JP5747178B2 - Induction heating cooker and its program - Google Patents

Description

  The present invention relates to an induction heating cooker for induction heating a cooking vessel and a program thereof.

  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.

  FIG. 8 shows an induction heating cooker according to the prior art described in Patent Document 1. As shown in FIG. 8, it has an induction heating coil 12 and an infrared sensor 13 provided inside the main body, and a cooking vessel mounting surface 14 partially or entirely composed of a material that transmits infrared rays, The sensor 13 detects the temperature of the cooking vessel 15 by receiving infrared rays emitted from the cooking vessel 15 placed on the cooking vessel placement surface 14, and takes the output of the infrared sensor 13 into the feedback loop of the heating control system, Control heating.

  In addition, when the placement position of the cooking container 15 is inappropriate, when the rate of increase in the detected temperature of the infrared sensor 13 is small by looking at the ratio of elapsed time and temperature information, the placement position is inappropriate. A signal is sent to the alarm unit to alert the user.

Japanese Patent Laid-Open No. 3-184295

  In the configuration according to the prior art, when the rate of increase in the detected temperature of the infrared sensor 13 is small in view of the ratio between the elapsed time and the temperature information, the mounting position is inappropriate. However, the influence of the heat capacity of the cooking container 15 and the cooking object in the cooking container 15 is large on the increase value of the detected temperature of the infrared sensor 13 with respect to the elapsed time. Even when the mass of the cooking container is large or when the amount of oil put into the cooking container 15 is large, the temperature rise of the cooking container with respect to the elapsed time is small, and there is a problem of erroneously detecting that the placement position is inappropriate. It was.

  The object of the present invention is to solve the problems of the prior art, and whether the placement position is inappropriate without erroneous detection even when the mass of the cooking container is large or the amount of oil put into the cooking container is large. It is to provide an induction heating cooker that can be used safely and a program thereof.

An induction heating cooker according to the present invention includes a top plate formed of a material that transmits infrared rays, and a heating coil that induction-heats a cooking vessel placed on the top plate by being supplied with a high-frequency current. , An inverter circuit for supplying the high-frequency current to the heating coil, and infrared rays radiated from the bottom surface of the cooking vessel and transmitted through the top plate, and a detection signal corresponding to the bottom surface temperature is amplified and output by an amplifier an infrared sensor for a bottom temperature calculation section for calculating the bottom temperature from an output of the infrared sensor, based on an output of the bottom temperature calculation unit, e Bei a heating control section for controlling the heating output of the inverter circuit the infrared sensor is to increase the bottom temperature of the cooking vessel, the rate of increase in the output of the infrared sensor at a substantially zero is less than a predetermined temperature The amplification factor of the amplifier is set so as to increase in a power function when the temperature is equal to or higher than the predetermined temperature, and the heating control unit has a calculated temperature of the bottom surface temperature calculating unit at the start of heating that is equal to or higher than the predetermined temperature, and There line to stop the heating operation of suppressing or the inverter circuit of the heating output when less than the predetermined threshold temperature increase of the calculated temperature from the start of heating until a predetermined time elapses, the predetermined threshold value The calculation from the start of heating when the mass of the cooking container is large or when the amount of oil put into the cooking container is large and when the cooking container is properly placed until the predetermined time elapses The temperature is set to be smaller than the temperature rise .

In addition, a program for an induction heating cooker according to the present invention includes a top plate formed of a material that transmits infrared rays, and a cooking container placed on the top plate by being supplied with a high-frequency current. A heating coil for induction heating, an inverter circuit for supplying the high-frequency current to the heating coil, and an infrared ray radiated from the bottom surface of the cooking vessel and transmitted through the top plate to detect a detection signal corresponding to the bottom surface temperature An infrared sensor that amplifies and outputs by an amplifier, a bottom surface temperature calculation unit that calculates the bottom surface temperature from the output of the infrared sensor, and heating that controls the heating output of the inverter circuit based on the output of the bottom surface temperature calculation unit for example Bei and a control unit,
The infrared sensor is configured such that the increase rate of the output of the infrared sensor is substantially zero when the temperature is lower than a predetermined temperature and increases as a power function when the temperature is equal to or higher than the predetermined temperature with respect to an increase in the bottom temperature of the cooking container. , The amplification factor of the amplifier is set,
The heating control unit is configured such that at the start of heating, the calculated temperature of the bottom surface temperature calculating unit is equal to or higher than the predetermined temperature, and the temperature increase of the calculated temperature from the start of heating until a predetermined time elapses is less than a predetermined threshold value. the have a row to stop the heating operation of suppressing or the inverter circuit of the heating power, the predetermined threshold amount of oil placed in the case or the cooking vessel mass of the cooking container is large the case when a large amount in And a step that is set to be smaller than a temperature increase of the calculated temperature from the start of heating when the cooking container is properly placed until a predetermined time elapses .

