JP2012243704A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating cooker which properly controls a heating power when cooking a cooking object, especially when boiling noodles, without causing boiling over.SOLUTION: An induction heating cooker comprises a heating coil 3 heating a pan 1 as a heating object, a high-frequency inverter 4 supplying a current to the heating coil 3, a top plate 2 arranged on the heating coil 3 and on which the pan 1 is placed, infrared detection means 5 arranged below the top plate 2 for detecting infrared irradiated from a bottom face of the pan 1, temperature detection means 6 detecting a temperature of the pan 1 based on an output of the infrared detection means 5, diameter determination means 7 determining a diameter of the pan 1 based on output characteristics of the high-frequency inverter 4, and control means 8 controlling heating based on an output of the temperature detection means 6. The control means 8 decreases a thermal dose when it is detected that a temperature in the pan 1 reaches a boiling temperature. At this time, the control means 8 decreases a degree of decrement of the thermal dose in the case where the determined diameter of the pan 1 is large, and increases the degree of decrement of the thermal dose in the case where the diameter of the pan 1 is small. Accordingly, the heating power can be properly controlled regardless of a shape of the pan 1.

Description

  TECHNICAL FIELD The present invention relates to an induction heating cooker that can cook without spilling by properly controlling the heating power when cooking food, particularly noodles.

  The conventional cooking device measures the temperature in the pan from the temperature sensor at the bottom of the pan, and controls the thermal power so that it does not spill out occasionally with the noodle bowl (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-155659

  However, since the conventional method does not consider the shape of the pan as a heating object, a sufficient amount of heating cannot be supplied, or conversely, the amount of heating is too large to cause spillage. Moreover, since the timing when the food was put into the pan could not be detected quickly, there was a problem that the thermal power control could not be performed with high accuracy.

  This invention solves the said conventional subject, and it aims at providing the induction heating cooking appliance which can implement | achieve optimal thermal-power control in consideration of the characteristic of a heating target object.

  In order to solve the conventional problems, an induction heating cooker according to the present invention includes a heating coil for heating an object to be heated, a high-frequency inverter for supplying current to the heating coil, and a heating coil installed on the heating coil. A top plate on which the object is placed, infrared detection means for detecting infrared rays radiated from the bottom surface of the heating object installed under the top board, and the temperature of the heating object from the output of the infrared detection means Temperature detecting means for detecting the temperature, diameter determining means for determining the diameter of the object to be heated from the output characteristics of the high frequency inverter, and control means for controlling the heating based on the output of the temperature detecting means, the control means being the object to be heated When it is detected that the temperature inside the object has reached the boiling temperature, the heating amount is decreased. At this time, when the determined diameter of the heating object is large, the heating amount to be reduced is reduced, and when the diameter of the heating object is small, the heating amount to be decreased is increased to supply the optimum heating amount when maintaining boiling. can do. In addition, when the temperature falls below a determination value corresponding to the diameter of the object to be heated, it is possible to increase the amount of heating to be supplied at an optimum timing by determining that the cooked food has been added, and further When the temperature rises above a determination value corresponding to the diameter of the object, an excessive amount of heating or spilling can be suppressed by controlling with the amount of heating before the food is added.

  Since the induction heating cooker of the present invention can control the heating power in consideration of the characteristics of the object to be heated, it can supply the necessary amount of heating without excess or deficiency when cooking food such as noodles and suppresses spillage. be able to.

The block diagram which shows the structure of the induction heating cooking appliance in Embodiment 1 of this invention. The flowchart which shows the processing content in the control means in Embodiment 1 of this invention The graph which shows the relationship between the operating frequency and input current in Embodiment 2 of this invention The flowchart which shows the processing content in the diameter determination means in Embodiment 2 of this invention The graph which shows the relationship between the input current and coil current in Embodiment 3 of this invention The flowchart which shows the processing content in the diameter determination means in Embodiment 3 of this invention The graph which shows the relationship between the coil current and coil voltage in Embodiment 4 of this invention The flowchart which shows the processing content in the diameter determination means in Embodiment 4 of this invention The graph which shows the difference in the temperature change by the difference in the diameter of the heating target in Embodiment 5 of this invention The graph which shows the difference in the temperature change by the difference in the diameter of the heating target in Embodiment 6 of this invention The flowchart which shows the processing content of the cooking input determination process in the control means in Embodiment 6 of this invention. The graph which shows the difference in the temperature change by the difference in the diameter of the heating target in Embodiment 7 of this invention The flowchart which shows the processing content of the thermal power return determination process in the control means in Embodiment 7 of this invention

