JP2011249189A - Electromagnetic cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide technique for determining the size of a pan before oil in the pan placed on an electromagnetic cooker is heated up to predetermined heat-retaining temperature so that even when the pan which is different in size is used, control for keeping the oil at the predetermined heat-retaining temperature can be performed, since when the pan placed on the electromagnetic cooker begins to be heated by an excitation coil, the temperature that a temperature detection sensor detects is different if the pan is different in size even if the material of the pan is the same (for example, iron) and the temperature of the oil put in the pan deviates from the predetermined heat-retaining temperature (for example, 180°C), so suitable heating control for keeping the oil at the predetermined heat-retaining temperature needs to be performed in accordance with the size of the pan placed on the electromagnetic cooker.SOLUTION: Temperature detection sensors are arranged at different positions in a radial direction of the excitation coil so as to determine the size of the pan, and the size of the pan is determined from differences in detected temperature among the temperature detection sensors.

Description

  The present invention relates to an electromagnetic cooker in which a cooking utensil generates heat by an electromagnetic induction effect generated by an electric current flowing in an exciting coil, and oil in the cooking utensil can be heated to make a fried food or the like.

  The electromagnetic cooker includes an exciting coil wound in a flat shape so as to correspond to the bottom surface of the cooking vessel (also referred to as pan) on the lower side of the top plate of the electromagnetic cooking device on which the cooking vessel (also referred to as pan) is placed. There is an electromagnetic cooker in which cooking utensils generate heat due to electromagnetic induction caused by the current flowing in the exciting coil, and the oil in the cooking utensils can be heated to make fried foods (see Patent Document 1). In this case, when using an electromagnetic cooker, a cooking container (also referred to as a pan) that generates heat satisfactorily by electromagnetic induction is required, so that a recommended pan is usually specified for each electromagnetic cooker. In particular, when fried (general name including both tempura and fried foods), if the temperature of the oil in the pan is not properly controlled, the quality of the fried food will be reduced. The recommended pan is one in which the size and material of the pan (this is referred to as the type of pan) is specified, and a steel pan of a predetermined size is usually used.

  If this recommended pan is made of iron, but other pans, such as stainless steel pans, are used, the desired fried food cannot be achieved, so the pan material on the induction cooker Technology to determine whether or not the material is made of iron, and if it is made of iron, it shifts to the desired heating state, but if it is not made of iron, it is determined that it cannot be used and does not shift to the heated state There is.

JP 2003-86343 A

  As described above, the electromagnetic cooker has a mechanism in which a pan placed on the electromagnetic cooker generates heat by an electromagnetic induction action, and thus the types of pans to be used are limited. And in an electromagnetic cooker, the system which detects the temperature of oil indirectly is employ | adopted as control for maintaining the temperature of the oil in a pan at predetermined temperature (it is said to maintain this at heat retention temperature). For this reason, it is the structure which detects the temperature of the pan which rose by heating with the temperature detection sensor arrange | positioned under the top plate of the electromagnetic cooker which mounts a pan. When a predetermined iron pan is used, a reference value is set as to what temperature the temperature detection sensor detects, and the temperature of the oil in the pan becomes a predetermined heat retention temperature. The technology that controls the temperature of the oil in the pan to the predetermined heat-retaining temperature while comparing the reference value with the temperature detected by the temperature detection sensor from time to time after energization is started. is there.

  In this way, the electromagnetic cooker is a mechanism that heats the pot placed on it by electromagnetic induction, so the types of pots used are limited and suitable for frying (general name including both tempura and fried food). It is not easy to use when only one specific type of pan is available.

  In view of this point, an object of the present invention is to improve the usability by allowing a plurality of types of pans suitable for fried foods to be used. In that case, it is of course possible to use an iron pan that is generally suitable for frying, but in addition to this, it is also possible to use a stainless steel pan generally sold in stores to improve the usability of the electromagnetic cooker. It is intended.

  When a pan is placed on an electromagnetic cooker and heating is started by an excitation coil with a predetermined input, the size of the pan (substantially the area of the pan bottom corresponding to the excitation coil is affected) even if the same iron pan is used. If they are different, the temperature detected by the temperature detection sensor is different.

  This is because the temperature of the pan generated by heating differs depending on the size of the pan, and the temperature detected by the temperature detection sensor differs. In the control based on the detection of the temperature detection sensor, the temperature of the oil placed in the pan is predetermined. It will deviate from the heat retention temperature (for example, 180 ° C.). For this reason, it is necessary to carry out appropriate heating control for maintaining the oil at a predetermined heat retaining temperature depending on the size of the pan placed on the electromagnetic cooking device.

  In view of this point, the present invention is designed so that the control of maintaining the oil at a predetermined heat-retaining temperature is possible even when different-sized pans are used. This technique provides a technique for determining the size of a pan before the oil is heated to a predetermined temperature.

  The present invention provides a technique for determining the size of a pan by arranging temperature detection sensors at different positions in the radial direction of the exciting coil and determining the size of the pan based on the difference in the detected temperature of the temperature detection sensor. To do.

In the first invention, a switching element is provided so as to control energization to an exciting coil disposed under the top plate of the main body of the electromagnetic cooker, and a drive circuit for driving the switching element and a control signal given to the drive circuit A control unit that controls high-frequency power supplied to the exciting coil to be close to a target power value, and configured to maintain oil in a cooking vessel (or pan) placed on the top plate at a predetermined temperature. In an electromagnetic cooker
A size determination unit is provided that determines the size of the cooking container (or pan) based on a difference in temperature detected by temperature detection sensors arranged at different positions in the radial direction of the excitation coil.

