JP2003319875A - Electromagnetic induction heating cooker and control method for cooking rice using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for automatically cooking rice by using an electromagnetic induction heating cooker equipped with a temperature sensor, and an electromagnetic induction heating cooker equipped with a rice cooking mode. <P>SOLUTION: The electromagnetic induction heating cooker has a temperature sensor and an electromagnetic induction heating coil installed on an underside of a top plate, and is provided with a control section for controlling an output of the coil through an inverter circuit. An operation panel is provided with a means for selecting a rice cooking mode for cooking rice automatically. When the rice cooking mode is selected, the control section executes a processing including the steps (#102-#105) wherein a point of time, when change rate of temperature detected by the sensor reaches a specified temperature or lower after rice cooking is started, is judged to be a point of boiling and a temperature detected at the point of boiling is stored as a temperature at the point of boiling and the steps (#106-#114) wherein a specified additional temperature is added to the temperature at the point of boiling so as to obtain a finish-of- cooking judgment temperature and a transfer to a steaming process is executed when the temperature detected by the sensor exceeds the finish-of-cooking judgment temperature. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an electromagnetic induction heating coil and a temperature sensor disposed below a top plate on which a pan is placed, and controls the output of the electromagnetic induction heating coil based on the temperature detected by the temperature sensor. The present invention relates to a rice cooking control method for automatically cooking rice using an electromagnetic induction heating cooker including a control unit. The present invention also relates to an electromagnetic induction heating cooker having such a rice cooking mode.

[0002]

2. Description of the Related Art An electromagnetic induction heating cooker which utilizes the fact that the pan itself generates heat due to its electric resistance when an eddy current is generated in the pan by an electromagnetic induction heating coil is gradually becoming popular in ordinary households. An electromagnetic induction heating cooker (sometimes called an IH stove) has the advantages of being safer and easier to clean than a heating cooker using gas or the like. Since it is completely covered by a ceramic (heat-resistant glass) top plate called a top plate, even if the pot spills out, it can be cleaned simply by wiping the surface of the top plate.

Further, an electromagnetic induction heating cooker configured to provide a thermistor temperature sensor in the vicinity of the electromagnetic induction heating coil and indirectly measure the temperature of the pan placed on the top plate (via the top plate). (For example, see Japanese Patent Laid-Open No. 2001-307863). This allows
For example, it becomes possible to control the output of the electromagnetic induction heating coil so that the temperature of the oil put in the fryer is kept constant. The inventors studied a control method for performing automatic rice cooking using such an electromagnetic induction heating cooker and a normal pot.

In the conventional electric rice cooker equipped with a microcomputer, the microcomputer automatically adjusts the heating power (electric power adjustment of the heater) in accordance with a rice cooking program stored in advance. In general rice cooking control, the first step, boiling, heats with strong heat,
When boiling is detected, the heating power is weakened and the cooking process starts.
When the cooked food is detected, the heating power is set to zero or a very small one and the process shifts to the purging process.

A temperature sensor contacting the bottom of the inner pot is used for boiling detection and cooking detection in the above rice cooking control. For example, when the rate of increase in the temperature detected by the temperature sensor decreases and becomes smaller than a predetermined value, it is determined that the temperature has boiled, and in the subsequent cooking process, the temperature detected by the temperature sensor has a predetermined temperature (for example, 130 ° C.). )
If it becomes higher, it is determined that cooking is completed, and the process shifts to the unevenness process.

[0006]

In developing a rice cooking control method using an electromagnetic induction heating cooker and an ordinary pot,
The rice cooking control of the electric rice cooker as described above is helpful. However, as described above, in the electromagnetic induction heating cooker, the temperature of the pot is indirectly measured via the top plate by the temperature sensor provided near the electromagnetic induction heating coil. Therefore, not only the detected temperature value is lower than the actual pot temperature,
There is a delay in the change in the temperature detected by the temperature sensor with respect to the actual change in the pot temperature. Also, the change becomes slower.

Therefore, if the rice cooking control of the conventional electric rice cooker is applied as it is to the rice cooking control using the electromagnetic induction heating cooker and the ordinary pot, it is difficult to properly cook the rice, and especially the determination of the cooked rice is performed. It turned out to be difficult as a result of the experiment.

The present invention has been made in view of the above-mentioned conventional problems, and a rice cooking control method for automatically performing rice cooking using an electromagnetic induction heating cooker equipped with a temperature sensor, and a method thereof. An object is to provide an electromagnetic induction heating cooker having such a rice cooking mode.

[0009]

A first configuration of a rice cooking control method using an electromagnetic induction heating cooker according to the present invention is such that an electromagnetic induction heating coil and a temperature sensor are provided below a top plate on which a pan is placed. A rice cooking control method for automatically performing rice cooking using an electromagnetic induction heating cooker provided with a control unit that controls the output of the electromagnetic induction heating coil based on the temperature detected by the temperature sensor, After the start of heating by the electromagnetic induction heating coil, the time when the rate of change of the temperature detected by the temperature sensor decreases to a predetermined value or less is determined as the boiling point, and the temperature detected by the temperature sensor at that time is stored as the boiling point temperature, and The temperature obtained by adding a predetermined addition temperature to the boiling point temperature is defined as the cooking determination temperature, and when the temperature detected by the temperature sensor exceeds the cooking determination temperature, the step of transitioning to the mulling process is performed. Possible to execute processing including the control unit and said.

