WO2013042287A1 - Induction heating cooker - Google Patents

Induction heating cooker Download PDF

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Publication number
WO2013042287A1
WO2013042287A1 PCT/JP2012/002446 JP2012002446W WO2013042287A1 WO 2013042287 A1 WO2013042287 A1 WO 2013042287A1 JP 2012002446 W JP2012002446 W JP 2012002446W WO 2013042287 A1 WO2013042287 A1 WO 2013042287A1
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WO
WIPO (PCT)
Prior art keywords
heating coil
load resistance
pan
power
detection means
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Application number
PCT/JP2012/002446
Other languages
French (fr)
Japanese (ja)
Inventor
野村　智
和裕 亀岡
Original Assignee
三菱電機株式会社
三菱電機ホーム機器株式会社
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Application filed by 三菱電機株式会社, 三菱電機ホーム機器株式会社 filed Critical 三菱電機株式会社
Priority to JP2013534568A priority Critical patent/JP5642289B2/en
Publication of WO2013042287A1 publication Critical patent/WO2013042287A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/062—Control, e.g. of temperature, of power for cooking plates or the like
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/05—Heating plates with pan detection means

Definitions

  • the present invention relates to an induction heating cooker including a plurality of heating coils.
  • a placement plate for placing a pan, an induction coil disposed below the placement plate, and a control for energization control of the induction coil An induction heating cooker comprising an apparatus and an operation unit for issuing an energization control command to the control device to the control device, wherein the induction coil includes an inner coil and an outer coil, and the inner coil And the outer coil is individually energized and controlled, and the inner coil and / or the outer coil is determined based on the determination result of the pot bottom determining means that determines the size of the pot bottom using the inner coil and the outer coil.
  • a coil energizing means for controlling energization to the outer coil for example, see Patent Document 1).
  • the present invention has been made to solve the above-described problems, and provides an induction heating cooker that has improved heating unevenness even for large-diameter pans.
  • An induction heating cooker includes a top plate on which a cooking container, which is an object to be heated, is placed, an inner heating coil disposed below the top plate, and an outer periphery of the inner heating coil.
  • An external heating coil provided, an inverter circuit for supplying high-frequency power to the internal heating coil and the external heating coil, power detection means for detecting input power to the inverter circuit or output power from the inverter circuit, and internal heating coil Output current detecting means for detecting the magnitude of the current flowing through the external heating coil, control means for driving and controlling the inverter circuit based on the detection values of the power detection means and the output current detecting means, and the internal heating coil and the external heating coil Load resistance detecting means for detecting each load resistance, and when the load resistance of the external heating coil detected by the load resistance detecting means is equal to or greater than a predetermined value.
  • the inverter circuit is controlled so as to increase the ratio of the current value flowing through the outer heating coil to the current value flowing through the inner heating coil as compared with the case where the load resistance of the outer heating coil is determined to be less than the predetermined value. is there.
  • the control means when the load resistance detecting means detects that the load resistance value of the outer heating coil is equal to or greater than a predetermined value, the control means includes a pan placed above the inner heating coil and the outer heating coil. It is judged that this is a large-diameter pan made of magnetic material that can produce a large heating output with a relatively small heating coil current, and the current value of the inner heating coil (effective) Since the inverter circuit is controlled so as to increase the ratio of the current value (effective value) of the external heating coil to the value), in the large-diameter pan, the temperature drop of the outer periphery relative to the center of the pan bottom is suppressed, and the center of the pan bottom and the outer periphery of the pan bottom A temperature difference can be made small and it can suppress that a pan bottom center part burns or a pan bottom outer peripheral part becomes raw-burning.
  • FIG. 1 It is a figure which shows the circuit structural example of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. It is a figure which shows the heating coil structural example of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. It is a figure which shows the positional relationship of the pan of the induction heating cooking appliance which concerns on Embodiment 1, and a heating coil.
  • FIG. It is a figure which shows the relationship between the inner coil load resistance and the outer coil load resistance of the induction heating cooking appliance which concerns on Embodiment 1, and a pan size.
  • It is a flowchart which shows the heating control process in the control means of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. 1 shows the circuit structural example of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. It is a figure which shows the heating coil structural example of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. It is a figure which shows the positional relationship of the pan of
  • FIG. 1 It is a flowchart which shows the internal heating coil output control process in the control means of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. 2 is a flowchart which shows the external heating coil output control process in the control means of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. It is a figure which shows the example of a relationship between the external coil load resistance value of the induction heating cooking appliance which concerns on Embodiment 1, and an external heating coil electric power distribution coefficient. It is a figure which shows the temperature distribution example of each size pan bottom of the induction heating cooking appliance which concerns on Embodiment 1.
  • FIG. It is a figure which shows the heating coil structure of the induction heating cooking appliance which concerns on Embodiment 2.
  • FIG. 1 shows the example of a relationship between the external coil load resistance value of the induction heating cooking appliance which concerns on Embodiment 1, and an external heating coil electric power distribution coefficient.
  • FIG. It is a figure which shows the temperature distribution example of each size pan bottom of the in
  • FIG. 2 It is a figure which shows the circuit structural example of the induction heating cooking appliance which concerns on Embodiment 2.
  • FIG. It is a figure which shows the positional relationship of the heating coil of the induction heating cooking appliance which concerns on Embodiment 2, and the pan bottom for every pan size.
  • FIG. It is a figure which shows another example of a circuit structure of the induction heating cooking appliance which concerns on Embodiment 2.
  • FIG. FIG. 1 is a diagram illustrating a circuit configuration example of the induction heating cooker according to Embodiment 1
  • FIG. 2 is a diagram illustrating a configuration example of a heating coil.
  • the induction heating cooker is connected to an AC power source 1, and the power supplied from the AC power source 1 is converted into DC power by DC power supply circuits 2a and 2b and supplied to inverter circuits 8a and 8b.
  • the DC power supply circuits 2a and 2b have the same configuration, and the inverter circuits 8a and 8b have the same configuration.
  • the DC power supply circuits 2a and 2b include rectifier diode bridges 3a and 3b that rectify AC power, reactors 4a and 4b, and smoothing capacitors 5a and 5b.
  • the DC power converted by the DC power supply circuits 2a and 2b is supplied to the inverter circuits 8a and 8b.
  • the input power input to the inverter circuits 8a and 8b is detected by the input current detection means 6a and 6b and the input voltage detection means 7a and 7b.
  • the power detection means of the present invention is constituted by the input current detection means 6a and 6b and the input voltage detection means 7a and 7b in the present embodiment.
  • the inverter circuits 8a and 8b are connected to a high potential side switching element (hereinafter referred to as upper switches 9a and 9b) and a low potential side switching connected in series between the DC buses output from the DC power supply circuits 2a and 2b.
  • Elements hereinafter referred to as lower switches 10a and 10b
  • upper diodes 11a and 11b connected in antiparallel to the upper switches 9a and 9b
  • lower diodes 12a and 12b connected in antiparallel to the lower switches 10a and 10b It consists of and.
  • the upper switches 9a and 9b and the lower switches 10a and 10b are alternately turned on / off by the drive circuits 13a and 13b to generate a high frequency voltage.
  • Load circuits 14a and 14b are connected to output points of the inverter circuits 8a and 8b.
  • the load circuits 14a and 14b are constituted by a series circuit of an inner heating coil 15a and an outer heating coil 15b and resonance capacitors 16a and 16b, and clamp diodes 17a and 17b connected in parallel to the resonance capacitors 16a and 16b.
  • the inner heating coil 15a and the outer heating coil 15b are disposed below the top plate 22 on which a cooking container (such as a pan) that is an object to be heated is placed.
  • the outer heating coil 15b is concentric with the inner heating coil 15a and is disposed outside the outer periphery thereof.
  • the clamp diodes 17a and 17b clamp the connection point potential of the internal heating coil 15a and the external heating coil 15b and the resonance capacitors 16a and 16b to the low potential side bus potential of the DC power supply.
  • the inner heating coil 15a is a heating coil that heats the center of the pan bottom of the pot 23 (small-diameter pan 231, medium-diameter pan 232, large-diameter pan 233, which will be described later), and the outer heating coil 15b is heated. It is a heating coil which heats the pan bottom outer periphery of a thing, and the output current which flows into each heating coil is detected by the output current detection means 18a and 18b.
  • the control means 19 performs the drive control of each inverter circuit 8a, 8b and fulfills the function of controlling the entire induction heating cooker. Based on the heating power instruction set by the user in the operation unit 20, the control means 19 uses the detected values from the input current detection means 6a, 6b and the input voltage detection means 7a, 7b and the external heating coil 15a and the external heating coil 15a. Each power of the heating coil 15b is controlled.
  • the power control of the inner heating coil 15a is controlled by fixing the switching frequency of the upper switch 9a and the lower switch 10a and further adjusting the duty of the upper switch 9a and the lower switch 10a.
  • the power control of the outer heating coil 15b is controlled by fixing the switching frequency of the upper switch 9b and the lower switch 10b and adjusting the duty of the upper switch 9b and the lower switch 10b.
  • a power control method that does not adjust the switching frequency of the inverter circuits 8a and 8b is desirable.
  • the impedance of load circuits 14a and 14b which will be described later, changes with the frequency, the load resistance values of the inner heating coil 15a and the outer heating coil 15b also change, and power distribution becomes complicated. It is.
  • the load resistance detection means 211 provided in the control means 19 includes the electric power of the inner heating coil 15a and the outer heating coil 15b detected by the input current detection means 6a and 6b and the input voltage detection means 7a and 7b.
  • the load resistance value of the inner heating coil 15a and the load resistance value of the outer heating coil 15b are detected from the currents flowing in the inner heating coil 15a and the outer heating coil 15b detected by the output current detection means 18a and 18b, respectively.
  • the heating coil load resistance value is determined by the loss (heat generation) due to the high-frequency current flowing through the heating coil and the induced eddy current generated by the magnetic flux generated by the high-frequency current interlinking the bottom of the pan placed on the heating coil.
  • FIG. 3 shows the positional relationship between the pan and the heating coil of the induction heating cooker according to Embodiment 1
  • FIG. 4 shows the load resistance value of the inner heating coil, the load resistance value of the outer heating coil, and the pan. It is a figure which shows the relationship between the presence or absence and pan size.
  • FIG. 3 shows a case where a small-diameter pan 231 having an outer diameter of about the inner heating coil 15a or less is placed on the top plate 22 above the heating coil, and (b) shows the internal heating on the top plate 22 above the heating coil.
  • the presence / absence of the pan (231, 232, 233) to be heated is determined by determining the input current value of the internal heating coil 15a detected by the input current detection means 6a, the input voltage detection means 7a, and the output current detection means 18a, the input The determination is made based on the internal heating coil resistance value (Rin) detected by the load resistance detecting means 211 using the voltage value and the output current value.
  • Rin internal heating coil resistance value
  • the load resistance value of the internal heating coil 15a becomes small.
  • the threshold value R0 of the internal heating coil load resistance value which is a reference for determining whether heating is possible, is set so that the pan is not heated.
  • the threshold value R0 varies depending on the number of turns of the copper wire of the heating coil, but is set to, for example, about several ⁇ (2 ⁇ to 5 ⁇ ).
  • the discrimination of the pan sizes of the small-diameter pan 231, the medium-diameter pan 232, the large-diameter pan 233, etc. is performed by the input of the external heating coil 15b detected by the input current detection means 6b, the input voltage detection means 7b, and the output current detection means 18b.
  • the current value, the input voltage value, and the output current value are used to make a determination based on the external heating coil load resistance value (Rout) detected by the load resistance detection unit 211.
  • Rout external heating coil load resistance value
  • the high-frequency magnetic flux generated by the high-frequency current flowing through the outer heating coil 15b does not link much with the pan bottom, and a slight induction vortex Since only current flows, power consumption is small, input power is small, and the load resistance value of the external heating coil 15b is also small.
  • the large-diameter pan 233 that covers the entire upper surface of the outer heating coil 15b as shown in FIG. 3C the power consumed by the eddy current at the bottom of the pan increases due to the high-frequency magnetic flux generated by the high-frequency current flowing through the outer heating coil 15b.
  • the skin depth through which eddy current flows becomes shallow, and the load resistance value increases.
  • the outer heating coil load resistance value (Rout) is larger than that when the small diameter pan 231 is placed. This is an intermediate value when the pan 233 is placed.
  • the second threshold value R2 of the external heating coil load resistance value for determining the large diameter pan 233 covering the entire surface above the heating coil 15b, and comparing the external heating coil load resistance value with the threshold values R1 and R2, the small diameter pan 231, large-diameter pan 233, medium-diameter pan 232, and non-magnetic large-diameter pan.
  • the threshold values R0, R1, and R2 vary depending on the number of turns of the coil, but have the following relationship.
  • R1 ⁇ R0 ⁇ R2 For example, the threshold value R1 is about 1.5 ⁇ , and the threshold value R2 is about 5.3 ⁇ .
  • FIG. 5 is a flowchart showing the heating control processing by the control means 19 of the induction heating cooker according to the present embodiment
  • FIG. 8 is a diagram showing the relationship between the external heating coil load resistance value and the external heating coil power distribution coefficient
  • FIG. It is a figure which shows the example of a pot bottom temperature distribution in each pot size.
  • FIG. 5 is a flowchart showing the entire heating control process
  • FIG. 6 is a flowchart showing the output control process of the inner heating coil 15a
  • FIG. 7 is a flowchart showing the output control process of the outer heating coil 15b.
  • the control means 19 determines whether or not there is a heating request such as a heating power setting from the operation unit 20 (step 1), and when there is a heating request, controls the drive circuit 13a to control the inverter.
  • the circuit 8a is driven, a high frequency voltage is applied to the load circuit 14a including the internal heating coil 15a, and the load resistance detection unit 211 detects the values detected by the input current detection unit 6a, the input voltage detection unit 7a, and the output current detection unit 18a.
  • a detection process of the load resistance value of the heating coil 15a is performed (step 2).
  • the obtained load resistance value of the internal heating coil 15a is compared with a predetermined value R0 (step 3).
  • the pot is determined from the relationship between the internal heating coil load resistance value of FIG. 23 is determined not to be placed, the drive of the inverter circuit 8a is stopped (step 4), and the process returns to the heating request waiting from the operation unit 20 (step 1).
  • step 3 If it is determined in step 3 that the load resistance value of the inner heating coil 15a is equal to or greater than the predetermined value R0 and there is a load from the relationship between the inner heating coil load resistance value of FIG.
  • the drive circuit 13b is controlled to drive the inverter circuit 8b, a high frequency voltage is applied to the load circuit 14b including the external heating coil 15b, and the detected values by the input current detecting means 6b, the input voltage detecting means 7b, and the output current detecting means 18b. Then, the load resistance detection means 211 detects the load resistance value of the external heating coil 15b (step 5).
