JP2006040778A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker capable of coping with wide range temperature detection without errors in the detected temperature, and precisely detecting temperature of an object to be heated on a top plate to control heating. <P>SOLUTION: This induction heating cooker is provided with an infrared detection means 6 detecting infrared ray from the object to be heated, a first temperature detection means 9 detecting the temperature of the object to be heated from the output of the infrared detection means 6, a second temperature detection means 10 detecting the temperature of the top plate on which the object to be heated is mounted, and a control means 11 controlling a heating output according to the output of the temperature detection means 9, 10. The first temperature detection means 9 has an output subtraction means 13 subtracting the output of the infrared detection means 6 according to the output of the temperature detection means 10 and an amplification means 12 amplifying the output. The control means 11 controls the heating output to a heating coil according to the output of the amplification means 12. Therefore, since wide range temperature detection can be coped with by amplifying after subtracting an dosage of infrared rays, the temperature of the object to be heated on the top plate can be precisely detected without errors in the temperature detection. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an induction heating cooker that can accurately detect the temperature of an object to be heated such as a pan on a top plate.

2. Description of the Related Art Conventionally, in this type of induction heating cooker, an infrared sensor is disposed on the lower surface of the top plate, and infrared rays from an object to be heated are detected through the top plate (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 3-184295

  However, in the conventional configuration, since the infrared radiation energy has a large difference between a low temperature of 100 ° C. or less and a high temperature of about 300 ° C., it is possible to detect a wide range of temperatures simply by placing an infrared sensor on the bottom surface of the top plate. In addition, there is a problem that an error occurs in the detected temperature because infrared radiation from the top plate is included.

  The present invention solves the above-mentioned conventional problems, can cope with a wide range of temperature detection, has no error in the detection temperature, and accurately detects the temperature of an object to be heated such as a pan on the top plate to control heating. An object of the present invention is to provide an induction heating cooker.

  In order to solve the above-described conventional problems, an induction heating cooker according to the present invention includes an infrared detector that is disposed on the lower surface of the top plate and detects infrared rays radiated from an object to be heated, and is heated from the output of the infrared detector. A first temperature detecting means for detecting an object temperature, a second temperature detecting means for detecting the temperature of the top board disposed on the lower surface of the top board, and a heating coil according to outputs of the first and second temperature detecting means Control means for controlling the power supplied to the first temperature detecting means, an output subtracting means for subtracting the output of the infrared detecting means according to the output of the second temperature detecting means, and the output subtracting means Amplifying means for amplifying the output, and the control means controls the heating output to the heating coil in accordance with the output of the amplifying means.

  As a result, since the amount of infrared light is subtracted and amplified, it can be used for a wide range of temperature detection, and there is no error in the detected temperature, and the temperature of the object to be heated, such as a pan on the top plate, is accurately detected for heating control be able to.

  The induction heating cooker according to the present invention can cope with a wide range of temperature detection, has no error in the detected temperature, and can accurately detect the temperature of an object to be heated such as a pan on the top plate and control the heating.

  In the first invention, a heating coil for heating an object to be heated, a top plate on which the object to be heated is placed above the heating coil, and an infrared ray radiated from the object to be heated arranged on the lower surface of the top plate. Infrared detection means for detecting, first temperature detection means for detecting the temperature of the object to be heated from the output of the infrared detection means, second temperature detection means for detecting the temperature of the top board disposed on the lower surface of the top board, Control means for controlling the power supplied to the heating coil in accordance with the outputs of the first and second temperature detection means, and the first temperature detection means outputs the output of the infrared detection means to the second temperature detection. An output subtracting means for subtracting according to the output of the means, and an amplifying means for amplifying the output of the output subtracting means, and the control means is an induction for controlling the heating output to the heating coil according to the output of the amplifying means. By using a cooking device, the amount of infrared rays can be reduced. To amplify after calculation, can accommodate a wide range of temperatures detected and no error in the detected temperature, the object to be heated temperature such as pan on the top plate can be accurately detected and heating control.

  In particular, the second invention has a switching means for switching the amplification factor of the amplifying means in the first invention, so that the temperature of the object to be heated can be stably detected more accurately according to the temperature change range of cooking. It can be done.

  In the third invention, in particular, in the first or second invention, the infrared detection means and the second temperature detection means are arranged on the bottom surface of the top plate between the inner and outer circumferences of the heating coil, so that the object to be heated is the most. Between the inner and outer circumferences of the heating coil that quickly reaches a high temperature, in particular, the temperature of the object to be heated can be detected in an empty pan or in a pan that conforms to the sky, and the temperature inside the pan with higher responsiveness.