According to such a construction, even in the electromagnetic induction heating cooker in which the temperature of the pan is indirectly measured by the temperature sensor provided on the lower side of the top plate, the cooking can be accurately detected. Therefore, it is possible to shift from the cooking process to the mulling process at an appropriate time. As a result, automatic rice cooking is properly performed.

Preferably, the processing executed by the control unit is
A step of determining the amount of cooked rice based on the time from the start of heating by the electromagnetic induction heating coil to the time of boiling, or a rate of change in the temperature detected by the temperature sensor, and a step of changing the added temperature according to the determined amount of cooked rice It also includes and. By doing so, the appropriate cooked determination temperature is automatically set according to the amount of cooked rice (the amount of rice), so that appropriate automatic cooked rice is executed even if the amount of cooked rice is different.

A second configuration of the rice cooking control method using the electromagnetic induction heating cooker according to the present invention is such that an electromagnetic induction heating coil and a temperature sensor are arranged below the top plate on which the pan is placed. A rice cooking control method for automatically cooking rice using an electromagnetic induction heating cooker equipped with a control unit that controls the output of the electromagnetic induction heating coil based on the temperature detected by a sensor. After the start, the step of determining the time when the rate of change of the temperature detected by the temperature sensor has decreased below a predetermined value as the boiling point, and the step of transitioning to the muddling step when the predetermined cooking time has elapsed from the boiling point, The control unit is caused to execute a process including.

With such a construction, even in the electromagnetic induction heating cooker in which the temperature of the pan is indirectly measured by the temperature sensor provided on the lower side of the top plate, the cooked food is accurately detected. Therefore, it is possible to shift from the cooking process to the mulling process at an appropriate time. As a result, automatic rice cooking is properly performed.

Preferably, the processing executed by the control unit is
The step of determining the amount of cooked rice based on the time from the start of heating by the electromagnetic induction heating coil to the time of boiling, or the rate of change in the temperature detected by the temperature sensor, and the cooking time is changed according to the determined amount of cooked rice. And steps. By doing so, an appropriate cooking time is automatically set according to the amount of cooked rice (the amount of rice), so that appropriate automatic cooked rice is executed even if the amount of cooked rice is different.

A third configuration of the rice cooking control method using the electromagnetic induction heating cooker according to the present invention is such that an electromagnetic induction heating coil and a temperature sensor are arranged below the top plate on which the pan is placed, and A rice cooking control method for automatically cooking rice using an electromagnetic induction heating cooker equipped with a control unit that controls the output of the electromagnetic induction heating coil based on the temperature detected by a sensor. After the start, the step of determining the time when the rate of change of the temperature detected by the temperature sensor falls below the first set value as the boiling point, and the rate of change of the temperature detected by the temperature sensor starts increasing again and exceeds the second set value. The control unit is caused to execute a process including a step of shifting to the purging process when a set time has elapsed from the point of time.

According to such a configuration, even in the electromagnetic induction heating cooker in which the temperature of the pan is indirectly measured by the temperature sensor provided on the lower side of the top plate, the cooking (predetermined timing ) Is accurately detected, it is possible to shift from the cooking process to the mulling process at an appropriate time. As a result, automatic rice cooking is properly performed.

The electromagnetic induction heating cooker according to the first aspect of the present invention has a top plate on which pots are placed, an electromagnetic induction heating coil disposed below the top plate, and the electromagnetic induction heating coil. An inverter circuit for driving the induction heating coil, a temperature sensor arranged in the vicinity of the electromagnetic induction heating coil, an operation panel section having a key switch and a display for setting and executing heating and cooking, a temperature sensor and operation An electromagnetic induction heating cooker equipped with a control unit that controls an inverter circuit according to a signal from the panel unit, and a means for selecting a rice cooking mode for automatically cooking rice as a heating cooking mode is provided in the operation panel unit. In the rice cooking mode, the control unit waits for the time when the rate of change of the temperature detected by the temperature sensor decreases below a predetermined value after starting heating with the electromagnetic induction heating coil. Determining that the time Teng, 炊上 up time a predetermined and executes processing including the steps of transition to step steaming when passed from boiling point.

With such a construction, even in the electromagnetic induction heating cooker in which the temperature of the pan is indirectly measured by the temperature sensor provided on the lower side of the top plate, the cooked food can be accurately detected. Therefore, it is possible to shift from the cooking process to the mulling process at an appropriate time. As a result, automatic rice cooking is properly performed.

The second structure of the electromagnetic induction heating cooker according to the present invention is such that a top plate on which pots are placed, an electromagnetic induction heating coil disposed below the top plate, and the electromagnetic induction heating coil. An inverter circuit for driving the induction heating coil, a temperature sensor arranged in the vicinity of the electromagnetic induction heating coil, an operation panel section having a key switch and a display for setting and executing heating and cooking, a temperature sensor and operation An electromagnetic induction heating cooker equipped with a control unit that controls an inverter circuit according to a signal from the panel unit, and a means for selecting a rice cooking mode for automatically cooking rice as a heating cooking mode is provided in the operation panel unit. When the control unit is in the rice cooking mode and the rate of change in the temperature detected by the temperature sensor decreases below the first set value after the heating by the electromagnetic induction heating coil is started. Is determined as the boiling point, and a step of transitioning to the mulling step when a set time elapses after the rate of change of the temperature detected by the temperature sensor starts increasing again and exceeds the second set value It is characterized by executing.

