JP2005353533A - Induction heating cooking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooking device which can control accurately an induction heating means based on the true temperature of a cooking vessel by suppressing the influence of induction heating to a temperature detector. <P>SOLUTION: The outputs of three temperature detectors 18-20 are given to a controller 35. The controller 35 supplies a high frequency current to an induction heating coil 3 through an inverter circuit 36. A current transformer 44 is inserted to the output side of the inverter circuit 36. The secondary side output voltage of the current transformer 44 is given to the controller 35 through an inverter current detector 45. The controller 35 corrects the detected temperatures of the temperature detectors 18-20 according to the inverter current value given from the inverter current detector 45. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an induction heating cooker including a temperature detection unit that detects the temperature of a cooking container placed on a top plate.

  An induction heating cooker called an IH cooking heater includes an induction heating coil, an inverter device that supplies high-frequency power to the induction heating coil, and a top plate that is disposed above the induction heating coil and on which a cooking container such as a pan is placed. I have. In such an induction heating cooker, the temperature of the cooking container is detected by a plurality of temperature detection elements disposed under the top plate, and the drive of the inverter device is controlled based on the detection result. Has been.

In this case, if the difference between the actual temperature of the cooking pot and the detected temperature of the temperature detecting element is large, or if the detected temperatures of the plurality of temperature detecting elements vary, the inverter heating device can accurately drive the induction heating coil. It cannot be controlled well. Therefore, in the conventional induction heating cooker, a heat sensitive member for efficiently and uniformly transmitting the temperature of the pan to the temperature detecting element is interposed between the top plate and the temperature detecting element.
Japanese Patent No. 3044826

However, the temperature detecting element and the heat sensitive member are induction heated by magnetic flux generated by the current flowing through the induction heating coil. The influence of induction heating by the induction heating coil differs depending on the position of the temperature detection element. For this reason, there has been a problem that a large error occurs in the detected temperature of the temperature detecting element.
Accordingly, an object of the present invention is to provide an induction heating cooker that can suppress the influence of induction heating on the temperature detection unit and can accurately control the induction heating means based on the true temperature of the cooking container.

  An induction heating cooker of the present invention includes an induction heating means having an induction heating coil and an inverter circuit for supplying a high frequency current to the induction heating coil, and a top plate provided above the induction heating coil and on which a cooking vessel is placed. A temperature detection unit disposed between the top plate and the induction heating coil, a heat generation amount detection unit for detecting a heat generation amount of the temperature detection unit, an output of the temperature detection unit and the heat generation amount detection unit And a control means for controlling the induction heating means based on the output of. The calorific value detection means detects the calorific value of the temperature detection unit based on at least one of input current and input power of the inverter circuit and current and power supplied from the inverter circuit to the induction heating coil. .

  In the above configuration, the heat generation amount of the temperature detection unit induction-heated by the current flowing through the induction heating coil is detected by the heat generation amount detection unit, and the induction heating unit is controlled based on the detected heat generation amount and the output of the temperature detection unit. The

  Since the present invention can suppress the influence of induction heating of the temperature detection unit by the induction heating coil, the induction heating means can be accurately controlled based on the true temperature of the cooking container.

Hereinafter, an embodiment in which the present invention is applied to an induction heating cooker incorporated in a system kitchen will be described with reference to the drawings.
FIG.1 and FIG.2 shows the whole structure of the heating cooker based on a present Example. In these drawings, the heating cooker body 1 includes an upper unit 1a fitted into the cooking table 2 from above, and a lower unit 1b located below the upper unit 1a and fitted into the cooking table 2 from the front. It is composed of.

The upper unit 1a includes a case 6 that accommodates induction heating coils 3 and 4 and a radiant heater 5 as heating means, and a top plate 7 that closes an upper surface opening of the case 6. The top plate 7 is disposed on the case 6 while being supported by the outer frame 7a. An exhaust port 7b is formed at the rear of the outer frame 7a.
In the front part of the top surface of the top plate 7, induction heating parts 8 and 9 are provided side by side corresponding to the induction heating coils 3 and 4. In the center of the rear portion of the top plate 7, a heater heating unit 10 is provided corresponding to the radiant heater 5. A pan P (see FIG. 3), which is a cooking container, is placed on the heating units 8-10. On the top surface of the top plate 7, a circular frame portion that defines the area of each heating unit 8 to 10 is printed.