  The present invention includes a heating coil that heats a heating object, a high-frequency inverter that supplies current to the heating coil, a top plate that is installed on the heating coil and on which the heating object is placed, and the top plate From infrared detection means for detecting infrared rays radiated from the bottom surface of the heating object installed below, temperature detection means for detecting the temperature of the heating object from the output of the infrared detection means, and output characteristics of the high-frequency inverter A diameter determining means for determining the diameter of the object to be heated and a control means for controlling the heating based on the output of the temperature detecting means, and when the control means detects that the temperature in the object to be heated has reached the boiling temperature. Reduce the amount of heating. At this time, when the determined diameter of the heating object is large, the heating amount to be reduced is decreased, and when the diameter of the heating object is small, the heating amount to be decreased is increased, thereby affecting the shape of the heating object. The heating amount can be supplied without excess or deficiency.

  Specifically, the diameter determining means can make a determination based on the input current. In addition, the diameter determination means can also make a determination based on a coil current flowing in the heating coil, and can also make a determination based on a coil voltage generated in the heating coil. Thereby, the magnitude of the diameter of a heating target object can be easily determined with a simple structure.

  In addition, the control unit selects a determination value according to the diameter of the heating object, and when the output of the temperature detection unit decreases more than the determination value, the cooked material is put into the heating object. By determining and increasing the heating amount, it is possible to detect the input of the cooked food at the same timing regardless of the shape of the heating object.

  In addition, the control means may increase the amount of heating after adding the cooked food, regardless of the shape of the object to be heated, by increasing the amount of heating that is increased when the diameter of the object to be heated is larger than when it is small. The heating amount can be supplied without shortage.

  In addition, the control unit selects a determination value according to the diameter of the object to be heated, and when the output of the temperature detection unit rises more than the determination value after the food is charged, the heating amount before the food is charged By controlling at, excess heating amount can be suppressed, and furthermore, spillage can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
In FIG. 1, the first heating coil 3 a and the second heating coil 3 b for heating the pan 1 as a heating object, and the pan 1 at the upper part of the first heating coil 3 a and the second heating coil 3 b. A first high-frequency inverter 4a and a second high-frequency inverter that supply a high-frequency current to the top plate 2 to be held, the first heating coil 3a and the second heating coil 3b, respectively, and cause the pan 1 to generate heat by induction heating. 4b, infrared detection means 5 that is installed on the lower surface of the top plate 2 and detects infrared rays emitted from the bottom surface of the pan 1, and temperature detection means that detects the temperature of the pan 1 from the output of the infrared detection means 5 6 and the diameter determining means 7 for determining the diameter of the pan 1 from the inverter characteristics obtained from the first high-frequency inverter 4a, and the first heating coil 3a and the second heating coil 3b. And a control unit 8 for controlling that power.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, a power supply (not shown) is turned on to start heating. An induction magnetic field is generated in the first heating coil 3a and the second heating coil 3b from the first high-frequency inverter 4a and the second high-frequency inverter 4b by the control from the control means 8, and the pan 1 on the top plate 2 is heated. Is done.

  Here, when the temperature of the pan 1 rises, infrared rays corresponding to the temperature are emitted from the pan 1. Since the glass ceramic or the like used for the top plate 2 can efficiently transmit infrared rays having a wavelength range of 2.5 μm or less, the infrared detection means 5 is composed of, for example, a photodiode that can detect wavelengths of 2.5 μm or less. Infrared light in this wavelength range that has passed through the top plate 2 is incident on the infrared detection means 5. Further, the infrared detecting means 5 collects more infrared rays using a condensing lens and blocks infrared rays from other than the pan 1 to improve accuracy.

