KR101634526B1 - A cooking apparatus using microwave - Google Patents

Abstract

The present invention relates to a microwave-assisted cooking appliance. The microwave cooker according to the present invention includes a frequency oscillator for oscillating a frequency corresponding to an input frequency control signal, an amplifier for amplifying the oscillated frequency signal and outputting a microwave for heating an object inside the cavity, And a frequency control signal generator for generating a frequency control signal for varying the output period of the microwave according to the calculated heating efficiency. Thus, the output period of the microwave can be varied.

Cooking equipment, microwave, efficiency, frequency, control

Description

[0001] The present invention relates to a cooking apparatus using microwave,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a microwave-assisted cooking apparatus, and more particularly, to a microwave-assisted cooking apparatus capable of varying an output period of a microwave.

Generally, a microwave cooker receives food and closes it. When the operation button is pressed, a voltage is applied to the high-voltage generator, and a commercial voltage applied to the high-voltage generator is boosted to supply power to the magnetron generating microwaves And the microwave generated by the magnetron is transmitted to the cavity through a waveguide or the like.

In this case, the microwave cooker is used to heat the food by frictional heat generated by vibrating the molecules constituting the food by 2.45 billion times per second by irradiating the microwave generated from the magnetron to the food.

Such microwave-assisted cooking devices are widely used in general households due to various advantages such as easy temperature control, saving cooking time, and convenience of operation.

However, when the food is cooked using the microwave, there is a problem that the temperature is not uniformly heated due to the surface deviation of the food or the like, and a temperature difference is partially generated in the food. In addition, there is a problem that the temperature deviation during cooking varies depending on the type of food stored in the cooking appliance.

An object of the present invention is to provide a microwave cooking device capable of varying the output period of a microwave.

According to an aspect of the present invention, there is provided a microwave cooking device comprising: a frequency oscillator for oscillating a frequency corresponding to an input frequency control signal; An amplifying unit for outputting a microwave for heating the microwave, an efficiency calculating unit for calculating the heating efficiency based on the reflected microwave, and a frequency control signal generating unit for varying the output period of the microwave according to the calculated heating efficiency And a frequency control signal generator.

According to the embodiment of the present invention, the heating efficiency can be calculated based on the reflected microwave, and the output period of the microwave can be varied according to the calculated heating efficiency. Further, the heating efficiency can be calculated in real time without a separate microprocessor, and the output period of the microwave can be varied accordingly.

In addition, during the heating operation in the heating period without any additional scan period, the output period of the microwave can be varied according to the calculated heating efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a partial perspective view of a microwave oven according to an embodiment of the present invention, and FIG. 2 is a sectional view of the cooking apparatus of FIG. 1.

The microwave cooker 100 according to the embodiment of the present invention includes a door 106 having a cooking window 104 attached to a front portion of a main body 102, And an operation panel 108 is coupled to one side of the front surface of the main body 102. [

The door 106 opens and closes the cavity 134. Although not shown in the drawing, a filter unit (not shown) for shielding microwaves may be provided inside the door 106. [

The operation panel 108 includes an operation portion 107 for operating the operation of the cooking appliance and a display portion 105 for displaying the operation of the cooking appliance and the like.

The interior of the body 102 is provided with a cavity 134 having a receiving space of a predetermined size so that the object to be heated 140, for example, food is received and cooked by microwaves.

A microwave generator 110 for generating a microwave is installed on the outer surface of the cavity 134. A microwave generated by the microwave generator 110 is supplied to the output side of the microwave generator 110, And a microwave transfer unit 112 for guiding the microwaves to the inside of the cavity 134 are disposed.

The microwave generator 110 may include a magnetron or a solid state power amplifier (SSPA) using a semiconductor. The solid state power amplifier (SSPA) has the advantage of occupying less space than the magnetron.

On the other hand, the solid state power amplifier (SSPA) includes a hybrid microwave integrated circuit (HMIC) having separate passive elements (capacitors and inductors) and active elements (transistors, etc.) The active devices can be implemented as monolithic microwave integrated circuits (MMICs) implemented as a single substrate.

Meanwhile, according to the embodiment of the present invention, the microwave generating unit 110 can generate and output a plurality of microwaves. The frequency range of such microwaves may be in the vicinity of approximately 900 MHz to 2500 Hz. In particular, it may be within a predetermined range around 915 MHz or within a predetermined range around 2450 MHz. The microwave generator 110 will be described in detail below with reference to FIG.

The microwave transmitter 112 transmits the microwave generated by the microwave generator 110 to the cavity 134. The microwave transmitting unit 112 may include a waveguide or a coaxial line. In order to transmit the generated microwave to the microwave transmitting unit 112, a feeder 142 may be connected as shown in the figure.

