JP5092863B2 - Microwave processing equipment - Google Patents

Description

  The present invention relates to a microwave processing apparatus including a microwave generation unit configured using a semiconductor element.

  A conventional microwave processing apparatus of this type has a semiconductor oscillating unit, a plurality of amplifying units that amplify the output of the oscillating unit, a heating chamber, and an impedance detecting unit that detects the impedance of the power feeding unit. There are some (see, for example, Patent Document 1). The oscillation frequency is controlled based on the detection result of the impedance detection unit, thereby enabling stable cooking without unevenness.

  Some have a microwave heating power source that can vary the oscillation frequency, an antenna that radiates microwave power to the heating chamber, and a detector that detects reflected power from the antenna (see, for example, Patent Document 2). Then, the oscillation frequency of the power source that minimizes the reflected power is tracked, and the power source is driven in the vicinity thereof, so that it can always be driven with the maximum power efficiency.

A semiconductor oscillating unit; a distributing unit that divides the output of the semiconductor oscillating unit into a plurality; a plurality of amplifying units that respectively amplify the distributed outputs; and a combining unit that synthesizes the outputs of the amplifying units; There is a conventional technique in which a phase shifter is provided between the amplifying unit (see, for example, Patent Document 3). Then, the power ratio of the two outputs can be changed by the phase shifter control, and the phase between the two outputs can be in phase or in phase.
JP 59-165399 A Japanese Patent Publication No.62-48354 JP 56-132793 A

  However, in the configuration of the conventional multiple power feeding method, as described below, it is difficult to heat-treat objects to be heated in various shapes, types, and quantities stored in a heating chamber to a desired state. Had.

  It is possible to optimize the oscillation frequency according to the detection result of the impedance of the heating chamber and the reflected power, to control the heating unevenness, or to operate with better power efficiency, but with microwave power feeding from one place, It was not enough to cope with various shapes, types and amounts of heated objects. In addition, in order to achieve an output equivalent to a commercially available microwave oven, a plurality of final stage amplifying units using a semiconductor element with the maximum output of microwave power are required, and microwaves are transmitted from the plurality of amplifying units to the power feeding units, respectively. Is the cheapest and has stable performance.

  When the conventional configuration is applied to power supply at a plurality of locations, the detection error increases because the influence of transmitted power between the power supply units cannot be grasped only by impedance detection of the heating chamber. The control for tracking the frequency by operating power feeding at a plurality of locations at the same oscillation frequency is not enough to cope with heated objects having various shapes, types, and amounts, which is not much different from power feeding from one location.

  In addition, there is also a problem that it takes too much time to check the detection of impedance and reflected power of the heating chamber for all the combined conditions of the oscillation frequency control and phase difference control to the power supply units at multiple locations. .

The present invention solves the above-described conventional problems. For a heating chamber that accommodates an object to be heated, each of the power feeding units has reflected power that returns to the same power feeding unit, transmitted power that is transmitted to another power feeding unit, and reflection. Determine the relative phase difference of transmitted power with respect to power, determine the power supply unit to be used, oscillation frequency, and phase difference based on the grasped information, and start microwave heating, microwave power in a short time By obtaining information that affects the reflection and transmission performance of the light source and optimally controlling the oscillation frequency and phase difference, the object to be heated of various shapes, types, and quantities can be heated to the desired state, and at the same time, the heating chamber An object of the present invention is to provide a microwave generation processing apparatus that can suppress the microwave power returned from the power source to a low level and operates efficiently.

  In order to solve the above-described conventional problems, a microwave processing apparatus of the present invention includes a heating chamber that accommodates an object to be heated, an oscillation unit, a power distribution unit that distributes the output of the oscillation unit to a plurality, and the power A plurality of phase variable sections that vary the output phase of the distribution section; a plurality of amplification sections that respectively amplify the power of the output of the phase variable section; and a plurality of power supply sections that feed the output of the amplification section to the heating chamber. A plurality of power detection units that detect microwave power transmitted from the power supply unit in the direction of the amplification unit, and a control unit that controls an oscillation frequency of the oscillation unit and a phase difference of the phase variable unit, The control unit is configured such that, with respect to the heating chamber in which the object to be heated is accommodated, the reflected power returning to the same power feeding unit, the transmitted power transmitted to another power feeding unit, and the transmitted power relative to the reflected power for each of the power feeding units. After grasping the typical phase difference, The power supply unit to be used, the oscillation frequency, and the phase difference are determined, and the microwave heating is started to obtain information that affects the reflection and transmission performance of the microwave power in a short time. By optimally controlling the phase difference, it is possible to heat objects to be heated having various shapes, types, and amounts to a desired state, and at the same time, to suppress microwave power returning from the heating chamber to be low and to operate efficiently.

