KR102492942B1 - Induction heating device capable of sensing vibration of the heated body - Google Patents

Abstract

The present invention relates to an induction heating device capable of sensing vibration of a heating target by detecting a resonant frequency between a heating coil and a knob switch. An induction heating device according to an embodiment of the present invention includes a heating coil provided on a main body to generate a magnetic field, a resonant coil provided on an upper surface of the main body and in which current is induced by a magnetic field generated by the heating coil, and the main body. A knob switch including a metal member vibrating up and down with respect to the resonant coil according to vibrations generated on the upper surface of the knob switch and the heating coil to detect a resonant frequency between the heating coil and the knob switch, and the detected resonant frequency It characterized in that it comprises a vibration detection unit for determining the vibration amount of the vibration generated on the upper surface of the main body based on.

Description

Induction heating device capable of sensing vibration of an object to be heated {INDUCTION HEATING DEVICE CAPABLE OF SENSING VIBRATION OF THE HEATED BODY}

The present invention relates to an induction heating device capable of sensing vibration of a heating target by detecting a resonant frequency between a heating coil and a knob switch.

Recently, induction (induction heating device), which has been released one after another, is replacing gas stoves that have been popularly used in conventional homes and restaurants.

Unlike gas stoves, induction does not use flames generated by gas as a heat source, but uses induced current generated by a magnetic field as a heat source. The market size is growing exponentially.

However, users who are accustomed to using a conventional gas stove are not familiar with the heating performance of an induction stove, so they cannot accurately control the temperature of food, and thus, trial and error is occurring in which the food is heated until it is burned.

Overheating of such food basically not only spoils the food, but also causes the container containing the food to be destroyed, and in severe cases, it may cause a fire.

Accordingly, there is a demand for a method capable of automatically preventing overheating of food without a user's manual manipulation.

An object of the present invention is to provide an induction heating device capable of detecting vibration of an object to be heated by using resonance between a heating coil and a knob switch.

In addition, the present invention provides an induction heating device capable of adjusting the degree of electric heating of an object to be heated according to the degree of rotation of a knob switch.

In addition, the present invention is to provide an induction heating device capable of adjusting the degree of heat transfer to an object to be heated according to the amount of vibration of the main body.

In addition, the present invention provides an induction heating apparatus in which a knob switch receives power wirelessly from a heating coil and displays information about an amount of vibration.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

The present invention detects the resonance frequency between the heating coil and the knob switch, and determines the amount of vibration generated on the upper surface of the main body based on the change period of the resonance frequency, thereby using the resonance between the heating coil and the knob switch to heat the object. vibration can be detected.

In addition, the present invention detects a resonance frequency after selectively connecting a plurality of capacitors having different capacitances to a resonance coil according to the degree of rotation of the knob switch, and controls the amount of current flowing through the heating coil according to the detected resonance frequency. The degree of heat transfer to the object to be heated can be adjusted according to the degree of rotation of the knob switch.

In addition, the present invention can adjust the degree of heat transfer to the object to be heated by detecting the resonance frequency between the heating coil and the knob switch when the main body vibrates, and controlling the amount of current flowing through the heating coil according to the detected resonance frequency.

In addition, the present invention uses the induced current generated in the resonant coil as a power source, so that the knob switch receives power wirelessly from the heating coil and displays information about the amount of vibration.

The present invention has an effect of allowing the user to indirectly grasp the degree of heating of the object to be heated by detecting the vibration of the object to be heated using resonance between the heating coil and the knob switch and displaying the vibration to the user.

In addition, the present invention has an effect of improving user convenience by adjusting the degree of heat transfer to the object to be heated according to the degree of rotation of the knob switch.

In addition, the present invention has an effect of automatically preventing overheating of food without a user's manual operation by adjusting the degree of heat transfer to the object to be heated according to the amount of vibration of the main body.

In addition, the present invention has an effect of improving UX (User eXperience) for food cooking by allowing the knob switch to receive power wirelessly from the heating coil and display information about the amount of vibration.

