JP5795931B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that selects and cooks a menu.

  As a conventional induction heating cooker, the temperature of the pan placed on the top plate is detected by a thermistor provided in close contact with the bottom surface of the top plate, and the heating output of the heating coil that heats the pan according to the output of the thermistor is detected. There is something to control and cook. The thermistor for detecting the temperature of the pan has a problem that the temperature response speed is slow because the temperature of the thermistor does not match the temperature of the pan because the top plate is interposed between the thermistor and the pan.

  Therefore, in Patent Document 1, instead of the thermistor, the temperature of the pan is directly captured using an infrared sensor, a menu is selected in advance, and heating is started, so that the temperature becomes suitable for charging the food. Disclosed is an induction heating cooker having an automatic cooking menu having a function of notifying that.

JP 2010-33981 A

  As described in paragraph 0040 of the document, the infrared sensor of Patent Document 1 has a property that it is difficult to detect infrared rays at a low temperature of about 150 ° C. or lower. It corresponded to the stir-fry cooking which heated at the above high temperature and high heat power.

  For this reason, when the cooking temperature is as low as 120 to 130 ° C., the infrared rays emitted from the pan cannot be detected sufficiently by the infrared sensor. For example, when cooking white sauce, cooking that requires careful heating is performed. At times, there was a problem that cooking had to be set manually.

The present invention has been made to solve the above-described problems, and is placed on the top plate by supplying a high-frequency current provided below the top plate and a top plate provided on the top surface of the main body. A heating coil for heating the pan, an inverter circuit for supplying a high-frequency current to the heating coil, an infrared sensor for detecting infrared rays emitted from the pan through the top plate, and menu setting means for inputting a cooking menu for cooking When controls the temperature and thermal adjusting means for setting the 120 to 130 ° C. as the temperature of the cooking menu set, the inverter circuit based on information from the infrared sensor and the set temperature 120 to 130 ° C. and control means, said control means, when the preheating of the pot, subjected to heat at a first predetermined high thermal increasing the temperature of the pan When the pan is kept warm, the pan is heated by repeating a second predetermined high thermal power that is lower than the first predetermined high thermal power and a predetermined low thermal power that lowers the temperature of the pan. The repeated heating performed at the time of the heat retention is performed when the temperature of the pan detected by the infrared sensor reaches a predetermined temperature corresponding to a set heating temperature from the second predetermined high thermal power to the predetermined low thermal power. The predetermined low thermal power is switched to the second predetermined high thermal power after continuing the predetermined low thermal power for a predetermined time stored in advance .

  According to the present invention, automatic cooking using an infrared sensor can be performed even at a low temperature of 120 to 130 ° C., for example, cooking with a lot of moisture such as white sauce can be automatically cooked.

The external appearance perspective view of the induction heating cooking appliance of one Example. The perspective view except the top plate of the induction heating cooking appliance of FIG. The principal part sectional drawing and control block diagram of the heating coil arrange | positioned at the right side of the induction heating cooking appliance of FIG. The enlarged view of the upper surface operation part and upper surface display part of the induction heating cooking appliance of FIG. Explanatory drawing of the control means 18 of FIG. The flowchart figure which shows the temperature control operation | movement in stir-fry setting. The time chart figure of the temperature control driving | running | working in a fried setting. The flowchart figure which shows the temperature control operation | movement in a fried egg setting. The time chart figure of the temperature control driving | operation in an egg-baking setting.

  An embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a built-in type that fits into the system kitchen will be described as an example, but a stationary heating cooker placed on the kitchen may be used.

  In FIG. 1, FIG. 2, the top plate 2 is arrange | positioned horizontally at the upper surface of the main body 1 of the induction heating cooking appliance. The top plate 2 is made of crystallized glass with a high heat resistance and has a thickness of about 4 mm, and a cooking container such as a pan 30 made of a magnetic material such as iron or a non-magnetic material such as aluminum is placed on the top plate 2. Below the top plate 2, annular heating coils 3 are arranged on the left and right and center rear in the upper part of the main body 1, respectively, and induction heating the pan 30 and the like placed on the top plate 2.

