JP6827163B2 - Induction heating cooker - Google Patents

Description

The present invention relates to an induction heating cooker used in a kitchen of a general household or the like.

Conventionally, as an induction heating cooker of this kind, for example, there is one described in Patent Document 1. Patent Document 1 describes a plurality of heating coils, an inverter circuit for inductively heating an object to be heated, an input current detecting means, a switching voltage detecting means, and an inverter, and in the case of a plurality of simultaneous heating, an inverter at the same frequency. The control means is provided with a control means for suppressing the interference sound of the heated body, and the control means has a pot type determination means, and when the heating coil is operated first, the switching voltage is set with respect to the input current. Inductive heating is performed so as to obtain the rated input power without switching the drive frequency of the inverter circuit in the region where the value is equal to or less than the predetermined value, and the switching voltage becomes higher than the predetermined value with respect to the input current and the drive frequency is used as it is. When the voltage of the switching means is large and the switching element has the potential to be destroyed, the drive is lowered to the optimum drive frequency of the first operated heating coil to obtain the rated input power. When the heating coil is operated by performing frequency switching operation for induction heating and operating the second and subsequent heating coils at the same time, the driving frequency of the heating coil operated after the second is set to the first operating frequency of the heating coil. An inductive heating device that is adjusted to the optimum drive frequency is described, and the drive frequency of the inverter circuit is optimized for the object to be heated, and the maximum input power is obtained to give the user a feeling of thermal power. It is possible to suppress the electric current of the switching means and the electric current of the inverter circuit components, and to suppress the pan noise caused by the difference in the drive frequencies of a plurality of coils.

Japanese Patent No. 4325446

However, in the conventional configuration, once the drive frequency is lowered to the optimum drive frequency, the drive frequency is always fixed to the drive frequency approaching the audible region while the heating is continued, so that the user can hear the sound of the drive frequency. There was a problem that there was a risk and the possibility of discomfort increased.

The present invention solves the above-mentioned conventional problems, and suppresses the pan noise generated by the difference in the drive frequencies of a plurality of coils while reducing the risk of the user hearing the sound of the drive frequency, and guides the user to use it easily. The purpose is to provide a cooker.

In order to solve the above-mentioned conventional problems, the induction heating cooker of the present invention has a top plate on which the heated body is placed and a plurality of the induction heating cookers arranged below the top plate to heat the heated body. A heating coil, an inverter circuit that is provided corresponding to the plurality of heating coils and supplies a high-frequency current to the heating coil, a control unit that controls the operation of the inverter circuit, and an operation for selecting an operating state. The inverter circuit includes a display unit, the inverter circuit is provided with a switching means for switching the current of the resonance circuit, and the control unit indicates whether or not the heated body is placed above the heating coil. A unit to be heated for determination and a conduction time detection unit for detecting the conduction time of the switching means are provided. And the second heating coil is selected, and when the first heating coil and the second heating coil on which the heated body is placed are operated at the same time to heat the heated body, the said When the first heating coil and the second heating coil are separated by a first predetermined distance or more and the conduction time is equal to or less than a predetermined value, the drive frequency of the inverter circuit is set to a predetermined value. The corresponding heating coil is operated at the predetermined frequency without switching from the frequency to induce and heat the object to be heated, and the distance between the first heating coil and the second heating coil is equal to or greater than the first predetermined distance. When they are separated and the conduction time is longer than the predetermined value, the drive frequency of the inverter circuit detected that the conduction time is longer than the predetermined value is lowered from the predetermined frequency, and the corresponding heating coil is used. Is operated to induce and heat the object to be heated. Further, in the induction heating cooker, a first heating area and a second heating area on which the heated body is placed are provided on the top plate. In the first heating area, three or more circular or elliptical heating coils are arranged in parallel in the front-rear direction or the left-right direction. In the second heating area, the diameter is formed to be larger than the minor axis or the diameter of the one heating coil constituting the first heating area.
In the first heating area, the operation display unit is operated in the control unit, the first heating area is selected, and the heated body is placed above the heating coil.
The number of the heating coils for heating the object to be heated is switched according to the number of the heating coils operated at the same time. When the control unit operates a plurality of the heating coils continuously arranged in the first heating area at the same time, the control unit drives the inverter circuit at the same frequency, and the second heating area and the first heating area. Depending on the distance between the first heating coil arranged in the first heating area and the second heating coil arranged in the second heating area when simultaneously heating in the heating area of The drive frequency of the inverter circuit is determined.

With this configuration, it is possible to provide a user-friendly induction heating cooker by suppressing the pan noise caused by the difference in the driving frequencies of a plurality of coils while reducing the possibility that the user hears the sound of the driving frequency.

