JP6433416B2 - High frequency irradiation apparatus, high frequency irradiation system, and high frequency irradiation method - Google Patents

Description

  The present invention relates to a high frequency irradiation apparatus, a high frequency irradiation system, and a high frequency irradiation method for heating an object to be heated by irradiating a high frequency.

  As a conventional high-frequency irradiation device, there is one provided with a magnetron oscillator that can irradiate microwaves (see, for example, Patent Document 1). In the prior art described in Patent Document 1, the output of a magnetron oscillator that irradiates microwaves to an object to be heated installed in a heating chamber is distributed and the phase of the output is controlled. Irradiate waves. By comprising in this way, an to-be-heated material can be made to absorb energy efficiently, As a result, a to-be-heated material can be heated.

JP 2010-92795 A

  Here, when the object to be heated is irradiated with high frequency, the frequency of the high frequency at which the object to be heated easily absorbs energy (hereinafter referred to as the energy absorption frequency) is accompanied by a change in physical properties of the object to be heated by heating. Pay attention to change. The prior art described in Patent Document 1 does not pay attention to such a point, and does not correspond to a change in energy absorption frequency accompanying a change in physical properties of an object to be heated due to heating. As a result, there is a problem that the heating efficiency decreases as the object to be heated is heated.

  The present invention has been made in order to solve the above-described problems, and is capable of efficiently heating an object to be heated even when physical properties of the object to be heated are changed due to heating. An object is to obtain an irradiation apparatus, a high-frequency irradiation system, and a high-frequency irradiation method.

  The high frequency irradiation apparatus according to the present invention includes an oscillator that generates a high frequency, a first detection unit that detects input power input when the output of the oscillator is irradiated, and an oscillator according to a detection result of the first detection unit. A frequency / phase control unit that controls the output frequency of the output, and a second detection unit that detects a frequency change amount that is a change amount per unit time of the output frequency controlled by the frequency / phase control unit, The frequency / phase control unit controls the output phase of the oscillator according to the detection result of the second detection unit.

  The high frequency irradiation system according to the present invention includes a plurality of high frequency irradiation devices.

  The high-frequency irradiation method according to the present invention includes a first detection step for detecting input power input when an output of an oscillator that generates a high frequency is applied, and an output of the oscillator according to a detection result in the first detection step. A frequency / phase control step for controlling the frequency, and a second detection step for detecting a frequency change amount that is a change amount per unit time of the output frequency controlled in the frequency / phase control step. In the phase control step, the output phase of the oscillator is controlled in accordance with the detection result in the second detection step.

  According to the present invention, the input power input when the output of the oscillator that generates a high frequency is irradiated is detected, the output frequency of the oscillator is controlled according to the detection result, and the output frequency of the controlled oscillator is controlled. The frequency change amount per unit time is detected, and the output phase of the oscillator is controlled according to the detection result. As a result, a high-frequency irradiation apparatus, a high-frequency irradiation system, and a high-frequency irradiation method that can efficiently heat the object to be heated can be obtained even when physical properties of the object to be heated are changed due to heating.

It is a block diagram which shows the high frequency irradiation apparatus in Embodiment 1 of this invention. In Embodiment 1 of this invention, it is a schematic diagram for demonstrating the relationship between the output frequency of a voltage controlled oscillator, and the reflected wave when the to-be-heated material is irradiated with the output wave of a voltage controlled oscillator. In Embodiment 1 of this invention, it is a graph which shows the relationship between the temperature of a to-be-heated material, and an energy absorption frequency. In Embodiment 1 of this invention, it is a graph which shows the relationship between the irradiation time of a to-be-heated material, and an energy absorption frequency. In Embodiment 1 of this invention, it is a schematic diagram which shows the relationship between the position of the to-be-heated object in a heating furnace, and the output phase of the voltage controlled oscillator 2. FIG. It is a block diagram which shows the high frequency irradiation apparatus in Embodiment 2 of this invention. It is a block diagram which shows the phase-synchronization circuit which is an example of the circuit structure of the frequency and phase control part in Embodiment 2 of this invention. It is a block diagram which shows the high frequency irradiation system provided with two or more high frequency irradiation apparatuses in Embodiment 1 or 2 of this invention.

  Hereinafter, a high-frequency irradiation apparatus, a high-frequency irradiation system, and a high-frequency irradiation method according to the present invention will be described with reference to the drawings according to a preferred embodiment. In the description of the drawings, the same portions or corresponding portions are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a high-frequency irradiation device 1 according to Embodiment 1 of the present invention. In addition, in FIG. 1, the antenna 7 connected to the high frequency irradiation apparatus 1 is also shown in figure.

