JP5999998B2 - Induction heating cooker and its program - Google Patents

Description

  The present invention relates to an induction heating cooker provided with an infrared temperature sensor that detects the amount of infrared rays emitted from an object to be heated and measures temperature, and a temperature sensor that detects the temperature of the top plate, and induction heating cooking thereof The present invention relates to a program for executing control of a container.

  Conventionally, what detects the temperature of the pan which is a to-be-heated object with an infrared sensor, and changes setting heat power with the amount of amplification of the detection temperature of an infrared sensor is known (for example, refer to patent documents 1).

JP 2012-22854 A (3rd page, FIG. 1)

  However, according to the conventional technology, in the case of continuous heating, the temperature of the top plate is increased by the heat generated by the heated pan, and the infrared sensor is affected by the increased temperature of the top plate. Will receive. Therefore, when the temperature of the top plate is high at the start of heating, the detection start temperature of the infrared sensor is already high, and the set thermal power is varied by the amount of amplification from that, so the temperature detected by the infrared sensor even when the pan temperature is high There is a problem that the temperature does not reach the predetermined amplification amount easily, and when the amplification amount reaches the predetermined value, the pan is at a dangerous temperature.

  The present invention has been made in view of the above problems, and detects the temperature of the top plate at the start of heating, sets a threshold for changing the heating power setting according to the temperature of the top plate at the start of heating, and It is an object of the present invention to provide an induction heating cooker for controlling the heating power so as not to reach a dangerous temperature at which the temperature is deformed, and a control program therefor.

An induction heating cooker of the present invention that solves the problem includes a top plate on which an object to be heated is placed, an inner heating coil that is disposed below the top plate and that is disposed near the center and that can be energized independently, A heating means for inductively heating an object to be heated by energizing a high-frequency current through an induction heating coil that is arranged around the heating coil and can be energized independently, and a high-frequency current is supplied to the inner heating coil A substrate on which a first inverter circuit and a second inverter circuit for supplying a high-frequency current to an external heating coil are mounted; an input means capable of inputting an operation start of the heating means; a first inverter circuit; a second inverter circuit; control means for controlling the input means and the inverter circuit and the heating means, timing means for measuring an energization time of the heating means, a plurality of temperature sensors for detecting the temperature of the top plate, the infrared radiated from the heated object An infrared sensor for detecting the temperature by the amount of, and a heating mode with a preheating step for preheating to a temperature suitable for cooking an object to be heated, a plurality of temperature sensors and infrared sensors, internal heating coil periphery is disposed on the inner side of the control means, when the heating mode is initiated by the input means is detected by the plurality of temperature sensors, according to the initial temperature of the temperature before the top plate to be supplied to the heating means Then , a threshold for determining whether or not the heating power setting of the heating means can be changed is set, and the initial temperature is an average value of the temperature of the top plate before the heating means is energized, and is detected by the infrared sensor. allowed to continue preheating step when the time until the temperature reaches the threshold value of the top plate or the heated object after energization in a predetermined time-consuming than a predetermined judgment time, when it is less than a predetermined determination time is pre A process in which was to make the end of the.

  According to the present invention, the object to be heated is deformed because the control means sets the threshold value for determining whether or not to change the heating power setting of the heating means according to the initial temperature of the top plate. The threshold value can be set so as not to reach such a temperature, and the safety of the induction heating cooker is improved.

It is a perspective view which shows the structure of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a perspective view of the state which removed the top plate which shows the structure of the induction heating cooking appliance concerning Embodiment 1 of this invention. It is the schematic sectional drawing seen from the front side of the induction heating cooking appliance concerning Embodiment 1 of the present invention. It is a block diagram which shows the basic composition of the whole induction heating cooking appliance which concerns on Embodiment 1 of this invention. (A) Top view which shows one Example of the induction heating coil of the induction heating cooking appliance which concerns on Embodiment 1 of this invention, (b) Of the induction heating coil of the induction heating cooking appliance which concerns on Embodiment 1 of this invention It is a top view which shows another Example. It is a flowchart of the control program which shows the basic operation | movement of the heating control of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a continuation of the flowchart of the control program which shows the basic operation | movement of the heating control of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows an example of the control conditions of the heating control of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a temperature graph which shows an example of determination of the induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is a flowchart of the control program which shows the basic operation | movement of the heating control of the induction heating cooking appliance which concerns on Embodiment 2 of this invention. It is a continuation of the flowchart of the control program which shows the basic operation | movement of the heating control of the induction heating cooking appliance which concerns on Embodiment 2 of this invention. It is a temperature graph which shows an example of the determination of the induction heating cooking appliance which concerns on Embodiment 2 of this invention.

Embodiment 1
(Constitution)
1 is a perspective view showing a configuration of an induction heating cooker according to Embodiment 1 of the present invention, and FIG. 2 is a state in which a top plate showing a configuration of the induction heating cooker according to Embodiment 1 of the present invention is removed. FIG. 3 is a schematic sectional view seen from the front side of the heating cooker according to the first embodiment of the present invention, and FIG. 4 shows the basic configuration of the entire induction heating cooker according to the first embodiment of the present invention. FIG. 5 (a) is a plan view showing an example of an induction heating coil of the induction heating cooker according to Embodiment 1 of the present invention, and FIG. 5 (b) is related to Embodiment 1 of the present invention. It is a top view which shows the other Example of the induction heating coil of an induction heating cooking appliance.
Hereinafter, the structure of the heating cooker according to the first embodiment of the present invention will be described with reference to FIGS.
Note that in each drawing, the same reference numerals are given to the same portions or corresponding portions, and a part of the description may be omitted.