According to such a configuration, even in the electromagnetic induction heating cooker in which the temperature of the pan is indirectly measured by the temperature sensor provided on the lower side of the top plate, the cooking (predetermined timing) ) Is accurately detected, it is possible to shift from the cooking process to the mulling process at an appropriate time. As a result, automatic rice cooking is properly performed.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the appearance of an electromagnetic induction heating cooker according to an embodiment of the present invention. (A) is a plan view and (b) is a front view. Moreover, FIG. 2 is a cross-sectional view of the electromagnetic induction heating cooker in a side view. The electromagnetic induction heating cooker of the present embodiment,
This is a so-called stationary type two-mouth stove, and the position where pots are placed on the surface of the top plate 11 made of heat-resistant ceramic (glass) is indicated by two circles (pot position mark) 12. On the right side of the front surface is provided an operation panel section 14 having key switches and indicators described later, and on the left side thereof is a roaster door 15 for heating and cooking fish and meat using an electric heater.

As shown in FIG. 2, an electromagnetic induction heating coil 16 is disposed below the top plate 11 at a position corresponding to the pan position mark 12 (to correspond to the two pan position marks 12). Two electromagnetic induction heating coils 16 are arranged). In addition, a temperature sensor 17 is arranged in the center of each electromagnetic induction heating coil 16 so as to abut the lower surface of the top plate 11.

A heat shield plate 18 is provided below the electromagnetic induction heating coil 16, and two printed circuit boards 2 are provided in the space below the heat shield plate 18.
1, 22 are arranged. Each printed circuit board 2
An inverter circuit for driving the corresponding electromagnetic induction heating coil 16 and a control circuit thereof are mounted on the units 1 and 2. Heat sinks 23, 24 for the power switching elements of each inverter circuit are shown.

The two printed boards 21 and 22 are housed in the respective board boxes 19 and 20 and are arranged in two layers. A cooling fan 25 is arranged behind the printed boards 21 and 22. The wind from the cooling fan 25 receives heat from the heat sinks 23, 2 of the printed circuit boards 21, 22.
4 is mainly cooled.

FIG. 3 is a block diagram showing the circuit configuration of the electromagnetic induction heating cooker of this embodiment. In addition, in FIG.
A pot 30 for cooking rice is placed on the top plate 11,
A configuration is shown in which the temperature sensor 17 arranged so as to contact the lower surface of the top plate 11 detects the temperature of the pan 30 via the top plate 11.

The inverter circuit 31 for driving the electromagnetic induction heating coil 16 is controlled by the controller 32. The control unit 32 is composed of a microcomputer including a CPU, a memory (ROM and RAM), a clock circuit, an input / output port and the like. The control unit 32 includes a temperature sensor 1
Operation signal 33 of the operation panel unit 14 together with the output signal of 7
A signal (a set of a plurality of key switches) is input. Further, the control unit 32 controls the display device 34 (collection of a plurality of display devices) of the operation panel unit 14 and also controls the ringing of the buzzer 35 for various notifications.

The control unit 32 is an RO of a microcomputer.
According to the program stored in M, the control of the inverter circuit 31, the output signal of the temperature sensor 17, the input of the operation key 33, the display output, the buzzer sounding and the like are executed. The control unit 32 can adjust the output (thermal power) of the electromagnetic induction heating coil 16 by changing the duty factor (current ratio) of the switching element that constitutes the inverter circuit 31.

FIG. 4 is a diagram showing the configuration of the operation panel section 14. The operation panel unit 14 includes a plurality of key switches and an indicator as described above, and the details thereof are as shown in FIG. The use and operation of each key switch and display will be described below.

First, on the upper left side of the operation panel section 14, an on / off key 41 for instructing start and stop of the inverter circuit 31 for driving the electromagnetic induction heating coil 16 of the left stove.
And an indicator (LED) 4 that lights up in its ON state
1a and an increase / decrease key 42 for adjusting heating power are provided.

On the lower side thereof, a selection key 4 for selecting cooking of fish or meat by roaster using an electric heater.
5. A selection key 46 for selecting heat retention or thawing, an increase / decrease key 47 for setting a temperature for heating or heat retention or a weight setting for thawing, and an on / off key 48 for an electric heater are provided. The on / off key 48 has an indicator (LED) 48a that lights up in the on state. Selection key 45,
Indicators (LEDs) 49 and 50 for guiding the next operation are provided between the 46 and the increase / decrease key 47 and between the increase / decrease key 47 and the on / off key 48.

An inverter circuit 31 for driving the electromagnetic induction heating coil 16 of the right stove is provided on the right side of the operation panel section 14.
There are provided an on / off key 43 for instructing start and stop, an indicator (LED) 43a that lights up in the on state, and an increase / decrease key 44 for adjusting heating power.
The right cooking stove can select a fried food mode or an automatic cooking mode as a heating cooking mode, and is provided with a fried food mode selection key 51 and an automatic cooking mode selection key 52.