  According to a second invention, in the first invention, the temperature detection sensor includes: a first temperature detection sensor disposed at a central portion of the excitation coil; and a second temperature detection sensor disposed at an intermediate portion in a radial direction of the excitation coil. The size determination means determines the size of the cooking container (or pan) based on a difference in temperature detected by the first and second temperature detection sensors.

  According to the present invention, oil is determined in a predetermined manner by a control operation corresponding to the type of the determined pan by determining the size of the pan based on the difference in temperature detected by the temperature detection sensors arranged at different positions in the radial direction of the exciting coil. It is possible to control the temperature so that

  Moreover, since this invention determines the magnitude | size of a cooking container (or pan) from the difference of the detection temperature of a 1st and 2nd temperature detection sensor, it becomes easy to judge the magnitude | size in the case of iron, and it corresponds to the magnitude | size. By controlling the state, the oil can be controlled to have a predetermined temperature.

It is a perspective view which shows the state which integrated the heating cooker which concerns on this invention in the kitchen equipment stand. It is a perspective view which shows the inside which removed the top plate of the heating cooker which concerns on this invention. It is an energization control circuit of the induction heating coil concerning the present invention. It is a flowchart of the kind (material judgment and magnitude | size) judgment control of the cooking container (or pan) which concerns on this invention. It is a related figure of the voltage and frequency in the kind (material determination and magnitude | size) determination control of the cooking container (or pan) which concerns on this invention. It is a numerical relationship figure of the voltage and drive frequency in the kind (material determination and magnitude | size) determination control of the cooking container (or pan) in FIG. It is a figure which shows the drive frequency of the cooking container (or pan) which concerns on this invention, (A) shows the drive frequency at the time of high input (at the time of 1500W input) using an iron pan, (B) shows the low of iron pan use The drive frequency at the time of input (at the time of 500W input) is shown. It is a figure which shows the state in which the drive frequency in the case of increasing the input of the cooking container (or pan) which concerns on this invention is reduced gradually. It is a figure which shows the change of the detected temperature of the temperature of the oil, pan bottom TH, and coil TH in case the cooking container (or pan) which concerns on this invention is a large diameter iron pan. It is a figure which shows the change of the detection temperature of the temperature of the oil in case the cooking container (or pan) which concerns on this invention is a small diameter iron pan, pan bottom TH, and coil TH. It is a flowchart which concerns on other embodiment of the material determination control of the cooking container (or pan) which concerns on this invention.

In the present invention, a switching element is provided to control energization to an exciting coil disposed under the top plate of the electromagnetic cooker body, and the driving circuit for driving the switching element and the control signal given to the driving circuit A control unit that controls the high-frequency power supplied to the exciting coil to be close to the target power value is configured to maintain the oil in the cooking container (or pan) placed on the top plate at a predetermined temperature. In an electromagnetic cooker,
The present invention includes a size determination means for determining the size of the cooking container (or pan) based on a difference in temperature detected by temperature detection sensors arranged at different positions in the radial direction of the excitation coil. The example of the electromagnetic cooker which concerns is described based on a figure.

  Hereinafter, as an example of the present invention, an embodiment of an electromagnetic cooker 1 having one induction heating coil 4 and one radiant heater 5 will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a state in which the electromagnetic cooking device 1 according to the first embodiment of the present invention is attached to a kitchen equipment table 7. The electromagnetic cooker 1 is a form incorporated into the insertion hole of the upper surface plate 7A of the kitchen equipment table 7 such as a system kitchen, a cooking table or a sink, by a drop-in method, and a main body 2 that forms a substantially rectangular case. And a top plate 3 made of heat-resistant glass supported by a top plate frame 6 attached to the upper surface portion of the main body portion 2, and the main body portion 2 has a front and rear space in the lower space corresponding to the top plate 3. An induction heating coil 4 (hereinafter referred to as an excitation coil 4) and a radiant heater 5 are provided as heat sources that are installed at intervals. The main body 2 forms a substantially rectangular case having an upper surface opening by a side wall 2B attached to the bottom wall 2A so as to surround the bottom wall 2A and surrounding four sides. Moreover, the top plate 3 made of heat-resistant glass is in a state where the peripheral portion is supported by a top plate frame 6 attached to the side wall 2B with screws so as to cover the upper surface opening of the main body 2.

  A circular cooking container is placed on the top surface of the top plate 3 corresponding to the excitation coil 4 and the radiant heater 5 in order to clearly show the place where the cooking container 10 such as a pan (hereinafter referred to as the pan 10) is placed. Parts 8 and 9 are displayed by printing or the like. In the embodiment, the exciting coil 4 has a calorific value at a rated voltage of 200 V (volt) and a maximum input (or maximum input) of 1500 W (watt), and the radiant heater 5 has a rated voltage of 200 V and a maximum input (or rating). Input) Although it is a thing of the emitted-heat amount in 1200w, it is not limited to this.

  Below the upper surface plate 7A of the kitchen equipment table 7 (the sink 7) is an article storage space 12A, and the front surface of the article storage space 12A can be opened and closed by an open / close door. As described above, in the electromagnetic cooker 1 dropped into the insertion hole of the kitchen equipment stand 7, the bottom wall 2A of the main body 2 is exposed above the article storage space 12A.

