JPH11111438A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat load suitable for induction heating effectively and surely. SOLUTION: An input suppression means 19 judges whether an input is suitable for induction heating or not in response to the output of a voltage detection means 18 for the output of an input detection means 17 corresponding to load 14, and the input to an inverter circuit is suppressed in response to the judgement. Since the input suppression means 19 is equipped with two kinds or more of input suppression states of the inverter circuit, the induction heating is stopped for no load, a small article load such as a knife, or a pan unsuitable for the induction heating, and the induction heating is conducted at a predetermined input to the load 14 judged as unsuitable for the induction heating by any cause though suitable for the heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction cooking device.

[0002]

2. Description of the Related Art In recent years, an induction heating cooker utilizes a good heating response to mount a temperature detecting element or the like in the vicinity of a pot or the like serving as a load, and detects the temperature of the pot or the like to adjust the heating power. In addition to realizing fine cooking, the characteristic of being safe and clean because it does not use flames and does not pollute indoor air is attracting attention, and its demand is rapidly growing.

A conventional induction heating cooker detects a load characteristic by detecting a load characteristic according to a voltage value such as a voltage across a switching means or a current value flowing through a heating coil or a switching means with respect to an input current of an inverter circuit. Detects the load state, the load that should not be heated such as knife, spoon, kitchen knife, etc., and the load that is not suitable for induction heating, such as aluminum pan, is about to be heated, and limits the input to the inverter circuit. To prevent overheating of inappropriate loads. At this time, the input to the inverter circuit is limited by improper load in the process of starting heating, the control circuit gradually increasing the ON time of the switching means, and the input of the inverter circuit gradually increasing accordingly. As soon as it is detected, heating is temporarily stopped, and heating is restarted after a predetermined time.If this continues for a predetermined time, the heating operation is stopped. This was to cancel the pot detection state and start normal heating.

[0004]

However, in the above-described conventional induction heating cooker, heating is stopped after a predetermined time as described above if the condition of improper load is satisfied under any conditions. It has a characteristic that is determined to be an appropriate load at the time of low input, but if a load is heated such that it becomes a characteristic that is determined to be an improper load when the input increases,
When heating a load having the characteristics of an appropriate load at any input, the magnetic coupling between the load and the heating coil becomes smaller, for example, the distance between the load and the heating coil increases,
If the load deviates significantly from the center of the heating coil, it is eventually determined to be an improper load, an improper load is displayed, and heating is stopped after a predetermined time, which is inconvenient for the user. Had.

The present invention has been made to solve the above problems, and detects an improper load in accordance with an output voltage of an inverter circuit or a current flowing through the inverter circuit with respect to an input to the inverter circuit, thereby suppressing input of the inverter circuit. By providing more than one kind, by using the input suppression of the inverter circuit properly, induction heating is performed even on a load that is detected as an improper load, even though it is suitable for induction heating, and a certain amount of input is given, and cooking cannot be performed. It is an object of the present invention to provide a more convenient induction heating cooker in which the possibility of occurrence of such a problem is reduced.

[0006]

According to the present invention, there is provided a control circuit for controlling an operation of an inverter circuit, an input detecting means for detecting an input of the inverter circuit,
Since it has the voltage detecting means for detecting the high frequency voltage generated in the inverter circuit, it is possible to detect the operation state of the inverter circuit according to the load. Also, the input suppression means determines whether or not the inverter circuit is suitable for induction heating according to the output of the voltage detection means with respect to the output of the input detection means which is the operation state of the inverter circuit corresponding to the load. Circuit input can be suppressed. Further, since the input suppression means has at least two types of input suppression states of the inverter circuit, induction heating is stopped in a no-load, a small object load such as a knife, or a pan or the like that is not suitable for induction heating. For a load that can be determined to be inappropriate for induction heating for some reason, heating can be performed with a desired input or a predetermined input.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 includes an inverter circuit including a heating coil and switching means for converting a direct current into a high frequency alternating current and supplying a high frequency current to the heating coil, and an operation of the inverter circuit. A control circuit for controlling the input circuit, wherein the control circuit detects input of the inverter circuit, voltage detection means for detecting a high-frequency voltage generated in the inverter circuit, According to the output of the voltage detecting means, the apparatus has an input suppressing means for suppressing the input of the inverter circuit, and the input suppressing means has at least two or more kinds of input suppressing states. Driving the switching means of the inverter circuit,
A high-frequency current is supplied to the heating coil, and a load such as a pot can be induction-heated by the magnetic flux generated from the heating coil.

The input detecting means detects an input to the inverter circuit, the voltage detecting means detects a high-frequency voltage value generated by the inverter circuit, and the characteristic of the output of the voltage detecting means with respect to the output of the input detecting means depends on the load. So different
According to the output of the voltage detection means with respect to the output of the input detection means, the input suppression means can detect the operation state of the inverter circuit, and whether the load to be heated is suitable for induction heating or may be heated. It is possible to determine whether or not. Therefore, the control circuit can output a control signal based on the judgment of the input suppression means to the inverter circuit, and can suppress the input of the inverter circuit.

Further, since the input suppression means has at least two or more types of input suppression states, it differs depending on the load.
This has the effect that a desired input suppression state can be selected from a plurality of input suppression states according to the characteristics of the output of the voltage detection means with respect to the output of the input detection means.

According to a second aspect of the present invention, there is provided an inverter circuit including a heating coil and switching means for converting a direct current into a high frequency alternating current and supplying a high frequency current to the heating coil, and a control for controlling the operation of the inverter circuit. A control circuit for detecting an input of the inverter circuit, a current detection unit for detecting a current flowing through the inverter circuit, and an output of the current detection unit with respect to an output of the input detection unit. Accordingly, there is provided input suppression means for suppressing the input of the inverter circuit, wherein the input suppression means has at least two types of input suppression states. To supply a high-frequency current to the heating coil, and induction heating of a load such as a pan by the magnetic flux generated from the heating coil Rukoto can.

The input detecting means detects the input to the inverter circuit, the current detecting means detects the value of the current flowing through the inverter circuit, and the characteristic of the output of the current detecting means with respect to the output of the input detecting means differs depending on the load. According to the output of the current detection means with respect to the output of the input detection means, the input suppression means can detect the operation state of the inverter circuit, whether the load to be heated is suitable for induction heating, or even if heated It is possible to judge whether it is good or not. Therefore, the control circuit can output a control signal based on the judgment of the input suppression means to the inverter circuit, and can suppress the input of the inverter circuit.

Further, since the input suppression means has at least two or more kinds of input suppression states, it differs depending on the load.
This has the effect that a desired input suppression state can be selected from a plurality of input suppression states according to the characteristics of the output of the current detection means with respect to the output of the input detection means.

According to a third aspect of the present invention, there is provided an inverter circuit which includes a heating coil and a switching means, converts direct current into high frequency alternating current, and supplies a high frequency current to the heating coil, and control for controlling the operation of the inverter circuit. A control circuit, wherein the control circuit detects an input of the inverter circuit, an input detection unit detects a high-frequency voltage generated in the inverter circuit, and a current detection unit detects a current flowing in the inverter circuit. A first input suppressing unit that suppresses an input of the inverter circuit according to an output of the voltage detecting unit with respect to an output of the input detecting unit; and a first input suppressing unit that responds to an output of the current detecting unit with respect to an output of the input detecting unit. And second input suppressing means for suppressing the input of the inverter circuit, wherein at least the first and second input suppressing means are provided. Are those where one has a structure comprising at least two or more input suppression state, the control circuit drives the switching means of the inverter circuit,
A high-frequency current is supplied to the heating coil, and a load such as a pot can be induction-heated by the magnetic flux generated from the heating coil.

