KR101620448B1 - A cooking apparatus using microwave - Google Patents

Abstract

The present invention relates to a microwave-assisted cooking appliance. The microwave-assisted cooking apparatus according to the present invention includes a microwave generating unit for generating and outputting a plurality of microwaves for heating an object in a cavity, and a plurality of microwaves reflected from the cavity, And sets a heating time for each microwave in the heating section in accordance with the calculated heating efficiency. Thus, it is possible to shorten the heating time for the microwave having a high heating efficiency and to transmit the uniform power to the inside of the cavity by extending the heating time for the microwave having a low heating efficiency.

Cooking equipment, Microwave, Heating efficiency, Heating time, Variable 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 delivering uniform power to an interior of a cavity.

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.

The present invention provides a microwave-assisted cooking device capable of shortening a heating time for a microwave having a high heating efficiency and a uniform heating power for a microwave having a low heating efficiency by extending the heating time. There is a purpose.

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 control unit for calculating the heating efficiency for each of the plurality of microwaves based on the reflected microwave and setting the heating time for each microwave in the heating period according to the calculated heating efficiency.

The control unit sets the heating time of the first microwave to be shorter than the heating time of the second microwave when the first microwave of the plurality of microwaves has a heating efficiency higher than that of the second microwave.

The microwave generator outputs a power magnitude for each of the plurality of microwaves constantly during the heating period.

According to the present invention, heating time is shortened for a microwave having a high heating efficiency and a heating time is extended for a microwave having a low heating efficiency, so that a uniform power can be delivered to the inside of the cavity.

Further, according to the present invention, it is not necessary to separately provide a device for power control by making the power intensity constant during the heating section using the microwave, thereby reducing the cost.

Simultaneous heat generation of each part of the food makes it possible to uniformly cook foods having various sizes and shapes.

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 the 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 body 102 is provided with a cavity 134 having an accommodation space of a predetermined size so that the object to be heated 140, for example, food can be received and cooked by microwave.

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 to this, and an antenna may be coupled to the end Do. 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. The overall operation of the cooking apparatus 100 can be performed by a control unit (not shown). The control unit (not shown) will be described with reference to the following drawings.

FIG. 3 is a block diagram schematically showing the inside of the cooking apparatus of FIG. 1; FIG. 4 is a diagram showing changes in frequency during a cooking process including a scan period and a heating period.

Referring to the drawings, a cooking apparatus 100 according to an embodiment of the present invention includes a microwave generation unit 110 and a control unit 310. Further, the cooking apparatus 100 may further include a microwave transmitting unit 112.

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 adjusting unit 334 outputs the microwave at the corresponding power by the power control signal from the control unit 310. [ 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 level adjuster 334 can constantly output the power level for each of the plurality of microwaves by receiving the same power control signal from the controller 310 for each microwave during the heating period.

In addition, since the power intensity is constant during the heating period using the microwave, the level control unit 334 for power control may not be separately provided.

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 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 that is not absorbed by the object and is reflected may be input to the directional coupler 338 through the microwave transfer unit 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. [

The control unit 310 controls the overall operation of the cooking apparatus. When the operation signal of the cooking appliance is input through the operation unit 107, the control unit 310 controls the microwave generation unit 110 to output microwaves.

The control unit 310 calculates the heating efficiency for each of the plurality of microwaves based on the microwave reflected from the inside of the cavity among the microwaves output by the microwave generating unit 110, Accordingly, the heating time for each microwave is set during the heating period.

At this time, when the first microwave of the plurality of microwaves has a higher heating efficiency than the second microwave, the controller 310 sets the heating time of the first microwave to be shorter than the heating time of the second microwave.

Specifically, 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.

At this time, the control unit 310 may output the same power control signal to each microwave during the heating period. Also, the level adjuster 334 can output a constant power level according to the input power control signal.

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 by the cavity 134, and he represents the heating efficiency of the microwave. That is, the heating efficiency he becomes smaller as the reflected microwave power increases.

On the other hand, when a plurality of microwaves are emitted into the cavity 134, the controller 310 calculates the heating efficiency he for each frequency of a plurality of microwaves. It is preferable that the heating efficiency calculation is performed in the scan period during the entire cooking interval and during the heating interval.

Meanwhile, it is possible that the entire cooking interval is performed after the scan interval is performed, and the heating interval is performed while the scan interval is being performed. It is also possible to perform it repeatedly during the whole cooking section.

That is, the control unit 310 sequentially emits a plurality of microwaves to the heating object 140 in the cavity 134 during the cooking interval set by the user, and outputs the heating efficiency he Can be calculated.

Thereafter, the control unit 310 adjusts the emission time of the microwave for each frequency in the heating section, which is the actual cooking section, according to the calculated heating efficiency (he). That is, the higher the heating efficiency (he), the smaller the release time 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.

On the other hand, the control unit 310 can control the microwave of the corresponding frequency to be emitted in the heating section 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.

On the other hand, the above-described emission of the plurality of microwaves can be sequentially performed with time.