  An excitation coil 4 and a radiant heater 5 are arranged in the main body 2. The excitation coil 4 is attached to the upper surface of a synthetic resin support frame 4A. The support frame 4A is supported by a synthetic resin base member 20 attached to the bottom wall 2A of the main body 2 by a coil spring, and the periphery of the support frame 4A. The flange is biased upward so that the flange contacts the lower surface of the heat-resistant glass top plate 3. As a result, the exciting coil 4 is held in a substantially horizontal state close to the lower surface of the top 3. Further, the radiant heater 5 is mounted in a heat-resistant support frame 5A having an opening on the upper surface, and the support frame 5A is supported by coil springs 19 at a plurality of locations on the upper surface of a support base 18 mounted so as to rise from the bottom wall 2A. The support frame 5A is urged upward so as to contact the lower surface of the top plate 3 made of heat-resistant glass. As a result, the radiant heater 5 is held in a substantially horizontal state in proximity to the lower surface of the top plate 3.

  The electromagnetic cooker 1 includes an operation switch unit 13 for performing energization control and heat generation control of the excitation coil 4 and the radiant heater 5, an LED display unit 14 corresponding to the operation switch unit 13, and the like at the front of the top frame 6. An operation unit 15 is provided. Further, a control device 30 constituting a control circuit unit for performing energization control and heat generation control of the exciting coil 4 and the radiant heater 5 and a heat radiation fin 27 of the control device 30 are mounted inside the main body 2. The printed wiring board 25 is attached to the upper surface of the synthetic resin base member 20. A cooling fan (not shown) for cooling the heat radiation fins 27 and cooling the exciting coil 4 and the radiant heater 5 is provided inside the main body 2, and the exhaust from the cooling fan is connected to the rear side wall. The air passes through the exhaust slit 28 formed in 2B and is discharged upward from the exhaust unit 16 formed in the rear part of the top frame 6. An exhaust cover 17 having a large number of exhaust holes 17A is attached to the exhaust portion 16. A control circuit unit for performing energization control and heat generation control of the exciting coil 4 and the radiant heater 5 and a printed wiring board 25 to which the heat dissipation fins 27 of the control circuit unit are attached are formed on the upper surface of the synthetic resin base member 20. It is attached.

  The excitation coil 4 attached to the upper surface of the support frame 4A is suitable for heating both the small and large ones of the bottom surface of the pan 10 placed on the top plate 3, The inner coil portion 4P and the outer coil portion 4Q that are connected in series are separately arranged concentrically.

  In order to mainly detect the heating state of the pot 10, a temperature detection sensor (hereinafter referred to as the pot bottom) that mainly detects the pot bottom temperature of the pot 10 is provided at the center of the inner coil portion 4 </ b> P so as to be positioned at the center of the exciting coil 4. TH). Further, a temperature detection sensor (hereinafter referred to as a coil TH) that mainly detects the temperature of the exciting coil 4 and the temperature of the bottom periphery of the pan 10 is disposed between the inner coil portion 4P and the outer coil portion 4Q.

  A control device 30 for electrically controlling the electromagnetic cooker 1 is shown in FIG. The control device 30 mainly includes a resonance circuit 32 having an excitation coil 4 and a resonance capacitor 31 connected in parallel thereto, a rectification circuit 34 that converts AC power supplied from a commercial power supply 33 into DC power, and a rectification circuit 34. In order to convert the DC power input from RF into high frequency power and supply it to the exciting coil 4, each of the inverter circuit 36 having switching elements 35A and 35B connected to the resonance circuit 32 and the switching elements 35A and 35B is switched. Drive circuits 37A and 37B for controlling the operation, and a control unit 38 for controlling the high frequency power supplied to the exciting coil 4 to be close to the target power value by changing the drive frequency of the control signal given to the drive circuits 37A and 37B. It has. In the embodiment, the AC power supplied from the commercial power source 33 is AC power having a rated voltage of 200 volts (hereinafter referred to as 200 V). In addition to this, the control device 30 also includes a control circuit unit that controls energization of the radiant heater 5.

  In addition to this, the control device 30 includes analog temperature values and voltage values of the temperature detection circuit 39, the current detection circuit 40, the voltage detection circuit 41, the current detection circuit 40, and the voltage detection circuit 41 based on the temperature detection of the pan bottom TH and the coil TH. Is converted to a digital value. The control unit 38 receives a switch operation signal from the operation unit 15, a signal from the temperature detection circuit 39, a signal from the A / D conversion circuit 42, and the like so as to play a central role in controlling the power of the excitation coil 4. The CPU 43 as a central processing unit, the ROM 44 that is a memory that stores an operation program executed by the CPU 43, the RAM 45 that is a memory that stores information for the CPU 43 to perform a control operation, and the like. The capacitor 31S is a snubber capacitor.

  The high frequency power supplied to the exciting coil 4 is input power calculated from the current value detected by the current detection circuit 40 and the voltage value detected by the voltage detection circuit 41, and this is the output power of the electromagnetic cooker 1. (For example, the maximum output is 1500 W). This input can be controlled by controlling the switching time by ON-OFF of the switching elements 35A and 35B by the drive circuits 37A and 37B.

  When the input time is controlled by controlling the switching time by ON / OFF of the switching elements 35A and 35B by the drive circuits 37A and 37B, the drive time is lowered and the energization time to the exciting coil 4 is as shown in FIG. The input is increased if the length is increased, and the input is decreased if the drive frequency is increased and the energization time to the exciting coil 4 is shortened as shown in FIG. 7B. For this reason, in order to set the high-frequency power supplied to the exciting coil 5 to a high input 1500 W, the switching elements 35A and 35B are controlled to be turned on and off at a low frequency corresponding to that as shown in FIG. do it. Further, in order to set the high frequency power supplied to the exciting coil 5 to a low input of 500 W, the switching elements 35A and 35B are controlled to be turned on and off at a high frequency corresponding to that as shown in FIG. 7B. That's fine.