  • the internal heating coil output control process detects the electric power to the internal heating coil 15a from the detection values by the input current detection means 6a and the input voltage detection means 7a (step 8-1). Then, the detected power and the designated power of the thermal power set by the operation unit 20 are compared as the target power (step 8-1). If the detected power is smaller, an output of a drive signal is output to increase the heating power. Increase the level (increase the duty of the upper switch 9a and the lower switch 10a) (step 8-3).
  • step 8-4 If the detected power is larger, decrease the output level of the drive signal to reduce the heating power (upper switch 9a and the lower switch 10a are reduced) (step 8-4), and when the detected power and the target power are substantially equal, the output level of the drive signal is maintained as it is.
  • the distribution of the bottom temperature of the small-diameter pan 231 that is the object to be heated is, for example, as shown in FIG.
  • the load resistance detection unit 211 uses the output current value detected by the output current detection unit 18a and the input power value detected by the input current detection unit 6a and the input voltage detection unit 7a. It is determined whether or not there is no load by detecting the load resistance value (step 9). When it is determined that there is no load, it is determined whether or not the instruction input from the operation unit 20 is heating stop (step 10). If the heating is not stopped, the process returns to step 8 to continue the internal heating coil heating control process. In Step 9, it is determined that there is no load, for example, when the user moves the pan or pan from the heating port during cooking and there is no pan above the inner heating coil 15a.
  • step 10 When it is determined in step 10 that heating is stopped and in step 9 it is determined that there is no load, the process proceeds to step 11 where the drive circuit 13a is controlled to stop outputting the drive signal to the inverter circuit 8a (step 11). ), The process returns to waiting for a heating request from the operation unit 20 (step 1).
  • Step 6 when the load resistance value of the external heating coil 15b is not less than R1 and less than R2, and when it is not less than R2, the external heating coil 15b is respectively determined from the relationship between the external heating coil load resistance value and the pan size in FIG. It is determined that a medium-sized pan 232 or the like whose pan bottom covers a part of the top of the pan is placed, and a large-diameter pan 233 whose pan bottom covers the entire upper portion of the outer heating coil 15b. To do. And when it determines with the medium diameter pan 232 etc. being mounted based on the relationship between the external heating coil load resistance value of FIG.
  • the inner heating coil 15a and the outer heating coil 15b When the inside / outside normal drive mode is set so that the heating density is substantially equal (step 12) and it is determined that the large-diameter pan 233 is placed, it is more than when the medium-diameter pan 232 is placed.
  • an external heating emphasis driving mode is set (step 13).
  • the heating density is (the output of the heating coil) / (the area of the portion facing the pan of the heating coil).
  • the specified heating power (Wall), the inner heating coil load resistance value (Rin), and the outer heating coil load resistance value (Rout) set by the operation unit 20 are used, and the inner heating coil 15a and the outer heating coil 15b are used.
  • A1 is an external heating coil power distribution coefficient at the time of normal heating inside and outside
  • A1 is a pan having a predetermined pan diameter (for example, a pan having an inner heating coil outer diameter greater than or equal to the outer heating coil outer shape and other than a large diameter pan).
  • step 15 an internal heating coil output control process is performed (step 15).
  • This inner heating coil output control process is equivalent to step 8 described above, and is controlled by comparing the inner heating coil target power (Win) set in step 12 or step 13 with the detected power, and the input current detecting means 6a, It is determined whether or not there is no load from the load resistance value of the inner heating coil detected by the load resistance detection means 211 from the detection values of the input voltage detection means 7a and output current detection means 18a (step 16).
  • a coil output control process (step 17) is performed. In step 16, it is determined that there is no load, for example, when the user moves the pan or pan from the heating port during cooking and there is no pan above the inner heating coil 15a.
  • the power to the external heating coil 15b is detected from the values detected by the input current detection means 6b and the input voltage detection means 7b (step 17-1).
  • the detected power is compared with the external heating coil target power (Wout) set in step 12 or 13 (step 17-2). If the detected power is smaller, the drive signal is increased to increase the heating power.
  • the output level is increased (step 17-3), and if the detected power is larger, the output level of the drive signal is decreased to decrease the heating power (step 17-4).
  • the detected power and the target power are substantially equal, the output level of the drive signal is maintained as it is.
  • the load resistance detection unit 211 detects the output current value detected by the output current detection unit 18b and the input power value detected by the input current detection unit 6b and the input voltage detection unit 7b. It is determined whether or not there is no load by detecting the load resistance value (step 18). When it is determined that there is no load, it is determined whether or not the instruction input from the operation unit 20 is heating stop (step 19). If the heating is not stopped, it is determined whether or not there is a heating power change instruction instructed from the operation unit 20 (step 20). If there is no change, the process returns to step 15 to continue the internal heating coil heating control process and the like.
  • step 18 it is determined that the outer heating coil 15b is unloaded, for example, when the heating is started, the small-diameter pan 231 is shifted from the center of the heating port (a portion of the pan is located above the outer coil 15b). Then, during cooking, the small-diameter pan 231 is returned to the center of the heating port, and there is no pan above the outer coil 15b. If there is an instruction to change the heating power in step 20, the process returns to step 14 to reset the inner heating coil target power (Win) and the outer heating coil target power (Wout).
  • Win inner heating coil target power
  • Wout outer heating coil target power
  • step 16 If it is determined in step 16 that there is no load, or if it is determined in step 19 that there is a heating stop instruction, the process proceeds to step 11 to stop driving signal output to the inverter circuits 8a and 8b. The process returns to waiting for the heating request (step 1). If no load is detected in the outer heating coil 15b in step 18, the process proceeds to step 7 so that a high-frequency current flows only in the inner heating coil 15a.
  • each pan size when the target power to the inner heating coil 15a and the outer heating coil 15b is set and controlled by the inner heating coil load resistance value (Rin) and the outer heating coil load resistance value (Rout).
  • An example of the pan bottom temperature distribution in is shown in FIG. 9A shows an example of temperature distribution when the small-diameter pan 231 is placed, and FIG. 9B shows an example of temperature distribution when the medium-diameter pan 232 is placed.
  • the pan bottom is not positioned above the external heating coil 15b, and the external heating coil load resistance value Rout becomes small (Rout ⁇ R1).
  • the coil target power (Wout) is 0, and the external heating coil 15b is not energized.
  • the pan bottom is located at a part above the external heating coil 15b, and the external heating coil load resistance value (Rout) is a predetermined value (first value).
  • the outer heating coil load resistance value (Rout) is equal to or greater than a predetermined value (second threshold value R2) (Rout ⁇ R2), it is determined that the large-diameter pan 233 is used, and the inner heating coil is compared with the case of the medium-diameter pan 232
  • the ratio of the outer heating coil heating density to the heating density of 15a is increased. That is, the ratio of the current value (effective value) of the outer heating coil 15b to the current value (effective value) of the inner heating coil 15a is increased.
  • the average heating density is (the heating output of the outer heating coil 15b) / (the area of the outer periphery of the pan (including the portion where there is no heating coil below)).
  • the control unit 19 sets the load resistance value of the external heating coil 15b to a predetermined value.
  • the inverter circuit 8a is controlled so as to increase the ratio of the current value flowing through the outer heating coil 15b to the current value flowing through the inner heating coil 15a as compared with the case where it is determined that the value is less than the value. That is, when the load resistance value of the outer heating coil 15b is greater than or equal to a predetermined value, the medium diameter pan is larger than the large diameter pan 233 where the pan placed on the top plate 22 is larger than the outer diameter of the outer heating coil 15b.
  • the ratio of the external heating coil current (inverter circuit output current for the external heating coil) to the internal heating coil current (internal heating coil inverter circuit output current) was increased. That is, since the ratio of the heating density of the outer heating coil 15b to the heating density of the inner heating coil 15a is increased, the temperature difference between the center of the pan bottom and the outer periphery of the pan bottom can be reduced. It is possible to obtain an induction heating cooker that does not easily cause raw burning at the outer periphery of the pan bottom.
  • the pan to be heated is a non-magnetic large-diameter pan having a small external heating coil load resistance value
  • the external heating coil current is easy to flow because the load resistance value of the external heating coil 15b is small, so no overcurrent flows.
  • the heated pan is limited to the large-diameter pan 233 having a large external heating coil load resistance value, and the heating load for increasing the heating density of the external heating coil 15b is limited to a small heating coil. Since high heating output can be performed with current, no overcurrent flows, so there is no need to limit the output current of the inverter circuit 8a, and the heating distribution by the inner heating coil 15a and the outer heating coil 15b is heated by the output current of the inverter circuit 8a. An induction cooking device that does not change according to the level (low to high heating power) can be obtained.
  • FIG. 10 is a diagram illustrating a configuration of a heating coil of the induction heating cooker according to the second embodiment
  • FIG. 11 is a diagram illustrating a circuit configuration example of the induction heating cooker according to the second embodiment
  • 12 is a diagram showing a positional relationship between the heating coil of the induction heating cooker according to the second embodiment and the pan bottom for each pan size
  • FIG. 13 shows the internal heating of the induction heating cooker according to the second embodiment.
  • FIG. 14 is a diagram showing the relationship between the coil load resistance value, the external heating coil load resistance value, and the pan size placed above the heating coil, and FIG. 14 shows the external heating coil load of the induction heating cooker according to the second embodiment. It is a figure which shows the relationship between resistance value / inner heating coil load resistance value, and an outer heating coil electric power distribution coefficient.
  • FIG. 10 a plurality of heating coils 15a, 15b1 to 15b4 are arranged below the top plate 22 on which a cooking container (such as a pan) to be heated is placed, as in the first embodiment.
  • the inner heating coil 15a is an inner heating coil that heats the center of the pan bottom, which is an object to be heated.
  • the four external heating coils 15b1 to 15b4 are a plurality of external heating coils arranged outside the outer periphery of the internal heating coil 15a so as to surround the internal heating coil 15a. As shown in FIG.
  • the inner heating coil 15a is connected to the inverter circuit 8a.
  • the outer heating coils 15b1 to 15b4 are connected in parallel to the output point of the inverter circuit 8b.
  • Reference numerals 24a and 24b denote output voltage detection means for detecting a high-frequency voltage output from the inverter circuits 8a and 8b and applied to the load circuits 14a and 14b.
  • Reference numerals 25a and 25b denote output voltage detection means 24a and 24b and output current detection means. This is output power detection means that integrates and generates the output power values of the inverter circuits 8a and 8b from the outputs of 18a and 18b.
  • the inverter circuit 8a is driven to apply a high frequency voltage to the load circuit 14a, and the output current detected by the output current detection means 18a and the output power value detected by the output power detection means 25a are obtained.
  • the heating coil resistance value Rin it is possible to determine whether or not a pan suitable for heating is placed above the inner heating coil 15a.
  • the internal heating coil resistance can be discriminated between the case where the proper pan is placed and the case where a small object such as a fork that is not heated is placed.
  • a value threshold R0 is set. The threshold value R0 varies depending on the number of turns of the copper wire of the heating coil, but is set to, for example, about several ⁇ (2 ⁇ to 5 ⁇ ).
  • FIG. 12 (a) there is a pan bottom only above the inner heating coil 15a, and a small-diameter pan 231 is placed above the four outer heating coils 15b1 to 15b4.
  • FIG. 12B shows a case where a medium-sized pan 232 is placed on the inner heating coil 15a and a part of the four outer heating coils 15b1 to 15b4 are covered with a pan bottom, as shown in FIG.
  • the large-diameter pan 233 covered with the pan bottom is placed on the inner heating coil 15a and the four outer heating coils 15b1 to 15b4 as shown in FIG. 12 (c)
  • the inverter circuit 8a is driven and output.
  • the external heating coil load resistance value calculated from the output current value I2 and the output power value W2 of the external heating coils 15b1 to 15b4 detected by the output current detection means 18b and the output power detection means 25b by driving the inverter circuit 8b.
  • Rin Rin
  • the first threshold value r1 of Rout / Rin is the same as when the small-diameter pan 231 (FIG. 12 (a)) where the pan bottom is not positioned at all above the outer heating coils 15b1 to 15b4 and when the outer heating coils 15b1 to 15b4 It sets so that the case where the medium diameter pan 232 (FIG.12 (b)) in which a pan bottom is located in a part above 15b4 is mounted can be discriminate
  • the external heating coil load resistance value with respect to the internal heating coil load resistance value is equal to or greater than a predetermined value (large-diameter pan).
  • the ratio of the heating density of the outer heating coil to the heating density of the inner heating coil is increased as compared with the case where the inner heating coil is less than the predetermined value (medium diameter pan) (the outer heating coil with respect to the amount of current flowing through the inner heating coil)
  • the inverter circuits 8a and 8b are controlled so as to increase the amount of current that is supplied to the inverter.
  • the internal heating coil target power and the external heating coil target power are set as described above and the inverter circuits 8a and 8b are controlled, when a pan suitable for heating is placed, the internal heating coil load resistance value
  • a high-frequency current is applied only to the inner heating coil 15a.
  • the ratio (Rout / Rin) is greater than or equal to r1 and less than r2
  • control is performed such that a high frequency current B1 times that of the inner heating coil 15a is supplied to the outer heating coils 15b1 to 15b4.
  • the outer heating coils 15b1 to 15b4 are controlled to pass a high frequency current B2 times (0 ⁇ B1 ⁇ B2) that of the inner heating coil 15a. Therefore, if the material is suitable for heating, the ratio of the magnitude of the high frequency current of the outer heating coil and the inner heating coil can be adjusted according to the pan size regardless of the material of the pan. Induction that increases the heating density of the external heating coil when there are more parts that are not heated by the external heating coil on the outer periphery, and suppresses the temperature difference between the center of the pan bottom and the outer periphery of the pan bottom regardless of the pan material A cooking device can be obtained.
  • FIG. 11 of the second embodiment an example in which a plurality of external heating coils 15b1 to 15b4 are connected in parallel is shown.
  • individual inverter circuits 8b1 to 8b4 are used.
  • the structure driven may be sufficient and the structure connected in series may be sufficient as shown in FIG.
  • a plurality of outer heating coils 15b1 to 15b4 are arranged adjacent to the periphery of the inner heating coil 15a, and are appropriate (suitable for heating) by the inner heating coil load resistance value Rin.
  • the presence / absence of the pan is determined, and the pan size is determined regardless of the pan material based on the ratio (Rout / Rin) of the inner heating coil load resistance value Rin and the outer heating coil load resistance value Rout, which is larger than the outer heating coil outer diameter.
  • the ratio of the external heating coil current (inverter circuit output current for the internal heating coil) to the internal heating coil current (inverter circuit output current for the internal heating coil) was increased for large-diameter pans larger than the diameter.