  In particular, the fourth invention comprises a reflecting means for condensing infrared rays and guiding them to the infrared detecting means, and a magnetic shielding means arranged outside the reflecting means in the first invention, and the second temperature detecting means is provided. By arranging it outside the reflecting means and inside the magnetic shielding means, more infrared rays can be collected, and without being affected by the magnetic field by the magnetic shielding means, the temperature is detected by the infrared detecting means and the second temperature detecting means. Since detection is possible, the temperature of the object to be heated can be detected more accurately and stably.

  In particular, the fifth invention comprises a reflecting means for condensing infrared rays and guiding the infrared rays to the infrared detecting means, and a magnetic shielding means arranged outside the reflecting means in the first invention. By arranging it outside the magnetic shield means, it is possible to reduce the size of the magnetic shield means, reduce the effect of temperature rise due to the magnetic shield, and more accurately detect the temperature of the heated object with the infrared detection means. It is.

  According to a sixth aspect of the invention, in particular, in the fifth aspect of the invention, the magnetic-shielding means has a non-circular cross-sectional shape, and the second temperature detection means is disposed opposite to the notch, so that the infrared detection means detects it. Since the range and the range of the top plate detected by the second temperature detecting means are closer to each other, the temperature of the object to be heated can be detected more accurately and stably.

  In a seventh aspect of the invention, in particular, in the first aspect of the invention, the infrared detection means and the second temperature detection means are arranged at positions that are axisymmetric with respect to the central axis of the heating coil, so that the temperature detection position can be reduced. Since temperatures can be detected at positions that are axisymmetric with respect to the central axis of the heated object, the temperature of the object to be heated can be detected more accurately and stably.

  In an eighth aspect of the invention, in particular, in any one of the first to seventh aspects of the invention, the control means has an automatic cooking sequence, and the temperature information of the second temperature detection means is used to set the automatic cooking sequence. By performing the temperature control, it is possible to accurately detect the temperature in the temperature range according to the cooking menu with high accuracy.

  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)
FIGS. 1-5 shows the induction heating cooking appliance in Embodiment 1 of this invention.

  As shown in FIG. 1, the induction heating cooker in the present embodiment includes a heating coil 3 that heats a heated object 1 such as a pan, and a high-frequency current supplied to the heating coil 3 to cause the heated object 1 to be electromagnetically induced. An inverter 5 that generates heat, a top plate 2 on which the object to be heated 1 is placed above the heating coil 3, and an infrared detecting means that is disposed on the lower surface of the top plate 2 and detects infrared rays emitted from the bottom surface of the object to be heated 1. 6, first temperature detecting means 9 for detecting the bottom surface temperature of the object to be heated 1 from the output of the infrared detecting means 6, and second temperature detecting means for detecting the temperature of the top plate 2 disposed on the bottom surface of the top plate 2 10 and a control means 11 comprising a microcomputer for controlling the power supplied to the heating coil 3 in accordance with the outputs of the first and second temperature detection means 9 and 10. The infrared detecting means 6 is composed of a PIN photodiode (InGaAs) or the like, a cylindrical magnetic shield means 7 for preventing leakage magnetic flux from the heating coil 3 from passing through the infrared detecting means 6, and the object to be heated 1. And reflecting means 8 comprising a lens barrel that efficiently guides the infrared rays from the infrared rays to the infrared detecting means 6.

  As shown in FIG. 2, the first temperature detecting means 9 includes an output subtracting means 13 for subtracting the output of the infrared detecting means 6 in accordance with the output of the second temperature detecting means 10, and the output subtracting means. The control means 11 controls the heating output to the heating coil 3 according to the output of the amplifying means 12. The control unit 14 of the control unit 11 controls the degree of amplification of the output subtraction unit 13 and the amplification unit 12 based on information from the first temperature detection unit 9 and the second temperature detection unit 10, so that the object to be heated 1 The temperature is calculated and detected.

  In the induction heating cooker according to the present embodiment described above, when a power source (not shown) is turned on and a predetermined temperature is set with the operation switch, power is supplied from the inverter 5 to the heating coil 3 under the control of the control means 11. . When electric power is supplied to the heating coil 3, an induction magnetic field is generated in the heating coil 3, and the object to be heated 1 on the top plate 2 is induction heated. By this induction heating, the temperature of the object to be heated 1 rises, and the food in the object to be heated 1 is cooked.