  As shown in FIG. 1, the induction heating cooker 100 according to the first embodiment of the present invention is a non-magnetic material, for example, a crystal, on which a cooked object 10 such as a pot can be placed on the top surface of the main body 1. There is provided a top plate 2 made of a vitrified glass and a top plate 4 comprising a frame 3 made of metal, for example, stainless steel, which is fixed to the outer periphery of the top plate 2 with a silicon adhesive (not shown). Then, the top panel 4 is provided with an upper surface operation unit 5 for performing various operation inputs, and a front operation unit 6 for performing various operation inputs on the front surface of the main body 1 and a power switch 7 for turning on / off the heating cooker. ing.

  Reference numeral 8 denotes a cooking chamber in which an object to be cooked such as fish is placed and grill cooking or oven cooking is performed. As shown in FIG. 3, radiation heating means 15a and 15b are disposed inside.

The front surface of the cooking chamber 8 is opened, and the cooking chamber door 9 for closing the opening of the space in which the above-described radiation heating means 15a and 15b are disposed is drawn forward at the front opening of the cooking chamber 8. It is provided freely.

  The cooking cabinet door 9 is adapted to be able to pull out a placing plate (not shown) and a grill (not shown) on which the object to be cooked is linked in conjunction with the drawer, and the cooking cabinet door 9 is pushed in most. In this state, the front opening of the cooking chamber 8 is closed and cooking can be performed. An operation input for cooking can be performed from the upper surface operation unit 5 or the front operation unit 6.

  In the main body 1 below the top plate 2, three heating means are arranged as shown in FIG. 2, each of which is an induction heating means comprising an induction heating coil, 11 is a left induction heating means, and 12 is a right induction. A heating means 13 is a central induction heating means. Thus, what was provided with three heating means is called a three-neck type induction heating cooking appliance.

  Here, the induction heating means means a heating means using the principle of electromagnetic induction. When a high-frequency alternating current is applied to the induction heating coil, a rotating magnetic field line is generated, and a uniform magnetic field is generated inside the induction heating coil. Occur. When the magnetic field penetrates the induction heating coil, a magnetic field that disturbs the magnetic flux change is generated inside the induction heating coil, and an eddy current flows through the object to be heated and continues to flow by applying a high-frequency AC current, for example, an AC current of 20 to 90 kHz. Therefore, it is a heating method in which the heated object generates heat by generating Joule heat due to the electric resistance and eddy current of the heated object.

In the above description, an example in which three induction heating means are provided has been described. However, in an induction heating cooker in which three heating means are provided, one of them is a heating means that is not an induction heating means, for example, a radiant. It may be constituted by a radiant heating means made of a heating wire such as a heater, and can be appropriately selected. Further, the number of heating means is not limited to three and may be two, and the combination of the heating means in that case can be appropriately selected from induction heating means and radiant heating means.

  Further, as shown in FIG. 2, display means 17a, display means 17b, and display means 17c are provided below the top plate 2, and the display means 17a includes display windows 2a and display means 17b provided on the top plate 2. The display contents of the display window 2b and the display means 17c are visible through the display window 2c.

The display means here is a liquid crystal (LCD) or various light emitting elements (LED (Light Emitting Diode), LD (Laser Diode) are examples of semiconductor light emitting elements) unless otherwise specified). In addition, it is configured by any one of display means such as an organic electroluminescence (EL) element.

Furthermore, the display on the above-mentioned display means means that the user can know the operating conditions of the cooking device and the reference information for cooking by changing the characters, symbols, illustrations, colors, presence or absence of light emission (or lighting), light emission luminance, etc. This is a visual notification.

A control including a control unit 22 (described later) made up of electronic components in addition to the cooking chamber 8 in the space below the shielding plate 14 below the left induction heating unit 11, the right induction heating unit 12, and the central induction heating unit 13. An inverter board 16a including an inner heating coil inverter circuit 23 and an outer heating coil inverter circuit 24, which will be described later, which are configured from a switching element, a rectifier circuit, and other electronic components (not shown) is disposed.

In addition, arrangement | positioning of a board | substrate shows an example, Comprising: It is not limited to this arrangement | positioning, Arrangement | positioning of a control board and an inverter board | substrate can be suitably changed with a main body structure.

  As shown in FIGS. 4 and 5 (a), the left induction heating means 11 is a main heating coil which is an induction heating coil which is provided in series with a predetermined space and connected in series and can be energized independently. 11c and an inner heating coil 11b composed of a main heating coil 11d, and an induction heating coil that is provided with a predetermined space between the inner heating coil 11b and can be energized independently of the inner heating coil 11b. An external heating coil 11a is provided.

A plurality of temperature detecting means are disposed in the space between the main heating coil 11c and the main heating coil 11d. Reference numerals 20a and 20b denote heat transfer type temperature sensors such as a thermistor for detecting the temperature by heat transfer in contact with the temperature measurement object.

The temperature sensor 20c is an infrared sensor composed of a photodiode or the like that can measure the temperature by detecting the amount of infrared rays emitted from the heated object 10 such as a pan and transmitted through the top plate 2 in a non-contact manner.

The infrared sensor 20c aggregates infrared rays radiated from the object to be heated 10, and can receive the temperature in real time (with little time difference) and detect the temperature from the amount of infrared rays. It is superior to the temperature sensors 20a and 20b.

The heat transfer type temperature sensors 20a and 20b are inferior in that they capture a rapid temperature change in real time as compared with the infrared sensor 20c. However, the heat transfer type temperature sensors 20a and 20b receive radiant heat from the top plate 2 or the object to be heated 10 and It is superior to the infrared sensor 20c in that the temperature of the top plate 2 directly below it can be detected reliably. Further, since heat transfer can be detected, the temperature of the top plate 2 can be detected even when the article to be heated 10 is moved.