  1 includes a voltage-controlled oscillator 2, a frequency / phase control unit 3 having a frequency control unit 31 and a phase control unit 32, a first detection unit 4, and a second detection unit 5. And a circulator 6.

  The output of the voltage controlled oscillator 2 that generates a high frequency is irradiated from the antenna 7 via the circulator 6. The reflected power of the reflected wave received by the antenna 7 when the output of the voltage controlled oscillator 2 is irradiated via the antenna 7 is input to the first detection unit 4 via the circulator 6.

  The first detection unit 4 detects the reflected power and outputs the detection result to the frequency control unit 31. The frequency control unit 31 controls the output frequency of the voltage controlled oscillator 2 according to the detection result by the first detection unit 4. Specifically, the frequency control unit 31 outputs a DC voltage for controlling the output frequency of the voltage controlled oscillator 2 to the voltage controlled oscillator 2.

  The second detection unit 5 detects a frequency change amount that is a change amount per unit time of the output frequency of the voltage controlled oscillator 2 controlled by the frequency control unit 31, and outputs the detection result to the phase control unit 32. To do. The phase control unit 32 controls the output phase of the voltage controlled oscillator 2 according to the detection result by the second detection unit 5.

  Next, the operation of the high frequency irradiation apparatus according to the first embodiment will be further described. The output of the voltage controlled oscillator 2 is irradiated from the antenna 7 via the circulator 6 as described above.

  Here, the relationship between the output frequency of the voltage controlled oscillator 2 and the reflected wave when the output of the voltage controlled oscillator 2 is irradiated on the object to be heated will be described with reference to FIG. FIG. 2 is a schematic diagram for explaining the relationship between the output frequency of the voltage controlled oscillator 2 and the reflected wave when the output wave of the voltage controlled oscillator 2 is irradiated to the object to be heated in the first embodiment of the present invention. FIG.

  As shown in FIG. 2, when the output frequency of the voltage controlled oscillator 2 is a frequency suitable for energy absorption, that is, the energy absorption frequency, the irradiated high frequency energy is easily absorbed by the object to be heated. The reflection of is small. In this case, the reflected power of the reflected wave is small. In addition, since the irradiated high frequency energy is easily absorbed by the object to be heated, the object to be heated can be efficiently heated.

  On the other hand, when the output frequency of the voltage controlled oscillator 2 is not a frequency suitable for energy absorption, that is, the energy absorption frequency, the irradiated high frequency energy is difficult to be absorbed by the object to be heated, and as a result, the reflection of high frequency is large. . In this case, the reflected power of the reflected wave is large. Further, since the irradiated high-frequency energy is not easily absorbed by the object to be heated, the efficiency of heating the object to be heated cannot be improved.

  Therefore, the frequency control unit 31 controls the output frequency of the voltage controlled oscillator 2 so that the reflected power detected by the first detection unit 4 becomes the first set value. The first set value is a value of 0 or more set in advance. The smaller the first set value, the smaller the reflected power, and the output frequency can be brought closer to the energy absorption frequency.

  Specifically, the first detection unit 4 converts the detected reflected power into a DC voltage, and outputs a DC voltage corresponding to the detected reflected power to the frequency control unit 31 as a detection result. The frequency control unit 31 controls the output frequency of the voltage controlled oscillator 2 according to the output voltage value of the first detection unit 4 so that the output voltage value becomes the first set value. Further, if the first set value is appropriately set, the output frequency of the voltage controlled oscillator 2 can be made equal to the energy absorption frequency.

  Here, the point that the energy absorption frequency changes due to the temperature rise accompanying the heating of the object to be heated will be described with reference to FIG. FIG. 3 is a graph showing the relationship between the temperature of the object to be heated and the energy absorption frequency in the first embodiment of the present invention.

  As shown in FIG. 3, the physical property value of the object to be heated changes due to the temperature rise accompanying the heating of the object to be heated, so that the energy absorption frequency changes. Specifically, the energy absorption frequency increases as the temperature of the object to be heated increases.

  On the other hand, as described above, the output frequency of the voltage controlled oscillator 2 is controlled in accordance with the detection result of the first detection unit 4, so that the output frequency of the voltage controlled oscillator 2 changes the energy absorption frequency. Follow. Therefore, it is possible to cope with a change in energy absorption frequency accompanying a change in physical property value of the object to be heated.