The input detecting means detects an input to the inverter circuit, the voltage detecting means detects a high-frequency voltage value generated by the inverter circuit, and the characteristic of the output of the voltage detecting means with respect to the output of the input detecting means depends on the load. So different
The first input suppression means can detect the operation state of the inverter circuit in accordance with the output of the voltage detection means with respect to the output of the input detection means. It is possible to judge whether or not to do so. Therefore, in the control circuit, the first input suppressing unit can output a control signal based on the determination to the inverter circuit, and can suppress the input of the inverter circuit.

Similarly, the current detecting means detects the value of the current flowing through the inverter circuit, and the characteristic of the output of the current detecting means with respect to the output of the input detecting means differs depending on the load.
The second input suppression means can detect the operation state of the inverter circuit in accordance with the output of the current detection means with respect to the output of the input detection means, and determine whether the load to be heated is suitable for induction heating, or It is possible to determine whether or not it is OK. Therefore, the control circuit can output a control signal based on the judgment of the second input suppressing means to the inverter circuit, and can suppress the input of the inverter circuit.

Further, since the first and second input suppression means each have an input suppression state, it is desired to individually heat a plurality of loads having different characteristics and to suppress the input to a desired load among them. In the case, even if one of the characteristics of the output of the voltage detection means or the output of the current detection means with respect to the output of the input detection means does not have a difference in the characteristics and the input cannot be suppressed only to a desired load, the other side has the characteristics. When there is a difference, there is an effect that the input can be suppressed by the first or second input suppression limit means capable of detecting the difference in characteristics.

According to a fourth aspect of the present invention, in the third aspect of the invention, at least one of the first and second input suppression means has at least two types of input suppression states. And at least one of the second input suppression means has at least two or more types of input suppression states, so when individually heating a plurality of loads having different characteristics, the voltage detection means or the current with respect to the output of the input detection means Even if one of the characteristics of the output of the detection means cannot be changed to a different input suppression state without a difference in the characteristics,
On the other hand, when there is a difference in the characteristics, two or more types of input suppression states can be set in the first or second input suppression means capable of detecting the difference in the characteristics. There is an effect that a desired input suppression state can be set from a plurality of input suppression states according to the characteristics of the output of the voltage detection means or the output of the current detection means with respect to the output of the detection means, and different input suppression states can be set.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the control circuit has a notifying means, and the notifying means corresponds to a plurality of input suppression states provided in the input suppression means. At least one notification is provided, and the notification means performs at least one notification for a desired input suppression state in accordance with the input suppression state set by the input suppression means. It has the effect of being able to.

According to a sixth aspect of the present invention, in the first aspect of the present invention, when the control means has a timer means, and the input suppression means suppresses an input of an inverter circuit, The timer means counts the time in the first input suppression state, and based on the count result, shifts the operation of the inverter circuit to a predetermined operation mode, and releases the first suppression state or enters the second input suppression state. For example, the timer means stops counting or clears the counted time, and the timer means can count the time in the first input suppression state. It is possible to shift the operation of the circuit to a predetermined operation mode. Also, the first suppression state is released or the second suppression state is released.
In the suppression state, the time counted by the counting means is suspended or cleared.
In this case, the input suppression means does not change the operation mode of the inverter circuit, and the load can be continuously heated with a desired input.

[0020]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention, FIG. 2 is a characteristic diagram of a voltage V across a switching means with respect to an input P of the first embodiment of the present invention, and FIG. FIG. 9 is a characteristic diagram of a current I flowing through a heating coil with respect to an input P of the first embodiment.

In FIG. 1, 11 is a commercial power supply, 12 is a rectifier circuit, 13 is a switching means 13a and a heating coil 1
3b, an inverter circuit for inductively heating the load pot 14 by applying a high-frequency current to the heating coil 13b, a control circuit 15 detects a drive means 16 for driving the switching means 13a, and an input to the inverter circuit 13 Input detecting means 17, a voltage detecting means 18 for detecting a voltage between both ends of the switching means 13 a, and an input detecting means 1.
7, an input suppressing means 19 for outputting a signal for suppressing the input to the inverter circuit 13 to the driving means 16 in response to the output of the voltage detecting means 18 with respect to the output of the inverter 7, and an inverter circuit 13 based on the output of the output of the input suppressing means 19. A notification unit 22 composed of a light emitting element or a piezoelectric element for notifying the user of the operation state of the user, and a timer unit for counting the time of the suppression state according to the suppression state output by the input suppression unit 19. 23 and a drive start means 24 composed of a switch or the like for outputting a signal for starting the operation of the inverter circuit 13 to the drive means 16. The input suppressing means 19 includes a first storage means M1 and a second storage means M
2 and the first storage means M1 is in the first suppressed state 19a.
And the second suppression state 19b are stored in advance, and the second storage means M2 stores in advance a condition for transition to one of the first suppression state 19a and the second suppression state 19b.

The operation of the above configuration will be described. When the user causes the driving means 16 to output a signal to start driving the switching means 13 a by the driving starting means 24, the driving means 16 switches the switching means 13 a of the inverter circuit 13.
Is turned on and off, the DC power obtained by rectifying the commercial power supply 11 by the rectifier circuit 12 is converted into a high-frequency AC power, a high-frequency current is supplied to the heating coil 13b, and the load 14 such as a pan is induction-heated by the magnetic flux generated from the heating coil 13b. Start.

Next, the driving means 16 gradually increases the ON time of the switching means 13a until the input detected by the input detecting means 17 reaches a desired input, and the heating coil 13b
The heating power of the load 14 is controlled by changing the high frequency current supplied to the load.

At the same time, the input suppressing means 19 is shown in FIG. 2A based on the input to the inverter circuit 13 detected by the input detecting means 17 and the voltage across the switching means 13a detected by the voltage detecting means 18. The characteristics of the input P and the voltage V across the switching means 13a which are different depending on the load 14 are constantly monitored. Generally, this characteristic is such that as the input P increases, the voltage V across the switching means 13a increases, and the heating coil 13b and the load 1
4, the increase in the voltage V across the switching means 13a increases even at low input (入 力 V / △).
P is large).

At this time, the input P to the switching means 13a
Is different depending on the load, the input-V voltage characteristic of the switching means 13a is different from that of FIG.
In the case of the characteristics A, B, and C in (a), when the load reaches the area X1 stored in the second storage unit M2, the input suppression unit 19 determines that the load 14 is inappropriate for induction heating. Is determined, the first input suppression state 19a is selected, and a signal for setting the first input suppression state 19a to the driving means 16 is output. At this time, the input suppression means 19 is in the first input suppression state 1.
9a is output to the notifying means 22 and the timer means 23. The notifying means 22 notifies the user that the load 14 is an inappropriate load, and the timer means 23 starts counting.