  Upper surface operation portions 7 a, 7 b, 7 c corresponding to the respective heating coils 3 are provided on the upper surface on the front surface side of the top plate 2, and the energization state of the heating coils 3 is set and operated. Corresponding to the upper surface operation parts 7a, 7b and 7c, upper surface display parts 8a, 8b and 8c are provided in the vicinity of the upper surface operation parts 7a, 7b and 7c, and the energization state of each heating coil 3 is determined. indicate. The upper surface operation unit 7a inputs the heating power and the like of the heating coil 3 on the right side of the main body 1, the upper surface operation unit 7b inputs the heating power and the like of the heating coil 3 at the center rear of the main body 1, and the upper surface operation unit 7c The heating power of the coil 3 is input.

  An intake port 4 opened upward is provided on the right side of the rear portion of the main body 1, and cooling air sucked from the intake port 4 by the fan (not shown) provided in the main body 1 is provided in the main body 1. It is cooled by flowing it through a control board (not shown), a heating coil 3 or the like provided on the board. An exhaust port 5 for exhausting the cooling air that has cooled the inside of the main body 1 is provided on the rear left side of the main body 1.

  A grill heating means 6 for grilling fish, pizza or the like is provided on the left side of the front surface of the main body 1. The grill heating means 6 has a box shape with an open front, a heating element such as a sheathed heater and a thermistor for detecting the internal temperature are provided in the internal cooking cabinet, and a handle 6a is attached to the front. The tray is closed by the grill door 6b, and a tray is accommodated therein.

  A main power switch 9 for supplying power to the main body 1 and a front operation unit 10 for inputting cooking conditions for the grill heating means 6 and the like are provided on the right front portion of the main body 1. The front operation unit 10 has a so-called kangaroo pocket shape in which the upper part of the operation panel 11 is tilted to the front side around a rotation axis provided below and the operation keys 12 are exposed upward.

  As shown in FIG. 2, the heating coils 3 arranged on the left and right and the central rear part are respectively an annular inner heating coil 3a and an annular outer heating coil 3c arranged with an annular gap 3b on the outside thereof. It consists of The reason why the gap 3b is provided in the heating coil 3 is to disperse the magnetic flux generated by the inner heating coil 3a and the outer heating coil 3c and to make the temperature of the pan 30 uniform. In addition, although each heating coil 3 was set as the structure which provides the clearance gap 3b, it is not limited to this in particular. For example, the structure which is set as the heating coil 3 without the gap | interval 3b which wound the inner side heating coil 3a and the outer side heating coil 3c without the gap may be sufficient.

  As shown in FIG. 3, the heating coil 3 is installed on a coil base 13, and the coil base 13 is biased toward the top plate 2 by a plurality of springs (not shown), and the heating coil 3 is 2 is configured so as to be substantially parallel to 2. The heating coil 3 employs a litz wire to suppress the skin effect, and a high frequency current of several tens of kHz and several hundreds V is supplied from an inverter circuit 19 described later, and a high frequency magnetic field is applied to the pan 30. Then, an eddy current is generated in the pan 30, and the pan 30 is heated by self-heating. The heating coil 3 disposed on the left side and the heating coil 3 disposed on the central rear part have the same configuration.

  Near the center of the inner heating coil 3a, an inner temperature sensor 15a of a temperature sensor constituted by a thermistor is attached in close contact with the lower surface of the top plate 2, and the temperature of the pan 30 is measured via the top plate 2. To do. Further, in the gap 3b of the heating coil 3, outer temperature sensors 15b, 15c, and 15d of a thermistor constituted by a thermistor are equidistant from the center of the heating coil 3 at an equal interval of about 120 degrees. (Not shown).

