JP2010073466A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker which changes an output of an infrared sensor and a preheating completion determination value of an input power-integrated value in response to heating power in order to complete preheating for a short time even in low power. <P>SOLUTION: The induction heating cooker includes: a control part (8) for controlling an output of an inverter circuit based on an output of the infrared sensor; and an input power integration part 81 for integrating input power. In the induction heating cooker, the input power integration part 81 switches an integrated value for shifting to a standby mode based on an input current detected by an input current detection part 9. A preheating mode heats a cooker by a first heating output corresponding to the preheating mode, causes a reporting part to report the completion of preheating when an increase amount of an output value of the infrared sensor exceeds a first predetermined increase amount after heating is started by the first heating output or the integrated value exceeds a first predetermined value, and also shifts to the standby mode for heating by a second heating output lower than the first heating output. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an induction heating cooker that heats an object to be heated such as a cooking container.

  In recent years, induction heating cookers that induction-heat cooking containers such as pans and frying pans with a heating coil have been widely used in general households and commercial kitchens. The induction heating cooker is provided with a thermal element such as a thermistor on the lower surface of the top plate, detects the temperature of the bottom surface of the cooking container with the thermal element, and controls the heating coil so that the detected temperature matches the target temperature. Yes. For example, when preheating the cooking container before fried food cooking, control is performed so that the temperature detected by the thermal element reaches the target temperature during preheating.

  The temperature rise at the bottom of the cooking container is moderate when a large amount of oil or food is in the pan (when the load is large) as in fried food cooking, but when only a small amount of oil is put in the pan (load) Is small). On the other hand, the thermal element detects the temperature of the bottom surface of the cooking container placed on the top plate by detecting the heat conducted from the cooking container to the top plate. Followability is not good. Therefore, when the temperature of the bottom surface of the cooking container rises rapidly, an error between the actual temperature of the bottom surface of the cooking container and the temperature detected by the thermal element increases. As a result, even if the actual temperature of the bottom surface of the cooking container reaches the target temperature, this cannot be detected and heating is continued, and the temperature of the bottom surface of the cooking container far exceeds the target temperature and oil ignition occurs. In some cases, dangerous temperatures such as temperature could be reached.

Therefore, conventionally, this type of induction heating cooker detects the temperature gradient of the bottom surface of the cooking container, and when the temperature gradient is steeper than a predetermined temperature gradient, by stopping heating, The heating coil is controlled so that the temperature of the bottom surface does not reach the dangerous temperature (see, for example, Patent Document 1).
JP-A 64-33881

  However, in the conventional configuration, when the load is small, for example, when cooking fried food that starts cooking with a small amount of oil, the stop of heating may be delayed as described below.

  Since the thermosensitive element detects the temperature of the bottom surface of the cooking container by detecting the temperature of the bottom surface of the top plate, the gap between the bottom surface of the cooking container and the top plate at the position where the temperature is detected by the thermosensitive element is large. And greatly affects the relationship between the detected temperature and the actual bottom temperature of the cooking container. In particular, when the pan bottom is warped, a large gap is formed between the pan bottom and the top plate. In this case, since the temperature at the bottom of the pan is not easily transmitted to the top plate, the temperature gradient calculated based on the temperature detected by the thermal element is gentler than the actual temperature gradient at the bottom of the pan. For this reason, there was a case where the heating stop was delayed.

  Moreover, when the thickness of the bottom surface of the cooking container is thin, the bottom surface temperature of the cooking container rapidly increases. On the other hand, it takes time for heat to be transferred from the bottom surface of the cooking container to the bottom surface of the top plate. Therefore, even if the same inclination as the temperature gradient of the bottom surface of the actual cooking container can be detected, there is a case where a time delay occurs until the detection is made, and the stop of heating may be delayed.

Thus, since the conventional induction heating cooker controls the stop of heating based on the temperature gradient calculated based on the detected temperature of the thermosensitive element, the stop of heating may be delayed. If the stoppage of heating is delayed, there arises a problem that the temperature of the bottom surface of the cooking container far exceeds the target temperature, and thereafter it takes a long time to stabilize at the target temperature. On the other hand, when the load is small, in order for the conventional induction heating cooker to prevent the temperature of the bottom surface of the cooking container from exceeding the target temperature, heating must be started with low heating power.

