JP5590987B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker, and more particularly to improvement of cooking accuracy and safety ensuring by a temperature sensor.

  Conventionally, in an induction heating apparatus, a means using a thermistor (hereinafter also referred to as a contact-type temperature sensor) as a means for measuring the temperature of a cooking container (hereinafter also referred to as an object to be heated), or There is a combination of a thermistor and an infrared sensor. As a combination of a thermistor and an infrared sensor, the temperature detection means converts the temperature of the object to be heated from the energy received by the thermistor and infrared sensor, and if the temperature gradient of the object to be heated is greater than the specified value, the infrared sensor Thermistor temperature is prioritized when the output is lower than the specified value, and the heating power is suppressed or stopped when the temperature of the object to be heated detected by the infrared sensor changes above a predetermined gradient. By doing, the ignition of oil and the red heat and deformation of the pan were prevented (for example, refer to Patent Document 1).

JP 2008-41471 A (pages 1 to 3 and page 7)

In the conventional induction heating cooker described in Patent Document 1, the temperature detection means converts the temperature of the object to be heated from the output signal of the thermistor and the energy received by the infrared sensor as described above, and the temperature of the object to be heated is calculated. If the gradient of temperature rise in a given time is greater than a given value, priority is given to the output of the infrared sensor. For example, a heated object such as a frying pan that has already been heated and heated to a given temperature. If the high frequency power is supplied to the heating coil in an attempt to start cooking by placing it on the top plate, the object to be heated is further heated by induction to become overheated. Nevertheless, if the window of the infrared sensor is dirty, the temperature detection accuracy decreases due to the window contamination of the infrared sensor.
However, depending on the degree of dirt on the window of the infrared sensor, the follow-up speed is slow but an accurate contact-type temperature sensor may be given priority instead of a high-accuracy contact-type temperature sensor. Since the detection accuracy of the temperature rise gradient is also lowered due to window contamination, there is a problem of erroneous detection.
In such a case, the contact temperature sensor (thermistor) can detect the dangerous temperature more accurately than the infrared sensor. Therefore, based on both outputs, priority is given to either one of the objects to be heated. Judging the temperature is more accurate and desirable.

  The present invention has been made to solve such problems, and the purpose thereof is to improve the accuracy of cooking of a heated object by effectively utilizing both a contact temperature sensor and an infrared sensor. Another object of the present invention is to provide an induction heating cooker that can prevent an object to be heated from being overheated.

An induction heating cooker according to the present invention includes a top plate on which an object to be heated is placed, a heating coil that is disposed below the top plate and induction-heats the object to be heated, and supplies AC power to the heating coil. an inverter circuit, a contact-type temperature sensor in contact with the back surface of the top plate to detect the heat of the object to be heated, an infrared sensor for detecting infrared rays of the heated object, the output of the output and the infrared sensor of the contact type temperature sensor Temperature detecting means for converting into temperature and control means for controlling the inverter circuit. The control means controls the inverter circuit to perform induction heating by the heating coil, and outputs the output of the contact temperature sensor to the temperature detecting means. The gradient of the first temperature rise of the object to be heated is calculated based on the temperature converted by, and the second temperature rise of the object to be heated is calculated based on the temperature converted from the output of the infrared sensor by the temperature detecting means. Calculating a gradient, when at least one of the gradient or slope of the second temperature increase in the first temperature rise is above a predetermined value, the supply power amount of the inverter circuit to the heating coil suppressed or stopped, When the gradient of the first temperature rise and the gradient of the second temperature rise do not exceed a predetermined value, the time counting means for increasing the amount of power supplied to the inverter circuit to the heating coil and counting the elapsed time from the start of cooking And the control means calculates the first temperature rise and the second temperature rise on the basis of the output of the temperature detection means every time when the time obtained from the time measuring means elapses a predetermined time. When the rise and the second temperature rise are within the predetermined range, it is determined that the object to be heated has boiled, and the first temperature rise and the second temperature rise are compared, and there is a difference exceeding the predetermined value. No if detected One precision those judged to have deteriorated or.