As described above, since the heat transfer type temperature sensors 20a and 20b and the infrared sensor 20c have excellent points, the temperature detection accuracy can be improved by using them in combination.

It is desirable that the heat transfer type temperature sensors 20a and 20b and the infrared sensor 20c be disposed in the vicinity of an induction heating coil that can be energized alone. By being arranged close to the induction heating coil that becomes high temperature, the responsiveness of temperature detection is improved, and the detection accuracy can be further improved.

Further, in the configuration of the induction heating coil in which the inner heating coil 11b and the outer heating coil 11a are provided independently as shown in FIG. 5A, the inner heating coil 11b, which is an induction heating coil at least near the center, It is desirable to be able to energize alone.

If the inner heating coil 11b can be energized independently, when the outer heating coil 11a is larger than the maximum diameter of the small-diameter heating object when the small-diameter heating object is to be heated, the outer heating coil 11a is energized. Without wasting, it is possible to suppress wasteful power consumption by energizing only the inner heating coil 11b.

Although the left induction heating means 11 has been described here, the right induction heating means 12 is not shown, but similarly, a main heating coil 12c and a main heating coil 12d that are provided in series with a predetermined space therebetween and connected in series. An inner heating coil 12b, and an outer heating coil 12a that is provided with a predetermined space between the inner heating coil 12b and can be energized independently of the inner heating coil 12b. A thermal temperature sensor and an infrared sensor 20c are provided.

Further, in the first embodiment of the present invention, the temperature detection means is two heat transfer type temperature sensors and one infrared sensor, which is three in total. However, the present invention is not limited to this, and one heat transfer type temperature sensor and two infrared sensors 2 are used. A combination of the two or a heat transfer type temperature sensor and an infrared sensor may be further increased, and thereby the temperature detection accuracy can be further improved.

Furthermore, in the first embodiment of the present invention, the temperature detection means is disposed in the space between the main heating coil 11c and the main heating coil 11d, but the present invention is not limited to this. You may arrange | position in the space between the heating coils 11a, and may arrange | position in both of those spaces.

In the first embodiment of the present invention, as shown in FIG. 5 (a), the left induction heating means 11 is an internal heating composed of a main heating coil 11c and a main heating coil 11d provided in series with a predetermined space therebetween. Although the coil 11b and the inner heating coil 11b are separated from the inner heating coil 11b and provided with a predetermined space and can be energized independently, the example shown in FIG. ), A main heating coil 11c including a main heating coil 11c and a main heating coil 11d provided in series with a predetermined space therebetween, and an internal heating coil 11b provided with a predetermined space therebetween. A plurality of external heating cores such as an outer coil 1 (30a), an outer coil 2 (30b), an outer coil 3 (30c), and an outer coil 4 (30d) that can be energized independently of the coil 11b. It may be constituted by Le.

(Operation)
Next, an example of cooking control of the induction heating cooker according to Embodiment 1 of the present invention will be described with reference to FIGS. Here, the case where the left induction heating means 11 is operated will be described as an example.
FIG. 6 is a flowchart of a control program showing the basic operation of the heating control of the induction heating cooker according to Embodiment 1 of the present invention, and FIG. 7 is the heating control of the induction heating cooker according to Embodiment 1 of the present invention. FIG. 8 is an explanatory diagram showing an example of control conditions for heating control of the induction heating cooker according to the first embodiment of the present invention, and FIG. 9 is an implementation of the present invention. It is a temperature graph which shows an example of the determination of the induction heating cooking appliance which concerns on the form 1.

  An operation input from an operation key (not shown) provided in the upper surface operation unit 5 (see FIGS. 1 and 4) is sent to a control means 22 including a computer (not shown), and a control program is activated to input information. Is displayed on the display means 17a, and heating is started as shown in FIG. 6 (S1).

  Next, the initial temperature TH0 of the top plate 2 at the start of cooking is detected by the heat transfer type temperature sensors 20a and 20b, and a signal is sent to the control means 22 (S2). Here, the control means 22 calculates the average value of the temperatures from the temperature signals detected by the heat transfer temperature sensors 20a and 20b, respectively, and the average value is set as the initial temperature TH0 (hereinafter sometimes referred to as TH0).

However, TH0 does not necessarily have to be set as an average value, and the highest temperature or the lowest temperature of a plurality of heat transfer type temperature sensors may be used as the initial temperature.

  Next, whether TH0 detected in S2 and the predetermined coefficient a and coefficient b prepared in advance are calculated using a preset calculation formula “coefficient a × initial temperature TH0 + coefficient b”, and the thermal power setting is changed. A threshold value Ta (hereinafter referred to as Ta) for determining whether or not is set is set (S3).

Since Ta is set by the detected TH0, Ta corresponding to TH0 is set as shown in the graph of FIG. 9, so the value of Ta does not become one fixed value. In addition, Ta is set according to a low temperature if the initial temperature is low, and according to a high temperature if the initial temperature is high, so that even when used immediately after another cooking, control suitable for the state can be performed.

The above-mentioned calculation formula “coefficient a × initial temperature TH0 + coefficient b” is set by repeatedly performing a temperature detection test using heated objects such as various types of pans having different heat capacities or flat frying pans and cooking plates (iron plates). Is.

In FIG. 9, (a) shows a small heat capacity, for example, a heated object such as a thin plate pan, (b) shows a large heat capacity, such as a thick frying pan, and (c) shows a large heat capacity. FIG. 4 shows an example of measured values of an object to be heated such as a thick wok. Even if the object to be heated has a large heat capacity, the measurement results are different between the frying pan and the wok as in (a) and (c). From these actual measurement results, the calculation formula “coefficient a × initial temperature TH0 + coefficient b” is set.