Abstract

In the present invention, when a cookware size detection means that detects the size of cookware has detected a piece of cookware having at least a predetermined size, the ratio of the value of the current of an outer heating coil that heats the outer peripheral portion of a cookware bottom to the value of the current of an inner heating coil that heats the central portion of a cookware bottom is caused to be greater than when a piece of cookware that is less than the predetermined size is detected, thus increasing the proportion of heating of the outer peripheral portion of the cookware bottom and reducing heating unevenness of the cookware bottom.

Description

誘導加熱調理器Induction heating cooker
　本発明は、複数の加熱コイルを備える誘導加熱調理器に関するものである。 The present invention relates to an induction heating cooker including a plurality of heating coils.
　従来の誘導加熱調理器においては、例えば、「鍋を載置するための載置プレートと、前記載置プレートの下方に配置された誘導コイルと、前記誘導コイルに対して通電制御するための制御装置と、前記誘導コイルに対する通電制御指令を前記制御装置に発令するための操作部とを備えてなる誘導加熱調理器であって、前記誘導コイルが内コイルと外コイルとからなり、前記内コイル及び前記外コイルは個別に通電制御され、前記内コイル及び前記外コイルを利用して鍋底の大きさを判定する鍋底判定手段と、前記鍋底判定手段の判定結果に基づき前記内コイル及び／又は前記外コイルに対する通電を制御するコイル通電手段とをさらに備える」ものがあった（例えば、特許文献１参照）。 In a conventional induction heating cooker, for example, “a placement plate for placing a pan, an induction coil disposed below the placement plate, and a control for energization control of the induction coil” An induction heating cooker comprising an apparatus and an operation unit for issuing an energization control command to the control device to the control device, wherein the induction coil includes an inner coil and an outer coil, and the inner coil And the outer coil is individually energized and controlled, and the inner coil and / or the outer coil is determined based on the determination result of the pot bottom determining means that determines the size of the pot bottom using the inner coil and the outer coil. And a coil energizing means for controlling energization to the outer coil (for example, see Patent Document 1).
特開２００４－１２７８２１号公報（請求項１）JP 2004-127721 A (Claim 1)
　上記特許文献１の技術では、鍋底の大きさを検出し、鍋底の大きさに合わせて通電するコイルを選択するので、効率の良い加熱を可能とするとともに回路の安全性を高めた誘導加熱調理器を得ることができる。
　しかし、加熱コイルの外径を超えるような大鍋に対しては、鍋の外周部の加熱がされず、鍋の中心部に対して外周部の温度が低くなり、温度むらが大きくなって、鍋の中心部の焦げ付きや鍋の周辺部の生焼けが生じる問題点があった。 In the technique of the above-mentioned patent document 1, since the size of the pan bottom is detected and a coil to be energized is selected in accordance with the size of the pan bottom, induction heating cooking that enables efficient heating and increases the safety of the circuit. Can be obtained.
However, for a large pan that exceeds the outer diameter of the heating coil, the outer periphery of the pan is not heated, the temperature of the outer peripheral portion is lower than the center of the pan, and the temperature unevenness is increased. There was a problem that the burnt part of the center of the pan and the burnt part of the peripheral part of the pan occurred.
　本発明は、上記のような課題を解決するためになされたもので、大径鍋に対しても加熱むらを改善した誘導加熱調理器を得るものである。 The present invention has been made to solve the above-described problems, and provides an induction heating cooker that has improved heating unevenness even for large-diameter pans.
　本発明に係る誘導加熱調理器は、被加熱物である調理容器を載置する天板と、この天板の下方に配設される内加熱コイルと、この内加熱コイルの外周の外側に配設される外加熱コイルと、内加熱コイルと外加熱コイルに高周波電力を供給するインバーター回路と、このインバーター回路への入力電力あるいはインバーター回路からの出力電力を検出する電力検出手段と、内加熱コイルと外加熱コイルに流れる電流の大きさを検出する出力電流検出手段と、電力検出手段および出力電流検出手段の検出値に基づきインバーター回路を駆動制御する制御手段と、内加熱コイルおよび外加熱コイルの負荷抵抗をそれぞれ検出する負荷抵抗検出手段とを備え、制御手段が、負荷抵抗検出手段により検出した外加熱コイルの負荷抵抗が所定値以上の場合に、外加熱コイルの負荷抵抗が所定値未満と判断した場合と比較して、内加熱コイルに流れる電流値に対する外加熱コイルに流れる電流値の比を大きくするようにインバーター回路を制御するものである。 An induction heating cooker according to the present invention includes a top plate on which a cooking container, which is an object to be heated, is placed, an inner heating coil disposed below the top plate, and an outer periphery of the inner heating coil. An external heating coil provided, an inverter circuit for supplying high-frequency power to the internal heating coil and the external heating coil, power detection means for detecting input power to the inverter circuit or output power from the inverter circuit, and internal heating coil Output current detecting means for detecting the magnitude of the current flowing through the external heating coil, control means for driving and controlling the inverter circuit based on the detection values of the power detection means and the output current detecting means, and the internal heating coil and the external heating coil Load resistance detecting means for detecting each load resistance, and when the load resistance of the external heating coil detected by the load resistance detecting means is equal to or greater than a predetermined value. In addition, the inverter circuit is controlled so as to increase the ratio of the current value flowing through the outer heating coil to the current value flowing through the inner heating coil as compared with the case where the load resistance of the outer heating coil is determined to be less than the predetermined value. is there.
　本発明は、負荷抵抗検出手段が外加熱コイルの負荷抵抗値が所定値以上であることを検出した場合には、制御手段は、内加熱コイルおよび外加熱コイルの上方に載置された鍋が、比較的小さい加熱コイル電流で大きい加熱出力が得られる磁性材質の大径鍋と判断し、外加熱コイルの負荷抵抗値が所定値未満の場合と比較して、内加熱コイルの電流値（実効値）に対する外加熱コイルの電流値（実効値）の比を大きくするようインバーター回路を制御するので、大径鍋において鍋底中心部に対する外周部の温度低下を抑えて鍋底中心部と鍋底外周部の温度差を小さくすることができ、鍋底中心部が焦げ付いたり、鍋底外周部が生焼けとなったりするのを抑制することができる。 In the present invention, when the load resistance detecting means detects that the load resistance value of the outer heating coil is equal to or greater than a predetermined value, the control means includes a pan placed above the inner heating coil and the outer heating coil. It is judged that this is a large-diameter pan made of magnetic material that can produce a large heating output with a relatively small heating coil current, and the current value of the inner heating coil (effective) Since the inverter circuit is controlled so as to increase the ratio of the current value (effective value) of the external heating coil to the value), in the large-diameter pan, the temperature drop of the outer periphery relative to the center of the pan bottom is suppressed, and the center of the pan bottom and the outer periphery of the pan bottom A temperature difference can be made small and it can suppress that a pan bottom center part burns or a pan bottom outer peripheral part becomes raw-burning.
実施の形態１に係る誘導加熱調理器の回路構成例を示す図である。It is a figure which shows the circuit structural example of the induction heating cooking appliance which concerns on Embodiment 1. FIG. 実施の形態１に係る誘導加熱調理器の加熱コイル構成例を示す図である。It is a figure which shows the heating coil structural example of the induction heating cooking appliance which concerns on Embodiment 1. FIG. 実施の形態１に係る誘導加熱調理器の鍋と加熱コイルの位置関係を示す図である。It is a figure which shows the positional relationship of the pan of the induction heating cooking appliance which concerns on Embodiment 1, and a heating coil. 実施の形態１に係る誘導加熱調理器の内コイル負荷抵抗・外コイル負荷抵抗と鍋サイズの関係を示す図である。It is a figure which shows the relationship between the inner coil load resistance and the outer coil load resistance of the induction heating cooking appliance which concerns on Embodiment 1, and a pan size. 実施の形態１に係る誘導加熱調理器の制御手段における加熱制御処理を示すフローチャートである。It is a flowchart which shows the heating control process in the control means of the induction heating cooking appliance which concerns on Embodiment 1. FIG. 実施の形態１に係る誘導加熱調理器の制御手段における内加熱コイル出力制御処理を示すフローチャートである。It is a flowchart which shows the internal heating coil output control process in the control means of the induction heating cooking appliance which concerns on Embodiment 1. FIG. 実施の形態１に係る誘導加熱調理器の制御手段における外加熱コイル出力制御処理を示すフローチャートである。It is a flowchart which shows the external heating coil output control process in the control means of the induction heating cooking appliance which concerns on Embodiment 1. FIG. 実施の形態１に係る誘導加熱調理器の外コイル負荷抵抗値と外加熱コイル電力配分係数の関係例を示す図である。It is a figure which shows the example of a relationship between the external coil load resistance value of the induction heating cooking appliance which concerns on Embodiment 1, and an external heating coil electric power distribution coefficient. 実施の形態１に係る誘導加熱調理器の各サイズ鍋底の温度分布例を示す図である。It is a figure which shows the temperature distribution example of each size pan bottom of the induction heating cooking appliance which concerns on Embodiment 1. FIG. 実施の形態２に係る誘導加熱調理器の加熱コイル構成を示す図である。It is a figure which shows the heating coil structure of the induction heating cooking appliance which concerns on Embodiment 2. FIG. 実施の形態２に係る誘導加熱調理器の回路構成例を示す図である。It is a figure which shows the circuit structural example of the induction heating cooking appliance which concerns on Embodiment 2. FIG. 実施の形態２に係る誘導加熱調理器の加熱コイルと、鍋サイズ毎の鍋底との位置関係を示す図である。It is a figure which shows the positional relationship of the heating coil of the induction heating cooking appliance which concerns on Embodiment 2, and the pan bottom for every pan size. 実施の形態２に係る誘導加熱調理器の内加熱コイル負荷抵抗値と外加熱コイル負荷抵抗値と加熱コイル上方に載置されている鍋サイズの関係を示す図である。It is a figure which shows the relationship between the internal heating coil load resistance value of the induction heating cooking appliance which concerns on Embodiment 2, an external heating coil load resistance value, and the pan size currently mounted on the heating coil. 実施の形態２に係る誘導加熱調理器の外加熱コイル負荷抵抗値／内加熱コイル負荷抵抗値と外加熱コイル電力配分係数との関係を示す図である。It is a figure which shows the relationship between the external heating coil load resistance value / internal heating coil load resistance value of an induction heating cooking appliance which concerns on Embodiment 2, and an external heating coil electric power distribution coefficient. 実施の形態２に係る誘導加熱調理器の別の回路構成例を示す図である。It is a figure which shows another circuit structural example of the induction heating cooking appliance which concerns on Embodiment 2. FIG. 実施の形態２に係る誘導加熱調理器のさらに別の回路構成例を示す図である。It is a figure which shows another example of a circuit structure of the induction heating cooking appliance which concerns on Embodiment 2. FIG.
実施の形態１．
　図１は、実施の形態１に係る誘導加熱調理器の回路構成例を示す図であり、図２は加熱コイルの構成例を示す図である。
　図１において、誘導加熱調理器は、交流電源１に接続されており、交流電源１から供給される電力は直流電源回路２ａ、２ｂで直流電力に変換され、インバーター回路８ａ、８ｂに供給される。直流電源回路２ａ、２ｂはそれぞれ同一の構成であり、インバーター回路８ａ、８ｂもそれぞれ同一の構成である。
　直流電源回路２ａ、２ｂは、交流電力を整流する整流ダイオードブリッジ３ａ、３ｂとリアクトル４ａ、４ｂおよび平滑コンデンサ５ａ、５ｂにより構成されている。直流電源回路２ａ、２ｂで変換された直流電力は、インバーター回路８ａ、８ｂへ供給される。そしてインバーター回路８ａ、８ｂへ入力される入力電力は、入力電流検出手段６ａ、６ｂと入力電圧検出手段７ａ、７ｂとによって検出される。本発明の電力検出手段は、本実施の形態ではこの入力電流検出手段６ａ、６ｂと入力電圧検出手段７ａ、７ｂとにより構成される。 Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a circuit configuration example of the induction heating cooker according to Embodiment 1, and FIG. 2 is a diagram illustrating a configuration example of a heating coil.
In FIG. 1, the induction heating cooker is connected to an AC power source 1, and the power supplied from the AC power source 1 is converted into DC power by DC power supply circuits 2a and 2b and supplied to inverter circuits 8a and 8b. . The DC power supply circuits 2a and 2b have the same configuration, and the inverter circuits 8a and 8b have the same configuration.
The DC power supply circuits 2a and 2b include rectifier diode bridges 3a and 3b that rectify AC power, reactors 4a and 4b, and smoothing capacitors 5a and 5b. The DC power converted by the DC power supply circuits 2a and 2b is supplied to the inverter circuits 8a and 8b. The input power input to the inverter circuits 8a and 8b is detected by the input current detection means 6a and 6b and the input voltage detection means 7a and 7b. The power detection means of the present invention is constituted by the input current detection means 6a and 6b and the input voltage detection means 7a and 7b in the present embodiment.
　インバーター回路８ａ、８ｂは、直流電源回路２ａ、２ｂから出力された直流母線間に直列に接続された、高電位側のスイッチング素子（以下、上スイッチ９ａ、９ｂと呼ぶ）と低電位側のスイッチング素子（以下、下スイッチ１０ａ、１０ｂと呼ぶ）と、上スイッチ９ａ、９ｂに逆並列に接続された上ダイオード１１ａ、１１ｂと、下スイッチ１０ａ、１０ｂに逆並列に接続された下ダイオード１２ａ、１２ｂとで構成されている。前記上スイッチ９ａ、９ｂと下スイッチ１０ａ、１０ｂは駆動回路１３ａ、１３ｂにより交互にオン／オフされて高周波電圧を発生している。 The inverter circuits 8a and 8b are connected to a high potential side switching element (hereinafter referred to as upper switches 9a and 9b) and a low potential side switching connected in series between the DC buses output from the DC power supply circuits 2a and 2b. Elements (hereinafter referred to as lower switches 10a and 10b), upper diodes 11a and 11b connected in antiparallel to the upper switches 9a and 9b, and lower diodes 12a and 12b connected in antiparallel to the lower switches 10a and 10b It consists of and. The upper switches 9a and 9b and the lower switches 10a and 10b are alternately turned on / off by the drive circuits 13a and 13b to generate a high frequency voltage.
