JP4996289B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that heats an object to be heated such as a pan or a pan using an electromagnetic induction heating coil.

  In recent years, induction heating cookers that inductively heat an object to be heated such as a pan with a heating coil have been widely recognized because of their excellent features of safety, cleanliness, and high efficiency. This type of induction heating cooker includes an infrared sensor that detects infrared energy emitted from the heated object in order to detect the temperature of the heated object. The infrared sensor receives infrared rays emitted from an object to be heated, which is incident from an infrared incident region of a top plate made of a material that can transmit infrared rays, and outputs a signal that changes according to the temperature of the object to be heated. . The induction heating cooker described in Patent Document 1 uses two infrared sensors to detect infrared energy in two different wavelength ranges, detects the temperature of the object to be heated from the relationship between these infrared energy, and Heating control of the heating unit is performed based on the detected temperature.

JP 2003-109736 A

  When the temperature of the object to be heated is high, the induction heating cooker described in Patent Document 1 determines that the heated object is in an overheated state and performs an emergency stop control for safety. By the way, during cooking, the pan may be shaken back and forth on the stove to move the place instantaneously. At this time, if the object to be heated comes off from the infrared incident region, the infrared energy from the object to be heated that the infrared sensor receives decreases, but the infrared sensor receives disturbance light such as visible light. As a result, the temperature of the object to be heated is determined to be higher than the actual temperature, and the protection function for preventing the overheated state operates to stop the heating.

  The present invention solves the above-mentioned problems, and provides an induction heating cooker that prevents malfunction even when the object to be heated is momentarily removed from the infrared incident region, and that achieves both safety and usability. The purpose is to do.

A first induction heating cooker according to the present invention includes a top plate for placing an object to be heated, a heating coil for induction heating the object to be heated by generating an AC magnetic field, and infrared rays emitted from the object to be heated. When the temperature of the object to be heated is detected based on the infrared sensor to be detected through the top plate and the output of the infrared sensor, and it is determined that the temperature of the object to be heated is equal to or higher than a predetermined temperature , determined to Ru and a control unit for controlling to stop the heating by the heating coil. Based on the output of the infrared sensor, the control unit determines a rapid increase in the temperature of the object to be heated, and determines that the temperature of the object to be heated is rapidly increasing. Even if it is above, while heating by a heating coil is continued and the rapid temperature rise is detected, after the elapse of a predetermined time, the temperature of the object to be heated is detected again, and the temperature of the object to be heated is equal to or higher than the predetermined temperature. If it is determined that heating by the heating coil is stopped or the heating output is reduced, and if it is determined that the temperature of the object to be heated is less than a predetermined temperature, heating by the heating coil is continued. The control unit determines that the temperature of the heated object is rapidly increased when the temperature of the heated object detected based on the output of the infrared sensor is equal to or higher than a limit temperature that is higher than a predetermined temperature. .

In the induction heating cooker of the, control unit, when the temperature of the object to be heated is detected based on the output of the infrared sensor is higher limit temperature or higher than the predetermined temperature, rapidly increases the temperature of the heated object is Instead of determining that the temperature of the object to be heated is not less than a predetermined rate of increase when the temperature increase rate of the object to be detected detected based on the output of the infrared sensor is higher than the predetermined temperature, You may judge.

  According to the induction cooking device of the present invention, usability can be improved without impairing safety.

  Embodiments of the present invention will be described below with reference to the drawings.

Embodiment [Configuration of Induction Heating Cooker]
FIG. 1 is a configuration diagram of an induction heating cooker according to an embodiment of the present invention. The induction heating cooker according to the present embodiment is provided with a top plate 2 on which an object to be heated 1 is placed and an upper surface facing the lower surface of the top plate 2 below the top plate 2 to generate an AC magnetic field and A heating coil for induction heating the heated object 1. In the present embodiment, the heating coil has a split winding configuration with an inner coil 3a and an outer coil 3b. Hereinafter, the inner coil 3a and the outer coil 3b are collectively referred to as a heating coil 3. The heating coil 3 does not need to have a split winding configuration. The object to be heated 1 is placed on the top surface of the top plate 2 at a position corresponding to the heating coil 3. The heating coil 3 is placed on a heating coil support 4 provided below the top plate 2. On the lower surface of the heating coil support 4, a ferrite 5 that concentrates the magnetic flux toward the back side of the heating coil 3 in the vicinity of the heating coil 3 is provided.

