KR101625873B1 - A cooking apparatus using microwave - Google Patents

Abstract

The present invention relates to a microwave-assisted cooking appliance. A microwave-assisted cooking device includes a microwave generating unit for generating and outputting a plurality of microwaves to heat an object inside a cavity, and a microwave generating unit for generating and outputting a single microwave to heat an object inside the cavity Magnetron. As a result, the operation efficiency can be improved.

Cookware, Microwave, Magnetron

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave-assisted cooking apparatus, and more particularly, to a microwave-assisted cooking apparatus capable of improving operation efficiency.

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-assisted cooking apparatus capable of improving operation efficiency.

According to an aspect of the present invention, there is provided a microwave cooking device including a microwave generating unit for generating and outputting a plurality of microwaves for heating an object inside a cavity, And a magnetron for generating and outputting a single microwave.

According to the embodiment of the present invention, a microwave generating unit for generating and outputting a plurality of microwaves to heat an object in a cavity, and a magnetron for generating and outputting a single microwave to heat the object in the cavity By using this, the operation efficiency can be improved.

Particularly, in the defrosting process during the cooking process, it is possible to enhance the operation of the microwave generating unit and defrost the object uniformly.

Further, during the heating process during the cooking process, the operation of the magnetron can be enhanced, and the heating efficiency can be increased.

On the other hand, the heating efficiency is calculated on the basis of the output microwave output from the microwave generating unit, and the output period of the microwave can be varied according to the calculated heating efficiency. This makes uniform heating possible.

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 first microwave transfer unit 112 for guiding the microwave to the inside of the cavity 134 is disposed.

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

The first microwave transmitting unit 112 may be formed as an opening having an opening 145 into the cavity 134 as shown in the drawing, but the present invention is not limited thereto, and an antenna may be coupled to the end It is also 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 magnetron (115) generates and outputs a single microwave to heat the object inside the cavity. The microwave at this time may be approximately 915 MHz or 2450 MHz. Hereinafter, it is described that the magnetron 115 outputs a microwave of 2450 MHz, which has a better heating efficiency.

The second microwave transmitting unit 113 transmits the microwave generated and output from the magnetron 115 to the cavity 134. The second microwave transmitting unit 113 may include a waveguide or a coaxial line. A feeder (not shown) may be connected to transmit the generated microwave to the second microwave transmitting unit 113.

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 the magnetron 115, And an inverter for supplying a high output voltage of about 3500 V or more generated by performing the operation to the microwave generating unit 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).

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 generator 110 and the magnetron 115. The microwave generator 110, The first microwave transmitting unit 112 and the second microwave transmitting unit 1130 are generated by the microwave generating unit 110 and the magnetron 115, respectively, And then discharges the microwave to the cavity 134. [ Thus, the heating object 140 in the cavity 134, for example, the cooking material is cooked.

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 generator 110 and a magnetron 115. The cooking apparatus 100 may further include a control unit 310, a first microwave transmitting unit 112, and a second microwave transmitting unit 113.

The microwave generating unit 110 includes a frequency oscillating unit 332, a level adjusting unit 334, and an amplifying unit 336. 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 control 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 level adjuster 334 oscillates in accordance with the power control signal from the control unit 310 to output the microwave at the corresponding power. The level adjuster 334 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 amplifying unit 336 performs an amplifying operation so as to output through the frequency oscillating unit 332 and the level adjusting unit 334 at the set frequency and power. 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 . Thus, the amplification unit 336 can be easily controlled by the control unit 310, and its size can be reduced, so that the devices can be integrated.

The directional coupler (DC) 338 transfers the microwave amplified and amplified by the amplifying unit 336 to the first microwave transmitting unit 112. The microwave outputted from the first microwave transmitting unit 112 heats the object in the cavity 134. On the other hand, the microwave that is not absorbed by the object but is reflected can be input to the directional coupler 338 through the first microwave transmitter 112 again. The directional coupler 338 transmits the reflected microwave to the controller 310.

The microwave generating unit 110 may further include a DC converting unit (not shown) disposed between the directional coupler 338 and the control unit 310 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 directional coupler 338 and the like including the frequency oscillator 332, the level controller 334 and the amplifier 336 in the microwave generator 110 may be implemented as a module . That is, they are all arranged on one substrate, and can be implemented as one module. With the integration of such elements, the microwave generator 110 can be easily controlled by the controller 310. [

On the other hand, the magnetron 115 generates and outputs a single microwave. The output microwaves are output into the cavity 134 through the second microwave transmitting unit 113.