  In the temperature detection means 6, only the infrared rays from the pan 1 are incident on the infrared detection means 5, and the diode current corresponding to the amount of infrared rays is IV-converted and amplified to be converted into temperature. This temperature information is input to the control means 8, and the control means 8 calculates the temperature of the bottom of the pan 1 every second.

  At this time, an example of the thermal power control algorithm in the control means 8 is shown in FIG.

  In step (hereinafter referred to as S) 1, the diameter determining means 7 determines the diameter of the pan 1. In S2, the control means 8 calculates a temperature difference at a predetermined time of the output of the temperature detection means 6 every second, and determines whether or not it is continuously detected that the calculated temperature difference is within the predetermined temperature difference. If it is determined and continuously detected, it is determined that the water has boiled and the process proceeds to S3. If not detected, the process returns to S2. In S3, the control means 8 changes the heating power according to the diameter of the pan 1 to maintain boiling. In S4, it is determined by the control means 8 whether or not the cooked food has been put into the pan 1, and when the cooked food has been thrown in, the heating power is changed to an appropriate heating power. In S5, it is determined by the control means 8 whether or not the object to be heated in the pan 1 has returned to a temperature in the vicinity of boiling, and when it returns to a temperature close to boiling, the heating power obtained in S3 is changed.

  As described above, the temperature calculated by the temperature detecting means 6 via the infrared detecting means 5 can accurately detect the temperature change of the bottom surface of the pan 1, so that even if the food is thrown in the middle, the necessary heating is sufficient. An amount can be supplied and spillage can be suppressed.

(Embodiment 2)
With reference to the graph of FIG. 3, the process of determining the diameter of the pan 1 is demonstrated. When the first heating coil 3a is operated at a predetermined operating frequency fa, an input current I1 is generated. When the input current I1 is less than the determination value Ia, it can be determined that the first heating coil 3a is in an unloaded state, that is, the pan 1 is not placed on the first heating coil 3a. Thereby, the diameter of the pan 1 can be determined.

  Hereinafter, an example of an algorithm for determining the diameter of the pan 1 will be described with reference to FIG.

  In S11, an input current I1 when operating at a predetermined operating frequency fa is acquired. In S12, if the acquired input current I1 is greater than or equal to the determination value Ia, the process proceeds to S13, and if it is less than the determination value Ia, the process proceeds to S14. In S13, the diameter of the pot 1 is determined to be “large”, and the method for determining the diameter of the pot 1 is terminated. In S14, the diameter of the pot 1 is determined to be “small”, and the method for determining the diameter of the pot 1 is terminated.

  The input current determination value Ia is experimentally determined in advance as an optimum value.

  Further, in the above description, the heating coil is only divided into two, but if divided into a plurality, it is effective in terms of accuracy.

(Embodiment 3)
FIG. 5 is a graph for explaining another process for determining the diameter of the pan 1. When the input current Ib flows, the coil current Ic1 flows through the first heating coil 3a. When the coil current Ic1 is greater than or equal to the determination value Ic, it can be determined that the first heating coil 3a is in an unloaded state, that is, the pan 1 is not placed on the first heating coil 3a. Thereby, the diameter of the pan 1 can be determined.

  Hereinafter, an example of an algorithm for determining the diameter of the pan 1 will be described with reference to FIG.

  In S21, the coil current Ic1 when the input current Ib is supplied is acquired. In S22, if the acquired coil current Ic1 is greater than or equal to the determination value Ic, the process proceeds to S23, and if it is less than the determination value Ic, the process proceeds to S24. In S23, the diameter of the pot 1 is determined to be “small”, and the diameter determining process for the pot 1 is terminated. Moreover, in S24, the diameter of the pan 1 is determined to be “large”, and the determination processing of the diameter of the pan 1 is ended.

  The coil current determination value Ic is experimentally determined in advance as an optimum value.

  Further, in the above description, the heating coil is only divided into two, but if divided into a plurality, it is effective in terms of accuracy.

(Embodiment 4)
FIG. 7 is a graph for explaining another process for determining the diameter of the pan 1. When the input current Ib flows, a coil voltage Vd1 is generated in the first heating coil 3a. When the coil voltage Vd1 is equal to or higher than the determination value Vd, it can be determined that the first heating coil 3a is in an unloaded state, that is, the pan 1 is not placed on the first heating coil 3a. Thereby, the diameter of the pan 1 can be determined.