Here, the heat capacity will be explained. The heat capacity is the amount of heat required to raise the temperature of the object by a unit temperature. That is, the greater the heat capacity, the more heat is required to raise the temperature of the object.

Therefore, a thick frying pan with a large heat capacity takes more time than a thin pan with a small heat capacity when raising the temperature with the same thermal power, and a thicker pan with a large heat capacity when trying to raise the temperature in the same time. The frying pan needs to be heated with higher heating power.

In other words, if a thick frying pan and a thin plate pan with different heat capacities are heated with the same heating power, the thin plate pan will be overheated with the heating power suitable for the frying pan, and the frying pan will be underheated with the heating power suitable for the thin plate pan. .

Therefore, the setting of the thermal power is changed according to the threshold Ta, and the measured temperature is lower than the threshold Ta as shown in the graph of FIG. 9 (b), (c), and a large heat capacity such as a frying pan or a wok Objects are heated with normal (higher) thermal power, and heated objects with a small heat capacity, such as a thin plate pan with a high measurement temperature (A), are heated with lower thermal power than normal (higher) thermal power. Heating suitable for the object to be heated can be performed.

  When Ta is set in S3, the preheating process is started, and driving is instructed from the control means 22 to the inner heating coil inverter circuit 23 and the outer heating coil inverter circuit 24, and the inner coil 11b and the outer coil 11a are energized respectively. The left induction heating unit 11 is energized (S4).

In the preheating process, a plurality of set temperatures can be selected. For example, as shown in FIG. 8, three set temperatures of 160 ° C., 190 ° C., and 220 ° C. can be selected. Setting of thermal power and selection of power input coil are done.

Further, the preheating process will be described in more detail. As shown in FIG. 8, a preheating mode (1) to (3) for transitioning in the process is provided, and a predetermined time has elapsed since the start of the process (1). Then, the process proceeds with (2) and (3). When the set temperature is 160 ° C., the process proceeds to (2), and when the set temperature is 190 ° C. and 220 ° C., the process proceeds to (3). It has become.

  Simultaneously with the start of energization of the left induction heating unit 11, a measurement instruction is issued from the control unit 22 to the time measuring unit 21, and the elapsed time from the start of energization of the left induction heating unit 11 is measured (S5).

  Next, a preset preheating process limit temperature Tb (hereinafter referred to as Tb) is compared with a temperature TIR (hereinafter referred to as TIR) detected by the infrared sensor 20c (S6).

In the first embodiment of the present invention, the temperature value detected by the infrared sensor 20c is used as it is as TIR, but the temperature value detected by the infrared sensor 20c is corrected by a predetermined coefficient is used as TIR. You may do it.

When TIR is equal to or greater than Tb in S6, the process proceeds to S9 and the preheating process is completed. If TIR is lower than Tb in S6, the process proceeds to S7. If the TIR is greater than or equal to Ta in S7, the process proceeds to S8, and if the TIR is lower than Ta, the process returns to S6.

  In S8, the elapsed time from the start of energization of the left induction heating means 11 whose measurement is started in S5 is compared with a preset determination time TimeA (hereinafter referred to as TimeA).

Time A is set for determining the object to be heated, and by comparing the elapsed time with Time A, it is determined whether the object to be heated 10 has a large heat capacity or a small heat capacity. . If the elapsed time until TIR is less than Tb and Ta or more is Time A or less, it is determined that the heat capacity is small, and if it is greater than Time A, it is determined that the heat capacity is large.

  As described above, if the elapsed time is equal to or less than Time A in S8, it is determined that the heat capacity is small, the preheating process is completed (S9), the heat retaining process is entered, and heating is turned on (S10). The thermal power input by heating in S10 is a thermal power corresponding to an object to be heated with a small heat capacity, and is heated with a thermal power smaller than a normal heat retaining thermal power input in S23 described later.

Also in the heat retaining process, three set temperatures of 160 ° C., 190 ° C., and 220 ° C. can be selected, and the time, heating power setting, and power input coil suitable for each set temperature are selected. In the heat retention step of S10, as shown in FIG. 8, the operation is performed by heating (6) with a thermal power corresponding to an object to be heated having a small heat capacity. In the heat retention step of S23 to be described later, the operation is performed by (5) heating with a heating power corresponding to a normal object to be heated which is larger than the heating power of (6).

(A), (b), and (c) shown in FIG. 9 are the sections of the preheating process mode (1) (time: 20 seconds, thermal power: 1000 W, power input coil: inner coil) shown in FIG. When an unloaded object to be heated is heated, the temperature of the heat transfer temperature sensors 20a and 20b at the start of the X-axis, the temperature of the infrared sensor 20c at the end of the Y-axis, or the temperature of the object to be heated is about 300 It is a graph of the relationship between the temperature of the infrared sensor 20c when the temperature is higher than or equal to ° C.

The temperature of the infrared sensor 20c varies depending on the type of the object to be heated. An object to be heated having a large heat capacity (for example, a frying pan having a thick plate) does not easily increase the temperature of the infrared sensor 20c, and an object to be heated having a small heat capacity (for example, a thin pan on a plate) is likely to increase the temperature of the infrared sensor 20c. .

  Next, in S11, TIR is compared with a preset heat retention process limit temperature Tc (hereinafter referred to as Tc). When TIR is equal to or greater than Tc, the process proceeds to S14 and heating is turned off.

