JP4346511B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker provided with temperature detection means for detecting the temperature of a cooking container.

  An induction heating cooker called 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 temperature detection element disposed below the top plate, and the drive of the inverter device is controlled based on the detection result. Yes.

In this case, if the bottom surface of the cooking container and the temperature detection element are separated due to deformation of the cooking container, a temperature lower than the actual temperature of the cooking container is detected. Therefore, an induction heating cooker that provides a plurality of temperature detection elements and controls the induction heating coil with the detection temperature of the detection element closest to the cooking container, that is, the highest detection temperature as the temperature of the cooking container is considered. It has been.
JP 2002-102062 A

  By the way, when the temperature of the object to be heated falls suddenly, such as when a low temperature ingredient is put in boiling water, or when a frozen croquette is put in oil that has risen to an appropriate temperature, etc. Usually, control for increasing the output of the induction heating coil is performed to restore the temperature of the object to be heated. Therefore, in such a case, the temperature of the object to be heated can be quickly returned by detecting that the temperature has decreased as soon as possible.

  However, when foods having a low temperature, frozen croquettes, or the like are concentrated and put into a specific part, the timing at which the detected temperature begins to drop differs depending on the part where the temperature detecting element is arranged. That is, the detection temperature of the temperature detection element arranged at a site away from the charging site such as ingredients starts to fall later than the detection temperature of the temperature detection element positioned near the charging site. Accordingly, if it is determined that the temperature has decreased based only on the highest temperature among the detected temperatures, detection of the temperature decrease may be delayed.

  This invention is made | formed in view of the said situation, The objective provides the induction heating cooking appliance which can detect the temperature of a to-be-heated object correctly, and can detect the temperature change of a to-be-heated object rapidly. That is.

An induction heating cooker according to the present invention includes an induction heating unit having an induction heating coil, a top plate provided above the induction heating coil and on which an object to be heated is placed, the top plate, and the induction heating coil. A plurality of temperature detection units that are arranged at different positions to detect the temperature of the object to be heated, and a maximum temperature determination unit that determines the highest temperature among the temperatures detected by the plurality of temperature detection units, wherein comprising a temperature change determining means for determining a change amount of at least one temperature of the plurality of temperatures detected by the temperature detector, and control means for controlling the pre-Symbol induction heating means, the control means, frying Is performed, the target temperature T0 is set, and the temperature determined by the maximum temperature determination means is set as the determination temperature Td so that the determination temperature Td is maintained at the target temperature T0. The induction heating unit is controlled, and when the amount of change in temperature determined by the temperature change determination unit becomes equal to or greater than a predetermined value, a target temperature T0 ′ that is equal to or lower than the target temperature T0 is set, and the predetermined value The temperature detected by the temperature detector showing the above change is set as a determination temperature Td ′, the induction heating means is controlled so that the determination temperature Td ′ reaches the target temperature T0 ′, and the determination temperature Td ′ is wherein when reaching the target temperature T0 ', the determination temperature Td is characterized that you control the induction heating means so as to maintain the target temperature T0 again.

  The present invention combines the control of the induction heating unit based on the highest value among the detection temperatures of the plurality of temperature detection units and the control of the induction heating unit based on the amount of change in the detection temperature of the plurality of temperature detection units. Since the rapid temperature change of the object to be heated can be detected quickly while detecting the exact temperature of the object to be heated, the temperature of the object to be heated can be accurately controlled.

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 FIGS. 1 to 6.
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 consists of and.

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 heating object P (see FIG. 3) such as a pan or a frying pan is placed on the heating units 8 to 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 pan having a large diameter dimension such as a wok is used as the heating unit 8. , 9 so that 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. Further, 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 is composed of a thin rectangular box-shaped accommodating portion 6a for accommodating the induction heating coils 3 and 4 and the radiant heater 5, and a flange 6b projecting to the upper left and right. 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 placed 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 an external heating coil 16 and an internal heating coil 17 disposed on the inner peripheral portion of the external heating coil 16. The heating coils 16 and 17 are spaced apart so that their centers coincide. The heating coils 16 and 17 are composed of a single continuous wire. For example, the external heating coil 16 is wound by winding the wire 9 times, and the internal heating coil 17 is wound by winding 11 times. It is configured.