  Moreover, when using a some heating part simultaneously, a predetermined heating part must be heated with low heating power by total electric power regulation. For example, when temperature is detected by a sensor such as a silicon photodiode, an output capable of detecting temperature cannot be reached in a short time.

  Therefore, the conventional induction heating cooker has a problem in that when the load is small, for example, when fried food cooking is started with a small amount of oil, the temperature of the object to be heated cannot reach the target temperature in a short time. there were. In addition, when using a plurality of heating units simultaneously, there is a problem that the target temperature cannot be appropriately reached in a short time even if the predetermined heating unit has to be heated with low heating power due to total power regulation. there were.

  For this reason, it was not possible to complete proper preheating when cooking fried foods using a frying pan.

  The present invention solves the above-described conventional problems, and the temperature of an object to be heated can be set to a target temperature in a short time even in low thermal power heating based on total power regulation when the load is small and a plurality of heating units are used simultaneously. An object of the present invention is to provide an induction heating cooker that reaches the point. Specifically, an object of the present invention is to provide an induction heating cooker that completes preheating in a short time when cooking a fried food using a frying pan.

  In order to achieve the above object, an induction heating cooker according to the present invention includes a top plate formed of a material that transmits infrared rays, and a cooking vessel placed on the top plate by being supplied with a high-frequency current. A heating coil for induction heating, an inverter circuit for supplying a high-frequency current to the heating coil, an operation unit for setting the operation mode of the inverter circuit, and infrared rays radiated from the bottom surface of the cooking container and transmitted through the top plate are detected. An infrared sensor, a control unit that controls the output of the inverter circuit based on the output of the infrared sensor, and a notification unit.

  In addition, when using a plurality of heating coils at the same time, the control unit regulates the output so as not to exceed the total power consumption.

  The operation unit has a preheating selection unit for selecting a preheating mode. In this case, when the preheating mode is selected, the cooking container is heated with the first heating output corresponding to the preheating mode, and the amount of increase in the output value of the infrared sensor after starting the heating with the first heating output is the first. If it exceeds 1 predetermined increase amount, an alerting | reporting part alert | reports that the preheating was completed, and transfers to the standby mode heated with the 2nd heating output lower than a 1st heating output.

  In addition, the control unit includes an input power integration unit that integrates the input power, and the integrated value of the input power after starting heating with the first heating output integrated by the input power integration unit exceeds the first predetermined value. And enter standby mode.

  In addition, when the first heating output is heated at an output lower than the predetermined output due to the output restriction by simultaneous use of the heating coil before shifting to the standby mode, the first predetermined value of the integrated value is set to the first heating output. Change the value accordingly. Even if the output restriction is canceled and the first heating output returns to the heating output before the output restriction, the first predetermined value of the integrated value is not switched to the value before the output restriction.

  When the output restriction is applied, the increase amount of the output value of the infrared sensor is switched to the second predetermined increase amount that is smaller than the first predetermined increase amount. When the output restriction is released, the increase amount of the output value of the infrared sensor is switched to the first predetermined increase amount.

  In addition, the transition to the standby mode is configured such that priority is given to the first predetermined increase amount or the first predetermined value that has been exceeded first.

  The induction heating cooker may further include a display unit. In this case, the display unit may perform a predetermined display during the output restriction before the transition to the standby mode.

  The infrared sensor may be provided in the radial direction of the winding of the heating coil. The infrared sensor may comprise a silicon photodiode.

  According to the cooking device of the present invention, by detecting the temperature of the bottom surface of the cooking container using an infrared sensor, the temperature of the bottom surface of the actual cooking container can be accurately detected with good thermal responsiveness, If heating is unavoidable as in the case of total power regulation, the target power of the infrared sensor is lowered or the integrated power is switched by thermal power in the case of low thermal heating that cannot reach the output of the infrared sensor. Thus, the temperature of the object to be heated can reach the target temperature in a short time. Specifically, by using an infrared sensor, the heating power in the preheating mode can be set large even during cooking of fried food using a frying pan, so that preheating can be completed in a short time, and the total In the case of low heating power heating that cannot reach the output level of the infrared sensor at the time of power regulation, usability can be improved by using the integrated power value together.