Meanwhile, in the embodiment of the present invention, the microwave generator 110 for generating a plurality of microwaves and the magnetron 115 are used together.

The microwave generating unit 110 for generating a plurality of microwaves calculates the heating efficiency as described later, and varies the heating time according to the efficiency, thereby heating the object uniformly. However, the microwave generator 110 has a disadvantage in that the efficiency of the microwave generator 110 is lower than that of the magnetron 115 in comparison with the power consumption. On the other hand, the object of the magnetron 115 tends to be heated unevenly.

In the embodiment of the present invention, in the defrosting process in which uniform heating is prioritized during the cooking process, the heating process (boiling process) in which the microwave generating unit 110 is mainly operated and the heating efficiency is given priority over uniform heating during cooking, The magnetron 115 is mainly operated.

The control unit 310 controls the overall operation of the cooking apparatus. The control unit 310 controls the microwave generator 110 and the magnetron 115 to output microwaves when an operation signal of the cooking appliance is inputted through the operation unit 107. [ For example, as described above, the control unit 310 variably controls the operation of the microwave generator 110 and the magnetron 115 according to the cooking process of the object.

Hereinafter, the control unit 310 mainly describes the contents of controlling the microwave generation unit 110. FIG.

The control unit 310 outputs a frequency control signal and controls the frequency oscillation unit 332 to oscillate the corresponding frequency.

On the other hand, the control unit 310 can output frequency control signals of different voltage levels to output microwaves having a plurality of frequencies. Accordingly, the frequency oscillator 332 oscillates at a frequency corresponding to the voltage level of the input frequency control signal. The plurality of frequency control signals may be sequentially output from the control unit 310. [

The control unit 310 outputs a power control signal and controls the level adjusting unit 334 to output the corresponding power level.

On the other hand, the control unit 310 can output power control signals of different voltage levels in order to output microwaves having a plurality of powers. Accordingly, the level adjuster 334 outputs the corresponding power level according to the voltage level of the input power control signal. The plurality of power control signals may be sequentially output from the control unit 310. [

Also, the control unit 310 can compare the output power of the microwave and the reference power, and control the output power of the microwave to be constant based on the difference signal. For example, when the microwave generator 110 generates and outputs a plurality of microwaves, the controller 310 compares a plurality of microwave powers and reference powers, respectively, It is possible to control the power of the plurality of microwaves to be constant. This operation will be described with reference to FIG. 4 to be described later.

On the other hand, the control unit 310 can calculate the heating efficiency based on the microwave reflected into the cavity 134 without being absorbed by the object.

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. This heating efficiency calculation can be performed during the entire cooking interval.

Particularly, according to the embodiment of the present invention, it is more effective to perform the defrosting process during the whole cooking section.

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 control unit 310 generates and outputs a frequency control signal to vary the output period of the microwave according to the calculated heating efficiency. The frequency oscillator 332 oscillates at a frequency corresponding to the input frequency control signal.

The control unit 310 generates a 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. The detailed operation of the control unit 310 will be described later with reference to FIG.

On the other hand, the control unit 310 can control to output a microwave of the corresponding frequency only when the heating efficiency he calculated for each frequency is equal to or higher 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 control unit 310, the frequency oscillating unit 332, the amplifying unit 336, 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.

FIG. 4 is a view showing the inside of the control unit of FIG. 3. FIG.

The controller 310 includes a proportional-plus-integral controller (PI controller) 450 for controlling the power of the microwave output from the microwave generator 110 to be constant.

The microwave generator 110 receives the frequency control signal Sf and the level control signal Sp from the controller 310 and outputs the frequency control signal Sp to the frequency control signal Sf at the frequency oscillator 332, And outputs the level control signal Sp to a corresponding level in the level adjusting unit 334 so that the frequency oscillated by the amplifying unit 336 and the microwave of the set power level .

Normally, the output power Pt of the microwave is open loop control without feedback, so that it is not outputted with the power set by the control unit 310. [

Accordingly, when microwaves exceeding the set power level are output to the cavity 134, the power of the reflected microwaves may exceed the allowable range. As a result, a circuit element, for example, a DC converter Etc.) is likely to be damaged. Further, the accuracy of the calculated heating efficiency is also lowered.

Therefore, in the embodiment of the present invention, the power (Pt) of the output microwave is controlled to be uniform.