The induction heating cooker of the present invention suppresses the pan noise caused by the difference in driving frequencies of a plurality of coils while reducing the risk of the user hearing the sound of the driving frequency, and provides the user with an easy-to-use induction heating cooker. can do. In addition, the position of the object to be heated can be changed in the first heating area to heat the body, which can improve usability and effectively utilize the limited space. Further, it is possible to suppress the pan noise generated by the difference in the drive frequencies of the plurality of coils in the first heating area and the first area and the second area, and it is possible to improve the usability.

Overall configuration diagram of the induction cooking device according to the first and second embodiments of the present invention. The figure seen from the upper surface of the induction heating cooker in Embodiments 3 and 4 of this invention. Circuit diagram of a switching means for switching the heating coil in the first heating area of the induction heating cooker according to the third and fourth embodiments of the present invention.

The first invention corresponds to a top plate on which a heated body is placed, a plurality of heating coils that are arranged below the top plate and heat the heated body, and a plurality of the heating coils. The inverter circuit is provided with a plurality of inverter circuits for supplying a high-frequency current to the heating coil, a control unit for controlling the operation of the inverter circuit, and an operation display unit for selecting an operating state. Is provided with a switching means for switching the current of the resonance circuit, and the control unit includes a heated body detecting unit for determining whether or not the heated body is mounted above the heating coil, and the switching. A conduction time detecting unit for detecting the conduction time of the means is provided, and the operation display unit is operated in the control unit, and a first heating coil and a second heating coil are selected from the heating coil. When the first heating coil and the second heating coil on which the heated body is placed are operated at the same time to heat the heated body, the first heating coil and the second heating coil are heated. When the coil is separated from the coil by a first predetermined distance or more and the conduction time is equal to or less than a predetermined value, the corresponding frequency corresponds to the predetermined frequency without switching the drive frequency of the switching means of the inverter circuit. The heating coil is operated to induce and heat the object to be heated, and the first heating coil and the second heating coil are separated by a first predetermined distance or more and the conduction time is greater than the predetermined value. When it becomes longer, the drive frequency of the inverter circuit detected that the conduction time is longer than the predetermined value is lowered from the predetermined frequency, and the corresponding heating coil is operated to induce and heat the heated body. It is a thing. As a result, it is possible to reduce the risk that the user will hear the sound of the drive frequency and suppress the pan noise caused by the difference in the drive frequencies of the plurality of coils, and it is possible to improve the usability.

In the second invention, particularly in the first invention, the operation display unit is operated in the control unit, and the first heating coil and the second heating coil are selected from the heating coil. When the first heating coil and the second heating coil on which the heating body is placed are operated at the same time to heat the heated body, the first heating coil and the second heating coil When the distance is a second predetermined distance closer than the first predetermined distance, the inverter circuit is driven at the same frequency. As a result, even when the distance between the heating coils is short, it is possible to reduce the risk that the user will hear the sound of the drive frequency and suppress the pan noise caused by the difference in the drive frequencies of multiple coils, which improves usability. Is possible.

In the third invention, in particular, in the first or second invention, the first heating area and the second heating area on which the heated body is placed are provided on the top plate, and the first In the heating area of 1, three or more of the circular or elliptical heating coils are arranged in parallel in the front-rear direction or the left-right direction, and in the second heating area, the first heating area is formed. It is formed so as to have a diameter larger than the minor axis or the diameter of one heating coil, and in the first heating area, the control unit operates the operation display unit, and the first heating area is selected. The heated body is placed on the upper side and operates simultaneously according to the number of the heated coils to switch the number of the heated coils for heating the heated body, and the control unit uses the first control unit. When a plurality of the heating coils arranged continuously in the heating area are operated at the same time, the inverter circuit is driven at the same frequency, and the second heating area and the first heating area are simultaneously heated. The drive frequency of the inverter circuit is determined according to the distance between the first heating coil and the second heating coil. As a result, the heated body can be heated by changing the position in the first heating area, the usability can be improved, and the limited space can be effectively utilized. Further, it is possible to suppress the pan noise generated by the difference in the drive frequencies of the plurality of coils in the first heating area and the first area and the second area, and it is possible to improve the usability.

The fourth invention is a configuration in which, in particular, in the third invention, the second heating area is provided on either or both of the left and right sides of the first heating area. As a result, the user can use both the first and second heating areas at a position close to the front of the product, and the usability can be further improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

(Embodiment 1)
FIG. 1 is an overall configuration diagram of the induction cooking device according to the first and second embodiments of the present invention.