  As described above, by configuring the output frequency of the voltage controlled oscillator 2 according to the detection result by the first detection unit 4, regardless of the change in the energy absorption frequency accompanying the change in the physical property value of the object to be heated, The object to be heated can be efficiently heated.

  As described above, the second detection unit 5 detects a frequency change amount that is a change amount per unit time of the output frequency of the voltage controlled oscillator 2, and outputs the detection result to the phase control unit 32. Specifically, the second detection unit 5 detects the output frequency of the voltage-controlled oscillator 2 at a constant time interval. When the time interval is Δt and the change in the output frequency at Δt is Δf, the second detection unit 5 Frequency change amount (= Δf / Δt) is detected, and the frequency change amount is output to the phase control unit 32.

  Here, when the frequency control unit 31 is configured to output a DC voltage for controlling the output frequency of the voltage controlled oscillator 2 to the voltage controlled oscillator 2, a change in the output voltage value of the frequency control unit 31; The change of the output frequency of the voltage controlled oscillator 2 is equivalent.

  Therefore, the second detection unit 5 detects the output voltage value of the frequency control unit 31 at regular time intervals, detects the voltage change amount per unit time of the output voltage value as the frequency change amount, and the voltage The amount of change is output to the phase control unit 32 as a detection result.

  Here, the relationship between the frequency change amount and the heating rate will be described with reference to FIG. FIG. 4 is a graph showing the relationship between the irradiation time of the object to be heated and the energy absorption frequency in the first embodiment of the present invention.

  As shown in FIG. 4, as the change in energy absorption frequency per unit time of irradiation time increases, the heating proceeds rapidly and the heating rate is large. In addition, a large voltage change amount per unit time of the output voltage value of the frequency control unit 31 is equivalent to a large frequency change amount, which means that the heating rate is large.

  Therefore, the phase control unit 32 controls the output phase of the voltage controlled oscillator 2 so that the absolute value of the frequency change detected by the first detection unit 4 becomes the second set value. The second set value is a value that is set to 0 or more in advance. The larger the second set value, the higher the heating rate.

  Here, the relationship between the position of the object to be heated in the heating furnace and the output phase of the voltage controlled oscillator 2 will be described with reference to FIG. FIG. 5 is a schematic diagram showing the relationship between the position of the object to be heated 10 in the heating furnace 9 and the output phase of the voltage controlled oscillator 2 in the first embodiment of the present invention.

  As shown in FIG. 5, voltage control is performed so that the position where the object to be heated 10 exists in the heating furnace 9 and the position of the maximum amplitude of the high frequency irradiated from the antenna 7, that is, the position where the electric field is high. It is effective to control the output phase of the oscillator 2. By controlling the phase in this way, the heating rate can be increased. Therefore, the heating rate can be improved by appropriately setting the second set value capable of realizing such phase control.

  In the first embodiment, the case where the input power input when the output of the voltage controlled oscillator 2 is irradiated is the reflected power of the reflected wave received by the antenna 7, is illustrated. It is not limited to. That is, instead of the reflected power, the temperature of the object to be heated is measured by a thermocouple, and a direct current or a DC voltage corresponding to the temperature of the object to be heated is input as input power from the thermocouple to the first detection unit 4. You may comprise.

  In the first embodiment, the voltage controlled oscillator 2 is used as an oscillator for generating a high frequency. However, the present invention is not limited to this. For example, an yttrium / iron / garnet oscillator is used instead of the voltage controlled oscillator 2. A current-controlled oscillator such as In this case, the output of the frequency control unit 31 is configured to be a direct current instead of a direct current voltage. The second detection unit 5 is configured to detect the amount of change per unit time of the output current value of the frequency control unit 31 or the voltage value corresponding to the output current value as the frequency change amount. .

  As described above, the frequency / phase control unit 3 controls the output frequency by outputting a DC voltage or a DC current for controlling the output frequency of the oscillator to the oscillator according to the type of the oscillator to be used.

  As described above, according to the first embodiment, the input power input when the output of the oscillator that generates a high frequency is irradiated is detected, and the output frequency of the oscillator is controlled and controlled according to the detection result. A frequency change amount per unit time of the output frequency of the oscillator is detected, and the output phase of the oscillator is controlled according to the detection result.