If the TIR is lower than Tc in S11, the process proceeds to S12, and if the predetermined heat retention process time set in advance has elapsed, the process proceeds to S13 to complete the heat retention process. If the predetermined heat retention process time has not elapsed, the process returns to S11, and the operation from S11 is executed again.

In step S11, if TIR is equal to or greater than Tc, the process proceeds to step S14. After the heating is turned off, it is determined whether or not a predetermined heat retention process time set in advance has elapsed (S15). If the predetermined heat retention process time has elapsed, the process proceeds to S13, the notification means (not shown) is notified of completion of the heat retention process, and the heat retention process is completed.

Note that the notification means an operation for notifying the user of related information by display or electrical sound (referred to as an electrically generated or synthesized sound), and the notification means unless otherwise specified. It includes notification means using audible sounds such as a buzzer and a speaker, and notification means using characters, symbols, figures, animation, or visible light.

  If the predetermined heat retention process time has not elapsed in S15, it is determined whether or not the heating power for heating is applied (S16). If the TIR is lower than Tc in S17, the heating is turned on with the thermal power corresponding to the object to be heated having the same heat capacity as before the heating is turned off in S14 (S18), the process returns to S11, and the operation from S11 is executed again. .

  If the TIR is not lower than Tc in S17, the process returns to S14, the heating OFF is continued, and the operations after S15 are executed again.

  If the elapsed time is not equal to or less than Time A in S8, it is determined that the object to be heated 10 has a large heat capacity, and preheating is continued (S19).

  Next, Tb and TIR are compared (S20). When TIR is Tb or more in S20, S21 is skipped and it progresses to S22 and completes a preheating process (S22).

If the TIR is lower than Tb in S20, the process proceeds to S21, and it is determined whether or not a predetermined preheating process time set in advance has elapsed. When the predetermined preheating process time has not elapsed, the process returns to S19 and the preheating process is continued.

  If the predetermined preheating process time has elapsed in S21, the process proceeds to S22 and the preheating process is completed. When the preheating process is completed, the heat retaining process is started (S23). In this heat retaining process, the heating power is higher than that of the heat retaining process of S10, and is heated with a thermal power corresponding to a normal object to be heated.

  Next, TIR and Tc are compared (S24). If the TIR is equal to or greater than Tc, the process proceeds to S27 and the heating is turned off.

If the TIR is lower than Tc in S24, the process proceeds to S25, and if the predetermined heat retention process time set in advance has elapsed, the process proceeds to S26 and the heat retention process is completed. If the predetermined heat retention process time has not elapsed, the process returns to S24, and the operation from S24 is executed again.

In S24, when TIR is equal to or greater than Tc, the process proceeds to S27, and after the heating is turned off, it is determined whether or not a predetermined heat retention process time set in advance has elapsed (S28). If the predetermined heat retention process time has elapsed, the process proceeds to S26, where the notifying means (not shown) notifies the completion of the heat retention process by sound or voice to complete the heat retention process.

  If the predetermined heat retention process time has not elapsed in S28, it is determined whether or not the heating power for heating is applied (S29). If the TIR is lower than Tc in S30, the heating is turned on with the same heating power corresponding to the normal object to be heated before the heating is turned off in S27 (S31), the process returns to S24, and the operations from S24 are executed again.

  If the TIR is not lower than Tc in S30, the process returns to S27, the heating OFF is continued, and the operations after S28 are executed again.

In Embodiment 1 of the present invention, it is determined that the heat capacity is small and the preheating process is completed, and the heat entering process is entered and heating is turned on. However, the object to be heated is not suitable for the preheating mode because the heat capacity is small. The safety can be improved even if it is determined and the heating is stopped or the set heating power is lowered to notify the user with a buzzer or voice so that the user can understand.

As described above, in the induction heating cooker according to the first embodiment of the present invention, from the initial temperature of the top plate detected by the heat transfer type temperature sensor, a threshold for determining whether or not the heating power setting can be changed according to the initial temperature. Since the threshold is set according to the low temperature if the initial temperature is low, and the high temperature if the initial temperature is high, control suitable for that state is possible even if it is used immediately after other cooking. Thus, safety is improved without the object to be heated reaching a dangerous temperature.

If the temperature of the object to be heated detected by the infrared sensor reaches the set threshold value, the preheating process with a high thermal power is continued if the threshold value is not reached within a predetermined time. When the threshold value is reached, the preheating step is completed, so that the object to be heated is not heated with excessively high heating power, and safety is improved.

Furthermore, if the temperature of the object to be heated detected by the infrared sensor does not reach the threshold value within a predetermined time due to the elapsed time until the temperature reaches the set threshold value, the preheating process with high thermal power is continued. When the threshold value is reached, the preheating process is completed and the process proceeds to a heat retention process having a lower heating power than the preheating process, so that the object to be heated is not heated with an excessively high heating power and the safety is improved.

Embodiment 2
(Operation)
10 is a flowchart of a control program showing the basic operation of the heating control of the induction heating cooker according to the second embodiment of the present invention, and FIG. 11 is the heating control of the induction heating cooker according to the second embodiment of the present invention. FIG. 12 is a temperature graph showing an example of the determination of the induction heating cooker according to the second embodiment of the present invention.
10-12, an example of the heating control of the induction heating cooking appliance which concerns on Embodiment 2 of this invention is demonstrated. Here, as in the first embodiment of the present invention, the case where the left induction heating means 11 is operated will be described as an example.
In addition, since the structure of the induction heating cooking appliance concerning Embodiment 2 of this invention is the same as the structure of the induction heating cooking appliance concerning Embodiment 1 of this invention, description about a structure is abbreviate | omitted.

