JP2011134644A - Induction heating cooking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an induction heating cooking device with a function that detects overheating even if a foreign matter is inserted between an object to be heated and a heating coil. <P>SOLUTION: In the induction heating cooking device, a control setting value changing means 109 changes a control setting value of a high frequency power supply means 104 to maintain power setting and a non-magnetized degree decision means 110 observes changes of the control setting value performed by the means and detects the overheating under circumstances where the foreign matter is inserted between the object 102 to be heated and the heating coil 103 by detecting the overheated state while monitoring the non-magnetized degree of the object 102, the non-magnetized degree being caused by the overheating. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating cooker having a function of detecting a heating state of a heated object when the heated object is heated using electromagnetic induction.

  Induction heating cookers that use a heating coil to heat an object to be heated such as a pot without using fire have been widely recognized in recent years because of their excellent features of safety, cleanliness, and high efficiency. Yes.

  The induction heating cooker can flatten the heated object mounting surface from the characteristic that non-contact heating can be performed. This leads to an advantage that the heating surface is easy to clean, and is one of the factors in the spread of induction heating cookers.

  However, in recent years, there has been an increasing number of misuses such as placing a sheet for preventing dirt under a pan in order to prevent dirt.

  Due to the heating characteristics of the induction heating cooker, if the object is thinly configured, the induction heating cooker has no effect even if a foreign object is inserted between the heating coil and the object to be heated. It can be performed.

  However, in such a situation, in a conventionally known induction heating cooker as described below, the temperature detecting means provided for preventing the heated object from being overheated correctly detects the temperature. You can't.

  For example, when the temperature detection means is a contact type temperature sensor such as a thermistor, the heat conduction is hindered by the foreign matter, and the sensitivity is lowered. Further, when the temperature detection means is a non-contact type temperature sensor such as an infrared sensor, temperature detection itself is impossible.

FIG. 11 is a block diagram showing a configuration of a conventional induction heating cooker.
In FIG. 11, high-frequency power supply means 1101, heating coil 1102 connected to high-frequency power supply means 1101, heated object 1103 such as a cooking pot, top plate 1104 on which heated object 1103 is placed, heated object 1103 The temperature detecting means 1105 for detecting the temperature and the heating control means 1106 for controlling the heating are configured.

  Specifically, as the temperature detection means 1105, a thermistor that is a contact type temperature sensor is closely attached to the top plate 1104 and detection is performed by heat conduction, or an infrared sensor that is a non-contact type temperature sensor is used to detect the object to be heated. May detect temperature.

  In such a configuration, a high-frequency magnetic field is generated from the heating coil 1102 by the high-frequency current supplied by the high-frequency power supply means 1101, and the object 1103 to be heated is heated due to the eddy current due to electromagnetic induction.

  In order to change or stabilize the input power, the control means (not shown) of the high frequency power supply means 1101 is driven by the high frequency power supply means 1101, the conduction ratio of the switching element (not shown), or the input of the high frequency power supply means 1101 (not shown). The output of the high-frequency power supply means 1101 is controlled by changing the step-up ratio of the step-up means for changing the voltage.

  The control means 1106 detects the temperature of the object to be heated 1103 by the temperature detection means 1105, and controls the output of the high frequency power supply means 1101 so that the temperature of the object to be heated 1103 is around 200 ° C., for example, when cooking fried food. Alternatively, when the cooking pan that is the object to be heated 1103 has no contents, the protective operation of stopping the heating is performed.

  Further, a method has been proposed in which the temperature of the object to be heated 1103 is detected based on a change in the control set value of the high-frequency power supply unit 1101 (see, for example, Patent Document 1).

JP 2004-247237 A

  However, in the above-described conventional configuration, the induction heating cooker can be used as long as the foreign object is inserted between the heating coil and the object to be heated as long as the object is thin due to the heating characteristics of the induction heating cooker. Although the object to be heated can be induction-heated without being affected, there is a problem that the temperature detection means provided for preventing the object to be heated from being overheated cannot correctly detect the temperature.

  For example, when the temperature detecting means is a contact type temperature sensor such as a thermistor, the heat conduction is hindered by a foreign substance, so the sensitivity is lowered. When the temperature detecting means is a non-contact type temperature sensor such as an infrared sensor, the temperature is low. Detection itself becomes impossible.

  Therefore, in a situation where a thin sheet-like foreign object is sandwiched, induction heating is performed without any problem and the temperature detection means functions normally. There is a problem that it cannot be recognized.

  In addition, the method of detecting the temperature based on the change of the control set value also knows only the relative value of the amount of change in temperature although the change in temperature is known, so overheating cannot be detected correctly when heating is started from a high temperature state. It had the problem that.