  Hereinafter, an example of an algorithm for determining the diameter of the pan 1 will be described with reference to FIG.

  In S31, the coil voltage Vd1 when the input current Ib is supplied is acquired. In S32, if the acquired coil voltage Vd1 is not less than the determination value Vd, the process proceeds to S33, and if it is less than the determination value Vd, the process proceeds to S34. In S33, the diameter of the pot 1 is determined to be “small”, and the diameter determining process for the pot 1 is terminated. In S34, the diameter of the pot 1 is determined to be “large”, and the diameter determining process for the pot 1 is terminated.

  The coil voltage determination value Vd is experimentally determined in advance as an optimum value.

  Further, in the above description, the heating coil is only divided into two, but if divided into a plurality, it is effective in terms of accuracy.

(Embodiment 5)
FIG. 9 is a graph showing the difference in temperature change due to the difference in the diameter of the pan 1 when the heating amount is reduced after boiling. When the diameter of the pan 1 is large, the heat radiation area is larger than that of the pot 1 having a small diameter, and thus the temperature drops at the same heating amount. Therefore, what is necessary is just to change the heating amount at the time of boiling maintenance according to the diameter of the pan 1, in order to maintain boiling irrespective of the diameter of the pan 1. FIG. At this time, when the heating amount at the time of boiling maintenance when the diameter of the pan 1 is small is W21 and the heating amount at the time of boiling maintenance when the diameter of the pan 1 is large is W22, the following equation is established.

W21 <W22 (Formula 1)
As described above, if the amount of heating at the time of boiling maintenance is changed according to the diameter of the pan 1, the pan 1 can be heated regardless of the shape of the pan 1.

(Embodiment 6)
In FIG. 10, the process which detects that the foodstuff was thrown into the pan 1 is shown on a graph. If the cooked food is thrown in while maintaining boiling, the temperature will drop unless the heating power is changed because of the increase in the number of objects to be heated. It will slow down the temperature change to the bottom. Therefore, in order to detect that the cooked food has been thrown in at the same timing, a determination value as to whether the cooked food has been thrown in may be selected according to the diameter of the pot 1. At this time, if the determination value when the diameter of the pot 1 is small is Te1, and the determination value when the diameter of the pot 1 is large is Te2, the following relational expression is established.

Te1 <Te2 (Formula 2)
Hereinafter, an example of an algorithm for detecting the input of the cooked product will be described with reference to FIG.

  In S41, a reference temperature Tk0 is acquired. In S42, a determination value Te corresponding to the size of the diameter of the pan 1 is selected. In S43, the temperature Tk is acquired. In S44, if the difference between the reference temperature Tk0 and the acquired temperature Tk is greater than or equal to the determination value Te, the process proceeds to S45, and if it is less than the determination value Te, the process returns to S43. In S45, the heating power is changed according to the diameter of the pot 1.

  The determination value Te is experimentally determined in advance as an optimum value.

  Moreover, it is the thermal power after the introduction of the cooked food is determined. If the thermal power when the diameter of the pan 1 is small is W31, and the thermal power when the diameter of the pan 1 is large is W32, the one with the larger diameter of the pan 1 However, since the heat radiation area is large, the following relational expression is established.

W31 <W32 (Formula 3)
At this time, in the above description, there are only two kinds of diameters of the pot 1, but if the diameter of the pot 1 is discriminated into a plurality of kinds, it is effective in terms of accuracy.

  As described above, by selecting the determination value according to the size of the diameter of the pan 1, it is possible to detect that the cooked food has been introduced at the same timing. Moreover, by selecting the heating power after detection according to the size of the diameter of the pan 1, the cooked food can be similarly heated regardless of the type of the pan 1.