  An operation input from an operation key (not shown) provided in the upper surface operation unit 5 (see FIGS. 1 and 4) is sent to a control means 22 including a computer (not shown), and a control program is activated to input information. Is displayed on the display means 17a, and heating is started as shown in FIG. 10 (S41).

  Next, the initial temperature TH0 of the top plate 2 at the start of cooking is detected by the heat transfer type temperature sensors 20a and 20b, and a signal is sent to the control means 22 (S42). Here, as in the first embodiment, the control means 22 calculates the average temperature value from the temperature signals detected by the heat transfer temperature sensors 20a and 20b, and the average value is described as the initial temperature TH0 (hereinafter referred to as TH0). There are things).

However, as in the first embodiment of the present invention, it is not always necessary to set TH0 as an average value. The highest temperature or the lowest temperature of a plurality of heat transfer temperature sensors is used as the initial temperature. You may make it use.

  Next, whether TH0 detected in S42 and predetermined coefficient a and coefficient b prepared in advance are calculated using a preset calculation formula “coefficient a × initial temperature TH0 + coefficient b” to change the thermal power setting. A threshold value Ta (hereinafter referred to as Ta) for determining whether or not is set is set (S43).

Since Ta is set by TH0 detected in the same manner as in the first embodiment of the present invention, Ta corresponding to TH0 is set as shown in the graph of FIG. 12, so the value of Ta is fixed 1 It will not be one value. In addition, Ta is set according to a low temperature if the initial temperature is low, and according to a high temperature if the initial temperature is high, so that even when used immediately after another cooking, control suitable for the state can be performed.

The above-mentioned calculation formula “coefficient a × initial temperature TH0 + coefficient b” is set by repeatedly performing a temperature detection test using heated objects such as various types of pans having different heat capacities or flat frying pans and cooking plates (iron plates). Is. (A) shown in the graph of FIG. 12 has a small heat capacity, for example, a heated object such as a thin plate pan, (b) a large heat capacity, for example, a heated object such as a thick frying pan, (c) a large heat capacity, For example, an example of a measured value of an object to be heated such as a thick wok is shown. Even if the object to be heated has a large heat capacity, the measurement results are different between the frying pan and the wok as in (a) and (c). From these actual measurement results, the calculation formula “coefficient a × initial temperature TH0 + coefficient b” is set.
Note that the explanation about the heat capacity is the same as that of the first embodiment, and is omitted here.

  When Ta is set in S43, a preheating process is started, and driving is instructed from the control means 22 to the inner heating coil inverter circuit 23 and the outer heating coil inverter circuit 24, and the inner coil 11b and the outer coil 11a are energized respectively. The left induction heating unit 11 is energized (S44).

In the preheating process, a plurality of preset temperatures can be selected as in the first embodiment of the present invention. For example, as shown in FIG. 8, three preset temperatures of 160 ° C., 190 ° C., and 220 ° C. can be selected. Thus, the time suitable for the set temperature, the setting of the heating power, and the selection of the power input coil are made.

Further, the preheating process will be described in more detail. As shown in FIG. 8, a preheating mode (1) to (3) for transitioning in the process is provided, and a predetermined time has elapsed since the start of the process (1). Then, the process proceeds to (2) and (3). When the set temperature is 160 ° C., the process proceeds to (2). When the set temperature is 190 ° C. and 220 ° C., the process proceeds to (3). It has become.

  Simultaneously with the start of energization of the left induction heating means 11, a measurement instruction is issued from the control means 22 to the time measuring means 21, and the elapsed time from the start of energization of the left induction heating means 11 is measured (S45).

  Next, the preset preheating process limit temperature Tb (hereinafter referred to as Tb) is compared with the temperature TIR detected by the infrared sensor 20c (S46).

When TIR is equal to or greater than Tb in S46, the process proceeds to S49 and the preheating process is completed. If TIR is lower than Tb in S46, the process proceeds to S47. When the increase value ΔTIR (hereinafter referred to as ΔTIR) of Ta and the temperature TIR detected by the infrared sensor 20c in S47 is compared, if ΔTIR is equal to or greater than Ta, the process proceeds to S48, and ΔTIR is lower than Ta Returns to S46.

In the second embodiment of the present invention, the increase value of the temperature TIR detected by the infrared sensor 20c at a predetermined time is ΔTIR, but the value obtained by correcting the numerical value of the temperature detected by the infrared sensor 20c by a predetermined coefficient is TIR. A value obtained by increasing the corrected TIR in a predetermined time may be used as ΔTIR.

  In S48, the elapsed time from the start of energization of the left induction heating means 11 that has started measurement in S45 is compared with a preset determination time TimeA (hereinafter referred to as TimeA).

  As described above, if the elapsed time is equal to or less than Time A in S48, it is determined that the heat capacity is small, the preheating process is completed (S49), the heat retaining process is entered, and heating is turned on (S50). The thermal power input by the heating of S50 is a thermal power corresponding to an object to be heated having a small heat capacity, and is heated by a thermal power smaller than a normal heat retaining thermal power input in S63 described later.

Also in the heat retaining process, three set temperatures of 160 ° C., 190 ° C., and 220 ° C. can be selected, and the time, heating power setting, and power input coil suitable for each set temperature are selected. In the heat retaining step of S50, as shown in FIG. 8, the operation is performed by heating (6) with a thermal power corresponding to an object to be heated having a small heat capacity. In the heat retaining step of S63, which will be described later, the operation is performed in (5) in which heating is performed with a thermal power corresponding to a normal object to be heated that is larger than the thermal power in (6).