　インバーター回路８ａ、８ｂの出力点には、負荷回路１４ａ、１４ｂが接続されている。負荷回路１４ａ、１４ｂは、内加熱コイル１５ａ、外加熱コイル１５ｂと共振コンデンサ１６ａ、１６ｂの直列回路と、前記共振コンデンサ１６ａ、１６ｂと並列に接続されたクランプダイオード１７ａ、１７ｂとで構成されている。内加熱コイル１５ａ、外加熱コイル１５ｂは、後述するように、被加熱物である調理容器（鍋など）を載置する天板２２の下方に配設される。さらに、外加熱コイル１５ｂは、内加熱コイル１５ａと同心で、その外周の外側に配設される。クランプダイオード１７ａ、１７ｂは、内加熱コイル１５ａ、外加熱コイル１５ｂと共振コンデンサ１６ａ、１６ｂの接続点電位を直流電源の低電位側母線電位にクランプする。このクランプダイオード１７ａ、１７ｂの働きにより、下スイッチ１０ａ、１０ｂが導通した状態では内加熱コイル１５ａ、外加熱コイル１５ｂに流れる電流は転流しない。なお、内加熱コイル１５ａは被加熱物である鍋２３（後述する小径鍋２３１、中径鍋２３２、大径鍋２３３）の鍋底中心部を加熱する加熱コイルであり、外加熱コイル１５ｂは被加熱物の鍋底外周部を加熱する加熱コイルであり、それぞれの加熱コイルに流れる出力電流は出力電流検出手段１８ａ、１８ｂにより検出される。 Load circuits 14a and 14b are connected to output points of the inverter circuits 8a and 8b. The load circuits 14a and 14b are constituted by a series circuit of an inner heating coil 15a and an outer heating coil 15b and resonance capacitors 16a and 16b, and clamp diodes 17a and 17b connected in parallel to the resonance capacitors 16a and 16b. . As will be described later, the inner heating coil 15a and the outer heating coil 15b are disposed below the top plate 22 on which a cooking container (such as a pan) that is an object to be heated is placed. Further, the outer heating coil 15b is concentric with the inner heating coil 15a and is disposed outside the outer periphery thereof. The clamp diodes 17a and 17b clamp the connection point potential of the internal heating coil 15a and the external heating coil 15b and the resonance capacitors 16a and 16b to the low potential side bus potential of the DC power supply. By the action of the clamp diodes 17a and 17b, the current flowing through the inner heating coil 15a and the outer heating coil 15b is not commutated when the lower switches 10a and 10b are in a conductive state. The inner heating coil 15a is a heating coil that heats the center of the pan bottom of the pot 23 (small-diameter pan 231, medium-diameter pan 232, large-diameter pan 233, which will be described later), and the outer heating coil 15b is heated. It is a heating coil which heats the pan bottom outer periphery of a thing, and the output current which flows into each heating coil is detected by the output current detection means 18a and 18b.
　制御手段１９は、各インバーター回路８ａ、８ｂの駆動制御を行うとともに、誘導加熱調理器全体を制御する機能を果たすものである。制御手段１９は、操作部２０においてユーザが設定した火力指示に基づき、入力電流検出手段６ａ、６ｂと入力電圧検出手段７ａ、７ｂとからの検出値を使用して検出した内加熱コイル１５ａおよび外加熱コイル１５ｂのそれぞれの電力を制御するようになっている。内加熱コイル１５ａの電力制御は、上スイッチ９ａと下スイッチ１０ａのスイッチング周波数を固定とし、さらに、上スイッチ９ａと下スイッチ１０ａのｄｕｔｙを調整することにより制御する。外加熱コイル１５ｂの電力制御も同様に、上スイッチ９ｂと下スイッチ１０ｂのスイッチング周波数を固定とし、さらに、上スイッチ９ｂと下スイッチ１０ｂのｄｕｔｙを調整することにより制御する。このように、インバーター回路８ａ、８ｂのスイッチング周波数を調整しない電力制御方法が望ましい。周波数を調整する電力制御方法では、後述する負荷回路１４ａ、１４ｂのインピーダンスが周波数とともに変化し、内加熱コイル１５ａ、外加熱コイル１５ｂの負荷抵抗値も変化してしまい、電力配分が煩雑になるからである。 The control means 19 performs the drive control of each inverter circuit 8a, 8b and fulfills the function of controlling the entire induction heating cooker. Based on the heating power instruction set by the user in the operation unit 20, the control means 19 uses the detected values from the input current detection means 6a, 6b and the input voltage detection means 7a, 7b and the external heating coil 15a and the external heating coil 15a. Each power of the heating coil 15b is controlled. The power control of the inner heating coil 15a is controlled by fixing the switching frequency of the upper switch 9a and the lower switch 10a and further adjusting the duty of the upper switch 9a and the lower switch 10a. Similarly, the power control of the outer heating coil 15b is controlled by fixing the switching frequency of the upper switch 9b and the lower switch 10b and adjusting the duty of the upper switch 9b and the lower switch 10b. Thus, a power control method that does not adjust the switching frequency of the inverter circuits 8a and 8b is desirable. In the power control method for adjusting the frequency, the impedance of load circuits 14a and 14b, which will be described later, changes with the frequency, the load resistance values of the inner heating coil 15a and the outer heating coil 15b also change, and power distribution becomes complicated. It is.
　また、制御手段１９内に設けられた負荷抵抗検出手段２１１は、入力電流検出手段６ａ、６ｂ、入力電圧検出手段７ａ、７ｂにより検出された内加熱コイル１５ａ、外加熱コイル１５ｂのそれぞれの電力と、出力電流検出手段１８ａ、１８ｂにより検出された内加熱コイル１５ａ、外加熱コイル１５ｂにそれぞれ流れる電流から、内加熱コイル１５ａの負荷抵抗値と外加熱コイル１５ｂの負荷抵抗値を検出するものである。なお、加熱コイル負荷抵抗値は、加熱コイルに流れる高周波電流と、その高周波電流により発生した磁束が加熱コイル上方に載置された鍋底に鎖交して発生する誘導渦電流による損失（発熱）により増減し、加熱コイルに対向する鍋底が広いほど大きくなる。内加熱コイル負荷抵抗値（Ｒｉｎ）、外加熱コイル負荷抵抗値（Ｒｏｕｔ）は下記式により求める。
　Ｒｉｎ＝（内加熱コイル電力値）／（内加熱コイル電流値）２
　　＝（インバーター回路８ａ：入力電流値×入力電圧値）／（内加熱コイル電流値）２　Ｒｏｕｔ＝（外加熱コイル電力値）／（外加熱コイル電流値）２
　　＝（インバーター回路８ｂ：入力電流値×入力電圧値）／（外加熱コイル電流値）２　 Further, the load resistance detection means 211 provided in the control means 19 includes the electric power of the inner heating coil 15a and the outer heating coil 15b detected by the input current detection means 6a and 6b and the input voltage detection means 7a and 7b. The load resistance value of the inner heating coil 15a and the load resistance value of the outer heating coil 15b are detected from the currents flowing in the inner heating coil 15a and the outer heating coil 15b detected by the output current detection means 18a and 18b, respectively. . The heating coil load resistance value is determined by the loss (heat generation) due to the high-frequency current flowing through the heating coil and the induced eddy current generated by the magnetic flux generated by the high-frequency current interlinking the bottom of the pan placed on the heating coil. Increase / decrease and become larger as the pan bottom facing the heating coil is wider. The inner heating coil load resistance value (Rin) and the outer heating coil load resistance value (Rout) are obtained by the following equations.
Rin = (inner heating coil power value) / (inner heating coil current value) 2
= (Inverter circuit 8a: input current value x input voltage value) / (inner heating coil current value) 2 Rout = (outer heating coil power value) / (outer heating coil current value) 2
= (Inverter circuit 8b: Input current value x Input voltage value) / (External heating coil current value) 2
　図３は、実施の形態１に係る誘導加熱調理器の鍋と加熱コイルの位置関係を示すものであり、図４は、内加熱コイルの負荷抵抗値・外加熱コイルの負荷抵抗値と、鍋の有無や鍋サイズとの関係を示す図である。
　図３において、（ａ）は加熱コイル上方の天板２２上に内加熱コイル１５ａ外径程度以下の小径鍋２３１を載置した場合、（ｂ）は加熱コイル上方の天板２２上に内加熱コイル１５ａ外径よりも大きく、外加熱コイル１５ｂ外径よりも小さい中径鍋２３２を載置した場合、（ｃ）は加熱コイル上方の天板２２上に外加熱コイル１５ｂ外径より大きい大径鍋２３３を載置した場合を示す。 FIG. 3 shows the positional relationship between the pan and the heating coil of the induction heating cooker according to Embodiment 1, and FIG. 4 shows the load resistance value of the inner heating coil, the load resistance value of the outer heating coil, and the pan. It is a figure which shows the relationship between the presence or absence and pan size.
In FIG. 3, (a) shows a case where a small-diameter pan 231 having an outer diameter of about the inner heating coil 15a or less is placed on the top plate 22 above the heating coil, and (b) shows the internal heating on the top plate 22 above the heating coil. When the medium-diameter pan 232 that is larger than the outer diameter of the coil 15a and smaller than the outer diameter of the outer heating coil 15b is placed, (c) is larger than the outer diameter of the outer heating coil 15b on the top plate 22 above the heating coil. The case where the pan 233 is mounted is shown.
　被加熱物である鍋（２３１、２３２、２３３）の有無の判別は、入力電流検出手段６ａ、入力電圧検出手段７ａ、出力電流検出手段１８ａにより検出された内加熱コイル１５ａの入力電流値、入力電圧値、出力電流値を用いて負荷抵抗検出手段２１１が検出した内加熱コイル抵抗値（Ｒｉｎ）により判別する。内加熱コイル１５ａの上方に加熱に適した鍋が載置されていた場合には、内加熱コイル１５ａに流れる高周波電流により生ずる高周波磁束により鍋に渦電流が生じて発熱し、電力を消費するので内加熱コイル１５ａへ高周波電流を供給するインバーター回路８ａへの入力電力が大きくなり、その結果、内加熱コイル１５ａの負荷抵抗値（Ｒｉｎ＝入力電力／出力電流２）が大きくなる。一方、内加熱コイル１５ａの上方に鍋が載置されていない無負荷状態の場合には、内加熱コイル１５ａに流れる高周波電流により生ずる高周波磁束が誘導する渦電流が流れる負荷がないので電力が消費されず、入力電力が小さくなって負荷抵抗値も小さくなるからである。なお、鍋が、アルミニウムや銅等の誘導加熱に適さない低抵抗の材質である場合に、内加熱コイル１５ａの負荷抵抗値が小さくなる。かかる鍋は加熱しないように、加熱可否を判断する基準である内加熱コイル負荷抵抗値の閾値Ｒ０を設定するものとする。閾値Ｒ０は加熱コイルの銅線の巻き数等により異なるが、例えば、数Ω程度（２Ω～５Ω）に設定する。 The presence / absence of the pan (231, 232, 233) to be heated is determined by determining the input current value of the internal heating coil 15a detected by the input current detection means 6a, the input voltage detection means 7a, and the output current detection means 18a, the input The determination is made based on the internal heating coil resistance value (Rin) detected by the load resistance detecting means 211 using the voltage value and the output current value. When a pan suitable for heating is placed above the inner heating coil 15a, eddy current is generated in the pan due to the high-frequency magnetic flux generated by the high-frequency current flowing through the inner heating coil 15a, and heat is consumed. The input power to the inverter circuit 8a that supplies a high-frequency current to the inner heating coil 15a increases, and as a result, the load resistance value (Rin = input power / output current 2) of the inner heating coil 15a increases. On the other hand, in a no-load state where no pan is placed above the inner heating coil 15a, there is no load through which eddy currents induced by the high-frequency magnetic flux generated by the high-frequency current flowing through the inner heating coil 15a are consumed, so that power is consumed. This is because the input power is reduced and the load resistance value is also reduced. In addition, when a pan is a low resistance material which is not suitable for induction heating, such as aluminum and copper, the load resistance value of the internal heating coil 15a becomes small. The threshold value R0 of the internal heating coil load resistance value, which is a reference for determining whether heating is possible, is set so that the pan is not heated. The threshold value R0 varies depending on the number of turns of the copper wire of the heating coil, but is set to, for example, about several Ω (2Ω to 5Ω).
　また、小径鍋２３１、中径鍋２３２、大径鍋２３３等の鍋サイズの判別は、入力電流検出手段６ｂ、入力電圧検出手段７ｂ、出力電流検出手段１８ｂにより検出される外加熱コイル１５ｂの入力電流値、入力電圧値、出力電流値を用いて、負荷抵抗検出手段２１１が検出する外加熱コイル負荷抵抗値（Ｒｏｕｔ）により判別する。図３（ａ）のように外加熱コイル１５ｂの上方に鍋底が位置しない小径鍋２３１については、外加熱コイル１５ｂに流れる高周波電流により生ずる高周波磁束が鍋底にあまり鎖交せず、わずかな誘導渦電流しか流れないので、電力消費が小さく、入力電力が小さくなって外加熱コイル１５ｂの負荷抵抗値も小さくなる。図３（ｃ）のように外加熱コイル１５ｂの上方の全面を覆う大径鍋２３３については、外加熱コイル１５ｂに流れる高周波電流により生ずる高周波磁束により鍋底の渦電流により消費される電力が大きくなり、特に磁性材質の鍋において渦電流の流れる表皮深さが浅くなって負荷抵抗値が大きくなる。また、外加熱コイル１５ｂの上方の一部を覆う中径鍋２３２が載置されている場合には、外加熱コイル負荷抵抗値（Ｒｏｕｔ）は、小径鍋２３１が載置された場合と大径鍋２３３が載置された場合の中間的な値となる。 In addition, the discrimination of the pan sizes of the small-diameter pan 231, the medium-diameter pan 232, the large-diameter pan 233, etc. is performed by the input of the external heating coil 15b detected by the input current detection means 6b, the input voltage detection means 7b, and the output current detection means 18b. The current value, the input voltage value, and the output current value are used to make a determination based on the external heating coil load resistance value (Rout) detected by the load resistance detection unit 211. As for the small-diameter pan 231 where the bottom of the pan is not located above the outer heating coil 15b as shown in FIG. 3A, the high-frequency magnetic flux generated by the high-frequency current flowing through the outer heating coil 15b does not link much with the pan bottom, and a slight induction vortex Since only current flows, power consumption is small, input power is small, and the load resistance value of the external heating coil 15b is also small. For the large-diameter pan 233 that covers the entire upper surface of the outer heating coil 15b as shown in FIG. 3C, the power consumed by the eddy current at the bottom of the pan increases due to the high-frequency magnetic flux generated by the high-frequency current flowing through the outer heating coil 15b. Particularly, in a magnetic material pan, the skin depth through which eddy current flows becomes shallow, and the load resistance value increases. Moreover, when the medium diameter pan 232 which covers a part above the outer heating coil 15b is placed, the outer heating coil load resistance value (Rout) is larger than that when the small diameter pan 231 is placed. This is an intermediate value when the pan 233 is placed.