(Embodiment 7)
In FIG. 12, the process which returns to the heating power at the time of normal boiling maintenance after a cooked material is thrown into the pan 1 and a heating power is changed is shown in a graph. Since the food sinks into the bottom of the pan 1 after the food is charged, the temperature at the bottom of the pan 1 may be lower than before the food is charged even though the water in the pot 1 is boiling. In this case, it is necessary to carry out excessive heating in order to return to the temperature before the food is added, which is not efficient. Therefore, when the necessary amount of heating is given to the food sinking to the bottom of the pan 1, the temperature of the bottom of the pan 1 rises. Therefore, when the temperature of the bottom of the pan 1 rises above a predetermined temperature, normal boiling is maintained. If it is changed to the heating power, it can be heated efficiently. On the other hand, the smaller the diameter of the pan 1, the deeper the water depth is, even at the same amount of water, so the temperature rises more slowly. To change the heating power at the same timing, the judgment value is set according to the size of the diameter of the pan 1. Must be selected. At this time, if the determination value when the diameter of the pan 1 is small is Tg1, and the determination value when the diameter of the pan 1 is large is Tg2, the following relational expression is established.

Tg1 <Tg2 (Formula 4)
Hereinafter, an example of an algorithm for returning to normal boiling-maintenance heating power after changing the heating power by using the cooked product will be described with reference to FIG.

  In S51, a reference temperature Tx0 is acquired. In S52, the determination value Tg corresponding to the size of the diameter of the pan 1 is selected. In S53, the temperature Tx is acquired. In S54, if the difference between the acquired temperature Tx and the reference temperature Tx0 is not less than the determination value Tg, the process proceeds to S55, and if it is less than the determination value Tg, the process returns to S53. In S55, the heating power is changed to that before the food is added.

  The determination value Tg is experimentally determined in advance as an optimum value.

  At this time, there are only two types of thickness of the bottom of the pan 1 in the above description, but it is effective in terms of accuracy if the thickness of the bottom of the pan 1 is discriminated into a plurality of types.

  As described above, by selecting the determination value according to the thickness of the bottom of the pan 1, the cooked product is charged at the same timing and the heating power is changed, and then it can be returned to the normal boiling maintenance heating power.

  As described above, the induction heating cooker according to the present invention can accurately detect the temperature regardless of the shape of the bottom surface of the pan 1, and as a result, the heating power is appropriately controlled when the food, particularly noodles, is boiled. Therefore, it can be cooked without spilling, so it can be applied to various induction heating cookers such as home use and business use.

1 Pan (object to be heated)
2 Top plate 3a 1st heating coil 3b 2nd heating coil 4a 1st high frequency inverter 4b 2nd high frequency inverter 5 Infrared detection means 6 Temperature detection means 7 Diameter determination means 8 Control means

Claims (5)

A heating coil for heating an object to be heated;
A high-frequency inverter for supplying current to the heating coil;
Installed on top of the heating coil, and a top plate on which the heating object is placed;
Infrared detector that is installed under the top plate and detects infrared rays emitted from the bottom surface of the heating object,
Temperature detection means for detecting the temperature of the heating object from the output of the infrared detection means;
Diameter determining means for determining the diameter of the heating object from the output characteristics of the high frequency inverter;
Control means for controlling heating from the output of the temperature detection means,
The control means reduces the heating amount when detecting that the temperature in the heating object has reached the boiling temperature, and reduces the heating amount when the diameter of the heating object determined by the diameter determination means is large. An induction heating cooker that reduces the amount and increases the amount of heating to be reduced when the diameter of the heating object is small. The induction heating cooker according to claim 1, wherein the diameter determination means performs determination based on any one of an input current, a coil current flowing through the heating coil, and a coil voltage generated at the heating coil. The control means selects a determination value according to the diameter of the heating object, and when the output of the temperature detection means decreases more than the determination value, it determines that the cooked food has been put into the heating object. The induction heating cooker according to claim 1 or 2, wherein the heating amount is increased. The induction according to any one of claims 1 to 3, wherein the control means increases the amount of heating after increasing the amount of heating after charging the cooked food, when the diameter of the object to be heated is larger than when it is small. Cooking cooker. The control means selects a determination value according to the diameter of the object to be heated, and when the output of the temperature detection means rises above the determination value after throwing the food, the heating amount before throwing the food The induction heating cooking appliance of any one of Claims 1-4 which controls.

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