JP2011150796A - Induction heating cooker and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe induction heating cooker which is excellent in cooking performance and can keep high heating power with an adequate temperature while preventing oil firing when a user cooks stir-fry or the like with a small amount of oil with a frying pan after preheating completion. <P>SOLUTION: The induction heating cooker includes a temperature difference calculation means 15 computing a temperature difference between a target temperature updated each predetermined time and a temperature detected with an infrared sensor, a temperature gradient calculation means 14 computing an amount of time variation of detected values of the temperature detected by the infrared sensor 4, and a heating power determination means 13 determining the heating power by using the computed values of the temperature difference calculation means and the temperature gradient calculation means as the input values. During the heating mode after the preheating completion, the heating output is configured to be updated by the heating power determination means so that the heating power output depending on the set heating power output is set as the maximum. With this, high heating power can be retained while preventing firing with a small amount of oil. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating cooker that heats an object to be heated such as a cooking container.

  In recent years, induction heating cookers that induction-heat cooking containers such as pans and frying pans with a heating coil have been widely used in general households and commercial kitchens. Some recent induction heating cookers are equipped with a preheating mode that automatically heats the cooking container and detects when it reaches the proper temperature while detecting the pan bottom temperature of the cooking container with an infrared sensor. There is one that is convenient when preheating a frying pan during cooking or the like (see, for example, Patent Document 1).

JP 2009-238686 A

  However, in the conventional induction heating cooker, when the heating is continued after the preheating is completed in the preheating mode, the heating output is reduced or the heating is stopped when the detection temperature of the infrared sensor reaches the first predetermined temperature, and the detection temperature is stopped. When the temperature falls to a second predetermined temperature lower than the first predetermined temperature, a control is adopted in which the heating output is increased or the heating is restarted. It had the problem of falling too much.

  The present invention solves the above-mentioned conventional problems, and prevents the ignition of oil when a user continues cooking after completion of preheating, specifically when cooking a fried food with a small amount of oil using a frying pan. In addition, an object of the present invention is to provide an induction heating cooker that is capable of maintaining an appropriate temperature while maintaining a high heating power, and that is safe and excellent in cooking performance.

  In order to solve the above-described conventional problems, an induction heating cooker according to the present invention includes a top plate formed of a material that transmits infrared rays, and a cooking that is provided below the top plate and placed on the top plate. A heating coil for induction heating the container, an inverter circuit for supplying a high frequency current to the heating coil, an operation unit for setting an operation mode of the inverter circuit and the heating output, and radiated from the bottom surface of the cooking container, Infrared sensor that detects infrared light transmitted through the top plate, a heating control unit that controls the heating output based on the output of the infrared sensor, a notification unit, and a target temperature that is updated every first predetermined time A first temperature difference calculating means for calculating a difference between the temperature detected by the infrared sensor and the temperature detected by the infrared sensor; First temperature gradient calculating means for calculating the amount; first thermal power determining means for determining the heating output by inputting the calculated values of the first temperature difference calculating means and the first temperature gradient calculating means; And when the increase amount of the output value of the infrared sensor with respect to a predetermined value exceeds a predetermined increase amount after starting heating in the first heating mode, the operation unit has a second heating output lower than the first heating output. When the heating output is changed to the third heating output through the operation unit by the user during the standby mode, the preheating mode for changing to the heating mode for heating with the third heating output is selected. And a preheating mode selection unit for updating the heating output by the first heating power determination means while maximizing the third heating output during the heating mode.

As a result, when the user continues cooking after completion of preheating, the pan bottom temperature is directly detected by the infrared sensor to prevent overheating, and even if a small amount of oil is in the cooking container, ignition is prevented. Since the high heating power can be maintained by frequently adjusting the heating output from the temperature difference from the target temperature and the gradient of the temperature change, a product that is safe and has good cooking performance can be provided to the user.

  The induction heating cooker of the present invention suppresses an excessive rise in the pan bottom temperature and prevents ignition of a small amount of oil, and can maintain a high heating power by frequently adjusting the heating output.