  Here, the operation of the infrared detecting means 6 will be described. When the temperature of the article 1 to be heated rises, infrared rays corresponding to the temperature are emitted from the article 1 to be heated. In general, as shown in FIG. 3, the red radiant energy radiated from an object is determined by its temperature, and increases as the temperature increases and also expands to the short wavelength side. The top plate 2 in the induction heating cooker according to the present embodiment is made of glass ceramic or the like, and the glass ceramic can transmit 90% or more with respect to infrared rays having a wavelength range of 2.5 μm or less. When the temperature is higher than or equal to ° C., infrared radiation energy in a wavelength region of 2.5 μm or less is incident on the infrared detection means 6. Here, the infrared detecting means 6 is composed of a PIN photodiode (InGaAs) or the like that has a highly sensitive detection performance with respect to infrared rays in a wavelength range of 0.7 to 2.5 μm or less. With this PIN photodiode, an output current matching the temperature of the object to be heated 1 as shown in FIG. 4 is obtained. However, as shown in FIG. 4, the output current and the temperature of the heated object 1 are not linearly correlated. This is because the radiant energy increases rapidly as the temperature rises.

  Therefore, the amplification factor must be changed depending on the temperature range of temperature detection. This control will be described with reference to FIGS.

  The second temperature detecting means 10 is composed of a thermistor or the like that is in contact with the top plate 2 through silicon oil or the like, and can detect the temperature of the top plate 2 in a range where infrared rays from the heated object 1 are transmitted. . The top plate 2 has a transmittance of about 90% for infrared rays in the wavelength region of 2.5 μm or less, but the remaining 10% radiates the temperature of the top plate 2 itself to the infrared detecting means 6. Become. As shown in FIG. 5, when the temperature of the top 2 is high, such as 150 ° C., the temperature detection by the infrared detecting means 6 is greatly affected even by 10% radiant energy. In order to eliminate this influence, the output is subtracted by the output subtracting means 13 in accordance with the output of the second temperature detecting means 10. The subtracted output is amplified by the amplifying means 12 and input to the control unit 14 to calculate the detected temperature. In this case, since the influence of the top plate 2 that is a noise component is large, it is possible to detect the change of the infrared detecting means 6 corresponding to the temperature change of the heated object 1 with high resolution by subtracting before amplification. It becomes. Thereby, the influence of the temperature of the top plate 2 can be further reduced, and the temperature detection of the article 1 to be heated can be performed accurately.

  Here, the output subtracting means 13 subtracts the amount of infrared rays corresponding to the temperature of the top plate 2 as a voltage. However, if the temperature of the top plate 2 is within the temperature use range of the infrared detecting means 6, a heater or the like is used. The infrared detecting means 6 may be warmed. This is because if the top plate 2 and the infrared detecting means 6 are at the same temperature, the amount of infrared light is not transferred, and the amount of infrared light from the object to be heated 1 can be detected without being affected by the temperature of the top plate 2. is there.

  In the normal heating mode, the temperature of the object to be heated 1 is detected by lowering the amplification factor in order to detect changes up to 350 ° C. such as stir-fried food and prevention of overheating. The switching is performed by providing the amplifying means 12 with a gain switching means (not shown) in accordance with the cooking menu from the control unit 14. Since the temperature is low immediately after the start of heating, it is possible to increase the amplification factor and switch when the temperature rises. With this configuration, it is possible to accurately detect the temperature in the temperature range corresponding to the temperature state of the article 1 to be heated with high accuracy.

(Embodiment 2)
Next, the induction heating cooker in Embodiment 2 of this invention is demonstrated.

  The infrared detecting means 6 and the second temperature detecting means 10 shown in FIG. 1 are arranged at the center of the heating coil 3, and these are arranged between the inner and outer circumferences of the heating coil 3, that is, the lower surface of the top plate 2 at the intermediate point. , The temperature of the heated object 1 between the inner and outer circumferences of the heating coil 3 where the heated object 1 becomes the highest temperature is more responsive, particularly the temperature of the heated pot 1 in the pan and the pan in a state similar to the sky. It can be detected well.

  In addition, a reflection means 8 for condensing infrared rays and guiding the infrared detection means 6 to the infrared detection means 6, and a magnetic shield means 7 disposed outside the reflection means 8, the second temperature detection means 10 is disposed outside the magnetic shield means 7. By doing so, a configuration in which the magnetic shield means 7 is downsized is also possible, the influence of temperature rise due to the magnetic shield can be reduced, and the temperature of the heated object 1 can be stably detected by the infrared detection means 6 with higher accuracy. is there.

  Further, as shown in FIG. 6A, the second temperature detecting means 10 is arranged outside the reflecting means 8 that collects infrared rays and guides them to the infrared detecting means 6 and inside the magnetic shield means 7. In this way, more infrared rays can be collected and the temperature can be detected by the infrared detection means 6 and the second temperature detection means 10 without being affected by the magnetic field by the magnetic-shielding means 7, so that the accuracy can be improved. The temperature of the heated object 1 can be detected stably.