Here, the region X1 has a characteristic line (characteristic C) of a small load such as a knife, a non-load state (characteristic A), and an excessive current flowing or excessively flowing through the switching means 13a when heated like an aluminum pan. Characteristic line of load (characteristic B) which can clearly determine that the switching means 13a is not suitable for induction heating because there is a risk that the switching means 13a may be destroyed due to the application of a high voltage and loss.
Also, it is suitable for induction heating up to a certain input, but when the input is exceeded, an excessive current flows to the switching means 13a or an excessive voltage is applied, and the loss increases, and the switching means 13a is destroyed by a load which may be destroyed. It is set so as to include a characteristic line (characteristic D) part that may be affected.

In this embodiment, the first input suppression state 19a
In the case of the load 14 having the characteristic A, for example, the driving line 16 starts to drive the switching unit 13a and gradually increases the on-time thereof. For example, in the case of the load 14 having the characteristic A, the operation line of the characteristic A shown in FIG. In the case of A1, the switching means 13
Then, the operation of stopping the induction heating of the load 14 for about 2 seconds, and then restarting the driving of the switching means 13a is repeated.

When the timer 23 counts the time during which this operation is repeated and reaches one minute, the operation is stopped, and the driving start unit 24 sends a signal to the driving unit 16 to start driving the switching unit 13a. The state before output is established (called a standby mode). Within one minute,
When the characteristic line no longer intersects with the area X1 by changing to the load 14 such as the characteristic E in FIG.
Is determined to be an appropriate load, and the first input suppression state 19 is determined.
A signal for releasing a is output to the driving means 16 to start induction heating with a desired input, and the timer means 23 clears the time count and stops the notification by the notification means 22.

Such an intermittent heating operation is performed by detecting that an improper load such as a knife is being heated with as little input as possible, and preventing the improper load from becoming high in temperature. The inverter circuit 13 continues to operate with no load and a load 14 that is not suitable for induction heating, and the switching means 1
3a is prevented from being destroyed due to application of excessive electric / thermal stress, and within one minute, an inappropriate load is replaced with a load suitable for induction heating, or the load 14 is changed from a no-load state to a load suitable for induction heating. This is because it is possible to quickly detect the case of changing to the above.

When the voltage characteristic of the input P versus the voltage V across the switching means 13a is like the characteristic D of FIG. 2A, the voltage reaches the area X2 stored in the second storage means M2.
The input suppression unit 19 selects the second input suppression state 19b and outputs a signal to the driving unit 16 to set the second input suppression state 19b.

In the present embodiment, the second input suppression state 19b
The drive means 16 starts driving the switching means 13a and gradually increases the on-time thereof. For example, in the case of the load 14 having the characteristic D, the point where the operation line of the characteristic D shown in FIG. At D1, the switching means 13
Then, the operation of stopping the induction heating of the load 14 for about 2 seconds, and then restarting the driving of the switching means 13a is repeated. Within one minute,
When the characteristic line no longer intersects with the area X2 by, for example, changing to the load 14 such as the characteristic E in FIG.
Outputs a signal for releasing the second input suppression state 19b to the driving means 16 to start induction heating with a desired input.

Here, the second input suppression state 19b differs from the first input suppression state 19a in that the timer means 23 does not count the time during which this operation is performed. In this way, when the load 14 having the characteristic such as the characteristic D is being heated, cooking can be continued without entering the standby mode even after one minute has elapsed, and the first storage means can be provided. The common operation part of the first input suppression state 19a and the second input suppression state 19b stored in M1 can be shared, and the storage capacity of the first storage means M1 can be reduced.

Here, the area X2 includes the area X1 as shown in FIG. 2 (a). The area X1 is translated by a desired value in the positive direction of the horizontal axis, and the switching means is switched by a load like the characteristic D. 13a is set so as to include a region where excessive voltage and current are applied and there is no possibility of destruction. This is area X
By increasing the shared portion of X1 and X2, the storage capacity of the second storage means M2 storing the regions X1 and X2 can be reduced, and heating can be performed with as large an input as possible even under a load such as the characteristic D. That's why. Further, when the characteristics of the load 14 reach the regions X1 and X2 at the same time, it is determined that the load 14 has reached the region X1, and the first input suppression state 19a is set.

Further, in a state where heating is started with the load 14 having a characteristic such as the characteristic E and the heating is judged to be a pot suitable for induction heating, the distance between the heating coil 13b and the load 14 is increased,
The load 1 may be changed because the heating coil 13b and the load 14 are shifted.
When the magnetic coupling between the load 4 and the heating coil 13b is reduced, or when the magnetic characteristics of the load 14 gradually change with the rise in the temperature of the load 14, the characteristic becomes a characteristic D, and the input is suppressed. The load is determined and the second input suppression state 19 is set.
b to prevent the application of electric / thermal stress to the switching means 13a and the like.

Further, when the voltage characteristic between the input P and the voltage V across the switching means 13a is like the characteristic E in FIG. 2A, it does not reach either of the areas X1 and X2 stored in the second storage means M2. The input suppressing means 19 can output the signal to the driving means 16 and can heat the load 14 with a desired heating power.

As described above, according to the present embodiment, at the start of heating, it is possible to determine whether or not the heating is suitable for induction heating based on the characteristics of the input P and the voltage V across the switching means 13a and to notify the user of the heating. In the case where the input V versus the voltage V characteristics of the both ends of the switching means 13a changes in the middle due to the above-described cause, etc., the load is suitable for induction heating, but is not determined to be inappropriate, and the load is appropriate for induction heating for the user. However, it is possible to continue heating the load without applying an excessive electric / thermal stress to the switching means 13a or the like without notifying that the load is inappropriate.

As in the present embodiment, the second input suppression state 19b is intermittently called heating / non-heating.
3, the load 14 is not heated to heat the load 14. Instead, the operations of the first input suppression state 19a and the second input suppression state 19b are not shared and the second input suppression state 19b is continuously switched to a predetermined input. For example, the input Pd1 at the operating point D1 in FIG.
Needless to say, a method of maintaining the input Pc2 at the smaller operating point D2 and heating with an almost maximum input that can be heated with the load of the characteristic D may be used.

In this embodiment, the inverter circuit 13 includes one switching means. However, it is needless to say that the same effect can be obtained even if the inverter circuit 13 has two or more switching means. The input suppression means 19 has two types of input suppression states. However, it is needless to say that the same effect can be obtained and more detailed input suppression can be performed even if three or more kinds of input suppression states are provided. Further, the condition for shifting to each input suppression state is not limited to the condition of the present embodiment, and the voltage detected by the voltage detecting means 18 is not limited to the voltage across the switching means 13a.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention, and FIG. 4 is a characteristic diagram of the current I flowing through the heating coil with respect to the input P in the second embodiment of the present invention.

In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The control circuit 15 includes: a driving unit 16 that drives the switching unit 13a; an input detection unit 17 that detects an input to the inverter circuit 13;
A current detecting means 20 for detecting a high-frequency current flowing through the heating coil 13b; and an input for outputting a signal for suppressing an input to the inverter circuit 13 to the driving means 16 according to the output of the current detecting means 20 with respect to the output of the input detecting means 17. The suppression unit 21, a notification unit 22 configured by a light emitting element or a piezoelectric element for notifying the user of the operation state of the inverter circuit 13 based on the output of the input suppression unit 21, and an output of the input suppression unit 21. In accordance with the suppression state, there are provided timer means 23 for counting the time of the suppression state, and drive start means 24 constituted by a switch or the like for outputting a signal for starting the operation of the inverter circuit 13 to the drive means 16. doing. The input suppressing means 21 is provided in the first storage means M3
And a second storage unit M4. The first storage unit M3 previously stores the first suppression state 21a and the second suppression state 21b. The second storage unit M4 stores the first suppression state 21a and the second suppression state 21a. 2
The condition for shifting to any one of the suppression states 21b is stored in advance.