The block diagram which shows the structure of the induction heating cooking appliance in Embodiment 1 of this invention. The circuit diagram of the infrared sensor of the induction heating cooking appliance in Embodiment 1 of this invention The characteristic figure of the infrared sensor of the induction heating cooking appliance in Embodiment 1 of this invention The block diagram which shows the structure which added the thermistor of the induction heating cooking appliance in Embodiment 1 of this invention. The flowchart which shows operation | movement of the preheating mode of the induction heating cooking appliance in Embodiment 1 of this invention.

  A first invention includes a top plate formed of a material that transmits infrared rays, a heating coil that is provided below the top plate and that induction-heats a cooking vessel placed on the top plate, and the heating coil An inverter circuit for supplying a high-frequency current; an operation unit for setting an operation mode of the inverter circuit and the heating output; an infrared sensor for detecting infrared rays radiated from the bottom surface of the cooking vessel and transmitted through the top plate; Based on the output of the infrared sensor, a heating control unit for controlling the heating output, a notification unit, and a difference between a target temperature updated every first predetermined time and a temperature detected by the infrared sensor are calculated. First temperature difference calculating means, first temperature gradient calculating means for calculating a time change amount of a detected value of the temperature detected by the infrared sensor, 1 temperature difference calculating means and a first heating power determining means for inputting the calculated value of the first temperature gradient calculating means and determining the heating output, and the operation section is heated in the first heating mode. When the increase amount of the output value of the infrared sensor with respect to the predetermined value exceeds a predetermined increase amount after the start, the mode shifts to a standby mode in which heating is performed with a second heating output lower than the first heating output and is used during the standby mode When the heating output is changed to the third heating output by the operator through the operation unit, the heating unit has a preheating mode selection unit for selecting a preheating mode for shifting to the heating mode for heating with the third heating output. Is that the third heating output is maximized and the heating output is updated by the first heating power determining means. As a result, when the user continues cooking after completion of preheating, the pan bottom temperature is directly detected by the infrared sensor to prevent overheating, and a small amount of oil is prevented from igniting. Since the high heating power can be maintained by frequently adjusting the heating output from the gradient of the change, it is possible to provide a safe product with good cooking performance for the user.

  In the second invention, in particular, the predetermined value of the first invention is an output value of the infrared sensor before and after the start of heating in the first heating mode or an output value in the absence of light stored at the time of factory shipment. It is a thing. As a result, the infrared sensor can detect an accurate temperature, and enables safer control.

  According to a third aspect of the invention, in particular, the infrared sensor of the first or second aspect of the invention comprises an InGaAs photodiode. Thereby, since the range of the temperature which can be detected becomes wide, fine temperature control can be made possible in a wide temperature range.

In particular, the fourth invention includes an input power integrating means for integrating the input power in any one of the first to third inventions, and the integrated value of the input power integrating means has a predetermined integrated value during the heating mode. If it exceeds, the update of the heating output by the first thermal power determining means is stopped, and heating is performed with the selected heating output. As a result, after the integrated value of the input power integrating means exceeds a predetermined integrated value that reaches a thick frying pan and does not reach a thin frying pan within a certain period of time, heating by the first thermal power determining means By stopping the update of the output so that the heating output according to the heating output setting is always input, it is unnecessary even if the temperature rise of the cooking container slows down when the food is put into the cooking container. It is possible to prevent the heating output from being lowered, and there is no fear of ignition if the cooked material is thrown in, and high-heat cooking can be realized.

  According to a fifth aspect of the invention, in particular, in the fourth aspect of the invention, the predetermined integrated value is changed according to the setting of the heating output. Thus, if the predetermined integrated value is the same for any heating output setting, for example, the lower the heating output setting, the longer the time until the predetermined integrated value is reached, and the heating output as the heating output setting is always set. Input food detection is delayed. Therefore, by setting the predetermined integrated value to a smaller value as the heating output setting is lower, after the predetermined integrated value is exceeded, the update of the heating output by the first heating power determining means is stopped and the heating output setting is followed. The cooking power is always input so that when the food is put into the cooking container, the cooking power is prevented from being unnecessarily lowered even if the temperature rises in the cooking container. It is possible to detect the input of an object quickly and to input the heating output according to the heating output setting.