  Further, as shown in FIG. 6B, the magnetic-shielding means 7 has a non-circular cross-sectional shape (D-shape in the present embodiment), and the second temperature detection means 10 is disposed so as to face the notch 15. By doing so, since the range detected by the infrared detecting means 6 and the range of the top plate 2 detected by the second temperature detecting means 10 are closer to each other, the temperature of the heated object can be detected more accurately and stably. is there.

  Further, if the infrared detecting means 6 and the second temperature detecting means 10 are arranged at positions symmetrical with respect to the central axis of the heating coil 3, the temperature detecting position is set to the central axis of the object 1 to be heated. On the other hand, since the temperature can be detected at positions that are axially symmetric, the temperature of the object to be heated 1 can be detected more accurately and stably.

  Further, the control means 11 has an automatic cooking sequence. If the temperature control of the automatic cooking sequence is performed using the temperature information of the second temperature detection means 10, the temperature range corresponding to the cooking menu is set. Temperature detection can be performed accurately and with high accuracy. In addition, when it has an automatic sequence for performing cooking menus such as kettle and rice cooking, in order to detect temperatures in the range of 130 ° C. or lower, the amplification factor 12 is increased so that the region of 60 to 130 ° C. is a full range. What is necessary is just to make it detect.

  As described above, the induction heating cooker according to the present invention can cope with a wide range of temperature detection, has no error in the detected temperature, and accurately detects the temperature of an object to be heated such as a pan on the top plate. Therefore, it can be applied to various induction heating cookers such as general home use and business use.

The block diagram which shows the induction heating cooking appliance in Embodiment 1 of this invention Block diagram showing first and second temperature detection means and control means in the induction heating cooker Graph showing the distribution of infrared rays transmitted through the top plate and the sensitivity wavelength range of infrared detection means in the induction heating cooker The figure which shows the relationship between the output of the infrared detection means and temperature in the induction heating cooking appliance. Graph showing temperature detection data after correction in the same induction heating cooker (A) Plan view showing configuration examples of infrared detection means and second temperature detection means in Embodiment 2 of the present invention (b) Plan view showing another configuration example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heated object 2 Top plate 3 Heating coil 6 Infrared detection means 7 Magnetic-shield means 8 Reflection means 9 1st temperature detection means 10 2nd temperature detection means 11 Control means 12 Amplification means 13 Output subtraction means 15 Notch part

Claims (8)

A heating coil that heats the object to be heated, a top plate on which the object to be heated is placed above the heating coil, and an infrared detector that is disposed on the lower surface of the top plate and detects infrared rays emitted from the object to be heated. The first temperature detecting means for detecting the temperature of the object to be heated from the output of the infrared detecting means; the second temperature detecting means for detecting the temperature of the top plate disposed on the lower surface of the top plate; Control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detection means, wherein the first temperature detection means outputs the output of the infrared detection means in accordance with the output of the second temperature detection means. An induction heating cooker having an output subtracting means for subtracting and an amplifying means for amplifying the output of the output subtracting means, and the control means controls the heating output to the heating coil in accordance with the output of the amplifying means. The induction heating cooker according to claim 1, further comprising switching means for switching the amplification factor of the amplification means. The induction heating cooker according to claim 1 or 2, wherein the infrared detection means and the second temperature detection means are arranged on the lower surface of the top plate between the inner and outer periphery of the heating coil. Reflecting means for condensing infrared rays and guiding them to the infrared detecting means, and a magnetic shielding means arranged outside the reflecting means, and the second temperature detecting means is arranged outside the reflecting means and inside the magnetic shielding means. The induction heating cooker according to claim 1. The induction according to claim 1, further comprising a reflecting means for condensing the infrared rays and guiding the infrared rays to the infrared detecting means, and a magnetic shielding means arranged outside the reflecting means, and the second temperature detecting means is arranged outside the magnetic shielding means. Cooking cooker. The induction heating cooker according to claim 5, wherein the magnetic-shielding means has a non-circular cross-sectional shape, and the second temperature detection means is disposed to face the notch. The induction heating cooker according to claim 1, wherein the infrared detecting means and the second temperature detecting means are arranged at positions symmetrical with respect to the central axis of the heating coil. The induction heating cooker according to any one of claims 1 to 7, wherein the control means has an automatic cooking sequence and performs temperature control of the automatic cooking sequence using temperature information of the second temperature detection means. .

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