(Embodiment 1)
FIG. 1 shows a configuration diagram of an induction heating cooker according to the first embodiment of the present invention. The induction heating cooker according to the present embodiment includes a “preheating heating function” that performs preheating until the target temperature is reached before heating at a high heating power such as stir-fried food. Control during preheating and heating is performed by using an output signal corresponding to the temperature of the article 10 to be heated. This induction heating cooker is used by being incorporated in a cabinet such as a kitchen, for example.

  An induction heating cooker according to an embodiment of the present invention includes a top plate 1 provided on an upper surface of a device and a heating coil 2 (outside) that induction-heats an object to be heated 10 on the top plate 1 by generating a high-frequency magnetic field. A coil 2a and an inner coil 2b). The top plate 1 is made of an electrical insulator such as glass and transmits infrared rays. The heating coil 2 is provided below the top plate 1. The heating coil 2 is divided into two concentric circles to form an outer coil 2a and an inner coil 2b. A gap is provided between the outer coil 2a and the inner coil 2b. The object to be heated 10 generates heat due to the eddy current generated by the high frequency magnetic field of the heating coil 2.

  On the user side of the top plate 1, an operation unit 4 is provided for the user to instruct the start / stop of heating. A display unit 12 is provided between the operation unit 4 and the article to be heated 10. A light source 14 for irradiating the operation unit 4 and the display unit 12 is provided below the operation unit 4 and the display unit 12.

The infrared sensor 3 is provided below the gap between the outer coil 2a and the inner coil 2b. Since the high-frequency magnetic field of the heating coil 2 is strong at this position, the substantially maximum temperature of the bottom surface of the object to be heated 10 can be detected. Infrared radiation based on the bottom surface temperature of the object to be heated 10 radiated from the bottom surface of the object to be heated 10 is incident through the top plate 1, passes through a gap between the outer coil 2 a and the inner coil 2 b, and is an infrared sensor. 3 is received. The infrared sensor 3 detects received infrared rays and outputs an infrared detection signal 35 based on the detected amount of infrared rays.

  Below the heating coil 2, a rectifying / smoothing unit 6 that converts an AC voltage supplied from the commercial power supply 5 into a DC voltage, a DC voltage supplied from the rectifying / smoothing unit 6 to generate a high-frequency current, and the generated high-frequency current Is provided to the heating coil 2. An input current detection unit 9 for detecting an input current flowing from the commercial power supply 5 to the rectifying / smoothing unit 6 is provided between the commercial power supply 5 and the rectifying / smoothing unit 6.

  The rectifying / smoothing unit 6 includes a full-wave rectifier 61 composed of a bridge diode, and a low-pass filter composed of a choke coil 62 and a smoothing capacitor 63 connected between the output terminals of the full-wave rectifier 61. The inverter circuit 7 has a switching element 73 (IGBT in the present embodiment), a diode 72 connected in antiparallel with the switching element 73, and a resonant capacitor 71 connected in parallel with the heating coil 2. When the switching element 73 of the inverter circuit 7 is turned on / off, a high frequency current is generated. The inverter circuit 7 and the heating coil 2 constitute a high frequency inverter.

  The induction heating cooker of the present embodiment further includes a control unit 8 that controls the high-frequency current supplied from the inverter circuit 7 to the heating coil 2 by controlling on / off of the switching element 73 of the inverter circuit 7. Have. The control unit 8 controls on / off of the switching element 73 based on the signal transmitted from the operation unit 4 and the temperature detected by the infrared sensor 3.

  The control unit 8 includes an input power integration unit 81 that integrates input power. The input power integration unit 81 integrates the input power based on the input current detected by the input current detection unit 9. For example, the input power integration unit 81 calculates an integrated value of input power after starting preheating.

  The induction heating cooker of the present embodiment further has a notification unit 13. The notification unit 13 is, for example, a speaker that outputs an electronic sound. Specifically, when the preheating is completed, the notification unit 13 outputs an electronic sound notifying that the preheating has been completed.