Further, a temperature setting key (increase / decrease key) 53 for setting the fried food temperature when the fried food mode is selected is provided. When the automatic cooking mode is selected, the increase / decrease key 53 is also used as a strengthening or weakening setting key. On / off key 5 for instructing start and stop of the inverter circuit 31 when the fried food mode or the automatic cooking mode is selected
4 is separately provided and is provided with an indicator (LED) 54a that lights up in the ON state. Further, between the deep-fried food mode selection key 51 and the automatic cooking mode selection key 52 and the increase / decrease key 53, and between the increase / decrease key 53 and the on / off key 5
4 and an indicator (LE that guides the next operation.
D) 55 and 56 are provided.

A display unit 59 is provided at the center of the operation panel unit 14.
Is provided, and a timer selection key 57 and a setting key (increase / decrease key) 58 are provided below it. When it is desired to automatically stop the inverter circuit that drives the electromagnetic induction heating coil after a set time, the timer selection key 57 is pressed to select the left or right stove, and the increase / decrease key 58 is used to set the off timer time.

The display unit 59 is a display device (7
In addition to a segment 3-digit LED) 61 and a display 62 for displaying the weight, a plurality of indicators 63 are lit in each cooking mode. In the automatic cooking mode, one of the triangular indicators arranged on the upper side of each print display of "rice cooked", "warm", "steamed" and "boiled" lights up. When the automatic cooking mode is set, each time the automatic cooking mode selection key 52 is pressed, each indicator lights in turn, and any one of the automatic cooking is selected. Therefore, the automatic cooking mode selection key 52 and the display unit 59 correspond to a means for selecting the rice cooking mode.

Above the triangular indicator in the automatic cooking mode, there are provided a "fried food" indicator that lights up in the fried food mode and a timer indicator that lights up when the off timer is set. Each time the timer selection key 57 is pressed when the off-timer is set, the “left” or “right” indicator is alternately turned on and the left or right stove is selected.

The indicator 62 for displaying the weight is used to set the weight of the target food with the increase / decrease key 47 when the roasting by the roaster is selected with the selection key 46. The weight (grams) of the food to be thawed is displayed as a maximum of 3 digits.

The display 61 capable of displaying time is used to display the remaining time until the completion of cooking, etc., depending on the contents of automatic cooking. The "after" indicator lights up and the remaining time (minutes) is displayed with a maximum of 3 digits. For example, in the rice cooking mode during automatic cooking, the time (minutes) until the end (cooking of rice) is displayed as a two-digit or one-digit numerical value with the shift to the Murashi process.

Next, the rice cooking control executed by the controller 32 when the rice cooking mode in the automatic cooking is selected and the heating cooking is started will be described.

FIG. 5 is a flowchart showing a first example of rice cooking control according to the embodiment of the present invention. In addition, FIG.
It is a graph which shows the example of the temperature change of each part for demonstrating the 1st example of rice cooking control. In FIG. 6, a solid curve C1 indicates a change in the temperature of the bottom of the pot 30 (hereinafter referred to as a pan bottom temperature), and a short dashed curve C2 indicates a change in the temperature detected by the temperature sensor 17. Further, as a reference, a change in water temperature at a position approximately 1 cm from the bottom of the pot 30 is shown by a long dashed curve C3, and a change in controlled thermal power (output of the electromagnetic induction heating coil 16) is indicated by a two-dot chain line L1. It is shown.

In the flow chart of FIG. 5, when rice cooking is started, the electromagnetic induction heating coil 16 is driven with high thermal power (for example, 80% output) (step # 101). Pot 3
As 0 is heated, the pot bottom temperature C1, the water temperature C3, and the temperature C2 detected by the temperature sensor 17 increase. Among these three temperatures, the temperature detected by the actual electromagnetic induction heating cooker is only the temperature detected by the temperature sensor 17.

When a predetermined time (for example, 3 minutes) has elapsed from the start of heating (Yes in step # 102), the detected temperature T (current temperature) of the temperature sensor 17 is checked and stored (step # 103). Then, the temperature change rate ΔT /
It is checked whether or not Δt has decreased below a predetermined value α (for example, 0.1 ° C./sec) (step # 104).

As can be seen from the graph of FIG. 6, when the pot bottom temperature C1 and the water temperature C3 reach about 100 ° C., boiling of water starts, and the temperature change rate ΔT / Δt eventually decreases. Therefore, the time when the temperature change rate ΔT / Δt decreases below the predetermined value α is determined as the boiling time, and the temperature detected by the temperature sensor 17 at that time is stored as the boiling time temperature T1 (step # 105).

In the actual control, the temperature detected by the temperature sensor 17 is stored, for example, every 10 seconds, and when the difference between the current temperature and the stored temperature (previous detection temperature) becomes 0.1 ° C. or less, the boiling point is reached. By performing the processing for determining, it is possible to simplify the check of the temperature change rate ΔT / Δt.