  The first invention includes a heating chamber that accommodates an object to be heated, an oscillation unit, a power distribution unit that distributes the output of the oscillation unit to a plurality of phases, a plurality of phase variable units that vary the output phase of the power distribution unit, It has a plurality of amplifying units each for amplifying the output of the phase variable unit, and a plurality of power feeding units for feeding the output of the amplifying unit to the heating chamber, and detects the microwave power transmitted from the power feeding unit in the direction of the amplifying unit. A plurality of power detection units, and a control unit for controlling the oscillation frequency of the oscillation unit and the phase difference of the phase variable unit, the control unit is the same for each of the power supply units with respect to the heating chamber containing the object to be heated. After grasping the reflected power returning to the power feeding unit, the transmitted power transmitted to another power feeding unit, and the relative phase difference between the transmitted power and the reflected power, the power feeding unit to be used, the oscillation frequency, and the phase difference are determined based on the grasped information. Confirmed and configured to start microwave heating, each The phase difference relative to the reflected power value and transmitted power value between the electrical parts can be clearly grasped, and the fluctuation characteristics of the total reflected power of each power feeding part for all oscillation frequency control and phase difference control can be calculated. The effect of controlling the electric power can be reliably extracted, and the object to be heated of various shapes, types and amounts can be heated to a desired state.

  In the second invention, the oscillation frequency of the oscillating unit is changed, power is fed from only one of the plurality of feeding units, the reflected power returning to the same feeding unit, and the transmitted power transmitted to another feeding unit are supplied to the power detection unit. It is configured to detect the reflection / transmission characteristics for all the power supply units, storing the reflected power and transmission power for the detected oscillation frequency fluctuation and the relationship between the power supply source and the power supply unit as the transmission destination. It is possible to clearly grasp the reflected power and transmitted power of each microwave of the power feeding unit, and to reliably extract the effect of controlling the oscillation frequency and phase difference of the microwave power to be fed. Various shapes and types -The to-be-heated object from which quantity differs can be heated to a desired state.

In the third invention, the oscillation frequency of the oscillating unit is changed, and power is fed simultaneously from only two of the plurality of feeding units, the reflected power returning to the feeding unit that is the feeding source, and the transmitted power transmitted from another feeding unit are The combined total reflected power is detected by the power detection unit, and the two-feed reflection characteristics are stored to store the total reflected power with respect to the detected oscillation frequency fluctuation and the relationship between the power supply source and the power supply unit as the transmission destination. Along with the grasping information of the second invention, the relative phase difference between the reflected power and the transmitted power that affects the mutual interference of the microwaves fed from a plurality of power feeding units can be clearly grasped, and the microwaves to be fed Thus, the effect of controlling the oscillation frequency and phase difference can be reliably extracted, and various objects to be heated of different shapes, types and amounts can be heated to a desired state.

  The fourth invention is configured to control the combination of the power feeding units having the largest average value of the transmitted power stored in the reflection / transmission characteristic detection as a group, and the transmitted power between the power feeding units is large. By controlling the oscillation frequency and phase difference for combinations that have a high mutual interference effect, the effect can be extracted more reliably, and various objects with different shapes, types, and quantities can be heated to the desired state. be able to.

  According to a fifth aspect of the present invention, a combination of power feeding units in which the average value of transmitted power stored in the detection of reflection / transmission characteristics exceeds a predetermined threshold is controlled as another group, and mutual interference is achieved. By controlling the oscillation frequency and phase difference for the combination with high effect, the effect can be extracted more reliably, and various objects of different shapes, types, and quantities can be heated to the desired state. it can.

