JP3028347B2 - Electromagnetic cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic cooker having a temperature control function.

[0002]

2. Description of the Related Art A conventional electromagnetic cooker of this type will be described with reference to FIGS.

FIG. 7 is a block diagram of a conventional electromagnetic cooker,
FIG. 8 is a diagram showing the shape of the bottom of the pot, and FIGS. 9 and 10 are temperature control characteristic diagrams thereof.

In FIG. 7, a conventional electromagnetic cooker includes an induction heating coil 3 for heating the cooking vessel 1 on a lower surface of a top plate 2 made of a ceramic plate on which the cooking vessel 1 is placed.
The temperature of the cooking vessel 1 is indirectly detected by the temperature detecting element 5 of the heat collecting plate 4 made of an aluminum plate attached to the lower surface of the top plate 2, and the coil is detected. The current flowing through the induction heating coil 3 was controlled by the current control device 6.

To detect the temperature, the comparator 7 compares the voltage signal of the temperature set by the setting variable resistor 8 with the voltage signal of the temperature detected by the voltage division of the temperature detecting element 5 and the resistor 9. If the detected temperature is higher than the set temperature, the coil current control device 6 stops and turns on the induction heating coil 3 so that the heating of the cooking vessel 1 is stopped. To control the temperature of the temperature detecting element 5,
Indirectly, the temperature of the cooking vessel 1 is kept at the set temperature.

The heat collecting plate 4 exhibits a heat collecting effect on the flat pot 1a having a flat bottom as shown in FIG. 8 and also on the bottom concave pot 1b, and exhibits good temperature detection characteristics.

[0007]

However, since the heat collecting plate 4 is made of an aluminum plate,
Although a wide range of temperatures can be detected by the heat collection effect, the temperature is inaccurate due to self-heating under the influence of the induction heating magnetic field, and there has been a problem that highly accurate temperature control cannot be performed.

Further, when the heat collecting plate 4 is removed and the back surface temperature of the top plate 2 is directly detected, it takes time to transmit the temperature from the bottom of the cooking vessel 1 through the top plate 2 and the time of the heat transfer during the feedback control closed loop. Since the delay occurs, hunting as shown in FIG. 10 occurs, causing a problem that stable control cannot be obtained. Although stable control can be performed artificially based on intuition, experience, and the like, it is difficult to formulate the relationship between the detected temperature and the heating output.

The present invention has been made to solve the above-mentioned problems, and provides an electromagnetic cooker capable of performing temperature control with high accuracy, good stability, and good responsiveness.

[0010]

In order to solve the above-mentioned problems, the present invention provides a first temperature sensing element mounted on the lower surface of a top plate and at the center of an induction heating coil, and a differential of the output of the temperature sensing element. A differentiating means for detecting a value, a second temperature detecting element mounted on a heat collecting plate mounted on a lower surface of the top plate, respective detected temperatures of the first and second temperature detecting elements, an output of the differentiating means. And a fuzzy inference device that determines the output of the induction heating coil by fuzzy inference based on the input value of the set temperature, and a coil current that controls the current flowing through the induction heating coil and controls the output of the coil by the output of the fuzzy inference device. A control means is provided.

In addition, a first differentiating means for detecting a differential value of the output of the first temperature detecting element and a second differentiating means for detecting a differential value of the output of the second temperature detecting element are newly provided. A fuzzy inference device for determining the output of the induction heating coil by fuzzy inference based on the detected temperature of the first temperature sensing element, the output of the first differentiating means, the input value of the set temperature, and the output of the second differentiating means; Coil current control means for controlling the current supplied to the induction heating coil by the output of the inference device to control the output of the coil is provided.

Also, an output power detecting means for detecting the output power of the induction heating coil is provided in place of the second temperature detecting element, and the detected temperature of the first temperature detecting element, the output of the differentiating means, the output power and the set temperature are provided. A fuzzy inference device that determines the output of the induction heating coil by fuzzy inference based on the input value of the fuzzy inference device, and a coil current control unit that controls the current supplied to the induction heating coil by the output of the fuzzy inference device to control the output of the coil. It is an electromagnetic cooker provided.

