JPH11317285A - Temperature controlling method of induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cooking utensil from being heated beyond the preset temperature, during the process from the turning on the electromagnetic cooking device to start the heating of the cooking utensil until the heating temperature gets to the preset temperature. SOLUTION: The following temperature controlling method is applied to an induction heating cooker 1 constituted by putting a magnetic cooking utensil 4 in a magnetic field generated by passing an alternating current through an induction heating coil 3 to heat and cook foodstuffs in the cooking utensil 4. That is, when the cooking utensil 4 is heated after the induction heating coil 3 is turned on, as the heating temperature Q gets close to the preset temperature required for the cooking, a temperature-up rate ΔQ/Δt of the cooking utensil 4 is gradually decreased. Then, the cooking by heating of the foodstuff is finished at the point when the temperature-up rate substantially reaches zero. This is performed by lengthening, by degrees, the time Δt during which the electric power supplied to the induction heating coil 3 is increased in phase by the prescribed amount of change of the power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control method for preventing a heating temperature of a cooking utensil of a food from being overheated above a set temperature when starting an electromagnetic cooker.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventionally known electromagnetic cooker 1 usually has an induction heating coil 3 installed inside a housing 2 and a space above the coil 3 via a space. A cooking utensil 4 such as a magnetic pot or a plate on which the food is placed is installed, and an alternating current is passed to the coil 3 by a power control device installed in the housing 2 to cause the cooking utensil 4 to be magnetically driven. It is designed to be placed inside and heated by dielectric.

When the power of the electromagnetic cooker 1 having this structure is turned on to cause the cooking utensil 4 to generate heat, usually, a cooking temperature (hereinafter, referred to as a set temperature) necessary for cooking the food is determined and the electromagnetic cooker is determined. 1 stores the set temperature and the cooking utensil 4
Until the heat generation temperature reaches the set temperature.

[0004] When the heat generation temperature reaches the set temperature, the control device incorporated in the electromagnetic cooker 1 is operated to turn off the power so that the heat generation temperature of the cooking utensil 4 further increases. Suppress. If the cooking is continued in this state, the heat is generated in the cooking utensil 4 and the food is also deprived of heat, so that the temperature of the cooking utensil 4 naturally drops to become lower than the set temperature. Then, the control device is operated again to turn on the power and the cooking utensil 4 starts to generate heat.

[0005]

However, when such a method for controlling the temperature of an electromagnetic cooker is employed, there are the following problems. That is, as shown by the curve U in FIG. 8, even if the heating is stopped at the time t1 when the heating temperature Q of the cooking utensil 4 reaches the set temperature Qs after the coil 3 starts to be energized, the cooking utensil 4 However, due to its nature, a material having a large heat capacity is usually used, so that there is a problem that the temperature of the cooking utensil 4 continues to rise and the same is overheated to the set temperature Qs or higher.

Conversely, there is a problem that the temperature of the cooking utensil 4 does not immediately rise even when the power is turned on from the time t2 when the heat generation temperature Q of the cooking utensil 4 drops. As a result, cooking utensil 4
The actual temperature of forms a large-amplitude wave around the set temperature Ts, and during this time, the cooked food proceeds. Therefore, cooking with the cooking utensil 4 that changes in temperature in this way not only makes it difficult to make a dish that truly utilizes the characteristics of the ingredients, but also consumes extra power supplied to the induction heating coil.

An object of the present invention is to turn on the power of an electromagnetic cooker.
In order to avoid overheating of the cooking utensil in the process from starting heating the cooking utensil to reaching the set temperature,
An object of the present invention is to provide a method for controlling the temperature of an electromagnetic cooker. As a method of minimizing the above-described problem, there is a control method of reducing the amplitude of the wave. However, this method not only loses smoothness in controllability but also increases control deviation and consequently temperature control width. (Difference from the set temperature) increases.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a magnetic cooking utensil containing foodstuffs in a magnetic field generated by passing an alternating current through an induction heating coil at a predetermined temperature. In the process of heating and cooking the food while heating, as the heat generation temperature of the cooking utensil approaches the set temperature after energizing the induction heating coil,
Means is employed in which the electric power applied to the induction heating coil is changed so that the temperature rise rate of the magnetic cooking utensil gradually decreases.

As a specific method of changing the power, a method of gradually reducing the amount of change in power applied to the induction heating coil per unit time, particularly, gradually increasing the power application time while keeping the change in power constant. Adopt a method to make it. Then, during cooking of foodstuffs, a means is adopted in which the heating rate is set to substantially zero and the heat generation temperature of the cooking utensil is adjusted to the set temperature. In these embodiments, a means for changing the current is preferably employed as the means for changing the power.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the most preferred embodiment of the present invention will be described in detail with reference to FIG. 3. An electromagnetic cooker 1 according to the present invention has a housing 2 similar to a conventionally known one. A carp 3 is installed above the inside, a cooking utensil 4 is installed above the induction heating coil 3 via a space, and an alternating current is supplied to the coil 3 by power adjusting means A installed in the housing 2. It has a structure to pass through.