  The protrusions 16 provided on the outer peripheral edge of the coil base 13 are for maintaining a constant gap between the pan 30 placed on the top plate 2 and the heating coil 3. The distance is provided. The outer temperature sensors 15b, 15c, and 15d attached to the support member 14 are in close contact with the lower surface of the top plate 2 because the coil base 13 is biased by a spring in the direction of the top plate 2. The heating coil 3 disposed on the left side has a similar configuration.

  The outer temperature sensors 15b, 15c, and 15d are provided in the gap 3b of the heating coil 3, but are not particularly limited thereto. For example, a configuration may be provided in the vicinity of the outer periphery of the outer heating coil 3c, or in the vicinity of the outer periphery of the configuration of the heating coil 3 having no gap 3b in which the inner heating coil 3a and the outer heating coil 3c are wound without a gap. Further, the outer temperature sensors 15b, 15c, and 15d are not limited to three, and may be one, two, or three or more.

  Below the gap 3b of the heating coil 3, an infrared sensor 17 is provided for receiving infrared light emitted from the bottom surface of the pan 30 through the top plate 2 and measuring the temperature from the received infrared energy. . The infrared sensor 17 is a sensor using a thermal detection element, and its light receiving surface 17a is located at a position of the gap 3b of the heating coil 3 at a position about 35 mm away from the lower surface of the top plate 2 below the heating coil 3. Is provided. Although not shown, the light receiving surface 17a is provided with a lens, a filter, a light guide tube, and the like that limit the viewing angle of infrared rays to be measured. As shown in FIG. The viewing angle is detected by the temperature detection spot 17b. The infrared sensor 17 has a characteristic that when the temperature of the pan 30 is about 150 ° C. or less, the infrared energy radiated from the pan 30 cannot obtain a sufficient output.

  Next, heating control of the pan 30 will be briefly described with reference to FIG. Note that the control of the grill heating unit 6 and the control of the heating coil 3 at the center rear of the main body 1 are not directly related to the present embodiment, and thus are omitted in FIG. In FIG. 3, menu setting means 71 for inputting a cooking menu, temperature / heating power adjusting means 73 for setting a set temperature when the cooking menu is set, and heating power for heating the pan 30 are set in the upper surface operation unit 7 a. A heating power setting means 72 for performing cooking and a cutting / starting key 74 for performing cooking cutting / starting are provided. The operation information is input to the control means 18. The upper surface display unit 8a displays the input information of the upper surface operation unit 7a, the progress of cooking, and the like as display signals by the control means 18.

  The temperature detection signal of each temperature sensor of the inner temperature sensor 15a and the outer temperature sensors 15b, 15c and 15d provided in the heating coil 3 and the infrared sensor 17 provided below the heating coil 3 is input to the control means 18. The control means 18 controls the inverter circuit 19 according to the temperature detected by each temperature sensor, controls the high-frequency current flowing through the heating coil 3, and controls the heating of the pan 30. Further, the control means 18 controls the inverter circuit 19 based on the information set by the menu setting means 71, the thermal power setting means 72, and the temperature / thermal power adjustment means 73, thereby controlling the high-frequency current flowing through the heating coil 3 to control the pan. 30 is heated and controlled.

  The pan state determination means 20 receives the output signal of the infrared sensor 17 provided in the heating coil 3, determines from the detected temperature rise value whether or not the pot 30 being heated is suitable for heating, and the control means 18. To enter. In addition, although the inverter circuit 19 and the pan state determination means 20 are provided with two corresponding to the right and left heating coils 3, the control means 18 comprises the whole.

  Although the detailed operation of the pan state determination means 20 will not be described, the heating coil specific to the cooking menu is controlled in advance by experiments, and the heating coil is used for the difference in the state of the pan 30, the material of the pan 30 bottom, and the thickness at that time. The temperature rise value of the infrared sensor 17 provided in 3 is measured, and the correlation between the temperature rise value data and the state of the problematic pan 30 when the heating control specific to the cooking menu is performed is determined as data. As a reference, the pan state determination means 20 determines whether or not the pot 30 being heated is suitable for heating.