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 is a block diagram of an induction heating apparatus according to an embodiment of the present invention.
2 is an internal configuration diagram of the knob switch shown in FIG. 1;
Figure 3 is an external perspective view of the induction heating device shown in Figure 1;
4 is a diagram for explaining resonance between a heating coil and a resonant coil;
5 is a graph showing how the combined impedance of a heating coil and a knob switch varies with frequency.
6 and 7 are structural diagrams according to each example of the knob switch shown in FIG. 3;
8 and 9 are diagrams illustrating detecting a resonance frequency between the knob switch and the heating coil according to FIGS. 6 and 7, respectively.
10 is a diagram showing an example of a resonance detection circuit constituting a vibration detection unit.
11 is a diagram showing how a resonant frequency changes according to a predetermined period;
12 is a diagram illustrating a state in which power is supplied to a communication unit and a sub-display unit included in a knob switch by a current induced in a resonant coil;

The above objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Hereinafter, the arrangement of an arbitrary element on the "upper (or lower)" or "upper (or lower)" of a component means that an arbitrary element is placed in contact with the upper (or lower) surface of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

In addition, when a component is described as "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components may be "interposed" between each component. ", or each component may be "connected", "coupled" or "connected" through other components.

The present invention relates to an induction heating device capable of sensing vibration of a heating target by detecting a resonant frequency between a heating coil and a knob switch.

Hereinafter, an induction heating apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 10 .

1 is a block diagram of an induction heating device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the internal configuration of a knob switch shown in FIG. 1 .

3 is an external perspective view of the induction heating device shown in FIG. 1;

4 is a diagram for explaining resonance between a heating coil and a resonant coil.

5 is a graph showing how the combined impedance of a heating coil and a knob switch varies with frequency.

6 and 7 are structural diagrams according to each example of the knob switch shown in FIG. 3, and FIGS. 8 and 9 show detecting a resonant frequency between the knob switch and the heating coil according to FIGS. 6 and 7, respectively. it is a drawing

10 is a diagram showing an example of a resonance detection circuit constituting a vibration detection unit, and FIG. 11 is a diagram showing how a resonance frequency changes according to a predetermined period.

12 is a diagram illustrating a state in which power is supplied to a communication unit and a sub-display unit included in a knob switch by a current induced in a resonant coil.

An induction heating device 1 according to an embodiment of the present invention may include a main body 10 and a knob switch 20 provided on the top of the main body 10 .

Referring to FIG. 1 , the main body 10 constituting the induction heating apparatus 1 may include a heating coil 11, a vibration detector 12, a heating control unit 13, and a display unit 14. In addition, referring to FIG. 2, the knob switch 20 constituting the induction heating apparatus 1 includes a resonant coil 21, a plurality of capacitors 22, a switch 23, a communication unit 24, and a sub display unit ( 25) may be included.

The main body 10 and the knob switch 20 shown in FIGS. 1 and 2 are according to one embodiment, and the components are not limited to the embodiment shown in FIGS. 1 and 2, and some of them as necessary. Elements may be added, changed or deleted.

Prior to a detailed description of each component shown in FIGS. 1 and 2 , the overall structure of the induction heating apparatus 1 of the present invention will be described with reference to FIG. 3 .

Referring to FIG. 3, the induction heating device 1 basically includes a body 10, a heating coil 11 provided on the upper portion of the body 10, a heating plate 10a provided on the heating coil 11, A display unit 14 and a knob switch 20 provided on the front of the main body 10 may be included.

The main body 10 is a case of the induction heating device 1, and may have various shapes and may have a rectangular parallelepiped shape as shown in FIG. 3.

Meanwhile, in FIG. 3, only one heating coil 11 and one knob switch 20 for controlling the heating coil 11 are shown in the induction heating device 1, but the induction heating device 1 includes a plurality of It may include a heating coil 11 and a plurality of knob switches (20).