  In the sixth aspect of the invention, the detection of the two-feed reflection characteristics is performed for the combination of the groups, and the detection of the two-feed reflection characteristics is omitted for the other combinations. By controlling the oscillation frequency and phase difference for high combinations, the effect is more reliably extracted, and the combination with less effective effects is excluded from the phase difference control target, and detection is also omitted, so heating conditions can be determined in a short time. Can be realized.

  According to a seventh aspect of the present invention, each of the power feeding units for controlling the oscillation frequency and the phase difference is determined based on the reflected power stored in the detection of the reflection / transmission characteristics and the total reflected power stored in the detection of the transmission power and the two-feed reflection characteristics. The total reflected power is grasped, the oscillation frequency and phase difference that minimize the total value of the total reflected power of each power supply unit are determined, and the total reflected power under the determined oscillation frequency and phase difference condition is a predetermined threshold value. The power supply unit exceeding the limit is designed to limit the output microwave power, and the fluctuation characteristics of the total reflected power of each power supply unit for all oscillation frequency control and phase difference control can be calculated from the grasped information. Thus, it is possible to determine the optimum microwave heating conditions in a short time, and it is possible to heat an object to be heated of various shapes, types, and amounts to a desired state. Moreover, it is possible to prevent the components such as the semiconductor element from being deteriorated by heat generation or being damaged by the microwave power returning from the power feeding unit toward the amplification unit.

  In the eighth aspect of the invention, the control unit continues the detection by the power detection unit even during the microwave heating, and when the detected microwave power fluctuates by a predetermined threshold or more from the value at the start of heating, the control unit reflects / transmits Detecting characteristics and two-feed reflection characteristics, replacing the stored reflected power, transmitted power, and total reflected power information, and determining the power feeding unit, oscillation frequency, and phase difference to be used based on the replaced information In this configuration, microwave heating is continued. By updating the stored information, it is possible to eliminate the influence of changes due to heating of the object to be heated, and to continue optimal control. Various shapes and types -Heating objects with different amounts can be heated to a desired state and operated efficiently at the same time. Moreover, since the detection information of the power detection unit during heating is used as a basis, the stored information can be updated at the optimum and minimum number of times, and the time required for heating can be minimized.

  According to a ninth aspect of the present invention, the threshold for the fluctuation of the microwave power detected by the power detection unit of the power feeding unit that limits the output microwave power is the power detection of the power feeding unit that does not limit the output microwave power. The threshold for determining the microwave output limit is set more finely than the threshold for other power supply efficiency monitoring, so that the threshold for the fluctuation of the microwave power detected at It is possible to achieve both of ensuring safety for preventing component deterioration and damage and shortening the heating time by supplying more microwave power.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a microwave processing apparatus according to the first embodiment of the present invention.

  In FIG. 1, the microwave generation unit includes oscillation units 1 a and 1 c configured using semiconductor elements, power distribution units 2 a and 2 c that distribute the output of the oscillation units 1 a and 1 c in two, and outputs of the power distribution units 2 a and 2 c, respectively. Amplifying units 4a to 4d configured using semiconductor elements to be amplified, power feeding units 5a to 5d for feeding the microwave output amplified by the amplifying units 4a to 4d into the heating chamber 8, and power distribution units 2a and 2c and amplification Phase variable units 3a to 3d that are inserted into a microwave transmission path that connects the units 4a to 4d and generates an arbitrary phase difference between input and output, and microwave transmission paths that connect the amplifiers 4a to 4d and the power feeding units 5a to 5d The power detectors 6a to 6d that detect the microwave power that is inserted and returned from the power feeding units 5a to 5d, and the oscillation units 1a and 1c that generate the oscillation power according to the total reflected power detected by the power detectors 6a to 6d. It is constituted by a control unit 7 for controlling the phase difference between the frequency and the phase variable parts 3 a to 3 d.