In addition to the output power detecting means provided in place of the second temperature detecting element, an output power differentiating means for detecting a differential value of the power is further provided. The output of the fuzzy inference device that determines the output of the induction heating coil by fuzzy inference based on the differential value of the output power and the input value of the set temperature, and controls the conduction current of the induction heating coil by the output of the fuzzy inference device. A coil current control means for controlling the output of the coil is provided.

[0014]

According to the above configuration, the fuzzy inference device has know-how in setting the output of the heating coil according to the temperature of the temperature detecting element, so that the optimal heating output is set, and Since control according to characteristics is performed,
The stability at the time of control is increased, and highly accurate temperature control can be obtained.

In addition, by adding the temperature change of the first temperature detecting element to the input for determining the output of the heating coil, the stability at the time of control for the deformed pan bottom shape is increased, and the temperature control with high accuracy and high responsiveness is achieved. Is obtained.

Also, by adding the temperature change of the second temperature detecting element by the heat collecting plate to the input for determining the output of the heating coil, temperature control with high accuracy and high responsiveness can be obtained even in a pot whose bottom is deformed.

Since the output power detecting means detects the output of the heating coil, when the detected temperature is low in spite of the high output, or when the detected temperature change has a negative slope, the load consumption is reduced. It can be determined that the amount of heat is large, the output is determined to be higher, and the temperature control performance is further improved.

Further, since the output power differentiating means detects a change in the output of the heating coil, if the detected temperature is low despite the high output, or if the gradient of the detected temperature change is similarly negative. Thus, it can be determined that the amount of heat consumed by the load has changed greatly, and the output is determined to be higher to further improve the temperature control performance.

[0019]

Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram of an electromagnetic cooker according to a first embodiment of the present invention, and FIG. 2 is a state diagram showing an inference operation of a fuzzy inference unit of the electromagnetic cooker according to the present invention.

In FIG. 1, an electromagnetic cooker according to the present invention is provided with a top plate 2 made of a ceramic plate on which a cooking container 1 is placed, and a cooking plate 1 provided below the top plate 2 by an induction magnetic field generated by a high-frequency current. An induction heating coil 3 for generating heat, a first temperature detecting element 10 mounted at the center of the lower surface of the top plate 2, and a differential circuit 11 for the detected temperature.
A second temperature detecting element 12 attached to the heat collecting plate 4 fixed to the lower surface of the top plate 2, a setting input device 13 for setting a cooking temperature, and a differentiating circuit 11 of the first temperature detecting element 10. And output value of second temperature detecting element 12 and setting input device
A fuzzy inference unit 14 that determines the output value of the induction heating coil 3 from the set value of 13 and a coil current control device 6 that receives the output and controls a high-frequency current supplied to the induction heating coil 3 did.

The coil current control device 6 includes a high-frequency inverter circuit 6a for outputting a high-frequency current to the induction heating coil 3, and a high-frequency inverter for controlling the oscillation of the high-frequency inverter circuit 6a to control the high-frequency output current. It comprises an output control circuit 6b.

Further, the fuzzy inference unit 14 includes a temperature membership function storage circuit 14a, and a temperature suitability calculation circuit 14 connected to the circuit 14a and the first temperature detecting element 10.
b, a slope membership function storage circuit 14c for inferring the degree of temperature change, and a slope matching degree calculation circuit connected to this circuit 14c and the differentiating circuit 11 for inferring the degree of change in the temperature of the tabletop 2. 14d, a heat collecting plate temperature membership function storage circuit 14e, a heat collecting plate temperature suitability calculating circuit 14f connected to this circuit 14e and the second temperature detecting element 12, a temperature of the top plate, its inclination and its collecting temperature. An output membership function storage circuit 14g for inferring an optimum output from the respective degrees of conformity of the hot plate temperature; this circuit 14g, the above-mentioned temperature, slope and heat collecting plate temperature conformity calculating circuits 14b, 14d and 14f; An output suitability calculating circuit 14h for inferring an optimum output is connected to the setting input device 13.