  According to the present invention, at least one of the first temperature rise of the heated object calculated based on the output of the contact temperature sensor and the second temperature rise of the heated object calculated based on the output of the infrared sensor. Is larger than a predetermined value, the control means automatically suppresses or stops the amount of power supplied to the heating coil, so that the accuracy of cooking of the heated object is improved and the heated object is overheated. Can be prevented beforehand.

It is a perspective view which shows the external appearance of the induction heating cooking appliance which concerns on this invention. It is a block diagram which shows the structure of the control system in Embodiment 1 of the induction heating cooking appliance which concerns on this invention. It is a flowchart which shows the main process of the control means 6 in Embodiment 1 of the induction heating cooking appliance which concerns on this invention. It is a flowchart which shows the heating cooking process of the control means 6 in Embodiment 1 of the induction heating cooking appliance which concerns on this invention. It is a block diagram which shows the structure of the control system in Embodiment 2 of the induction heating cooking appliance which concerns on this invention. It is a flowchart which shows the heating cooking process of the control means 6 in Embodiment 2 of the induction heating cooking appliance which concerns on this invention. It is a flowchart which shows the heating cooking process of the control means 6 in Embodiment 3 of the induction heating cooking appliance which concerns on this invention. It is another flowchart which shows the heating cooking process of the control means 6 in Embodiment 3 of the induction heating cooking appliance which concerns on this invention.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing the appearance of an induction heating cooker according to the present invention, and FIG. 2 is a block diagram showing the configuration of a control system in Embodiment 1 of the induction heating cooker according to the present invention.
As shown in FIG. 1, the induction heating cooker 100 includes a main body 1 and a heat-resistant glass top plate 2 on which an upper surface of the main body 1 is formed and a heated object such as a pan or a frying pan is placed. A heating part mark 3 indicating the positions of three heating parts for induction heating of the object to be heated is disposed below the top plate 2. Specifically, a heating part mark 3a on the left side, a heating part mark 3b on the right side, and a heating part mark 3c on the rear side are arranged as viewed from the front (from arrow A in FIG. 1).
A heating coil 4 is disposed below the top plate 2 so as to correspond to each of the three heating unit marks 3 on the top plate 2. That is, the heating coil 4a is disposed directly below the heating part mark 3a, the heating coil 4b is disposed directly below the heating part mark 3b, and the heating coil 4c is disposed directly below the heating part mark 3c.

  As shown in FIG. 2, the main body 1 has an inverter circuit 5 for supplying high-frequency power to the heating coils 4a, 4b and 4c, a control means 6 for controlling the inverter circuit 5, and a time measuring means 7 for calculating time. Is mounted in a state of being accommodated in a substrate case (not shown). The control means 6 is constituted by a microcomputer, a DSP, a microprocessor, etc., and has a storage means (not shown) built therein. The installation location of the printed circuit board may be anywhere as long as it is far from the heat generation location and in the coolable air path, but it is preferably arranged upstream of the heating coil 4 from the viewpoint of cooling efficiency. Although not described in detail because it is not related to the present invention, cooling fans (not shown) are installed on both sides of the lower back of the main body 1 to suck in air from the outside of the main body 1 and print circuit boards (see FIG. (Not shown) and cooling air are sent to the heating coil 4 to cool them, and then the process proceeds backward and is exhausted out of the cooker main body 1 through an exhaust port formed at the rear of the main body 1. As shown in FIG. 1, a grill 9 is provided at the lower portion of the main body 1 so that it can be pulled out, and cooking of grilled dishes such as fish is possible.