In the following step # 106, the amount of cooked rice is determined. In other words, by utilizing the fact that the larger the amount of cooked rice is, the longer the time from the start of cooking rice to the boiling point is, the amount of cooked rice is classified into large, medium, and small levels according to the time from the start of cooking rice to the boiling point. Depending on the determination result, the detection temperature (heating determination temperature) for making the cooking determination is changed.

That is, the cooking determination temperature T2 is obtained by adding the additional temperature Ta to the boiling point temperature T1 (T2 = T1 + Ta), and this additional temperature Ta is used for the large, medium and small amount of cooked rice. Accordingly, it is set to 15 ° C., 10 ° C., and 5 ° C., respectively (steps # 107 to # 111). Therefore, the larger the amount of cooked rice, the higher the cooked determination temperature.

Thereafter, the heating power is changed from strong to weak (step # 112). As a result, the boiling process shifts to the cooking process. Then, the current temperature is detected (step # 11
3) When the current temperature exceeds the above cooking temperature (Yes in step # 114), the cooking process is terminated and the unevenness process is performed. In the stripping step, as shown in FIG. 6, the heating power (electromagnetic induction heating coil 16) is set to zero and left for a predetermined time. Alternatively, heat with a very small amount of heat. During this time, as described above, the remaining time until the end of the Murashi process (that is, the completion of cooking rice) is displayed on the display 61 of the operation panel unit 14 as a subtraction timer.

The above numerical value of the addition temperature Ta is merely an example, and can be changed appropriately. In addition, in the graph of FIG. 6 based on the actual measurement value of the experiment, the added temperature Ta is 2
It is shown at about 8 ° C.

Further, from step # 106 to step # 1
The process of 11 is not essential, and may be a constant addition temperature regardless of the amount of cooked rice. Alternatively, the amount of cooked rice (large,
(Medium and small) may be input and stored in advance. In this case, instead of the cooked rice amount determination processing performed in step # 106, the stored cooked rice amount classification is read and an appropriate added temperature is set. In the above example, the amount of cooked rice is divided into three stages, but it may be divided into two stages or four or more stages.

FIG. 7 is a flow chart showing a second example of rice cooking control according to the embodiment of the present invention. In addition, FIG.
It is a graph which shows the example of the temperature change of each part for demonstrating the 2nd example of rice cooking control. In FIG. 8, a solid curve C1 indicates a change in the temperature of the bottom of the pot 30 (hereinafter referred to as a pan bottom temperature), and a short dashed curve C2 indicates a change in the temperature detected by the temperature sensor 17. Further, as a reference, a change in water temperature at a position approximately 1 cm from the bottom of the pot 30 is shown by a long dashed curve C3, and a change in controlled thermal power (output of the electromagnetic induction heating coil 16) is indicated by a two-dot chain line L1. It is shown.

In the flow chart of FIG. 7, when rice cooking is started, the electromagnetic induction heating coil 16 is driven with high thermal power (for example, 80% output) (step # 201). Pot 3
As 0 is heated, the pot bottom temperature C1, the water temperature C3, and the temperature C2 detected by the temperature sensor 17 increase. Among these three temperatures, the temperature detected by the actual electromagnetic induction heating cooker is only the temperature detected by the temperature sensor 17.

When a predetermined time (for example, 3 minutes) has elapsed from the start of heating (Yes in step # 202), the detected temperature T (current temperature) of the temperature sensor 17 is checked and stored (step # 203). Then, the temperature change rate ΔT /
It is checked whether or not Δt has decreased below a predetermined value α (for example, 0.1 ° C./sec) (step # 204).

As can be seen from the graph of FIG. 8, when the pot bottom temperature C1 and the water temperature C3 reach about 100 ° C., boiling of water starts, and the temperature change rate ΔT / Δt eventually decreases. Therefore, it is determined that the time when the temperature change rate ΔT / Δt decreases to the predetermined value α or less is the boiling time (Yes in step # 204),
Go to step # 205.

In the actual control, the temperature detected by the temperature sensor 17 is stored, for example, every 10 seconds, and if the difference between the current temperature and the stored temperature (previous detection temperature) becomes 0.1 ° C. or less, the boiling point is reached. By performing the processing for determining, it is possible to simplify the check of the temperature change rate ΔT / Δt.

At step # 205, the amount of cooked rice is determined. In other words, by utilizing the fact that the larger the amount of cooked rice is, the longer the time from the start of cooking rice to the boiling point is, the amount of cooked rice is classified into large, medium, and small levels according to the time from the start of cooking rice to the boiling point. The cooking time is changed according to the determination result.

That is, according to the amount of cooked rice, large, medium and small,
Three stages of cooking time of 15 minutes, 12 minutes, and 10 minutes are set (steps # 206 to # 210). As a matter of course,
The larger the amount of rice cooked, the longer the cooking time is set.

Thereafter, the heating power is changed from strong to weak (step # 211). As a result, the boiling process shifts to the cooking process. Then, when the above-mentioned cooking time has elapsed (Yes in step # 212), the cooking process is terminated and the process shifts to the purging process. In the purging process, as shown in FIG. 8, the heating power (electromagnetic induction heating coil 16) is set to zero and left for a predetermined time. Alternatively, heat with a very small amount of heat. During this time, as described above, the remaining time until the end of the Murashi process (that is, the completion of cooking rice) is displayed on the display 61 of the operation panel unit 14 as a subtraction timer.