  As a result, when heating is started with the cooking container position being inappropriate and not being placed on the infrared sensor, sunlight including infrared rays entering the room or windows is transmitted through the top plate. The infrared sensor outputs a detection signal as if the bottom surface temperature exceeded the predetermined temperature, and the calculated temperature of the bottom surface temperature calculation unit exceeds the predetermined temperature or the mass of the cooking container Only when the calculated temperature of the bottom surface temperature calculation unit at the start of heating is equal to or higher than the predetermined temperature even when the amount of food and oil put into the cooking container is large and the temperature rise with respect to the elapsed heating time is small In order to determine whether the temperature rise of the calculated temperature from the start of heating until the elapse of a predetermined time is less than a predetermined threshold value, it is determined whether the placement position of the cooking container is inappropriate. Well placed position can determine improper, cooking vessel improve safety reduces the chances that is heated improperly placed, it is possible to improve the usability.

According to the induction heating cooker of the present invention, the calculation result of the bottom surface temperature calculation unit at the start of heating is when the mass of the cooking container is large or when the amount of oil put into the cooking container is large, and the cooking container is The calculated temperature from the start of heating until the predetermined time elapses only when the temperature is equal to or higher than the predetermined temperature set to be smaller than the temperature rise of the calculated temperature from the start of heating when it is properly placed until the predetermined time elapses. In order to determine whether the temperature rise is less than a predetermined threshold and determine whether the cooking container is placed in an inappropriate position, the amount of food and oil that can be put into the cooking container when the cooking container is large in mass It is possible to accurately determine whether the placement position is inappropriate even when there is a large amount of food, and it is possible to reduce the chance that the cooking container is placed inappropriately and be heated, thereby improving safety and improving usability.

It is a block diagram which shows the structure of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a circuit diagram of the infrared sensor of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is an output characteristic graph of the infrared sensor of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a temperature calculation graph of the temperature calculation part of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a figure which shows the state in which the mounting position of the cooking container of the induction heating cooking appliance which concerns on Embodiment 1 of this invention is inappropriate. It is a characteristic graph of an infrared sensor when the mounting position of the cooking container of the induction heating cooking appliance which concerns on Embodiment 1 of this invention is inadequate, and detecting infrared rays, such as illumination. The flowchart which shows operation | movement of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a block diagram of the conventional induction heating cooking appliance.

An induction heating cooker according to a first aspect of the present invention is a heating that induction-heats a cooking vessel placed on the top plate by being supplied with a top plate formed of a material that transmits infrared rays and a high-frequency current. A coil, an inverter circuit that supplies the high-frequency current to the heating coil, and infrared rays that are radiated from the bottom surface of the cooking vessel and transmitted through the top plate, and a detection signal corresponding to the bottom surface temperature is amplified by an amplifier. An infrared sensor that outputs the temperature, a bottom surface temperature calculation unit that calculates the bottom surface temperature from the output of the infrared sensor, and a heating control unit that controls the heating output of the inverter circuit based on the output of the bottom surface temperature calculation unit. An induction heating cooker provided, wherein the infrared sensor increases an output rate of the infrared sensor with respect to an increase in a bottom surface temperature of the cooking container. The amplification factor of the amplifier is set so that it is substantially zero below a predetermined temperature and increases as a power function when the temperature is equal to or higher than the predetermined temperature, and the heating control unit Suppressing the heating output or stopping the heating operation of the inverter circuit when the calculated temperature is equal to or higher than the predetermined temperature and the temperature rise of the calculated temperature from the start of heating until a predetermined time elapses is less than a predetermined threshold value gastric row, said predetermined threshold is a case where the amount of oil to be taken into or if the cooking vessel mass of the cooking container is large multimers, and heating when the cooking vessel is properly placed It is set to be smaller than the temperature rise of the calculated temperature from the start until the predetermined time elapses . Thus, cooking is performed by determining whether the temperature rise of the calculated temperature from the start of heating until a predetermined time elapses is less than a predetermined threshold only when the calculated temperature of the bottom surface temperature calculation unit at the start of heating is equal to or higher than the predetermined temperature. In order to determine whether the placement position of the container is inappropriate, the cooking container can be used accurately even when the mass of the cooking container is large, or when the amount of food and oil put into the cooking container is large and the temperature rise with respect to the elapsed heating time is small. It is possible to determine whether or not the mounting position of the cooking container is improper, and it is possible to reduce the chance that the cooking container is improperly placed and heated, thereby improving safety and improving usability.