The heating coil 11 may be provided on the upper part of the body 10 to perform an electric heating operation. More specifically, the heating coil 11 may generate a magnetic field by receiving current from a power supply source provided inside the main body 10, and the magnetic field vortexes in the object to be heated 2 located on the heating coil 11 It is possible to heat the object to be heated 2 by generating an electric current.

For efficient heat transfer operation by eddy current, it is preferable that the object to be heated 2 is made of a conductive material.

The heating plate 10a may be entirely provided on the upper surface of the main body 10 or selectively disposed on the heating coil 11 . The heating plate 10a may be made of a material having low thermal conductivity such as ceramic or tempered glass to selectively heat the object to be heated 2 .

The display unit 14 is provided in front of the main body 10 to display various information necessary for cooking to the user, and to display information about the temperature of the object to be heated 2, a warning display, etc. as will be described later. may be

The knob switch 20 is provided on the upper surface of the main body 10 and basically serves to control the degree of heating by the heating coil 11 according to the degree of rotation. In addition, the knob switch 20 serves as a medium to determine whether or not the contents of the object to be heated 2 are boiling.

First, a process of controlling the degree of heating by the heating coil 11 according to the rotation of the knob switch 20 will be described in detail.

Referring to FIG. 4, the knob switch 20 includes a resonance coil 21 magnetically coupled to the heating coil 11 of the main body 10, a plurality of capacitors 22 connected in parallel to the resonance coil 21, and A plurality of switching elements S1 and S2 selectively connecting the plurality of capacitors 22 and the resonant coil 21 in parallel may be included. Here, the plurality of capacitors 22 may have different capacitances.

The plurality of switching elements S1 and S2 may be included in the switch 23 such as an incremental type encoder or an absolute encoder, and when the knob switch 20 rotates, the above-described switching The elements S1 and S2 may be turned on/off according to the degree of rotation of the knob switch 20 .

4 , when the knob switch 20 is rotated by 60 ^° , the first switching element S1 is selectively turned on, so that the resonance coil 21 and the first capacitor ^C1 can be connected. When rotated, the second switching element S2 is selectively turned on so that the resonant coil 21 and the second capacitor C2 can be connected. When rotated 180 ^° , the first and second switching elements S1 and S2 ) are all turned on, so that the resonance coil 21 and the first and second capacitors C1 and C2 can be connected.

When the resonance coil 21 and at least one capacitor 22 are connected in parallel, the resonance coil 21 and the capacitor 22 constitute an LC parallel resonance circuit, and at this time, the heating coil of the main body 10 ( 11), the resonance coil 21 of the knob switch 20, and the capacitor 22 may resonate.

The vibration detector 12 provided in the main body 10 is connected to the heating coil 11 to detect a resonant frequency between the heating coil 11 and the knob switch 20 . Meanwhile, the heating control unit 13 may control the amount of current flowing through the heating coil 11 according to the resonance frequency detected by the vibration detection unit 12 .

Referring to FIG. 5, when the resonance coil 21 and at least one capacitor 22 are connected in parallel, the combined impedance of the heating coil 11 and the knob switch 20 viewed from the input terminal of the heating coil 11 ( |Z|) may vary with frequency. At this time, the graph of synthetic impedance against frequency may have an inflection point at the resonance frequency (f ₀ ), and the heating coil 11 and the knob switch 20 may operate at the resonance frequency (f ₀ ).

The vibration detector 12 detects a resonance frequency f ₀ between the heating coil 11 and the knob switch 20, and as described with reference to FIG. 4, each capacitor selectively connected to the resonance coil 21 ( Since the capacitances of 22) are different from each other, the resonance frequency f ₀ may be differently detected according to the on/off state of the switching element. Accordingly, the vibration detector 12 may detect a resonance frequency f ₀ between the heating coil 11 and the knob switch 20 differently according to the degree of rotation of the knob switch 20 .

A process of detecting the resonance frequency f ₀ by the vibration detector 12 will be described later with reference to FIGS. 8 to 11 .

The vibration detection unit 12 may provide information about the resonant frequency to the heating control unit 13, and the heating control unit 13 controls the amount of current flowing through the heating coil 11 according to the resonant frequency of the heating coil 11. You can adjust the degree of heat transfer.