Further, an operation unit 8 as an operation means is provided on the right side of the lower part of the main body 1 as shown in FIG. 1, and the user operates the operation unit 8 to adjust the heating output and induction heating cooking. Operation / setting information such as settings on the instrument can be input. The operation unit 8 includes an operation unit for the grill 9.
In addition, although the three heating coils 4a, 4b, and 4c constitute a so-called three-neck heating unit, a radiant heater having substantially the same diameter may be disposed instead of the heating coil 4c.
Further, one or more contact-type temperature sensors 11 such as a thermistor are disposed on the back surface (the surface corresponding to the heating coil 4) in the area of the heating part mark 3 of the top plate 2. Further, below the top plate 2, an infrared sensor 12 is disposed for each heating unit so as to detect infrared energy radiated from the bottom of the article to be heated 10 through the top plate 2. Further, below the top plate 2 is provided temperature detecting means 13 for A / D converting the detection signal of the thermistor 11 and the infrared energy received by the infrared sensor 12 into the temperature of the object 10 to be heated. The converted temperature information is output to the control means 6.
The contact temperature sensor 11 may be referred to as TH. Similarly, the infrared sensor 12 may be referred to as IR.
In the present invention, the temperature detection means 13 inputs both the output of the contact temperature sensor and the output of the infrared sensor 12 and converts them into respective temperatures. However, only the output of the contact temperature sensor is converted into temperature. The temperature detection means for converting the temperature detection means and the temperature detection means for converting only the output of the infrared sensor 12 into the temperature may be provided separately.

FIG. 3 is a flowchart showing a main process of the control means 6 in the first embodiment of the induction heating cooker according to the present invention, and FIG. 4 shows the control means in the first embodiment of the induction heating cooker according to the present invention. It is a flowchart which shows the heating cooking process of 6.
Next, operation | movement of the control means 6 in this Embodiment 1 is demonstrated using FIGS.
When the user turns on a power switch (not shown) of the induction heating cooker 100, the control means 6 is activated. In the main process shown in FIG. 3, the control means 6 first performs an initial process such as clearing the counter held therein or setting an initial value (step S301), and then set by the user from the operation unit 8. Information is input (step S302). Next, the control means 6 checks whether or not the input setting information is a cooking start command (step S303). If not, the control means 6 returns to step S302 again after steps S306 and S307, and the same as above. The process is repeated until a cooking start command is input. In this input waiting state, when the user places the object to be heated 10 on the top board 2, subsequently sets the thermal power information and presses the cooking start switch, a cooking start command signal is generated from the operation unit 8. Input to the control means 6. When the cooking start command is input in step S303, the control means 6 controls the inverter circuit 5 based on the thermal power information in the setting information, and may be referred to as high-frequency power to the heating coil 4 (hereinafter referred to as heating power). ) Is started (step S304). Thereby, the cooking of the to-be-heated material 10 by induction heating is started. Next, the control means 6 starts the cooking process software (step S305), and then returns to step S302. Thereby, the cooking process shown in FIG. 4 starts operation.

In step S303, when a cooking start command is not input, the control means 6 calculates a predetermined time based on the time acquired from the time measuring means 7 (this time is obtained by adding an extra time to the cooking time required for the cooking). It is checked whether or not it has elapsed (step S306). When the predetermined time has elapsed, the control means 6 determines that the cooking for the cooking has been completed, stops the cooking software (step S308), controls the inverter circuit 5 and supplies heating power to the heating coil 4. Is stopped (step S309), and the process is terminated. In step S306, if the predetermined time for cooking is not yet elapsed, the control means 6 checks whether a cooking stop command has been input (step S307). If the cooking stop command is not input, the process returns to step S302 to continue the process. In step S307, when a cooking stop command is input, the control means 6 determines that the cooking has ended, stops the cooking software (step S308), and controls the inverter circuit 5 to control the heating power to the heating coil 4. Is stopped (step S309), and then the process is terminated.
This stop command signal is used when the user wants to urgently stop cooking for some reason, or when the user himself / herself stops heating when it is determined that cooking has ended. It is generated by operation and output to the control means 6.