  The induction heating cooker according to the second invention is, in particular, the induction heating cooker according to the first invention, wherein the heating control unit is configured such that the calculated temperature of the bottom surface temperature calculation unit is equal to or higher than a predetermined temperature at the start of heating, and is heated. If the heating output is suppressed or the heating operation of the inverter circuit is stopped when the temperature rise of the calculated temperature from the start until the predetermined time elapses is less than the predetermined threshold value, a message such as a sound or a display device is sent to the user. This is notified by the notification unit. This can alert the user that the placement position is inappropriate.

A program for an induction heating cooker according to a third aspect of 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 the high-frequency current to the heating coil, and an infrared ray radiated from the bottom surface of the cooking vessel and transmitted through the top plate to detect a detection signal corresponding to the bottom surface temperature An infrared sensor that amplifies and outputs by an amplifier, a bottom surface temperature calculation unit that calculates the bottom surface temperature from the output of the infrared sensor, and heating that controls the heating output of the inverter circuit based on the output of the bottom surface temperature calculation unit e Bei and a control unit, the infrared sensor with respect to an increase in the temperature of the bottom surface of the cooking vessel, the rate of increase in the output of the infrared sensor a predetermined The amplification rate of the amplifier is set so that the increase rate of the magnitude of the detection signal is substantially zero below the temperature and increases as a power function when the temperature is equal to or higher than the predetermined temperature, and the heating control unit When the calculated temperature of the bottom surface temperature calculation unit is equal to or higher than the predetermined temperature at the start, the heating output is suppressed when the temperature rise of the calculated temperature from the start of heating to a predetermined time is less than a predetermined threshold value or There line to stop the heating operation of the inverter circuit, wherein the predetermined threshold is a case where the amount of oil to be taken into or if the cooking vessel mass of the cooking container is large multimers, and the cooking vessel is properly also executed by a computer, characterized in that it comprises the steps set as the start of heating when placed smaller than the temperature rise of the calculated temperature until a predetermined time elapses It is. Thus, cooking is performed by determining whether the temperature rise of the calculated temperature from the start of heating until a predetermined time elapses is less than a predetermined threshold only when the calculated temperature of the bottom surface temperature calculation unit at the start of heating is equal to or higher than the predetermined temperature. Precise cooking even when the mass of the cooking container is large, or when the amount of food and oil that can be put in the cooking container is large and the temperature rise with respect to the elapsed heating time is small by determining whether the container placement position is inappropriate It is possible to provide an induction heating cooker capable of causing a computer to execute a function of determining whether the placement position of the container is inappropriate. Moreover, since it is a program, at least one part of the induction heating cooking appliance of this invention can be easily implement | achieved by cooperating hard resources, such as an electrical / information apparatus, a computer, and a server. In addition, the program can be distributed / updated and installed easily by recording on a recording medium or distributing the program using a communication line.

  A program for an induction heating cooker according to a fourth aspect of the invention is particularly the program of the third aspect of the invention, wherein the heating control unit is configured such that when the calculated temperature of the bottom surface temperature calculating unit is equal to or higher than the predetermined temperature at the start of heating. When the heating output is suppressed or the heating operation of the inverter circuit is stopped when the temperature rise of the calculated temperature from the start of heating to the elapse of a predetermined time is less than a predetermined threshold value, a message to that effect is given to the user. It further includes a step of notifying by the notifying unit. This can further alert the user that the placement position is inappropriate.