Further, control means B for controlling the amount of electric power supplied to the electric power adjusting device A is incorporated in the housing 2. In addition, as the cooking utensil 4, other than a pot-shaped container for storing the food material, a magnetic material for mounting the food material like an iron plate is also used.

The power adjusting means A mainly comprises a three-phase power supply terminal 9, a diode rectifier 10 and a power transistor 11, as in the well-known art. When the power is turned on, the power drives the diode rectifier 10 and the power transistor 11. The induction heating coil 3 generates magnetism.

The control means B mainly includes the control device 1
2. It comprises a microcomputer (microcomputer) 13, knob 6, and variable resistor 14, and operates as follows to control the heat generation temperature of the cooking utensil 4. That is, the knob 6 provided on the side of the housing 2 is turned, and a signal a corresponding to the turning amount is sent from the variable resistor 14 to the microcomputer 1.
3, the microcomputer 13 sends a signal b to the control device 12. Then, the control device 12 sends a signal c to the power transistor 11 and supplies power corresponding to the turning angle of the knob 6 to the induction heating coil 3.

On the other hand, the control device 12 controls the induction heating coil 3
When the power supply amount is detected by the signal d while the power is supplied to the microcomputer 13 and the result is transmitted to the microcomputer 13 as the signal e, a signal f corresponding to the rotation amount of the knob 6 is sent to the power display unit 5. As a result, the power display unit 5 displays information corresponding to the amount of power input to the induction heating coil 3.

The microcomputer 13 has a cooking temperature that differs depending on the type of food, that is, a set temperature Qs, and a heating temperature Q at which the cooking utensil 4 generates heat after the start of use of the electromagnetic cooker.
Is quickly and accurately entered to the set temperature Qs.
The heating temperature of the cooking utensil 4 can be constantly sampled by the temperature sensor 7.

In this embodiment, the program is:
As shown by a curve X in FIG.
The temperature difference ΔQ at which the temperature has risen per contact, that is, the heating rate ΔQ / Δ
t gradually decreases as the temperature approaches the set temperature Qs, and when the heat generation temperature Q of the cooking utensil 4 finally approaches the set temperature Qs, the heating rate is reduced to substantially zero and the heat generation temperature Q becomes the set temperature Qs. The program is a program for controlling the electric power applied to the induction heating coil 3, preferably the electric current, with the passage of time so as to change the electric power.

More specifically, first, the temperature at which the cooking utensil 4 is heated by dielectric heating has a linear relationship with the magnitude of the electric power applied to the induction heating coil 3. Is changed, the heat generation temperature Q of the cooking utensil 4 is changed.

In the method of controlling the voltage, the voltage is not changed continuously with time, but is changed for a predetermined time Δ
Each time t elapses, the power is gradually increased by a constant power change amount Δp.
As shown in FIG. 7, the current gradually increases with the lapse of the power supply start time t for the dielectric heating coil 3 at each stage. Then, the heating rate ΔQ / Δt is changed to the set temperature Qs.
It gradually decreases as it approaches.

Next, the operation and effect of the electromagnetic cooker configured as described above will be described.
Enter the initial condition in 3. That is, the value based on the temperature deviation ΔQ is determined by the unit time Δt
The condition of how much to hit is input to the microcomputer 13.

Next, the power supply 9 of the alternating current generating means A is turned on.
When the coil 3 is turned on and the coil 3 is energized, the microcomputer 13
Sends an instruction signal b to the control device 12 and drives the power transistor 11 so that the power up to that time is increased by a predetermined power change amount Δp every time the time instructed according to the control program elapses. Then, the heat generation temperature Q of the cooking utensil 4 continuously rises.

In the process of increasing the power of the induction heating coil 3 to increase the heat generation temperature Q of the cooking utensil 4 in the initial stage, as shown by the curve Z in FIG. According to the present invention, the heating rate of the heating temperature Q is set so as to gradually decrease as the heating temperature Q approaches the setting temperature Qs. Therefore, the heating temperature Q is suppressed as the heating temperature Q approaches the setting temperature Qs. It does not become higher than the temperature Qs.

Finally, the heat generation temperature Q is equal to the set temperature Qs
If the food is cooked in the process, not only can the food be cooked at a temperature suitable for the food, but also, as shown by the curve W, the heat generation temperature Q is set to the set temperature Qs.
, The power consumption during cooking after being brought close to the food can be reduced.