Next, the operation of the cooking process shown in FIG. 4 will be described.
When the function of the main cooking process is activated, the control unit 6 first acquires the detection temperature of the contact temperature sensor 11 (TH) and the detection temperature of the infrared sensor 12 (IR) from the temperature detection unit 13 (step). S401). Next, the control means 6 compares the detected temperature of the contact temperature sensor 11 (TH) with a preset upper limit value (TH limit value) for the contact temperature sensor (step S402). For example, since the object to be heated 10 is too hot and dangerous, the inverter circuit 5 is controlled to stop the supply of the heating power to the heating coil 4 (that is, the heating power is set to zero) (step S403) It returns to step S402 and repeats the same process until the temperature of the to-be-heated material 10 becomes lower than an upper limit. Thereby, the temperature of the article 10 to be heated gradually decreases. In step S402, if the detection temperature of the contact temperature sensor 11 (TH) is not equal to or higher than the upper limit value, the control means 6 sets the detection temperature of the infrared sensor 12 (IR) to a preset upper limit value (IR limit for IR sensor). (Step S404), if it is equal to or higher than this upper limit value, the object to be heated 10 is too hot and dangerous, so the inverter circuit 5 is controlled to stop the supply of heating power to the heating coil 4 (ie, After the heating power is set to zero) (step S403), the process returns to step S402, and the same processing is repeated until the temperature of the article to be heated 10 becomes lower than the upper limit value. Thereby, the temperature of the article 10 to be heated gradually decreases.

  In step S404, if the detected temperature of the infrared sensor 12 (IR) is not equal to or higher than the upper limit value, the control means 6 determines that the temperature of the object to be heated 10 is not a dangerous temperature, and the current contact temperature sensor 11 (TH ) And the detection temperature of the infrared sensor 12 are stored in a storage means (not shown) (step S405), and the previous detection temperature of the contact-type temperature sensor 11 stored in the storage means and the current contact type. The difference between the temperature detected by the temperature sensor 11 is calculated, and the temperature change of the object to be heated 10 is calculated from the predetermined time obtained from the time measuring means 7 and this difference. Further, the difference between the detected temperature of the previous infrared sensor 12 stored in the storage means and the detected temperature of the current infrared sensor 12 is calculated, and the object to be heated 10 is calculated from the predetermined time obtained from the time measuring means 7 and the difference. Is calculated (step S406). Next, the control means 6 compares the temperature change (gradient of temperature rise) of the heated object 10 calculated based on the temperature detected by the contact temperature sensor 11 (TH) with a reference value set in advance. (Step S407). If the temperature change (temperature increase gradient) of the article to be heated 10 is larger than the reference value, the temperature increase gradient is abnormally large, and it is determined that there is a high possibility that the dangerous temperature will be easily reached in this state. 5 is controlled to reduce the heating power supplied to the heating coil 4 by a predetermined value (for example, 0.1 W) (step S408), and then the process returns to step S402.

In the comparison in step S407, if the temperature change (temperature rise gradient) of the object to be heated 10 is within the reference value, the control means 6 calculates the temperature of the object to be heated 10 calculated based on the detected temperature IR of the infrared sensor 12. The temperature change (temperature rise gradient) is compared with another preset reference value (step S409). If the temperature change (temperature increase gradient) of the article to be heated 10 is larger than the other reference value, the temperature increase gradient is abnormally large, and it is determined that there is a high possibility that the dangerous temperature will be easily reached if it remains as it is. After controlling the inverter circuit 5 and reducing the heating power supplied to the heating coil 4 by a predetermined value (for example, 0.1 W) (step S408), the process returns to step S402.
Thus, the temperature detected by the temperature detecting means 13 individually by the detection signal of the contact temperature sensor 11 (TH) and the detection signal of the infrared sensor 12 (IR) within a predetermined time measured by the time measuring means 7. The control means 6 determines that the temperature increase gradient is abnormally large and that it is likely to easily reach the dangerous temperature if it is greater than the reference value. Since the amount of power supplied to the circuit 5 is suppressed, it is possible to prevent the article to be heated 10 from being overheated.
In the above example, the control means is configured to suppress the amount of power supplied to the heating coil 4 of the inverter circuit 5 when the gradient of temperature rise is abnormally large. However, the present invention is not limited to this. The amount of power supplied to the heating coil 4 of the circuit 5 may be stopped. In this case, the function is realized only by rewriting the processing content of step S408 in FIG. 4 as described above.