　上記のことから、内加熱コイル負荷抵抗値（Ｒｉｎ）および外加熱コイル負荷抵抗値（Ｒｏｕｔ）により図４の関係を用いて、内加熱コイル１５ａおよび外加熱コイル１５ｂの上方に載置された鍋の有無と鍋サイズの判定が可能である。すなわち、本実施の形態では、内加熱コイル負荷抵抗値（Ｒｉｎ）が所定値Ｒ０より小さい場合には加熱すべき鍋が載置されていないと判断し、Ｒ０以上の場合には鍋が載置されていると判断する。また、加熱すべき鍋が外加熱コイル１５ｂ上方に無い小径鍋２３１と外加熱コイル１５ｂ上方の一部に存在する中径鍋２３２とを判別する第１の閾値Ｒ１と、中径鍋２３２と外加熱コイル１５ｂ上方の全面を覆う大径鍋２３３を判別する外加熱コイル負荷抵抗値の第２の閾値Ｒ２を設定し、外加熱コイル負荷抵抗値と閾値Ｒ１、Ｒ２を比較することにより、小径鍋２３１、大径鍋２３３、中径鍋２３２および非磁性大径鍋を判別する。閾値Ｒ０、Ｒ１、Ｒ２はコイルの巻き数等により変わるが、次の関係がある。
　Ｒ１＜Ｒ０＜Ｒ２
　例えば、閾値Ｒ１が１．５Ω程度、閾値Ｒ２が５．３Ω程度となる。 From the above, the pan placed above the inner heating coil 15a and the outer heating coil 15b using the relationship of FIG. 4 with the inner heating coil load resistance value (Rin) and the outer heating coil load resistance value (Rout). It is possible to determine the presence or absence and pan size. That is, in this embodiment, when the inner heating coil load resistance value (Rin) is smaller than the predetermined value R0, it is determined that the pan to be heated is not placed, and when it is equal to or greater than R0, the pan is placed. Judge that it has been. Further, a first threshold value R1 for discriminating between a small-diameter pan 231 in which the pan to be heated is not located above the outer heating coil 15b and a medium-diameter pan 232 present in a part above the external heating coil 15b, the medium-diameter pan 232 and the outside By setting the second threshold value R2 of the external heating coil load resistance value for determining the large diameter pan 233 covering the entire surface above the heating coil 15b, and comparing the external heating coil load resistance value with the threshold values R1 and R2, the small diameter pan 231, large-diameter pan 233, medium-diameter pan 232, and non-magnetic large-diameter pan. The threshold values R0, R1, and R2 vary depending on the number of turns of the coil, but have the following relationship.
R1 <R0 <R2
For example, the threshold value R1 is about 1.5Ω, and the threshold value R2 is about 5.3Ω.
　図５は本実施の形態に係る誘導加熱調理器の制御手段１９による加熱制御処理を示すフローチャート、図８は外加熱コイル負荷抵抗値と外加熱コイル電力配分係数の関係を示す図、図９は各鍋サイズにおける鍋底温度分布例を示す図である。図５は加熱制御処理全体を示すフローチャート、図６は内加熱コイル１５ａの出力制御処理を示すフローチャート、図７は外加熱コイル１５ｂの出力制御処理を示すフローチャートである。以下、これらのフローチャートを用いて、本実施の形態１における誘導加熱調理器の制御手段の動作について説明する。 FIG. 5 is a flowchart showing the heating control processing by the control means 19 of the induction heating cooker according to the present embodiment, FIG. 8 is a diagram showing the relationship between the external heating coil load resistance value and the external heating coil power distribution coefficient, and FIG. It is a figure which shows the example of a pot bottom temperature distribution in each pot size. FIG. 5 is a flowchart showing the entire heating control process, FIG. 6 is a flowchart showing the output control process of the inner heating coil 15a, and FIG. 7 is a flowchart showing the output control process of the outer heating coil 15b. Hereinafter, the operation of the control means of the induction heating cooker in the first embodiment will be described using these flowcharts.
　図５に示すように、まず、制御手段１９は、操作部２０から火力設定等の加熱要求の有無を判断し（ステップ１）、加熱要求があった場合には駆動回路１３ａを制御してインバーター回路８ａを駆動し、内加熱コイル１５ａを含む負荷回路１４ａに高周波電圧を印加し、入力電流検出手段６ａ、入力電圧検出手段７ａ、出力電流検出手段１８ａによる検出値から負荷抵抗検出手段２１１により内加熱コイル１５ａの負荷抵抗値の検出処理を行う（ステップ２）。その結果、得られた内加熱コイル１５ａの負荷抵抗値を所定値Ｒ０と比較し（ステップ３）、Ｒ０未満の場合には、図４の内加熱コイル負荷抵抗値と負荷の有無の関係から鍋２３が載置されていないと判断し、インバーター回路８ａの駆動を停止して（ステップ４）、操作部２０からの加熱要求待ち（ステップ１）に戻る。 As shown in FIG. 5, first, the control means 19 determines whether or not there is a heating request such as a heating power setting from the operation unit 20 (step 1), and when there is a heating request, controls the drive circuit 13a to control the inverter. The circuit 8a is driven, a high frequency voltage is applied to the load circuit 14a including the internal heating coil 15a, and the load resistance detection unit 211 detects the values detected by the input current detection unit 6a, the input voltage detection unit 7a, and the output current detection unit 18a. A detection process of the load resistance value of the heating coil 15a is performed (step 2). As a result, the obtained load resistance value of the internal heating coil 15a is compared with a predetermined value R0 (step 3). If the load resistance value is less than R0, the pot is determined from the relationship between the internal heating coil load resistance value of FIG. 23 is determined not to be placed, the drive of the inverter circuit 8a is stopped (step 4), and the process returns to the heating request waiting from the operation unit 20 (step 1).
　ステップ３において、内加熱コイル１５ａの負荷抵抗値が所定値Ｒ０以上で、図４の内加熱コイル負荷抵抗値と負荷の有無の関係から負荷ありと判断した場合には、ステップ５に移行し、駆動回路１３ｂを制御してインバーター回路８ｂを駆動し、外加熱コイル１５ｂを含む負荷回路１４ｂに高周波電圧を印加し、入力電流検出手段６ｂ、入力電圧検出手段７ｂ、出力電流検出手段１８ｂによる検出値から負荷抵抗検出手段２１１により外加熱コイル１５ｂの負荷抵抗値の検出処理を行う（ステップ５）。その結果、得られた外加熱コイル１５ｂの負荷抵抗値を所定値Ｒ１およびＲ２と比較し（ステップ６）、Ｒ１未満の場合には、図４の外加熱コイル負荷抵抗値と鍋サイズの関係から、外加熱コイル１５ｂの上方に鍋底が位置しない小径鍋２３１が載置されていると判断する。そして、図８の外加熱コイル負荷抵抗値と外加熱コイル電力配分係数の関係に基づき、外加熱コイル目標電力＝０として、駆動回路１３ａによりインバーター回路８ａのみを駆動して（ステップ７）、内加熱コイル１５ａの出力制御処理（ステップ８）を行う。 If it is determined in step 3 that the load resistance value of the inner heating coil 15a is equal to or greater than the predetermined value R0 and there is a load from the relationship between the inner heating coil load resistance value of FIG. The drive circuit 13b is controlled to drive the inverter circuit 8b, a high frequency voltage is applied to the load circuit 14b including the external heating coil 15b, and the detected values by the input current detecting means 6b, the input voltage detecting means 7b, and the output current detecting means 18b. Then, the load resistance detection means 211 detects the load resistance value of the external heating coil 15b (step 5). As a result, the load resistance value of the obtained external heating coil 15b is compared with the predetermined values R1 and R2 (step 6), and if it is less than R1, the relationship between the external heating coil load resistance value and the pan size in FIG. It is determined that the small-diameter pan 231 with the pan bottom not located above the outer heating coil 15b is placed. Then, based on the relationship between the external heating coil load resistance value and the external heating coil power distribution coefficient in FIG. 8, with the external heating coil target power = 0, only the inverter circuit 8a is driven by the drive circuit 13a (step 7). An output control process (step 8) of the heating coil 15a is performed.
　図６に示すように、内加熱コイル出力制御処理（ステップ８）は、入力電流検出手段６ａと入力電圧検出手段７ａによる検出値から内加熱コイル１５ａへの電力を検出し（ステップ８-１）、その検出電力と、操作部２０により設定された火力の指定電力を目標電力として比較し（ステップ８-２）、検出電力の方が小さい場合には、加熱電力を増大させるべく駆動信号の出力レベルを上げ（上スイッチ９ａと下スイッチ１０ａのｄｕｔｙを大きくし）（ステップ８－３）、検出電力の方が大きい場合には、加熱電力を減少させるべく駆動信号の出力レベルを下げ（上スイッチ９ａと下スイッチ１０ａのｄｕｔｙを小さくし）（ステップ８－４）、検出電力と目標電力が略同等である場合には、駆動信号の出力レベルをそのまま維持する。かかる内加熱コイル１５ａのみの通電状態のとき、被加熱物である小径鍋２３１の鍋底温度の分布は、例えば図９（ａ）に示すようになる。 As shown in FIG. 6, the internal heating coil output control process (step 8) detects the electric power to the internal heating coil 15a from the detection values by the input current detection means 6a and the input voltage detection means 7a (step 8-1). Then, the detected power and the designated power of the thermal power set by the operation unit 20 are compared as the target power (step 8-1). If the detected power is smaller, an output of a drive signal is output to increase the heating power. Increase the level (increase the duty of the upper switch 9a and the lower switch 10a) (step 8-3). If the detected power is larger, decrease the output level of the drive signal to reduce the heating power (upper switch 9a and the lower switch 10a are reduced) (step 8-4), and when the detected power and the target power are substantially equal, the output level of the drive signal is maintained as it is. When only the inner heating coil 15a is energized, the distribution of the bottom temperature of the small-diameter pan 231 that is the object to be heated is, for example, as shown in FIG.
　図５に戻り、次いで、出力電流検出手段１８ａの検出する出力電流値と、入力電流検出手段６ａと入力電圧検出手段７ａで検出される入力電力値から負荷抵抗検出手段２１１により内加熱コイル１５ａの負荷抵抗値を検出して無負荷か否かを判別し（ステップ９）、無負荷ではないと判断した場合には操作部２０からの指示入力が加熱停止か否かを判定し（ステップ１０）、加熱停止でなければステップ８へ戻って内加熱コイル加熱制御処理を継続する。ステップ９で無負荷と判断されるのは、例えば、使用者が調理中に鍋振りや鍋を加熱口から移動して、内加熱コイル１５ａの上方に鍋がない場合である。ステップ１０で加熱停止、また、ステップ９で無負荷であると判断した場合には、ステップ１１へ移行して駆動回路１３ａを制御してインバーター回路８ａへの駆動信号の出力を停止し（ステップ１１）、操作部２０からの加熱要求待ち（ステップ１）に戻る。 Returning to FIG. 5, next, the load resistance detection unit 211 uses the output current value detected by the output current detection unit 18a and the input power value detected by the input current detection unit 6a and the input voltage detection unit 7a. It is determined whether or not there is no load by detecting the load resistance value (step 9). When it is determined that there is no load, it is determined whether or not the instruction input from the operation unit 20 is heating stop (step 10). If the heating is not stopped, the process returns to step 8 to continue the internal heating coil heating control process. In Step 9, it is determined that there is no load, for example, when the user moves the pan or pan from the heating port during cooking and there is no pan above the inner heating coil 15a. When it is determined in step 10 that heating is stopped and in step 9 it is determined that there is no load, the process proceeds to step 11 where the drive circuit 13a is controlled to stop outputting the drive signal to the inverter circuit 8a (step 11). ), The process returns to waiting for a heating request from the operation unit 20 (step 1).
　ステップ６で、外加熱コイル１５ｂの負荷抵抗値がＲ１以上Ｒ２未満の場合、および、Ｒ２以上の場合には、図４の外加熱コイル負荷抵抗値と鍋サイズの関係からそれぞれ、外加熱コイル１５ｂの上方の一部を鍋底が覆う中径鍋２３２等が載置されている状態、および、外加熱コイル１５ｂの上方を全面的に鍋底が覆う大径鍋２３３が載置されている状態と判断する。そして、図８の外加熱コイル負荷抵抗値と外加熱コイル電力配分係数の関係に基づき、中径鍋２３２等が載置されていると判定した場合には、内加熱コイル１５ａおよび外加熱コイル１５ｂの加熱密度を略同等とする内外通常駆動モードを設定し（ステップ１２）、大径鍋２３３が載置されていると判断した場合には、中径鍋２３２が載置されている場合よりも外側の加熱密度を上げるべく、外加熱重視駆動モードを設定する（ステップ１３）。ここで、加熱密度とは、（加熱コイルの出力）／（加熱コイルの鍋に対向する部分の面積）である。 In Step 6, when the load resistance value of the external heating coil 15b is not less than R1 and less than R2, and when it is not less than R2, the external heating coil 15b is respectively determined from the relationship between the external heating coil load resistance value and the pan size in FIG. It is determined that a medium-sized pan 232 or the like whose pan bottom covers a part of the top of the pan is placed, and a large-diameter pan 233 whose pan bottom covers the entire upper portion of the outer heating coil 15b. To do. And when it determines with the medium diameter pan 232 etc. being mounted based on the relationship between the external heating coil load resistance value of FIG. 8 and an external heating coil electric power distribution coefficient, the inner heating coil 15a and the outer heating coil 15b When the inside / outside normal drive mode is set so that the heating density is substantially equal (step 12) and it is determined that the large-diameter pan 233 is placed, it is more than when the medium-diameter pan 232 is placed. In order to increase the outside heating density, an external heating emphasis driving mode is set (step 13). Here, the heating density is (the output of the heating coil) / (the area of the portion facing the pan of the heating coil).