  About the microwave processing apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, the object to be heated 9 is stored in the heating chamber 8, and the heating setting is input from the operation unit (not shown), and heating is started. The control unit 7 that has received the heating start signal outputs a control output signal according to the heating condition after the heating condition is determined, and the microwave generation unit starts its operation. In the case of a heating condition that uses all the power supply units 5a to 5d, the control unit 7 operates a drive power supply (not shown) to supply power to the oscillation units 1a and 1c. At this time, the oscillation frequency of the oscillation units 1a and 1c is supplied with a voltage signal set to 2450 MHz, for example, and oscillation starts. When the oscillating units 1a and 1c are operated, their outputs are distributed approximately ½ each by the power distributing units 2a and 2c, and become four microwave powers. Thereafter, the drive power supply is controlled to operate the amplification units 4a to 4d.

  And each microwave electric power is electrically fed in the heating chamber 8 through the amplifier parts 4a-4d which operate | move in parallel, the electric power detection parts 6a-6d, and the electric power feeding parts 5a-5d. Of the microwave power fed into the heating chamber 8, the microwave power that has not been absorbed by the object 9 to be heated returns through the power feeding units 5a to 5d, and the total reflected power of each of the power feeding units 5a to 5d is the power. A signal detected by the detection units 6a to 6d and proportional to the total reflected power amount is sent to the control unit 7, and the total reflected power of each of the power feeding units 5a to 5d is grasped.

  Before moving to microwave heating, the control unit 7 grasps the fluctuation characteristics with respect to the oscillation frequency and the fluctuation characteristics with respect to the phase difference of the total reflected power of each of the power feeding units 5a to 5d, and the oscillation frequency at which the total reflected power becomes a minimum value and Select the phase difference and confirm the heating conditions.

  The fluctuation characteristics of the oscillation frequency include, for example, the total reflected power returned from the power supply units 5a to 5d while changing the oscillation frequency of the oscillation units 1a and 1c at a 1MHz pitch until reaching the oscillation frequency from 2400MHz to 2500MHz. It can be detected and obtained by 6a-6d. The variation characteristic of the phase difference can be obtained by detecting the variation characteristic of the oscillation frequency by changing the condition of the phase difference generated by the phase variable units 3a to 3d from 0 degrees to 360 degrees for every 10 degrees pitch, for example. In order to detect all data in this way, in the case of the above example, it is necessary to detect 36 oscillation frequency fluctuation characteristics. In order to obtain a more optimal heating result, more detection is required when the oscillation frequency control of the plurality of oscillation units 1a and 1c and the phase difference control of the phase variable units 3a to 3d are different.

  However, in the present invention, the fluctuation characteristics of the total reflected power with respect to all oscillation frequency control and phase difference control are calculated from the phase difference relative to the reflected power value and transmitted power value of each power feeding unit. For example, the total reflected power of the power supply unit 5a is the reflected power value fed from the power supply unit 5a and returned to the same power supply unit 5a, and the transmitted power values transmitted from the other power supply units 5b to 5d to the power supply unit 5a. , And vector addition using the relative phase difference between the reflected power and each transmitted power. Further, the total reflected power when the phase difference condition of any of the power feeding units 5a to 5d is different can be obtained by adding the phase variation to each relative phase difference and adding the vector.

  The oscillation frequency variation characteristic of the reflected power value from the power supply unit 5a to the power supply unit 5a and the transmitted power value from the power supply unit 5a to each of the power supply units 5b to 5d varies the oscillation frequency of the oscillation unit 1a, and only the amplification unit 4a. It can be grasped by detecting the reflection / transmission characteristics that are operated, fed from only one place of the feeding section 5a, and detected by the power detection sections 6a to 6d. Similarly, the reflected power value and the transmitted power value from the power feeding units 5b to 5d can be grasped by detecting the reflection / transmission characteristics. Further, power is fed simultaneously from only two places of the power feeding units 5a and 5b, and the reflected power from the power feeding unit 5a to the power feeding unit 5a and the power feeding from the power feeding unit 5b are detected by detecting the two power feeding reflection characteristics detected by the power detection unit 6a. The oscillation frequency variation characteristic of the total reflected power value obtained by adding the transmitted power to the unit 5a is obtained. 2 Reflected power and transmitted power can be calculated by back-calculating from the total reflected power value obtained by detecting the feeding reflection characteristic and the reflected power value and the transmitted power value grasped by detecting the reflection / transmission characteristic fed from only one of the feeding parts 5a and 5b. The relative phase difference of power can be grasped. Even if all combinations of detection of the reflection / transmission characteristics and detection of the two-feeding reflection characteristics are performed, there are 10 patterns, and the detection time can be shortened.

