JPH08236267A - High-frequency heating device - Google Patents

Abstract

PURPOSE: To extend the cycle of replacement repair of a magnetron by reducing influence upon the voltage of a power supply line and at the same time controlling operation so that respective magnetrons have a nearly same life in a high- frequency heating device provided with a plurality of magnetrons. CONSTITUTION: When the operation of two magnetrons is controlled, an upper magnetron is intermittently operated and a lower magnetron is continuously operated in an A mode and vice versa in a B mode. Operation time is integrated during heating operation, and the A mode operation and the B node operation are alternately performed every time when a predetermined time elapses.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency heating apparatus having a plurality of magnetrons.

[0002]

2. Description of the Related Art In a commercial high-frequency heating apparatus, two or more magnetrons are often used to heat an object to be cooked in the shortest possible time. Generally, when controlling the heating output with a high-frequency heating device, the so-called intermittent operation is performed in which the magnetron oscillates and pauses alternately, and the output control is realized by changing the distribution of the oscillations and pauses within a certain period. There is. In a high-frequency heating device equipped with two or more magnetrons, heating output is controlled by intermittently operating each magnetron within the same period and changing the distribution of oscillation and pause time of the intermittent operation.

FIG. 5 is a timing chart showing an example of operation control of a magnetron in a high-frequency heating apparatus having two magnetrons. This figure shows 70 for rated output.
It shows the operating state of each magnetron when performing output control of%. During the period T of one cycle, the upper magnetron and the lower magnetron are controlled so that 70% of the time is oscillated and 30% of the time is in the oscillation stop state, thereby achieving 70% output control as a whole. To be done. When 60% output control is performed with respect to the rated output, the time of one cycle T does not change, and the time distribution of oscillation and oscillation stop is changed to 60% and 40% during the period T, respectively. .

[0004]

However, in the high-frequency heating device, the power supply current suddenly flows at the start of oscillation of the magnetron. In the example of FIG. 5, the magnetron starts oscillating twice in the period of one cycle T. When a sudden power supply current flows through the magnetron, a voltage drop occurs in the power supply line, which affects other electric devices connected to the power supply line. In order to reduce this phenomenon, it is preferable to reduce the number of oscillations of the magnetron as much as possible.

The present invention has been made to solve the above problems, and a first object thereof is to reduce the number of times the magnetron starts oscillating in a high frequency heating apparatus having a plurality of magnetrons. An object of the present invention is to provide a high-frequency heating device that reduces the influence on the voltage of the.

A second object of the present invention is to control the operation of each magnetron so that the cumulative operating time of a plurality of magnetrons is approximately equalized in a high frequency heating apparatus in which the influence on the voltage of the power supply line is reduced. An object of the present invention is to provide a highly reliable high-frequency heating device capable of avoiding the failure of a specific magnetron early and extending the time until replacement and repair of the magnetron.

[0007]

In order to achieve the above object, the first high-frequency heating apparatus according to the present invention is a magnetron that continuously oscillates from the plurality of magnetrons, that is, performs continuous operation. At least one is determined, and for the other magnetrons, oscillating and oscillating are alternately performed, that is, first deciding means for deciding to perform intermittent operation, and oscillation and oscillation stop in the intermittent operation. The second determining means for determining the time distribution according to the adjustment amount of the heating output, and the magnetron determined to perform the continuous operation by the first determining means are continuously operated, and the intermittent operation is performed. A generator for controlling the oscillation of the plurality of magnetrons so that the determined magnetrons are intermittently operated with the time distribution determined by the second determining means. It comprises a control means.

The second high-frequency heating apparatus according to the present invention further comprises integrating means for integrating the operating time during heating operation, and determining means for determining whether the integrated time by the integrating means has reached a predetermined time. And the first determining means comprises:
When it is determined by the determining means that the integrated time has reached a predetermined time, a changing means for changing the magnetron for continuous operation to another magnetron is included.