For example, in FIG. 4 , when the knob switch 20 rotates 60 ^° , the amount of current flowing through the heating coil 11 can be controlled to a preset first amount of current, and when the knob switch 20 rotates 120 ^° , heating is performed. The amount of current flowing through the coil 11 can be controlled to a preset second amount of current, and when the knob switch 20 is rotated 180 ^° , the amount of current flowing through the heating coil 11 can be controlled to a preset third amount of current.

As described above, the present invention has an effect of improving user convenience by adjusting the degree of heat transfer to the object to be heated according to the degree of rotation of the knob switch.

Next, a process of determining whether the object to be heated 2 is overheated according to the resonance between the knob switch 20 and the heating coil 11 will be described in detail.

The knob switch 20 vibrates up and down with respect to the resonance coil 21, in which current is induced by the magnetic field generated from the heating coil 11, and the resonance coil 21 according to the vibration generated on the upper surface of the main body 10. It may include a metal member that does.

When the temperature of the contents of the object to be heated 2 increases, vibration may occur on the upper surface of the main body 10 in contact with the surface of the object to be heated 2 . At this time, the resonance coil 21 may move according to the same vibration width as the vibration occurring on the upper surface of the main body 10, and the metal member may vibrate up and down with respect to the vibrating resonance coil 21. Accordingly, the distance between the resonance coil 21 and the metal member may change according to the vibration period.

Meanwhile, when a current is induced in the resonance coil 21, an induced current due to a magnetic field generated in the resonance coil 21 may be generated in a metal member vibrating up and down with respect to the resonance coil 21. In addition, when a current is induced in the resonance coil 21 , capacitance may occur between the metal member that vibrates up and down with respect to the resonance coil 21 and the resonance coil 21 .

Accordingly, the equivalent impedance of the resonance coil 21 and the metal member may be changed according to the distance between the resonance coil 21 and the metal member.

In one example, referring to FIG. 6 , the knob switch 20 is in contact with the upper surface of the main body 10, the support case 26 in which the resonance coil 21 is supported, the resonance coil 21 and the plurality of capacitors described above. It may include a switch 23 selectively connecting the switch 22 and metal cases 27a and 27b connected to the first buffer member 28a provided above the switch 23 .

Here, the resonance coil 21 and the switch 23 may be provided on a printed circuit board (PCB) supported on the support case 26 .

The first buffer member 28a may be any member that buffers the physical connection between the support case 26 and the metal cases 27a and 27b. For example, the first buffering member 28a may be a button incorporating a spring.

At this time, the button may generate a specific input signal according to the pressure applied to the spring from the upper surface of the metal cases 27a and 27b. In addition, the button may rotate together with the rotation of the metal cases 27a and 27b, and as described with reference to FIG. 4, a specific input signal (eg, the switching elements S1 and S2 of FIG. 4) depends on the rotation angle. ) control signal).

The metal cases 27a and 27b may consist of an upper metal case 27a and a lower metal case 27b, and the upper metal case 27a and the lower metal case 27b may be coupled to each other through an arbitrary coupling member. can When the user rotates the knob switch 20, the metal cases 27a and 27b may rotate relative to the support case 26. In other words, the support case 26 is fixedly formed on the upper part of the main body 10, and the metal cases 27a and 27b can rotate with respect to the fixedly formed support case 26.

A sub display unit 25 capable of displaying text may be provided on the upper surfaces of the metal cases 27a and 27b, and a display operation of the sub display unit 25 will be described later.

Meanwhile, at least one magnetic material M may be further provided in the support case 26 . As shown in FIG. 6 , the magnetic material M is supported on the upper surface of the support case 26 and may protrude toward the upper metal case 27a through the hole formed in the PCB.

At least one magnetic material having a polarity opposite to that of the magnetic material M provided in the support case 26 may be provided on the lower surface of the upper metal case 27a. The magnetic materials provided in the upper metal case 27a and the support case 26 may form an attractive force with each other to form a constant fixing force at a specific position when the metal cases 27a and 27b rotate.