  In a sixth aspect of the present invention, in particular, in the heating mode of any one of the first to fifth aspects, when the heating output setting is equal to or higher than a predetermined heating output, the heating output is updated by the first heating power determining means It is a configuration. Thereby, ignition can be reliably prevented only when the risk of ignition of a small amount of oil is high with high heating power, and when the heating output is low, heating can be performed with the heating output as set by the heating output.

  In a seventh aspect of the invention, in particular, in any one of the first to sixth aspects of the invention, a thermistor disposed below the top plate and detecting the temperature of the bottom surface of the cooking vessel via the top plate; A second temperature difference calculating means for calculating a difference between a target temperature updated every predetermined time and a temperature detected by the thermistor; and a second temperature calculating amount of a detected value of the temperature detected by the thermistor. A temperature gradient calculating means; and a second heating power determining means for determining a heating output with the calculated values of the second temperature difference calculating means and the second temperature gradient calculating means as inputs, and during the heating mode, The first thermal power determination means and the second thermal power determination means operate in parallel and adopt a configuration in which the lower heating output is adopted to update the heating output. Thereby, even if the infrared sensor fails, the temperature can be controlled by the thermistor to prevent oil ignition.

  In particular, the eighth invention provides a program for causing a computer to execute at least one of the induction heating cookers according to any one of the first to seventh inventions. Since it is a program, at least a part of the induction heating cooker of the present invention can be easily realized by cooperating hardware resources such as an electric / information device, a computer, and a server. In addition, the program can be distributed / updated and installed easily by recording on a recording medium or distributing the program using a communication line.

  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)
FIG. 1 is a block diagram showing the configuration of the induction heating cooker according to the first embodiment of the present invention. In FIG. 1, a top plate 1 is provided on the upper surface of the apparatus, and a cooking container 2 is placed thereon.

  A heating coil 3 for inductively heating the cooking vessel 2 on the top plate 1 by generating a high-frequency magnetic field is provided below the top plate 1, and infrared rays radiated from the cooking vessel 2 are transmitted below the heating coil 3. An infrared sensor 4 that receives light and outputs an output corresponding to the temperature is provided.

  The commercial power supply 5 is input to the rectifying / smoothing unit 6. The rectifying / smoothing unit 6 is connected between a full-wave rectifier constituted by a bridge diode and a low-pass filter constituted by a choke coil and a smoothing capacitor between its DC output terminals.

  An inverter circuit 7 is connected to the output of the rectifying / smoothing unit 6, and the heating coil 3 is connected to the inverter circuit 7. The inverter circuit 7 and the heating coil 3 constitute a high frequency inverter. The inverter circuit 7 is provided with a switching element 8.

  A diode 9 is connected to the switching element 8 in antiparallel. A resonance capacitor 10 is connected in parallel to the heating coil 3. The heating control unit 11 receives a signal from the operation unit 12, an input power value, and information from the infrared sensor 4, outputs a signal for driving the switching element 8, generates a high-frequency magnetic field in the heating coil 3, and causes the cooking container 2 to move. Heat.

  Furthermore, the first temperature difference calculating means 15 for calculating the difference between the target temperature updated every first predetermined time and the temperature detected by the infrared sensor 4, the time change of the detected value of the temperature detected by the infrared sensor 4 The first temperature gradient calculating means 14 for calculating the amount, the first thermal power determining means 13 for determining the heating output by inputting the calculated values of the first temperature difference calculating means and the first temperature gradient calculating means, It is comprised by the alerting | reporting part 16 which alert | reports completion.

  The operation unit 12 includes keys such as a heating start key 12a, a heating power up key 12b, a heating power down key 12c, a heating stop key 12d, and a preheating mode selection key 12e.

  FIG. 2 shows a circuit diagram of the infrared sensor 4 of the induction heating cooker according to the first embodiment of the present invention. In FIG. 2, the infrared sensor 4 includes a photodiode 21, an operational amplifier 22, and resistors 23 and 24.