The operation of the above configuration will be described. When the user causes the driving means 16 to output a signal to start driving the switching means 13 a by the driving starting means 24, the driving means 16 switches the switching means 13 a of the inverter circuit 13.
Is turned on and off, the DC power obtained by rectifying the commercial power supply 11 by the rectifier circuit 12 is converted into a high-frequency AC power, a high-frequency current is supplied to the heating coil 13b, and the load 14 such as a pan is induction-heated by the magnetic flux generated from the heating coil 13b. Start.

Next, the driving means 16 gradually increases the ON time of the switching means 13a until the input detected by the input detecting means 17 reaches a desired input, and the heating coil 13b
The heating power of the load 14 is controlled by changing the high frequency current supplied to the load.

At the same time, the input suppressing means 21 is shown in FIG. 4A based on the input to the inverter circuit 13 detected by the input detecting means 17 and the current flowing through the heating coil 13b detected by the current detecting means 20. The characteristics of the input P and the current I flowing through the heating coil 13b that differ depending on the load 14 are constantly monitored. In general, the current I flowing through the heating coil 13b increases as the input P increases, and the magnetic coupling between the heating coil 13b and the load 14 decreases when the input P increases. (△ I / △ P is large).

At this time, the characteristics of the input P versus the current I flowing through the heating coil 13b differ depending on the load.
In the case where the characteristics of the current I flowing through the heating coil 13b are the characteristics F, G, and H in FIG. 4A, when the current reaches the area Y1 stored in the second storage unit M4, the input suppression unit 21
Determines that the load 14 is inappropriate for induction heating,
The first input suppression state 21a is selected, and a signal for setting the first input suppression state 21a to the driving means 16 is output. At this time, the input suppression means 21 outputs the first input suppression state 21a to the notifying means 22 and the timer means 23, and the notifying means 22 notifies the user that the load 14 is an inappropriate load, and The timer means 23 starts counting.

Here, the region Y1 has a characteristic line (characteristic H) of a small load such as a knife, a non-load state (characteristic F), and an excessive current flowing or excessively flowing through the switching means 13a when heated like an aluminum pan. Characteristic line of the load (characteristic G) which can clearly determine that the switching means 13a is not suitable for induction heating because there is a possibility that the switching means 13a may be broken due to the application of a large voltage and the loss increases.
Also, it is suitable for induction heating up to a certain input, but when the input is exceeded, an excessive current flows to the switching means 13a or an excessive voltage is applied, and the loss increases, and the switching means 13a is destroyed by a load which may be destroyed. It is set to include a characteristic line (characteristic J) portion that may cause a risk.

In this embodiment, the first input suppression state 21a
The drive means 16 starts driving the switching means 13a and gradually increases the on-time thereof. For example, in the case of the load 14 having the characteristic F, a point at which the operation line of the characteristic F shown in FIG. At F1, the switching means 13
Then, the operation of stopping the induction heating of the load 14 for about 2 seconds, and then restarting the driving of the switching means 13a is repeated. Further, the timer means 23 counts the time during which this operation is repeated, and
At this time, the operation is stopped and the driving start unit 24 enters a state (called a standby mode) before the driving unit 16 outputs a signal to start driving the switching unit 13a. Also, when the characteristic line no longer intersects with the area Y1 by changing the load 14 to the characteristic K in FIG. 4A within one minute, the input suppressing unit 21 determines that the load is appropriate,
The driving unit 1 outputs a signal for canceling the first input suppression state 21a.
6 to start the induction heating with a desired input, the timer means 23 clears the time count, and the notification by the notification means 22 is stopped.

Such an intermittent heating operation is performed by detecting that an improper load such as a knife is being heated with as little input as possible, and preventing the improper load from becoming high in temperature. The switching circuit 13a is prevented from being destroyed due to the inverter circuit 13 continuing to operate in a no-load state and a pot not suitable for induction heating, and the improper load is replaced with a load suitable for induction heating within one minute. This makes it possible to quickly detect when the load is changed from a no-load state to a load suitable for induction heating.

If the characteristic of the input P versus the current I flowing through the heating coil 13b is like the characteristic J in FIG. 4A, the current reaches the area Y2 stored in the second storage means M4. 21 selects the second input suppression state 21b and outputs a signal to the driving means 16 to set the second input suppression state 21b.

In the present embodiment, the second input suppression state 21b
The drive means 16 starts driving the switching means 13a and gradually increases the on-time thereof. For example, in the case of the load 14 having the characteristic J, the point at which the operation line of the characteristic J shown in FIG. At J1, the switching means 13
Then, the operation of stopping the induction heating of the load 14 for about 2 seconds, and then restarting the driving of the switching means 13a is repeated. Within one minute,
When the characteristic line no longer intersects with the area Y2 by, for example, changing to the load 14 having the characteristic K in FIG.
However, a signal for releasing the second input suppression state 21b is output to the driving unit 16, and the induction heating with a desired input is started.

Here, the second input suppression state 21b differs from the first input suppression state 21a in that the timer means 23 does not count the time during which this operation is performed. By doing so, the load 14 having a characteristic such as the characteristic J can be obtained.
When heating is performed, cooking can be continued without entering the standby mode even after one minute has elapsed, and the first input suppression state 21a and the second input suppression state 21a stored in the first storage unit M3 are stored.
The common operation part of the input suppression state 21b can be shared, and the storage capacity of the first storage unit M3 can be reduced.

Here, the area Y2 includes the area Y1 as shown in FIG. 4 (a). The area Y1 is translated in the positive direction of the horizontal axis by a desired value, and the switching means is switched by a load like the characteristic J. 13a is set so as to include a region where excessive voltage and current are applied and there is no possibility of destruction. This is area Y
By increasing the number of shared portions 1 and Y2, the storage capacity of the second storage means M4 storing the areas Y1 and Y2 can be reduced, and heating can be performed with a load as large as possible even with a load such as the characteristic J. That's why. Further, when the characteristics of the load 14 reach the regions Y1 and Y2 at the same time, it is determined that the region has reached the region Y1, and the first input suppression state 21a is set.

Further, in a state where heating is started with the load 14 having a characteristic such as the characteristic K and the heating is determined as a pot suitable for induction heating, the distance between the heating coil 13b and the load 14 is increased.
The load 1 may be changed because the heating coil 13b and the load 14 are shifted.
When the magnetic coupling between the heating coil 4 and the heating coil 13b becomes small, or when the magnetic characteristics of the load 14 gradually change with the rise of the temperature of the load 14, the input becomes the target of input suppression as a characteristic J. It is determined that the load is a load, and the second input suppression state 21b is set to prevent application of electric / thermal stress to the switching means 13a and the like.

Further, when the characteristic of the input P versus the current I flowing through the heating coil 13b is like the characteristic K in FIG. 4A, the current does not reach either of the areas Y1 and Y2 stored in the second storage means M4. The input suppressing means 21 can output a signal to the driving means 16 and can heat the load 14 with a desired thermal power.