  The present invention solves the above-mentioned conventional problems, and controls the control set value of the high-frequency power supply means to maintain the set power instructed by the user, and the change of the control set value made by itself is nonmagnetic. An object of the present invention is to provide an induction heating cooker having a function of recognizing the state of overheating by monitoring the degree of demagnetization of the object to be heated that is observed by the degree of determination means and overheating.

  In order to solve the conventional problem, the induction heating cooker of the present invention controls the control set value of the high-frequency power supply means to maintain the set power instructed by the user, and the control set value performed by itself. The non-magnetization degree determining means observes the change in the temperature and monitors the non-magnetization degree of the object to be heated caused by overheating, thereby recognizing the state of overheating, so that an object is placed between the object to be heated and the heating coil. It is possible to provide an induction heating cooker having a function of recognizing overheating by capturing a characteristic physical phenomenon that occurs due to overheating even in a situation where there is a pinch.

  In addition, when setting power is input to an object to which high-frequency power is difficult to be supplied by performing control that can approximate the resonance frequency unique to the object to be heated using the operating frequency of the high-frequency power supply means as a control setting value In addition, the non-magnetization degree determination means captures the change in which the operating frequency change for maintaining the set power changes from falling to rising due to overheating of the heated surface of the object to be heated and demagnetizing, thereby making an overheating determination. An induction heating cooker having a function to perform can be provided.

  Also, when the energizing time of the high-frequency power supply means is used as the control set value, and control is performed at a fixed frequency at which interference noise does not easily occur, the set power is maintained by overheating the heated surface of the object to be heated and demagnetizing it. Therefore, it is possible to provide an induction heating cooker having a function of making an overheating determination when the non-magnetization degree determining means captures a change in energization time from rising to falling.

  In addition, a boosting means is provided, and the boosting ratio of the voltage supplied from the boosting means to the high-frequency power supply means is used as a control set value, and the high-frequency power supply means is set to a high voltage to be used for power supply. When heating corresponding to an object to be heated that is difficult to supply, the heating surface of the object to be heated becomes overheated and demagnetized, so that the change in the step-up ratio from rising to falling to maintain the set power is nonmagnetic. It is possible to provide an induction heating cooker having a function of performing overheating determination by capturing the chemical degree determination means.

  In addition, when the non-magnetization degree determining means determines that overheating is applied, the heating is stopped by the control set value changing means, so that the heated object such as a pan is prevented from being deformed or burnt due to emptying. An induction heating cooker having a function can be provided.

  In addition, when the non-magnetization degree determining means determines that overheating, the control target value power is made smaller than the set power by the control set value changing means, so that the food is cooked in a state where overheating is suppressed without stopping cooking. It is possible to provide an induction heating cooker having a function of waiting for input.

  In addition, it is provided with cooked object detection means for detecting that the object to be cooked is input by observing the change of the control set value changing means, and the non-magnetization degree determination means performs overheating determination and temporarily sets power from It is possible to provide an induction heating cooker having a function of returning the lowered control target power to the original set power when the food input is detected by the food input detecting means.

  In addition, a menu setting means is provided, and in the case where the set menu is a cooking method in which the food to be cooked is added after preheating such as grilled food or fried food, the control target power is set by overheating determination by the non-magnetization degree determining means It is possible to provide an induction heating cooker having a function of waiting for an object to be heated while reducing overheating and suppressing overheating, and a function of performing heating control according to a menu.

  In addition, in the case of a cooking method in which a menu setting means is provided and the set menu is a cooking method in which cooking is performed such as a water heater, heating is stopped by overheating determination by the non-magnetization degree determination means, Thus, it is possible to provide an induction heating cooker having a function of preventing a heated object such as a pan from being deformed or scorching and having a function of performing heating control in accordance with a menu.

  Moreover, the induction heating cooker provided with the alerting | reporting means and provided with the function to inform a user that the non-magnetization degree determination means performed overheating detection can be provided.

  In addition, it has a temperature measurement means, and by detecting overheating by using both the non-magnetization degree determination means and the temperature measurement means, it has a function of detecting overheating even when it is not overheating that causes demagnetization. An induction heating cooker provided can be provided.

The induction heating cooker of the present invention controls the control set value of the high-frequency power supply means to maintain the set power instructed by the user, and the non-magnetization degree determination means determines the change of the control set value performed by itself. By observing and recognizing the state of overheating by monitoring the degree of demagnetization of the object to be heated caused by overheating, the object that hinders the overheating detection operation of the temperature detection means is detected between the object to be heated and the heating coil. It is possible to provide an induction heating cooker having a function of recognizing overheating by capturing a characteristic change in a control set value caused by overheating even in a situation where it is sandwiched between them.

