JP4839682B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker using an infrared sensor.

Conventionally, in order to improve the responsiveness of temperature detection, an induction heating cooker that detects the temperature of the load pan by detecting the infrared intensity output from the load pan on the top plate with an infrared sensor is known. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 3-184295

  However, in the conventional configuration, although the responsiveness of temperature detection is improved by using an infrared sensor, there is an induction heating cooker that can heat a low-resistance load pan such as aluminum or copper with low permeability. Will not be able to accurately detect the temperature. That is, this type of induction heating cooker needs to reduce the buoyancy generated between the heating coil and the load pan during induction heating. As a countermeasure, when a buoyancy reduction plate made of a nonmagnetic metal is provided above the heating coil, the buoyancy reduction plate receives magnetic flux from the heating coil and rises to about 300 to 400 ° C. by self-heating. Therefore, the infrared rays radiated from the buoyancy reduction plate are several tens of times higher than the infrared rays radiated from the bottom of the load pan at 100 to 200 ° C., and a part of the infrared rays emitted from the buoyancy reduction plate is directly or Reflecting the top plate and entering the infrared sensor, the infrared sensor cannot accurately detect the temperature. Thereby, sufficient thermal power was not obtained for desired cooking, and cooking performance deteriorated.

  The present invention solves the above-mentioned conventional problems, and even in an induction heating cooker that can heat a load pan such as aluminum, induction that realizes control with good response by an infrared sensor and improves cooking performance. An object is to provide a cooking device.

In order to solve the above conventional problems, the induction heating cooker of the present invention includes an inverter circuit for heating a load pan on the top plate by supplying a high-frequency current to the heating coil, the load pot to heat by the inverter circuit a pot type determination means for determining whether a magnetic pot nonmagnetic pan or an iron-based aluminum-based, the load pan buoyancy generated during heating of the nonmagnetic pot placed aluminum-based between the top plate and the heating coil non magnetic metal buoyancy reduction plate for reducing an infrared sensor for detecting infrared radiation from the load pan, and temperature calculation means for calculating the temperature of the load pan from the output of the infrared sensor at said temperature calculating means and control means in response to the calculated temperature to control the output of said inverter circuit, wherein if it is determined that the non-magnetic pan aluminum species in the pot type determination means Is obtained by the increased value of the detected temperature of the infrared sensor due to self-heating of the buoyancy reduction plate to correct the detected temperature to subtract from the temperature detected by said temperature calculation means.

  As a result, even in an induction heating cooker that can heat a load pan such as aluminum, the influence of infrared rays incident on the infrared sensor from the buoyancy reduction plate for buoyancy reduction is corrected, and control with good responsiveness by the infrared sensor To improve cooking performance.

  The induction heating cooker of the present invention can also realize control with good responsiveness by an infrared sensor and improve cooking performance even in an induction heating cooker that can heat a load pan such as aluminum.

A first aspect of the present invention is an inverter circuit for heating a load pan on the top plate by supplying a high-frequency current to the heating coil, the load pan is heated by the inverter circuit or a non-magnetic pan or an iron-based magnetic pot aluminum-based a pot type determination means for determining a non-magnetic metal buoyancy reduction plate for reducing the load pan buoyancy generated during heating of the nonmagnetic pot placed aluminum-based between the top plate and the heating coil, wherein control and infrared sensor for detecting infrared radiation from the load pan, and temperature calculation means for calculating the temperature of the load pan from the output of the infrared sensor, the output of the inverter circuit in accordance with the calculated temperature at the temperature calculating means and control means for, wherein when it is determined that the non-magnetic pan aluminum species in the pot-type judging means, the infrared due to self-heating of the buoyancy reduction plate With the induction heating cooker of the rising value of the detected temperature of capacitors and to correct the detected temperature by said temperature calculation means, even in the induction heating cooker which allows heating load pan, such as aluminum, buoyancy reduction Therefore, it is possible to correct the influence of infrared rays incident on the infrared sensor from the buoyancy reduction plate for realizing high-responsive control by the infrared sensor and improve cooking performance.