The operation of the electromagnetic cooker configured as described above will be described. Since the first temperature detecting element 10 is directly mounted on the top plate 2 made of a ceramic plate, the magnetic flux generated by the induction heating coil 3 is not affected by self-heating, so that the bottom shape of the cooking vessel 1 is flat. If so, cooking container 1
The temperature can be detected accurately and with high accuracy, because it is easy to receive the heat from the device.

However, in the case of fried food with a fluctuating temperature,
Since the heat of the cooking vessel 1 is transmitted to the first temperature detecting element 10 via the top plate 2, the detected temperature is delayed by a transmission time, and control is performed based on the delayed temperature information, so that hunting is likely to occur. In order to prevent this hunting and perform more accurate temperature control, the fuzzy inference unit 14 uses a general know-how to determine an inference rule that provides an optimum heating coil output for the temperature detected by the first temperature detection element 10. -Represented by fuzzy rules based on how.

The setting input device 13 sets the set temperature to 160 ° C.
The switch can be selected discretely such as ℃, 200 ℃, etc. The temperature membership function storage circuit 14a has a fitness degree estimation rule as shown in the uppermost diagram of FIG. 2 for each set temperature in order to estimate a set value of an optimum output suitable for each set temperature. I have. The temperature matching degree calculation circuit 14b determines whether the current temperature state is high or low based on a rule stored in the temperature membership function storage circuit 14a according to the input temperature of the first temperature detecting element 10 and the set temperature. Infer whether or not. Similarly, the inclination membership function storage circuit 14c
Is used to estimate the optimal output setting suitable for each set temperature.
A fitness estimation rule as shown in the middle part of FIG. 2 is provided for each set temperature. The slope matching degree calculation circuit 14d, based on the rules stored in the slope membership function storage circuit 14c by the input from the differentiating circuit 11 and the setting input device 13,
Infer whether the current temperature change is rising, falling, or no change. Similarly, the heat collecting plate temperature membership function storage circuit 14e uses the fitness estimation rule as shown in the lower part of FIG. 2 for each set temperature in order to estimate the optimum output set value suitable for each set temperature. Have. Based on the rule stored in the heat collecting plate temperature membership function storage circuit 14e according to the detected temperature of the second temperature detecting element 12 and the set temperature, the heat collecting plate temperature conformity calculation circuit 14f determines whether the current temperature state is high. , Low or normal. The output membership function storage circuit 14g is provided with a table 1 and a table for setting the optimum output by combining the inference results of the fitness degree calculation circuits 14b, 14d, and 14f for the temperature, the slope, and the heat collecting plate temperature. According to the rule shown in FIG. 2, a more optimal output of the induction heating coil is inferred by the output adaptability calculating circuit 14h.

[0027]

[Table 1]

[0028]

[Table 2]

The above operation is repeated, and an output inferred and determined based on a fuzzy rule based on general know-how, that is, a stable hunting shown in FIG. Temperature control having a temperature characteristic that does not occur can be performed.

In this case, not only the absolute values of the fuzzy inference unit 14 and the first temperature detecting element 10 but also the degree of change and the second
By performing the inference including the detection of the temperature due to the deformation of the pot bottom by the temperature detecting element 12, it is possible to quickly respond to a temperature change such as a disturbance inside the cooking vessel 1 and to cope with the deformation of the pot bottom.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to a block diagram of FIG.