  In the above configuration, since the output frequency of the oscillator is controlled so that the input power becomes small, the output frequency of the oscillator can be set to the energy absorption frequency, and the output phase of the oscillator can be set to increase the frequency change amount. Since it is controlled, the heating rate of the object to be heated can be increased. Therefore, even when the physical property change of the heated object occurs due to heating, the heated object can be efficiently heated. That is, it is possible to cope with changes in physical properties of an object to be heated due to heating or the like, and as a result, energy efficient heating and high speed heating are possible.

Embodiment 2. FIG.
In the first embodiment of the present invention, a high frequency irradiation apparatus 1 including a frequency / phase control unit 3 having a configuration different from that of the first embodiment will be described. In the second embodiment, description of points that are the same as those of the first embodiment will be omitted, and points different from the first embodiment will be mainly described.

  FIG. 6 is a configuration diagram showing the high-frequency irradiation device 1 according to Embodiment 2 of the present invention. In FIG. 6, an antenna 7 connected to the high-frequency irradiation device 1 is also illustrated. The high frequency irradiation apparatus 1 in FIG. 6 includes a voltage controlled oscillator 2, a frequency / phase control unit 3, a first detection unit 4, a second detection unit 5, and a circulator 6. Here, the frequency / phase control unit 3 in the second embodiment is configured by a phase synchronization circuit 8 to be described later.

  Next, a phase locked loop (PLL) 8 which is an example of a circuit configuration of the frequency / phase control unit 3 in the second embodiment will be described with reference to FIG. FIG. 7 is a configuration diagram showing a phase synchronization circuit 8 which is an example of a circuit configuration of the frequency / phase control unit 3 according to the second embodiment of the present invention.

  7 includes a coupler 81, a frequency divider 82, a crystal oscillator 83, a phase shifter 84, a phase comparator 85, and a loop filter 86. The frequency divider 82 divides the output of the voltage controlled oscillator 2 by N. The crystal oscillator 83 is an example of a reference oscillator that generates a reference frequency. The phase shifter 84 shifts the output of the crystal oscillator 83.

  The phase comparator 85 compares the output of the phase shifter 84 with the output of the frequency divider 82 and outputs a DC voltage to the voltage controlled oscillator 2 via the loop filter 86 according to the phase difference. As described in the first embodiment, when a current controlled oscillator is used instead of the voltage controlled oscillator 2, the phase comparator 85 controls the direct current instead of the direct current voltage via the loop filter 86. Output to the oscillator 2.

  Next, the operation of the phase synchronization circuit 8 will be further described. The output of the voltage controlled oscillator 2 is input from the coupling terminal of the coupler 81 to the frequency divider 82. The output of the frequency divider 82 is a frequency obtained by dividing the output frequency of the voltage controlled oscillator 2 by N.

  The output of the frequency divider 82 and the output of the crystal oscillator 83 phase-shifted by the phase shifter 84 are phase-compared by the phase comparator 85, and the direct current output from the phase comparator 85 according to the phase difference. Is applied as a DC voltage to the frequency control terminal of the voltage controlled oscillator 2 through the loop filter 86.

  At this time, since the phase comparator 85 is controlled to eliminate the phase difference, the output frequency of the voltage controlled oscillator 2 is equal to the product of the output frequency of the crystal oscillator 83 and the frequency division number N of the frequency divider 82. Become.

  The first detection unit 4 converts the reflected power input from the antenna 7 into a DC voltage, and outputs a DC voltage corresponding to the detected reflected power to the phase synchronization circuit 8 as a detection result. The phase synchronization circuit 8 controls the frequency division number N of the frequency divider 82 so that the output voltage value of the first detection unit 4 becomes the first set value. By controlling in this way, the output frequency of the voltage controlled oscillator 2 changes, and the output frequency can be brought close to the energy absorption frequency.

  The second detection unit 5 detects the output voltage value of the loop filter 86 at regular time intervals, detects the voltage change amount per unit time of the output voltage value as the frequency change amount, and determines the voltage change amount. The detection result is output to the phase synchronization circuit 8. The phase synchronization circuit 8 controls the phase shift amount of the phase shifter 84 so that the voltage change amount detected by the second detection unit 5 becomes the second set value. By controlling in this way, the phase difference of the phase comparator 85 changes with the change of the phase shift amount of the phase shifter 84. Further, since the output phase of the voltage controlled oscillator 2 is synchronized with such a change, the output phase of the voltage controlled oscillator 2 can be controlled.