In the high frequency heating apparatus according to the present invention,
It is preferable that the change by the changing means is performed during a period when the heating operation is not performed.

[0010]

In the first high-frequency heating apparatus according to the present invention, when the heating operation is performed, the first determining means is such that at least one magnetron of the plurality of magnetrons continuously oscillates and another magnetron is oscillated. The operating state of each magnetron is determined so that the oscillation and the oscillation stop are performed alternately, and an instruction is given to the oscillation control means. Therefore, any one of the magnetrons is always in the continuous operation state during the heating operation. Therefore, for example, in a high-frequency heating device equipped with two magnetrons, one magnetron is continuously operated and the other magnetron is intermittently operated during heating operation. When the heating output is narrowed down, the second determining means determines the time distribution so as to increase the rate of oscillation suspension in the intermittent operation according to the adjustment amount of the heating output, and the oscillation control means is based on this distribution. And cause the corresponding magnetron to oscillate and oscillate.

In the second high frequency heating apparatus according to the present invention,
With the start of the heating operation, the integrating means starts integrating the operating time. When the determining means determines that the integrated time has reached the predetermined time, the operation mode change request as the determination result is issued. Upon receiving the operation mode change request, the changing means included in the first determining means sets the magnetron, which has been in the continuous operation state until then, to the intermittent operation, and continuously operates at least one of the magnetrons which has been in the intermittent operation status until then. Change the operation mode as follows. Therefore, for example, in the high-frequency heating device including the first and second magnetrons, the operation mode is the first operation mode in which the first magnetron is in continuous operation and the second magnetron is in intermittent operation. When the change request is received, the operation mode is changed to the second operation mode in which the second magnetron is continuously operated and the first magnetron is in the intermittent operation state, and the operation mode change request is issued in the second operation mode. When received, the operation mode is changed to the first operation mode.

In the high-frequency heating device in which the change by the changing means is performed during the period when the heating operation is not performed, even if the operation mode change request is issued during the heating operation, the high-frequency heating apparatus waits for the end of the heating operation. The operation mode is changed from. That is, the operation mode is changed when all the magnetrons are stopped.

[0013]

As described above, in the first high frequency heating apparatus according to the present invention, at least one magnetron among the plurality of magnetrons is continuously operated, and the other magnetrons are intermittently operated. Therefore, the number of times the magnetron starts to oscillate can be reduced, so that the influence on the voltage of the power supply line during the heating operation can be reduced.

In the second high-frequency heating device according to the present invention,
The operation mode is changed every time a predetermined operation time has elapsed, and the magnetrons that are continuously operated are sequentially replaced. Therefore, the heating operation is performed while the oscillation time of each magnetron is kept substantially even, and it is possible to prevent the specific magnetron from quickly failing. As a result, it is possible for the user to prolong the time until the replacement and repair of the high-frequency generator, and it is possible for the service personnel of this device to save the trouble of frequent replacement and repair.

Further, since the operation mode is changed when the cooking is not performed, it is possible to avoid the change of the operation mode from affecting the voltage of the power supply line.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a high-frequency heating apparatus including two magnetrons, which is an embodiment of the present invention, FIG. 2 is a diagram showing an internal structure of a magnetron control unit in FIG. 1, and FIG. 3 is an operation mode of this embodiment. 4 is a control flowchart for explaining the changing method of FIG. 4, and FIG. 4 is a timing chart showing the operation modes of the two magnetrons in this embodiment.

In FIG. 1, a heating chamber 14 for heating an object 12 to be heated such as food is formed inside a main body housing 10 of the high frequency heating apparatus. In the heating chamber 14,
A turntable 16 on which the heating target 12 is placed is rotatably provided. An openable door (not shown) is provided at the front opening of the heating chamber 14, and the heating target 12 is put into and taken out of the heating chamber 14 via this door. The magnetrons 18a and 18b are arranged in two places in the upper and lower parts in the main body housing 10. The magnetron 1 is located above and below the heating chamber 14.
The high frequency generated in 8a and 18b, respectively, is applied to the heating chamber 1.
Waveguides 20a and 20b for guiding to 4 are provided. The high frequency waves guided by the waveguides 20a and 20b are radiated into the heating chamber 14 from the high frequency radiation ports 26a and 26b formed on the top wall 22 and the bottom wall 24 of the heating chamber 14, respectively, so that the object to be heated is heated. 12 is induction heated.