In FIG. 1, a rectifier circuit composed of a diode bridge that converts an AC voltage from an AC power supply into a DC voltage is connected to a smoothing circuit composed of a choke coil and a smoothing capacitor.
Further, on the output side of the smoothing circuit, a series connector of a first switching element (IGBT) and a second switching element (IGBT) including a reverse conduction diode inside is connected.
A resonance circuit is formed between the connection point between the first switching element and the second switching element and the low potential side or high potential side of the smoothing capacitor with the heating coil 3 and the heating coil 3 for inducing and heating the object to be heated 1. Resonant capacitors are connected in series.

A top plate 2 which is an insulator and is made of heat-resistant glass is provided on the upper part of the heating coil 3, and the heated body 1 is placed so as to face the heating coil 3 with the top plate 2 sandwiched between them. ..

The heating coil 3a and the heating coil 3b are installed at a first predetermined distance (for example, 4 cm). As shown in FIG. 2, the distance between the first heating coil and the second heating coil referred to here is the closest distance X between the outer circumference of the first heating coil and the outer circumference of the second heating coil. Is.

The inverter circuit 4 supplies a high-frequency resonance current to the heating coil 3, and is composed of a first switching element, a second switching element, a heating coil 3, and a resonance capacitor.

The control unit 5 exclusively alternately conducts the first switching element and the second switching element at a constant frequency by a signal transmitted from the operation display unit, and controls the output of the inverter circuit 4 to start heating the device. And stop.

The operation display unit displays information recognized by the device to the user or prompts the user to operate the device by using a signal transmitted from the control unit 5.

Further, a resonance voltage detection unit that detects the resonance voltage of the inverter circuit 4 is provided, and the heated body detection that determines whether or not the heated body 1 is mounted based on the detection values of the input current detection unit and the resonance voltage detection unit. There is a part. Since the impedance of the heating coil 3 changes depending on the presence / absence and size of the heated body 1 placed above the heating coil 3, the amount of current flowing through the inverter circuit 4 also changes accordingly, and resonance occurs. The voltage also changes. The on-time of the switching element is controlled so that the detection current of the input current detection unit becomes a predetermined value. As the on-time of the switching element increases, the current flowing through the heating coil 3 increases, and the resonance voltage due to the heating coil 3 and the resonance capacitor increases. A detection current is passed through each heating coil 3, and whether or not the heated body 1 is located above the heating coil 3 as compared with the threshold value set by the heated body detection unit based on the change in the detected value due to this. It is configured to output a detection signal to the control unit 5 when it is determined that the heated body 1 is arranged at an upper position in the heating coil 3. In the present embodiment, the detection is performed by the resonance voltage, but there is also a method of detecting the coil current, and the detection method is not limited.

The operation and operation of the induction cooking device configured as described above will be described below.

First, when the power switch of the induction heating cooker is pressed, the AC power supply is converted to the DC power supply by the rectifier circuit. In this state, there is no signal for driving the switching element, and the heated body 1 is not heated.

Next, when the heating on / off key of the operation display unit is pressed, the heated body detection unit determines whether or not the heated body 1 is mounted above the heating coil 3, and the mounted body 1 is determined to be mounted. When the determination is made, the control unit 5 heats the heated body 1 so as to have the thermal power displayed on the operation display unit. When it is determined that the heated body 1 is not mounted, the information that the heated body 1 is not mounted is displayed on the operation display unit, and the heated body 1 is not heated (for example, "-" is displayed). .. At this time, the heated body detection unit makes a determination at a fixed cycle (for example, a 2-second cycle), and when the heated body 1 is placed in the middle, heating can be performed immediately. Further, if the state of not being placed for a certain period of time (for example, 1 minute) continues, it is determined that there is no intention of heating, and the state returns to the state in which the power switch is pressed.

When heating multiple burners, press the corresponding heating on / off key on the operation display.

Next, the operation of the control unit 5 will be described. The control unit 5 has a conduction time detection unit 6 that detects the conduction time of the switching element (IGBT), and when the conduction time is equal to or less than a predetermined value (for example, 32 μs), the drive frequency is not switched (for example, 23 kHz, When the period is 43.4 μs) induction heating, the thermal power becomes large, and the conduction time becomes longer than the predetermined value, the drive frequency of the burner inverter circuit 4 corresponding to the conduction time becoming longer than the predetermined value is lowered. hand(
For example, 20.8 kHz, period is 48 μs) induction heating. Further, by taking a first predetermined distance (for example, 4 cm) between the heating coil 3a and the heating coil 3b, the magnetic fluxes from the plurality of heating coils 3 do not enter into one heated body 1.