  FIG. 2 shows a top view of the top plate 1. On the upper surface or the lower surface of the top plate 1, at least two heating portions 11 that indicate the placement place of the object to be heated 10 are displayed by printing. The heating coils 2 are respectively disposed below the heating unit 11. A display unit 12 is provided on the front side (user side) of the heating unit 11. The display unit 12 displays the magnitude of the output of the heating coil 2, the remaining time of the timer, characters for identifying the operation mode, and the like. The operation mode is a mode in which the operation of the inverter circuit 7 is set to be suitable for preheating, heating, deep-fried food, boiling water, and rice cooking.

  The operation unit 4 is provided on the front side (user side) of the display unit 12. The operation unit 4 includes a plurality of capacitance type switches 4a to 4f. The switches 4 a to 4 e are switches for inputting instructions related to cooking, and are provided corresponding to the number of heating units 11.

  Specific functions are assigned to the switches 4a to 4f, respectively. For example, the switch 4a is a turn-on / off switch to which a function for controlling the start and end of cooking is assigned.

  The switch 4b is a menu switch to which a function for switching to an operation mode suitable for a cooking menu of “heating”, “preheating heating”, “fried food”, “water heater”, and “rice cooking” is assigned. By pressing the menu switch 4b, characters and illustrations blink in the order of “heating”, “preheating heating”, “fried food”, “water heater”, and “rice cooking”, and the selection of the operation mode is switched. When the operation mode of “heating”, “preheating heating”, “fried food”, “water heater”, “rice cooking” is selected, the operation mode selected is determined and determined when the off / on switch 4a is operated. The display corresponding to the selected operation mode is turned on, and the display corresponding to the operation mode that has not been determined is turned off.

  The switch 4c is a thermal power setting switch to which a function for increasing the thermal power is assigned. The switch 4d is a thermal power setting switch to which a function for reducing the thermal power is assigned. When the “heating” mode is set, the heating power can be set by the heating power setting switches 4c and 4d.

  The switches 4e and 4f are timer switches to which a function for setting the heating time is assigned.

  When detecting that the switches 4a to 4f are pressed, the control unit 8 controls the inverter circuit 7 based on the pressed switches to control the high-frequency current supplied to the heating coil 2.

  An example of display on the display unit 12 is shown in FIGS. Specifically, FIGS. 3A to 3C show examples when the “preheating heating” mode is selected and determined. When the menu switch 4b is operated and the “preheating heating” mode is selected, the characters “heating” and “preheating” blink (FIG. 3A). In this state, when the off / on switch 4a is operated, the “preheating heating” mode is determined and the preheating is started. At this time, the characters “heating” are lit and the characters “preheating” are blinking (FIG. 3B). During the preheating, the control unit 8 invalidates the heating power change based on the operation even if the heating power setting switches 4c and 4d are operated.

  When preheating is completed, the characters “preheating” disappear, only the characters “heating” remain lit, and the thermal power bar 111 is displayed (FIG. 3C). The display of the thermal power bar 111 at this time corresponds to the thermal power value when the preheating is completed. FIG. 3C shows that the thermal power after completion of preheating is “5”. Displaying the thermal power bar 111 indicates to the user that the operation of the thermal power setting switches 4c and 4d is effective. After the preheating is completed, the control unit 8 validates the thermal power change based on the operation of the thermal power setting switches 4c and 4d. In addition, the structure which displays a thermal power bar after a user operates a thermal power setting switch may not be displayed after completion of preheating.

  FIG. 4 shows a circuit diagram of the infrared sensor 3. The infrared sensor 3 includes a photodiode 31, an operational amplifier 32, and resistors 33 and 34. One end of each of the resistors 33 and 34 is connected to the photodiode 31, and the other end is connected to the output terminal and the inverting output terminal of the operational amplifier 32. The photodiode 31 is a light receiving element formed of silicon or the like through which a current flows when irradiated with infrared rays having a wavelength of about 3 microns or less that passes through the top plate 1. The current generated by the photodiode 31 is amplified by the operational amplifier 15 and is output to the control unit 8 as an infrared detection signal 35 (corresponding to the voltage value V) indicating the temperature of the object 10 to be heated. The infrared sensor 3 receives infrared rays emitted from the object to be heated 10, and therefore has better thermal response than a thermistor that detects the temperature via the top plate 1.