  Three temperature detectors 18 to 20 are disposed on the lower surface of the top plate 7 above the internal heating coils 17. One of the temperature detectors 18 to 20 is located at the center of the internal heating coil 17, and the remaining two temperature detectors 19 and 20 are the external heating coil 16 and the internal heating coil 17. Is located between. The temperature detection unit 18 is composed of a temperature detection element (none of which is shown) housed in a ceramic case mainly composed of aluminum nitride having thermal conductivity. The temperature detectors 18 to 20 are arranged such that the upper surface of the case is in contact with the lower surface of the top plate. 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 in the housing portion 6a. A duct 26 for guiding the wind generated by the cooling fan device 25 to the lower part of the induction heating coils 3 and 4 is disposed in the accommodating portion 6a.
On the other hand, the lower unit 1b includes a roaster 28 and an operation panel 29 provided on the right side of the front door 28a of the roaster 28. The roaster 28 uses a sheathed heater (not shown) as a heat source. On the operation panel 29, a power switch 30, the induction heating coils 3 and 4, the radiant heater 5, an operation dial 31 for turning on / off the sheath heater of the roaster 21 and adjusting the output, and a cooking menu are set. There are provided a menu setting key 32 and a display 33 for displaying a heating state and the like.

  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 an output signal of a temperature detection element of the operation unit 34 and the temperature detection units 18 to 20 is input thereto. The operation unit 34 outputs a signal corresponding to the operation of the operation dial 31 and the menu setting key 32. The control device 35 controls the display unit 33 based on the output signals of the operation unit 34 and the temperature detection units 18 to 20, or controls the inverter 36 to supply a high-frequency current to the induction heating coil 3.

  Therefore, the control device 35 and the induction heating coil 3 (and 4) function as induction heating means. Further, as will be described later, the control device 35 functions as a maximum temperature determination unit and a temperature change amount determination unit. Although not shown in detail, the inverter 36 is composed of a power element connected in parallel, for example, a half bridge inverter provided with an IGBT.

  Next, the operation of the above configuration will be described with reference to the flowchart of FIG. Here, a case where fried food such as tempura is performed will be described. The user places a pot as an object to be heated on one of the induction heating sections 8 and 9 of the top plate 7, for example, the left induction heating section 8. Thereafter, the menu setting key 32 on the operation panel 29 is operated to set the “fried food cooking menu”, and then the operation dial 31 is operated to start energization of the induction heating coil 3. Thereby, the control apparatus 35 performs fried food cooking according to the flowchart of FIG. That is, the target temperature T0 is set (step S1), and the induction heating coil 3 is driven according to a preset control program (step S2). As a result, the pot is induction heated and the temperature of the oil stored in the pot rises.

  The change in the temperature of the oil can be confirmed on the output display section 11 provided on the top plate 7. Further, when energization to the induction heating coil 3 is started, the cooling fan device 25 is driven. As a result, air flows into the case 6 through the duct 26 by the air blowing action of the cooling fan device 25, and after flowing through the case 6, is discharged from the exhaust port 7b. As a result, it is possible to prevent the induction heating coil 3 being energized from rising in temperature and the temperature detection units 18 to 20 and the like from being heated by the induction heating coil 3 to increase in temperature.

  Subsequently, the control device 35 reads the outputs of the three temperature detection elements (step S3), and sets the highest value among the detection temperatures Th1 to Th3 as the determination temperature Td (step S4). Then, the determination temperature Td is compared with the target temperature T0 (step 5). If the determination temperature Td is lower than the target temperature T0 (NO), the process returns to step S3, and the determination temperature Td reaches the target temperature T0. If yes (YES), the process proceeds to step S6. Note that the control device 35 gradually decreases the input power of the induction heating coil 3 based on the temperature Td until the determination temperature Td reaches the target temperature T0.