Meanwhile, the control unit 310 may include a storage unit (not shown) for storing the reference power Pref.

Accordingly, the control unit 310 compares the power Pt of the output microwave with the reference power Pref to calculate the difference signal Sd, and based on the calculated difference signal Sd, Control is performed.

Here, the proportional-plus-integral controller 450 controls the error of the difference signal Sd to be zero. The proportional integral control signal Sc is output to the level adjuster 334.

The level adjusting unit 334 receives the proportional integral control signal Sc and the level control signal Sp and outputs a signal of a constant level. As a result, the amplifying unit 336 outputs a microwave having a constant power.

In this manner, the microwave generator 110 outputs a microwave having a constant power by performing a closed loop control for feeding back the output power Pt of the microwave.

This closed loop control is also applicable to the case where a plurality of microwaves of different frequencies are output by the microwave generator 110. Accordingly, the microwave generator 110 outputs a plurality of microwaves of different frequencies having the same power.

FIG. 5 is a graph showing power according to a frequency of a microwave outputted from the cooking device of FIG.

4, the control unit 310 controls the power of a plurality of microwaves (corresponding frequencies f1, ..., f8) output from the microwave generating unit 110 to be (Pa). In particular, the plurality of microwaves output from the microwave generator 110 may be within a predetermined range around 915 MHz as described above.

On the other hand, the magnetron 115 outputs a single microwave. The frequency fn at this time may be approximately 2450 MHz as described above. It can be seen that the power Pb of the microwave output from the magnetron 115 is the power Pa of the plurality of microwaves output from the microwave generator 110. [ Accordingly, it is preferable to use the magnetron 115 having a higher power in the heating (boiling) process during the cooking process.

FIG. 6 is a graph showing the power according to the temperature of a microwave outputted from the cooking device of FIG. 3; FIG.

As described above, it is preferable that a plurality of microwaves output from the microwave generating unit 110 are used in the defrosting process Ph during the entire cooking process. This enables uniform thawing. In addition, as described above, it is possible to calculate the heating efficiency during the defrosting process and vary the output period of the microwave according to the calculated heating efficiency.

The single microwave output from the magnetron 115 is preferably used in the heating process Pf during the entire cooking process. Thus, the object can be efficiently heated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the 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;

FIG. 4 is a view showing the inside of the control unit of FIG. 3. FIG.

FIG. 5 is a graph showing power according to a frequency of a microwave outputted from the cooking device of FIG.

FIG. 6 is a graph showing the power according to the temperature of a microwave outputted from the cooking device of FIG. 3; FIG.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

110: microwave generating unit 112: first microwave transmitting unit

113: second microwave transmission unit 114: power supply unit

115: Magnetron 134: Cavity

310: control unit 332: frequency oscillation unit

334: Level adjuster 336: Amplifier

Claims (9)

A microwave generating unit for sequentially generating and outputting a plurality of microwaves having a plurality of frequencies so as to heat an object inside the cavity; And A magnetron for generating and outputting a single microwave to heat the object inside the cavity; And a controller for controlling the microwave generator and the magnetron according to the cooking process of the object, Wherein, An output period of microwaves sequentially output from the microwave generating unit based on the heating efficiency calculated by the microwave outputted sequentially in the cavity from the microwave generating unit and the microwave reflected in the cavity, And the frequency control signal is generated so as to vary the frequency of the microwave. delete The method according to claim 1, Wherein microwaves are output from the microwave generating unit more than the magnetron during a thawing process of the object. The method according to claim 1, Wherein microwaves are outputted from the magnetron more than the microwave generating unit during the heating process of the object. The method according to claim 1, Wherein the microwave- A frequency oscillator sequentially oscillating a corresponding frequency according to the frequency control signal sequentially input from the controller; And And an amplifier for amplifying the oscillated frequency signal and outputting a microwave for heating an object inside the cavity. 6. The method of claim 5, Wherein the microwave- And a directional coupler for transmitting the microwave into the cavity and receiving a microwave reflected from the cavity. delete The method of claim 1, wherein Wherein, Wherein the frequency control signal is generated so that the output period of the microwave becomes shorter as the calculated heating efficiency becomes higher. The method according to claim 1, A first microwave transmitter for transmitting a plurality of microwaves from the microwave generator into the cavity; And And a second microwave transmitter for transmitting the microwave from the magnetron to the inside of the cavity.

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