  In the comparison in step S409, if the temperature change of the object to be heated 10 is within a predetermined value, the control means 6 controls the inverter circuit 5 to improve the heating efficiency of the object to be heated 10 to thereby increase the heating coil 4. The heating power supplied to is increased by a predetermined value (for example, 0.1 W) (step S410). Next, the control means 6 checks whether or not the heating power currently supplied to the heating coil 4 has reached or exceeded a preset set power (this set power has the best heating efficiency) (step S411). ). When the heating power becomes larger than the set power, the control unit 6 controls the inverter circuit 5 to limit the heating power to the set power (step S412), and then returns to step S402. If the heating power is smaller than the set power in the comparison in step S411, the process returns to step S402, and the control means 6 controls the inverter circuit 5 so as to continue the same processing as described above. Thereby, efficient cooking is possible.

  According to the present embodiment, as described above, the temperature detection means is detected from the detection signal of the contact temperature sensor 11 (TH) and the detection signal of the infrared sensor 12 (IR) within a predetermined time measured by the time measurement means 7. The temperature rise gradient obtained by converting each of the temperature rises individually is checked, and if at least one of the temperature rise gradients is larger than the reference value, the control means 6 has an abnormally large temperature rise gradient. Since it is determined that there is a high possibility that the temperature will be easily reached and the amount of power supplied to the inverter circuit 5 is suppressed or energization is stopped, it is possible to prevent the article to be heated 10 from being overheated.

  Further, at least one of the temperatures individually detected by the temperature detecting means 13 based on the detection signal of the contact temperature sensor 11 (TH) and the detection signal of the infrared sensor 12 (IR) is used to determine the gradient of the temperature rise of the article 10 to be heated. If it is larger than the reference value, the control means 6 judges that the temperature is at a dangerous temperature, and stops supplying the heating power to the heating coil of the inverter circuit 5, thereby preventing the article to be heated 10 from being overheated. Can do.

  Further, since the control means 6 controls the inverter circuit 5 so that the heating power of the heating coil 4 becomes the set power with the highest efficiency when the temperature of the object to be heated 10 and the gradient of the temperature rise are normal, the efficiency is high. Heat cooking is possible.

Embodiment 2. FIG.
In Embodiment 1, if the detection accuracy of any one of the contact-type temperature sensor 11 and the infrared sensor 12 decreases for some reason, the accuracy of determining the temperature abnormality of the article to be heated 10 by the control means 6 decreases. Therefore, in order to solve such a problem, it may be configured to detect that one of the detection accuracy has deteriorated and to issue an alarm. This embodiment will be described in the second embodiment.
1 and 3 are also used in the second embodiment.
FIG. 5 is a block diagram showing a configuration of a control system in Embodiment 2 of the induction heating cooker according to the present invention. The configuration of FIG. 5 is the same as the configuration of FIG. 2 except that the alarm notification means 14 is added.
Moreover, FIG. 6 is a flowchart which shows the heating cooking process of the control means 6 in Embodiment 2 of the induction heating cooking appliance which concerns on this invention. The flowchart in FIG. 6 is the same as FIG. 4 except that steps S601 to S602 are added.
In FIG. 5, the alarm notification unit 14 includes a display unit or a voice output unit, and can display the input alarm information as a message or an image, display it as a voice, or combine them.
Next, the operation will be described with reference to FIG. 1, FIG. 3, FIG. 5, and FIG.
In FIG. 6, steps S401 to S406 operate in the same manner as in FIG. In step S <b> 601, the control unit 6 determines the gradient of the increase value (ΔTH value) at a predetermined time measured by the timing unit of the temperature TH detected by the contact temperature sensor 11 and the temperature detected by the infrared sensor 12. If there is a difference exceeding the predetermined value by comparing the gradient of the rising value (ΔIR value) at the predetermined time, it is determined that one of the temperature detection accuracy has deteriorated, and an alarm notification means is provided to that effect. 14 (step S602).
With such a configuration, the user who has recognized the alarm can stop the cooking by operating the corresponding switch of the operation unit 8 and can take countermeasures by pursuing the cause of deterioration in accuracy and performing repairs. Thus, it is possible to prevent deterioration in temperature detection accuracy. Moreover, the same effect as that of the first embodiment can be obtained by taking the countermeasure.