The second invention is an inverter circuit for heating a load pan on a top plate by supplying a high-frequency current to a heating coil, and whether the load pan heated by the inverter circuit is an aluminum-based non-magnetic pan or an iron-based magnetic pan. A non-metallic metal buoyancy reduction plate that reduces the buoyancy of the load pan that is disposed between the top plate and the heating coil and that is generated when the aluminum-based nonmagnetic pan is heated; An infrared sensor for detecting infrared radiation from the load pan, a temperature calculating means for calculating the temperature of the load pot from the output of the infrared sensor, and controlling the output of the inverter circuit according to the temperature calculated by the temperature calculating means and control means for, wherein when it is determined that the non-magnetic pan aluminum species in the pot-type judging means, the temperature calculated in accordance with the output of the inverter circuit By correcting the detected temperature by stages, it is possible to correct the detected temperature of the infrared so as to correspond to the temperature rise of the different buoyancy reduction plate in accordance with the output of the inverter circuit.

The third invention is an inverter circuit for heating a load pan on a top plate by supplying a high-frequency current to a heating coil, and whether the load pan heated by the inverter circuit is an aluminum-based non-magnetic pan or an iron-based magnetic pan. A non-metallic metal buoyancy reduction plate that reduces the buoyancy of the load pan that is disposed between the top plate and the heating coil and that is generated when the aluminum-based nonmagnetic pan is heated; An infrared sensor for detecting infrared radiation from the load pan, a temperature calculating means for calculating the temperature of the load pan from the output of the infrared sensor, a second temperature detecting means for detecting the temperature of the buoyancy reduction plate, and according to the calculated temperature at the temperature calculating means and control means for controlling the output of said inverter circuit, said control means determines that the non-magnetic pan aluminum species in the pot type determination means If the, according to the temperature detected by the second temperature sensing means, by which is adapted to correct the detected temperature by said temperature calculation means, the temperature sensing optimal for by the infrared sensor according to the temperature of the buoyancy reduction plate Correction can be performed, and the accuracy of temperature control by the infrared sensor can be improved.

  According to a fourth aspect of the invention, in particular, in the third aspect of the invention, the second temperature detecting means is configured by the second infrared sensor, so that the temperature of the buoyancy reduction plate is detected with high sensitivity, and the pan using the infrared sensor. The accuracy of temperature detection can be improved.

  According to a fifth aspect of the invention, in particular, in the third or fourth aspect of the invention, the second temperature detecting means is configured to detect the temperature of the outer peripheral portion of the heating coil, so that the second temperature can be achieved with a simple configuration. The detection accuracy of the detection means can be improved, and the accuracy of detection of the pan temperature by the infrared sensor can be improved.

  In a sixth aspect of the invention, in particular, in any one of the third to fifth aspects of the invention, the temperature calculation means switches the amplification range of the signal output from the infrared sensor according to the detected temperature of the second temperature detection means. Thus, the pan temperature can be detected by the infrared sensor with the optimum amplification factor without the output of the infrared sensor being over the range due to the influence of the infrared radiation from the buoyancy reduction plate.

  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)
1 to 3 show an induction heating cooker according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the induction heating cooker in the present embodiment includes a load pan 11, a top plate 12 on which the load pan 11 is placed, a heating coil 13 that heats the load pan 11, and a heating coil 13. An inverter circuit 14 for supplying a high-frequency current, and a buoyancy reduction plate 15 made of nonmagnetic metal that is disposed between the top plate 12 and the heating coil 13 and reduces the buoyancy of the load pan 11 generated when the aluminum-based nonmagnetic pan is heated. The load pan 11 heated by the inverter circuit 14 includes a pan type determination means 16 for determining whether the load pan 11 is an aluminum-based non-magnetic pan or an iron-based magnetic pan. Further, the load sensor is composed of an infrared sensor 17 for detecting infrared radiation from the load pan 11 heated by the inverter circuit 14, temperature calculating means 18 for calculating the load pan temperature from the output of the infrared sensor 17, and a thermistor. 11 is also provided with a temperature detecting means 19 for detecting the pan bottom temperature of 11 through the top plate 12 and a control means 20 for controlling the output of the inverter circuit 14 in accordance with the temperature calculated by the temperature calculating means 18. Note that outputs from the pan type determination unit 16 and the temperature detection unit 19 are also input to the control unit 20.