  On the other hand, in step 6, the control device 35 adjusts the input power to the induction heating coil 3 so that the pan temperature is maintained at the target temperature T0. Also in this case, the control device 35 determines the pan temperature based on the highest temperature among the detected temperatures Th1 to Th3 of the three temperature detecting elements. Further, the control device 35 reads the outputs of the three temperature detection elements (step S7), and calculates the amount of change in each of the detected temperatures Th1 to Th3. Here, the detected temperature of each temperature detection element when the pan temperature is maintained at the target temperature T0 is defined as a reference temperature, and the difference from the reference temperature is defined as the amount of change in each detected temperature Th1 to Th3. Then, it is determined whether or not the amount of change in each of the detected temperatures Th1 to Th3 exceeds a predetermined value (for example, 3 deg) (step S8), and if the amount of change in any detected temperature is equal to or less than the predetermined value (NO), Return to step S6.

  Further, if there is a change amount of each detected temperature Th1 to Th3 that exceeds a predetermined value (YES), the target temperature is changed to T0 ′ (T0 ′ ≦ T0) (step S9). Then, the detected temperature of the temperature detecting element whose change amount exceeds the predetermined value is set to the determination temperature Td ′, and the input power of the induction heating coil 3 is increased (step S10). The control for driving the induction heating coil 3 by increasing the input power is performed until the determination temperature Td ′ reaches the target temperature T0 ′ (step S11). When determination temperature Td ′ reaches target temperature T0 ′ (YES in step S11), the target temperature is returned to T0 (step S12), and then the process returns to step S3.

  FIG. 5 is a diagram showing the relationship between the oil temperature during frying and the input power (high frequency power) of the induction heating coil. In FIG. 5, the horizontal axis indicates the elapsed time since the start of energization of the induction heating coil, and the vertical axis indicates the oil temperature (° C.) and the input power (kW). A solid line A indicates the oil temperature, and a solid line B indicates a change in the input power. As shown in FIG. 5, the control device 35 adjusts the input power of the induction heating coil so that the oil temperature gradually increases and reaches the target temperature (about 192 ° C.).

In FIG. 5, an arrow indicates a timing at which, for example, a frozen croquette is put into oil. In this way, when the ingredients are introduced while the oil temperature is maintained at the target temperature, the oil temperature rapidly decreases. At this time, the timing at which the detected temperatures of the three temperature detectors 18 to 20 start to drop differs depending on the position at which the ingredients are introduced.
For example, FIG. 6 shows a change pattern of the detected temperatures of the three temperature detectors 18 to 20 when the ingredients are concentrated and put on the near side of the pan. FIG. 6 shows the relationship between the oil temperature before and after the ingredients are introduced and the temperature detected by the three temperature detectors 18 to 20, and the solid line A is the pan temperature, the two-dot chain line B1, the one-dot chain line B2, A broken line B3 indicates the detected temperatures of the center, front, and rear temperature detectors 18, 19, and 20, respectively. As shown in FIG. 6, the timing at which the detected temperature of the temperature detecting unit 19 closest to the portion where the ingredient is introduced starts to decrease compared to the other temperature detecting units 18 and 20. Therefore, in this case, the amount of change in the temperature detected by the temperature detecting unit 19 reaches a predetermined value (3 deg) about 30 seconds after the ingredients are introduced, and based on this, the controller 35 lowers the pan temperature, i.e., the ingredients. It is detected that the material has been introduced (step S8 in FIG. 4).