  One ends of the resistors 23 and 24 are connected to the photodiode 21, and the other ends are connected to the output terminal and the inverting output terminal of the operational amplifier 22, respectively. A current flows when the photodiode 21 is irradiated with infrared rays having a wavelength of about 3 microns or less that are transmitted through the top plate 1. The higher the temperature of the irradiated infrared rays, the larger the magnitude and rate of increase of the flowing current. A light receiving element formed of InGaAs or the like.

  The current generated by the photodiode 21 is amplified by the operational amplifier 22 and output to the heating control unit 11 as an infrared detection signal 25 (corresponding to the voltage value V) indicating the temperature of the cooking vessel 2.

  The infrared sensor 4 receives infrared rays radiated from the cooking container 2 and therefore has better thermal response than a thermistor that detects the temperature via the top plate 1.

  FIG. 3 is a characteristic diagram of the infrared sensor of the induction heating cooker according to the first embodiment of the present invention, and shows the output characteristic of the infrared sensor 4.

In FIG. 3, the horizontal axis represents the bottom surface temperature of the cooking container 2 such as a cooking container, and the vertical axis represents the voltage value of the infrared detection signal 25 output from the infrared sensor 4. When an infrared ray having a wavelength of about 3 microns or less that is transmitted through the top plate 1 is irradiated, a current flows. As the temperature of the irradiated infrared ray increases, the magnitude and increase rate of the flowing current increase.

  For example, since it is a light receiving element formed of InGaAs or the like, for example, if 140 ° C. to 200 ° C. is defined as a low temperature region, 200 ° C. to 250 ° C. is defined as a medium temperature region, and 250 to 330 ° C. is defined as a high temperature region, As the temperature (detection value) increases, the amplification factor is switched (not shown), and the temperature region is switched from low temperature region to medium temperature region to high temperature region, thereby allowing the low temperature region, medium temperature region, and high temperature shown in FIG. Each infrared output Vo [V] can be obtained in the region.

  The heating control in the present embodiment is optimal for cooking when high heating power is required such as stir-fry and depending on the material and shape of the cooking container, which may affect overheating of the cooking container and oil ignition. Since the purpose is to heat with the heating output, if the bottom thickness of the cooking container is thin (for example, 1 mm or less) when the target temperature during heating is high, the heating output is corrected so as not to overheat. In a general cooking container (for example, a frying pan having a bottom thickness of 2.5 mm or more), a high heating power output may be obtained.

  Therefore, the infrared sensor 4 of the present embodiment outputs the infrared detection signal 25a when the bottom surface temperature of the cooking container 2 is about 140 to 200 ° C., and the infrared detection signal 25b when the bottom surface temperature is about 200 to 250 ° C. And the infrared detection signal 25c is output when the bottom surface temperature is about 250 to 330 ° C.

  The infrared sensor 4 does not output the infrared detection signal 25 when the bottom surface temperature of the cooking vessel 2 is less than about 140 ° C. In this case, “not outputting the infrared detection signal 25” means not only outputting the infrared detection signal 25 but also not substantially outputting it, that is, the heating control unit 11 changes the magnitude of the infrared detection signal 25. Based on outputting a weak signal that cannot substantially read the temperature change of the bottom surface of the cooking container 2.

  The output value of the infrared detection signal 25 increases exponentially when the temperature of the cooking vessel 2 reaches about 140 ° C. or higher.

  The infrared sensor is not limited to a photodiode, and may be an element that detects infrared rays, such as a thermopile.

  FIG. 4 is a block diagram showing a configuration in which the thermistor of the induction heating cooker in the first embodiment of the present invention is added. In FIG. 4, the same reference numerals as those in FIG.