The block diagram which shows the structure of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the correlation of the operating frequency of the induction heating cooking appliance and input power in Embodiment 1 of this invention. The figure which shows the temperature characteristic of the equivalent series resistance and equivalent series inductance of the to-be-heated material comprised with the magnetic stainless steel of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the setting power maintenance operation | movement at the time of using an operating frequency for the control setting value of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the setting electric power maintenance operation | movement at the time of using energization time or a pressure | voltage rise ratio for the control setting value of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the change at the time of demagnetization generation | occurrence | production at the time of using an operating frequency for the control setting value of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the change at the time of demagnetization generation | occurrence | production at the time of using electricity supply time or a pressure | voltage rise ratio for the control setting value of the induction heating cooking appliance in Embodiment 1 of this invention. The block diagram of the induction heating cooking appliance in Embodiment 2 of this invention The figure which shows the control set value change of the induction heating cooking appliance in Embodiment 2 of this invention The block diagram of the induction heating cooking appliance in Embodiment 3 of this invention Block diagram showing the configuration of a conventional induction heating cooker

  1st invention, the to-be-heated object for putting a to-be-cooked object, the heating coil for heating a to-be-heated object, the high frequency electric power supply means for inject | pouring high frequency electric power into a to-be-heated object through a heating coil, Power detection means for observing the high-frequency power supplied by the high-frequency power supply means, and a control setting value of the high-frequency power supply means so as to maintain the power set by the user following the impedance change due to the temperature rise of the object to be heated. Control set value changing means for changing the setting value, and non-magnetization degree determining means for detecting overheating by monitoring the set value change of the control set value changing means and determining the degree of demagnetization of the object to be heated. Therefore, in order to maintain the set power instructed by the user, the control set value of the high-frequency power supply means is controlled, and the non-magnetization degree determining means observes the change in the control set value performed by itself, By monitoring the degree of demagnetization of the object to be heated caused by heat, it is possible to recognize the situation of overheating, so that the characteristic that occurs due to overheating even when the object is sandwiched between the object to be heated and the heating coil An induction heating cooker having a function of recognizing overheating by capturing various physical phenomena can be provided.

  In particular, the second invention uses the operating frequency of the high-frequency power supply means as the control set value in the first invention, and the heating surface of the object to be heated becomes overheated and demagnetized, thereby maintaining the set power. For this reason, the non-magnetization degree determining means captures the change in which the operating frequency change changes from falling to rising, thereby making an overheating determination, and using the operating frequency of the high-frequency power supply means as the control set value When setting power is applied to an object to be heated that is difficult to supply high-frequency power by performing control that can approach the natural resonance frequency, the heating surface of the object to be heated becomes overheated and becomes non-magnetic. To provide an induction heating cooker having a function of making an overheating determination by a non-magnetization degree determination means capturing a change in which an operating frequency change from a decrease to an increase in order to maintain power It can be.

In particular, the third invention uses the energizing time of the high-frequency power supply means as the control set value in the first invention, and maintains the set power by heating the heated surface of the object to be heated and demagnetizing. For this reason, the non-magnetization degree determination means captures the change in the energization time from rising to lowering, thereby making an overheating determination, using the energization time of the high-frequency power supply means as a control set value, and generating interference noise. When the control is performed at a fixed frequency that is difficult to perform, the non-magnetization degree determination means detects the change in the energization time from rising to falling to maintain the set power by overheating the heated surface of the object to be heated and demagnetizing. It is possible to provide an induction heating cooker having a function of performing overheating determination by grasping.

  In particular, the fourth aspect of the invention includes the step-up means in the first aspect, uses the step-up ratio of the voltage supplied from the step-up means to the high-frequency power supply means as the control set value, and the heating surface of the object to be heated is overheated By making the non-magnetization, the non-magnetization degree judgment means captures the change in the step-up ratio from rising to lowering in order to maintain the set power. When heating corresponding to an object to be heated that is difficult to supply high-frequency power is performed by setting the voltage used by the high-frequency power supply means to be high by using the step-up ratio of the means, the heating surface of the object to be heated is By overheating and demagnetizing, the non-magnetization degree judgment means captures the change in the step-up ratio from rising to falling to maintain the set power, and the induction heating control with the function to make overheating judgment It is possible to provide a vessel.

  In the fifth invention, in particular, in any one of the first to fourth inventions, when the non-magnetization degree determining means determines that the heating is overheated, the control setting value changing means stops heating, so that Thus, it is possible to provide an induction heating cooker having a function of preventing a heated object such as a pan from being deformed or burnt.