  Since the phase difference control is more effective as the mutual interference of the microwave power fed from the power feeding units 5a to 5d becomes stronger, the phase difference control is performed by grouping combinations with a large amount of transmitted power between the power feeding units 5a to 5d. The effect can be brought out more reliably. A combination having a large amount of transmitted power between the power feeding units 5a to 5d can be grasped from a result of detection of reflection / transmission characteristics. In addition, since the small transmitted power value has little influence on the total reflected power even if the vector addition is performed, the combination having a small transmitted power between the power feeding units 5a to 5d is excluded from the phase difference control target, and the detection of the two-feed reflection characteristics is also omitted. Detection time can be further reduced.

  From the information obtained in a shorter time as described above, it is possible to calculate the fluctuation characteristics of the total reflected power for all oscillation frequency control and phase difference control, determine the optimum heating condition from among them, and determine the microwave power to be fed Oscillation frequency and phase difference can be controlled, and heated object 9 having various shapes, types and amounts can be heated to a desired state, and at the same time, microwave power returning from heating chamber 8 can be reduced and operated efficiently. Can do.

  Even during the microwave heating, the detection by the power detection units 6a to 6d is monitored by the control unit 7, and when the detected microwave power fluctuates more than a predetermined threshold value from the value at the start of heating, the power supply units 5a to 5d. For the power feeding part involved in the change of the power, the reflection / transmission characteristics are detected and the two-feeding reflection characteristics are detected, and the stored reflected power, transmitted power and total reflected power information are exchanged. By determining the power supply unit, oscillation frequency, and phase difference to be used as a basis, and continuing microwave heating, the optimum control can be continued by eliminating the effects of changes due to heating of the object to be heated. Various shapes and types -Heating objects with different amounts can be heated to a desired state and operated efficiently at the same time. Moreover, since the detection information of the power detection unit during heating is used as a basis, the stored information can be updated at the optimum and minimum number of times, and the time required for heating can be minimized.

When there is a power supply unit that cannot set a heating condition in which the total of reflected power and transmitted power falls within a predetermined threshold, such as when heating an object to be heated 9 that absorbs extremely little microwave power, Limiting the microwave power output from the power supply unit to suppress self-heating of each component of the transmission path leading to the power supply to the heating chamber 8, and returning from the power supply units 5a to 5d to the amplification units 4a to 4d It is possible to prevent parts such as a semiconductor element from being deteriorated or damaged by heat generated by the above. While the output of the microwave power of the power supply unit is limited, the detection of the power detection units 6b to 6d is continued, and the detected microwave power fluctuates more than a predetermined threshold value from the value at the start of heating. Detecting reflection / transmission characteristics and detection of two-feeding reflection characteristics for power supply parts involved in changes in power supply parts 5a to 5d, and replacing stored reflected power, transmitted power, and total reflected power information Then, based on the replaced information, the power supply unit to be used, the oscillation frequency, and the phase difference are determined, and the microwave heating is continued. However, the threshold for the fluctuation of the microwave power detected by the power detection unit of the power supply unit that limits the output microwave power is to ensure the safety of component deterioration and damage prevention of semiconductor elements and more microwaves. In order to achieve both shortening of the heating time by power feeding, it is set more finely than the threshold of other power feeding efficiency monitoring.

  In the above description, an example in which four phase variable units 3a to 3d are inserted has been described. However, a configuration may be adopted in which the phase variable units 3a to 3d are inserted only into one output of each of the power distribution units 2a and 2c. Further, the oscillation units 1a and 1c can be configured to be four without using the power distribution units 2a and 2c.

  As described above, the microwave processing apparatus according to the present invention has a plurality of power supply units, and can provide a device that changes the oscillation frequency of the microwave power to be supplied and the phase difference between the power supply units. It can also be applied to uses such as a heating device using dielectric heating, a garbage disposal machine, or a microwave power source of a plasma power source which is a semiconductor manufacturing device.