With the above configuration, it is possible to reduce the possibility that the user hears the sound of the drive frequency and suppress the pan noise caused by the difference in the drive frequencies of the plurality of coils, and it is possible to improve the usability.

(Embodiment 2)
Next, the cooking device according to the second embodiment of the present invention will be described.

Parts having the same function and the same configuration as in the first embodiment are assigned the same numbers, the description thereof will be omitted, and only the differences will be described.

The difference from the first embodiment is that when the heating coils are replaced with a plurality of heating coils separated by a second predetermined distance in which the distance between the heating coils is closer than the first predetermined distance, the control unit 5 is used. The point is that the inverter is driven at the same frequency when a plurality of adjacent heating coils 3 are heated at the same time.

By setting the second predetermined distance (for example, 2 cm) closer than the first predetermined distance (for example, 4 cm), magnetic fluxes from the plurality of heating coils 3 enter into one object to be heated, so that a plurality of adjacent heating bodies are heated. When the coils 3 are heated at the same time, the drive frequencies of all the corresponding inverter circuits 4 are the same (for example, 23 kHz), and when the magnetic fluxes from the plurality of heating coils 3 do not enter into one heated body 1, as described above. When the conduction time is higher than the predetermined value, the drive frequency of the inverter circuit 4 of the corresponding burner is lowered (for example, 20.8 kHz) for induction heating. Since the total power is regulated during simultaneous heating (prevention of breaker interruption), the power output by one inverter circuit 4 is also lower than that during single heating, so the desired power should be supplied without lowering the drive frequency. Is possible. Further, since the interference sound of the heated body is generated by the magnetic fluxes of different frequency bands entering the one heated body 1 from the plurality of heating coils 3, the drive frequency is the same in the simultaneous heating when not applicable. There is no need to.

With the above configuration, it is possible to reduce the possibility that the user hears the sound of the drive frequency and suppress the pan noise caused by the difference in the drive frequencies of the plurality of coils, and it is possible to improve the usability.

(Embodiment 3)
Next, the cooking device according to the third embodiment of the present invention will be described.

Parts having the same functions and configurations as those of the first and second embodiments are assigned the same numbers, the description thereof will be omitted, and only the differences will be described. FIG. 2 is a view seen from the upper surface of the cooking utensil according to the third and fourth embodiments of the present invention. FIG. 3 is a circuit diagram of a switching means for switching the heating coil in the first heating area of the induction heating cooker according to the third and fourth embodiments of the present invention.

The difference from the first and second embodiments is that the first heating area 2-1 and the second heating area 2-2 on which the object to be heated 1 is placed are provided on the top plate 2, and the first heating area 2 is provided. The heating coil 3-1 of -1 is configured by arranging three or more circular or elliptical heating coils in parallel in the front-rear and left-right directions, and the heating coil 3-2 of the second heating area 2-2 is It is assumed that the diameter is larger than the minor axis or the diameter of one heating coil 3-1 constituting the first heating area 2-1. In the first heating area 2-1 according to the object to be heated 1. The point is that the number of heating coils to be heated is switched.

As shown in FIG. 3, in the first heating area 2-1 the contact of the switching means 7 for switching the connection of the plurality of heating coils 3-1 directly under the first heating area, for example, the contact of the relay, is controlled by the control unit 5. Can control and switch the number of heating coils 3-1 according to the heated body 1 placed on the top plate 2, so that, for example, the right side of the four elliptical heating coils 3-1 arranged side by side. When the heated body 1 is placed across two pieces and heated, the two heating coils 3-1 on the right side heat the body, and the remaining two heating coils 3-1 on the left side have high frequencies. Does not supply current. In addition, when the heated body 1 is placed over the two centers of the four elliptical heating coils 3-1 and the heating operation is performed, the heating is performed by the two center heating coils 3-1. This is done, and no high frequency current is supplied to the remaining heating coils 3-1. The same applies when placed on the left two. Further, when the heated body 1 is placed over all four of the four elliptical heating coils 3-1 arranged side by side and the heating operation is performed, the heating is performed by all the four heating coils 3-1. Do. In addition, when the heated body 1 is placed on the right three of the four elliptical heating coils 3-1 and the heating operation is performed, the heating is performed by the three heating coils 3-1 on the right. Do. The same applies when the heated body 1 is placed on the three coils on the left. Further, when the heated body 1 is placed on one coil of four elliptical heating coils 3-1 and the heating operation is performed, heating is performed only by this one heating coil.