(A), (b), (c) shown in FIG. 12 described above is a mode (1) (time: 20 seconds, thermal power: 1000 W, power application coil: inner coil) section of the preheating process shown in FIG. When an unloaded object to be heated is heated, the temperature of the heat transfer temperature sensors 20a and 20b at the start of the X-axis, the temperature of the infrared sensor 20c at the end of the Y-axis, or the temperature of the object to be heated is about 300 It is a graph of the relationship between the temperature of the infrared sensor 20c when the temperature is higher than or equal to ° C.

The temperature rise value of the infrared sensor 20c varies depending on the type of the object to be heated. An object to be heated with a large heat capacity (for example, a frying pan with a thick plate) is unlikely to have a high temperature rise value of the infrared sensor 20c, and an object to be heated with a small heat capacity (for example, a thin pan with a plate) The rising value tends to be high.

  Next, in S51, TIR is compared with a preset heat retention process limit temperature Tc (hereinafter referred to as Tc). If the TIR is equal to or greater than Tc, the process proceeds to S54 and the heating is turned off.

If the TIR is lower than Tc in S51, the process proceeds to S52, and if the predetermined heat retention process time set in advance has elapsed, the process proceeds to S53 to complete the heat retention process. If the predetermined heat retention process time has not elapsed, the process returns to S51, and the operation from S51 is executed again.

In S51, when TIR is equal to or greater than Tc, the process proceeds to S54. After the heating is turned off, it is determined whether or not a predetermined heat retention process time set in advance has elapsed (S55). If the predetermined heat retention process time has elapsed, the process proceeds to S53 to notify the notifying means (not shown) of the completion of the heat retention process and complete the heat retention process.

  If the predetermined heat retention process time has not elapsed in S55, it is determined whether or not the heating power for heating is to be applied (S56). If the TIR is lower than Tc in S57, the heating is turned on with the thermal power corresponding to the object to be heated having the same heat capacity as before the heating is turned off in S54 (S58), the process returns to S51, and the operation from S51 is executed again. .

  If the TIR is not lower than Tc in S57, the process returns to S54, the heating OFF is continued, and the operations after S55 are executed again.

  If the elapsed time is not equal to or less than Time A in S48, it is determined that the object to be heated 10 has a large heat capacity, and preheating is continued (S59).

  Next, Tb and TIR are compared (S60). If TIR is equal to or greater than Tb in S60, S61 is skipped and the process proceeds to S62 to complete the preheating process (S62).

When the TIR is lower than Tb in S60, the process proceeds to S61, and it is determined whether or not a predetermined preheating process time set in advance has elapsed. If the predetermined preheating process time has not elapsed, the process returns to S59 and the preheating process is continued.

  If the predetermined preheating process time has elapsed in S61, the process proceeds to S62 and the preheating process is completed. When the preheating process is completed, the heat retaining process is started (S63). In this heat retaining step, the heating is performed with a thermal power that is higher than the thermal power of the heat retaining step of S50 and that corresponds to a normal object to be heated.

  Next, TIR and Tc are compared (S64). If the TIR is equal to or greater than Tc, the process proceeds to S67 and the heating is turned off.

If the TIR is lower than Tc in S64, the process proceeds to S65, and if the predetermined heat retention process time set in advance has elapsed, the process proceeds to S66 to complete the heat retention process. When the predetermined heat retention process time has not elapsed, the process returns to S64, and the operation from S64 is executed again.

In S64, if TIR is equal to or greater than Tc and the process proceeds to S67 and heating is turned off, it is determined whether or not a predetermined heat retention process time set in advance has elapsed (S68). If the predetermined heat retention process time has elapsed, the process proceeds to S66, where the notifying means (not shown) notifies the completion of the heat retention process by sound or voice to complete the heat retention process.

  If the predetermined heat retention time has not elapsed in S68, it is determined whether or not the heating power for heating is to be applied (S69). If the TIR is lower than Tc in S70, the heating is turned on with the same heating power corresponding to the normal heated object before the heating is turned off in S67 (S71), the process returns to S64, and the operation from S64 is executed again.

  If the TIR is not lower than Tc in S70, the process returns to S67 to continue the heating OFF and perform the operations after S68 again.

In the second embodiment of the present invention, it is determined that the heat capacity is small and the preheating process is completed, and the heating process is started and heating is turned on. However, the heating object has a small heat capacity and is not suitable for the preheating mode. The safety can be improved even if it is determined and the heating is stopped or the set heating power is lowered to notify the user with a buzzer or voice so that the user can understand.

As described above, in the induction heating cooker according to the second embodiment of the present invention, from the initial temperature of the top plate detected by the heat transfer type temperature sensor, a threshold for determining whether or not the heating power setting can be changed according to the initial temperature. If the temperature rise value of the object to be heated detected by the infrared sensor for a predetermined time reaches the set threshold value, the thermal power is high if the threshold value is not reached within the predetermined time. Since the preheating step is continued and the preheating step is completed when the threshold is reached within a predetermined time, the object to be heated is not heated with an excessively high heating power, and the safety is improved.

If the temperature rise value of the object to be heated detected by the infrared sensor reaches the set threshold value, the preheating process with high thermal power is continued unless the threshold value is reached within the predetermined time. When the threshold is reached within a predetermined time, the preheating process is completed, and the process proceeds to a heat insulation process that has a lower heating power than the preheating process, so that the object to be heated is not heated with an excessively high heating power. Will improve.

  a coefficient, b coefficient, 1 body, 2 top plate, 2a display window, 2b display window, 2c display window, 3 frame, 4 top plate, 5 upper surface operation section, 6 front operation section, 7 power switch, 8 cooking cabinet , 9 Cooking chamber door, 10 Object to be heated, 11 Left induction heating means, 11a Outer heating coil, 11b Inner heating coil, 11c Main heating coil, 11d Main heating coil, 12 Right induction heating means, 13 Central induction heating means, 14 Shielding plate, 15a Radiation heating means, 15b Radiation heating means, 16a Inverter board, 16b Control board, 17a Display means, 17b Display means, 17c Display means, 20a Heat transfer temperature sensor, 20b Heat transfer temperature sensor, 20c Infrared sensor, 21 Timekeeping means, 22 Control means, 23 Inverter circuit for internal heating coil, 24 For external heating coil Nbata circuit, 30a outer heating coil 1,30b outer heating coil 2,30c outer heating coil 3,30d outer heating coil 4,100 cooker.