  In the top plate 2, a portion 6 facing the inner coil 3a and the outer coil 3b is formed of a material that can transmit infrared rays as an infrared incident region. Between the inner coil 3a and the outer coil 3b below the infrared incident region 6, a cylindrical light guide tube 7 having openings up and down is provided perpendicular to the upper surface of the heating coil 3. In addition, when the heating coil 3 is not a division | segmentation winding structure, the infrared rays incident area | region 6 can be provided in opening of the center part of the heating coil 3. FIG. In this case, the temperature of the higher temperature part of the object to be heated 1 can be detected by the infrared sensor 8 as close as possible to the winding of the heating coil 3. The infrared sensor 8 is provided to face the lower opening of the light guide tube 7. Infrared rays based on the temperature of the object to be heated 1 radiated from the bottom surface of the object to be heated 1 are incident from an infrared incident region 6 provided on the top plate 2, pass through the inside of the light guide tube 7, and the infrared sensor 8. Is received. The infrared sensor 8 detects received infrared rays and outputs a detection signal based on the detected infrared energy.

  Below the heating coil 3, the magnitude of the high-frequency current supplied to the heating coil 3 is controlled based on the inverter circuit 9 that supplies the high-frequency current to the heating coil 3 and the input from the operation unit 10 or the output of the infrared sensor 8. In order to do this, a control unit 11 is provided for controlling the inverter circuit 9 and for controlling the entire other induction heating cooker.

  Furthermore, the induction heating cooker of this Embodiment has the time measuring part 12 which measures the time while inputting the output information of the infrared sensor 8 from the control part 11. FIG. The control unit 11 detects the temperature of the object to be heated 1 based on the output of the infrared sensor 8 and supplies power to the heating coil 3 when determining that the temperature of the object to be heated 1 is equal to or higher than a predetermined value. If the temperature of the article to be heated 1 is rapidly increased, the temperature of the article to be heated 1 is invalidated and the power supply to the heating coil 3 is continued. The timer 12 measures the time after the controller 11 detects a sudden temperature rise of the article 1 to be heated, and notifies the controller 11 when the measured time reaches a predetermined time. After receiving this notification, the control unit 11 detects the temperature of the object to be heated 1 again, and if it determines that the temperature of the object to be heated 1 is equal to or higher than a predetermined value, it supplies power to the heating coil 3. When it stops and it judges that the temperature of the to-be-heated material 1 is less than predetermined value, the electric power supply to the heating coil 3 is continued.

[Operation of induction heating cooker]
Hereinafter, the basic operation of the induction heating cooker will be described. When the user inputs heating start, heating power setting, or the like from the operation unit 10, the control unit 11 controls the switching element of the inverter circuit 9 based on this input, and controls the amount of high-frequency current supplied to the heating coil 3. Control. When a high frequency current is supplied to the heating coil 3, a high frequency magnetic field is emitted from the heating coil 3, and the object to be heated 1 placed on the top plate 2 is induction heated.

  FIG. 2 is a diagram showing the relationship between the output of the infrared sensor 8 and the elapsed time when heating the article 1 to be heated. When the object to be heated 1 covers the infrared incident area 6, the output of the infrared sensor 8 gradually increases according to the heating time as indicated by the solid line 20. That is, the temperature of the object to be heated 1 gradually increases. In the present embodiment, the predetermined output V1 of the infrared sensor 8 is the output level when the temperature of the heated object 1 is the predetermined temperature T1 when the infrared sensor 8 normally detects the temperature of the heated object 1. It corresponds to. When the output of the infrared sensor 8 is equal to or higher than the predetermined output V1, that is, when the detected temperature of the infrared sensor 8 is equal to or higher than the predetermined temperature T1, the control unit 11 determines that the object to be heated 1 is in an overheated state, and ensures safety. Therefore, heating is stopped. On the other hand, when the object to be heated 1 is momentarily removed from the infrared incident area 6 by cooking a pot or the like during cooking, as shown by the broken line 21, disturbance light such as visible light is output from the infrared sensor 8 in the infrared incident area. When the infrared sensor 8 detects the incident light from 6, it suddenly increases and may exceed the predetermined output V <b> 1. Conventionally, when such a temperature change is detected, the heating is stopped for safety, but the induction heating cooker of the present embodiment continues the heating without stopping even in such a case. . Hereinafter, heating control of the induction heating cooker of the present embodiment will be described.