The above cooking time is merely an example, and can be changed as appropriate. Further, in the graph of FIG. 8 based on the actual measurement values obtained by the experiment, the boiling process time is about 9 minutes, the cooking time is about 13 minutes, and the mulling process time is about 5 minutes. .

Also, from step # 205 to step # 2
The process of 10 is not essential, and the cooking time may be constant regardless of the amount of cooked rice. Alternatively, the classification of the amount of cooked rice (large, medium, small) may be input and stored in advance. In this case, instead of the processing for determining the amount of cooked rice performed in step # 205, the stored classification of the amount of cooked rice is read and an appropriate cooking time is set.
In the above example, the amount of cooked rice is divided into three levels,
It may be divided into two stages or may be divided into four or more stages.

FIG. 9 is a flowchart showing a third example of rice cooking control according to the embodiment of the present invention. In addition, FIG.
[Fig. 6] is a graph showing an example of temperature change of each part for explaining a third example of rice cooking control. In FIG. 10, a solid curve C1 indicates a change in the temperature of the bottom of the pot 30 (hereinafter referred to as a pan bottom temperature), and a short dashed curve C2 indicates a change in the temperature detected by the temperature sensor 17. Also, as a reference, pot 30
The change in the water temperature at a position approximately 1 cm from the bottom of the is indicated by a long dashed curve C3, and the controlled thermal power (electromagnetic induction heating coil 1
The change in the output (6) is indicated by a two-dot chain line L1.

In the flow chart of FIG. 9, when rice cooking is started, the electromagnetic induction heating coil 16 is driven with high thermal power (for example, 80% output) (step # 301). Pot 3
As 0 is heated, the pot bottom temperature C1, the water temperature C3, and the temperature C2 detected by the temperature sensor 17 increase. Among these three temperatures, the temperature detected by the actual electromagnetic induction heating cooker is only the temperature detected by the temperature sensor 17.

First set time (for example, 3 minutes) from the start of heating
When has elapsed (Yes in step # 302), the detected temperature T (current temperature) of the temperature sensor 17 is checked and stored (step # 303). And the temperature change rate Δ
It is checked whether or not T / Δt has decreased below the first set value α (for example, 0.1 ° C./sec) (step # 30).
4).

As can be seen from the graph of FIG. 10, when the pot bottom temperature C1 and the water temperature C3 reach about 100 ° C., boiling of water starts, and the temperature change rate ΔT / Δt eventually decreases. Therefore, the time point when the temperature change rate ΔT / Δt decreases below the predetermined value α is determined as the boiling time point (Yes in step # 304).
s), and proceeds to step # 305.

In the actual control, for example, the temperature detected by the temperature sensor 17 is stored every 10 seconds, and if the difference between the current temperature and the stored temperature (previous detection temperature) becomes 0.1 ° C. or less, the boiling point is reached. By performing the processing for determining, it is possible to simplify the check of the temperature change rate ΔT / Δt.

In step # 305, the heat power is changed from strong to weak. As a result, the boiling process shifts to the cooking process. In step # 306, a predetermined time has elapsed (this step is not essential), and in step # 307, the temperature T (current temperature) detected by the temperature sensor 17 is checked and stored again. In subsequent step # 308, the temperature change rate Δ
It is checked whether T / Δt exceeds the second set value β.

That is, as shown by the curve C2 in FIG. 10, the temperature change rate ΔT / Δt starts to increase again after a short time after starting the cooking process. This is a phenomenon caused by the boiling water disappearing and the boiling phenomenon disappearing, whereby the pot bottom temperature rises rapidly as shown by the curve C1.

The second set value β is the above-mentioned first set value α.
The value may be the same as (for example, 0.1 ° C./second), or a different value may be set. Further, the temperature change rate ΔT / Δt is the second
Also regarding the check as to whether or not the set value β is exceeded, for example, the detected temperature of the temperature sensor 17 is stored every 10 seconds, and the difference between the present temperature and the stored temperature (previously detected temperature) is 0.1 ° C.
It may be simplified so as to determine whether or not is exceeded.

In step # 308, the temperature change rate ΔT / Δt
Is detected to exceed the second set value β, the process proceeds to step # 309 to restart the time measurement, and the second set time t2
When (see FIG. 10) has elapsed (Yes in step # 310), the cooking process is terminated and the process shifts to the muffler process.
In the stripping step, as shown in FIG. 10, the heating power (electromagnetic induction heating coil 16) is set to zero and left for a predetermined time. Alternatively, heat with a very small amount of heat. During this time, as described above, the remaining time until the end of the Murashi process (that is, the completion of cooking rice) is displayed on the display 61 of the operation panel unit 14 as a subtraction timer.

Next, the control for preventing spillage will be described. In a dedicated rice cooker, a lid equipped with a pressure regulating valve is fixed to the main body in a sealed structure to prevent spillage during boiling. However, when rice is cooked using a general-purpose pot like the configuration shown in FIG. 3, spillage is likely to occur at the time of boiling. In normal rice cooking control, heating is performed at the maximum output (or strong output) until boiling is detected. 32 executes.