  The upper surface operation unit 7a and the upper surface display unit 8a will be described with reference to FIG. Since the contents of the upper surface operation unit 7c and the upper surface display unit 8c are the same as the contents of the upper surface operation unit 7a and the upper surface display unit 8a, description thereof is omitted. The upper surface display portion 8a is divided into a display 81a and a display 81b. The display 81a has the temperature / temperature when the thermal power input by the thermal power setting means 72, the cooking menu input by the menu setting means 71, and the cooking menu are set. A set temperature or the like input by the thermal power adjusting means 73 is displayed. In addition, the display 81b displays a process of heating the pan temperature to the set temperature when the menu for proper temperature cooking, which is one of automatic cooking, is selected, and “when preheating” is displayed, and when the pan temperature reaches the set temperature. The “appropriate temperature” that is displayed to inform the user of the timing of loading the ingredients is displayed.

  The thermal power that can be set by the thermal power setting means 72 is divided into four stages: a “hot fire” key 72a, a “low fire” key 72b, a “medium fire” key 72c, and a “high fire” key 72d, and the necessary thermal power can be input in one operation. In this way, keys are provided individually according to the thermal power. The standard of thermal power to be set is a maximum of 12 levels of thermal power, and the relationship between each thermal power and power consumption is equivalent to 0.1 kW for "1" stage, 0.2 kW for "2" stage, "3" ”Stage is 0.3 kW,“ 4 ”stage is 0.4 kW,“ 5 ”stage is 0.5 kW,“ 6 ”stage is 0.8 kW,“ 7 ”stage is 1.1 kW,“ 8 ”stage is 1. The 4 kW, “9” stage is 1.6 kW, the “10” stage is 2.0 kW, the “11” stage is 2.5 kW, and the “12” stage is 3.0 kW.

  As shown to Fig.4 (a), the display of the display 81a is a number which shows the standard of a thermal power. The relationship between the 12-stage number representing the thermal power and the four-stage thermal power that can be set by the thermal power setting means 72 is “1” for “slow fire”, “2”, “3”, “4”, “5” for “low fire”. , “Medium fire” is “6”, “7”, “8”, and “High fire” is “9”, “10”, “11”, “12”.

  When inputting a thermal power that cannot be input by the thermal power setting means 72, for example, a thermal power "9", the temperature / thermal power adjusting means 73 first sets the thermal power to "7" with the "medium fire" key 72c, and then the temperature / thermal power When the adjustment UP key 73b is pressed twice, the number indicating the heating power displayed on the display 81a is changed from "7" to "8", and from "8" to "9", and the heating power is changed to "9". It shows that. Incidentally, when the temperature / heating power adjustment DOWN key 73a is pressed next, the heating power can be lowered from “9” to “8”.

  Menu setting means 71 is for setting “cooking rice”, “fried food”, “boiled water”, “simmering” in the automatic cooking menu, “steak”, “stir-fried”, “eggaki”, etc. in the appropriate temperature cooking menu. When the menu setting means 71 is pressed, the menu is displayed on the display 81a. Each time the menu setting means 71 is pressed, the menu is switched and displayed. This selects the menu to be used. When the menu setting means 71 sets an appropriate temperature cooking menu such as “steak”, “stir-fried”, and “eggaki”, the temperature / heating power adjusting means 73 can adjust the set temperature as desired. Description of “cooking rice”, “fried food”, “boiled water”, and “boiled” in the automatic cooking menu is omitted.

  In the appropriate temperature cooking menu, the initial value of the set temperature varies depending on the menu, and “steak” is 220 ° C., “stir fry” is 200 ° C., and “eggaki” is 170 ° C. Moreover, the temperature adjustment range can adjust the range of 120 degreeC-250 degreeC by a 10 degreeC increment with all the menus.