  In the induction heating cooker of the present embodiment, when the control unit 11 recognizes that the detection temperature of the infrared sensor 8 is high and the detection temperature is rising rapidly, the heated object 1 is moved from the infrared incident region 6. Since it is determined that there is a high possibility of the momentary disconnection, the detected temperature of the infrared sensor 8 is invalidated and heating is continued. And if the detection temperature of the infrared sensor 8 has fallen after the elapse of a predetermined time after detecting a sudden temperature change, the heated object 1 has returned to the infrared incident area 6 and the temperature of the heated object 1 is normal. However, if the temperature of the article to be heated 1 is still high, the heating is stopped to ensure safety.

  FIG. 3 is a flowchart showing a heating control process by the control unit 11 of the induction heating cooker according to the embodiment of the present invention. The control unit 11 inputs the detected temperature of the object to be heated 1 output from the infrared sensor 8, and the temperature increase rate ΔT from the detected temperature T at the current time t and the detected temperature T0 at the time t0 before the current time t. = T-T0 is calculated (S1). It is determined whether or not the detected temperature T of the infrared sensor 8 is equal to or higher than a predetermined temperature T1 (S2). When the temperature T of the article to be heated 1 is lower than the predetermined temperature T1 (No in S2), the temperature T and the temperature increase rate ΔT are measured again (S1), that is, the heating by the heating coil 3 is continued. On the other hand, when the temperature T of the article to be heated 1 is equal to or higher than the predetermined temperature T1 (Yes in S2), it is determined whether or not the detected temperature of the infrared sensor 8 is rapidly increased based on the temperature increase rate ΔT (S3). . Whether or not the temperature is rapidly increased is determined as follows. Specifically, when the temperature increase rate ΔT calculated in step S1 is equal to or higher than a predetermined increase rate, it is determined that the temperature of the article to be heated 1 is rapidly increasing. Alternatively, when the detected temperature T of the infrared sensor 8 is equal to or higher than the limit temperature that cannot be reached as the detected temperature of the article 1 to be heated, it may be determined that the temperature is rapidly increased. The limit temperature is higher than the predetermined temperature T1. When the detection temperature of the infrared sensor 8 does not increase rapidly (No in S3), it is determined that the detection temperature T of the infrared sensor 8 is correct, the heating by the heating coil 3 is stopped, and the heated object 1 is heated. Overheating is prevented (S8). This is the case, for example, at time t3 in FIG.

  On the other hand, when the controller 11 detects in step S3 that the temperature of the infrared sensor 8 is rapidly rising (Yes in S3), the output of the infrared sensor 8 is due to ambient light, that is, It is determined that the heated object 1 has deviated instantaneously from the infrared incident region 6, and the heating state of the object to be heated 1 is continued without stopping the heating by the heating coil 3 and a signal is output to the time measuring unit 12. The timekeeping unit 12 receives the signal and starts timekeeping (S4). The time measuring unit 12 outputs a time-up signal indicating that the predetermined time has elapsed to the control unit 11 after a predetermined time has elapsed, for example, 3 seconds after starting the time measurement (Yes in S5). The control unit 11 receives the time-up signal and inputs the detection temperature T ′ of the infrared sensor 8 again (S6). It is determined whether or not the detected temperature T 'of the infrared sensor 8 is equal to or higher than a predetermined temperature T1 (S7). When the detected temperature T ′ of the infrared sensor 8 is lower than the predetermined temperature T1 (No in S7), it is determined that the heated object 1 is momentarily displaced from the infrared incident area 6 but is now back, and the infrared sensor 8 returns to the mode for monitoring the detected temperature. That is, the heating by the heating coil 3 is continued (S1, S2). On the other hand, when the temperature T ′ of the object to be heated 1 is still equal to or higher than the predetermined temperature T1 (Yes in S7), the object to be heated 1 remains displaced from the infrared incident region 6, or other high-temperature object 1 to be heated. Is determined to be placed, and heating by the heating coil 3 is stopped (S8).