The induction heating cooker according to the present embodiment is referred to as a “wide top plate” type in which the width dimension of the top plate 7 is larger than the conventional one, and a large pan such as a wok is attached to the heating units 8 and 9. Even if it is placed, the pan does not protrude from the top plate 7.
Coil output display portions 11 and 12 for displaying the output states of the induction heating coils 3 and 4 are provided in front of the induction heating portions 8 and 9 in the top plate 7. In addition, a heater output display unit 13 for displaying the output state of the radiant heater 5 is provided at the center of the front portion of the top plate 7.

On the other hand, the case 6 includes a thin rectangular box-shaped housing portion 6a for housing the induction heating coils 3 and 4 and the radiant heater 5, and a flange 6b projecting upward and leftward. The accommodating portion 6 a is fitted into the cooking table 2 through a rectangular opening 2 a formed in the cooking table 2, and the flange 6 b is placed on the cooking table 2.
The induction heating coils 3, 4 and the radiant heater 5 are all mounted on a support base 15 disposed below the induction heating units 8, 9 and the heater heating unit 10 in the housing 6 a. The radial heater 5 generates heat when a direct current is applied to the nichrome wire. The induction heating coils 3 and 4 are each composed of a concentric outer coil 16 and an inner coil 17 that are arranged at intervals.

  In addition, three temperature detectors 18 to 20 are disposed on the lower surface of the top plate 7 at positions above the induction heating coils 3 and 4, respectively. One temperature detection unit 18 (corresponding to the first temperature detection unit) among the temperature detection units 18 to 20 is located at the center of the internal coil 17, and the remaining two temperature detection units 19 and 20 ( (Corresponding to the second temperature detection unit) is located between the external coil 16 and the internal coil 17.

  Each of the temperature detectors 18 to 20 is composed of, for example, a ceramic case mainly composed of aluminum nitride and a temperature detection element (none of which is shown) accommodated in the case. The upper surface of the case is in contact with the lower surface of the top plate 7, and the temperature of the pan placed on the induction heating units 8 and 9 is efficiently transmitted through the top plate 7. Moreover, the temperature detection element is arrange | positioned in the said case so that it may closely_contact | adhere to the inner surface of the said case. The lead wire 24 of the temperature detecting element is drawn out to a lower portion of the support base 15 through a hole 15a formed in the support base 15, and is connected to a wiring board (not shown).

A cooling fan device 25 is disposed on the right side of the rear portion of the housing portion 6a. The cooling fan device 25 is connected to a duct 26 disposed below the induction heating coils 3 and 4 for supplying air to the induction heating coils 3 and 4.
On the other hand, the lower unit 1b includes a roaster 28 and an operation panel 29 provided on the right part of the front door 28a of the roaster 28. The roaster 28 uses a sheathed heater (not shown) as a heat source. The operation panel 29 includes a power switch 30, induction heating coils 3 and 4, a radiant heater 5, an operation unit 31 for turning on / off a sheath heater of the roaster 28, and adjusting an output, a setting state, and the like. A display unit 32 for displaying is provided.

  FIG. 3 is a diagram showing a part related to one (left side) induction heating coil 3 in the electrical configuration of the induction cooking device according to the present embodiment. In FIG. 3, a control device 35 as a control means is configured mainly with a microcomputer, and supplies a high-frequency current to the induction heating coil 3 through an inverter circuit 36. The inverter circuit 36 is connected to a DC output terminal of a rectifier circuit 37 formed of a diode bridge. The DC output terminal of the rectifier circuit 37 is connected to both ends of a smoothing capacitor 39 via a reactor 38.

  The AC input terminal of the rectifier circuit 37 is connected to a commercial power source 40. A current transformer 41 is inserted on the AC input side of the rectifier circuit 37, and a secondary output voltage of the current transformer 41 is supplied to the control device 35 via a current detector 42. . The voltage between the AC input terminals of the rectifier circuit 37 is supplied to the control device 35 via the voltage detector 43. On the other hand, a current transformer 44 is inserted on the output side of the inverter circuit 36. The secondary output voltage of the current transformer 44 is given to the control device 35 via the inverter current detection unit 45.

  Then, the control device 35 includes the current value detected by the current detection unit 42, the voltage value detected by the voltage detection unit 43, the inverter current value detected by the inverter current detection unit 45, and the operation unit 31. The display unit 32 and the inverter circuit 36 are controlled based on the operation signal and the detection signals from the temperature detection units 18 to 20. Thereby, the inverter circuit 36 supplies a high frequency current to the induction heating coil 3.