In this figure, the present embodiment is different from the first embodiment shown in FIG. 1 in that a differentiating circuit for outputting the degree of change of the output of the first temperature detecting element 10 is the same as in the first embodiment. 11
Is changed to the first differentiating circuit 11a, and the second
The point that a second differentiating circuit 15 for outputting the degree of change of the output of the temperature detecting element 12 is provided, and the heat collecting plate temperature membership function storage circuit 14e and the heat collecting plate temperature adaptability calculating circuit 14f of the fuzzy inference unit 14 are provided. The difference is that the heat collecting plate temperature change membership function storage circuit 14i and the heat collecting plate temperature change adaptability calculating circuit 14j connected to the second differentiating circuit 15 are replaced. The other components are the same as those of the first embodiment, and therefore, the same components are denoted by the same reference numerals and description thereof will be omitted.

The operation of the electromagnetic cooker configured as described above will be described.

In the present embodiment, the heat collecting plate temperature change adaptability calculating circuit 14j receives the change in the detected temperature of the second temperature detecting element 12 from the second differentiating circuit 15 and inputs it to the setting input device 13. Based on the set temperature, it is inferred whether the current temperature state is high, low, or normal based on the rules stored in the heat collecting plate temperature change membership function storage circuit 14i. As in the first embodiment, the output suitability calculating circuit 14h combines the inference results of the suitability calculating circuits 14b, 14d, and 14j for the temperature, the slope, and the temperature change of the heat collecting plate, and stores the output membership function. The optimum output of the induction heating coil is inferred by the circuit 14g. By repeating the above operation, a stable temperature characteristic shown in FIG. 3 is obtained. Also in this case, high performance can be obtained that can respond quickly to a temperature change such as a disturbance inside the cooking vessel 1 and can cope with deformation of the pot bottom.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to a block diagram of FIG.

In this figure, the present embodiment is similar to the first embodiment shown in FIG.
The difference from the second embodiment is that the heat collecting plate 4 and the second temperature detecting element 12
In place of the above, an output power detection device 16 for detecting the output of the induction heating coil 3 from the output of the high-frequency inverter output control circuit 6b of the coil current control device 6 is provided. Plate temperature membership function storage circuit 14e
And the output power membership function storage circuit 14k and the output power compatibility calculation circuit connected to the output power detection device 16 in place of the heat collecting plate temperature compatibility calculation circuit 14f.

[0037]

[Outside 1]

The same reference numerals are given to the same symbols, and the description is omitted.

The operation of the electromagnetic cooker configured as described above will be described.

In this embodiment, the output power membership function storage circuit 14k has a fitness estimating rule for each set temperature in order to estimate an optimum output set value suitable for each set temperature.

[0041]

[Outside 2]

Based on the input set temperature and the rules stored in the output power membership function storage circuit 14k,
It infers whether the current output state is large, small, or normal. Output membership function storage circuit 14g
Is the temperature, slope and output power

[0043]

[Outside 3]

There is a rule for setting the optimum output by combining the fruits, and the output suitability calculating circuit 14h further infers the optimum output of the induction heating coil 3. In this case, if the detected temperature is low in spite of the fact that the output is high from the output of the induction heating coil 3 or, similarly, the slope of the detected temperature change is negative, the output adaptability calculating circuit 14h Since it can be determined that there is much, the output is determined to be higher.
Since the above operation is repeated, stable temperature characteristics with high accuracy can be obtained. Further, since the fuzzy inference unit 14 infers not only the absolute value of the first temperature detecting element 10 but also the degree of change and the output power, it can respond quickly to a temperature change such as a disturbance inside the cooking vessel 1. High performance can be obtained.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to a block diagram of FIG.

In this figure, the present embodiment differs from the third embodiment shown in FIG. 5 in that an output power differentiating circuit 17 for outputting the degree of change of the detected power of the output power detecting device 16 is provided. Points, and in the fuzzy inferencer 14, an output power membership function storage circuit 14k and

[0047]

[Outside 4]

The difference is that an output power gradient adaptability calculating circuit 14n connected to the output power differentiating circuit 17 is provided. The other parts are the same as those of the third embodiment, and therefore, the same components are denoted by the same reference numerals and description thereof will be omitted.