As a result, it is possible to select and heat three positions in the first heating area 2-1 such as left and right, and the induction heating cooker used by incorporating it in a cabinet such as a kitchen can be installed. And the size of the top plate is limited, but within this limitation, the inside of the top plate 2 can be effectively used.

With the above configuration, the position of the object to be heated 1 can be changed and heated in the first heating area 2-1 to improve usability and effectively utilize the limited space. It will be possible.

As described in the first and second embodiments, the distance between the two heating coils that are operated simultaneously in the first heating area and / and the second heating area, for example, the first. By determining the drive frequency of the inverter circuit corresponding to each heating coil by a predetermined distance or a second predetermined distance closer than the first predetermined distance, the pan noise generated by the difference in the drive frequencies of a plurality of coils is suppressed. be able to.

(Embodiment 4)
Parts having the same functions and configurations as those in the first to third embodiments are assigned the same numbers, the description thereof will be omitted, and only the differences will be described.

The difference from the first to third embodiments is that the second heating area 2-2 is provided on either or both of the left and right sides of the first heating area 2-1.

With the above configuration, the user can use both the first and second heating areas 2-1 and 2-2 at a position close to the front of the product, and the usability can be further improved.

As described above, the induction cooking cooker according to the present invention can suppress the pan noise caused by the difference in the driving frequencies of a plurality of coils while reducing the risk of the user hearing the sound of the driving frequency. The same can be applied to other cookers used in home kitchens and commercial kitchens.

1 Heated body 2 Top plate 2-1 First heating area 2-2 Second heating area 3 Heating coil 3a Heating coil 3b Heating coil 3-1 Heating coil directly under the first heating area 3-2 Second Heating coil directly under the heating area 4 Inverter circuit 5 Control unit 6 Conduction time detection unit 7 Switching means

Claims (3)

A top plate on which the heated body is placed, a plurality of heating coils arranged below the top plate, and a plurality of heating coils for heating the heated body, and a plurality of heating coils are provided corresponding to the heating coils. It includes an inverter circuit that supplies a high-frequency current to the heating coil, a control unit that controls the operation of the inverter circuit, and an operation display unit that selects an operating state.
The inverter circuit is provided with a switching means for switching the current of the resonant circuit.
The control unit includes a heated body detecting unit that determines whether or not the heated body is placed above the heating coil, and a conduction time detecting unit that detects the conduction time of the switching means. Be,
In the control unit, the operation display unit is operated, and the first heating coil and the second heating coil are selected from the heating coils.
In the case where the first heating coil and the second heating coil on which the heated body is placed are operated at the same time to heat the heated body.
When the first heating coil and the second heating coil are separated by a first predetermined distance or more and the conduction time is equal to or less than a predetermined value,
Without switching the drive frequency of the inverter circuit from a predetermined frequency, the corresponding heating coil is operated at the predetermined frequency to induce and heat the heated body.
When the first heating coil and the second heating coil are separated by a first predetermined distance or more and the conduction time is longer than the predetermined value, the conduction time is longer than the predetermined value. An induction heating cooker that lowers the drive frequency of the inverter circuit detected to be long from the predetermined frequency and operates the corresponding heating coil to induce and heat the object to be heated .
A first heating area and a second heating area on which the heated body is placed are provided on the top plate.
In the first heating area, three or more circular or elliptical heating coils are arranged in parallel in the front-rear direction or the left-right direction.
In the second heating area, the diameter is formed to be larger than the minor axis or the diameter of the one heating coil constituting the first heating area.
In the first heating area
In the control unit, the operation display unit is operated and the first heating area is selected.
The heated body is placed on the upper side and operates simultaneously according to the number of the heating coils to switch the number of the heating coils for heating the heated body.
When the plurality of heating coils arranged continuously in the first heating area are operated at the same time, the control unit drives the inverter circuit at the same frequency.
When heating in the second heating area and the first heating area at the same time,
The drive frequency of the inverter circuit is determined according to the distance between the first heating coil arranged in the first heating area and the second heating coil arranged in the second heating area. , Induction heating cooker. In the control unit, the operation display unit is operated, and the first heating coil and the second heating coil are selected from the heating coils.
In the case where the first heating coil and the second heating coil on which the heated body is placed are operated at the same time to heat the heated body.
When the first heating coil and the second heating coil are separated by a second predetermined distance closer than the first predetermined distance, the first heating coil and the second heating coil are separated from each other by a second predetermined distance.
The induction heating cooker according to claim 1, wherein the inverter circuit is driven at the same frequency. The induction heating cooker according to claim 1 or 2 , wherein the second heating area is provided on either one or both of the left and right sides of the first heating area.

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