  At this time, the control device 35 detects the heat generation amount of the temperature detection units 18 to 20 based on the inverter current value detected by the inverter current detection unit 45, and the heat generation amount and temperature detection unit of the temperature detection units 18 to 20 The temperature of the pan P is detected from the detected temperature of 18-20. Accordingly, the controller 35 and the inverter current detector 45 constitute a heat generation amount detector. The induction heating coil 3 (4), the control device 35, and the inverter circuit 36 constitute an induction heating means.

  Here, the relationship between the temperature detected by the temperature detectors 18 to 20 and the temperature of the cooking container will be described. FIG. 4 shows the relationship between the distance from the center of the induction heating coil 3 and the heat generation temperature of the temperature detectors 18 to 20. At the center of the induction heating coil 3, the magnetic flux generated by the current flowing through the external coil 16 and the internal coil 17 is concentrated, so that the magnetic flux density is high. Accordingly, the case of the temperature detection unit 18 and the temperature detection element are induction heated by the current flowing through the induction heating coil 3. On the other hand, since the magnetic flux generated by the external coil 16 and the internal coil 17 is opposite between the external coil 16 and the internal coil 17, the magnetic flux is canceled out. For this reason, the temperature detectors 19 and 20 disposed between the external coil 16 and the internal coil 17 are hardly induction-heated. Therefore, as shown in FIG. 4, the heat generation temperature of the temperature detection unit 18 is higher than the heat generation temperatures of the temperature detection units 19 and 20. The same applies to the induction heating coil 4.

  Further, as the inverter current supplied to the induction heating coil 3 increases, the induction current flowing through the temperature detection units 18 to 20 increases, so the amount of heat generated by the temperature detection unit 18 increases. FIG. 5 shows the relationship between the self-heating temperature of the temperature detector 18 and the inverter current detected by the inverter current detector 45. As shown in FIG. 5, the heat generation temperature of the temperature detector 18 is proportional to the inverter current.

  Therefore, the control device 35 calculates the heat generation temperature of each of the temperature detection units 18 to 20 based on the detection value of the inverter current detection unit 45, and performs correction to subtract the heat generation amount from the detection temperature of the temperature detection unit 18 to 20, respectively. By doing so, the temperature of the pan P is detected. With such a configuration, the control device 35 can detect the true temperature of the pan P placed on the induction heating units 8 and 9. In particular, since the control device 35 corrects the detected temperature for each of the temperature detectors 18 to 20, the detection accuracy of the pan P is improved.

  In addition, the control device 35 compares the detected temperatures after correction of the temperature detection units 18 to 20 after a predetermined time has elapsed from the start of heating by the induction heating coils 3 and 4. And when the detection temperature after correction | amendment of the said temperature detection parts 18-20 is equal, the radius dimension of the bottom face of the pan P is the distance from the temperature detection part 18 to the temperature detection part 19 (20), in other words, the inside of the external coil 16 It is judged that it is larger than the radial dimension of the peripheral part. Further, when the detected temperature after correction of the temperature detection unit 18 is higher than the detection temperature after correction of the temperature detection units 19 and 20, the radial dimension of the bottom surface of the pan P is larger than the radial dimension of the inner peripheral part of the external coil 16. Judge that it is small.

  When the radius dimension of the bottom surface of the pan P is smaller than the radial dimension of the inner peripheral portion of the external coil 16, the bottom surface of the pan P does not exist on the temperature detection units 19, 20, so The induction heating coils 3 and 4 are driven based only on the output. Moreover, since the used pan P is small, the control device 35 limits the maximum output of the induction heating coils 3 and 4. With such a configuration, the temperature of the pan can be accurately detected even when a small pan is used. Moreover, it can suppress that the temperature of the said pan rises excessively. Moreover, erroneous determination can be prevented by the configuration for determining the size of the pan based on the corrected temperature detected by the temperature detectors 18 to 20.

The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible.
The heat generation temperature of the temperature detectors 18 to 20 includes the current (inverter current) supplied from the inverter circuit 36 to the induction heating coils 3 and 4, the voltage supplied from the inverter circuit 36 to the induction heating coils 3 and 4, and the inverter It can be calculated based on the input current and input voltage of the circuit 36. In this case, the input current of the inverter circuit 36 corresponds to the detection current of the current detection unit 42. Further, the input power of the inverter circuit 36 can be detected based on the detection values of the current detection unit 42 and the voltage detection unit 43. The relationship between the heat generation temperature of the temperature detection unit 18 and the input current of the inverter circuit 36 is shown in FIG. Thus, the heat generation temperature of the temperature detector 18 and the input current of the inverter circuit 36 are proportional. Although not shown, the input voltage of the inverter circuit 36, the supply voltage from the inverter circuit 36 to the induction heating coils 3 and 4, and the heat generation temperature of the temperature detector 18 are also proportional to each other.