FIG. 11 is a flowchart of the spillover prevention control executed by the control unit 32. When rice cooking is started, the electromagnetic induction heating coil 16 is driven with an output of 90% (step # 401). After a predetermined time (step #
(Yes in 402), the temperature detected by the temperature sensor 17 (current temperature) is checked.

When it is determined in the next step # 404 that the current temperature is the temperature immediately before boiling, step # 40
The output of the electromagnetic induction heating coil 16 is lowered by the processing of 5 and thereafter. First, the amount of cooked rice is determined in step # 405. That is, as described above, the amount of cooked rice is discriminated into three levels of large, medium, and small according to the time from the start of cooking rice. According to the determination result, the output of the electromagnetic induction heating coil 16 (output after reduction) is set in three stages of 80%, 75%, and 70% (steps # 406 to # 410). The larger the amount of cooked rice, the smaller the decrease in output (the output after decrease decreases).

The output of the electromagnetic induction heating coil 16 is changed to the set output after the decrease (step # 411), and the boiling detection is awaited. The method for detecting boiling is as described above. When boiling is detected (Yes in step # 412)
s), shift to the cooking process. Since the subsequent processing has already been described, the repetitive description will be omitted. The value (%) of the output of the electromagnetic induction heating coil 16 is merely an example and can be changed as appropriate.

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and modifications.
It can be implemented in various forms. For example, in the electromagnetic induction heating cooker according to the above-described embodiment, as described using the operation panel unit 14 shown in FIG. 4, only the right stove corresponds to the automatic cooking mode including the rice cooking mode. However, the present invention is not limited to such a configuration, and the rice cooking mode (automatic cooking mode) may be executed on either the left or right stove. In this case, it is preferable to provide an interlock that prevents the rice cooking mode from being selected on the other stove while the rice cooking mode is being executed on one stove.

When the rice cooking mode is being executed on one stove and the other cooking is being executed on the other stove, if the total power consumption may exceed the rated power, the rice cooking mode is being executed. It is desirable to give priority to the electromagnetic induction heating coil 16 and to control so that the drive power of the other electromagnetic induction heating coil 16 is limited.

Although the control example of increasing or decreasing the cooking time according to the amount of cooked rice has been described, the cooking time is adjusted according to the correction of extending the cooking time when power shortage occurs or the characteristics of the pan. You may correct it.

Further, the present invention is not limited to the two-burner stove, but can be applied to one or three or more types of electromagnetic induction heating cookers.

[0077]

As described above, according to the rice cooking control method using the electromagnetic induction heating cooker and the electromagnetic induction heating cooker having the rice cooking mode of the present invention, the rice is provided below the top plate. Even with an electromagnetic induction heating cooker in which the temperature of the pot is indirectly measured by a temperature sensor, it is possible to accurately perform boiling detection and determination of cooking based on it.
It is possible to shift from the cooking process to the Murashi process at an appropriate time. As a result, automatic rice cooking is properly performed, and delicious rice can be cooked.

[Brief description of drawings]

FIG. 1 is an external view of an electromagnetic induction heating cooker according to an embodiment of the present invention, (a) is a plan view and (b) is a front view.

FIG. 2 is a side sectional view of the electromagnetic induction heating cooker according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a circuit configuration of the electromagnetic induction heating cooker according to the embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an operation panel unit of the electromagnetic induction heating cooker according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a first example of rice cooking control according to the embodiment of the present invention.

FIG. 6 is a graph showing an example of temperature change of each part for explaining the first example of rice cooking control.

FIG. 7 is a flowchart showing a second example of rice cooking control according to the embodiment of the present invention.

FIG. 8 is a graph showing an example of temperature change of each part for explaining a second example of rice cooking control.

FIG. 9 is a flowchart showing a third example of rice cooking control according to the embodiment of the present invention.

FIG. 10 is a graph showing an example of temperature change of each part for explaining a third example of rice cooking control.

FIG. 11 is a flowchart of a spillover prevention control executed by a control unit.

[Explanation of symbols]

11 Top Plate 14 Operation Panel 16 Electromagnetic Induction Heating Coil 17 Temperature Sensor 30 Pan 31 Inverter Circuit 32 Controller 52 Automatic Cooking Mode Selection Key (Means to Select Rice Cooking Mode) 59 Display (Means to Select Rice Cooking Mode)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K051 AA08 AB04 AC33 AD12 BD04                       CD06 CD07                 4B055 AA03 AA09 CD02 CD46 DB14                       GA04 GA08 GA10 GB03 GB06                       GB08 GB12 GB18 GC01 GC14                       GC21 GD02 GD05 GD06

Claims (8)