  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 is a block diagram showing the configuration of the induction heating cooker according to Embodiment 1 of the present invention.

  In FIG. 1, a top plate 1 provided on the upper surface of the apparatus and a heating coil 3 for induction heating the cooking vessel 2 on the top plate 1 by generating a high frequency magnetic field are provided.

  The top plate 1 is made of a plate-like electrical insulator such as crystallized ceramic or heat-resistant glass, and transmits infrared rays. The heating coil 3 is provided below the top plate 1. The heating coil 3 is composed of an outer coil 3a and an inner coil 3b that are divided into two concentric circles and are electrically connected to each other (not shown).

  The bottom surface of the cooking container 2 generates heat due to the eddy current generated by the high frequency magnetic field of the heating coil 3. A gap 3c is provided between the outer coil 3a and the inner coil 3b in order to uniformize the temperature distribution on the bottom surface of the cooking container 2 when heat is generated.

  An operation unit 4 including a plurality of switches is provided on the user side of the top plate 1. For example, the operation unit 4 includes a heating start / stop switch for the user to instruct the start / stop of heating. For example, the switch can be configured with a touch key.

  The infrared sensor 5 is arranged to measure infrared rays emitted from the bottom surface of the cooking vessel 2 heated by the heating coil 3. The infrared sensor 5 may be arranged so as to measure the temperature of the bottom surface portion of the cooking container 2 located above the center of the heating coil 3, but the bottom surface portion of the cooking container 2 eccentric from the center of the heating coil 3. It is preferably provided to measure the temperature. This is because the bottom surface portion of the cooking container 2 above the winding portion between the outer periphery and the inner periphery of the heating coil 3 generally has a higher temperature than the upper portion at the center of the heating coil 3. In the present embodiment, it is provided below the gap 3c between the outer coil 3a and the inner coil 3b. The upper part of the gap 3c between the outer coil 3a and the inner coil 3b has a higher high-frequency magnetic field of the heating coil 3 than the upper part of the center of the heating coil 3, so that the substantially maximum temperature of the bottom surface of the cooking vessel 2 can be detected. it can.

  Infrared rays radiated from the bottom surface of the cooking vessel 2 corresponding to the bottom temperature of the cooking vessel 2 enter through the top plate 1 and pass through the gap 3c between the outer coil 3a and the inner coil 3b. And received by the infrared sensor 5. The infrared sensor 5 detects the received infrared ray and outputs an infrared detection signal 6 corresponding to the detected amount of infrared ray.

  Below the heating coil 3, a rectifying / smoothing unit 8 that converts an AC voltage supplied from the commercial power supply 7 into a smoothed DC voltage, and a DC voltage supplied from the rectifying / smoothing unit 8 generates a high-frequency current. And an inverter circuit 9 for outputting the high frequency current to the heating coil 3.

  The rectifying / smoothing unit 8 includes a full-wave rectifier 20 composed of a bridge diode, and a low-pass filter composed of a choke coil 21 and a smoothing capacitor 22 connected between output terminals of the full-wave rectifier 20.

  The inverter circuit 9 includes a switching element 23 (IGBT in the present embodiment), a diode 24 connected in antiparallel with the switching element 23, and a resonant capacitor 25 connected in parallel with the heating coil 3.

  When the switching element 23 of the inverter circuit 9 is turned on / off, a high frequency current is generated in the inverter circuit 9 and the heating coil 3. The inverter circuit 9 and the heating coil 3 constitute a high frequency inverter.

  The heating control unit 10 controls a high-frequency current supplied from the inverter circuit 9 to the heating coil 3 by outputting a drive signal for controlling on / off of the switching element 23.

  The heating control unit 10 controls on / off of the switching element 23 based on the signal transmitted from the operation unit 4 and the temperature detected by the infrared sensor 5 and calculated by the temperature calculation unit 11.

  The notification unit 26 notifies the user by sound or a display device based on the signal from the heating control unit 10.