Claims (4)

A top plate on which the object to be heated is placed;
An induction heating coil that is arranged below the top plate and is arranged near the center and that can be energized independently, and an external heating coil that is arranged around the inner heating coil and that can be energized independently. Heating means for inductively heating the object to be heated by passing a high-frequency current through
A substrate on which a first inverter circuit that supplies a high-frequency current to the inner heating coil and a second inverter circuit that supplies a high-frequency current to the outer heating coil;
Input means capable of inputting an operation start of the heating means;
Control means for controlling the first inverter circuit, the second inverter circuit, the heating means and the input means;
Timing means for measuring the energization time of the heating means;
A plurality of temperature sensors for detecting the temperature of the top plate;
An infrared sensor that detects the temperature by the amount of infrared rays emitted from the object to be heated;
A heating mode having a preheating step for preheating the object to be heated to a temperature suitable for cooking,
The plurality of temperature sensors and the infrared sensor are disposed inside the outer periphery of the inner heating coil,
The control means includes
When the heating mode is initiated by the input unit, is detected by a plurality of said temperature sensors, in accordance with the initial temperature of the temperature of the top plate before energizing the heating means, the heating power setting of the heating means Setting a threshold for determining whether or not to change, the initial temperature is an average value of the temperature of the top plate before energizing the heating means,
Is detected by the infrared sensor, when the time until the temperature of the top plate or the object to be heated after energization at a predetermined time to the heating means reaches the threshold value according than a predetermined judgment time the preheating step allowed to continue, when it is less than a predetermined determination time is induction heating cooker according to claim <br/> that make terminating the preheating step. A top plate on which the object to be heated is placed;
An induction heating coil that is arranged below the top plate and is arranged near the center and that can be energized independently, and an external heating coil that is arranged around the inner heating coil and that can be energized independently. Heating means for inductively heating the object to be heated by passing a high-frequency current through
A substrate on which a first inverter circuit that supplies a high-frequency current to the inner heating coil and a second inverter circuit that supplies a high-frequency current to the outer heating coil;
Input means capable of inputting an operation start of the heating means;
Control means for controlling the first inverter circuit, the second inverter circuit, the heating means and the input means;
Timing means for measuring the energization time of the heating means;
A plurality of temperature sensors for detecting the temperature of the top plate;
An infrared sensor that detects the temperature by the amount of infrared rays emitted from the object to be heated;
A preheating step for preheating the object to be heated to a temperature suitable for cooking, and a heating mode having a heat retaining step with a lower heating power than the preheating step,
The plurality of temperature sensors and the infrared sensor are disposed inside the outer periphery of the inner heating coil,
The control means includes
When the heating mode is initiated by the input unit, is detected by a plurality of said temperature sensors, in accordance with the initial temperature of the temperature of the top plate before energizing the heating means, the heating power setting of the heating means Setting a threshold for determining whether or not to change, the initial temperature is an average value of the temperature of the top plate before energizing the heating means,
Is detected by the infrared sensor, when the time until the temperature of the top plate or the object to be heated after energization at a predetermined time to the heating means reaches the threshold value according than a predetermined judgment time the preheating step allowed to continue, when it is less than a predetermined determination time is induction heating cooker according to claim <br/> that causes transition to the incubating process ends the preheating step. A top plate on which the object to be heated is placed;
An induction heating coil that is arranged below the top plate and is arranged near the center and that can be energized independently, and an external heating coil that is arranged around the inner heating coil and that can be energized independently. Heating means for inductively heating the object to be heated by passing a high-frequency current through
A substrate on which a first inverter circuit that supplies a high-frequency current to the inner heating coil and a second inverter circuit that supplies a high-frequency current to the outer heating coil;
Input means capable of inputting an operation start of the heating means;
Control means for controlling the first inverter circuit, the second inverter circuit, the heating means and the input means;
Timing means for measuring the energization time of the heating means;
A plurality of temperature sensors for detecting the temperature of the top plate;
An infrared sensor that detects the temperature by the amount of infrared rays emitted from the object to be heated;
A preheating step for preheating the object to be heated to a temperature suitable for cooking, and a heating mode having a heat retaining step with a lower heating power than the preheating step,
The plurality of temperature sensors and the infrared sensor are disposed inside the outer periphery of the inner heating coil,
The control means includes
When the heating mode is initiated by the input unit, is detected by a plurality of said temperature sensors, in accordance with the initial temperature of the temperature of the top plate before energizing the heating means, the heating power setting of the heating means Setting a threshold for determining whether or not to change, the initial temperature is an average value of the temperature of the top plate before energizing the heating means,
The detected by the infrared sensor, when the time until the temperature rise value of the top plate or the object to be heated when energized at a given time to the heating means reaches the threshold value according than a predetermined judgment time The induction heating cooker characterized in that the preheating process is continued , and when the time is equal to or shorter than a predetermined determination time, the preheating process is ended and the process is shifted to the heat retaining process.   The program which makes the said control means perform control of the induction heating cooking appliance as described in any one of Claims 1-3.

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