The microwave transmitting unit 112 may be formed as an opening having an opening 145 in the cavity 134 as shown in the drawing. However, the present invention is not limited thereto, and an antenna may be coupled to the end It is possible. The opening 145 may be formed in various shapes such as a slot shape. Through the opening 145 or the antenna, the microwave is emitted into the cavity 134.

Although the opening 145 is shown as being disposed on the upper side of the cavity 134, the opening 145 may be disposed on the lower side or the side of the cavity 134, and a plurality of openings may be disposed It is also possible. The same applies to the case where they are coupled through the antenna instead of the opening 145.

A power supply 114 is provided below the microwave generator 110 to supply power to the microwave generator 110.

The power supply 114 may include a high voltage transformer that boosts the power supplied to the cooking appliance 100 to a high voltage and supplies the power to the microwave generator 110, And an inverter for supplying a high output voltage of about 3500 V or more to the microwave generator 110.

A cooling fan (not shown) for cooling the microwave generator 110 may be installed around the microwave generator 110.

Although not shown in the drawing, a turntable (not shown) for rotating the heating object 140 may be installed inside the cavity 134. Inside the cavity 134, A stirrer fan (not shown) may be created, and a cover (not shown) may be provided to prevent damage to the stirrer fan (not shown). The stuttering fan (not shown) can be regarded as a kind of the above-mentioned antenna.

The above microwave cooking apparatus 100 is configured such that the user opens the door 106 and puts the heating object 140 in the cavity 134 and then moves the operation panel 108 ), Particularly, by operating the operation unit 107 and pressing the cooking selection button (not shown) and the start button (not shown).

That is, the power supply unit 114 in the cooking apparatus 100 boosts the input AC power to a high-voltage DC power and supplies the boosted power to the microwave generation unit 110. The microwave generation unit 110 generates the corresponding microwave And the microwave transmitting unit 112 transmits the generated microwave to the cavity 134 to emit the generated microwave. As a result, the heating object 140, for example, the food inside the cavity 134 is heated.

FIG. 3 is a block diagram schematically showing the inside of the cooking apparatus of FIG. 1;

Referring to the drawings, a cooking apparatus 100 according to an embodiment of the present invention includes a microwave generating unit 110. Further, the cooking apparatus 100 may further include a microwave transmitting unit 112.

The microwave generating unit 110 includes a frequency oscillating unit 332, an amplifying unit 336, an efficiency detecting unit 305, and a frequency control signal generating unit 310. The microwave generating unit 110 may further include a directional coupler 338.

The frequency oscillating unit 332 oscillates in accordance with the frequency control signal from the frequency control signal generating unit 310 to output a microwave of the corresponding frequency. The frequency oscillator 322 may include a voltage controlled oscillator (VCO). The voltage control oscillator (VCO) oscillates at a frequency corresponding to the voltage level of the frequency control signal. For example, the greater the voltage level of the frequency control signal, the greater the frequency generated by the oscillation in the voltage controlled oscillator VCO.

The amplifying unit 336 amplifies the frequency signal oscillated by the frequency oscillating unit 332 and outputs a microwave. As described above, the amplifying unit 336 may include a solid state power amplifier (SSPA) using semiconductor devices, and may include monolithic microwave integrated circuits (MMICs) using a single substrate . As a result, the size can be reduced and the devices can be integrated.

Although not shown in the drawing, a level adjusting unit (not shown) may further be provided between the frequency oscillating unit 332 and the amplifying unit 336. That is, the frequency oscillator 332 can oscillate the frequency signal to output a microwave at a power corresponding to the power control signal. The level regulator (not shown) may include a voltage controlled attenuator (VCA). According to the voltage level of the power control signal, the voltage control attenuator VCA performs the correction operation so that the microwave is output at the corresponding power. For example, the greater the voltage level of the power control signal, the greater the power level of the signal output from the voltage control attenuator VCA.

The directional coupler (DC) 338 transfers the microwave amplified by the amplifying unit 336 to the microwave transmitting unit 112. The microwave outputted from the microwave transmitting unit 112 heats the object in the cavity 134. On the other hand, the microwave reflected without being absorbed by the object in the cavity 134 can be input to the directional coupler 338 through the microwave transfer unit 112 again. The directional coupler 338 transmits the reflected microwave to the efficiency calculator 305.

The microwave generator 110 is disposed between the directional coupler 338 and the frequency control signal generator 310 and includes a DC converter (not shown) for converting the reflected microwave into a control signal . Here, the DC conversion unit (not shown) can be implemented as a diode device.