  FIG. 2 shows a circuit diagram of infrared sensor 5 of the induction heating cooker according to Embodiment 1 of the present invention. In FIG. 2, the infrared sensor 5 includes a photodiode 51, an operational amplifier 52, and resistors 53 and 54. One ends of the resistors 53 and 54 are connected to the cathode of the photodiode 51, the other end of the resistor 54 is connected to the output terminal of the operational amplifier 52, and the other end of the resistor 53 is connected to the inverting input terminal. Both the anode of the photodiode 51 and the non-inverting input terminal of the operational amplifier 52 are grounded (connected to a common potential).

  The photodiode 51 is a light receiving element formed of silicon or the like through which an output current flows when irradiated with infrared light having a wavelength of about 3 microns or less that passes through the top plate 1, and can receive infrared light emitted from the cooking vessel 2. Provided in position. The operational amplifier 52 constitutes a current conversion circuit and an amplifier circuit.

  The current generated by the photodiode 51 is amplified by the operational amplifier 52 and output to the heating control unit 10 as an infrared detection signal 6 (corresponding to the voltage value V0) indicating the temperature of the cooking vessel 2.

  Infrared sensor 5 uses a thermistor that detects the temperature of cooking vessel 2 by detecting the heat of conduction through the top plate in contact with the back surface of top plate 1 in order to receive infrared rays emitted from cooking vessel 2. Compared with the method, thermal response is better.

  FIG. 3 shows an output characteristic graph of the infrared sensor 5 of the induction heating cooker according to the first embodiment of the present invention. In FIG. 3, the horizontal axis represents the bottom surface temperature of the cooking container 2, and the vertical axis represents the voltage value of the infrared detection signal 6 output from the infrared sensor 5.

  In the present embodiment, the infrared sensor 5 outputs the infrared detection signal 6 when the bottom surface temperature of the cooking container 2 is about 120 ° C. or higher so that the temperature of the fried food of the cooking container 2 can be controlled, and about 120 ° C. If it is less than the value, the amplification factor of the operational amplifier 52 is set so that the infrared detection signal 6 is not output.

  In this case, “not outputting the infrared detection signal 6” means not only outputting the infrared detection signal 6 but also not substantially outputting it, that is, the temperature calculation unit 11 changes the magnitude of the infrared detection signal 6. Based on outputting a weak signal that cannot substantially read the temperature change of the bottom surface of the cooking container 2. In addition, instead of making “the infrared detection signal 6 not output”, that is, the magnitude of the infrared detection signal 6 become substantially zero, the infrared detection signal 6 is set to a constant value that does not depend on the temperature of the bottom surface of the cooking container 2. You may make it the increase rate of the detection signal 6 become substantially zero, below predetermined temperature.

The output value of the infrared detection signal 6 is set so that the amplification value of the amplification circuit 52 is set so that the output value becomes larger than approximately zero when the signal output range, that is, when the temperature T of the cooking container 2 is about 120 ° C. or higher. Is done. When the temperature T of the cooking container 2 rises from about 120 ° C., the output value V0 of the infrared detection signal 6 becomes a value proportional to the X power of the temperature T of the cooking container 2 (for example, X = 6 to 9), It shows a non-linear monotonically increasing characteristic in which the slope of the increase increases as the temperature of the object to be heated increases, and the so-called power function (V0 = αT ^X ) (α is proportional to the increase in temperature T Constant).

  FIG. 4 is a temperature calculation graph of the temperature calculation unit of the induction heating cooker according to the first embodiment of the present invention.

  In FIG. 4, the output characteristic of the infrared sensor 5 used for the temperature calculation unit 11 to calculate the bottom surface temperature of the cooking container 2 from the voltage value of the infrared detection signal 6 is shown. In FIG. 4, the vertical axis represents the bottom surface temperature T of the cooking container 2, and the horizontal axis represents the voltage value of the infrared detection signal 6 output from the infrared sensor 5. When the output of the infrared sensor 5 is 0 mV, it is set to be calculated as about T10 (° C.), and is set so that a temperature equal to or higher than T10 (° C.) can be detected.