  Thus, according to the present embodiment, the temperature detectors 18 to 20 are arranged between the central portion of the internal heating coil 17 and between the external heating coil 16 and the internal heating coil 17 until the pan temperature reaches the target temperature. During this period and while maintaining the pan temperature at the target temperature, the highest temperature among the detected temperatures of the temperature detectors 18 to 20 was set as the pan temperature. Therefore, even when the bottom surface of the pan is deformed or the pan is shifted from the induction heating units 8 and 9, the pan temperature can be accurately detected.

Further, while the pan temperature is maintained at the target temperature, the amount of change per unit time of the temperature detected by the temperature detectors 18 to 20 is detected, and the induction heating coil is based on the amount of change exceeding a predetermined value. The input power is configured to increase. Therefore, it is possible to quickly detect that the temperature of the oil has fallen due to the ingredients being introduced into the oil, and to return to the target temperature.
As described above, the control of the induction heating coils 3 and 4 based on the highest temperature among the detected temperatures and the control of the induction heating coils 3 and 4 based on the detected temperature having the largest amount of change per unit time are combined. By this, since the change in the pan temperature can be detected quickly while accurately detecting the pan temperature, the cooking of the object to be heated by the induction heating coils 3 and 4 can be performed satisfactorily.

  Furthermore, based on the fact that the amount of change per unit time among the detected temperatures of the temperature detectors 18 to 20 exceeds a predetermined value, the heated object in the cooking container is boiled and burnt, or in an empty cooking state It is also possible to detect the presence of

Furthermore, the present invention is not limited to the embodiment described above and shown in the drawings. For example, the following modifications are possible .

The induction heating coil is not limited to the one divided into the external heating coil and the internal heating coil, but may be one wound continuously.
The number of temperature detection units may be two or four or more.

The top view of the induction heating cooking appliance which concerns on one Example of this invention Front view of induction cooker with part cut away The block diagram which shows the electrical structure of the part regarding one induction heating coil among induction heating cooking appliances. Flow chart showing temperature detection unit selection processing The figure which shows the relationship between the oil temperature at the time of deep-fried food cooking, and the input current of an induction heating coil The figure which shows the relationship between the oil temperature before and after material is thrown into the oil of the state maintained at target temperature, and the detection temperature by three temperature detection parts.

Explanation of symbols

  In the drawings, 1 is a heating cooker body, 3 and 4 are induction heating coils, 7 is a top plate, 18 to 20 are temperature detection units, 32 is a cooking menu setting key, and 35 is a control device (control means, maximum temperature determination means). , Temperature change determination means, induction heating means).

Claims (2)

Induction heating means having an induction heating coil;
A top plate provided above the induction heating coil and on which an object to be heated is placed;
A plurality of temperature detectors arranged at different positions between the top plate and the induction heating coil to detect the temperature of the object to be heated;
Maximum temperature determination means for determining the highest temperature among the temperatures detected by the plurality of temperature detection units;
Temperature change determination means for determining a change amount of at least one of the temperatures detected by the plurality of temperature detection units;
And control means for controlling the pre-Symbol induction heating means,
When the fried food cooking is performed, the control unit sets a target temperature T0, and the determination temperature Td is maintained at the target temperature T0 with the temperature determined by the maximum temperature determination unit as the determination temperature Td. Controlling the induction heating means, and setting a target temperature T0 ′ that is equal to or lower than the target temperature T0 when the amount of change in temperature determined by the temperature change determination means is equal to or greater than a predetermined value, The temperature detected by the temperature detector showing a change of a predetermined value or more is set as a determination temperature Td ′, the induction heating means is controlled so that the determination temperature Td ′ reaches the target temperature T0 ′, and the determination temperature Td If the 'is the target temperature T0' reaches the induction heating tone the judgment temperature Td is characterized that you control the induction heating means so as to maintain the target temperature T0 again Vessel. The induction heating coil is composed of an external heating coil and an internal heating coil that are spaced apart so that their centers coincide.
The induction heating cooker according to claim 1, wherein the plurality of temperature detection means are located between a central portion of the internal coil and between the internal coil and the external coil .

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