For example, as described above, when the degree of heat transfer of the heating coil 11 is controlled every time the knob switch 20 rotates by 60 ^° , three magnetic bodies are respectively 60 degrees on the lower surface of the upper metal case 27a It may be provided at intervals of ^o . At this time, the three magnetic materials may form a constant fixing force at each position when the metal cases 27a and 27b are rotated at 60 ^o , 120 ^o , and 180 ^o .

When vibration occurs in the main body 10 due to heating of the object to be heated 2, since the support case 26 is fixed to the main body 10, it can vibrate with the same vibration width as the main body 10. Accordingly, the resonance coil 21 provided in the support case 26 may also move according to the same vibration width as the vibration generated in the main body 10 .

At this time, since the metal cases 27a and 27b are connected to the PCB provided with the resonance coil 21 through the first buffer member 28a, the vibration time is different from the vibration generated in the main body 10 due to inertia. And it can move according to the vibration width. Accordingly, the distance between the metal cases 27a and 27b and the resonant coil 21 may change according to the vibration generated in the main body 10 .

When the distance between the resonant coil 21 and the metal cases 27a and 27b where the induced current is generated changes, as shown in FIG. 5, the combined impedance of the heating coil 11 and the knob switch 20 can increase or decrease, The resonant frequency (f ₀ ) between the heating coil 11 and the knob switch 20 may change according to the increase or decrease of the combined impedance.

At this time, the metal cases 27a and 27b may be equalized to the variable resistor Rc in the electrical circuit formed by the knob switch 20 .

Referring to FIG. 8, the metal cases 27a and 27b described above in the equivalent circuit of the heating coil 11 and the knob switch 20 have variable resistances Rc having different values depending on the distance between them and the resonant coil 21. ) can be equalized.

Accordingly, the combined impedance of the heating coil 11 and the knob switch 20 viewed from the input terminal of the heating coil 11 may change according to the size of the variable resistance Rc, and when the combined impedance changes, the combined impedance shown in FIG. As such, the resonance frequency f ₀ between the heating coil 11 and the knob switch 20 may change.

In another example, referring to FIG. 7 , the knob switch 20 is in contact with the upper surface of the main body 10 and includes a support case 26 in which the resonance coil 21 is supported, and a second shock absorber provided on the resonance coil 21 . It may include a member 28b and a metal thin film 29 provided on the second buffer member 28b.

Since the support case 26, the switch 23, the first buffer member 28a, the PCB, and the magnetic material M shown in FIG. 7 are the same as those described with reference to FIG. 6, a detailed description thereof will be omitted.

In FIG. 7 , the cases 27a' and 27b' may be composed of an upper case 27a' and a lower case 27b', and each case 27a and 27b is a metal case 27a, which has been described with reference to FIG. 6 . 27b) may have the same structure. However, while the metal cases 27a and 27b described with reference to FIG. 6 are made of metal to generate an induced current, the cases 27a' and 27b' of FIG. 7 may be made of any material other than metal. there is.

A sub display unit 25 capable of displaying brightness and color may be provided on the upper surface of the upper case 27a', and a display operation of the sub display will be described later.

When vibration occurs in the main body 10 due to heating of the object to be heated 2, since the support case 26 is fixed to the main body 10, it can vibrate with the same vibration width as the main body 10. Accordingly, the resonance coil 21 provided in the support case 26 may also move according to the same vibration width as the vibration generated in the main body 10 .

At this time, since the resonant coil 21 and the metal thin film 29 are disposed with the second buffer member 28b interposed therebetween, the metal thin film 29 vibrates differently from the vibration generated in the main body 10 due to inertia. It can move according to time and amplitude of oscillation. Accordingly, the distance between the metal thin film 29 and the resonant coil 21 may change according to the vibration generated in the main body 10 .

Here, the second buffer member 28b may be made of any non-conductive material capable of buffering an external force applied to the resonance coil 21 or the metal thin film 29, and, for example, the second buffer member 28b ) may be a sponge.