  The infrared sensor 5 of FIG. 4 uses, for example, a sensor having characteristics suitable for a temperature detection region of 120 ° C. to 220 ° C. that can be used for temperature adjustment of oil temperature in fried foods. The temperature change with respect to the change ΔV in the voltage value of the infrared detection signal 6 from when the voltage value of the infrared detection signal 6 is substantially 0 is ΔT1, and the infrared detection signal 6 when the voltage value of the infrared detection signal 6 is as large as V2. When the temperature change with respect to the voltage value change ΔV is ΔT2, ΔT1 >> ΔT2.

  When the temperature calculated by the temperature calculation unit 11 is equal to or higher than the predetermined temperature at the start of heating, the heating control unit 10 is when the temperature rise ΔT of the bottom surface temperature at a predetermined time from the start of heating is less than a predetermined threshold Td. Suppress heating output or stop heating. The heating control unit 10 is configured such that the calculated temperature of the bottom surface temperature calculating unit 11 is equal to or higher than the predetermined temperature Tt at the start of heating, and the temperature rise of the calculated temperature from the start of heating to the elapse of the predetermined time t1 is less than the predetermined threshold Td When the heating output is sometimes suppressed or the heating operation is stopped, the user is notified by sound or a display device.

  The operation and action of the induction heating cooker configured as described above will be described below.

  In FIG. 1, when the cooking container 2 is placed almost at the center on the heating coil 3 and the infrared sensor 5 receives infrared rays emitted from the bottom of the cooking container 2, the cooking container 2 is At normal temperature, the output of the infrared sensor 5 is approximately 0 mV from the output characteristics of the sensor of FIG. 3 and is calculated as T10 (° C.) from the characteristics of the temperature calculation unit 6. In the present embodiment, T10 (° C.) is about 120 ° C.

  When the operation unit 4 is operated and heating is started, a high-frequency current is supplied to the heating coil 3 and the bottom surface of the cooking vessel 2 is induction-heated. When the cooking container 2 is heated until a predetermined time t1 elapses from the start of heating, the temperature of the cooking container 2 rises and the output of the infrared sensor 5 becomes ΔV. The predetermined time t1 can be set to 75 seconds, for example. At this time, the temperature of the cooking vessel 2 is calculated to have risen to T1 (° C.). Thus, the temperature calculation part 11 calculates the temperature of the cooking container 2 from the characteristic of FIG. At this time, the temperature rise of the container 2 due to the heating for a predetermined time t1 is calculated as ΔT1.

  FIG. 5 is a diagram illustrating a state in which the placement position of the cooking container is inappropriate in the induction heating cooker according to Embodiment 1 of the present invention, and FIG. 6 is induction heating according to Embodiment 1 of the present invention. A characteristic graph of the infrared sensor when the placement position of the cooking container of the cooking device is inappropriate and infrared rays such as illumination are detected is indicated by a two-dot chain line A.

  In FIG. 5, when the center of the cooking vessel 2 is shifted from the center of the heating coil 3 and the infrared sensor 5 does not receive the infrared rays emitted from the bottom of the cooking vessel 2, the cooking vessel 2 is started before heating. When infrared rays contained in illumination or sunlight are received even at normal temperature, the infrared sensor 5 outputs a constant output voltage V2 that does not depend on the bottom surface temperature of the cooking vessel 2, as shown in FIG.

  Although V2 is about 400 mV in FIG. 6, it becomes larger if the ambient illuminance is brighter. V2 is calculated as T20 (° C.) from the characteristics shown in FIG. Also in this case, when the cooking container 2 is heated for a predetermined time t1, the temperature of the cooking container 2 rises by substantially ΔT1 (K) as in the case where the cooking container 2 is placed in the center.

  When the center of the cooking vessel 2 is shifted from the center of the heating coil 3 and the infrared sensor 5 does not receive infrared rays emitted from the bottom surface of the cooking vessel 2, the infrared sensor 5 is moved from the side of the cooking vessel 2. In some cases, the emitted infrared rays are detected. In this case, when an increase in the output voltage of ΔV is obtained in the output voltage of the infrared sensor 5, the temperature calculation unit 11 calculates that the bottom surface temperature of the cooking container 2 has increased by ΔT2 from the characteristics shown in FIG. When this ΔT2 is compared with the temperature change ΔT1 when the cooking container 2 is placed above the heating coil 3 so that the infrared ray radiated from the bottom surface of the cooking container 2 can be properly received by the infrared sensor 5, ΔT1 >> ΔT2. Therefore, the heating control unit 10 determines that ΔT2 is less than the threshold value Td, and suppresses heating output or stops heating.