  For example, in FIG. 4B, after selecting “stir-fry” for stir-cooking, the initial set temperature is “200” and increases to 250 ° C. in 10 ° C. increments every time the temperature / heating power adjustment UP key 73b is pressed. Can be set. In the figure, the number indicating the temperature is changed to “220”. Moreover, every time the temperature / heating power adjustment DOWN key 73a is pressed, the temperature can be set to 120 ° C. in steps of 10 ° C.

  In addition, when “Fried Egg” is selected in the fried egg cooking, the change can be made in the same manner. In FIG. 4C, “Fried Egg” is selected and the set temperature is changed from the initial set value “170” to the temperature / heat power adjustment DOWN. A display adjusted to “120” by pressing the key 73a is shown.

  FIG. 5 is a diagram for explaining the details of the temperature control by the control means 18. The operation switching means 91 for switching the operation of the control means 18 selects a temperature adjustment operation described later when the set temperature is equal to or higher than the threshold temperature 140 ° C. according to the set temperature set by the temperature / thermal power adjusting means 73, and the set temperature is the threshold temperature. When the temperature is lower than 140 ° C., a switching heating operation described later is selected.

  In the temperature adjustment operation, in order to maintain the average temperature of the pan 30 at the set temperature, when the temperature of the pan detected by the infrared sensor 17 is lower than the set temperature, the temperature of the pan detected by the infrared sensor 17 is set to a predetermined high heating power. When the temperature is higher than the set temperature, control is performed by switching the output of the high-frequency current supplied from the inverter circuit 19 to the heating coil 3 to a predetermined low heating power.

  In the switching heating operation, when the temperature of the pan detected by the infrared sensor 17 is higher than a predetermined temperature, the output of the high-frequency current supplied from the inverter circuit 19 to the heating coil 3 is switched from the predetermined high heating power to the predetermined low heating power. The timing for switching from the predetermined low heating power to the predetermined high heating power is determined by the timer time.

  For example, the predetermined temperature is set according to a cooking menu, a heating temperature, or the like, or the predetermined temperature is set to a lower limit temperature (for example, 150 ° C.) that can be detected by the infrared sensor 17 to change from a predetermined low heating power to a predetermined high heating power. By changing the timer time for switching long, the average temperature can be kept lower than the predetermined temperature by changing the amplitude of the temperature change of the pot 30 greatly.

  The predetermined high heating power is a high-frequency current output supplied from the inverter circuit 19 to the heating coil 3 in order to increase the temperature of the pan 30. The predetermined low thermal power is a high-frequency current output supplied from the inverter circuit 19 to the heating coil 3 in order to lower the temperature of the pot 30. The predetermined low thermal power is output from the inverter circuit 19. Zero states are also included.

  Further, the predetermined high heating power is set so as to decrease as the set temperature decreases. Specifically, the predetermined high thermal power is 2.0 kW at a preset temperature of 170 ° C. or higher, the predetermined high thermal power is 1.5 kW at the preset temperatures of 160 ° C., 150 ° C., and 140 ° C., and the predetermined high thermal power is 1.1 kW at the preset temperature of 130 ° C. At a set temperature of 120 ° C., the predetermined high thermal power is 0.5 kW. However, at the set temperature of 120 ° C., the predetermined high heating power is set to 0.8 kW before displaying and displaying “appropriate temperature”.

  In the temperature adjusting operation, after the infrared energy detected by the infrared sensor 17 is converted into a detected temperature, the temperature measuring means 92 compares the relationship between the temperature of the pan 30 and the set temperature, and the average temperature of the pan 30 becomes the set temperature. Thus, when the temperature of the pan 30 is lower than the set temperature, the high-frequency current output from the inverter circuit 19 is controlled so that the predetermined high heating power is obtained, and when the temperature of the pan 30 is higher than the set temperature, the predetermined low heating power is obtained. Thus, the high-frequency current output from the inverter circuit 19 is controlled.