　そして、操作部２０で設定された火力の指定電力（Ｗａｌｌ）と内加熱コイル負荷抵抗値（Ｒｉｎ）、外加熱コイル負荷抵抗値（Ｒｏｕｔ）を使用して、内加熱コイル１５ａと外加熱コイル１５ｂの目標電力（Ｗｉｎ：内加熱コイル目標電力、Ｗｏｕｔ：外加熱コイル目標電力）を、内外通常加熱モードの場合には、
Ｗｉｎ＝Ｗａｌｌ×Ｒｉｎ／（Ｒｉｎ＋Ｒｏｕｔ×Ａ１）
Ｗｏｕｔ＝Ｗａｌｌ×Ｒｏｕｔ×Ａ１／（Ｒｉｎ＋Ｒｏｕｔ×Ａ１）
に設定し、外重視加熱モードの場合には、
Ｗｉｎ＝Ｗａｌｌ×Ｒｉｎ／（Ｒｉｎ＋Ｒｏｕｔ×Ａ２）
Ｗｏｕｔ＝Ｗａｌｌ×Ｒｏｕｔ×Ａ２／（Ｒｉｎ＋Ｒｏｕｔ×Ａ２）
に設定し、駆動回路１３ａ、１３ｂを駆動する（ステップ１４）。ただし、Ａ１は内外通常加熱モード時の外加熱コイル電力配分係数であり、Ａ１は所定の鍋径（例えば、内加熱コイル外径以上、外加熱コイル外形未満の鍋で、大径鍋以外の鍋）の鍋底温度分布（加熱コイルが対向する鍋底部分の温度部分）が略均一となる値であり、Ａ２は（Ａ２＞Ａ１＞０）の関係にある（例えば、Ａ１＝１．０、Ａ２＝１．３）外重視加熱モード時の外加熱コイル電力配分係数である。 Then, the specified heating power (Wall), the inner heating coil load resistance value (Rin), and the outer heating coil load resistance value (Rout) set by the operation unit 20 are used, and the inner heating coil 15a and the outer heating coil 15b are used. Target power (Win: internal heating coil target power, Wout: external heating coil target power)
Win = Wall × Rin / (Rin + Rout × A1)
Wout = Wall × Rout × A1 / (Rin + Rout × A1)
Set to, and in the case of the heating mode that emphasizes outside,
Win = Wall × Rin / (Rin + Rout × A2)
Wout = Wall × Rout × A2 / (Rin + Rout × A2)
Then, the drive circuits 13a and 13b are driven (step 14). However, A1 is an external heating coil power distribution coefficient at the time of normal heating inside and outside, and A1 is a pan having a predetermined pan diameter (for example, a pan having an inner heating coil outer diameter greater than or equal to the outer heating coil outer shape and other than a large diameter pan). ) Of the pan bottom temperature distribution (temperature portion of the pan bottom portion facing the heating coil) is substantially uniform, and A2 has a relationship of (A2>A1> 0) (for example, A1 = 1.0, A2 = 1.3) It is an external heating coil power distribution coefficient in the externally important heating mode.
　次いで内加熱コイル出力制御処理を行う（ステップ１５）。この内加熱コイル出力制御処理は、前記ステップ８と同等であり、ステップ１２またはステップ１３で設定した内加熱コイル目標電力（Ｗｉｎ）と検出電力とを比較して制御し、入力電流検出手段６ａ、入力電圧検出手段７ａ、出力電流検出手段１８ａの検出値から負荷抵抗検出手段２１１で検出した内加熱コイル負荷抵抗値から無負荷か否か判定し（ステップ１６）、無負荷でない場合には外加熱コイル出力制御処理（ステップ１７）を行う。ステップ１６で無負荷と判断されるのは、例えば、使用者が調理中に鍋振りや鍋を加熱口から移動して、内加熱コイル１５ａの上方に鍋がない場合である。 Next, an internal heating coil output control process is performed (step 15). This inner heating coil output control process is equivalent to step 8 described above, and is controlled by comparing the inner heating coil target power (Win) set in step 12 or step 13 with the detected power, and the input current detecting means 6a, It is determined whether or not there is no load from the load resistance value of the inner heating coil detected by the load resistance detection means 211 from the detection values of the input voltage detection means 7a and output current detection means 18a (step 16). A coil output control process (step 17) is performed. In step 16, it is determined that there is no load, for example, when the user moves the pan or pan from the heating port during cooking and there is no pan above the inner heating coil 15a.
　図７に示すように、外加熱コイル出力制御処理（ステップ１７）は、入力電流検出手段６ｂと入力電圧検出手段７ｂによる検出値から外加熱コイル１５ｂへの電力を検出し（ステップ１７－１）、その検出電力とステップ１２またはステップ１３で設定した外加熱コイル目標電力（Ｗｏｕｔ）とを比較し（ステップ１７－２）、検出電力の方が小さい場合には加熱電力を増大させるべく駆動信号の出力レベルを上げ（ステップ１７－３）、検出電力の方が大きい場合には加熱電力を減少させるべく駆動信号の出力レベルを下げる（ステップ１７－４）。また、検出電力と目標電力が略同等である場合には、駆動信号の出力レベルをそのまま維持する。 As shown in FIG. 7, in the external heating coil output control process (step 17), the power to the external heating coil 15b is detected from the values detected by the input current detection means 6b and the input voltage detection means 7b (step 17-1). The detected power is compared with the external heating coil target power (Wout) set in step 12 or 13 (step 17-2). If the detected power is smaller, the drive signal is increased to increase the heating power. The output level is increased (step 17-3), and if the detected power is larger, the output level of the drive signal is decreased to decrease the heating power (step 17-4). When the detected power and the target power are substantially equal, the output level of the drive signal is maintained as it is.
　図５に戻り、次いで、出力電流検出手段１８ｂの検出する出力電流値と、入力電流検出手段６ｂと入力電圧検出手段７ｂで検出される入力電力値から負荷抵抗検出手段２１１により外加熱コイル１５ｂの負荷抵抗値を検出して無負荷か否かを判別し（ステップ１８）、無負荷ではないと判断した場合には操作部２０からの指示入力が加熱停止か否かを判定し（ステップ１９）、加熱停止でなければ操作部２０から指示された火力変更指示の有無を判断し（ステップ２０）、変更がなければステップ１５に戻って内加熱コイル加熱制御処理等を継続する。なお、ステップ１８において外加熱コイル１５ｂが無負荷と判別されるのは、例えば、加熱開始時に小径鍋２３１が加熱口の中心からずれて配置され（外コイル１５ｂの上方に鍋の一部がある）、その後、調理中に小径鍋２３１を加熱口の中心に戻し、外コイル１５ｂの上方に鍋がない状態となった場合である。ステップ２０で火力変更の指示があった場合には、ステップ１４まで戻って、内加熱コイル目標電力（Ｗｉｎ）と外加熱コイル目標電力（Ｗｏｕｔ）を設定しなおす。 Returning to FIG. 5, next, the load resistance detection unit 211 detects the output current value detected by the output current detection unit 18b and the input power value detected by the input current detection unit 6b and the input voltage detection unit 7b. It is determined whether or not there is no load by detecting the load resistance value (step 18). When it is determined that there is no load, it is determined whether or not the instruction input from the operation unit 20 is heating stop (step 19). If the heating is not stopped, it is determined whether or not there is a heating power change instruction instructed from the operation unit 20 (step 20). If there is no change, the process returns to step 15 to continue the internal heating coil heating control process and the like. In step 18, it is determined that the outer heating coil 15b is unloaded, for example, when the heating is started, the small-diameter pan 231 is shifted from the center of the heating port (a portion of the pan is located above the outer coil 15b). Then, during cooking, the small-diameter pan 231 is returned to the center of the heating port, and there is no pan above the outer coil 15b. If there is an instruction to change the heating power in step 20, the process returns to step 14 to reset the inner heating coil target power (Win) and the outer heating coil target power (Wout).
　ステップ１６で無負荷であると判定した場合や、ステップ１９で加熱停止指示と判断した場合には、ステップ１１へ移行してインバーター回路８ａ、８ｂへの駆動信号出力を停止し、操作部２０からの加熱要求待ち（ステップ１）に戻る。また、ステップ１８において外加熱コイル１５ｂで無負荷を検出した場合には、内加熱コイル１５ａのみに高周波電流を流すべくステップ７に移行する。 If it is determined in step 16 that there is no load, or if it is determined in step 19 that there is a heating stop instruction, the process proceeds to step 11 to stop driving signal output to the inverter circuits 8a and 8b. The process returns to waiting for the heating request (step 1). If no load is detected in the outer heating coil 15b in step 18, the process proceeds to step 7 so that a high-frequency current flows only in the inner heating coil 15a.
　上記のように、内加熱コイル負荷抵抗値（Ｒｉｎ）、外加熱コイル負荷抵抗値（Ｒｏｕｔ）により、内加熱コイル１５ａおよび外加熱コイル１５ｂへの目標電力を設定して制御した場合の各鍋サイズにおける鍋底温度分布の例を図９に示す。図９において、（ａ）は小径鍋２３１を載置した場合の温度分布例、（ｂ）は中径鍋２３２を載置した場合の温度分布例である。小径鍋２３１が載置された図９（ａ）の場合には、外加熱コイル１５ｂの上方に鍋底が位置せず、外加熱コイル負荷抵抗値Ｒｏｕｔが小さくなるため（Ｒｏｕｔ＜Ｒ１）、外加熱コイル目標電力（Ｗｏｕｔ）は０であり、外加熱コイル１５ｂには通電されない。中径鍋２３２が載置された図９（ｂ）の場合には、外加熱コイル１５ｂの上方の一部に鍋底が位置し、外加熱コイル負荷抵抗値（Ｒｏｕｔ）が所定値（第１の閾値Ｒ１）以上（Ｒｏｕｔ≧Ｒ１）となれば、内加熱コイル目標電力Ｗｉｎ（＝Ｗａｌｌ×Ｒｉｎ／（Ｒｉｎ＋Ａ１×Ｒｏｕｔ））、外加熱コイル目標電力Ｗｏｕｔ（＝Ｗａｌｌ×Ａ１×Ｒｏｕｔ／（Ｒｉｎ＋Ａ１×Ｒｏｕｔ））を設定し、内加熱コイル１５ａと外加熱コイル１５ｂに加熱電力を分配する。 As described above, each pan size when the target power to the inner heating coil 15a and the outer heating coil 15b is set and controlled by the inner heating coil load resistance value (Rin) and the outer heating coil load resistance value (Rout). An example of the pan bottom temperature distribution in is shown in FIG. 9A shows an example of temperature distribution when the small-diameter pan 231 is placed, and FIG. 9B shows an example of temperature distribution when the medium-diameter pan 232 is placed. In the case of FIG. 9A in which the small-diameter pan 231 is placed, the pan bottom is not positioned above the external heating coil 15b, and the external heating coil load resistance value Rout becomes small (Rout <R1). The coil target power (Wout) is 0, and the external heating coil 15b is not energized. In the case of FIG. 9B in which the medium-diameter pan 232 is placed, the pan bottom is located at a part above the external heating coil 15b, and the external heating coil load resistance value (Rout) is a predetermined value (first value). If the threshold value R1) is equal to or greater than (Rout ≧ R1), the inner heating coil target power Win (= Wall × Rin / (Rin + A1 × Rout)) and the outer heating coil target power Wout (= Wall × A1 × Rout / (Rin + A1 × Rout) )) Is set, and the heating power is distributed to the inner heating coil 15a and the outer heating coil 15b.
　また、外加熱コイル負荷抵抗値（Ｒｏｕｔ）が所定値（第２の閾値Ｒ２）以上（Ｒｏｕｔ≧Ｒ２）であれば大径鍋２３３と判断し、中径鍋２３２の場合と比べて内加熱コイル１５ａの加熱密度に対する外加熱コイル加熱密度の比を高くする。すなわち、内加熱コイル１５ａの電流値（実効値）に対する外加熱コイル１５ｂの電流値（実効値）の比を大きくする。図３（ｃ）の大径鍋２３３で中径鍋２３２と同等の加熱密度で内加熱コイル１５ａと外加熱コイル１５ｂから加熱すると、中径鍋２３２と比較して外加熱コイル１５ｂの外径外側の外加熱コイルに流れる高周波電流による誘導渦電流があまり流れない鍋底部分が広くなり、鍋底外周部の平均加熱密度が下がって図９（ｃ）のような鍋底温度分布となり、鍋底中心部と鍋底外周部の温度差が大きくなる。ここで、平均加熱密度とは、（外加熱コイル１５ｂの加熱出力）／（鍋外周部の面積（下に加熱コイルがない部分を含む））である。このように温度差が大きくなると、被調理物を外周部まで十分に加熱すれば鍋底中心部で焦げ付きが生じたり、中心部の被調理物が十分に加熱できた時点で加熱を止めれば外周部で生焼けが生じたりする。そこで、本実施の形態のように外加熱コイル加熱密度を高くすることにより、図９（ｄ）に示すように鍋底中心部と鍋底外周部の温度差を低減する。 Further, if the outer heating coil load resistance value (Rout) is equal to or greater than a predetermined value (second threshold value R2) (Rout ≧ R2), it is determined that the large-diameter pan 233 is used, and the inner heating coil is compared with the case of the medium-diameter pan 232 The ratio of the outer heating coil heating density to the heating density of 15a is increased. That is, the ratio of the current value (effective value) of the outer heating coil 15b to the current value (effective value) of the inner heating coil 15a is increased. When the large-diameter pan 233 in FIG. 3C is heated from the inner heating coil 15a and the outer heating coil 15b at a heating density equivalent to that of the intermediate-diameter pan 232, the outer-diameter outer side of the outer heating coil 15b is compared with the intermediate-diameter pan 232. The pot bottom where the induced eddy current due to the high-frequency current flowing in the outside heating coil does not flow so much widens, the average heating density at the outer periphery of the pot bottom decreases, and the pot bottom temperature distribution as shown in FIG. The temperature difference at the outer periphery increases. Here, the average heating density is (the heating output of the outer heating coil 15b) / (the area of the outer periphery of the pan (including the portion where there is no heating coil below)). When the temperature difference becomes large in this way, if the food to be cooked is heated sufficiently to the outer periphery, it will be burnt at the center of the pan bottom, or if the heating is stopped when the food at the center is sufficiently heated, the outer periphery In some cases, raw burning occurs. Therefore, by increasing the external heating coil heating density as in the present embodiment, the temperature difference between the center of the pan bottom and the outer periphery of the pan bottom is reduced as shown in FIG.
　本実施の形態では、上記のように、制御手段１９が、負荷抵抗検出手段２１１により検出した外加熱コイル１５ｂの負荷抵抗値が所定値以上の場合に、外加熱コイル１５ｂの負荷抵抗値が所定値未満と判断した場合と比較して、内加熱コイル１５ａに流れる電流値に対する外加熱コイル１５ｂに流れる電流値の比を大きくするようにインバーター回路８ａを制御するようにしたものである。つまり、外加熱コイル１５ｂの負荷抵抗値が所定値以上の場合である、天板２２に載置される鍋が外加熱コイル１５ｂの外径よりも大きい大径鍋２３３に対して、中径鍋２３２の場合と比較し、内加熱コイル電流（内加熱コイル用インバーター回路出力電流）に対する外加熱コイル電流（外加熱コイル用インバーター回路出力電流）の比を大きくした。すなわち、内加熱コイル１５ａの加熱密度に対する外加熱コイル１５ｂの加熱密度の比を大きくしたので、鍋底中心部と鍋底外周部の温度差を低減でき、被調理物の鍋底中心部での焦げ付きや、鍋底外周部での生焼けが生じ難い誘導加熱調理器を得ることができる。 In the present embodiment, as described above, when the load resistance value of the external heating coil 15b detected by the load resistance detection unit 211 is greater than or equal to a predetermined value, the control unit 19 sets the load resistance value of the external heating coil 15b to a predetermined value. The inverter circuit 8a is controlled so as to increase the ratio of the current value flowing through the outer heating coil 15b to the current value flowing through the inner heating coil 15a as compared with the case where it is determined that the value is less than the value. That is, when the load resistance value of the outer heating coil 15b is greater than or equal to a predetermined value, the medium diameter pan is larger than the large diameter pan 233 where the pan placed on the top plate 22 is larger than the outer diameter of the outer heating coil 15b. Compared with the case of H.232, the ratio of the external heating coil current (inverter circuit output current for the external heating coil) to the internal heating coil current (internal heating coil inverter circuit output current) was increased. That is, since the ratio of the heating density of the outer heating coil 15b to the heating density of the inner heating coil 15a is increased, the temperature difference between the center of the pan bottom and the outer periphery of the pan bottom can be reduced. It is possible to obtain an induction heating cooker that does not easily cause raw burning at the outer periphery of the pan bottom.