  For example, in the case of the broken line 21 in FIG. 2, that is, the temperature T of the heated object 1 detected at time t1 is equal to or higher than the predetermined temperature T1 (Yes in S2), and the detection temperature of the infrared sensor 8 rapidly increases. (Yes in S3), it is determined that the article to be heated 1 has deviated from the infrared incident region 6, and heating by the heating coil 3 is continued (S4). When the detection temperature T ′ of the infrared sensor 8 is input again at time t2 after a predetermined time has elapsed from the time t1 (S6), the detection temperature T ′ of the infrared sensor 8 is T1 ′ (corresponding to V1 ′) and the predetermined temperature. It is less than T1 (No in S7), and heating by the heating coil 3 is continued (S1, S2).

  As described above, according to the present embodiment, the control unit 11 determines the temperature of the object to be heated 1 based on the output of the infrared sensor 8 that detects the infrared rays emitted from the object to be heated 1 through the top plate 2. When the temperature is detected and it is determined that the temperature of the object to be heated 1 is equal to or higher than the predetermined temperature T1, control is performed so as to stop the heating by the heating coil 3, and the temperature rise of the object to be heated 1 is detected with good responsiveness. Therefore, for example, in the case of stir-fried vegetables, the high temperature is maintained with high heating power, and the object to be heated 1 is prevented from being heated exceeding the oil ignition temperature even in cooking using a small amount of oil. Further, when the temperature of the object to be heated 1 is determined to be rapidly increased based on the output of the infrared sensor 8, and the temperature of the object to be heated 1 is determined to be rapidly increasing, the temperature of the object to be heated 1 is increased. Even if the temperature is equal to or higher than the predetermined temperature T1, since the heating by the heating coil 3 is continued, for example, even if the pan is shaken during the stir-fry cooking, the heating operation does not stop, so it is easy to use.

  In addition, the control unit 11 detects the temperature of the object to be heated 1 again after a lapse of a predetermined time after detecting a rapid temperature increase, and determines that the temperature of the object to be heated 1 is equal to or higher than the predetermined temperature. Since the heating by the heating coil 3 is stopped, it is safe because the heating operation is stopped after confirming that the high temperature state of the article to be heated 1 is continued.

  Moreover, when the control part 11 detects the temperature of the to-be-heated object 1 again after predetermined time passes after detecting a rapid temperature rise, and judges that the temperature of the to-be-heated object 1 is less than the predetermined temperature T1, Since the heating by the heating coil 3 is continued, it is confirmed that the high temperature of the article 1 to be heated is temporary due to the cooking operation such as the user's panning, and the heating operation is continued, so that the cooking performance is improved. It is easy to use.

  In the present embodiment, the current heating output of the heating coil 3 is continued in step S4 of FIG. 3, but the present invention is not limited to this. In step S4, the heating output of the heating coil 3 may be lowered from the current output value. Then, when returning to step S1 from step S7, you may control to return the heating output of the heating coil 3 to the original heating output.

  In the present embodiment, the current heating output of the heating coil 3 is stopped in step S8 of FIG. 3, but the present invention is not limited to this. In step S8, it may be detected that the temperature detected by the infrared sensor 8 has dropped below the predetermined temperature T1 after the heating is stopped, and the process returns to the original heating state and returns to step S1. In step S8, instead of stopping the heating, the heating output of the heating coil 3 may be reduced from the current output value. Thereafter, when it is detected that the detection temperature of the infrared sensor 8 has decreased below the predetermined temperature T1, the heating output of the heating coil 3 may be controlled to return to the original heating output. By automatically returning the heating operation, the substantial heating output is increased and the usability is improved.