  In FIG. 4, a thermistor 26 that is disposed under the top plate 1 and detects the temperature of the bottom surface of the cooking container via the top plate 1, a target temperature that is updated every second predetermined time, and the thermistor 26. A second temperature difference calculating means 20 for calculating a difference from the detected temperature; a second temperature gradient calculating means 19 for calculating a time change amount of a detected value of the temperature detected by the thermistor 26; and the second temperature difference calculating means 19 It has the 2nd thermal power determination means 18 which determines the heating output by using the calculated value of the temperature difference calculation means 20 and the said 2nd temperature gradient calculation means 19 as an input, and the 1st thermal power determination means 13 and the 1st thermal power determination means during heating mode. The two heating power determining means 18 operate in parallel and adopt a configuration in which the lower heating output is adopted to update the heating output. Thereby, even if the infrared sensor fails, the temperature can be controlled by the thermistor to prevent oil ignition.

In a heating mode in which heating is performed with a heating output changed by the user through a standby mode after completion of preheating, the heating output set by the user is maximized to the first heating output (heating output during preheating). Update the heating power while adopting a lower heating power.

  The thermistor (not shown) is provided on the lower side (heating coil 3 side) of the top plate so as to detect the temperature of the cooking container.

  Further, the input power detection means 17 of the induction heating cooker determines whether or not the integrated value of the input power has reached a predetermined integrated value, and stops the first thermal power determination means and the second thermal power determination means. It is said.

  The heating control means can be realized by using a microcomputer for the heating control unit.

About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.
FIG. 5 is a flowchart showing the operation of the preheating mode of the induction heating cooker in the first embodiment of the present invention.

  First, when the preheating mode selection key 12e of the operation unit 12 is operated, the preheating mode is executed. In FIG. 5, the preheating mode starts at STEP 101. Next, in STEP 102, it is determined whether or not the increase amount of the output value of the infrared sensor after starting the preheating mode has reached a predetermined increase amount.

  This predetermined value may be an output value of the infrared sensor before and after the start of heating in the preheating mode or an output value in the absence of light stored at the time of factory shipment. If it has reached, the process proceeds to STEP 103 to notify that the preheating is completed, and the process proceeds to a standby mode in which heating is performed with a heating output lower than the preheating mode.

  Next, in STEP 104, it is determined whether the thermal power up key or the thermal power down key has been pressed. When either key is pressed, the routine proceeds to STEP 105.

  In STEP 105, the mode is shifted to a heating mode in which heating is performed with the set heating output, and the first heating power determining means and the second heating power determining means using the temperature detected by the thermistor are operated, and the set heating output is maximized. The heating output is updated while adopting the lower heating output.

  Next, in STEP 106, it is determined whether or not the integrated value of the input power has reached a predetermined integrated value. When it reaches, it moves to STEP107.

  In STEP 107, the first thermal power determining means and the second thermal power determining means are stopped, and heating at the set heating output is started. Here, the predetermined integrated value of the input power at which the thermal power determining means stops may be a different value between the first thermal power determining means and the second thermal power determining means.

  As described above, in the present embodiment, when the user continues cooking after preheating is completed, the pan bottom temperature is directly detected by the infrared sensor to prevent overheating and to prevent ignition of a small amount of oil. Since the heating power can be maintained frequently by adjusting the heating output from the temperature difference from the target temperature and the gradient of the temperature change, an induction heating cooker that is safe for the user and good in cooking performance can be provided. .

  Further, even when the infrared sensor fails, the heating output can be controlled by the second heating power determining means using the temperature detected by the thermistor.

In addition, the lower the heating output setting, the longer the time until the predetermined integrated value is reached, and the slower the detection of the cooking input, but the predetermined integration of the input power at which the thermal power determining means stops according to the heating output setting. Changing the value, for example, by setting the predetermined integrated value to a smaller value as the heating output setting is lower, it is possible to detect the input of the food earlier and to input the heating output according to the heating output setting. it can.

  Further, in the heating mode, when the heating output setting is equal to or higher than the predetermined heating output, the heating power is updated by the first heating power determining means, so that there is a high risk of ignition of a small amount of oil with high heating power. Only reliably prevents ignition, and when the heating output is low, heating can be performed with the heating output as set by the heating output.