FIG. 5 shows the output characteristics of the infrared sensor 3. In FIG. 5, the horizontal axis represents the bottom surface temperature of the object to be heated 10 such as a cooking container, and the vertical axis represents the voltage value of the infrared detection signal 35 output from the infrared sensor 3. The infrared detection signal 35 has output characteristics 35a to 35c based on the influence of ambient light. The output characteristic 35a indicates the output of the infrared detection signal 35 when no disturbance light is present, that is, when only infrared rays emitted from the article to be heated 10 are received. The output characteristic 35 b indicates the output of the infrared detection signal 35 when weak disturbance light is incident on the infrared sensor 3. The output characteristic 35c indicates the output of the infrared detection signal 35 in the case where strong disturbance light such as sunlight enters.

  In the present embodiment, since the purpose is to perform preheating when a high thermal power such as a stir-fried food is required, the target temperature during preheating is high (for example, 280 ° C.). Therefore, it is only necessary to obtain an output at a high temperature. Therefore, the infrared sensor 3 of the present embodiment outputs the infrared detection signal 35 when the bottom surface temperature of the article to be heated 10 is about 250 ° C. or higher, as shown by the output characteristic 35a, and when it is less than about 250 ° C. The infrared detection signal 35 is not output. In this case, “not outputting the infrared detection signal 35” means not only outputting the infrared detection signal 35 but also not substantially outputting it, that is, the control unit 8 is based on a change in the magnitude of the infrared detection signal 35. Output of a weak signal that cannot substantially read the temperature change of the bottom surface of the object to be heated 10. The output value of the infrared detection signal 35 increases exponentially when the temperature of the article to be heated 10 is about 250 ° C. or higher.

  When weak disturbance light is incident on the infrared sensor 3, a signal having a small value due to the disturbance light is output even when the temperature is less than about 250 ° C., as indicated by the output characteristic 35b. When strong disturbance light such as sunlight is contained, a large value signal is output even when the temperature is less than about 250 ° C., as in the output characteristic 35c.

  As described above, the infrared detection signal 35 output from the infrared sensor 3 is affected by disturbance light. Therefore, in the present embodiment, the completion of preheating, that is, whether or not the object to be heated 10 has reached the target temperature is determined by whether the output increase amount ΔV of the voltage value V of the infrared detection signal 35 from when the preheating is started is predetermined. Judgment is made based on whether or not the increase of

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

  First, in (a), (b), and (c) of FIG. 6, the temperature (° C.) of the cooking container when the “preheating heating” mode is performed, the output increase amount (ΔV) of the infrared sensor 3, A heating power amount (W) is shown. The horizontal axis of Fig.6 (a) (b) (c) has shown time. Further, the first output increase amount ΔV1 in FIG. 6B indicates the output increase amount ΔV of the infrared sensor 3 from the start of the preheating.

  When the menu switch 4b is operated to select the “preheating heating” mode, the control unit 8 starts preheating with a predetermined heating power amount (first heating output, for example, 3 kW). Preheating is continued with the first heating output until the output increase amount ΔV of the infrared sensor 3 reaches the first predetermined increase amount ΔV1 (preheating mode). When the output increase amount ΔV of the infrared sensor 3 reaches the first predetermined increase amount ΔV1, it is determined that the article to be heated 10 has reached the target temperature for preheating, and an electronic sound for notifying completion of preheating is output from the notification unit 13. .

  After the preheating is completed, the standby mode is entered. The standby mode is a mode for maintaining the temperature of the article to be heated 10 at the time of completion of preheating until completion of preheating and setting of the thermal power by the user. In the standby mode, heating is started with a heating power amount (second heating output, for example, 1 kW) smaller than that in the preheating mode.