A capacitance may be formed between the resonance coil 21 and the metal thin film 29 , and the capacitance may vary according to an interval between the resonance coil 21 and the metal thin film 29 . When the capacitance between the resonance coil 21 and the metal thin film 29 changes, as shown in FIG. 5, the combined impedance of the heating coil 11 and the knob switch 20 can increase or decrease, and accordingly the heating coil ( 11) and the resonant frequency f ₀ between the knob switch 20 may change.

Meanwhile, the metal thin film 29 is composed of a plurality of sub-metal thin films, and slits may be formed between adjacent sub-metal thin films.

As shown in FIG. 7 , the metal thin film 29 may have a ring shape corresponding to the resonant coil 21 . When the metal thin film 29 vibrates up and down with respect to the resonance coil 21, an induced current in a circumferential direction may be generated in the metal thin film 29.

When the distance between the resonant coil 21 and the metal thin film 29 is very short, the size of the induced current generated in the metal thin film 29 may increase, and accordingly, an inflection point does not occur in the graph of the combined impedance shown in FIG. 5. may not be In other words, the heating coil 11 and the knob switch 20 may not resonate.

Accordingly, in order to prevent generation of induced current in the circumferential direction in the metal thin film 29, the metal thin film 29 is divided into a plurality of sub-metal thin films, and slits having a predetermined width may be formed between the sub-metal thin films. .

The metal thin film 29 may be equivalent to a variable capacitance Cm in an electrical circuit formed by the knob switch 20 .

Referring to FIG. 9, in the equivalent circuit of the heating coil 11 and the knob switch 20, the metal thin film 29 described above has a variable capacitance (Cm) having a different value depending on the distance from the resonant coil 21. can be equalized.

Accordingly, the combined impedance of the heating coil 11 and the knob switch 20 viewed from the input end of the heating coil 11 may vary according to the size of the variable capacitance Cm, and when the combined impedance changes, as shown in FIG. As such, the resonance frequency f ₀ between the heating coil 11 and the knob switch 20 may change.

As described above, the vibration detector 12 detects the changing resonance frequency f ₀ , and determines the amount of vibration generated on the upper surface of the main body 10 based on the detected resonance frequency f ₀ . .

More specifically, the vibration detector 12 is connected to the input terminal of the heating coil 11 and detects a frequency selective characteristic between the heating coil 11 and the knob switch 20 to detect the resonance frequency f ₀ . .

More specifically, the vibration detection unit 12 includes a resonance detection circuit 12a outputting a pulse having a resonance frequency f ₀ between the heating coil 11 and the knob switch 20, and a change in the resonance frequency f ₀ It may include a processor (12b) for determining the vibration amount of the vibration generated on the upper surface of the main body 10 based on the period.

The resonance detection circuit 12a is a circuit that outputs a pulse having an arbitrary size, and may include an arbitrary circuit that outputs a pulse having a resonance frequency f ₀ of the heating coil 11 and the knob switch 20. there is.

For example, referring to FIG. 10 , the resonance detection circuit 12a has a heating coil 11 connected to two input terminals in parallel and outputs a pulse having a resonance frequency f ₀ through an output terminal. Op-Amp) may be included.

More specifically, the heating coil 11 may be connected in parallel between the (+) input terminal and the (-) input terminal of the op-amp, and the output terminal of the op-amp may be connected to the (+) input terminal.

In addition, a reference voltage (V _ref ) determined by the power supply voltage (V _s ) and the voltage distribution resistors (R ₁ and R ₂ ) may be applied to the (-) input terminal of the opamp. Accordingly, a voltage increased or decreased by the voltage applied to both ends of the heating coil 11 from the reference voltage V _ref may be applied to the (+) input terminal of the opamp.

By having the above configuration, the resonance detection circuit 12a may function as an LC oscillator and output a pulse having a resonance frequency f ₀ through an output terminal.

