting the audio | speech data which notifies that the spilling occurred or the spilling was detected and the heating was stopped.

  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. The top plate 2 often uses crystallized glass, but is not limited thereto.

  The heating coil 3 is supplied with a high-frequency current from a high-frequency current supply unit 5 that operates according to an instruction from the control unit 6, and generates a high-frequency magnetic field by the current. 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.

  Since the heating coil holder 4 has the electrode 12 with the ground potential connected to the conductor 11, the energy that escapes to the ground via the electrode 12 is proportionally larger than the energy injected into the electrode 7 by heating or the like. Output voltage is stable.

For example, only a change in capacitance due to blown-down occurs (the output voltage of the electrode 7 decreases), and a static touch due to normal operation of a user who is not blown-down, such as when the user touches or releases the pan 1. Since there is no change in the capacitance, it is not necessary to consider the increase in the output voltage of the electrode 7 as a judgment at the time of blown down. It is easy to use by quickly determining that it has been blown down.

  Further, since the capacitance change is stabilized, the capacitance change pattern is reduced, the processing for determination is reduced, and the algorithm is simplified.

  The control unit 6 controls the high-frequency current supply unit 5 to perform a desired operation. When it is determined that the blown-down detection unit 10 has blown down, the high-frequency current supplied from the high-frequency current supply unit 5 is reduced or the heating is stopped.

  The electrode 7 is in contact with a conductor 11 formed on the lower surface of the top plate 2 by application or adhesion, and forms a capacitor with a pan on the top plate 2, a spilled liquid, a human body, or the like.

  Normally, there is nothing on the top plate 2, so air plays its role. However, when another object such as the pan 1, fingers, water, or an object to be cooked is on the top plate 2, the capacitance changes because the relative permittivity of each object is different from that of air.

  The blow-off detector 10 detects this change in capacitance. The blow-off detector 10 often detects by converting a change in capacitance into a change in DC voltage, but is not limited thereto.

  FIG. 2 is a diagram showing the lower surface of the top plate 2 of the induction heating cooker in the first embodiment of the present invention. As shown in FIG. 2, the top plate 2 includes a conductor 11 for the right electrode, the left electrode, and the rear electrode on the outer periphery of the heating coil 3 formed on the lower surface by coating or bonding, and a conductor 11 on the upper surface of the heating coil 3. Have.

  The conductor 11 is exemplified by carbon printing in this embodiment. However, the present invention is not limited to this, and a conductor having a ground potential may be placed on the back surface of the top plate. You may make it the structure pressed against.

  In FIG. 4, the output voltage of the electrode of the conventional induction heating cooking appliance when not implementing this invention is shown.

When the blow-off occurs, a first increase value (ΔV, for example, 15 digits) is generated with respect to the first reference value (V ₀ ) that is an output voltage when there is no blow-off. As the blown liquid approaches the conductor, the electrostatic capacity is stabilized in the direction in which the output voltage of the electrode decreases.

  By calculating these changes, it has been determined whether the operation is zero blowing or cooking by the user. As a result, malfunctions such as heating stoppage or reduction in heating power due to changes in capacitance when the user has not touched the pan 1 can be prevented, and the user can continuously cook. Was able to do.

  However, since it takes time until the change in capacitance is stabilized, there is a problem that the timing for detecting the blow-down is delayed.

  In FIG. 3, the output voltage of the electrode of the induction heating cooking appliance in Embodiment 1 of this invention is shown.

A first falling value (ΔV, for example, −15 digit) from the first reference value (V ₀ ), which is an output voltage when there is no blown down, can be calculated to determine whether blown down.

  By placing the conductor 11 with the ground potential on the lower surface of the top plate 2, the output voltage of the conventional electrode 7 does not increase, and when the user touches the pan 1, it blows away. The change in the electrostatic capacity at the time of not being lost is eliminated, and the change in the output voltage of the electrode 7 when the blow-off occurs is only reduced.

  Since the change in the output voltage of the electrode 7 is only reduced when it blows down, it is not necessary to determine when the output voltage of the electrode rises by an algorithm, and it is possible to determine and detect the blown out earlier than the conventional algorithm. .

  Here, “digit” indicates a value converted by the microcomputer, and 1 digit = 0.0195V.

  In addition, the conventional 1st rise value and 1st fall value ((DELTA) V) of this invention are also set to the value which can discriminate | determine the difference between the case where the user touches the pan 1 and the case where it actually blows down. It can be any other value.

  Note that the width, length, and shape of the right electrode, the left electrode, the back electrode, and the conductor in FIG. 2 are not limited to this, and the number, interval, and distance can be adjusted within a range to be detected. Shall.

  In addition, the lower surface of the top plate 2 in FIG. 2 has a conductor 11, and the heating coil holder 4 has an earth potential electrode 12 connected to the conductor 11. By having a conductor (not shown) connected to the electric potential and, for example, a lead wire, the separation performance between blowing down and normal operation during cooking by the user is improved, and it is quickly determined that blowing is done. You may make it lead to the improvement of usability.

  As described above, according to the induction heating cooker according to the present invention, it is possible to determine whether or not the blown down has occurred by stabilizing the capacitance change when blown by the conductor provided on the top plate lower surface or the heating coil upper surface. It is quick and has the effect of improving the ability to distinguish between blowing and normal operation during cooking, leading to improved usability, and is useful for induction heating cookers used in general households, etc. .

DESCRIPTION OF SYMBOLS 1 Pan 2 Top plate 3 Heating coil 4 Heating coil holder 5 High frequency current supply part 6 Control part 7 Electrode 8 High frequency signal generation part 9 DC voltage conversion part 10 Blow-down detection part 11 Conductor 12 Electrode 13 Operation part 14 Display part 15 Notification part 16 Induction Heating Device 17 Heating Coil 18 Electrode 19 AC Power Supply 20 Drive Circuit 21 Control Circuit 22 Capacitance Measurement Circuit

Claims (2)

A top plate for placing a pan, a heating coil for heating the pan, a heating coil holder for holding the heating coil, a high-frequency current supply unit for supplying a high-frequency current to the heating coil, and a high-frequency current supply unit A control unit that controls a heating operation; a plurality of electrodes that surround an outer periphery of the heating coil on a lower surface of the top plate; a high-frequency signal generation unit that supplies a high-frequency signal to the electrodes through a capacitor; and the electrode that is applied to the electrodes A DC voltage converter that inputs a high-frequency signal and converts it to a DC voltage, and a blow-off detector that measures and detects the blow-off of the liquid contained in the pan from each output voltage of the high-frequency signal applied to each of the electrodes And the lower surface of the top plate has a conductor, and the heating coil holder has an electrode of ground potential connected to the conductor. Induction heating cooker to stabilize the output voltages. 2. The heating coil has a ground potential conductor on an upper surface thereof, instead of the lower surface of the top plate having a conductor, and the heating coil holder has a ground potential electrode connected to the conductor. The induction heating cooker described in 1.