As described above, according to this embodiment, it is possible to determine whether or not the heating is suitable for induction heating based on the characteristics of the input P and the current I flowing through the heating coil 13b at the start of heating, and to notify the user of the heating. Input P vs. heating coil 13 on the way
The current I flowing in b is suitable for induction heating in the case where the characteristic changes due to the above-mentioned cause, but it is unnecessary to determine that the load is inappropriate, and the user is notified that the load is inappropriate for induction heating even though the load is appropriate. Without this, it becomes possible to continue heating the load without applying excessive electric / thermal stress to the switching means 13a and the like.

As in the present embodiment, the second input suppression state 21b is intermittently called heating / non-heating.
3 is not operated to heat the load 14, but the second input suppression state 21b is continuously changed without having a common part of the operation of the first input suppression state 21a and the second input suppression state 21b. Heating at a predetermined input, for example, at an input Pj2 at an operating point J2 that is extremely smaller than the input Pj1 at the operating point J1 in FIG. Needless to say, it's good.

Further, in this embodiment, the inverter circuit 13 is configured to include one switching means. However, it is needless to say that the same effect can be obtained even if the inverter circuit 13 is configured to have two or more switching means. The input suppression unit 21 has two types of input suppression states. However, it is needless to say that the same effect can be obtained and more detailed input suppression can be performed if three or more types of input suppression states are provided. Further, the condition for shifting to each input suppression state is not limited to the condition of the present embodiment, and the current detected by the current detecting means 20 is not limited to the current flowing through the heating coil 13b.

(Embodiment 3) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram showing the configuration of the third embodiment of the present invention, FIG. 6 is a characteristic diagram of the voltage V across the switching means with respect to the input P of the third embodiment of the present invention, and FIG. It is a characteristic diagram of the electric current I which flows into a heating coil with respect to the input P of 3rd Example.

In FIG. 5, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted. Control circuit 1
5 is a driving means 16 for driving the switching means 13a.
An input detecting means 17 for detecting an input to the inverter circuit 13, a voltage detecting means 18 for detecting a voltage between both ends of the switching means 13a, a current detecting means 20 for detecting a high-frequency current flowing through the heating coil 13b, Means 1
A first input suppressing unit 19 for outputting a signal for suppressing the input to the inverter circuit 13 to the driving unit 16 in accordance with the output of the voltage detecting unit 18 with respect to the output of the input unit 7;
7, a second input suppressing means 21 for outputting a signal for suppressing the input to the inverter circuit 13 to the driving means 16 in accordance with the output of the current detecting means 20 with respect to the output of the output 7; And a notifying means 2 comprising a light emitting element or a piezoelectric element for notifying a user of the operation state of the inverter circuit 13 based on the output of the input suppressing means 21 of FIG.
2, timer means 23 for counting the time of the suppression state according to the suppression state outputted by the first input suppression means 19 or the suppression state outputted by the second input suppression means 21; And a driving start means 24 including a switch for outputting a signal for starting the operation of the inverter circuit 13 to the driving means 16.

The first input suppression means 19 includes a first storage means M1 and a second storage means M2. The first storage means M1 stores a first suppression state 19a and a second suppression state 19b in advance. The second storage means M2 stores the first suppressed state 19
The condition for shifting to any one of “a” and the second suppression state 19b is stored in advance. Similarly, the second input suppressing means 21
Storage means M3 and fourth storage means M4, and the third storage means M3 has a third suppressed state 21a and a fourth suppressed state 2
1b is stored in advance, and the fourth storage unit M4 stores in advance a condition for transition to either the third suppression state 21a or the fourth suppression state 21b.

The operation of the above configuration will be described. When the user causes the driving means 16 to output a signal to start driving the switching means 13 a by the driving starting means 24, the driving means 16 switches the switching means 13 a of the inverter circuit 13.
Is turned on and off, the DC power obtained by rectifying the commercial power supply 11 by the rectifier circuit 12 is converted into a high-frequency AC power, a high-frequency current is supplied to the heating coil 13b, and the load 14 such as a pan is induction-heated by the magnetic flux generated from the heating coil 13b. Start. Next, the drive means 16 gradually increases the on-time of the switching means 13a until the input detected by the input detection means 17 reaches a desired input, and changes the high-frequency current supplied to the heating coil 13b to change the heating power of the load 14 Is controlling.

At the same time, the first input suppressing means 19
The input to the inverter circuit 13 detected by the input detecting means 17 and the switching means 13 detected by the voltage detecting means 18
On the basis of the voltage between both ends, the input P and the voltage V between both ends of the switching means 13a which are different depending on the load 14 as shown in FIG. 6A are constantly monitored. This characteristic generally means that the switching means 13 increases as the input P increases.
As the voltage V across the terminal a increases and the magnetic coupling between the heating coil 13b and the load 14 decreases, the increase in the voltage V across the switching means 13a increases even at low input (△).
V / △ P is large).

Similarly, the second input suppressing means 21 generates the signal shown in FIG. 7A based on the input to the inverter circuit 13 detected by the input detecting means 17 and the current flowing through the heating coil 13b detected by the current detecting means 20. ), The characteristics of the input P and the current I flowing through the heating coil 13b which differ depending on the load 14 are constantly monitored. This characteristic is generally
When the magnetic coupling between the heating coil 13b and the load 14 decreases as the current increases, the increase in the current I flowing through the heating coil 13b increases even at a low input (ΔI / ΔP is large).

At this time, the input P versus the switching means 13a
6 is different depending on the load, the input-V voltage characteristic of the switching means 13a is different from that of FIG.
In the case of the characteristics A, B and C of (a), when reaching the area X1 stored in the second storage means M2, the first input suppression means 19 makes the load 14 unsuitable for induction heating. It is determined that the load is a load, the first input suppression state 19a is selected, and a signal for setting the first input suppression state 19a to the driving unit 16 is output. At this time, the first input suppression unit 19 outputs the first input suppression state 19a to the notification unit 22 and the timer unit 23, and the notification unit 22 informs the user that the load 14 is an inappropriate load. Notify and timer means 2
3 starts counting. Here, the region X1 is a characteristic line of a small object such as a knife (characteristic C), a non-load state (characteristic A), and a switching means 1 when heated like an aluminum pan.
An excessive current flows or an excessive voltage is applied to 3a, the loss increases, and there is a possibility that the switching means 13a may be destroyed. Up to the input, it is suitable for induction heating, but if it exceeds this input, an excessive current may flow through the switching means 13a or an excessive voltage may be applied to increase the loss and the switching means 13a may be destroyed by a load which may be destroyed. It is set to include a characteristic line (characteristic D) portion.