The processor 12b may receive a pulse from the resonance detection circuit 12a and detect the resonance frequency f ₀ by identifying the frequency of the pulse. Subsequently, the processor 12b may identify a period in which the resonant frequency f ₀ is changed, and determine the period as an amount of vibration.

Referring to FIG. 11 , in one example, the resonance detection circuit 12a may output a sinusoidal pulse that vibrates according to a resonance frequency f ₀ . The processor 12b may detect the resonance frequency f ₀ by identifying the frequency of the sine wave pulse, identify a period in which the resonance frequency f ₀ changes, and determine the amount of vibration based on the period.

More specifically, the resonance frequency (f ₀ ) may change (f ₀ -> f ₀ ′) according to the vibration period occurring in the main body. When the change period of the resonant frequency is T ₀ , the processor 12b may determine 1/T ₀ as the amount of vibration [Hz]. For example, when T ₀ is 20 [ms], the processor 12b may determine the amount of vibration generated on the upper surface of the main body 10 as 50 [Hz].

The heating control unit 13 may control the amount of current flowing through the heating coil 11 according to the amount of vibration detected by the above method.

More specifically, the heating controller 13 may control the amount of current flowing through the heating coil 11 in inverse proportion to the detected amount of vibration. For example, the heating controller 13 may control the amount of current flowing through the heating coil 11 to be low as the amount of vibration increases, and may control the amount of current flowing through the heating coil 11 to increase as the amount of vibration decreases.

Accordingly, the degree of heat transfer of the heating coil 11 may decrease as the amount of vibration increases, and may increase as the amount of vibration decreases.

In addition, the heating controller 13 may control the amount of current flowing through the heating coil 11 as a reference value when the amount of vibration exceeds the reference amount for a predetermined time or more.

More specifically, the heating control unit 13 counts the time from when the vibration amount exceeds the reference vibration amount, and if the counted cumulative time is greater than or equal to a preset time, the amount of current flowing through the heating coil 11 can be controlled as a reference value. there is. Here, the reference value may be set lower than the current amount flowing through the heating coil 11 .

As described above, the present invention has an effect of automatically preventing overheating of food without a user's manual operation by adjusting the degree of heat transfer to the object to be heated according to the amount of vibration of the main body.

Meanwhile, referring to FIG. 3 again, the display unit 14 provided in the main body 10 may receive vibration amount information from the vibration detection unit 12 and display temperature information corresponding to the vibration amount information.

The vibration detection unit 12 may convert information about the detected amount of vibration into a digital signal and provide the information to the display unit 14 . The display unit 14 may display information about the amount of vibration by converting the provided digital signal into an output signal.

For example, the display unit 14 may display the amount of vibration as a number in [Hz] or display a warning light outputting different colors according to the amount of vibration. More specifically, a green warning light may be displayed when the vibration amount is within a certain range, a yellow warning light may be displayed when the vibration amount is within a certain range, and a red warning light may be displayed when the vibration amount exceeds a certain range. .

Meanwhile, the communication unit 24 of the knob switch 20 may receive vibration amount information from the vibration detection unit 12, and the sub display unit 25 may display temperature information corresponding to the received vibration amount information.

The communication unit 24 may perform wireless communication with the vibration detection unit 12 to receive information on the amount of vibration and provide the information to the sub display unit 25 . The sub display unit 25 may convert information about the amount of vibration into an output signal and output the converted signal.

More specifically, referring to FIG. 6 , the sub display unit 25 is provided on the upper surface of the metal cases 27a and 27b of the knob switch 20 to display the amount of vibration as a number in [Hz].

Also, referring to FIG. 7 , the sub display unit 25 is provided on the upper surface of the case 27a' of the knob switch 20 to display a color corresponding to the amount of vibration. For example, the sub display unit 25 may display a visible color having a wavelength proportional to the amount of vibration. More specifically, the sub display unit 25 may display a color having a shorter wavelength (eg, purple) as the amount of vibration decreases, and display a color having a longer wavelength (eg, red) as the amount of vibration increases. can do.