  In the switching heating operation, after the infrared energy detected by the infrared sensor 17 is converted into a detected temperature, the temperature measuring means 92 compares the relationship between the temperature of the pan 30 and the set temperature, and the average temperature of the pan 30 becomes the set temperature. Thus, immediately after the start of heating, until the temperature detected by the infrared sensor 17 becomes equal to or higher than the predetermined temperature (for example, 150 ° C.), the output from the inverter circuit 19 is set to a predetermined high heating power in order to increase the temperature of the pan 30. The high frequency current output from the inverter circuit 19 is controlled so that when the temperature of the pan 30 becomes equal to or higher than the predetermined temperature (for example, 150 ° C.), the temperature of the pan 30 is lowered to a predetermined low heating power. Control. Further, at the same time when the predetermined high thermal power is switched to the predetermined low thermal power, the elapsed time after the switching is measured by the timer means 93, and the predetermined low thermal power previously stored in the timer time storage means 94 is measured. The predetermined low heating power is maintained in order to lower the temperature of the pan 30 until the maintenance time elapses, and the predetermined high heating power is used to increase the temperature of the pan after the elapsed time has elapsed. The high-frequency current output from the inverter circuit 19 is controlled.

  In the timer time storage means 94, as shown in FIG. 5, the set temperature set by the temperature / heating power adjusting means 73, the number of times of switching to a predetermined low heating power for each set temperature, and the number of times of switching to the predetermined low heating power. The time for maintaining the predetermined low heating power is stored. The time for maintaining the predetermined low heating power differs for each set temperature, and the longer the set temperature is, the longer the average temperature needs to be lowered. Further, the number of times of switching to a predetermined low heating power at the same set temperature becomes longer as the number of times is increased from the second time to the third time and the third time to the fourth time except the first time. Specifically, the first time is 10 seconds at a set temperature of 130 ° C., the second, third, fourth times are 7, 9, 11 seconds, the third time is 13 seconds, the second time is 120 ° C., the first time is 15 seconds, second, third, fourth times. Is set to 13, 16, 19 seconds, and the second and subsequent times are set to 22 seconds.

  The present embodiment is configured as described above. Next, an operation example of “stir-fry” and “egg-yaki” will be described in the menu for cooking at an appropriate temperature.

  First, automatic cooking at high temperature will be described with reference to FIG. 6 and FIG.

  When a user cooks “stir-fry” using the heating coil 3 on the right side of the main body 1, the main power switch 9 is first turned on to turn on the power, and the pan 30 (frying pan) used for heating is placed on the right side of the main body 1. Placed in the center of the heating coil 3 and operating the menu setting means 71 of the upper surface operation unit 7a while looking at the display 81a, as shown in FIG. 4B, "stir fry" is displayed on the display 81a. The set temperature initial value “200” displayed on the display 81a is changed to the desired set temperature “220” by operating the temperature / thermal power adjusting means 73. Next, the cut / start key 74 is pressed to start cooking, energize the heating coil 3, and put oil into the pan 30.

When the energization is started, as shown in FIG. 6, “Preheating” is displayed on the display 81b in Step 1, and the pot 30 is heated with a high heating power of 2.0 kW for the first 7 seconds after the energization is started in Step 2. Then, in step 3, the heating power is dropped to a low heating power of 0.5 kW and heated for 5 seconds. In step 4, the heating power is increased to 2.0 kW and heated. In step 5, when the temperature detected by the infrared sensor 17 reaches the set temperature T ₀ (200 ° C.), it is determined that the preheating is finished. In step 6, the pot state determination means 20 determines whether the pot 30 is suitable for heating. If it is suitable for heating, the process proceeds to step 7. In step 7, “appropriate temperature” is displayed on the display 81 b and informed, and then the process proceeds to heat retention in step 8 and temperature control is performed so that the temperature of the pan 30 is maintained at the set temperature T ₀ as an average temperature.