Similarly, the input P at this time and the heating coil 13
Since the current I characteristic flowing through the heating coil 13b is different from the characteristic F, G, and H in FIG. 7A, the current I characteristic flowing through the heating coil 13b is different from the fourth storage means M4. Arrives at the area Y1 stored by the controller, the second input suppression means 21 determines that the load 14 is inappropriate for induction heating, selects the third input suppression state 21a, and gives the drive means 16 A signal for setting the third input suppression state 21a is output. At this time, the second input suppression unit 21 outputs the third input suppression state 21a to the notification unit 22 and the timer unit 23, and the notification unit 22 informs the user that the load 14 is an inappropriate load. At the same time, the timer means 23 starts counting. Here, the region Y1 is characterized by a characteristic line (characteristic H) of a small object load such as a knife, an unloaded state (characteristic F), and an excessive current flowing through the switching means 13a or excessive voltage when heated like an aluminum pan. The applied loss may increase and the switching means 13a may be destroyed, and the load characteristic line (characteristic G) which can be clearly determined to be unsuitable for induction heating, or a certain input is suitable for induction heating but exceeds this input And a characteristic line (characteristic J) that may be destroyed by a load in which an excessive current flows or an excessive voltage is applied to the switching means 13a, an excessive loss is applied, and the switching means 13a may be destroyed. I have.

In this embodiment, the first input suppression state 19a
In the case where the driving means 16 starts driving the switching means 13a and gradually increases the ON time, for example, in the case of the load 14 having the characteristic A, the point where the operation line of the characteristic A shown in FIG. In the case of A1, the switching means 13
Then, the operation of stopping the induction heating of the load 14 for about 2 seconds, and then restarting the driving of the switching means 13a is repeated. Further, the timer means 23 counts the time during which this operation is repeated, and
At this time, the operation is stopped and the driving start unit 24 enters a state (called a standby mode) before the driving unit 16 outputs a signal to start driving the switching unit 13a. If the characteristic line no longer intersects with the area X1 within one minute, for example, by changing to the load 14 having the characteristic E in FIG. 6A, the first input suppression unit 19 determines that the load is appropriate. Then, a signal for canceling the first input suppression state 19a is output to the driving means 16 to start induction heating with a desired input, and the timer means 23 clears the time count, and the notification means 22 Stop reporting.

Similarly, in the third input suppression state 21a, the driving means 16 starts driving the switching means 13a and gradually increases the on-time of the switching means 13a.
At the point F1 where the operating line of the characteristic F shown in FIG. 7A and the area Y1 intersect, the driving of the switching means 13a is stopped, the induction heating of the load 14 is stopped for about 2 seconds, and then the switching means 13a is turned on again. The operation of starting driving is repeated. When the timer means 23 counts the time during which this operation is repeated and reaches one minute, the operation is stopped and the drive start means 24 outputs a signal to the drive means 16 to start driving the switching means 13a. (Called a standby mode).
Also, if the area Y1 and the characteristic line no longer intersect within one minute by changing the load 14 to the characteristic K in FIG. 7A, for example,
The second input suppression means 21 determines that the load is appropriate, and
The driving unit 1 outputs a signal for releasing the third input suppression state 21a.
6 to start the induction heating with a desired input, the timer means 23 clears the time count, and the notification by the notification means 22 is stopped.

Such an intermittent heating operation is performed by detecting that an improper load such as a knife is being heated with as little input as possible, and preventing the improper load from becoming high in temperature. The inverter circuit 13 continues to operate with no load and a load 14 that is not suitable for induction heating, and the switching means 1
3a is prevented from being destroyed due to application of excessive electric / thermal stress, and within one minute, an inappropriate load is replaced with a load suitable for induction heating, or the load 14 is changed from a no-load state to a load suitable for induction heating. This is because it is possible to quickly detect the case of changing to the above.

When the voltage characteristic of the input P versus the voltage V across the switching means 13a is like the characteristic D in FIG. 6A, the voltage reaches the area X2 stored in the second storage means M2.
The first input suppression unit 19 selects the second input suppression state 19b and outputs a signal to the driving unit 16 to set the second input suppression state 19b. Similarly, if the characteristic of the input P versus the current I flowing through the heating coil 13b is like the characteristic J in FIG. 7A, the current reaches the area Y2 stored in the fourth storage means M4, and the second input suppression is performed. The means 21 is in the fourth input suppression state 21
b is selected and the driving means 16 is set to the fourth input suppression state 21b.
Output a signal.

In the present embodiment, the second input suppression state 19b
In the case of the load 14 having the characteristic D, for example, when the driving means 16 starts driving the switching means 13a and gradually increases the on-time thereof, for example, the operation line of the characteristic D shown in FIG. At D1, the switching means 13
Then, the operation of stopping the induction heating of the load 14 for about 2 seconds, and then restarting the driving of the switching means 13a is repeated. Within one minute,
When the characteristic line no longer intersects with the region X2 by, for example, changing to the load 14 such as the characteristic E in FIG. 6A, the first input suppression means 19 cancels the second input suppression state 19b. To the driving means 16 to start induction heating with a desired input. Here, the second input suppression state 19b is different from the first input suppression state 19a in that the timer means 23 does not count the time during which this operation is performed. In this way, when the load 14 having the characteristic such as the characteristic D is being heated, cooking can be continued without entering the standby mode even after one minute has elapsed, and the first storage means can be provided. M1
Can share the common operation part of the first input suppression state 19a and the second input suppression state 19b stored by
The storage capacity of the first storage unit M1 can be reduced.

Here, the area X2 includes the area X1 as shown in FIG. 6 (a). The area X1 is translated in the positive direction of the horizontal axis by a desired value, and the switching means is switched by a load like the characteristic D. 13a is set so as to include a region where excessive voltage and current are applied and there is no possibility of destruction. This is area X
By increasing the shared portion of X1 and X2, the storage capacity of the second storage means M2 storing the regions X1 and X2 can be reduced, and heating can be performed with as large an input as possible even under a load such as the characteristic D. That's why. Further, when the characteristics of the load 14 reach the regions X1 and X2 at the same time, it is determined that the load 14 has reached the region X1, and the first input suppression state 19a is set. In addition, in a state where heating is started with the load 14 having the characteristic such as the characteristic E and the heating is determined by determining that the pot is appropriate for induction heating, the heating coil 13b
When the magnetic coupling between the load 14 and the heating coil 13b is reduced due to the distance between the heating coil 13b and the load 14 or the magnetic characteristic of the load 14 increases, the temperature of the load 14 increases. When the load gradually changes together with the load, the load becomes the target load for input suppression as shown by a characteristic D, and the electric / thermal stress is applied to the switching means 13a and the like in the second input suppression state 19b. Is preventing that.

Similarly, in the fourth input suppression state 21b, the driving means 16 starts driving the switching means 13a and gradually increases the on-time of the switching means 13a.
At the point J1 where the operating line of the characteristic J shown in FIG. 7A and the region Y2 intersect, the driving of the switching means 13a is stopped, the induction heating of the load 14 is stopped for about 2 seconds, and then the switching means 13a The operation of starting driving is repeated.

If the characteristic line no longer intersects with the area Y2 within one minute, for example, by changing to the load 14 having the characteristic K in FIG. A signal for canceling the input suppression state 21b is output to the driving means 16 to start induction heating with a desired input. Here, the fourth input suppression state 21b differs from the third input suppression state 21a in that the timer means 23 does not count the time during which this operation is performed. By doing so, when the load 14 having the characteristic such as the characteristic J is being heated, cooking can be continued without entering the standby mode even after one minute has elapsed, and the third storage means. The third that M3 remembers
The common operation part of the input suppression state 21a and the fourth input suppression state 21b can be shared, and the third storage unit M3
Storage capacity can be saved. This operation is performed in the first input suppression state 19a and the second input suppression state 19a.
The storage capacity is prevented from increasing by sharing with the common operation part b.