  In a sixth aspect of the invention, in particular, when the non-magnetization degree determining means determines overheating in any one of the first to fourth aspects of the invention, the control set value changing means makes the control target power smaller than the set power. Thereby, the induction heating cooking appliance provided with the function to wait for input of a to-be-cooked object etc. in the state which suppressed overheating, without stopping cooking can be provided.

  In particular, the seventh aspect of the present invention includes cooking object input detecting means for detecting that the cooking object has been input by observing a change in the control setting value by the control setting value changing means in the sixth invention. When the object to be cooked is detected, the control target power, which has been smaller than the set power, is restored to the original set power. An induction heating cooker having a function of automatically returning to the set power can be provided.

  In an eighth aspect of the invention, in particular, in the sixth or seventh aspect of the invention, the menu setting means is provided, and the set menu is not the above-described cooking method in which the food to be cooked is input after preheating such as grilled food or fried food. An induction heating cooker having a function of performing heating control in accordance with the menu can be provided by lowering the control target power from the set power by the overheating determination by the degree of magnetization determination means.

  The ninth invention includes the menu setting means in the fifth invention, and in the case of a cooking method in which the set menu is heated in a state where an object is to be cooked such as a kettle, the non-magnetization degree determining means is used. By stopping heating by overheating determination, an induction heating cooker having a function of performing heating control according to the menu can be provided.

  In a tenth aspect of the invention, in particular, in any one of the first to ninth aspects, induction heating cooking is provided, which has a function of notifying the user that the non-magnetization degree determination means has detected overheating. Can be provided.

An eleventh aspect of the invention is an induction heating cooker that includes a temperature measurement unit in any one of the first to tenth aspects of the invention and performs overheating detection by using a non-magnetization degree determination unit and a temperature measurement unit in combination. Thus, an induction heating cooker having a function of detecting overheating can be provided even when it is not overheating enough to cause demagnetization.

  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 shows a block diagram of an induction heating cooker according to the first embodiment of the present invention.

  In FIG. 1, the object to be cooked 101, the object to be heated 102, the heating coil 103, the high frequency power supply means 104, the power detection means 105, the switching element 106, the resonance capacitor 107, the control means 108, the control set value change means 109, nonmagnetic The degree determination unit 110, the power source 111, the booster unit 112, the notification unit 113, and the menu setting unit 114 are included.

  The heated object 102 is a pan, the control means 108, the control set value changing means 109, the non-magnetization degree determining means 110 is a microcomputer, the boosting means 112 is a boost converter, the notifying means 113 is a liquid crystal display means, This configuration can be easily realized by using switch means connected to the microcomputer as the menu setting means 114.

  In FIG. 1, a power source 111 supplies a DC power source obtained by converting a commercial single-phase 100 V or 200 V AC power source into a DC by a diode bridge as input power to the high-frequency power supply means 104.

  In general, the power source of the high-frequency power supply unit 104 is often a power source 111 boosted by a boost unit 112 such as a boost converter, but is not limited thereto.

  By boosting the voltage of the power supply 111, it is possible to reduce the current when supplying the same power to the high-frequency power supply means 104. Therefore, the component rating of each component constituting the high-frequency power supply means 104 is lowered. Therefore, it is desirable to increase the voltage of the power supply because it is possible to reduce the size and cost of the components and to provide a benefit to the user by making the product cheaper and smaller.

  The high frequency power supply means 104 constitutes a resonance circuit by connecting a switching element 106 and a resonance capacitor 107 which are constituent elements to a heating coil 103 magnetically coupled to the object to be heated 102. The resonance circuit configured here operates to supply the high-frequency current to the heating coil 103 by switching the current path of the power supplied from the power source 111 and the booster 112 by the switching element 106.

  At this time, a high-frequency magnetic field is generated from the heating coil 103 and magnetic flux passes through the magnetically coupled metal of the object to be heated 102, so that eddy current due to electromagnetic induction flows to the object to be heated 102, and its Joule heat Therefore, the object to be heated 102 is heated.

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

  The control set value changing operation performed by the control set value changing unit 109 to maintain the set power instructed by the user from the high frequency power supply unit 104 will be described.

In the heating control of the induction heating cooker, the control means 108 controls the control set value changing means so that the input power obtained by the power detection means 105 is substantially the same as the set power instructed by the user of the induction heating cooker. This is done by giving an instruction to 109 and adjusting the energizing time and operating frequency of the switching element 106, the boosting ratio of the boosting means 112, and the input voltage of the resonant capacitor 107.

  First, the reason why the control set value needs to be changed by heating the article to be heated 102 will be described with reference to FIG. FIG. 2 is a diagram showing the correlation between the operating frequency of the induction heating cooker and the input power in the first embodiment of the present invention, and the correlation between the operating frequency of the switching element 106 constituting the high-frequency power supply means 104 and the input power. Is shown.