The microwave generating unit 110 is disposed between the amplifying unit 336 and the directional coupler 338. When the microwave amplified by the amplifying unit 336 is transmitted to the cavity 134, (Not shown) for passing microwaves reflected by the cavity 134 and blocking microwaves reflected from the cavity 134. Here, the isolation unit (not shown) may be implemented as an isolator.

The efficiency calculation unit 305 calculates the heating efficiency based on the microwave reflected into the cavity 134 without being absorbed by the object in the microwave.

Here, Pt represents the power of the microwave emitted into the cavity 134, Pt represents the power of the microwave reflected from the cavity 134, and he represents the heating efficiency of the microwave.

According to the above-described expression (1), the heating efficiency he becomes smaller as the power of the reflected microwave becomes larger.

On the other hand, when a plurality of microwaves are emitted into the cavity 134, the efficiency calculation unit 305 calculates the heating efficiency he for each frequency of a plurality of microwaves. Such heating efficiency calculation can be performed during the whole cooking section, according to the embodiment of the present invention. In the embodiment of the present invention, the heating efficiency (he) is directly calculated while heating the object, and the heating period (he) of the microwave is determined according to the heating efficiency (he) Can be changed in real time.

The frequency control signal generation unit 310 generates and outputs a frequency control signal so as to vary the output period of the microwave in accordance with the calculated heating efficiency. The frequency oscillator 332 oscillates at a frequency corresponding to the input frequency control signal.

The frequency control signal generating unit 310 generates the frequency control signal so that the output period of the microwave is shortened when the calculated heating efficiency he is high. That is, while sweeping the plurality of microwaves sequentially, the output period of each microwave can be varied according to the calculated heating efficiency. That is, the higher the heating efficiency (he), the smaller the corresponding output period is. Thus, microwaves can be uniformly absorbed by the heating object 140 in the cavity 134 for each frequency, so that the heating object 140 can be uniformly heated. Detailed operation of the frequency control signal generator 310 will be described later with reference to FIG.

On the other hand, the frequency control signal generator 310 may control to output a microwave of the corresponding frequency only when the heating efficiency he calculated for each frequency is equal to or greater than the set value. That is, by excluding the microwave having a frequency with a significantly lower heating efficiency (he) from the actual heating section, the heating object 140 can be uniformly heated efficiently.

Meanwhile, the above-described cooking apparatus 100 can vary the output period of the microwave in real time according to heating efficiency, so that a separate storage unit or the like is not required, and a separate microprocessor can be omitted.

The directional coupler 338 and the like in the microwave generating unit 110 as well as the efficiency calculating unit 305, the frequency control signal generating unit 310, the frequency oscillating unit 332, the amplifying unit 336, It is also possible to implement it as one module. That is, they are all arranged on one substrate, and can be implemented as one module.

The power supply unit 114 boosts the power supplied to the cooking apparatus 100 to a high pressure and outputs the power to the microwave generation unit 110. The power supply 114 may be implemented as a high-voltage transformer or an inverter.

4 is a view showing the inside of the frequency control signal generating unit of FIG.

The frequency control signal generation unit 310 includes a comparison unit 410, a weight determination unit 420, and a summation unit 430.

The comparing unit 410 compares the heating efficiency he calculated by the efficiency calculating unit 305 with the reference efficiency href. For example, the comparator 410 may output a difference signal Sd between the heating efficiency he and the reference efficiency href. If the heating efficiency he value is greater than the reference efficiency href value then a positive difference signal may be output and if the heating efficiency he value is less than the reference efficiency href value, A signal can be output.

The weight determination unit 420 sets the weight Sw based on the difference signal Sd from the comparison unit 410. [ For example, the weight Sw can be set in proportion to the difference signal Sd. That is, the weight Sw can be set to be smaller as the calculated heating efficiency he is larger than the reference efficiency href.

Meanwhile, the weight determining unit 420 may include an integrator (not shown) for integrating the difference signal Sd to shorten the entire sweep period of the microwave. On the other hand, it may further include a limiter (not shown) for limiting the level of the difference signal Sd integrated in the amplifier (not shown).

The summing unit 430 sums the weight signal Sw determined by the weight determining unit 420 and the reference frequency control signal Sf1 and outputs the finally determined frequency control signal Sfc. Here, the reference frequency control signal Sf1 refers to a frequency control signal generated so that the frequency of the microwave is sequentially increased in accordance with time.

5 is a view showing a reference frequency control signal and a corresponding frequency signal.

Referring to the drawings, it is shown that the level of the reference frequency control signal Sf1 sequentially increases with time (FIG. 5 (a)). According to this, the frequency oscillated by the frequency oscillating unit 332 gradually increases with time (FIG. 5 (a)). Therefore, the output period of the microwave emitted into the cavity is constantly allocated to each microwave.