On the other hand, the control unit 310 can also control the display unit 105 to display the operation state of the cooking appliance. For example, if the current cooking interval is the current cooking interval, it can be displayed through the display unit 105, and if it is an actual heating interval, it can also be displayed. In addition, various display functions such as displaying the remaining time of the entire cooking section and the like can be performed.

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. Meanwhile, the power supply unit 114 may generate and supply a predetermined control power for controlling the control unit (not shown).

Meanwhile, the control unit 310 and the microwave generating unit 110 may be implemented as a single module. That is, the control unit 310 and the microwave generating unit 110 may be integrated on a single substrate.

The process of controlling the heating time by frequency according to the present invention will now be described with reference to the above configuration.

The controller 310 outputs a frequency control signal for sweeping microwaves of various frequencies to the frequency oscillator 332 of the microwave generator 110 during the scan period.

The frequency oscillator 332 generates a plurality of microwaves according to the frequency control signal input from the controller 310.

The level adjusting unit 334 adjusts the level corresponding to the amplitude of the microwave generated by the frequency oscillating unit 332 according to the power control signal input from the control unit 310. [ At this time, the power control signal output from the controller 500 to the level controller 334 may be provided as the same signal for all the microwaves used in the sweep process.

The amplifying unit 336 amplifies the level-adjusted microwave, and the isolation unit (not shown) provides the amplified microwave to the directional coupler 520. The directional coupler 338 amplifies the microwave, To the microwave transmitting unit 112. The microwave transmitting unit 112 is a microwave transmitting unit.

The microwave transmitting unit 112 outputs the microwave provided by the directional coupler 520 to the cavity 134.

On the other hand, when a part of the output microwave is reflected from the cavity 134, the directional coupler 338 provides the reflected microwave to a DC converter (not shown).

DC converter (not shown) outputs a feedback signal obtained by converting a part of the microwave reflected from the cavity 134 to DC to the controller 310.

The control unit 310 calculates the heating efficiency for each of the plurality of microwaves based on the input feedback signal. At this time, the controller 310 can determine that the heating efficiency is high when the feedback signal for each microwave is small.

In addition, the control unit 310 variably controls the heating time for each microwave, that is, the emission time for each microwave during the heating period, according to the heating efficiency for each of the calculated microwaves. At this time, the controller 310 allows the heating time to be shortened for the microwave having a high heating efficiency and the heating time to be long for the microwave having a low heating efficiency.

For example, if the heating efficiency for the microwave of the frequency f5 is low as a result of calculation of the heating efficiency, the controller 310 controls the heating time for the microwave of the frequency f5 to be relatively long during the heating period Th shown in FIG. , And when the heating efficiency for the microwave of the frequency f3 is high, the heating time for the microwave of the frequency f3 is relatively short during the heating period (Th).

4 may be determined by the operation of the user or may be determined according to the type of the object in the cavity 134 and may be determined between the scan period Ts and the heating period Th, There may be a gap time, and the heating period Th may be maintained relatively longer than the scan period Ts. In addition, the scan period and the heating period can be repeatedly performed during the cooking process using microwaves.

That is, the control unit 310 provides a frequency control signal to the frequency oscillation unit 332 of the microwave generation unit 110 for generating a microwave of the corresponding frequency for a short time for a microwave having a high heating efficiency, For this low microwave, the frequency control signal for generating the microwave of the corresponding frequency for a long time can be outputted to the frequency oscillator 332 of the microwave generator 110.

The frequency oscillator 332 generates a corresponding microwave in accordance with the frequency control signal provided from the controller 310.

The level adjusting unit 334 adjusts the level corresponding to the amplitude of the microwave generated by the frequency oscillating unit 332 according to the power control signal provided from the control unit 310. At this time, the power control signal provided by the controller 310 to the level controller 334 may be provided as the same signal for all the microwaves used in the heating section.

The amplifying unit 336 amplifies the level-adjusted microwave, and the isolation unit (not shown) provides the amplified microwave to the directional coupler 338, and the directional coupler 338 amplifies the microwave, To the microwave transfer unit 112 and the microwave transfer unit 112 outputs the microwave provided by the directional coupler 338 to the cavity 134.

Accordingly, it is possible to shorten the heating time for the microwave having a high heating efficiency and to deliver a uniform power to the inside of the cavity by extending the heating time for the microwave having a low heating efficiency.

FIG. 5 is a flowchart illustrating a control method of a microwave-assisted cooking apparatus according to the present invention. FIG. 6A is a diagram illustrating heating efficiency by frequency, and FIG.

Referring to FIG. 5, the control unit of the microwave cooker according to the present invention sweeps microwaves of various frequencies to detect the heating efficiency for each frequency as shown in FIG. 6A (S502).

That is, the control unit sequentially outputs the frequency control signal to the frequency oscillation unit of the microwave generation unit, and the frequency oscillation unit generates the microwave of the frequency according to the frequency control signal output from the control unit.

The level controller of the microwave generator adjusts the level corresponding to the amplitude of the microwave generated by the frequency oscillator according to the power control signal output from the controller.

The amplification unit in the microwave generation unit amplifies the level-controlled microwave, and the isolation unit in the microwave generation unit provides the amplified microwave to the directional coupling unit in the microwave generation unit.