At the same time, when the output increase amount ΔV of the infrared sensor is less than the first predetermined increase amount ΔV1, the control unit 8 determines whether or not the integrated value of the input power after starting preheating exceeds a predetermined value. . When the integrated value of the input power exceeds a predetermined value, a preheating completion notification is performed. When the object to be heated 10 is a cooking container made of a glossy metal such as aluminum, the infrared radiation emissivity is very low. Does not rise immediately. Therefore, in the present embodiment, even when the object to be heated 10 is a metal pan, the preheating is completed based on the integrated value of the input power after starting the preheating so that the preheating can be completed accurately. Do.

  Further, as shown in FIG. 7, the integrated value of the input power described above is the integrated value when the first heating output is heated at an output lower than a predetermined output due to the total power output restriction by simultaneous use of the heating coil. The first predetermined value is switched according to the first heating output. In addition, the magnitude relationship of the value by output control shall be as showing in FIG.

  When the output restriction is released and the first heating output returns to the heating output before the output restriction, the first predetermined value of the integrated value is not switched to the value before the output restriction. This is because the integrated value does not detect the preheat notification target temperature, and the integrated value before output regulation is smaller than the integrated value after output regulation. This is to prevent (at a temperature lower than the target temperature). In addition, when the integrated value is not switched to the value before output regulation, even if the integrated value after switching is larger, it is used together with the infrared sensor, so overheating even if the heating output returns (maximum heating power) Never become.

  Further, when the output restriction is applied, if the increase amount of the output value of the infrared sensor is a heating output that cannot reach the first predetermined increase amount ΔV1 in a short time, the second predetermined amount smaller than the first predetermined increase amount ΔV1. By switching to the increase amount ΔV2, detection is performed in the vicinity of a predetermined preheating target temperature, and a preheating notification can be reached.

  When the output restriction is canceled, the increase amount of the output value of the infrared sensor may be switched from the second predetermined increase amount ΔV2 to the first predetermined increase amount ΔV1.

  In addition, the transition to the standby mode is configured such that priority is given to the first predetermined increase amount or the first predetermined value that has been exceeded first.

  As described above, in the present embodiment, since the temperature of the object to be heated 10 is detected by the infrared sensor 3 having good thermal responsiveness, the actual temperature of the object to be heated 10 can be accurately detected. it can. For example, even when the bottom surface of the cooking container is warped or the bottom surface of the cooking container is thin, the actual temperature of the object to be heated 10 can be accurately detected without causing a time delay. Can do. Therefore, even if preheating is started at a high heating power (first heating output, for example, 3 kW), the temperature of the object to be heated 10 does not greatly exceed the target temperature, and the temperature of the object to be heated 10 reaches the target temperature. This can be immediately detected by the infrared sensor 3. Therefore, preheating can be started with high thermal power. Therefore, the target temperature is reached in a short time. Therefore, preheating before heating can be completed in a short time even when cooking fried food that starts cooking with a small amount of oil and high heating power.

  In this configuration, when the first heating output is lowered due to the total power output restriction due to simultaneous use of the heating unit, the output of the infrared sensor 3 is difficult to output, and the preheating target temperature cannot be reached in a short time However, the integrated value (first predetermined value) of the input power for performing the preheating notification can be switched in accordance with the level of output regulation, and the preheating notification can be reliably performed in a short time in the vicinity of the target temperature.

Further, when the output restriction is applied, the second predetermined increase amount smaller than the first predetermined increase amount when the increase amount of the output value of the infrared sensor is a heating output that cannot reach the first predetermined increase amount in a short time. By switching to, detection is performed in the vicinity of the predetermined preheating target temperature, and the preheating notification temperature can be reached.

  Further, since the silicon photodiode 31 is used as the light receiving element of the infrared sensor 3, the infrared sensor 3 can be made inexpensive.

  Moreover, in order to complete preheating based not only on the output increase amount of the infrared sensor 3 but also on the integrated value of the input power, overheating is prevented even in a cooking container having a very low emissivity, and appropriate preheating control is performed. It can be carried out.

  The notification unit 13 may be a speaker that outputs a voice guide, an LED, a liquid crystal, or the like.

  In the present embodiment, the infrared sensor 3 outputs the infrared detection signal 35 when the temperature is about 250 ° C. or higher, but this value is not limited to about 250 ° C. For example, the temperature may be lower or higher than 250 ° C. However, in consideration of making the infrared sensor 3 inexpensive and the variation of the circuit of the control unit 8, the output of the infrared detection signal 35 is preferably started at a temperature in the range of 240 ° C. to 260 ° C.