  A control method for variably controlling the drive frequency so as to achieve a predetermined target power value will be described. FIG. 8 is an explanatory diagram when the drive frequency is gradually lowered when heating to a predetermined target power value. In FIG. 8, if the target power value is 1500 W, for example, when the exciting coil 4 is driven at a certain driving frequency (indicated by (1) KHz), it is checked whether or not the input is 1500 W. If 1500 W is not output, the excitation coil 4 is driven at a predetermined drive frequency (indicated by (2) KHz) lower than that to check whether the input is 1500 W. Here, if 1500 W is not yet output, the exciting coil 4 is driven at a predetermined drive frequency (indicated by (3) KHz) lower than that to check whether the input is 1500 W. In this way, the drive frequency is changed so that the input is 1500 W. It should be noted that Ta1: Tb1 = Ta2: Tb2 = Ta3: Tb3 = 1. In the description of FIG. 8 and FIG. 8, ((1) KHz) and ((2) KHz) do not indicate 1 KHz and 2 KHz. In (1) and (2), some numerical value such as 200 or 100 is entered.

  More specifically, when the deep-fried food cooking is started by operating the deep-fried food switch 13B in the state where the target power value is set to 1500 W in the electromagnetic cooker 1, the controller 38 first heats at 1500 W. Start and divide 1500 W by the voltage value detected by the voltage detection circuit 41 at a predetermined time interval to obtain a current value I1 at that time, and divide this I1 by the set value I0 to obtain a calculated value at that time x1 is calculated, and the exciting coil 4 is driven at a driving frequency f1 corresponding to x1. Similarly, at a predetermined time interval, 1500 W is divided by the voltage value detected by the voltage detection circuit 41 to obtain a current value I2 at that time, and this I2 is divided by the set value I0 to obtain the current value. A calculated value x2 is calculated, and the exciting coil 4 is driven at a drive frequency f2 corresponding to x2. With this relationship, the excitation coil 4 is driven with the drive frequencies f1, f2, f3... Corresponding to the calculated values x1, x2, x3... And controlled until the target power value reaches 1500 W. The In this control, a table indicating the correspondence between the calculated values x1, x2, x3... And the drive frequencies f1, f2, f3... Is set in the ROM 44 or RAM 45.

  For example, in the control for reducing the input to 500 W when heating at 1500 W, similarly to the above, the drive frequencies f1, f2, f3 corresponding to the calculated values x1, x2, x3. Depending on the relationship, the excitation coil 4 is driven while gradually increasing the drive frequency, and it is checked whether or not 500 W has been output. If 500 W has not yet been output, the excitation coil has a higher predetermined drive frequency. 4 is driven, and control is performed until the target power value reaches 500 W by checking whether or not the input is 500 W again.

  As shown in FIG. 8, the ON-OFF timings of the waveforms of the drive frequencies for performing the ON-OFF control of the switching elements 35A and 35B are opposite to each other. Then, in order to prevent a large current from flowing at the time of ON-OFF switching and destroying the switching elements 35A and 35B, an operation with a certain switching time difference as shown in d is performed. .

  The target power value is usually referred to as an input of the electromagnetic cooker 1, and in the embodiment, when the rated voltage of the AC power supplied from the commercial power supply 43 is 200V, the maximum value of the electromagnetic cooker 1 is set. The maximum input, which is the target power value, is 1500 watts (hereinafter referred to as 1500 W).

  When the pan 10 filled with oil is placed in the electromagnetic cooker 1 and heating is started by the excitation coil 4 with a certain input, the temperature detected by the pan bottom TH when the pan 10 is made of iron, and pans of other materials The temperature detected by the pan bottom TH when used is different. Since the temperature rise of the pan 10 varies depending on the heating, the temperature detected by the pan bottom TH varies depending on the material of the pan 10, and the temperature of the oil placed in the pan 10 deviates from a predetermined heat retention temperature. For this reason, it is necessary to carry out appropriate heating control for maintaining the oil at a predetermined heat-retaining temperature depending on what kind of material the pan 10 is made of. In this regard, even when a plurality of types of pans 10 are used, the energization control of the exciting coil 4 is performed so as to determine the material of the pan 10 and to output a predetermined rated input, thereby maintaining the oil at a predetermined temperature. Therefore, a technique for determining the material of the pan 10 placed on the electromagnetic cooker 1 is provided. This technique is described below.

  In the present invention, the operation unit 15 is provided to start heating in a state where a pan 10 containing a predetermined amount of oil (for example, 500 g) is placed on the top surface of the top plate 3 corresponding to the excitation coil 4. The power switch 13A, which is one of the operated switch sections 13, is operated to the ON state. In this state, the deep-fried food switch 13B is operated, the control unit 38 operates based on the ON signal, and the CPU 43 executes the processing operation according to the operation program stored in the ROM 44.

  Thus, the deep-fried food switch 13B is operated and the control part 38 operate | moves based on the ON signal. Thereby, the heating of the pan 10 is started, and the oil therein is heated. The material determination of the pan 10 is performed within a predetermined time (in the embodiment, within 40 seconds) from this start. This material determination will be described based on the flowchart of FIG. The flowchart shown in FIG. 4 shows the steps of the processing operation executed by the CPU 43 in accordance with the operation program stored in the ROM 44. The temperature determination by each temperature determination means, the material determination means for determining the material of the pan 10, Each determination means such as a size determination means for determining the size of the pan 10 means an operation unit executed as a processing operation of the CPU 23 for each step shown in FIGS. 4 and 11.