  In the heat retention in step 8, since the set temperature is 220 ° C., the operation switching means 91 selects the temperature adjustment operation and maintains the average temperature of the pan at the set temperature. The operation is controlled by switching the high-frequency current output from the inverter circuit 19 from a predetermined high heating power to a predetermined low heating power and from a predetermined low heating power to a predetermined high heating power according to the temperature of the pan 30 detected by the infrared sensor 17. Specifically, when the detection temperature of the infrared sensor 17 is 220 ° C. or more, the predetermined high heating power is changed from 2.0 kW to 0.3 kW of the predetermined low heating power, and when the detection temperature is 220 ° C. or less, the predetermined low heating power is 0.3. Change from 3 kW to 2.0 kW, which is a predetermined high heating power, and continue heating. Then, the user confirms that “appropriate temperature” is displayed on the display 81b, and puts the ingredients into the pan 30 to perform fried cooking. At this time, since the notification of the appropriate temperature, which is the timing at which the ingredients are added, is performed at the predetermined high heating power after performing the predetermined low heating power, the temperature drop of the pan when the ingredients are added is minimized. .

  Next, automatic cooking at low temperature will be described with reference to FIG. 8 and FIG.

  The user turns on the main power switch 9 to turn on the power to perform the fried egg cooking, puts the pot 30 (frying pan) used for heating in the center of the heating coil 3 on the right side of the main body 1, and operates the upper surface while viewing the display 81a. The menu setting means 71 of the unit 7a is operated to display “Fried egg” on the display 81a as shown in FIG. The temperature / heating power adjusting means 73 is operated to change the set temperature displayed on the display 81a to the desired “120”. Next, the cut / start key 74 is pressed to start cooking, energize the heating coil 3, and put oil into the pan 30.

  When energization is started, as shown in FIG. 8, “Preheating” is displayed on the display 81 b in Step 1. In step 2, heating is performed at a predetermined high heating power of 0.8 kW during preheating, and in step 3, when the temperature detected by the infrared sensor 17 reaches a predetermined temperature of 150 ° C., whether the pot 30 is heated properly by the pan state determination means 20 in step 4. If it is suitable for heating, the process proceeds to step 5. Heating at a predetermined low heating power of 0.1 kW in step 5, the timer means 93 of step 6 timed the first 15 seconds of maintaining the predetermined low heating power stored in the timer time storage means 94, and 15 seconds passed When it is determined that the preheating has been completed, “appropriate temperature” is displayed on the display 81b in step 7 for notification. Thereafter, the process proceeds to heat retention in step 8, and the temperature is controlled so that the average temperature of the temperature amplitude obtained by the switching heating operation becomes substantially the set temperature, and the pan 30 is maintained at the substantially set temperature.

  When "appropriate temperature" is displayed on the display 81b and the process proceeds to the heat retention in step 8, in step 8a, the high frequency current supplied from the inverter circuit 19 to the heating coil 3 by the control means 18 is supplied to the heating coil 3 by the control means 18 in order to reach the predetermined temperature 150 ° C. Energize at 0.5 kW. When the temperature reaches 150 ° C. shown in Step 8b, it switches to 0.1 kW of the predetermined low heating power shown in Step 8c. Then, the second number of times is 13 from the time data table for maintaining the predetermined low heating power with respect to the number of times of switching to the predetermined low heating power determined for each set temperature previously stored in the timer time storage means 94 by the timer means 93 in step 8d. Second, 16 seconds for the third time, 19 seconds for the fourth time, and 22 seconds for the fifth and subsequent times are selected and timed. For example, in the case of the second low thermal power time of 13 seconds, after the passage of 13 seconds, it is switched to a predetermined high thermal power of 0.5 kW, and is processed inside the control means 18 so as to repeat the switching of the thermal power so as to perform the switching heating operation. The output of the inverter circuit 19 is controlled. Then, the user confirms that “appropriate temperature” is displayed on the display 81b, and puts the ingredients into the pan 30 for cooking.