  Since the induction heating cooker of the present invention can complete preheating of the cooking container in a short time, it is useful for an induction heating cooker used in ordinary homes, restaurants, etc. where fried foods are cooked.

The block diagram which shows the structure of the induction heating cooking appliance of embodiment of this invention Top view of the top plate of FIG. (A) The figure which shows the example of a display of the display part which is selecting the "preheating heating" mode (b) The figure which shows the example of a display of the display part during preheating (c) The figure which shows the example of a display of the display part after completion of preheating Circuit diagram of the infrared sensor of FIG. Characteristics diagram of infrared sensor of FIG. (A) The figure which shows the temperature of a cooking vessel (b) The figure which shows the output increase amount of an infrared sensor (c) The figure which shows heating electric energy The figure which shows the change of various values at the time of total electric power regulation and the figure which shows the magnitude relation

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top plate 2 Heating coil 2a Outer coil 2b Inner coil 3 Infrared sensor 4 Operation part 4a-4f Switch 5 Commercial power supply 6 Rectification smoothing part 7 Inverter circuit 8 Control part 9 Input current detection part 10 To-be-heated object 11 Heating part 12 Display part 13 Notification Unit 14 Light Source 31 Photodiode 32 Operational Amplifier 61 Full Wave Rectifier 62 Choke Coil 63 Smoothing Capacitor 71 Resonance Capacitor 72 Diode 73 Switching Element 81 Input Power Integration Unit

Claims (7)

There are at least two or more heating coils, a top plate formed of a material that transmits infrared rays, a heating coil that induction-heats a cooking vessel placed on the top plate by being supplied with a high-frequency current. And an inverter circuit for supplying a high-frequency current to the heating coil, an operation unit for setting an operation mode of the inverter circuit, and an infrared ray that is radiated from the bottom surface of the cooking vessel and detects infrared rays that have passed through the top plate A control unit that controls an output of the inverter circuit based on an output of the sensor and the infrared sensor, and a notification unit, the control unit including an input power integration unit that integrates input power, and the heating When using a plurality of coils simultaneously, the output is regulated so as not to exceed the total power consumption, and the operation unit selects the preheating mode. If the preheating mode is selected, the cooking container is heated with a first heating output corresponding to the preheating mode, and the infrared rays after heating is started with the first heating output. The amount of increase in the output value of the sensor exceeds the first predetermined increase amount, or the integrated value of the input power after starting heating with the first heating output integrated by the input power integration unit becomes the first predetermined value. If exceeded, the notification unit notifies the completion of preheating, and shifts to a standby mode in which heating is performed at a second heating output lower than the first heating output, and the transition to the standby mode is performed by the first predetermined increase. It is configured to give priority to the amount or the first predetermined value that has been exceeded, and before the transition to the standby mode, the first heating output is more than the predetermined output by the output regulation by simultaneous use of the heating coils. When heating at low output The first predetermined value of the integrated value, the induction heating cooker and switches the value in response to the first heating output. 2. The first predetermined value of the integrated value is not switched to a value before the output restriction even if the output restriction is released and the first heating output returns to the heating output before the output restriction. Induction heating cooker. The induction heating cooker according to claim 1 or 2, wherein when the output restriction is applied, the amount of increase in the output value of the infrared sensor is switched to a second predetermined increase amount that is smaller than the first predetermined increase amount. The induction heating cooker according to any one of claims 1 to 3, wherein when the output restriction is canceled, an increase amount of the output value of the infrared sensor is switched to the first predetermined increase amount. The induction heating cooker according to any one of claims 1 to 4, wherein the induction heating cooker further includes a display unit, and the display unit performs a predetermined display during the output regulation before shifting to the standby mode. The induction heating cooker according to any one of claims 1 to 5, wherein the induction heating cooker further includes an audio output unit, and the audio output unit notifies the state during the output regulation before the transition to the standby mode by audio. vessel. The induction heating cooker according to claim 1, wherein the infrared sensor includes a silicon photodiode.