  Specifically, the power switch 13A is operated to the ON state with the pan 10 in which a predetermined amount (for example, 500 g) of oil is placed on the cooking container mounting portion 8 (step S1 in FIG. 4). ), The control device 30 is in an operable state, and the CPU 43 is in a state in which the processing operation can be executed in accordance with the operation program stored in the ROM 44. Then, when the deep-fried food switch 13B is turned on as a frying start (step S2 in FIG. 4), the CPU 23 executes the processing operation and heats the pan 10 with a constant high input 1500 W (FIG. 4). The process proceeds to step S3).

  Then, by the operation of the control unit 38, the constant input power calculated based on the current value detected by the current detection circuit 40 and the voltage value detected by the voltage detection circuit 41 is supplied to the exciting coil 4 and heating is started. (Step S3 in FIG. 4). In step S3, the inverter circuit 16 is controlled by varying the drive frequency applied to the drive circuits 17A and 17B so that the high-frequency power supplied to the exciting coil 4 becomes an input 1500 W that is a target power value. As described above with reference to FIG. 8, this variable control of the drive frequency drives the exciting coil 4 with the drive frequencies f1, f2, f3... Corresponding to the calculated values x1, x2, x3. Thus, control is performed so as to obtain a predetermined target power value. In this state, if the driving frequency at that time is checked, the material of the pan 10 currently used can be determined.

  The present invention applies this technical idea so that three types of pots 10 can be used. Hereinafter, the determination means will be described.

  In the present invention, it is determined whether or not a first predetermined time (for example, 20 seconds) has elapsed from the start of heating at 1500 W (step S3) in order to stably determine the material of the pan 10 (FIG. 4). Step S4) When 20 seconds have elapsed (YES), the first frequency determination means starts checking (measuring) the drive frequency (Step S5 in FIG. 4). The circuit configuration in which the CPU 43 executes the processing operation is provided with first frequency detection means for detecting the drive frequency of the control signal (PWM signal) to be supplied to the drive circuit 37, whereby the drive frequency is checked.

  Then, it is determined whether or not a second predetermined time (for example, 40 seconds) longer than the first predetermined time has elapsed since the start of heating at 1500 W (step S6 in FIG. 4). The process proceeds to step S7 and subsequent steps in FIG. For this reason, the material of the pot 10 is determined by the material determination means from step S7 to step 11 in FIG. 4 according to the driving frequency checked between the first predetermined time (for example, 20 seconds) and the second predetermined time (for example, 40 seconds). It means to judge.

  As described above, in the present invention, when the drive frequency of the control signal exceeds the predetermined upper limit value A or exceeds the predetermined upper limit value A in step S7 and step S8 of FIG. (In this case, the pan 10 made of SUS18-8) is determined (step S9 in FIG. 4). When the predetermined lower limit B or less or less than the predetermined lower limit B, the second type of pan 10 (here, SUS18). -0 made pan 10) (step S10 in FIG. 4), and if it is within the range between the upper limit value A and the lower limit value B, the third type material pan 10 (here, iron pan 10) It determines (step S11 of FIG. 4) The material determination means is provided. This determination is performed by a material determination unit configured by the control unit 30.

  If the determination by this material determination means is demonstrated in detail, in step S7 and step S8 of FIG. 4, the material of the pot 10 will be determined by whether the drive frequency of the control signal is higher or lower than a predetermined upper limit value A. First determining means (step S7 in FIG. 4), and second determining means (step S8 in FIG. 4) for determining the material of the pan 10 depending on whether it is higher or lower than the predetermined lower limit B.

  More specifically, in step S7 and step S8 in FIG. 4, it is determined whether or not the drive frequency of the control signal is equal to or higher than a predetermined upper limit value A or exceeds a predetermined upper limit value A. First determination means (steps S7 and S9 in FIG. 4) for determining that the pan 10 is a first type of material (here, pan 10 made of SUS18-8) when A exceeds A or a predetermined upper limit A. Second determination means (step S8 in FIG. 4 and step S8 in FIG. 4) that determines that the pan is made of the second type of material (here, the pan 10 made of SUS18-0) when it is less than or equal to the predetermined lower limit B or less than the predetermined lower limit B. S10) and third determination means (step S7 in FIG. 4) for determining that the pot is a third type of pot 10 (here, iron pot 10) if it is within the range between the upper limit value A and the lower limit value B. S8 and S11).

  In an Example, the iron pan 10, the SUS18-0 pan 10, and the SUS18-8 pan 10 are set as the applicable pan 10, In that case, within the range of the upper limit A and the lower limit B If the upper limit value A and the lower limit value B are set so that the iron pan 10 is obtained, the pan 10 made of SUS18-8 is formed in the upper region, and the pan 10 made of SUS18-0 is formed in the lower region. Judgment can be made easily. That is, the SUS18-8 pan 10 has a higher drive frequency than the frequency determination range of the iron pan 10 that is the range between the upper limit A and the lower limit B (described as the frequency iron determination range in FIG. 4). Since the SUS18-0 pan 10 has a lower driving frequency than the iron pan 10, in steps S7 and S8 in FIG. 4, the determination is based on the iron pan 10 or the SUS18-0 pan. It is the structure which determines whether it is the pan 10 or the SUS18-8 pan 10. This is substantially the same as the case where the determination is made by comparing the upper limit value A (reference value upper limit A) and the lower limit value B (reference value lower limit B) as described above.