Embodiment 3 FIG.
Further, when a plurality of contact-type temperature sensors 11 are provided, if the detection accuracy of a specific object deteriorates, this may be specified and an alarm may be output. In Embodiment 3, such a form will be described.
1, 3 and 5 are also used in the third embodiment. In FIG. 5, only two contact-type temperature sensors 11 are shown, but the number is not limited to two, and it is assumed that there are a plurality. Here, it is assumed that there are n (n is an integer of 2 or more) number of contact temperature sensors 11 and these are TH1 to THn.
Moreover, FIG. 7 is a flowchart which shows the heating cooking process of the control means 6 in Embodiment 3 of the induction heating cooking appliance which concerns on this invention. The flowchart of FIG. 7 replaces steps S401, S402, S404, S405, S406, S601, and S407 of FIG. 6 with steps S701, S702, S704, S705, S706, S711, and S707, and adds step S712. The configuration is the same as that of FIG. Note that only step S711 is greatly different. In steps S701, S702, S704, S705, S706, S711, and S707, THi is a signal detected by the plurality of contact-type temperature sensors 11, and the temperature detection means 13 respectively. Are converted to temperatures TH1 to THn. In step S701, it means that the control means 6 acquires the temperature converted by the temperature detection means 13 from the outputs of the plurality of contact temperature sensors 11 (THi) and the temperature converted from the detection signal of the infrared sensor 12 (IR). doing. In step S702, the control means 6 compares the temperature detected by the contact temperature sensor 11 (THi) with a preset upper limit value (TH limit value) for the contact temperature sensor. Since the object to be heated 10 is too hot and dangerous, the inverter circuit 5 is controlled to stop supplying the heating power to the heating coil 4 (step S403), and then the process returns to step S702. It means to repeat for the number of units. Further, in step S705, the detected temperatures of the plurality of contact temperature sensors 11 (TH1 to THn) are simply stored in the storage means individually. In step S706, the control means 6 for each of the plurality of contact-type temperature sensors 11 stores the previous detected temperature of the contact-type temperature sensor 11 stored in the storage means and the current contact-type temperature sensor 11. The temperature change of the object to be heated 10 is calculated on the basis of the difference between the detected temperatures and the predetermined time obtained from the time measuring means 7, and the previous detected temperature of the infrared sensor 12 stored in the storage means and the current infrared sensor 12. The temperature change of the object to be heated 10 is calculated on the basis of the difference between the detected temperatures and the predetermined time obtained from the time measuring means 7.