  In the present embodiment, the same predetermined temperature T1 is used in step S2 and step S7 in FIG. 3, but the present invention is not limited to this. The predetermined temperature in step S6 may be lower or higher than the predetermined temperature in step S2.

  The induction heating cooker according to the present invention has an effect that both safety and usability can be achieved, and is useful for an induction heating cooker used in general households.

The block diagram of the induction heating cooking appliance by embodiment of this invention The figure which shows the relationship between the output of an infrared sensor when heating a to-be-heated object, and elapsed time The flowchart which shows the heating control process by the control part of the induction heating cooking appliance of embodiment of this invention

Explanation of symbols

1 Heated object 2 Top plate 3 Heating coil 4 Heating coil support 5 Ferrite 6 Infrared incident area 7 Light guide tube 8 Infrared sensor 9 Inverter circuit 10 Operation unit 11 Control unit 12 Timekeeping unit

Claims (4)

A top plate for placing an object to be heated;
A heating coil for inductively heating an object to be heated by generating an alternating magnetic field;
An infrared sensor for detecting infrared rays emitted from the object to be heated via the top plate;
Based on the output of the infrared sensor, the temperature of the object to be heated is detected, and when it is determined that the temperature of the object to be heated is equal to or higher than a predetermined temperature, it is determined that the object is overheated and heating by the heating coil is stopped. And a control unit for performing control,
The controller determines a rapid increase in the temperature of the object to be heated based on the output of the infrared sensor, and determines that the temperature of the object to be heated is rapidly increased. Even if the temperature is equal to or higher than the predetermined temperature, the heating by the heating coil is continued ,
Detect the temperature of the object to be heated again after a predetermined time after detecting a sudden temperature rise,
When it is determined that the temperature of the object to be heated is equal to or higher than the predetermined temperature, the heating by the heating coil is stopped or the heating output is reduced, and when the temperature of the object to be heated is determined to be lower than the predetermined temperature, The heating by the heating coil shall be continued,
When the temperature of the heated object detected based on the output of the infrared sensor is equal to or higher than a limit temperature that is higher than the predetermined temperature, the temperature of the heated object is rapidly increased. to decide,
An induction heating cooker characterized by that.   A top plate for placing an object to be heated;
  A heating coil for inductively heating an object to be heated by generating an alternating magnetic field;
  An infrared sensor for detecting infrared rays emitted from the object to be heated via the top plate;
  Based on the output of the infrared sensor, the temperature of the object to be heated is detected, and when it is determined that the temperature of the object to be heated is equal to or higher than a predetermined temperature, it is determined that the object is overheated and heating by the heating coil is stopped. And a control unit for performing control,
  The controller determines a rapid increase in the temperature of the object to be heated based on the output of the infrared sensor, and determines that the temperature of the object to be heated is rapidly increased. Even if the temperature is equal to or higher than the predetermined temperature, the heating by the heating coil is continued,
  Detect the temperature of the object to be heated again after a predetermined time after detecting a sudden temperature rise,
  When it is determined that the temperature of the object to be heated is equal to or higher than the predetermined temperature, the heating by the heating coil is stopped or the heating output is reduced, and when the temperature of the object to be heated is determined to be lower than the predetermined temperature, The heating by the heating coil shall be continued,
  The control unit determines that the temperature of the heated object is rapidly increased when the temperature increase rate of the heated object detected based on the output of the infrared sensor is equal to or higher than a predetermined increase rate;
An induction heating cooker characterized by that. 3. The control unit according to claim 1, wherein, when it is determined that the temperature of the object to be heated is rapidly increased, the control unit controls the heating output of the heating coil to be decreased and continues the heating. The induction heating cooker described. The control unit detects the temperature of the object to be heated again after a predetermined time has elapsed after detecting a sudden temperature increase, and determines that the temperature of the object to be heated is less than the predetermined temperature. It controls so that a heating output may be returned to the original heating output, The induction heating cooking appliance of Claim 3 characterized by the above-mentioned.

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