  And the control means 20 correct | amends the detection temperature by the temperature calculation means 18, when it determines with the pan seed | species determination means 16 that it is an aluminum-type nonmagnetic pot.

  The operation | movement is demonstrated about the induction heating cooking appliance comprised as mentioned above.

  When the high frequency current is supplied to the heating coil 13, the load pan 11 placed above the heating coil 13 is heated. Infrared rays corresponding to the temperature of the pan are radiated from the bottom of the load pan 11, and as shown in FIG. 2, the infrared radiation 21 emitted from the load pan 11 passes through the top plate 12 and is input to the infrared sensor 17. The Infrared radiation 22 from the buoyancy reduction plate 15 disposed between the top plate 12 and the heating coil 13 is also input to the infrared sensor 17. The infrared radiation 22 from the buoyancy reduction plate 15 may be input directly to the infrared sensor 17 from the buoyancy reduction plate 15, or may be input to the infrared sensor 17 by reflecting the top plate 12. The temperature calculation means 18 calculates the temperature of the load pan 11 based on the input signal from the infrared sensor 17, and the control means 20 controls the current flowing through the heating coil 13 so as to be in the set heating state.

  The pot type determination means 16 determines the pot type according to the output of the inverter circuit 14 when supplying high-frequency current to the heating coil 13, and the pot type determination means 16 determines that the pot is an iron-based magnetic pot. In this case, the control means 20 supplies a high frequency current of about 20 kHz to the heating coil 13. When heating the magnetic pan, since the current flowing through the heating coil 13 is small, the buoyancy reduction plate 15 hardly generates heat by the magnetic flux from the heating coil 13.

  As shown in FIG. 3 as an example of the load pan temperature and the temperature detected by the infrared sensor, in the temperature detection by the infrared sensor 17, the infrared radiation 22 from the buoyancy reduction plate 15 is detected by the infrared radiation 21 from the load pan 11. Therefore, the control unit 20 controls the output of the inverter circuit 14 based on the detection result of the temperature calculation unit 18 and the detection result of the temperature detection unit 19 so that the temperature of the load pan 11 becomes a predetermined temperature or less. To do.

  On the other hand, when the pot type determination means 16 determines that the pot is an aluminum-based nonmagnetic pot, the control means 20 supplies a high-frequency current of about 60 kHz to the heating coil 13. When heating a non-magnetic pan having a low magnetic permeability such as aluminum or copper, a large amount of current is passed through the heating coil 13 to increase the amount of magnetic flux, so that the self-heating of the buoyancy reduction plate 15 also increases. The buoyancy reduction plate 15 is made of a nonmagnetic metal material in order to suppress heat generation due to the magnetic flux from the heating coil 13, but when the load pan 11 is a nonmagnetic pan, the temperature of the buoyancy reduction plate 15 is 300 to 400 ° C. May rise. As a result, as shown in FIG. 3, under the influence of the infrared radiation 22 from the buoyancy reduction plate 15, the temperature detection by the infrared sensor 17 outputs a temperature ΔT higher than the actual temperature of the load pan 11, The control means 20 corrects ΔT lower from the detection result of the temperature calculation means 18 and controls the output of the inverter circuit 14 so that the temperature of the load pan 11 becomes a predetermined temperature or less.

  Further, even when the pot type determination means 16 determines that the pot is a non-magnetic pot, the temperature of the buoyancy reduction plate 15 changes according to the output of the inverter circuit 14, so that the control means 20 determines from the temperature detection result by the temperature calculation means 18. Change the correction amount so that it is large at high firepower and small at low firepower.

  As described above, in the present embodiment, when the pot type determining means 16 determines that the load pan 11 is a nonmagnetic pan, the temperature detection result by the infrared sensor 17 is corrected. Temperature control with good responsiveness by the infrared sensor 17 is possible without being affected by the self-heating of the reduction plate 15.

  Moreover, since the correction amount of the temperature detection result in the infrared sensor 17 is changed according to the output of the inverter circuit 14, the temperature control by the infrared sensor 17 becomes possible with the correction amount adapted to each heating power.