Rotating antennas 30a and 30b, which are rotatably driven by two motors 28a and 28b provided above and below the waveguides 20a and 20b, are attached to the tips of rotating shafts 32a and 32b, respectively, and the upper high-frequency radiation is generated. It is provided just below the mouth 26a and just above the lower high-frequency radiation mouth 26b. A control signal from the magnetron control unit 34 including a microcomputer or the like is supplied to the magnetrons 18a and 18b through the control lines 36a and 36b. This control signal controls the oscillation and oscillation stop of each magnetron. The magnetron control unit 34 independently controls the oscillation operations of the two magnetrons 18a and 18b.

The heating operation after the object 12 to be heated is placed on the turntable 16 will be described with reference to FIG.
When the operator operates the heating start switch (not shown),
The magnetron control unit 34 starts the heating operation according to the heating sequence stored in the internal memory in advance. That is, a control signal is supplied to the two magnetrons 18a and 18b through control lines 36a and 36b,
The oscillations of the magnetrons 18a and 18b are started.
The high frequency waves generated by the magnetrons 18a and 18b are sent to the heating chamber 14 through the waveguides 20a and 20b, respectively. The rotating antennas 30a and 30b are
By stirring the high frequency waves radiated from the high frequency radiation ports 26a and 26b, the heating target 12 is heated uniformly. During the heating operation, one of the two magnetrons is controlled to continuously oscillate, and the other is controlled to alternately oscillate and oscillate. At this time, the heating output is controlled by changing the ratio of the oscillation period and the oscillation suspension period of the magnetron which is operated intermittently.

The operation control method of the two magnetrons will be described below with reference to FIGS. 2 to 4. First, in FIG. 2 showing the internal configuration of the magnetron control unit 34, the adjustment amount of the heating output determined by the heating sequence is input to the intermittent operation distribution determining unit 341 that determines the ratio of oscillation and oscillation stop of intermittent operation. . The distribution determined by the intermittent operation distribution determining unit is the oscillation control units 345a and 345a.
45b is input. Further, the timer 343 is for measuring the time from the start of cooking to the end of cooking, and the result is input to the operating time determination unit 344. The operating time determination unit 344 integrates the cooking time, that is, the operating time, determines whether or not the integrated value has reached a predetermined time, and when it reaches, gives an operating mode change request to the operating state instruction unit 342. . The operating state instructing unit 342 determines whether the magnetrons 18a and 18b operate continuously or intermittently, and gives the instruction to the oscillation control units 345a and 345b provided for each magnetron. The oscillation control units 345a and 345b are means for controlling the oscillations of the two magnetrons 18a and 18b, respectively,
When the intermittent operation is instructed from the operation state instructing unit 342, the oscillation and the oscillation stop of the magnetron are controlled by the distribution determined by the intermittent operation distribution determining unit 341.

Hereinafter, referring to FIG. 2 and FIG. 4, FIG.
The operation control method will be described in detail with reference to the flowchart of FIG. 3 and 4, the operation mode A is a mode in which the upper magnetron 18a is intermittently operated and the lower magnetron 18b is continuously operated. Contrary to the B mode, the upper magnetron 18a is continuously operated and the lower magnetron 18a is operated. 18b is an operation mode in which intermittent operation is performed.