Furthermore, in the structure which sets the electric power of the induction heating coils 3 and 4 in the operation part 31, and drives the induction heating coils 3 and 4 based on the electric power setting value, the temperature detection parts 18-20 of the temperature detection parts 18-20 are based on the electric power setting value. The exothermic temperature may be calculated. That is, as shown in FIG. 7, the power setting value and the heat generation temperature of the temperature detector 18 are proportional.
Moreover, in the structure which sets the temperature of a cooking container by operating the operation part 31, and controls an induction heating means so that the temperature of a cooking container is maintained at preset temperature, according to the emitted-heat amount of a temperature detection part. The set temperature may be corrected. In this case, the operation unit functions as temperature setting means. That is, correction is performed to increase the set temperature by the amount of heat generated by the temperature detection unit. With such a configuration, it is possible to suppress the influence of induction heating of the temperature detection unit by the induction heating coil.

The induction heating coil may be configured not to be divided into an internal coil and an external coil, that is, configured by continuously winding a coil wire.
The number of temperature detection units is not limited to three, but may be one or two, or four or more. When providing one temperature detection part, it is desirable to arrange | position in the center part of an induction heating coil.

The top view which shows one Example of this invention Front view showing a part of the induction heating cooker The block diagram which shows the electric constitution of the part regarding one induction heating coil of the induction heating cooking appliances The figure which shows the relationship between the distance from the center of an induction heating coil, and the emitted-heat amount of a temperature detection part A diagram showing the relationship between the heat generation temperature of the temperature detector and the inverter current FIG. 8 is a diagram for explaining a modification of the present invention, and is a diagram illustrating a relationship between a heat generation temperature of a temperature detection unit and an input current of an inverter circuit FIG. 10 is a diagram for explaining another modification of the present invention, and shows a relationship between the heat generation temperature of the temperature detection unit and the power setting value.

Explanation of symbols

In the drawing, 1 is a heating cooker body, 3 and 4 are induction heating coils, 7 is a top plate, 18 is a temperature detector (first temperature detector), and 19 and 20 are temperature detectors (second temperature detector). Part), 35 is a control device (control means, heat generation amount detection means, induction heating means), 36 is an inverter circuit, 45 is an inverter current detection portion (heat generation amount detection means), and P is a pan (cooking vessel).

Claims (7)

An induction heating means having an induction heating coil and an inverter circuit for supplying a high frequency current to the induction heating coil;
A top plate provided above the induction heating coil and on which a cooking vessel is placed;
A temperature detection unit disposed between the top plate and the induction heating coil;
A calorific value detection means for detecting a calorific value of the temperature detection unit based on at least one of the input current and input power of the inverter circuit, and the current and power supplied from the inverter circuit to the induction heating coil;
An induction heating cooker comprising: control means for controlling the induction heating means based on the output of the temperature detection unit and the output of the calorific value detection means. Temperature setting means for setting the temperature of the cooking container,
2. The induction heating cooker according to claim 1, wherein the control means controls the induction heating means based on the output of the heat generation amount detection means, the output of the temperature detection unit, and the temperature set by the temperature setting means.   The induction heating cooker according to claim 1 or 2, wherein the control means detects the temperature of the cooking container based on the output of the temperature detection unit and the output of the calorific value detection means.   The induction heating cooker according to claim 2, wherein the control means corrects the set temperature by the temperature setting means based on the output of the calorific value detection means. The temperature detector is composed of a plurality of temperature detectors arranged at different positions between the top plate and the induction heating coil,
The induction heating cooker according to claim 1 or 2, wherein the control unit corrects the detected temperatures of the plurality of temperature detection units based on the output of the calorific value detection unit.   The induction heating cooker according to claim 5, wherein one of the plurality of temperature detection units is disposed at a central portion of the induction heating coil. The plurality of temperature detection units includes a first temperature detection unit disposed at the center of the induction heating coil and a second temperature detection unit disposed radially away from the center of the induction heating coil. When the detected temperatures of the first and second temperature detection units are substantially the same, the radius of the bottom surface of the cooking container is the length between the first temperature detection unit and the second temperature detection unit. 6. The induction heating cooker according to claim 5, further comprising container radius determining means for determining that the size is equal to or larger than the size.

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