  As described above, according to the second embodiment, the frequency / phase control unit is configured by a phase synchronization circuit compared to the configuration of the first embodiment. Specifically, in the phase locked loop circuit, the output frequency of the oscillator is controlled by controlling the N fraction of the frequency divider according to the detection result of the first detector, and the change per unit time of the output of the loop filter The output phase of the oscillator is controlled by controlling the phase shift amount of the phase shifter according to the detection result by the second detection unit that detects the amount as the frequency change amount. Thereby, the same effect as in the first embodiment can be obtained.

  As shown in FIG. 8, a plurality of high-frequency irradiation apparatuses 1 according to the first or second embodiment may be provided, and a high-frequency irradiation system in which the plurality of high-frequency irradiation apparatuses 1 can operate in conjunction with each other may be configured. FIG. 8 is a configuration diagram showing a high-frequency irradiation system including a plurality of high-frequency irradiation apparatuses 1 according to Embodiment 1 or 2 of the present invention.

  As shown in FIG. 8, it may be configured so that the high frequency irradiated from the antenna 7 to the object to be heated 10 is synthesized in the same phase, and by this configuration, the electric field can be further increased, As a result, more effective heating is possible. In addition, an active phased array may be applied to a high-frequency irradiation system including a plurality of high-frequency irradiation apparatuses 1, and similarly, a high electric field can be realized and effective heating can be achieved.

  DESCRIPTION OF SYMBOLS 1 High frequency irradiation apparatus, 2 Voltage control oscillator, 3 Frequency / phase control part, 4 1st detection part, 5 2nd detection part, 6 Circulator, 7 Antenna, 8 Phase synchronization circuit, 9 Heating furnace, 10 To-be-heated object 31 frequency control unit, 32 phase control unit, 81 coupler, 82 frequency divider, 83 crystal oscillator, 84 phase shifter, 85 phase comparator, 86 loop filter.

Claims (8)

An oscillator that generates high frequencies;
A first detector for detecting input power input when the output of the oscillator is irradiated;
A frequency / phase control unit for controlling the output frequency of the oscillator according to a detection result by the first detection unit;
A second detection unit that detects a frequency change amount that is a change amount per unit time of the output frequency controlled by the frequency / phase control unit;
With
The frequency / phase controller is
A high frequency irradiation apparatus that controls an output phase of the oscillator according to a detection result by the second detection unit. The first detection unit includes:
The high frequency irradiation apparatus according to claim 1, wherein when the output of the oscillator is irradiated through an antenna, the reflected power of a reflected wave received by the antenna is detected as the input power. The frequency / phase controller is
Controlling the output frequency so that the input power detected by the first detection unit becomes a first set value;
The high-frequency irradiation apparatus according to claim 1, wherein the output phase is controlled such that an absolute value of the frequency change amount detected by the second detection unit becomes a second set value. The frequency / phase controller is
The output frequency is controlled by outputting a DC voltage or a DC current for controlling the output frequency to the oscillator,
The second detection unit includes:
The high frequency irradiation apparatus according to any one of claims 1 to 3, wherein a change amount per unit time of the DC voltage or the DC current, which is an output of the frequency / phase control unit, is detected as the frequency change amount. The high-frequency irradiation apparatus according to claim 1, wherein the frequency / phase control unit includes a phase synchronization circuit. The phase synchronization circuit includes:
A reference oscillator for generating a reference frequency;
A phase shifter for phase shifting the output of the reference oscillator;
A frequency divider for dividing the output of the oscillator by N;
A phase comparator that compares the phase of the output of the phase shifter and the output of the frequency divider, and outputs a DC voltage or DC current to the oscillator via a loop filter according to the phase difference;
With
The second detection unit detects a change amount per unit time of the output of the loop filter as the frequency change amount,
The phase synchronization circuit is
According to the detection result by the first detection unit, the output frequency is controlled by controlling the frequency division number N of the frequency divider,
The high frequency irradiation apparatus according to claim 5, wherein the output phase is controlled by controlling a phase shift amount of the phase shifter according to a detection result by the second detection unit. A high-frequency irradiation system comprising a plurality of the high-frequency irradiation devices according to any one of claims 1 to 6. A first detection step of detecting input power input when an output of an oscillator that generates a high frequency is irradiated;
A frequency / phase control step for controlling the output frequency of the oscillator according to the detection result in the first detection step;
A second detection step of detecting a frequency change amount that is a change amount per unit time of the output frequency controlled in the frequency / phase control step;
With
In the frequency / phase control step,
A high frequency irradiation method of controlling an output phase of the oscillator according to a detection result in the second detection step.

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