In FIG. 2, the solid line indicates the correlation when the object to be heated 102 is at a low temperature, and the broken line indicates the correlation when the object to be heated 102 is at a high temperature. Here, in induction heating, the object to be heated 102 and the heating coil 103 are magnetically coupled to function as an equivalent series resistance (denoted as Rs) and an equivalent series inductance (denoted as Ls) in the high-frequency power supply means 104. However, a physical phenomenon (FIG. 3) in which Ls and Rs increase in proportion to the temperature rise of the object to be heated 102 and the input power characteristic change in FIG. 2 occurs. FIG. 3 is a diagram showing the temperature characteristics of the equivalent series resistance and equivalent series inductance of a heated object made of magnetic stainless steel of the induction heating cooker according to the first embodiment of the present invention.
That is, when the temperature increases and Ls increases, the input power characteristic slides leftward on the graph of FIG. 2, and when Rs increases, the input power characteristic slides downward on the graph of FIG.

  Due to this change, the object to be heated 102 is heated by the high frequency power supply means 104 through the heating coil 103 and the temperature of the object to be heated 102 rises, whereby the correlation between the operating frequency of the switching element 106 and the input power is obtained. 2 gradually changes from (low temperature) to (high temperature) in FIG.

  Therefore, in order to maintain the set power instructed by the user, the control means 108 uses the control set value changing means 109 to detect the power detection means 105 indicating the power supplied by the high-frequency power supply means 104. An operation for changing the control set value in accordance with the input power characteristic is required so that the power is approximately the same as the input power set by the user.

  Here, when the operating frequency of the switching element 106 constituting the high-frequency power supply means 104 is used as the control set value to be changed for maintaining the set power, as shown in FIG. The power is maintained by changing the operating frequency. FIG. 4 is a diagram showing a set power maintaining operation when an operating frequency is used as the control set value of the induction heating cooker in the first embodiment of the present invention. (A) shows the change when demagnetization does not occur, and (b) shows the change when demagnetization occurs.

  When the control set value to be changed is set as the operating frequency, it is not necessary to change the input power characteristic itself, so that the set power can be maintained in a wide range. On the other hand, there is a possibility that an audible interference sound is generated by changing the frequency.

  FIG. 5 is a diagram illustrating a set power maintaining operation when the energization time or the step-up ratio is used as the control set value of the induction heating cooker according to the first embodiment of the present invention. (A) shows the change when demagnetization does not occur, and (b) shows the change when demagnetization occurs.

When the energizing time of the switching element 106 constituting the high frequency power supply means 104 or the step-up ratio of the step-up means 112 is used as the control set value to be changed for maintaining the set power, as shown in FIG. In order to compensate for the input power that has decreased due to the input power characteristics, the energization time within the same switching cycle is increased, or the voltage applied at the same energization time is increased by increasing the boost ratio of the booster 112. Thus, by increasing the power injected from the power supply 111, the input power characteristic itself is changed to maintain the power.

  Next, a description will be given of a method in which the demagnetization degree determination means 110, which is the main object of the present invention, determines overheating by the demagnetization determination. The operation of supplying high-frequency power to the object to be heated 102 through the heating coil 103 by the high-frequency power supply means 104 is performed by generating a high-frequency eddy current in the object to be heated 102.

  Here, when a high-frequency current flows through the conductor, a skin effect occurs in which the current density is high on the surface of the conductor and becomes low when the conductor is separated from the surface. Therefore, the eddy current flowing through the object to be heated 102 Concentrate on thin parts.

  If the object to be heated 102 is heated with high power in an empty state without a load, and the state in which more energy is supplied than the temperature dispersion due to heat conduction or radiation continues, the heating surface on which the heating power is concentrated is very hot. The magnetic metal reaches the Curie point at which it loses magnetism.

  Since the heated surface of the object to be heated 102 that has reached the Curie point loses its magnetism, the equivalent series inductance Ls that is exhibited when the object to be heated 102 and the heating coil 103 are magnetically coupled is increased in temperature. Will decrease. The non-magnetization degree determination means 110 detects overheating by capturing a characteristic change in the control set value due to demagnetization of the heated surface of the article to be heated 102 that occurs for the reason described above. FIG. 6 is a diagram showing a change when demagnetization occurs when the operating frequency is used as the control set value of the induction heating cooker according to the first embodiment of the present invention.

  When the operating frequency is used for the control set value, the non-magnetization degree determining means 110 confirms the change in the control set value during the set power maintaining operation by the control set value changing means 109 as shown in FIG. After reaching the power, the control set value continues to decrease, and passes through the lowest point to reach a predetermined value (for example, ((the control set value when the set power is reached) − (the control set value at the lowest point)) / 5) By confirming the further rising operation, the degree of demagnetization of the article to be heated 102 can be determined and the overheating determination can be performed.