The area Y2 includes the area Y1 as shown in FIG. 7A. The area Y1 is translated in the positive direction of the horizontal axis by a desired value, and the switching means is switched by a load like the characteristic J. 13a is set so as to include a region where excessive voltage and current are applied and there is no possibility of destruction. This is area Y
By increasing the number of shared portions 1 and Y2, the storage capacity of the fourth storage means M4 storing the areas Y1 and Y2 can be reduced, and heating can be performed with as large an input as possible even under a load such as the characteristic J. That's why. Further, when the characteristics of the load 14 reach the regions Y1 and Y2 at the same time, it is determined that the region has reached the region Y1, and the state becomes the third input suppression state 21a. In addition, in a state where heating is started with the load 14 having a characteristic such as the characteristic K, the heating is determined to be a pan suitable for induction heating, and the heating coil 13b
When the magnetic coupling between the load 14 and the heating coil 13b is reduced due to the distance between the heating coil 13b and the load 14 or the magnetic characteristic of the load 14 increases, the temperature of the load 14 increases. In the case where the load gradually changes together with the load, it is determined that the load is the target of input suppression as shown by the characteristic J, and the fourth input suppression state 21b is set, and electric / thermal stress is applied to the switching means 13a and the like. Is prevented from being done.

In the case where the voltage characteristic between the input P and the voltage V across the switching means 13a is like the characteristic E in FIG.
Does not reach any of the regions X1 and X2 stored in the storage means M2, the first input suppression means 19 does not output any signal to the drive means 16 and can heat the load 14 with a desired heating power. Similarly, when the characteristic of the input P versus the current I flowing through the heating coil 13b is like the characteristic K in FIG. 7A, the current I does not reach either of the areas Y1 and Y2 stored in the fourth storage means M4. The second input suppressing means 21 can output a signal to the driving means 16 and can heat the load 14 with a desired thermal power.

Further, the input P versus the voltage V characteristic across the switching means 13a is the T characteristic shown in FIG.
The load 14 in which the current I characteristic flowing through the heating coil 13b is the U characteristic shown in FIG. 7A is heated without suppressing the input, and the input P versus the voltage V characteristic across the switching means 13a is shown in FIG. 6A, when the load 14 of the E characteristic wants to suppress the input, the load 14 whose input-V voltage characteristic of the switching means 13a is the E characteristic of FIG. 6A flows to the input P-heating coil 13b. FIG. 7A shows the current I characteristic.
In the case of the H characteristic described above, the first input suppression means 19 determines that the load is appropriate despite the improper load, but the second input suppression means 21 determines that the load is inappropriate. ,
The third input suppression state 21a can be set. vice versa,
The input V vs. the voltage V characteristic between both ends of the switching means 13a is the T characteristic shown in FIG.
7A is heated without suppressing the input, and the current I characteristic flowing to the input P versus the heating coil 13b is changed to the K characteristic in FIG. 7A. When it is desired to suppress the input of the load 14 having the characteristic, for example, the characteristic of the input I versus the current I flowing through the heating coil 13b is represented by K in FIG.
When the load 14 having the characteristic has the input P versus the voltage V characteristic between both terminals of the switching means 13a is the C characteristic shown in FIG. 6A, the second input suppressing means 21 is appropriate even though it is an inappropriate load. Although the load is determined, the first input suppression unit 19 determines that the load is inappropriate and the first input suppression state 19.
a.

As described above, according to the present embodiment, whether heating is suitable for induction heating is determined based on the characteristics of the input P versus the voltage V across the switching means 13a or the characteristics of the input P versus the current I flowing through the heating coil 13b at the start of heating. In addition to being able to discriminate and inform the user, the input P versus the voltage V characteristic between both ends of the switching means 13a or the input P versus the heating coil
3b is suitable for induction heating when the characteristic of the current I flowing through 3b changes due to the above-mentioned cause, etc., but it is not necessary to determine that the load is inappropriate, and the user is notified that the load is inappropriate for induction heating even though the load is appropriate. Without this, it becomes possible to continue heating the load without applying excessive electric / thermal stress to the switching means 13a and the like, and even if one of the input suppression means cannot determine that the load is inappropriate. On the other hand, if the other input suppression means can determine that the load is inappropriate, the desired input suppression state can be set, so that the input can be more finely suppressed for the desired load.

As in the present embodiment, the second input suppression state 19b is intermittently called heating / non-heating.
3, the load 14 is not heated to heat the load 14. Instead, the operations of the first input suppression state 19a and the second input suppression state 19b are not shared and the second input suppression state 19b is continuously switched to a predetermined input. For example, the input Pd1 at the operating point D1 in FIG.
Needless to say, a method of maintaining the input Pd2 at the smaller operating point D2 and heating with an almost maximum input that can be heated with the load of the characteristic D may be used. Similarly, instead of heating the load 14 by operating the inverter circuit 13 intermittently in which the fourth input suppression state 21b is referred to as heating / non-heating as in the present embodiment, the third input suppression state 21a 4th
The fourth input suppression state 21b is continuously switched to a predetermined input, for example, an operation point J2 which is extremely smaller than the input Pj1 at the operation point J1 of FIG. 7A without having a common part of the operation of the input suppression state 21b. It is needless to say that a method of heating with almost the maximum input that can be heated with the load of the characteristic J while maintaining the input Pj2 at the above is also possible.

Further, in the present embodiment, the inverter circuit 13 is configured to include one switching means, but it is needless to say that the same effect can be obtained even if the inverter circuit 13 is configured to have two or more switching means. Then, the first input suppressing means 1
9 and the second input suppression means 21 change the input suppression state to 2
Although it is assumed that a plurality of types are provided, it is needless to say that the same effect can be obtained and more detailed input suppression can be performed even if three or more types are provided. Further, the condition for shifting to each input suppression state is not limited to the condition of the present embodiment, the voltage detected by the voltage detecting means 18 is not limited to the voltage across the switching means 13a, and the current detected by the current detecting means 20 is heated. The current is not limited to the current flowing through the coil 13b.

[0079]

As described above, according to the first aspect of the present invention, the input detecting means detects an input to the inverter circuit, and the voltage detecting means detects a high-frequency voltage value generated by the inverter circuit. Further, since the characteristic of the output of the voltage detection means with respect to the output of the input detection means differs depending on the load, the input suppression means can detect the operation state of the inverter circuit according to the output of the voltage detection means with respect to the output of the input detection means. It is possible to determine whether or not the load to be heated is suitable for induction heating, or whether or not heating may be performed. Therefore, the control circuit can output a control signal based on the judgment of the input suppression means to the inverter circuit, and can suppress the input of the inverter circuit.

Further, the input suppression means has at least two or more types of input suppression states.
A desired input suppression state can be selected from a plurality of input suppression states according to the characteristics of the output of the voltage detection means with respect to the output of the input detection means, and the input can be finely suppressed for a desired load.

According to the second aspect of the present invention, the input detecting means detects an input to the inverter circuit, the current detecting means detects a value of a current flowing through the inverter circuit, and detects an output of the input detecting means. Since the characteristics of the output of the current detection means differ depending on the load, the input suppression means can detect the operation state of the inverter circuit in accordance with the output of the current detection means with respect to the output of the input detection means, and the load to be heated can be induced. It is possible to determine whether or not heating is suitable, or whether or not heating may be performed. Therefore, the control circuit can output a control signal based on the judgment of the input suppression means to the inverter circuit, and can suppress the input of the inverter circuit.