The operation of the electromagnetic cooker configured as described above will be described.

In this embodiment, the output power gradient membership function storage circuit 14m has a fitness estimation rule for each set temperature in order to estimate a set value of an optimum output suitable for each set temperature. The output power slope matching degree calculation circuit 14n
The slope of the detected power from the output power differentiating circuit 17 is input, and based on the input set temperature and the rules stored in the output power slope membership function storage circuit 14m, whether the current power change is increasing, Infer if it is down or normal. The output membership function storage circuit 14g stores the fitness degree calculation circuits 14 for the temperature, the slope, and the output power slope.
Based on the inference results of b, 14d, and 14n, an output adaptation degree calculation circuit 14h infers an optimum output of the induction heating coil. In this case, when the detected temperature is low or the slope of the detected temperature change is negative even if the output of the heating coil indicates an increase, Has changed a lot,
Determine the output even higher.

Since the above operation is repeated, a highly accurate and stable temperature characteristic can be obtained. Further, the fuzzy inference unit 14 infers not only the absolute value of the first temperature detecting element 10 but also the degree of change and the change in output power.
High performance that can respond quickly to temperature changes such as internal disturbances can be obtained.

[0052]

As described above, according to the present invention,
Since the fuzzy inferencer has knowledge and know-how to determine the optimal heating output for the detected temperature input and performs output control, the magnetic flux generated by the induction heating coil is affected by the self-heating heat collecting plate. The temperature control output is set in consideration of the temperature detected by the heat collecting plate, and stable and accurate even in pots with an uneven bottom. A high temperature control device is obtained.

Further, by inputting the change in the temperature detected by the heat collecting plate, the temperature of the pot having the bottom shape can be controlled with high accuracy and high responsiveness.

Further, the output of the induction heating coil is detected, and when the detected temperature is low despite the high output, or
If the slope of the detected temperature change is negative, it can be determined that the amount of heat consumed by the load is large, and the output can be determined to be higher to further improve the temperature control performance.

Further, when the change in the output of the induction heating coil is detected and the detected temperature is low or the slope of the detected temperature change is negative despite the increase in the output, the amount of heat consumed by the load is large. It can be determined that the temperature has changed, and the output can be determined to be higher to further improve the temperature control performance.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electromagnetic cooker according to a first embodiment of the present invention.

FIG. 2 is a state diagram showing an inference operation of the fuzzy inference device.

FIG. 3 is a temperature characteristic diagram of the electromagnetic cooker according to the present invention.

FIG. 4 is a block diagram of an electromagnetic cooker according to a second embodiment.

FIG. 5 is a block diagram of an electromagnetic cooker according to a third embodiment.

FIG. 6 is a block diagram of an electromagnetic cooker according to a fourth embodiment.

FIG. 7 is a block diagram showing a configuration of a conventional electromagnetic cooker.

FIG. 8 is a view showing the shape of the bottom of the pan.

FIG. 9 is a temperature control characteristic diagram of a conventional electromagnetic cooker.

FIG. 10 is a temperature control characteristic diagram of a conventional electromagnetic cooker.

[Explanation of symbols]

1 ... cooking vessel, 2 ... top plate, 3 ... induction heating coil,
4 heat collecting plate, 5 temperature detecting element, 6 coil current control device, 6a high frequency inverter circuit, 6b high frequency inverter output control circuit, 7 comparator, 8 setting variable resistor, 9 resistance, 10th 1 temperature detecting element, 11: differentiating circuit, 11a: first differentiating circuit, 12: second temperature detecting element, 13: setting input device, 14: fuzzy inference device, 14
a: Temperature membership function storage circuit, 14b: Temperature suitability calculation circuit, 14c: Slope membership function storage circuit, 1
4d: slope matching degree calculating circuit, 14e: heat collecting plate temperature membership function storage circuit, 14f: heat collecting plate temperature matching degree calculating circuit, 14g: output membership function storing circuit, 14h: output matching degree calculating circuit, 14i ... Heat collecting plate temperature change membership function storage circuit, 14j: Heat collecting plate temperature change adaptability calculation circuit, 14k: Output power member