  As described above, heating is performed at a constant input 1500 W for a second predetermined time (for example, 40 seconds) from the start of heating, and during the first predetermined time (for example, 20 seconds) to the second predetermined time (for example, 40 seconds). The material of the pan 10 is determined by the material determination means from step S7 to step 11 in FIG. Thus, when the oil is started to be heated to a predetermined temperature of 180 ° C., the material judgment of the pan 10 is performed. The oil is not yet heated to the predetermined temperature of 180 ° C. This is because a phenomenon in which the value of the drive frequency for maintaining the temperature varies depending on the material of the pan 10 can be accurately captured.

  5 and 6 show the relationship of the drive frequency to the power supply voltage (voltage rectified by the rectifier circuit 34) detected by the voltage detection circuit 41 for each type of pan 10 when heating is started at 1500W. ing. As shown in FIG. 5, when the reference power supply voltage is 200V, the power supply voltage has two types of iron pans so that regular material determination can be performed even when the power supply voltage fluctuates within a range of ± 20V. 10, the upper limit A and the lower limit B for setting the SUS18-0 pan 10 and the SUS18-8 pan 10 as the applicable pan 10 are set in the ROM 44 or the RAM 45.

  As shown in FIG. 5, when the power supply voltage is 200 V, the upper limit value A of the drive frequency (described as the reference value upper limit A in FIG. 6) in the material determination is 26.3 KHz, and the lower limit value B of the drive frequency. (Described as reference value lower limit B in FIG. 6) is 23.4 KHz. When the power supply voltage is in the range of 180 V to 220 V, the upper limit value A of the drive frequency is the value indicated by the graph G1, and the lower limit value B of the drive frequency is the value indicated by the graph G2. As is apparent from FIG. 5, the range of the graph G1 and the graph G2 is the iron pan 10 which is the third type of pan 10, and the one of the first type of pan which is equal to or higher than the graph G1. It is the pan 10 made from SUS18-8 which is 10, and the thing below the graph G2 or less shows that it is the pan 10 made from SUS18-0 which is the 2nd kind of pan 10.

  For this reason, the graph G3 shown in FIG. 5 is one type of commercially available iron fried pan 10 having a bottom diameter of 10 cm. Moreover, the graph G4 is one of the iron fried pans 10 made of iron prepared exclusively for the electromagnetic cooker 1 of the embodiment, and is the iron fried pan 10 having a bottom diameter of 22 cm. Moreover, the graph G5 shown in FIG. 5 is one of the SUS18-8-made pans 10 with a bottom diameter of 18 cm, and the graph G6 is one of the SUS18-0-made pans 10.

  6, among the graph values shown in FIG. 5, the upper limit value A (reference value upper limit A), the lower limit value B (reference value lower limit B) when the power supply voltage is 180 V, 200 V, and 220 V, G3: commercially available iron The driving frequency of the frying pan 10, G4: the driving frequency of the iron fried pan 10 made of iron, G5: the driving frequency of the pan 10 made of SUS18-8, and G6: the driving frequency of the pan 10 made of SUS18-0 are shown.

  Thus, if the upper limit A and the lower limit B are within this range, the value determined so that many iron pans can be used in consideration of the size and material of the iron pan suitable for normal use. It is. For this reason, the frequency range between the upper limit value A and the lower limit value B can be referred to as an iron determination range as described in step S7 in FIG. It can be said that the SUS18-8 pan 10 is above or beyond this range, and the SUS18-0 pan 10 is below or below this range.

  As described above, after the material determination of the pot 10 is performed by the operations from step S1 to step 11 in FIG. 4, the process proceeds to step S12 in FIG. 4, and the process proceeds to the size determination of the pot 10. Hereinafter, the size determination of the pan 10 will be described.

  In step S12 of FIG. 4 in which the size determination of the pan 10 is started, the drive frequency applied to the drive circuits 17A and 17B is set so that the high frequency power supplied to the exciting coil 4 becomes the input 1100 W which is the target power value. The inverter circuit 16 is controlled by the variable. As described above with reference to FIG. 10, this variable control of the driving frequency drives the exciting coil 4 with the driving frequencies f1, f2, f3... Corresponding to the calculated values x1, x2, x3. Thus, control is performed so as to obtain a predetermined target power value.

  Then, in step S13 of FIG. 4, it is determined by the determination means whether the detected temperature of the pan bottom TH is 120 ° C. or higher. If it is 120 ° C. or higher, the step is performed in step S14 of FIG. Whether or not the material of the pan 10 determined in S7 to Step S11 is the iron pan 10 is determined by the determining means. If the determination is not the iron pan 10, the process proceeds to step S16 in FIG. The case where it is not the iron pan 10 of this determination is the pan 10 made of SUS18-8 and the pan 10 made of SUS18-0 by the said material determination. On the other hand, when the determination in step S14 is the iron pan 10, the process proceeds to step S15 in FIG.

  In the present invention, depending on the detected temperature of the coil TH and the detected temperature of the pan bottom TH, the size of the iron fried pan 10, that is, the pan 10 having a small diameter on the bottom surface or the pan 10 having a large diameter on the bottom surface. In order to determine whether or not there is a configuration, the arrangement of the coil TH is set at a position distant from the pan bottom TH disposed at the center of the exciting coil 4 in the radial direction.

  In step S15 of FIG. 4, the determination means determines whether the bottom diameter of the iron fry pan 10 is large or the bottom diameter of the fried iron pan 10 is small, based on the detection temperature of the coil TH and the detection temperature of the pan bottom TH. Is done. This determination is a determination of the size of the iron pan 10, and the determination criterion is whether or not the diameter of the bottom surface of the iron pan 10 is greater than or equal to a predetermined diameter (in the embodiment, 14 cm as a reference). Here, if the detected temperature of the coil TH is equal to or higher than the detected temperature of the pan bottom TH, it is determined that the bottom diameter of the iron fried pan 10 is small (step S17 in FIG. 4), and the detected temperature of the coil TH is the pan bottom TH. If the temperature is less than or less than the detected temperature, it is determined that the bottom of the iron fried pan 10 has a large diameter (step S18 in FIG. 4).