  When it is determined that the state is an overheating state, the demagnetization degree determination unit 110 notifies the control unit 108, and the control unit 108 stops heating according to the operation setting when the overheating determination is instructed in advance by the user. Alternatively, the control set value changing unit 109 is instructed to set the control target power to a value lower than a predetermined set power (for example, 500 W), and the control operation performed in response to the overheating determination using the notification unit 113 is performed. Notify the user.

  Here, the operation setting at the time of overheating determination can also be input by selecting the cooking by the menu setting means 114, and the cooking method such as grilled food or stir-fried food to which the cooking object 101 is charged after preheating is used. In the case of a cooking method such as boiling water or heating a cooked food in which the control target value is lowered from the set power by overheating judgment by the non-magnetization degree judging means 110 and the cooked food 101 is put in, it is non-magnetic. It becomes operation | movement which stops heating by the overheating determination by the chemical degree determination means 110. FIG. FIG. 7 is a diagram illustrating a change when demagnetization occurs when the energization time or the step-up ratio is used as the control set value of the induction heating cooker according to the first embodiment of the present invention.

  When the energization time or the step-up ratio is used as the control set value, the non-magnetization degree determination means 110 confirms the change in the control set value during the set power maintenance operation by the control set value change means 109 as shown in FIG. Then, after reaching the set power, the control set value continues to rise and passes through the highest point to reach a predetermined value (for example, ((control set value at the highest point) − (control set value when the set power is reached)) / 5. ) By confirming the lowering operation, it is possible to determine the degree of demagnetization of the article to be heated 102 and perform overheating determination.

  When it is determined that the state is an overheating state, the non-magnetization degree determination unit 110 notifies the control unit 108, and the control unit 108 determines the heating stop or the control target power in advance according to the setting instructed by the user in advance. The control setting value changing unit 109 is instructed to set a value lower than the set power (for example, 500 W), and the control operation performed in response to the overheating determination using the notification unit 113 is notified to the user.

  Here, the operation setting at the time of overheating determination can also be input by selecting the cooking by the menu setting means 114, and the cooking method such as grilled food or stir-fried food to which the cooking object 101 is charged after preheating is used. In the case of a cooking method such as boiling water or heating a cooked food in which the control target value is lowered from the set power by overheating judgment by the non-magnetization degree judging means 110 and the cooked food 101 is put in, it is non-magnetic. It becomes operation | movement which stops heating by the overheating determination by the chemical degree determination means 110. FIG.

  As described above, in this embodiment, the control setting value changing unit 109 changes the control setting value of the high-frequency power supply unit 104 in order to maintain the setting power instructed by the user, and the control setting performed by itself. The non-magnetization degree determination means 110 observes the change in value and recognizes the state of overheating by monitoring the degree of non-magnetization of the article to be heated 102 caused by overheating. Even in a situation where an object is sandwiched between 103, overheating can be recognized by capturing a characteristic physical phenomenon caused by overheating.

  In addition, when setting power is input to the object to be heated 102 that is difficult to supply high-frequency power by performing control using an operating frequency that can approach the resonance frequency unique to the object to be heated as a control set value, When the heating surface of the object 102 is overheated and becomes non-magnetic, the non-magnetization degree determination means 110 captures a change in which the operating frequency change for maintaining the set power changes from a decrease to an increase. it can.

  In addition, when the energizing time of the high-frequency power supply means 104 is used as a control set value and control is performed at a fixed frequency at which interference noise is unlikely to occur, the heating surface of the object to be heated 102 is overheated and becomes non-magnetic. It is possible to provide an induction heating cooker having a function of making an overheating determination when the non-magnetization degree determination unit captures a change in energization time from rising to falling to maintain power.

  Moreover, it is difficult to supply high-frequency power by using a boost ratio of the voltage supplied from the booster 112 to the high-frequency power supply unit 104 as a control set value and setting the voltage used by the high-frequency power supply unit 104 to supply power to a high value. When heating corresponding to the object to be heated 102 is performed, the heating surface of the object to be heated 102 is overheated and demagnetized, thereby demagnetizing the change in the step-up ratio from increasing to decreasing to maintain the set power. The overheating determination can be performed by the degree determination means 110.

  In addition, when the non-magnetization degree determination means 110 determines that the heating is overheated, the heating is stopped by the control set value changing means, thereby preventing the heated object such as the pan from being deformed or burnt by emptying. can do.

  Further, when the non-magnetization degree determining means 110 determines that overheating is applied, the control set value changing means 109 makes the control target power smaller than the set power so that the overheating is suppressed without stopping cooking. We can wait for input such as cooking.