(Embodiment 2)
FIG. 4 shows an induction heating cooker according to Embodiment 2 of the present invention. The same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the temperature of the buoyancy reduction plate 15 extending from the outer periphery of the heating coil 13 to the outside is detected by including the second temperature detection means 23 configured by the second infrared sensor. Thereby, instead of the first embodiment in which the temperature detected by the temperature calculating means 18 is corrected when the pot type determining means 16 determines that it is an aluminum-based nonmagnetic pot, the control means 20 The temperature detected by the temperature calculating means 18 is corrected according to the temperature detected by the temperature detecting means 23. In addition, in order to guide the infrared radiation from the buoyancy reduction plate 15 to the second temperature detection means 23, a light guide tube 24 made of a metal material with good reflectivity is provided.

  The operation | movement is demonstrated about the induction heating cooking appliance comprised as mentioned above.

  When heating is started and a high-frequency current is supplied to the heating coil 13, when the material of the load pan 11 is a non-magnetic pan such as aluminum or copper, the temperature of the buoyancy reduction plate 15 may rise to 300 to 400 ° C. Under the influence of the infrared radiation 22 from the buoyancy reduction plate 15, the temperature detection by the infrared sensor 17 outputs a temperature ΔT higher than the actual temperature of the load pan 11 (as described in the first embodiment). On the other hand, the temperature of the buoyancy reduction plate 15 detects the infrared rays emitted from the buoyancy reduction plate 15 by the second temperature detection means 23 through the light guide tube 24, and the control means 20 detects the second temperature detection means. 23, the amplification range of the temperature calculation means 18 is switched according to the detected temperature at 23, and corrected by ΔT lower than the detection result of the temperature calculation means 18, so that the temperature of the load pan 11 becomes a predetermined temperature or less. 14 outputs are controlled.

  The temperature correction value changes according to the detected temperature of the second temperature detecting means 23. When the detected temperature of the second temperature detecting means 23 is high, the correction amount is increased, and the detected temperature of the second temperature detecting means 23 is increased. When the value is low, the correction amount is set to be small.

  Further, the amplification range also changes in accordance with the detection temperature of the second temperature detection means 23. When the detection temperature of the second temperature detection means 23 is high, the amplification range is lowered and the detection of the second temperature detection means 23 is performed. When the temperature is high, the amplification range is set high.

  In the present embodiment, the second temperature detection means 23 is constituted by an infrared sensor. However, the same effect can be obtained even if the buoyancy reduction plate 15 is directly detected by a thermistor.

  In addition, since the buoyancy reduction plate 15 is made of a non-magnetic metal material having good heat conduction, the second temperature detection means 23 is disposed on the outer peripheral portion of the heating coil 13. The same effect can be obtained by detecting the temperature of the inner peripheral portion of the heating coil 13.

  Further, although the light guide tube 24 is arranged in the second temperature detecting means 23, the viewing angle of the infrared sensor which is the second temperature detecting means 23 is sufficiently narrow, and the temperature of the buoyancy reducing plate 15 is detected. If possible, the same effect can be obtained without the light guide tube 24.

  As described above, in the present embodiment, it is possible to perform optimum correction of temperature detection by the infrared sensor 17 in accordance with the temperature of the buoyancy reduction plate 15 and to improve the accuracy of temperature control by the infrared sensor 17. In addition to the influence of infrared radiation due to self-heating of the buoyancy reduction plate 15, the influence of infrared radiation accompanying the temperature rise of the buoyancy reduction plate 15 due to heat transfer from the load pan 11 after cooking fried food or grilled food is also reduced. Can do.

  Moreover, since the 2nd temperature detection means 23 is comprised by the infrared sensor, the temperature of the buoyancy reduction board 15 is detected with sufficient sensitivity, and the detection accuracy of the temperature of the load pan 11 by the infrared sensor 17 can be improved. it can.

  Moreover, since the 2nd temperature detection means 23 detects the temperature of the outer peripheral part of the heating coil 13, it improves the detection accuracy of the 2nd temperature detection means 23 by simple structure, and the infrared sensor 17 The accuracy of temperature detection of the load pan 11 can be improved.