In step S711, the temperature detection unit 13 converts the signals detected by the plurality of contact temperature sensors 11 (TH1 to THn) into a temperature and outputs the temperature to the control unit 6. When the control means 6 acquires the detected temperatures of the plurality of contact-type temperature sensors 11 (TH1 to THn) from the temperature detection means 13, the previous values of these temperatures stored in the storage device and a predetermined value obtained from the time measurement means 7 are obtained. Based on the time, the temperature is converted into a plurality of temperature rise values, and the gradients of the plurality of temperature rise values obtained by the conversion are compared with each other. As a result of the comparison, if a difference exceeding a predetermined value occurs, the control means 6 identifies the contact-type temperature sensor 11 (THi) that caused the difference according to the majority rule (step S712), and identifies the identified contact-type It is determined that the temperature detection accuracy of the temperature sensor 11 (THi) has deteriorated, and a warning to that effect is issued to the alarm notification means 14 (step S502). Thereafter, the process returns to step S702.
Thereby, the user who recognizes that the accuracy of the specific contact-type temperature sensor 11 has deteriorated due to the alarm excludes the detected temperature of the specified contact-type temperature sensor 11 or the contact-type temperature sensor 11 with this low accuracy. It is possible to prevent deterioration of accuracy by taking measures such as exchanging for a non-defective product.
In step S707, the control means 6 changes the temperature of the article 10 to be heated (gradient of temperature rise) calculated based on the detected temperature of each of the plurality of contact temperature sensors 11 (TH1 to THn) individually. Is compared with a preset reference value. As a result of the comparison, if the temperature change (temperature increase gradient) of the article to be heated 10 is larger than the reference value, the control means 6 may have an abnormally large temperature increase gradient and easily reach the dangerous temperature. The heating power supplied to the heating coil 4 is reduced by a predetermined value (for example, 0.1 W) (step S408), and then the process returns to step S702.
In the above example, if a difference exceeding a predetermined value is identified as a result of comparison between the temperature gradients calculated from the outputs of the plurality of contact temperature sensors 11 in step S712, the identification is performed. An alarm indicating that the temperature detection accuracy of the contact-type temperature sensor 11 has deteriorated is issued to the alarm notification means 14, but as shown in FIG. 8, step S801 is added between step S712 and step S502 of FIG. Then, the output of the specified contact-type temperature sensor 11 may be ignored, and an alarm to that effect may be issued to the alarm notification means 14.

Note that the above description is the same for the infrared sensor, and when a plurality of infrared sensors 12 are provided, the detection accuracy of a specific object can be specified.
In this case, the control unit 6 obtains a plurality of temperatures detected by the plurality of infrared sensors 12 from the temperature detection unit 13, compares the obtained plurality of temperatures with the previous temperature, and then compares the plurality of infrared sensors 12 with each other. And a plurality of temperature rise gradients are compared with each other, and if a difference occurs exceeding a predetermined value, the infrared sensor 12 that has generated the difference according to the majority rule. Is determined, and it is determined that the temperature detection accuracy of the specified infrared sensor 12 has deteriorated, and an alarm to that effect is issued. As a result, the user who has recognized that is specified by the alarm can prevent the deterioration of accuracy by ignoring the information of the specified infrared sensor 12 or taking a measure such as replacing it with a non-defective product. .

Embodiment 4 FIG.
In addition, when boiling occurs, the temperature rise stops and becomes almost constant and stable, so this boiling may be added to the conditions.
In this case, the control means 6 detects the object to be heated 10 detected by the contact-type temperature sensor 11 based on the output from the temperature detection means 13 every time when the time obtained from the time measuring means 7 elapses a predetermined time. The first temperature rise is calculated based on the previous temperature and the current temperature, and the second temperature rise is calculated based on the previous temperature and the current temperature of the object 10 detected by the infrared sensor 12. The calculated first temperature rise and second temperature rise are stored in advance in the storage means. During induction heating cooking, the control means 6 calculates the first temperature rise and the second temperature rise under the same conditions as described above, and the first temperature rise and the second temperature rise are predetermined. When it falls within the range, it is determined that the article to be heated 10 has boiled. Thereafter, the control means 6 compares the first temperature rise and the second temperature rise, and when a difference exceeding a predetermined value is detected, either the contact temperature sensor 11 or the infrared sensor 12 is detected. It is determined that the temperature detection accuracy has deteriorated, and a warning to that effect is issued to the alarm notification means 14. Thereby, there exists an effect similar to the above.

  A vibration sensor may be added as a boiling condition. In this case, the control means 6 detects the object to be heated 10 when it detects a vibration of a predetermined value or more for a predetermined time or more and when the first temperature rise and the second temperature rise are within a predetermined range. Judge that it has boiled. This further improves accuracy.