  Regarding the size determination of such a pan 10, the pan 10 employed in the embodiment will be described below.

  In the embodiment, in order to heat both the small-diameter pan 10 and the large-diameter pan 10 that are normally used by the exciting coil 4, the diameter of the exciting coil 4, that is, the outer diameter of the outer coil portion 4Q. The inner coil portion 4P and the outer coil portion 4Q are formed so as to be approximately 15 cm and suitable for heating both the small-diameter pan 10 and the large-diameter pan 10.

  In the present invention, in the iron fried pan 10, the pan bottom diameter is determined based on a predetermined diameter (in the embodiment, 14 cm is a reference), and the pan having a pan bottom diameter larger than 14 cm is determined as the large-diameter pan 10, A pot whose diameter at the bottom of the pot is smaller than 14 cm is determined to be a large diameter pot 10. This is an example, and the present invention is not bound by this number.

  Since the pan bottom TH is located at the center of the exciting coil 4, the pan bottom temperature of the pan 10 is mainly detected in both the small-diameter pan 10 and the large-diameter pan 10. On the other hand, the portion between the inner coil portion 4P and the outer coil portion 4Q is affected by heating by both the inner coil portion 4P and the outer coil portion 4Q, and this portion has the same temperature in the exciting coil 4 portion. It is a part that tends to be expensive. The coil TH is arranged here, and depending on the temperature state, the size of the pan 10, that is, whether the bottom diameter is a small diameter pan 10 or the bottom diameter is a large diameter pan 10 is determined. Can do.

  The iron pan 10 having a pot bottom diameter of 22 cm is heated by both the inner coil portion 4P and the outer coil portion 4Q in the state where it is placed on the cooking container mounting portion 8 at the regular position, but it has an excitation of approximately 15 cm in diameter. There are many pot bottom parts located in the outer side of the coil 4, and the detection temperature of coil TH becomes low. For this reason, when the detected temperature of the pan bottom TH reaches 120 ° C., that is, when the detected temperature of the pan bottom TH is 120 ° C. or more, or exceeds the detected temperature of the coil TH, as shown in FIG. In this case, the temperature is determined to be the iron fried pan 10 having a large diameter at the bottom (step S18 in FIG. 4).

  On the other hand, the pan 10 having a pan bottom diameter of 10 cm is covered with the coil TH within the range of the exciting coil 4 having a diameter of about 15 cm when placed in the normal position on the cooking vessel mounting portion 8. When there is almost no pan bottom portion located outside of 4 and the entire pan bottom is heated by both the inner coil portion 4P and the outer coil portion 4Q, the detection temperature of the pan bottom TH reaches 120 ° C., that is, detection of the pan bottom TH When the temperature is equal to or higher than 120 ° C., the detected temperature of the coil TH becomes higher than the detected temperature of the pan bottom TH as shown in FIG. For this reason, it is determined that the bottom diameter of the iron fried pan 10 is small (step S17 in FIG. 4).

  In the above description, the size is determined in the iron fried pan 10 as a material suitable for fried food. However, in the case of the stainless steel pan 10 made of SUS18-8 or SUS18-0, the detected temperature of the coil TH and the pan bottom If the reference value can be set so as to determine the size of the pan 10 according to the relationship of the detected temperature of TH, the size determination of the stainless steel pan 10 can be performed.

  FIG. 11 is a flowchart of another material determination control according to the material determination according to the present invention. The determination result is substantially the same as the material determination control performed in the material determination control flowchart shown in FIG. The present invention may be any control flow of FIG. 4 and FIG. Also, other control flows may be used within the technical scope of the present invention. Below, it demonstrates based on the control flow of FIG.

  In FIG. 11, with the pan 10 containing a predetermined amount of oil placed on the cooking container placing portion 8, the power switch 13A is turned on (step S111 in FIG. 11), and the control device 30 is turned on. Becomes an operation state, and the CPU 43 enters a state in which the processing operation is executed according to the operation program stored in the ROM 44. Then, when the deep-fried food switch 13B is turned on (step S221 in FIG. 11) to start frying, heating at 1500 W is started as in FIG. 4 (step S331 in FIG. 11).

  And in order to make it the state which can perform the material determination of the pan 10 stably, it is determined whether the 1st predetermined time (for example, 20 seconds) passed from the heating start at 1500 W (step S441 of FIG. 11), 20 When the second has elapsed (YES), the first frequency determination means starts checking (measuring) the drive frequency (step S551 in FIG. 11). The circuit configuration in which the CPU 43 executes the processing operation is provided with first frequency detection means for detecting the drive frequency of the control signal (PWM signal) to be supplied to the drive circuit 37, whereby the drive frequency is checked.

  Then, it is determined whether or not a second predetermined time (for example, 40 seconds) longer than the first predetermined time has elapsed from the start of heating at 1500 W (step S661 in FIG. 11), and when 40 seconds have elapsed (YES), the material determining means Thus, the process proceeds to step S77 and subsequent steps in FIG. The provision of the first predetermined time (for example, 20 seconds) and the second predetermined time (for example, 40 seconds) is driven between the first predetermined time (for example, 20 seconds) and the second predetermined time (for example, 40 seconds). The frequency is checked, and the material of the pan 10 is determined by comparing the drive frequency with a reference value. The oil has not yet been heated to a predetermined temperature of 180 ° C., and at the beginning of heating the oil By determining the material of the pot 10, the heating is controlled in a state commensurate with the material of the pot 10.