　また、加熱される鍋を外加熱コイル負荷抵抗値が小さい非磁性大径鍋にした場合は、外加熱コイル１５ｂの負荷抵抗値が小さく、外加熱コイル電流が流れやすいので、過電流が流れないようにインバーター回路８ａの出力電流に制限を設ける必要がある。その結果、内加熱コイル１５ａおよび外加熱コイル１５ｂによる加熱分布をインバーター回路８ａの出力電流の制限等により加熱レベル（低火力～高火力）に応じて変化させる必要がある。これに対し、本実施の形態では、加熱される鍋は、外加熱コイル１５ｂの加熱密度を高くする被加熱負荷を外加熱コイル負荷抵抗値の大きい大径鍋２３３に限っており、小さい加熱コイル電流で高加熱出力を行えるので、過電流が流れないためインバーター回路８ａの出力電流に制限を設ける必要がなく、内加熱コイル１５ａおよび外加熱コイル１５ｂによる加熱分布をインバーター回路８ａの出力電流で加熱レベル（低火力～高火力）に応じて変化させることがない誘導加熱調理器を得ることができる。 Further, when the pan to be heated is a non-magnetic large-diameter pan having a small external heating coil load resistance value, the external heating coil current is easy to flow because the load resistance value of the external heating coil 15b is small, so no overcurrent flows. Thus, it is necessary to limit the output current of the inverter circuit 8a. As a result, it is necessary to change the heating distribution by the inner heating coil 15a and the outer heating coil 15b according to the heating level (low heating power to high heating power) by limiting the output current of the inverter circuit 8a. On the other hand, in the present embodiment, the heated pan is limited to the large-diameter pan 233 having a large external heating coil load resistance value, and the heating load for increasing the heating density of the external heating coil 15b is limited to a small heating coil. Since high heating output can be performed with current, no overcurrent flows, so there is no need to limit the output current of the inverter circuit 8a, and the heating distribution by the inner heating coil 15a and the outer heating coil 15b is heated by the output current of the inverter circuit 8a. An induction cooking device that does not change according to the level (low to high heating power) can be obtained.
実施の形態２．
　本実施の形態２では、外加熱コイルを内加熱コイルの外周の外側に隣接して取り囲むように複数配置した構成の形態について説明する。
　図１０は、実施の形態２に係る誘導加熱調理器の加熱コイルの構成を示す図であり、図１１は本実施の形態２にかかる誘導加熱調理器の回路構成例を示す図であり、図１２は本実施の形態２に係る誘導加熱調理器の加熱コイルと、鍋サイズ毎の鍋底との位置関係を示す図であり、図１３は本実施の形態２に係る誘導加熱調理器の内加熱コイル負荷抵抗値と外加熱コイル負荷抵抗値と加熱コイル上方に載置されている鍋サイズの関係を示す図であり、図１４は本実施の形態２に係る誘導加熱調理器の外加熱コイル負荷抵抗値／内加熱コイル負荷抵抗値と外加熱コイル電力配分係数との関係を示す図である。 Embodiment 2. FIG.
In the second embodiment, a description will be given of a configuration in which a plurality of outer heating coils are arranged so as to surround and surround the outer periphery of the inner heating coil.
FIG. 10 is a diagram illustrating a configuration of a heating coil of the induction heating cooker according to the second embodiment, and FIG. 11 is a diagram illustrating a circuit configuration example of the induction heating cooker according to the second embodiment. 12 is a diagram showing a positional relationship between the heating coil of the induction heating cooker according to the second embodiment and the pan bottom for each pan size, and FIG. 13 shows the internal heating of the induction heating cooker according to the second embodiment. FIG. 14 is a diagram showing the relationship between the coil load resistance value, the external heating coil load resistance value, and the pan size placed above the heating coil, and FIG. 14 shows the external heating coil load of the induction heating cooker according to the second embodiment. It is a figure which shows the relationship between resistance value / inner heating coil load resistance value, and an outer heating coil electric power distribution coefficient.
　実施の形態２に係る図において、実施の形態１に係る図と同一または対応する部分については同一符号を付す。図１０において、複数の加熱コイル１５ａ、１５ｂ１～１５ｂ４は、実施の形態１と同様に、被加熱物である調理容器（鍋など）を載置する天板２２の下方に配設される。内加熱コイル１５ａは被加熱物である鍋底の中心部を加熱する内加熱コイルである。４個の外加熱コイル１５ｂ１～１５ｂ４は、内加熱コイル１５ａの外周の外側で、内加熱コイル１５ａを取り囲むように配置された複数の外加熱コイルである。図１１に示すように、内加熱コイル１５ａはインバーター回路８ａに接続される。外加熱コイル１５ｂ１～１５ｂ４は、インバーター回路８ｂの出力点に並列に接続されている。２４ａ、２４ｂはインバーター回路８ａ，８ｂから出力され、負荷回路１４ａ、１４ｂに印加される高周波電圧を検出する出力電圧検出手段であり、２５ａ、２５ｂは出力電圧検出手段２４ａ、２４ｂと出力電流検出手段１８ａ、１８ｂの出力からインバーター回路８ａ、８ｂの出力電力値を積算して生成する出力電力検出手段である。 In the diagram according to the second embodiment, the same or corresponding parts as those in the diagram according to the first embodiment are denoted by the same reference numerals. In FIG. 10, a plurality of heating coils 15a, 15b1 to 15b4 are arranged below the top plate 22 on which a cooking container (such as a pan) to be heated is placed, as in the first embodiment. The inner heating coil 15a is an inner heating coil that heats the center of the pan bottom, which is an object to be heated. The four external heating coils 15b1 to 15b4 are a plurality of external heating coils arranged outside the outer periphery of the internal heating coil 15a so as to surround the internal heating coil 15a. As shown in FIG. 11, the inner heating coil 15a is connected to the inverter circuit 8a. The outer heating coils 15b1 to 15b4 are connected in parallel to the output point of the inverter circuit 8b. Reference numerals 24a and 24b denote output voltage detection means for detecting a high-frequency voltage output from the inverter circuits 8a and 8b and applied to the load circuits 14a and 14b. Reference numerals 25a and 25b denote output voltage detection means 24a and 24b and output current detection means. This is output power detection means that integrates and generates the output power values of the inverter circuits 8a and 8b from the outputs of 18a and 18b.
　本実施の形態においても、インバーター回路８ａを駆動して負荷回路１４ａに高周波電圧を印加し、出力電流検出手段１８ａで検出した出力電流と、出力電力検出手段２５ａで検出した出力電力値から求まる内加熱コイル抵抗値Ｒｉｎにより、内加熱コイル１５ａの上方に加熱に適した鍋が載置されているか否かを判別することが可能である。本実施の形態２においても、実施の形態１と同様に適正鍋が載置されている場合と、加熱を行わないフォーク等の小物が載置されている場合を判別できるように内加熱コイル抵抗値の閾値Ｒ０を設定する。閾値Ｒ０は加熱コイルの銅線の巻き数等により異なるが、例えば、数Ω程度（２Ω～５Ω）に設定する。 Also in the present embodiment, the inverter circuit 8a is driven to apply a high frequency voltage to the load circuit 14a, and the output current detected by the output current detection means 18a and the output power value detected by the output power detection means 25a are obtained. Based on the heating coil resistance value Rin, it is possible to determine whether or not a pan suitable for heating is placed above the inner heating coil 15a. In the second embodiment, as in the first embodiment, the internal heating coil resistance can be discriminated between the case where the proper pan is placed and the case where a small object such as a fork that is not heated is placed. A value threshold R0 is set. The threshold value R0 varies depending on the number of turns of the copper wire of the heating coil, but is set to, for example, about several Ω (2Ω to 5Ω).
　また、図１２（ａ）に示すような内加熱コイル１５ａの上方のみに鍋底があり、４個の外加熱コイル１５ｂ１～１５ｂ４の上方には鍋底が位置しない小径鍋２３１が載置されている場合、図１２（ｂ）に示すような内加熱コイル１５ａの上方、および４個の外加熱コイル１５ｂ１～１５ｂ４の上方の一部が鍋底で覆われる中径鍋２３２が載置されている場合、図１２（ｃ）に示すような内加熱コイル１５ａおよび４個の外加熱コイル１５ｂ１～１５ｂ４の上方が鍋底で覆われる大径鍋２３３が載置されている場合は、インバーター回路８ａを駆動して出力電流検出手段１８ａと出力電力検出手段２５ａにより検出される内加熱コイル１５ａの出力電流値Ｉ１と出力電力値Ｗ１から算出される内加熱コイル負荷抵抗値Ｒｉｎ（＝Ｗ１／Ｉ１２）と、インバーター回路８ｂを駆動して出力電流検出手段１８ｂと出力電力検出手段２５ｂにより検出される外加熱コイル１５ｂ１～１５ｂ４の出力電流値Ｉ２と出力電力値Ｗ２から算出される外加熱コイル負荷抵抗値Ｒｏｕｔ（＝Ｗ２／Ｉ２２）の比（Ｒｏｕｔ／Ｒｉｎ）から、図１３の関係に基づき判定する。 Also, as shown in FIG. 12 (a), there is a pan bottom only above the inner heating coil 15a, and a small-diameter pan 231 is placed above the four outer heating coils 15b1 to 15b4. FIG. 12B shows a case where a medium-sized pan 232 is placed on the inner heating coil 15a and a part of the four outer heating coils 15b1 to 15b4 are covered with a pan bottom, as shown in FIG. When the large-diameter pan 233 covered with the pan bottom is placed on the inner heating coil 15a and the four outer heating coils 15b1 to 15b4 as shown in FIG. 12 (c), the inverter circuit 8a is driven and output. The inner heating coil load resistance value Rin (= W1 / I12) calculated from the output current value I1 and the output power value W1 of the inner heating coil 15a detected by the current detection means 18a and the output power detection means 25a. And the external heating coil load resistance value calculated from the output current value I2 and the output power value W2 of the external heating coils 15b1 to 15b4 detected by the output current detection means 18b and the output power detection means 25b by driving the inverter circuit 8b. Based on the ratio of Rout (= W2 / I22) (Rout / Rin), the determination is made based on the relationship of FIG.
　本実施の形態２では、Ｒｏｕｔ／Ｒｉｎで鍋径を判別しているので、鍋材質によらず鍋径を判別できる。なお、Ｒｏｕｔ／Ｒｉｎの第１の閾値ｒ１は、外加熱コイル１５ｂ１～１５ｂ４の上方に鍋底が全く位置しない小径鍋２３１（図１２（ａ））が載置された場合と、外加熱コイル１５ｂ１～１５ｂ４の上方の一部に鍋底が位置する中径鍋２３２（図１２（ｂ））が載置された場合を判別できるように設定し、第２の閾値ｒ２は中径鍋２３２が載置された場合と、外加熱コイル１５ｂ１～１５ｂ４の上方全面を覆う大径鍋２３３（図１２（ｃ））が載置された場合とを判別できるように設定する。閾値ｒ１およびｒ２は、例えばｒ１＝０．１～０．２、ｒ２＝１のように設定する。 In this Embodiment 2, since the pan diameter is discriminated by Rout / Rin, the pan diameter can be discriminated regardless of the pan material. The first threshold value r1 of Rout / Rin is the same as when the small-diameter pan 231 (FIG. 12 (a)) where the pan bottom is not positioned at all above the outer heating coils 15b1 to 15b4 and when the outer heating coils 15b1 to 15b4 It sets so that the case where the medium diameter pan 232 (FIG.12 (b)) in which a pan bottom is located in a part above 15b4 is mounted can be discriminate | determined, and the 2nd threshold value r2 has the medium diameter pan 232 mounted. And the case where the large-diameter pan 233 (FIG. 12C) covering the entire upper surface of the outer heating coils 15b1 to 15b4 is placed. The threshold values r1 and r2 are set so that, for example, r1 = 0.1 to 0.2 and r2 = 1.
　そして、図１４に示すように、
（外加熱コイル負荷抵抗値／内加熱コイル負荷抵抗値）＜ｒ１
となる小径鍋２３１の場合には、外加熱コイル目標電力（Ｗｏｕｔ）＝０として、インバーター回路８ａのみを駆動して内加熱コイル１５ａにのみ高周波電流を流すこととし、　ｒ１≦（内加熱コイル負荷抵抗値／外加熱コイル負荷抵抗値）＜ｒ２
となる中径鍋２３２の場合には、内加熱コイル目標電力（Ｗｉｎ）と外加熱コイル目標電力（Ｗｏｕｔ）を、
　Ｗｉｎ＝Ｗａｌｌ×Ｒｉｎ／（Ｒｉｎ＋Ｒｏｕｔ×Ｂ１）
　Ｗｏｕｔ＝Ｗａｌｌ×Ｂ１×Ｒｏｕｔ／（Ｒｉｎ＋Ｒｏｕｔ×Ｂ１）
とし、
　ｒ２≦（内加熱コイル負荷抵抗値／外加熱コイル負荷抵抗値）
となる大径鍋２３３の場合には、内加熱コイル目標電力（Ｗｉｎ）と外加熱コイル目標電力（Ｗｏｕｔ）を、
　Ｗｉｎ＝Ｗａｌｌ×Ｒｉｎ／（Ｒｉｎ＋Ｒｏｕｔ×Ｂ２）
　Ｗｏｕｔ＝Ｗａｌｌ×Ｂ２×Ｒｏｕｔ／（Ｒｉｎ＋Ｒｏｕｔ×Ｂ２）
として（但し、０＜Ｂ１＜Ｂ２）、実施の形態１の図５と同様に加熱制御処理を行うものとする。このように内加熱コイル目標電力と外加熱コイル目標電力を設定して加熱制御処理を行うことにより内加熱コイル負荷抵抗値に対する外加熱コイル負荷抵抗値が所定値以上（大径鍋）である場合に所定値未満（中径鍋）である場合と比較して、内加熱コイルの加熱密度に対する外加熱コイルの加熱密度の比を大きくするように（内加熱コイルに通電する電流量に対する外加熱コイルに通電する電流量を大きくするように）インバーター回路８ａ、８ｂを制御することとなる。 And as shown in FIG.