Such temperature control is continued as long as there is a difference (Qs-Q) between the set temperature Qs and the temperature Q of the cooking utensil 4, so that at a certain time t1, the food is put into the cooking utensil. Even if the heat generation temperature Q is temporarily lowered, the temperature control is started again according to the program. As a result, a wave-like temperature change having a large amplitude as in a conventionally known electromagnetic cooker is not caused, and power consumption can be suppressed to the minimum necessary.

The present invention can be implemented by partially modifying the above-described embodiment, for example, as long as the basic technical concept is followed and the effect of the invention is not significantly impaired. (1) As a method of gradually decreasing the temperature increase rate ΔQ / Δt as it approaches the set temperature Qs, as shown in FIG. 5, a method of stepwise decreasing a power change amount Δp of the electric power P to be increased every predetermined time Δt. May be adopted. In some cases, the power change amount Δp that is increased stepwise as time elapses from the start of energization of the dielectric heating coil may be reduced, and the time Δt for maintaining the power change amount Δp may be gradually reduced.

(2) The heating rate ΔQ / Δt is equal to the set temperature Qs
May be started not only immediately after the start of energization of the dielectric heating coil but also after a lapse of a predetermined time. In this case, as shown by a dashed line m in FIG. 6, the heating temperature Q is raised to a value close to the set temperature Qs as quickly as possible while keeping the heating rate constant until the predetermined time t3 from the start of energization, and then the curve n, the heating rate ΔQ / Δt
, The cooking cycle can be shortened. In this embodiment, there are a plurality of logical expressions to be stored in the microcomputer, and it is necessary to instruct when to set the predetermined time t3.

(3) In order to finally bring the exothermic temperature Q closer to the set temperature Qs, the settled exothermic temperature Q should only be the optimal cooking temperature of the foodstuff. Is, as shown by the chain line in FIG.
Depending on the logical expression, a virtual temperature can be set as the set temperature based on the stable and calm heat generation temperature.

[0027]

As described above in detail, according to the present invention, when the power of the electromagnetic cooker is turned on and heating of the cooker is started until the cooker reaches the set temperature, the cooker reaches the set temperature. Q
It has an excellent effect that it is not overheated. As a result, not only can the food be cooked well at a cooking temperature suitable for it, but also an additional effect that extra power is not consumed is exhibited.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a typical temperature control method of the present invention.

FIG. 2 is a diagram illustrating one embodiment of a voltage control method.

FIG. 3 is a conceptual diagram showing a configuration of an electromagnetic cooker according to the present invention.

FIG. 4 is a diagram showing a relationship between heat generation temperature and power consumption.

FIG. 5 is a diagram showing another embodiment of the voltage control method.

FIG. 6 is a diagram showing another temperature control method.

FIG. 7 is a perspective view of an electromagnetic cooker according to the present invention.

FIG. 8 is a diagram showing a heating rate and power consumption according to the related art.

[Explanation of symbols]

 Reference Signs List 1 electromagnetic cooker 2 housing 3 induction heating coil 4 cooking utensil 7 temperature sensor P voltage Q heat generation temperature Qs set temperature

Claims (6)

[Claims] When a magnetic cooking utensil (4) is placed in a magnetic field generated by passing an alternating current through an induction heating coil (3) and the cooking material of the cooking utensil is heated and cooked, the induction heating coil is supplied to the induction heating coil. As the heating temperature (Q) of the cooking utensil approaches the set temperature (Qs) required for cooking the foodstuffs after the energization is started,
A method for controlling the temperature of an electromagnetic cooker, wherein the electric power (P) applied to the induction heating coil is changed so that the heating rate (ΔQ / Δt) of the cooker is gradually reduced. 2. The temperature control of an electromagnetic cooker according to claim 1, wherein the change of the electric power (P) is a method of gradually decreasing an amount of change in electric power applied to the induction heating coil (3), which increases per unit time. Method. 3. The temperature control method for an electromagnetic cooker according to claim 2, wherein the method of gradually reducing the amount of change in the power is a method in which the amount of change in the power is kept constant and the application time of the power is gradually increased. 4. The temperature control method for an electromagnetic cooker according to claim 1, wherein the change of the electric power (P) is a method of changing a current. 5. A magnetic cooking utensil (4) placed in a magnetic field generated by passing an alternating current through an induction heating coil (3) to heat and cook the ingredients of the cooking utensil. Is the set temperature (Q) required for cooking the food.
s), the heating rate of the cooking utensil (ΔQ / Δt) is gradually reduced after energization of the induction heating coil is started, and the heating rate becomes substantially zero during heating and cooking of the foodstuff. A method for controlling the temperature of an electromagnetic cooker, wherein the power (P) applied to the induction heating coil is changed. 6. The temperature control method for an electromagnetic cooker according to claim 5, wherein the change of the electric power (P) is a method of changing a current.