  As described above, the heating control unit 10 has a predetermined temperature increase value ΔT when the temperature calculated by the bottom surface temperature calculation unit 11 is equal to or higher than the predetermined temperature Tt at the start of heating and the predetermined time t1 elapses after the heating starts. If it is equal to or greater than the threshold value Td, it can be determined that the placement position of the cooking container 2 is appropriate and the temperature of the bottom of the cooking container 2 can be detected, and it is safe to continue heating. If the calculated temperature is equal to or higher than the predetermined temperature Tt and the temperature rise value ΔT when heated until the predetermined time t1 elapses after the start of heating is less than the predetermined threshold Td, the cooking container 2 is placed at an inappropriate position and cooked. It can be determined that the temperature of the bottom of the container 2 cannot be detected, and heating is stopped because of danger.

  FIG. 7 is a flowchart showing the operation of the induction heating cooker according to the first embodiment of the present invention.

  In FIG. 7, when heating is started, it is determined whether or not the detected temperature Ts of the initial infrared sensor 5 is equal to or higher than a predetermined threshold value Tt (S701). When Ts ≧ Tt, heating is started with a predetermined output (S703). Next, it is determined whether or not a predetermined time has elapsed (S704), and when the predetermined time t1 has elapsed, it is determined whether or not the temperature rise value ΔT from the detected temperature Ts of the initial infrared sensor 5 is equal to or greater than a predetermined threshold Td (S705). ).

[Delta] T <mounting position of the T d if the cooking container 2 stops heating as inappropriate (S706), ΔT ≧ T d If mounting position continues to heat as appropriate.

  The predetermined threshold value Td is set to be smaller than the temperature rise value ΔT when the cooking container 2 is properly placed when the mass of the cooking container is large or when the amount of oil put into the cooking container is large. Has been. Therefore, even when the mass of the cooking container 2 is large or when the amount of oil put into the cooking container 2 is large, it is not erroneously determined that the placement position is inappropriate. In FIG. 4, the predetermined threshold value Tt is about 150 ° C. as an example. When the temperature of the cooking vessel 2 further rises from the predetermined threshold value Tt, ΔTt corresponding to the ΔT1 (the value corresponding to the ΔV is ΔVt) is the temperature when the output voltage of the infrared sensor 5 further increases by ΔVt. It is desirable to select a temperature that is at least 1.5 times the increase value ΔTt2. By doing so, it is possible to clearly detect that the output value of the infrared sensor 5 has risen. Further, it is desirable that ΔVt (corresponding to the predetermined threshold value Tt) be set larger than the maximum value that the infrared sensor 5 can receive with disturbance light when the cooking container 2 is properly placed.

As described above, in the present embodiment, the temperature rise of the calculated temperature from the start of heating until the predetermined time elapses only when the calculation result of the bottom surface temperature calculation unit at the start of heating is equal to or higher than the predetermined temperature . When the mass is large or when the amount of oil put into the cooking container is large, and the temperature rises below the calculated temperature from the start of heating when the cooking container is properly placed until the predetermined time elapses. By determining whether the placement position of the cooking container is inappropriate by judging whether it is less than the predetermined threshold set in the above, the chance of the cooking container being placed inappropriately and being heated is reduced and safety In addition, it is possible to accurately determine whether the placement position is inappropriate even when the mass of the cooking container is large or when the amount of food or oil put into the cooking container is large, and usability can be improved.

  The means described in this embodiment cooperates with hardware resources such as a CPU (or microcomputer), a RAM, a ROM, a storage / recording device, an electric / information device including an I / O, a computer, a server, and the like. You may implement with the form of the program to be made. In the form of a program, new functions can be distributed / updated and installed easily by recording them on a recording medium such as magnetic media or optical media or distributing them using a communication line such as the Internet.