  Further, since the amplification range of the signal output from the infrared sensor 17 is switched in accordance with the temperature detected by the second temperature detection means 23, the output of the infrared sensor 17 is affected by the influence of infrared radiation from the buoyancy reduction plate 15. Without being over, the temperature of the load pan 11 can be detected by the infrared sensor 17 with an optimum amplification factor.

  As described above, the induction heating cooker according to the present invention realizes control with good responsiveness by the infrared sensor and improves cooking performance even in the induction heating cooker that can heat a load pan such as aluminum. Therefore, it can be applied to all induction heating cookers regardless of the form of use.

Sectional drawing of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the infrared radiation from the load pan and the buoyancy reduction plate of the same induction heating cooker The figure which shows the detection temperature of the load pan and the infrared sensor of the induction heating cooker Sectional drawing of the induction heating cooking appliance in Embodiment 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Load pan 12 Top plate 13 Heating coil 14 Inverter circuit 15 Buoyancy reduction board 16 Pan kind determination means 17 Infrared sensor 18 Temperature calculation means 20 Control means 23 2nd temperature detection means

Claims (6)

An inverter circuit for heating a load pan on the top plate by supplying a high-frequency current to the heating coil, pan type determination determines whether magnetic pot nonmagnetic pan or an iron-based load pot aluminum-based heating in the inverter circuit means a non-magnetic metal buoyancy reduction plate for reducing buoyancy of the load pan occurring during heating of the nonmagnetic pot placed aluminum-based between the top plate and the heating coil, infrared radiation from the load pan comprising an infrared sensor for sensing the temperature calculation means for calculating the temperature of the load pan from the output of the infrared sensor, and control means for controlling the output of said inverter circuit in accordance with the calculated temperature at the temperature calculating means , wherein when it is determined that the non-magnetic pan aluminum species in the pot type determination means, of the infrared sensor due to self-heating of the buoyancy reduction plate detected temperature The induction heating cooker so as to correct the detected temperature rise value to subtract from the temperature detected by said temperature calculation means. An inverter circuit for heating a load pan on the top plate by supplying a high-frequency current to the heating coil, pan type determination determines whether magnetic pot nonmagnetic pan or an iron-based load pot aluminum-based heating in the inverter circuit means a non-magnetic metal buoyancy reduction plate for reducing buoyancy of the load pan occurring during heating of the nonmagnetic pot placed aluminum-based between the top plate and the heating coil, infrared radiation from the load pan comprising an infrared sensor for sensing the temperature calculation means for calculating the temperature of the load pan from the output of the infrared sensor, and control means for controlling the output of said inverter circuit in accordance with the calculated temperature at the temperature calculating means , wherein when it is determined that the non-magnetic pan aluminum species in the pot-type determination means, by the temperature calculation means according to the output of the inverter circuit Induction heating cooker so as to correct the knowledge temperature. An inverter circuit for heating a load pan on the top plate by supplying a high-frequency current to the heating coil, pan type determination determines whether magnetic pot nonmagnetic pan or an iron-based load pot aluminum-based heating in the inverter circuit means a non-magnetic metal buoyancy reduction plate for reducing buoyancy of the load pan occurring during heating of the nonmagnetic pot placed aluminum-based between the top plate and the heating coil, infrared radiation from the load pan an infrared sensor for detecting a temperature calculating means for calculating the temperature of the load pan from the output of the infrared sensor, a second temperature detecting means for detecting a temperature of the buoyancy reduction plate, calculated at the temperature calculating means and control means for controlling the output of said inverter circuit in response to temperature, wherein when it is determined that the non-magnetic pan aluminum species in the pot-type judging means, before Depending on the detected temperature of the second temperature sensing means, induction heating cooker so as to correct the detected temperature by said temperature calculation means. The induction heating cooker according to claim 3, wherein the second temperature detection means is constituted by a second infrared sensor. The induction heating cooker according to claim 3 or 4, wherein the second temperature detection means is configured to detect the temperature of the outer peripheral portion of the heating coil. The induction heating cooker according to any one of claims 3 to 5, wherein the temperature calculation means switches the amplification range of the signal output from the infrared sensor according to the temperature detected by the second temperature detection means.