  If the menu set by the user using the menu setting unit 114 is a cooking method in which the food to be cooked is added after preheating such as grilled food or fried food, control is performed by overheating determination by the non-magnetization degree determining unit 110. The target power can be reduced below the set power.

  When the menu set by the user using the menu setting unit 114 is a cooking method in which heating is performed in a state in which an object is to be cooked such as a water heater, heating is stopped by overheating determination by the non-magnetization degree determination unit 110. be able to.

  In addition, the notification means 113 can inform the user that the non-magnetization degree determination means 110 has detected overheating and has performed control to stop heating or reduce the control target power.

  In the present embodiment, the high frequency power supply means 104 has been described using the SEPP inverter circuit form, but it goes without saying that the high frequency power supply means 104 does not depend on the inverter circuit form.

(Embodiment 2)
FIG. 8 shows a block diagram of an induction heating cooker in the second embodiment of the present invention. In FIG. 8, reference numeral 801 denotes a cooking object input detecting means, and this configuration can be easily realized by using a microcomputer.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In the drawings, the same reference numerals are given to portions showing the same operations as those in the first embodiment.

  The basic operation of the induction heating cooker in the second embodiment is the same as that in the first embodiment. In the second embodiment, after the non-magnetization degree determination unit 110 performs overheating determination based on the degree of demagnetization of the object to be heated 102, the control set value change unit 109 maintains the control target power by the high-frequency power supply unit 104. Unlike the first embodiment, the to-be-cooked object input detecting means 801 detects the input of the object to be heated 102 during the operation.

  FIG. 9A is a diagram showing a change in the control set value when the object to be heated 102 is input when the operating frequency is used as the control set value. FIG. 9B is a diagram showing the control set value using the energization time or the step-up ratio. It is a figure which shows the control set value change when the to-be-heated material 102 is thrown in in the case.

  As shown in FIG. 9, when the object to be cooked 102 is thrown in from an empty-boiled state or a state in which the control target value is decreasing, heat energy is rapidly taken away from the object to be heated 102, so that the heating surface temperature of the object to be heated 102 rapidly increases. A sudden change in the control set value occurs due to a drop in the value.

  The to-be-cooked input detecting means 801 observes the control set value change periodically (for example, every second), and the absolute value of the control set value change rapidly changes (for example, ((previous control set value) − (current control)). By detecting the phenomenon that the absolute value of the set value)) is ½ or more of the control set value change width), the input of the object to be heated 102 is detected.

  When the to-be-cooked input detecting means 801 detects the input of the to-be-cooked object 101, it notifies the control means 108, and the control means 108 instructs the control set value changing means 109 to return the control target power to the original set power. To do.

  As described above, in the present embodiment, it is provided with the cooked object input detecting means for detecting that the object to be cooked 101 is input by observing the change of the control set value by the control set value changing means 109, When the input of the object to be cooked 101 is detected, the control target power that has been smaller than the set power can be restored to the original set power.

(Embodiment 3)
FIG. 10 shows a block diagram of an induction heating cooker in the third embodiment of the present invention. In FIG. 10, reference numeral 1001 denotes a temperature detecting means, and this configuration can be easily realized by using a thermistor.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In FIG. 10, the same reference numerals are given to portions showing the same operations as those in the first embodiment.

  The basic operation of the induction heating cooker in the third embodiment is the same as that in the first embodiment. The third embodiment is different in that the temperature detecting means 1001 detects the temperature of the object to be heated 102.

  After the heating is started, the control unit 108 detects the temperature of the object to be heated 102 using the temperature detection unit 1001 in parallel with the overheating determination by the demagnetization degree determination unit 110.

  The temperature detection means 1001 cannot detect the temperature of the object to be heated 102 in a situation where an object is sandwiched between the object to be heated 102 and the heating coil 103, and the observation part of the object to be heated 102 is not the hottest. Although there are drawbacks such as possibility and time-consuming follow-up, it works effectively against overheating that is not so demagnetized.

  Therefore, in a heating state where the set power is large and the overheating proceeds rapidly so that demagnetization occurs, the nonmagnetization degree determination means 110 is mainly responsible for overheating detection and takes time (for example, 2 minutes or more). When overheating proceeds, the temperature detection means is mainly responsible for overheating detection.

  When the temperature of the object to be heated 102 by the temperature detection means 1001 reaches a predetermined temperature (for example, 300 ° C.), the control means 108 sets heating stop or control target power in advance according to the setting instructed by the user in advance. The control setting value changing unit 109 is instructed to set a value lower than the set power (for example, 500 W), and the control operation performed in response to the overheating determination using the notification unit 113 is notified to the user.