  As described above, the induction heating cooker according to the present invention can accurately determine whether or not the mounting position of the cooking container is appropriate, and can be heated safely. It is effective as a device.

1 Top plate 2 Cooking container 3 Heating coil 3a Outer coil (heating coil)
3b Inner coil (heating coil)
3c Clearance (heating coil)
4 Operation part 5 Infrared sensor 9 Inverter circuit 10 Heating control part 11 Temperature calculation part (bottom surface temperature calculation part)
26 Notification Department

Claims (4)

A top plate formed of a material that transmits infrared rays;
A heating coil for induction heating the cooking vessel placed on the top plate by being supplied with a high-frequency current;
An inverter circuit for supplying the high-frequency current to the heating coil;
An infrared sensor that radiates from the bottom surface of the cooking container, detects infrared light transmitted through the top plate, and amplifies and outputs a detection signal corresponding to the bottom surface temperature;
A bottom surface temperature calculation unit that calculates the bottom surface temperature from the output of the infrared sensor;
Based on the output of the bottom temperature calculation unit, e Bei a heating control section for controlling the heating output of the inverter circuit,
The infrared sensor is configured such that the increase rate of the output of the infrared sensor is substantially zero when the temperature is lower than a predetermined temperature and increases as a power function when the temperature is equal to or higher than the predetermined temperature with respect to an increase in the bottom temperature of the cooking container. , The amplification factor of the amplifier is set,
The heating control unit is configured such that at the start of heating, the calculated temperature of the bottom surface temperature calculating unit is equal to or higher than the predetermined temperature, and the temperature increase of the calculated temperature from the start of heating until a predetermined time elapses is less than a predetermined threshold value. wherein when the large amount the suppression of heating output or have rows to stop the heating operation of the inverter circuit, the amount of oil the predetermined threshold to be put when the mass is large or the cooking container of the cooking container An induction heating cooker characterized by being set to be smaller than a temperature rise of the calculated temperature from the start of heating when the cooking container is properly placed until the predetermined time elapses . The heating control unit calculates the temperature of the bottom surface temperature calculation unit at the start of heating is not less the predetermined temperature or higher, and the temperature rise of the calculated temperature from the start of heating until a predetermined time has elapsed is less than the predetermined threshold 2. The induction heating cooker according to claim 1, wherein when the heating output is sometimes suppressed or the heating operation of the inverter circuit is stopped, a notification to that effect is given to the user. A top plate formed of a material that transmits infrared rays;
A heating coil for induction heating the cooking vessel placed on the top plate by being supplied with a high-frequency current;
An inverter circuit for supplying the high-frequency current to the heating coil;
An infrared sensor that radiates from the bottom surface of the cooking container, detects infrared light transmitted through the top plate, and amplifies and outputs a detection signal corresponding to the bottom surface temperature;
A bottom surface temperature calculation unit that calculates the bottom surface temperature from the output of the infrared sensor;
Based on the output of the bottom temperature calculation unit, e Bei a heating control section for controlling the heating output of the inverter circuit,
The infrared sensor has an increase rate of the output of the infrared sensor equal to or lower than a predetermined temperature with respect to an increase in the bottom surface temperature of the cooking container. Set the amplification factor of the amplifier so that it sometimes increases exponentially,
When the heating control unit calculates a temperature rise of the calculated temperature from the start of heating until a predetermined time elapses below a predetermined threshold when the calculated temperature of the bottom surface temperature calculating unit is equal to or higher than the predetermined temperature at the start of heating. wherein when the large amount the suppression of heating output or have rows to stop the heating operation of the inverter circuit, the amount of oil the predetermined threshold to be put when the mass is large or the cooking container of the cooking container Induction heating executed by a computer, comprising a step set to be smaller than a temperature rise of the calculated temperature from the start of heating when the cooking container is properly placed until a predetermined time elapses Program for cooker.   When the heating control unit calculates a temperature rise of the calculated temperature from the start of heating until a predetermined time elapses below a predetermined threshold when the calculated temperature of the bottom surface temperature calculating unit is equal to or higher than the predetermined temperature at the start of heating. 4. The program according to claim 3, further comprising a step of notifying a user to that effect when the heating output is suppressed or the heating operation of the inverter circuit is stopped.

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