[Outside 5] Membership function storage circuit, 14n: output power gradient adaptability calculation circuit, 15: second differentiation circuit, 16: output power detection device, 17: output power differentiation circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05B 6/12

Claims (4)

(57) [Claims] 1. An electromagnetic cooker comprising at least a top plate on which a cooking vessel such as a pan is placed and an induction heating coil for electromagnetically heating the pan, wherein an electromagnetic cooker attached to the lower surface of the top plate and at the center of the induction heating coil. (1) a temperature detecting element, a second temperature detecting element mounted on a heat collecting plate mounted on the lower surface of the top plate and at the center of the induction heating coil, and a temperature differential for outputting a differential value of a detected temperature of the first temperature detecting element. Fuzzy inference for determining the output of the induction heating coil by fuzzy inference based on the arithmetic unit, the detected temperature of the first temperature sensing element, the output of the temperature differential arithmetic unit, the output of the second temperature sensing element, and the input value of the set temperature An electromagnetic cooker comprising: a cooking device; and a coil current control means for controlling a current supplied to the induction heating coil by an output of the fuzzy inference device to control an output of the coil. 2. An electromagnetic cooker comprising at least a top plate on which a cooking vessel such as a pan is placed and an induction heating coil for electromagnetically heating the pan, wherein the electromagnetic cooker is mounted on the lower surface of the top plate and at the center of the induction heating coil. (1) a temperature detecting element, a second temperature detecting element mounted on a heat collecting plate mounted on the lower surface of the top plate and at the center of the induction heating coil, and a temperature differential for outputting a differential value of a detected temperature of the first temperature detecting element. A calculating device, a second temperature differential calculating device for outputting a differential value of a detected temperature of the second temperature detecting element, a detected temperature of the first temperature detecting element, an output of the temperature differential calculating device, and a second temperature differential calculating device. A fuzzy inference device that determines the output of the induction heating coil by fuzzy inference based on the output value of the output and the input value of the set temperature, and controls the current supplied to the induction heating coil by the output of the fuzzy inference device to control the output of the coil. An electromagnetic cooker, comprising: a coil current control unit that performs heating. 3. An electromagnetic cooker comprising at least a top plate on which a cooking vessel such as a pan is placed, and an induction heating coil for electromagnetically heating the pan, wherein a temperature attached to the lower surface of the top plate and at the center of the induction heating coil. A detection element, an output detection element for detecting the output power of the induction heating coil, a temperature differential operation device for outputting a differential value of a detected temperature of the temperature detection element, a detected temperature of the temperature detection element, and an output of the temperature differential operation device A fuzzy inference device that determines the output of the induction heating coil by fuzzy inference based on the detected value of the output detection element and the input value of the set temperature, and a coil that controls the current supplied to the induction heating coil by the output of the fuzzy inference device. An electromagnetic cooker comprising coil current control means for controlling the output of the electromagnetic cooker. 4. An electromagnetic cooker comprising at least a top plate on which a cooking vessel such as a pan is placed and an induction heating coil for electromagnetically heating the pan, wherein a temperature attached to the lower surface of the top plate and at the center of the induction heating coil. A detection element, an output detection element for detecting the output power of the induction heating coil, a temperature differential operation device for outputting a differential value of the detected temperature of the temperature detection element, and an output differentiation for outputting a differential value of the detection value of the output detection element Based on the calculation device and the detected temperature of the temperature detection element, the output of the temperature differentiation calculation device, the detection value of the output detection element, the output of the output differentiation calculation device, and the input value of the set temperature, the induction heating coil A fuzzy inference device for determining an output, and a coil current control means for controlling a current supplied to the induction heating coil by an output of the fuzzy inference device and controlling an output of the coil. Electromagnetic cooker.