  Here, the operation setting at the time of overheating determination can also be input by selecting the cooking by the menu setting means 114, and the cooking method such as grilled food or stir-fried food to which the cooking object 101 is charged after preheating is used. In the case of a cooking method such as boiling water or heating a cooked food in which the control target value is lowered from the set power by overheating judgment by the non-magnetization degree judging means 110 and the cooked food 101 is put in, it is non-magnetic. It becomes operation | movement which stops heating by the overheating determination by the chemical degree determination means 110. FIG.

  As described above, in the present embodiment, the overheating detection is performed by using the non-magnetization degree determination unit 110 and the temperature measurement unit 1001 in combination, so that even if the overheating is not so high that demagnetization occurs. Heating can be detected.

  As described above, the induction heating cooker according to the present invention controls the control setting value of the high-frequency power supply means in order to maintain the set power instructed by the user, and the change of the control setting value performed by itself is not An object that obstructs the overheating detection operation of the temperature detecting means is detected by recognizing the state of overheating by observing the degree of demagnetization and monitoring the degree of demagnetization of the object to be heated caused by overheating. Even in a situation where it is sandwiched between a heated object and a heating coil, overheating can be recognized by capturing the characteristic change in the control setting value caused by overheating, so not only induction heating cookers, The present invention can be widely applied to the use of equipment for heating an object to be heated while confirming overheating of the object to be heated by a temperature detecting means.

DESCRIPTION OF SYMBOLS 101 To-be-cooked object 102 To-be-heated object 103 Heating coil 104 High frequency electric power supply means 105 Electric power detection means 109 Control setting value change means 110 Non-magnetization degree determination means 113 Notification means 114 Menu setting means 801 Cooking object input detection means 1001 Temperature detection means

Claims (11)

An object to be cooked, a heating coil for heating the object to be cooked, a high-frequency power supply means for injecting high-frequency power into the object to be heated through the heating coil, and the high-frequency power supply means A power detection means for observing the high-frequency power to be supplied, and a control setting value for changing the control setting value of the high-frequency power supply means so as to follow the impedance change due to the temperature rise of the object to be heated and maintain the power set by the user An induction heating cooker provided with a change means and a non-magnetization degree determination means for detecting overheating by monitoring a set value change of the control set value change means and determining a non-magnetization degree of the object to be heated. The operating frequency of the high-frequency power supply means is used as the control set value, and the heating surface of the object to be heated is overheated and demagnetized, so that the operating frequency changes from falling to rising to maintain the set power. The induction heating cooker according to claim 1, wherein the overheating determination is performed by the non-magnetization degree determination means. The energization time of the high-frequency power supply means is used as the control set value, and the heating surface of the object to be heated is overheated and demagnetized, thereby changing the energization time from rising to falling to maintain the set power. The induction heating cooker according to claim 1, wherein the overheating determination is performed by the non-magnetization degree determination means. A boosting means is provided, and the set power is maintained by using the boost ratio of the voltage supplied from the boosting means to the high-frequency power supply means as the control set value, and the heated surface of the object to be heated is overheated and demagnetized. The induction heating cooker according to claim 1, wherein the non-magnetization degree determination means makes an overheating determination by capturing a change in which the step-up ratio changes from an increase to a decrease for the purpose. The induction heating cooker according to any one of claims 1 to 4, wherein when the non-magnetization degree determining means determines that the heating is overheating, the control set value changing means stops heating. The induction heating cooker according to any one of claims 1 to 4, wherein when the non-magnetization degree determining means determines that the heating is overheating, the control set value changing means makes the control target power smaller than a set power. The apparatus includes cooking object input detecting means for detecting that the object to be cooked is input by observing a change in the control setting value by the control setting value changing means, and when the input of the object to be cooked is detected, the electric power is set lower than the set power. The induction heating cooker according to claim 6, wherein the control target power that has been restored is restored to the original set power. In the case of a cooking method in which the menu is set and the set menu is a cooking method in which the food to be cooked is added after preheating such as grilled or fried food, the control target power is set by overheating determination by the non-magnetization degree determining means The induction heating cooker according to claim 6 or 7, which is further reduced. 6. The method according to claim 5, further comprising a menu setting unit, wherein when the set menu is a cooking method in which heating is performed in a state in which an object is to be cooked such as a kettle, heating is stopped by overheating determination by the non-magnetization degree determination unit. Induction heating cooker. The induction heating cooker according to any one of claims 1 to 9, further comprising a notification unit and a function of reporting to the user that the non-magnetization degree determination unit has detected overheating. The induction heating cooker according to any one of claims 1 to 10, further comprising a temperature measuring unit, wherein overheating detection is performed using the non-magnetization degree determining unit and the temperature measuring unit in combination.

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