[Claims] 1. A control unit in which an electromagnetic induction heating coil and a temperature sensor are disposed below a top plate on which a pan is placed, and which controls the output of the electromagnetic induction heating coil based on the temperature detected by the temperature sensor. A rice cooking control method for automatically cooking rice using an electromagnetic induction heating cooker, comprising: after starting heating by the electromagnetic induction heating coil, a rate of change in temperature detected by the temperature sensor is equal to or lower than a predetermined value. The boiling point is determined as the boiling point, and the temperature obtained by adding a predetermined additional temperature to the boiling point temperature is stored as the boiling point temperature. The control unit is caused to perform a process including a step of transitioning to a murmuring process when the temperature detected by the temperature sensor exceeds the cooking determination temperature. Cooking control method using an induction heating cooker. 2. The amount of cooked rice is determined based on the time from the start of heating by the electromagnetic induction heating coil to the time of boiling, or the rate of change in the temperature detected by the temperature sensor. The method of controlling rice cooking using an electromagnetic induction heating cooker according to claim 1, further comprising: a step of changing the added temperature according to the determined amount of cooked rice. 3. An electromagnetic induction heating coil and a temperature sensor are arranged below the top plate on which the pan is placed, and a control unit for controlling the output of the electromagnetic induction heating coil based on the temperature detected by the temperature sensor. A rice cooking control method for automatically cooking rice using an electromagnetic induction heating cooker, comprising: after starting heating by the electromagnetic induction heating coil, a rate of change in temperature detected by the temperature sensor is equal to or lower than a predetermined value. It is characterized in that the control unit is caused to execute a process including a step of determining the time point of decrease as a boiling time point, and a step of transitioning to a muddling step when a predetermined cooking time elapses from the boiling time point. A rice cooking control method using an electromagnetic induction heating cooker. 4. The amount of cooked rice is determined based on the time from the start of heating by the electromagnetic induction heating coil to the boiling point, or the rate of change in the temperature detected by the temperature sensor. 4. The rice cooking control method using the electromagnetic induction heating cooker according to claim 3, further comprising: a step of changing the cooking time according to the determined amount of cooked rice. 5. An electromagnetic induction heating coil and a temperature sensor are disposed below a top plate on which a pan is placed, and a control unit which controls the output of the electromagnetic induction heating coil based on the temperature detected by the temperature sensor. A rice cooking control method for automatically cooking rice using an electromagnetic induction heating cooker, comprising: a rate of change of a temperature detected by the temperature sensor after starting heating by the electromagnetic induction heating coil; The step of determining the time point when the temperature decreases below is the time point of boiling, and the rate of change in the temperature detected by the temperature sensor starts increasing again and exceeds the second set value. A method of controlling rice cooking using an electromagnetic induction heating cooker, comprising: 6. A top plate on which pots are placed, an electromagnetic induction heating coil arranged below the top plate, an inverter circuit for driving the electromagnetic induction heating coil, and the electromagnetic induction heating coil. A temperature sensor arranged in the vicinity of, an operation panel unit having a key switch and a display for setting and executing heating and cooking, and controlling the inverter circuit in accordance with signals from the temperature sensor and the operation panel unit. An electromagnetic induction heating cooker with a control unit to perform, the operation panel unit is provided with a means for selecting a rice cooking mode for automatically cooking rice as a heating and cooking mode, the control unit in the rice cooking mode, After starting heating by the electromagnetic induction heating coil, the time when the rate of change of the temperature detected by the temperature sensor is reduced to a predetermined value or less is determined as the boiling time, And a step of storing the temperature detected by the temperature sensor as a boiling point temperature, a temperature obtained by adding a predetermined addition temperature to the boiling point temperature is a cooking determination temperature, and the temperature detected by the temperature sensor is An electromagnetic induction heating cooker characterized by performing a process including a step of transitioning to a murmuring process when a cooking determination temperature is exceeded. 7. A top plate on which pots are placed, an electromagnetic induction heating coil arranged below the top plate, an inverter circuit for driving the electromagnetic induction heating coil, and the electromagnetic induction heating coil. A temperature sensor arranged in the vicinity of, an operation panel unit having a key switch and a display for setting and executing heating and cooking, and controlling the inverter circuit in accordance with signals from the temperature sensor and the operation panel unit. An electromagnetic induction heating cooker with a control unit to perform, the operation panel unit is provided with a means for selecting a rice cooking mode for automatically cooking rice as a heating and cooking mode, the control unit in the rice cooking mode, After the heating by the electromagnetic induction heating coil is started, the time when the rate of change of the temperature detected by the temperature sensor decreases to a predetermined value or less is determined as the boiling time. Step a, an electromagnetic induction cooker, characterized in that 炊上 up time a predetermined executes processing including the steps of transition to step steaming when has elapsed since the boiling point. 8. A top plate on which pots are placed, an electromagnetic induction heating coil arranged below the top plate, an inverter circuit for driving the electromagnetic induction heating coil, and the electromagnetic induction heating coil. A temperature sensor arranged in the vicinity of, an operation panel unit having a key switch and a display for setting and executing heating and cooking, and controlling the inverter circuit in accordance with signals from the temperature sensor and the operation panel unit. An electromagnetic induction heating cooker with a control unit to perform, the operation panel unit is provided with a means for selecting a rice cooking mode for automatically cooking rice as a heating and cooking mode, the control unit in the rice cooking mode, After the start of heating by the electromagnetic induction heating coil, the time when the rate of change of the temperature detected by the temperature sensor decreases below the first set value is determined as the boiling time. And a step of transitioning to a muting process when a set time elapses from the time when the rate of change of the temperature detected by the temperature sensor starts increasing again and exceeds the second set value. An electromagnetic induction heating cooker characterized by.