  The means described in this embodiment cooperates with hardware resources such as a CPU (or microcomputer), a RAM, a ROM, a storage / recording device, an electric / information device including an I / O, a computer, a server, and the like. You may implement with the form of the program to be made. In the form of a program, new functions can be distributed / updated and installed easily by recording them on a recording medium such as magnetic media or optical media or distributing them using a communication line such as the Internet.

  The induction heating cooker of the present invention is effective for induction heating cookers used in ordinary homes, restaurants, and the like because it can safely cook fried foods with high heating power.

DESCRIPTION OF SYMBOLS 1 Top plate 2 Cooking container 3 Heating coil 4 Infrared sensor 5 Commercial power supply 6 Rectification smoothing part 7 Inverter circuit 11 Heating control part 12 Operation part 12e Preheating mode selection key (preheating mode selection part)
DESCRIPTION OF SYMBOLS 13 1st thermal power determination means 14 1st temperature gradient calculation means 15 1st temperature difference calculation means 16 Notification part 17 Input power detection means 18 2nd thermal power determination means 19 2nd temperature gradient calculation means 20 2nd Temperature difference calculation means 26 Thermistor

Claims (8)

A top plate formed of a material that transmits infrared rays, a heating coil that is provided below the top plate and induction-heats a cooking vessel placed on the top plate, and an inverter that supplies high-frequency current to the heating coil A circuit, an operation unit for setting the operation mode of the inverter circuit and the heating output, an infrared sensor for detecting infrared rays radiated from the bottom surface of the cooking vessel and transmitted through the top plate, and an output of the infrared sensor And a first temperature difference for calculating a difference between a target temperature updated every first predetermined time and a temperature detected by the infrared sensor. A calculating means; a first temperature gradient calculating means for calculating a time change amount of a detected value of the temperature detected by the infrared sensor; and the first temperature difference calculation. And a first heating power determining unit that inputs the calculated value of the first temperature gradient calculating unit and determines the heating output, and the operation unit starts heating in the first heating mode and then When the increase amount of the output value of the infrared sensor with respect to the predetermined value exceeds the predetermined increase amount, the operation mode shifts to a standby mode in which heating is performed with a second heating output lower than the first heating output, and the operation unit is operated by the user during the standby mode. When the heating output is changed to the third heating output, a preheating mode selection unit for selecting a preheating mode for shifting to the heating mode for heating with the third heating output is provided, and the third heating is performed during the heating mode. An induction heating cooker that maximizes the output and updates the heating output by the first heating power determining means. The induction heating cooker according to claim 1, wherein the predetermined value is an output value of the infrared sensor before and after the start of heating in the first heating mode or an output value in a state where there is no light stored at the time of factory shipment. The induction heating cooker according to claim 1, wherein the infrared sensor includes an InGaAs photodiode. Input power integrating means for integrating the input power, and when the integrated value of the input power integrating means exceeds a predetermined integrated value during the heating mode, the update of the heating output by the first heating power determining means is stopped and selected. The induction heating cooker according to any one of claims 1 to 3, wherein heating is performed with a heating output. The induction heating cooker according to claim 4, wherein the predetermined integrated value is changed according to a heating output setting. The induction heating cooker according to any one of claims 1 to 5, wherein in the heating mode, the heating output is updated by the first heating power determining means when the setting of the heating output is equal to or greater than a predetermined heating output. A thermistor disposed under the top plate and detecting the temperature of the bottom surface of the cooking container via the top plate, and a difference between a target temperature updated every second predetermined time and a temperature detected by the thermistor. A second temperature difference calculating means for calculating; a second temperature gradient calculating means for calculating a temporal change amount of a detected value of the temperature detected by the thermistor; the second temperature difference calculating means; and the second temperature. Second heating power determining means for determining the heating output with the calculated value of the gradient calculating means as an input, and the first heating power determining means and the second heating power determining means operate in parallel during the heating mode. And the induction heating cooking appliance of any one of Claims 1-6 which employ | adopt a lower heating output and update a heating output. A program for causing a computer to execute at least one of the induction heating cookers according to any one of claims 1 to 7.

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