Configuration diagram of microwave processing apparatus according to Embodiment 1 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1c Oscillation part 2a, 2c Power distribution part 3a-3d Phase variable part 4a-4d Amplification part 5a-5d Power supply part 6a-6d Power detection part 7 Control part 8 Heating chamber 9 Heated object

Claims (9)

A heating chamber that accommodates an object to be heated, an oscillation unit, a power distribution unit that distributes the output of the oscillation unit into a plurality of phases, a plurality of phase variable units that vary the output phase of the power distribution unit, and the phase variable unit A plurality of amplifying units for amplifying the output of each of the power supplies and a plurality of power feeding units for feeding the output of the amplifying unit to the heating chamber, and detecting microwave power transmitted from the power feeding unit toward the amplifying unit A plurality of power detection units, and a control unit for controlling the oscillation frequency of the oscillation unit and the phase difference of the phase variable unit,
The control unit has a reflected power returning to the same power feeding unit, a transmitted power transmitted to another power feeding unit, and a transmitted power with respect to the reflected power with respect to the heating chamber containing the object to be heated. After the relative phase difference is grasped, the microwave processing apparatus configured to start the microwave heating by determining the power supply unit to be used, the oscillation frequency, and the phase difference based on the grasped information. The oscillation frequency of the oscillating unit is varied, power is fed from only one of the plurality of feeding units provided, and reflected power returning to the same feeding unit and transmitted power transmitted to another feeding unit are transmitted by the power detection unit. Detected and reflected / transmitted power with respect to the detected oscillation frequency fluctuation, and the reflection / transmission characteristics that store the relationship between the power supply source and the power supply unit as a transmission destination are detected for all the power supply units. The microwave processing apparatus according to claim 1. Fluctuating the oscillation frequency of the oscillating unit, supplying power simultaneously from only two of the plurality of power supply units, the reflected power returning to the power supply unit of the power supply source and the transmitted power transmitted from another power supply unit are combined A configuration in which the total reflected power is detected by the power detection unit, and two-feed reflection characteristics are stored that store the total reflected power with respect to the detected oscillation frequency fluctuation and the relationship between the power supply source and the power supply unit as a transmission destination. Item 2. The microwave processing apparatus according to Item 1. 4. The microwave processing apparatus according to claim 1, wherein a combination of the power feeding units having the largest average value of transmitted power stored in the detection of the reflection / transmission characteristics is controlled as a group. 5. 5. The configuration according to claim 1, wherein a combination of the power feeding units in which an average value of transmitted power stored in the detection of the reflection / transmission characteristics exceeds a predetermined threshold is controlled as another group. The microwave processing apparatus as described in. 6. The configuration according to claim 1, wherein the two-feed reflection characteristics are detected for the group combinations, and the detection of the two-feed reflection characteristics is omitted for the other combinations. Microwave processing equipment. From the reflected power stored in the detection of the reflection / transmission characteristics and the total reflected power stored in the transmission power and the detection of the two-feeding reflection characteristics, the total reflected power of each of the power feeding units for controlling the oscillation frequency and the phase difference The oscillation frequency and the phase difference that minimize the total value of the total reflected power of each power feeding unit are determined, and the total reflected power under the determined oscillation frequency and phase difference condition exceeds a predetermined threshold value. The microwave processing apparatus according to any one of claims 1 to 3, wherein the power supply unit is configured to limit the output microwave power. The control unit continues the detection by the power detection unit even during microwave heating, and detects the reflection / transmission characteristics when the detected microwave power fluctuates more than a predetermined threshold value from the value at the start of heating. And detecting the two-feeding reflection characteristics, replacing the stored reflected power, transmitted power, and total reflected power information, and determining the feeding unit, oscillation frequency, and phase difference to be used based on the replaced information, The microwave processing apparatus according to any one of claims 1 to 3, wherein microwave heating is continued. The threshold for the fluctuation of the microwave power detected by the power detection unit of the power supply unit that limits the output microwave power is the power detection unit of the power supply unit that does not limit the output microwave power. The microwave processing device according to any one of claims 1 to 3 or claim 8, wherein the microwave processing device has a configuration different from a threshold value for fluctuations in detected microwave power.

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