The directional coupler provides the microwave transmitted by the isolator to the microwave transmitter, and the microwave transmitter outputs the microwave provided by the directional coupler to the cavity.

When a part of the microwave outputted from the cavity is reflected by the cavity, the directional coupler provides the reflected microwave to the DC converter, and the DC converter converts the feedback signal obtained by converting a part of the provided microwave into DC, .

The control unit calculates the heating efficiency for each of the plurality of microwaves based on the provided feedback signal. At this time, the controller can calculate that the heating efficiency is high when the feedback signal for each microwave is small.

Meanwhile, the control unit may store the calculated frequency-based heating efficiency through the storage unit (S504).

In addition, the controller determines the heating time for each microwave according to the heating efficiency for each of the detected microwaves (S506). That is, the control unit can shorten the heating time for the microwave having a high heating efficiency and can increase the heating time for a microwave having a low heating efficiency.

For example, referring to Figs. 6A and 6B, since the heating efficiency for the microwave of the frequency f2 is lower than the heating efficiency for the microwave of the frequency f6, the control unit calculates the heating time T2 for the microwave of the frequency f2 can be determined to be relatively longer than the heating time (T6) for the microwave of frequency f6. In addition, there may be a predetermined gap time between heating times by frequency.

At this time, the controller can selectively use only the microwaves (f2, f5, f6, f7) having the calculated heating efficiency equal to or higher than the threshold value for the heating process.

In addition, the control unit variably controls the heating time for each frequency according to the heating time for each of the microwaves determined as described above (S508).

That is, the control unit outputs a frequency control signal for generating a microwave of the corresponding frequency to the frequency oscillation unit of the microwave generation unit for a short time for a microwave having a high heating efficiency, and for a long time A frequency control signal for generating a microwave of the frequency can be output to the frequency oscillation unit of the microwave generation unit.

The frequency oscillation unit in the microwave generation unit generates the microwave according to the frequency control signal input from the control unit.

The level controller in the microwave generator adjusts the level corresponding to the amplitude of the microwave generated by the frequency oscillator according to the power control signal input from the controller. At this time, the power control signal provided by the control unit to the level adjusting unit may be provided as the same signal for all the microwaves used in the heating process.

The amplifying unit in the microwave generating unit amplifies the level-controlled microwave, the isolating unit in the microwave generating unit provides the amplified microwave to the directional coupling unit in the microwave generating unit, and the directional coupling unit includes the microwave To the microwave transmitting unit, and the microwave transmitting unit outputs the microwave provided by the directional coupling unit to the cavity.

Accordingly, heating time is shortened for a microwave having a high heating efficiency and a heating time is extended for a microwave having a low heating efficiency, so that uniform power can be transmitted to the inside of the cavity to uniformly heat the inside of the cavity.

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.

2 is a sectional view of the cooking appliance of Fig.

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

FIG. 4 is a graph showing changes in frequency during a cooking process including a scan period and a heating period; FIG.

FIG. 5 is a flowchart illustrating a method of controlling a microwave cooker according to the present invention. FIG.

6A is a diagram showing heating efficiency by frequency.

6B is a diagram showing a heating time by frequency.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

310: control unit 110: microwave generating unit

112: microwave transmission unit 134: cavity

Claims (12)

A microwave generating unit for generating and outputting a plurality of microwaves for heating an object inside the cavity; And The heating efficiency for each of the plurality of microwaves is calculated on the basis of a microwave reflected from the inside of the cavity of the output microwaves, and the first microwave of the plurality of microwaves is heated more efficiently than the second microwave The control unit sets the heating time of the first microwave to be shorter than the heating time of the second microwave; And a microwave-type cooking device. delete The method according to claim 1, Wherein the microwave- And a power level for each of the plurality of microwaves is constantly output during the heating period. The method according to claim 1, Wherein, Wherein during the heating period, the same power control signal for each microwave is provided to the microwave generator. The method according to claim 1, Wherein the microwave- And sequentially generating and outputting a plurality of microwaves for heating an object in the cavity. The method according to claim 1, Wherein, Wherein only the microwave whose calculated heating efficiency is equal to or higher than the reference efficiency is selected and the heating time for each microwave is set during the heating period. The method according to claim 1, And a microwave transmitter for transmitting the microwave generated by the microwave generator to the inside of the cavity. The method according to claim 1, Wherein, Wherein the heating efficiency is calculated in a scan period during a cooking process using a microwave including a scan period and a heating period. The method according to claim 1, Wherein the microwave- A frequency oscillating unit for oscillating the frequency, and an amplifying unit for amplifying the microwave having the oscillated frequency. 10. The method of claim 9, The microwave generator may further include a level controller, Wherein the level regulator outputs a power level for each of the plurality of microwaves constantly during the heating period by the same power control signal. 10. The method of claim 9, The microwave generating unit may further include a directional coupler, Wherein the directional coupler provides the microwave to the microwave transmitter and provides the microwave reflected from the cavity to the controller. 10. The method of claim 9, The microwave generator may further include a DC converter, Wherein the DC converter converts the microwave reflected from the inside of the cavity into DC, and outputs the converted DC to the controller.

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