  In step S771 and step S881 of FIG. 11, when the drive frequency of the control signal exceeds a predetermined upper limit value A or exceeds a predetermined upper limit value A, the pan 10 of the first type material (here, made of SUS18-8). Pan 10) (step S991 in FIG. 11), when the predetermined lower limit B or less or less than the predetermined lower limit B, the second type of pot 10 (here, the pan 10 made of SUS18-0) If it determines (step S1010 of FIG. 11) and it exists in the range of the said upper limit A and the said lower limit B, it will determine with the pan 10 (here iron pan 10) of a 3rd type material (step S1111 of FIG. 11). ) It has a judging means. This determination is performed by the determination unit configured by the control unit 30 and is the same as that described in FIG.

  As described above, after the material determination of the pan 10 is performed by the operations from step S111 to step 1111 in FIG. 11, the process proceeds to step S12 in FIG. 4, and the size determination of the pan 10 is performed as described above. The

  After the material of the pan 10 is determined as described above and the size of the pan 10 is further determined, the control unit 30 is configured to maintain the oil in the pan 10 at a predetermined temperature (for example, 180 ° C.). The heating control operation corresponding to the ten types is performed (step S20 in FIG. 4). Step S19 in FIG. 4 is another processing step (for example, oil amount measurement) executed in the process of moving to step S20 after the above-described material determination and size determination are completed.

  In step S20, after determining the material of the pan 10 as described above, for example, it is determined that the pan 10 is made of iron, and the size is determined to be, for example, a small-diameter iron fried pan 10 of the pan. Accordingly, the temperature of the oil is controlled so as to be a predetermined heat retention temperature of 180 ° C. suitable for fried food (tempura and fried food). Moreover, when it is determined by the material determination of the pan 10 as described above that it is a pan 10 made of, for example, SUS18-8, and in step 14 of the size determination flow, it is also determined that the pan is not an iron fried pan 10. In S20, the temperature of the oil is controlled so as to be a predetermined heat retaining temperature of 180 ° C. suitable for fried food (tempura or fried food) according to the characteristics of the pan 10.

  For this reason, in step S20, the CPU 43 operates via the temperature detection circuit 39 and the A / D conversion circuit 42 by a signal based on the temperature detection of the pan bottom TH, and by changing the drive frequency given to the drive circuits 17A and 17B, The inverter circuit 16 is controlled. The variable control of the driving frequency is performed by a driving circuit based on a driving frequency determined by comparing data based on temperature detection of the pan bottom TH with reference data (table data set in the ROM 44 or RAM 45) determined for each type of the pan 10. 17A and 17B operate, and the inverter circuit 16 is controlled so that the oil temperature is controlled to a predetermined heat retention temperature of 180 ° C.

  In addition, when it transfers to step S20 and the heating control operation | movement according to the kind of pan 10 is performed by the control part 30 so that oil may be maintained to predetermined | prescribed heat retention temperature, the pan 10 heats efficiently by supplying with electricity to the exciting coil 4 In order to achieve the state, the inverter circuit 36 can be driven at a drive frequency set based on the resonance frequency of the resonance circuit 32. Usually, the driving frequency at this time is substantially the same as the resonance frequency or a slightly higher frequency.

  The electromagnetic cooker according to the present invention is not limited to the configuration shown in the above embodiment, but can be applied to various forms, and includes various forms within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Electromagnetic cooker 2 ... Main part 2A ... Bottom wall of main part 3 ... Top plate 4 ... Induction heating coil (excitation coil)
5 ... Lagent heater 6 ... Top frame 7 ... Kitchen equipment stand (sink)
7A ... Top plate 8, 9 ... Cooking container placement part 10 ... Cooking container (pot)
13 ... Operation switch part 13A ... Power switch 13B ... Fried food switch 16 ... Exhaust part 17 ... Exhaust cover 19 ... Coil spring 20 ... Base member 21 ... .... Coil spring 25 ... Circuit board 27 ... Radiation member 28 ... Exhaust slit 30 ... Control device 31 ... Resonance capacitor 32 ... Resonance circuit 33 ... Commercial power supply 34 ... Rectifier circuit 35A ... Switching element 35B ... Switching element 36 ... Inverter circuit 37A, 37B ... Drive circuit 38 ... Control unit 39 ... Temperature Detection circuit 40 ... Current detection circuit 41 ... Voltage detection circuit 42 ... A / D conversion circuit 43 ... CPU
44 ... ROM
45 ... RAM
Pan bottom TH ... Sensor for temperature detection Coil TH ·· Sensor for temperature detection

Claims (2)

A switching element is provided to control energization to the excitation coil arranged under the top plate of the electromagnetic cooker body, and the drive circuit for driving the switching element and the excitation signal supplied to the excitation coil are supplied to the excitation coil Electromagnetic cooker comprising a control unit for controlling the high frequency power to be brought close to the target power value, and maintaining the oil in the cooking container (or pan) placed on the top plate at a predetermined temperature In
An electromagnetic cooker comprising size determining means for determining the size of the cooking container (or pan) based on a difference in temperature detected by temperature detection sensors arranged at different positions in the radial direction of the excitation coil.   The temperature detection sensor includes a first temperature detection sensor disposed at a central portion of the excitation coil, and a second temperature detection sensor disposed at an intermediate portion in the radial direction of the excitation coil. The electromagnetic cooker according to claim 1, wherein the size of the cooking container (or pan) is determined based on a difference between detected temperatures of the first and second temperature detection sensors.

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