Further, since the input suppression means has at least two or more types of input suppression states, it differs depending on the load.
A desired input suppression state can be selected from a plurality of input suppression states according to the characteristics of the output of the current detection means with respect to the output of the input detection means, and the input can be finely suppressed for a desired load.

According to the third aspect of the invention, the input detecting means detects an input to the inverter circuit, the voltage detecting means detects a high-frequency voltage value generated by the inverter circuit, and Since the characteristics of the output of the voltage detection means with respect to the output differ depending on the load, the first input suppression means can detect the operation state of the inverter circuit according to the output of the voltage detection means with respect to the output of the input detection means. Whether the load to be heated is suitable for induction heating,
Alternatively, it is possible to determine whether or not heating can be performed. Therefore, in the control circuit, the first input suppressing unit can output a control signal based on the determination to the inverter circuit, and can suppress the input of the inverter circuit.

Similarly, the current detecting means detects the value of the current flowing through the inverter circuit, and the characteristic of the output of the current detecting means with respect to the output of the input detecting means differs depending on the load.
The second input suppression means can detect the operation state of the inverter circuit in accordance with the output of the current detection means with respect to the output of the input detection means, and determine whether the load to be heated is suitable for induction heating, or It is possible to determine whether or not it is OK. Therefore, the control circuit can output a control signal based on the judgment of the second input suppressing means to the inverter circuit, and can suppress the input of the inverter circuit.

Further, since the first and second input suppression means each have an input suppression state, it is desired to individually heat a plurality of loads having different characteristics and to suppress the input to a desired load among them. In the case, even if one of the characteristics of the output of the voltage detection means or the output of the current detection means with respect to the output of the input detection means does not have a difference in the characteristics and the input cannot be suppressed only to a desired load, the other side has the characteristics. If there is a difference, the first or the second that can detect the difference in the characteristics
The input can be suppressed by the input suppression means, so that the input can be more finely suppressed for a desired load.

According to a fourth aspect of the present invention, in the third aspect of the invention, at least one of the first and second input suppression means has at least two types of input suppression states. , Since at least one of the first and second input suppression means has at least two or more types of input suppression states, when individually heating a plurality of loads having different characteristics, voltage detection for the output of the input detection means is performed. Either of the means or the characteristics of the output of the current sensing means
Even if the characteristics cannot be changed to a different input suppression state because there is no difference in the characteristics, if there is a difference in the characteristics on the other hand, the first or second input suppression limit means capable of detecting the difference in the characteristics has two
Since more than one kind of input suppression state can be set, a desired input suppression can be performed from a plurality of input suppression states according to the characteristics of the output of the voltage detection means or the current detection means with respect to the output of the input detection means, which differ depending on the load. Set the state,
Different input suppression states can be set, and input can be more finely suppressed for a desired load.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the control circuit has a notifying means, and the notifying means includes a plurality of input suppression states provided in the input suppression means. In response to the above, at least one or more notifications are configured to be provided, and in accordance with the input suppression state set by the input suppression means, the notification means sets at least one or more of the desired input suppression states Since the notification can be performed, the user can recognize what kind of input suppression state the user is currently in.

According to a sixth aspect of the present invention, in the first to fifth aspects, the control means has a timer means, and the input suppression means suppresses an input of the inverter circuit. Wherein the timer means is a first
Is counted, and the operation of the inverter circuit is shifted to a predetermined operation mode based on the count result. If the first suppression state is canceled or the second input suppression state is entered, the timer means is activated. The counting is stopped or the counted time is cleared. Since the timer means can count the time in the first input suppression state, the input suppression means changes the operation mode of the inverter circuit based on the count result. It is possible to change. Also, the first suppression state is released or the second suppression state is released.
In the suppression state, the time counted by the counting means is suspended or cleared.
If the input suppression means shifts to the suppression state, the input suppression means does not change the operation mode of the inverter circuit, so that it is determined that the input suppression means is inappropriate for induction heating despite the load suitable for induction heating. Thus, the operation mode of the inverter circuit can be kept unchanged, and the load can be heated in the second input suppression state or a predetermined input.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an induction heating cooker according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of a voltage between both ends of a switching means with respect to an input of the induction heating cooker.

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

FIG. 4 is a characteristic diagram of a current flowing through a heating coil with respect to an input of the induction heating cooker.

FIG. 5 is a block diagram showing a configuration of an induction heating cooker according to a third embodiment of the present invention.

FIG. 6 is a characteristic diagram of the voltage between both ends of the switching means with respect to the input of the induction heating cooker.

FIG. 7 is a characteristic diagram of a current flowing through a heating coil with respect to an input of the induction heating cooker.

[Explanation of symbols]

 Reference Signs List 13 inverter circuit 13a switching means 13b heating coil 15 control circuit 17 input detection means 18 voltage detection means 19 (first) input suppression means 19a first input suppression state 19b second input suppression state 20 current detection means 21 (first 2) input suppression means 21a first (third) input suppression state 21b second (fourth) input suppression state 22 notification means 23 timer means

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akihisa Nakano 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. An inverter circuit for supplying a high-frequency current to a heating coil, and a control circuit for controlling the operation of the inverter circuit, wherein the control circuit detects input current of the inverter circuit, A voltage detecting means for detecting a voltage between both ends of the switching means used in the inverter circuit; and an input suppressing means for suppressing an input of the inverter circuit in accordance with an output of the voltage detecting means with respect to an output of the input detecting means. An induction heating cooker comprising at least two types of input suppression states by the input suppression means. 2. An inverter circuit for supplying a high-frequency alternating current to a heating coil, and a control circuit for controlling operation of the inverter circuit, wherein the control circuit detects input current of the inverter circuit, A current detection unit that detects a current flowing in the inverter circuit; and an input suppression unit that suppresses an input of the inverter circuit in accordance with an output of the current detection unit with respect to an output of the input detection unit. An induction heating cooker comprising at least two types of input suppression states by means. 3. An inverter circuit for supplying a high-frequency current to a heating coil, and a control circuit for controlling an operation of the inverter circuit, wherein the control circuit detects an input current of the inverter circuit, Voltage detection means for detecting a high-frequency voltage generated in the inverter circuit,
Current detection means for detecting a current flowing in the inverter circuit; first input suppression means for suppressing an input of the inverter circuit in response to an output of the voltage detection means with respect to an output of the input detection means; An induction heating cooker comprising: a second input suppression unit that suppresses an input of the inverter circuit in accordance with an output of the current detection unit with respect to an output of the detection unit. 4. The induction heating cooker according to claim 3, wherein at least one of the input suppression means has at least two kinds of input suppression states. 5. The guidance according to claim 1, further comprising a notification unit, wherein the notification unit has different notification states according to a plurality of input suppression states of the input suppression unit. Cooking cooker. 6. In a state in which the input means suppresses the input of the inverter circuit, the timer means counts the time during which the input means is in the first input suppression state. 2. The method according to claim 1, wherein the operation of the inverter circuit is shifted to a predetermined operation mode, and when the first suppression state is released or the second suppression state is entered, the timer means stops counting or clears the counted time. 6. The induction heating cooker according to any one of claims 1 to 5.