  Moreover, you may add the electric energy supplied to a heating coil as conditions of boiling. In this case, the control means 6 determines the amount of power supplied to the heating coil 4 based on the output of the inverter current detection means for detecting the output current of the inverter circuit 5 and the output of the inverter voltage detection means for detecting the bus voltage of the inverter circuit. Calculated from the temperature rise value calculated from the detection signal of the contact-type temperature sensor 11 and the detection signal of the infrared sensor 12 at a predetermined time obtained from the time measuring means 7 when the electric energy is within a predetermined range. When the temperature rise value falls within a predetermined range, it is determined that the object to be heated 10 has boiled. Thereby, temperature detection accuracy further improves.

  DESCRIPTION OF SYMBOLS 1 Induction heating cooker main body, 2 Top plate, 3, 3a-3c Heating part mark, 4, 4a-4c Heating coil, 5 Inverter circuit, 6 Control means, 7 Time measuring means, 8 Operation part, 9 Grill, 10 Heated Object (pot), 11 Contact type temperature sensor (thermistor), 12 Infrared sensor, 13 Temperature detection means, 14 Alarm notification means, 100 Induction cooking device.

Claims (5)

A top plate on which the object to be heated is placed;
A heating coil disposed below the top plate for induction heating the object to be heated;
An inverter circuit for supplying AC power to the heating coil;
A contact-type temperature sensor that contacts the back surface of the top plate and detects the heat of the object to be heated;
An infrared sensor for detecting infrared rays of the object to be heated;
Temperature detection means for converting the output of the contact-type temperature sensor and the output of the infrared sensor into a temperature;
Control means for controlling the inverter circuit,
The control means controls the inverter circuit to perform induction heating by the heating coil, and based on the temperature converted by the temperature detection means, the first temperature of the object to be heated is based on the temperature converted by the temperature detection means. A temperature increase gradient is calculated, a second temperature increase gradient of the object to be heated is calculated based on the temperature converted by the temperature detection means from the output of the infrared sensor, and the first temperature increase gradient or When at least one of the gradients of the second temperature rise exceeds a predetermined value, the power supply amount of the inverter circuit to the heating coil is suppressed or stopped ,
If the slope of the first temperature rise and the slope of the second temperature rise do not exceed a predetermined value, increase the amount of power supplied from the inverter circuit to the heating coil,
Equipped with a time measuring means for measuring the elapsed time from the start of cooking,
The control means calculates the first temperature rise and the second temperature rise based on the output of the temperature detection means every time when the time obtained from the time measuring means elapses a predetermined time. When the temperature rise of 1 and the second temperature rise are within a predetermined range, it is determined that the object to be heated has boiled, and the first temperature rise and the second temperature rise are compared. An induction heating cooker characterized in that, when a difference exceeding a predetermined value is detected, it is determined that the accuracy of either one has deteriorated . With vibration sensor,
The control means detects when a vibration of a predetermined value or more is detected for a predetermined time or more, and when the temperature rise is within a predetermined range from the output of the first temperature detection means and the output of the second temperature detection means. The induction heating cooker according to claim 1 , wherein it is determined that the object to be heated has boiled. Inverter output current detection means for detecting the output current of the inverter circuit;
An inverter voltage detecting means for detecting a bus voltage of the inverter circuit,
The control means calculates the amount of electric power supplied to the heating coil based on the output of the inverter output current detection means and the output of the inverter voltage detection means, the electric energy is within a predetermined range, and the first If the output and the output temperature increase from the second temperature detecting means 1 of the temperature detecting means becomes within a predetermined range, claim 1, wherein the determining the object to be heated has been boiled Induction heating cooker. Provided with alarm notification means for issuing an alarm by voice or display;
The induction heating cooker according to any one of claims 1 to 3 , wherein, when the control unit specifies a sensor having a deteriorated temperature detection accuracy, the control unit outputs the fact to the alarm notification unit. Provided with alarm notification means for issuing an alarm by voice or display;
4. The control device according to claim 1 , wherein when the sensor having a deteriorated temperature detection accuracy is specified, the output of the specified sensor is ignored and the fact is output to the alarm notification device. The induction heating cooker of crab.

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