In the embodiment of the present invention, the output period of each constantly allocated microwave is varied according to the heating efficiency (he), so that the object in the cavity is uniformly heated.

FIG. 6 is a view showing a frequency control signal varying according to heating efficiency, and FIG. 7 is a view showing that a microwave output period varies with time.

6 (a) shows an example of the heating efficiency he calculated by the efficiency calculating unit 305. As shown in FIG. Referring to the drawing, microwaves having frequencies f2 and f6 have heating efficiencies higher than the reference efficiency href, microwaves having a frequency f4 have heating efficiencies lower than the reference efficiency href, and f1, f3, it can be seen that the microwave having the frequencies f5 and f7 has the same heating efficiency as the reference efficiency href.

As described above, the comparator 410 compares the calculated heating efficiency he and the reference efficiency href and outputs the difference signal Sd. The weight determining unit 420 determines the difference signal Sd, And assigns a weight value Sw based on the weight value Sw.

In FIG. 6 (b), the higher the heating efficiency (he), the lower the weighting value. It is also possible to set the heating efficiency he to have a lower weight as the heating efficiency he is higher than the reference efficiency href.

7 shows the output period of the microwave in relation to the frequency according to the final frequency control signal Sfc obtained by adding the weight Sw from the weight determining unit 420 and the reference frequency control signal Sf1.

The case of generating the frequency control signal without taking the weight according to the heating efficiency into consideration is sequentially increased in the same manner as the dotted line (corresponding to Fig. 5 (a)). However, according to the embodiment of the present invention, , The output period of each microwave is varied as shown by the solid line.

That is, the output periods of the respective microwaves corresponding to f2 and f6 are set to be smaller, respectively, because the corresponding heating efficiency is large. Since the corresponding heating efficiency is small in the output period of the microwave corresponding to f4, . The output periods of the respective microwaves corresponding to the other f1, f3, f5, and f7 can be set to be constant without any change.

Accordingly, the output period can be varied, and the object in the cavity 134 can be irradiated with a plurality of microwaves and uniformly heated.

 While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

1 is a partial perspective view of a microwave oven according to an embodiment of the present invention.

Fig. 2 is a sectional view of the cooking apparatus of Fig. 1;

FIG. 3 is a block diagram schematically showing the inside of the cooking apparatus of FIG. 1;

4 is a view showing the inside of the frequency control signal generating unit of FIG.

5 is a view showing a reference frequency control signal and a corresponding frequency signal.

6 is a view showing a frequency control signal varying according to heating efficiency.

FIG. 7 is a view showing that the output period of the microwave varies with time. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

110: microwave generating unit 112: microwave transmitting unit

114: power supply unit 134: cavity

305: efficiency detecting unit 310: frequency control signal generating unit

332: frequency oscillation unit 336:

Claims (8)

A frequency oscillator for oscillating a corresponding frequency according to an input frequency control signal; An amplifier for amplifying the oscillated frequency signal and outputting a microwave for heating an object inside the cavity; An efficiency calculation unit for calculating a heating efficiency based on the reflected microwave; And A frequency control signal generator for generating the frequency control signal to vary the output period of the microwave according to the calculated heating efficiency; Lt; / RTI > Wherein the frequency control signal generator comprises: The frequency of the microwave is sequentially changed within a predetermined range of the frequency of the microwave outputted for heating the object inside the cavity, and the microwave is output, and as the calculated heating efficiency is higher, And the frequency control signal is generated so that the microwave is uniformly absorbed by the frequency. delete The method of claim 1, wherein Wherein the frequency control signal generator comprises: A comparison unit comparing the calculated heating efficiency with a reference efficiency; A weight determining unit for determining a weight based on a difference signal from the comparing unit; And And a summation unit for summing the determined weight and a reference frequency control signal that sequentially rises in level. The method of claim 3, Wherein the weight determining unit includes: And the weight is set to be smaller as the calculated heating efficiency is larger than the reference efficiency. The method of claim 3, wherein Wherein the weight determining unit includes: An integrator for integrating the difference signal; And And a limiter for limiting the level of the integrated difference signal. The method according to claim 1, And a microwave transmitting unit for transmitting the microwave outputted from the amplifying unit to the inside of the cavity. The method according to claim 1, Further comprising a directional coupler that transmits the microwave into the cavity and transmits microwaves reflected from the cavity to the efficiency calculator. The method according to claim 1, Wherein the frequency control signal generator comprises: Wherein the frequency control signal is generated so as to vary the output period of the microwave during the cooking interval.

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