As described above, the present invention detects the vibration of the object to be heated using the resonance between the heating coil and the knob switch and displays it to the user, so that the user can indirectly grasp the degree of heating of the object to be heated. .

Meanwhile, at least one of the communication unit 24 and the sub display unit 25 may be supplied with power by a current induced in the resonant coil 21 .

Referring to FIG. 12, the knob switch 20 includes a DC link capacitor (C _DC ) and a DC link capacitor (C _DC ) connected in parallel with the capacitor 22 in addition to the resonant coil 21 and the capacitor 22 in the switch. And a diode (D) for limiting the direction of the current flowing between the capacitor 22 may be further included. Accordingly, the DC link capacitor (C _DC ) may be charged by the current induced in the resonance coil 21 .

At this time, at least one of the communication unit 24 and the sub-display unit 25 may be connected in parallel to the DC link capacitor (C _DC ) to receive power from the DC link capacitor (C _DC ).

In other words, the above-described wireless communication operation of the communication unit 24 and display operation of the sub display unit 25 may be performed using the voltage stored in the DC link capacitor C _DC .

As described above, the present invention has an effect of improving UX (User eXperience) for food cooking by allowing the knob switch to receive power wirelessly from the heating coil and display information about the amount of vibration.

As described above, the present invention has been described with reference to the drawings illustrated, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and various modifications are made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that variations can be made. In addition, although the operational effects according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be recognized.

Claims (13)

A heating coil provided in the main body to generate a magnetic field;
A knob including a resonance coil provided on an upper surface of the main body and in which current is induced by a magnetic field generated by the heating coil, and a metal member that vibrates up and down with respect to the resonance coil according to vibrations generated on the upper surface of the main body. switch; and
And a vibration detection unit connected to the heating coil to detect a resonance frequency between the heating coil and the knob switch, and determining a vibration amount of vibration generated on an upper surface of the main body based on the detected resonance frequency.
induction heating device.
According to claim 1,
The knob switch
a support case in contact with an upper surface of the main body and supporting the resonant coil;
a switch selectively connecting the resonant coil and a plurality of capacitors;
A metal case connected to a first buffer member provided above the switch
induction heating device.
According to claim 1,
The knob switch
a support case in contact with an upper surface of the main body and supporting the resonant coil;
a second buffer member provided on the resonant coil;
Including a metal thin film provided on the second buffer member
induction heating device.
According to claim 3,
The metal thin film is composed of a plurality of sub-metal thin films,
An induction heating device in which a slit is formed between adjacent sub-metal thin films.
According to claim 1,
The vibration detector
a resonance detection circuit outputting a pulse having a resonance frequency between the heating coil and the knob switch;
And a processor for determining the vibration amount based on a change period of the resonance frequency.
induction heating device.
According to claim 5,
The resonance detection circuit
An induction heating apparatus including an op-amp to which the heating coil is connected in parallel to two input terminals and to output a pulse having the resonant frequency through an output terminal.
According to claim 1,
The induction heating apparatus further includes a display unit provided in the main body, receiving vibration amount information from the vibration detection unit and displaying temperature information corresponding to the vibration amount information.
According to claim 1,
The knob switch further includes a communication unit and a sub display unit,
The communication unit receives vibration amount information from the vibration detection unit,
The sub-display unit displays temperature information corresponding to the received vibration amount information.
According to claim 8,
At least one of the communication unit and the sub-display unit is supplied with power by a current induced in the resonant coil.
According to claim 1,
The knob switch
An induction heating device comprising a plurality of switching elements selectively connecting the resonance coil and a plurality of capacitors having different capacitances in parallel.
According to claim 1,
The induction heating apparatus further comprises a heating control unit for controlling the amount of current flowing through the heating coil according to the detected resonant frequency.
According to claim 1,
The induction heating apparatus further comprises a heating control unit for controlling the amount of current flowing through the heating coil according to the detected amount of vibration.
According to claim 12,
The heating control unit
An induction heating device that controls the amount of current flowing through the heating coil as a reference value when the amount of vibration exceeds a reference amount of vibration for a predetermined time or more.

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