  Thus, the average temperature of the temperature of the pan 30 is obtained as the substantially set temperature by the switching heating operation of the lower limit predetermined temperature that can be detected by the infrared sensor 17 and the time for maintaining the predetermined low heating power. By maintaining the temperature, it is possible to set a set temperature in cooking at a low temperature such as fried eggs, and since the ingredients can be input at the temperature set by the user, it is possible to cook comfortably without feeling inconvenience during cooking.

  In addition, the time for maintaining the predetermined low thermal power is set so that the number of times of switching to the predetermined low thermal power becomes longer as the number of times increases from the second time to the third time and the third time to the fourth time except the first time. This is to prevent the temperature of the pan 30 from rising due to an increase in the average temperature of the ingredients placed in the pan 30 or the pan 30 by increasing the cooking time.

  In addition, the time for maintaining the initial predetermined low thermal power is long because it takes time for the temperature of the pan 30 to drop due to overshoot that occurs when the initial predetermined high thermal power is switched to the predetermined low thermal power. Is set.

  Also, if the volume and moisture content of the object to be heated are small, the time for heating at a predetermined high heating power is shortened, and if the capacity and moisture content of the object to be heated are increased, the time for heating at a predetermined high heating power is lengthened. Since the energization rate automatically changes according to the volume (amount) of the object to be heated, it is not necessary to set the capacity, and cooking can be performed satisfactorily.

  Furthermore, by differentiating the predetermined high heating power at the time of preheating and heat retention, preheating can be performed in a short time, and heat insulation can be cooked so as not to burn the object to be heated.

  Although the case where the set temperature is 120 ° C. has been described above, even in the switching heating operation where the set temperature is 130 ° C., the predetermined temperature for switching from the predetermined high thermal power to the predetermined low thermal power is the same as 150 ° C., and the predetermined low thermal power is maintained. It is possible by adjusting the time to do.

  According to the embodiment described above, automatic cooking can be performed using an infrared sensor even in cooking with a high moisture content (for example, white sauce) in a low temperature range of 120 to 130 ° C. without increasing the time spent for preheating. I can do it now.

DESCRIPTION OF SYMBOLS 1 Main body 2 Top plate 3 Heating coil 15 Temperature sensor 17 Infrared sensor 18 Control means 19 Inverter circuit 71 Menu setting means 73 Temperature / heating power adjustment means 91 Operation switching means 93 Timer means 94 Timer time storage means

Claims (1)

A top plate provided on the upper surface of the main body;
A heating coil provided below the top plate for heating the pan placed on the top plate by supplying a high frequency current;
An inverter circuit for supplying a high-frequency current to the heating coil;
An infrared sensor for detecting infrared radiation emitted from the pan through the top plate;
Menu setting means for inputting a cooking menu to be cooked;
A temperature / heating power adjusting means for setting 120 to 130 ° C. as the temperature of the set cooking menu;
And control means for controlling said inverter circuit on the basis of the information from the infrared sensor and the set temperature 120 to 130 ° C.,
The control means includes
During the preheating of the pan, heating is performed with a first predetermined high heating power that increases the temperature of the pan,
When the pan is kept warm, the pan is heated by repeating a second predetermined high thermal power that is lower than the first predetermined high thermal power and a predetermined low thermal power that lowers the temperature of the pan. Is,
The repeated heating performed during the heat retention is switched from the second predetermined high heating power to the predetermined low heating power when the temperature of the pan detected by the infrared sensor reaches a predetermined temperature corresponding to a set heating temperature, An induction heating cooker characterized in that the predetermined low heating power is switched to the second predetermined high heating power after continuing for a predetermined time stored in advance .