(External heating coil load resistance value / internal heating coil load resistance value) <r1
In the case of the small-diameter pan 231, the outer heating coil target power (Wout) = 0, only the inverter circuit 8a is driven, and a high-frequency current is allowed to flow only to the inner heating coil 15a, and r1 ≦ (inner heating coil load) Resistance value / outer heating coil load resistance value) <r2
In the case of the medium-diameter pan 232, the inner heating coil target power (Win) and the outer heating coil target power (Wout)
Win = Wall × Rin / (Rin + Rout × B1)
Wout = Wall × B1 × Rout / (Rin + Rout × B1)
age,
r2 ≦ (inner heating coil load resistance value / outer heating coil load resistance value)
In the case of the large-diameter pan 233, the inner heating coil target power (Win) and the outer heating coil target power (Wout)
Win = Wall × Rin / (Rin + Rout × B2)
Wout = Wall × B2 × Rout / (Rin + Rout × B2)
(Where 0 <B1 <B2), the heating control process is performed in the same manner as in FIG. 5 of the first embodiment. When the internal heating coil target power and the external heating coil target power are set in this way and the heating control process is performed, the external heating coil load resistance value with respect to the internal heating coil load resistance value is equal to or greater than a predetermined value (large-diameter pan). The ratio of the heating density of the outer heating coil to the heating density of the inner heating coil is increased as compared with the case where the inner heating coil is less than the predetermined value (medium diameter pan) (the outer heating coil with respect to the amount of current flowing through the inner heating coil) The inverter circuits 8a and 8b are controlled so as to increase the amount of current that is supplied to the inverter.
　上記のように内加熱コイル目標電力、外加熱コイル目標電力を設定してインバーター回路８ａ、８ｂを制御すれば、加熱に適した鍋が載置されている場合には、内加熱コイル負荷抵抗値に対する外加熱コイル負荷抵抗値の比が、所定値ｒ１未満の場合には内加熱コイル１５ａのみに高周波電流を通電する。比（Ｒｏｕｔ／Ｒｉｎ）がｒ１以上ｒ２未満の場合には、外加熱コイル１５ｂ１～１５ｂ４に内加熱コイル１５ａのＢ１倍の高周波電流を通電するように制御する。比（Ｒｏｕｔ／Ｒｉｎ）がｒ２以上の場合には、外加熱コイル１５ｂ１～１５ｂ４に内加熱コイル１５ａのＢ２倍（０＜Ｂ１＜Ｂ２）の高周波電流を通電するように制御する。したがって、加熱に適した材質であれば、その鍋の材質によらず鍋サイズに応じて外加熱コイルと内加熱コイルの高周波電流の大きさの比を調整することができ、大径鍋で鍋底外周部に外加熱コイルによりあまり加熱されない部分が増えた場合には外加熱コイルの加熱密度を増加させ、大径鍋において鍋材質によらず鍋底中心部と鍋底外周部の温度差を抑制した誘導加熱調理器を得ることができる。 If the internal heating coil target power and the external heating coil target power are set as described above and the inverter circuits 8a and 8b are controlled, when a pan suitable for heating is placed, the internal heating coil load resistance value When the ratio of the load resistance value of the outer heating coil with respect to is less than the predetermined value r1, a high-frequency current is applied only to the inner heating coil 15a. When the ratio (Rout / Rin) is greater than or equal to r1 and less than r2, control is performed such that a high frequency current B1 times that of the inner heating coil 15a is supplied to the outer heating coils 15b1 to 15b4. When the ratio (Rout / Rin) is equal to or greater than r2, the outer heating coils 15b1 to 15b4 are controlled to pass a high frequency current B2 times (0 <B1 <B2) that of the inner heating coil 15a. Therefore, if the material is suitable for heating, the ratio of the magnitude of the high frequency current of the outer heating coil and the inner heating coil can be adjusted according to the pan size regardless of the material of the pan. Induction that increases the heating density of the external heating coil when there are more parts that are not heated by the external heating coil on the outer periphery, and suppresses the temperature difference between the center of the pan bottom and the outer periphery of the pan bottom regardless of the pan material A cooking device can be obtained.
　なお、上記実施の形態２の図１１の回路構成図においては、複数の外加熱コイル１５ｂ１～１５ｂ４を並列に接続した例を示したが、図１５に示すように個別のインバーター回路８ｂ１～８ｂ４によって駆動される構成でもよく、また、図１６に示すように直列に接続されている構成であってもよい。 In the circuit configuration diagram of FIG. 11 of the second embodiment, an example in which a plurality of external heating coils 15b1 to 15b4 are connected in parallel is shown. However, as shown in FIG. 15, individual inverter circuits 8b1 to 8b4 are used. The structure driven may be sufficient and the structure connected in series may be sufficient as shown in FIG.
　以上のように本実施の形態２においては、内加熱コイル１５ａの周囲に複数の外加熱コイル１５ｂ１～１５ｂ４を隣接して配設し、内加熱コイル負荷抵抗値Ｒｉｎにより適正（加熱に適した）鍋の有無を判別するとともに、内加熱コイル負荷抵抗値Ｒｉｎと外加熱コイル負荷抵抗値Ｒｏｕｔの比（Ｒｏｕｔ／Ｒｉｎ）により鍋材質によらず鍋サイズを判別し、外加熱コイル外径より大きい所定径以上の大径鍋に対して、内加熱コイル電流（内加熱コイル用インバーター回路出力電流）に対する外加熱コイル電流（外加熱コイル用インバーター回路出力電流）の比を大きくした。すなわち、内加熱コイルの加熱密度に対する外加熱コイルの加熱密度の比を大きくしたので、鍋底中心部と鍋底外周部の温度差を抑制し、鍋底中心部の焦げ付きや鍋底外周部の生焼けが生じ難い誘導加熱調理器を得ることができる。 As described above, in the second embodiment, a plurality of outer heating coils 15b1 to 15b4 are arranged adjacent to the periphery of the inner heating coil 15a, and are appropriate (suitable for heating) by the inner heating coil load resistance value Rin. The presence / absence of the pan is determined, and the pan size is determined regardless of the pan material based on the ratio (Rout / Rin) of the inner heating coil load resistance value Rin and the outer heating coil load resistance value Rout, which is larger than the outer heating coil outer diameter. The ratio of the external heating coil current (inverter circuit output current for the internal heating coil) to the internal heating coil current (inverter circuit output current for the internal heating coil) was increased for large-diameter pans larger than the diameter. That is, since the ratio of the heating density of the outer heating coil to the heating density of the inner heating coil is increased, the temperature difference between the center of the pan bottom and the outer periphery of the pan bottom is suppressed, and the burning of the center of the pan bottom and the outer periphery of the pan bottom hardly occurs. An induction heating cooker can be obtained.
　１　交流電源、２ａ、２ｂ、２ｂ１～２ｂ４　直流電源回路、
３ａ、３ｂ、３ｂ１～３ｂ４　整流ダイオードブリッジ、
４ａ、４ｂ、４ｂ１～４ｂ４　リアクトル、
５ａ、５ｂ、５ｂ１～５ｂ４　平滑コンデンサ、
６ａ、６ｂ、６ｂ１～６ｂ４　入力電流検出手段、
７ａ、７ｂ、７ｂ１～７ｂ４　入力電圧検出手段、
８ａ、８ｂ、８ｂ１～８ｂ４　インバーター回路、
９ａ、９ｂ、９ｂ１～９ｂ４　上スイッチ、
１０ａ、１０ｂ、１０ｂ１～１０ｂ４　下スイッチ、
１１ａ、１１ｂ、１１ｂ１～１１ｂ４　上ダイオード、
１２ａ、１２ｂ、１１ｂ１～１１ｂ４　下ダイオード、
１３ａ、１３ｂ、１３ｂ１～１３ｂ４　駆動回路、
１４ａ、１４ｂ、１４ｂ１～１４ｂ４　負荷回路、
１５ａ　内加熱コイル、１５ｂ、１５ｂ１～１５ｂ４　外加熱コイル、
１６ａ、１６ｂ、１６ｂ１～１６ｂ４　共振コンデンサ、
１７ａ、１７ｂ、１７ｂ１～１７ｂ４　クランプダイオード、
１８ａ、１８ｂ、１８ｂ１～１８ｂ４　出力電流検出手段、
１９　制御手段、２０　操作部、
２１１、２１２、２１３　負荷抵抗検出手段、２２　天板、
２３　鍋、２３１　小径鍋、２３２　中径鍋、２３３　大径鍋、
２４ａ、２４ｂ　出力電圧検出手段、２５ａ、２５ｂ　出力電力検出手段。 1 AC power supply, 2a, 2b, 2b1 to 2b4 DC power supply circuit,
3a, 3b, 3b1-3b4 rectifier diode bridge,
4a, 4b, 4b1-4b4 reactors,
5a, 5b, 5b1 to 5b4 smoothing capacitors,
6a, 6b, 6b1 to 6b4 input current detection means,
7a, 7b, 7b1-7b4 input voltage detection means,
8a, 8b, 8b1 to 8b4 inverter circuit,
9a, 9b, 9b1-9b4 upper switch,
10a, 10b, 10b1 to 10b4 Lower switch,
11a, 11b, 11b1 to 11b4 upper diode,
12a, 12b, 11b1 to 11b4 lower diode,
13a, 13b, 13b1 to 13b4 drive circuit,
14a, 14b, 14b1 to 14b4 load circuit,
15a inner heating coil, 15b, 15b1 to 15b4 outer heating coil,
16a, 16b, 16b1 to 16b4 resonant capacitors,
17a, 17b, 17b1 to 17b4 Clamp diode,
18a, 18b, 18b1 to 18b4 output current detection means,
19 control means, 20 operation unit,
211, 212, 213 Load resistance detection means, 22 Top plate,
23 pans, 231 small pans, 232 medium pans, 233 large pans,
24a, 24b Output voltage detection means, 25a, 25b Output power detection means.

Claims (2)

  1. 　被加熱物である調理容器を載置する天板と、
    　前記天板の下方に配設される内加熱コイルと、
    　前記内加熱コイルの外周の外側に配設される外加熱コイルと、
    　前記内加熱コイルと前記外加熱コイルに高周波電力を供給するインバーター回路と、
    　前記インバーター回路への入力電力あるいは前記インバーター回路からの出力電力を検出する電力検出手段と、
    　前記内加熱コイルと前記外加熱コイルに流れる電流の大きさを検出する出力電流検出手段と、
    　前記電力検出手段および前記出力電流検出手段の検出値に基づき前記インバーター回路を駆動制御する制御手段と、
    　前記内加熱コイルおよび前記外加熱コイルの負荷抵抗をそれぞれ検出する負荷抵抗検出手段と、を備え、
    　前記制御手段が、前記負荷抵抗検出手段により検出した前記外加熱コイルの負荷抵抗が所定値以上の場合に、前記外加熱コイルの負荷抵抗が所定値未満と判断した場合と比較して、前記内加熱コイルに流れる電流値に対する前記外加熱コイルに流れる電流値の比を大きくするように前記インバーター回路を制御することを特徴とする誘導加熱調理器。     A top plate on which a cooking container that is to be heated is placed;
    An internal heating coil disposed below the top plate;
    An outer heating coil disposed outside the outer periphery of the inner heating coil;
    An inverter circuit for supplying high-frequency power to the inner heating coil and the outer heating coil;
    Power detection means for detecting input power to the inverter circuit or output power from the inverter circuit;
    Output current detection means for detecting the magnitude of the current flowing through the inner heating coil and the outer heating coil;
    Control means for driving and controlling the inverter circuit based on detection values of the power detection means and the output current detection means;
    Load resistance detection means for detecting load resistance of the inner heating coil and the outer heating coil, respectively,
    When the control means determines that the load resistance of the external heating coil is less than a predetermined value when the load resistance of the external heating coil detected by the load resistance detection means is greater than or equal to a predetermined value, An induction heating cooker characterized by controlling the inverter circuit so as to increase a ratio of a current value flowing through the outer heating coil to a current value flowing through the heating coil.
  2. 　被加熱物である調理容器を載置する天板と、
    　前記天板の下方に配設される内加熱コイルと、
    　前記内加熱コイルの外周の外側に配設される外加熱コイルと、
    　前記内加熱コイルと前記外加熱コイルに高周波電力を供給するインバーター回路と、
    　前記インバーター回路への入力電力あるいは前記インバーター回路からの出力電力を検出する電力検出手段と、
    　前記内加熱コイルと前記外加熱コイルに流れる電流の大きさを検出する出力電流検出手段と、
    　前記電力検出手段および前記出力電流検出手段の検出値に基づき前記インバーター回路を駆動制御する制御手段と、
    　前記内加熱コイルおよび前記外加熱コイルの負荷抵抗をそれぞれ検出する負荷抵抗検出手段と、を備え、
    　前記制御手段が、前記負荷抵抗検出手段により検出した前記内加熱コイルの負荷抵抗に対する前記外加熱コイルの負荷抵抗の比が所定値以上の場合に、前記内加熱コイルの負荷抵抗に対する前記外加熱コイルの負荷抵抗の比が所定値未満と判断した場合と比較して、前記内加熱コイルに流れる電流値に対する前記外加熱コイルに流れる電流値の比を大きくするようにインバーター回路を制御することを特徴とする誘導加熱調理器。     A top plate on which a cooking container that is to be heated is placed;
    An internal heating coil disposed below the top plate;
    An outer heating coil disposed outside the outer periphery of the inner heating coil;
    An inverter circuit for supplying high-frequency power to the inner heating coil and the outer heating coil;
    Power detection means for detecting input power to the inverter circuit or output power from the inverter circuit;
    Output current detection means for detecting the magnitude of the current flowing through the inner heating coil and the outer heating coil;
    Control means for driving and controlling the inverter circuit based on detection values of the power detection means and the output current detection means;
    Load resistance detection means for detecting load resistance of the inner heating coil and the outer heating coil, respectively,
    When the ratio of the load resistance of the external heating coil to the load resistance of the internal heating coil detected by the load resistance detection means is greater than or equal to a predetermined value, the control means is configured to output the external heating coil to the load resistance of the internal heating coil. The inverter circuit is controlled so as to increase the ratio of the current value flowing through the outer heating coil to the current value flowing through the inner heating coil as compared with a case where the ratio of the load resistance is determined to be less than a predetermined value. Induction heating cooker.
PCT/JP2012/002446 2011-09-20 2012-04-06 Induction heating cooker WO2013042287A1 (en)

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CN104754789A (en) * 2013-12-25 2015-07-01 美的集团股份有限公司 Electromagnetic heating device capable of intelligently identifying the size of pot and control method thereof
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