When the high-frequency heating apparatus of this embodiment is used for the first time, the FLAG in the operation time determination unit 344 is reset to 0 in step S10, and the operation mode in the operation state instruction unit 342 is changed to the A mode in step S11. Is set to. Here, FLAG is a flag for determining whether the operation time has reached a predetermined time and changing the operation mode. Next, cooking conditions such as the type of cooking are set in step S12, and when the start of cooking is instructed in step S13, the process proceeds to step S14, and heating cooking is performed according to the heating sequence corresponding to the cooking conditions. The operating time determination unit 344 integrates the operating time in step S15, determines the integrated value of the operating time in step S16, and when the operating time exceeds 10 hours, the operating time is determined in step S1.
FLAG is set to 1 at 7. In step S18, it is determined whether or not the heating and cooking is completed, and if the heating and cooking is to be continued, the process returns to step S14. Therefore,
During heating and cooking, the processing from step S14 to step S17 is repeated.

After completion of cooking, steps are from S18 to S19.
Then, the operation time determination unit 344 checks FLAG. When FLAG is set to 1, a driving mode change request is issued and a driving state instructing unit 342 is issued.
Is input to. In response to the operation mode change request, the operation state instruction unit 342 checks the current operation mode in step S20. When the operation mode is the A mode in step S20, the process proceeds to step S21 and B
When the operation mode is the B mode, the process proceeds to step S22 and is changed to the A mode. In either case, in the subsequent step S23, the operating time determination unit 34
The integrated value of operating time in 4 is cleared, and step S
FLAG is also reset to 0 at 24. After that, the process returns to step S12, and the next heating operation is performed under the newly set cooking condition.

If the operation time does not exceed 10 hours in step S16, FLAG is set in step S16.
Since it does not pass through 17, the step returns from S19 to S12 after the completion of cooking, and the heating operation is performed in the operation mode up to that point.

During heating and cooking, the operation state instructing section 342 determines the oscillation control section 345a when the operation mode is the A mode.
To the intermittent operation, and to the oscillation control unit 345b to instruct the continuous operation. When the operation mode is the B mode, the opposite operation is instructed.

According to the control flowchart of FIG. 3, the operation in the A mode and the operation in the B mode are alternately performed every 10 hours. Moreover, the change of the operation mode is not performed during the cooking operation, that is, in the state where the magnetron is oscillating. Therefore, changing the operation mode does not affect the voltage of the power supply line.

FIG. 4 shows an example of controlling the heating output to 70%, and FIG. 4 (a) shows the operating state in the A mode.
FIG. 4B shows an operating state in the B mode. In the A mode, the upper magnetron 18a is operated intermittently and the lower magnetron 18b is operated continuously. As described above, since the operation in the A mode and the operation in the B mode are alternately performed, each magnetron alternates between the continuous operation state and the intermittent operation state every 10 hours of operation time. At this time, one cycle T of the intermittent operation of the magnetron is preferably several tens of seconds, for example, about 20 to 30 seconds. This is because if the period T is too short, the magnetron will frequently repeat oscillation and stop, which defeats the purpose of reducing the number of times the magnetron starts oscillation. On the other hand, if the cycle T is too long, the output control cannot be performed well when the cooking time is short.

During one cycle T of FIG. 4A, the upper magnetron 18a oscillates for a period of 40% within one cycle T of 60%.
Pause for a period of%. During this time, the lower magnetron 18b is 1
Since it oscillates% during the period of 00, it means that the heating output of 70% is obtained as a whole. As described above, the control of the heating output is performed by changing the ratio of the oscillation and the oscillation stop within the predetermined one cycle T when the intermittent operation is performed.

In the above embodiments, the case where the number of magnetrons is two has been described, but the present invention can be applied to a high frequency heating apparatus having three or more magnetrons. In this case, one magnetron may be continuously operated and another magnetron may be intermittently operated, or one magnetron may be intermittently operated and another magnetron may be continuously operated. Further, by continuously operating one or more magnetrons and sequentially replacing the magnetrons that are continuously operated each time a predetermined operating time elapses, it is possible to avoid a long oscillation time of only a specific magnetron. At this time, if the number of continuously operating magnetrons is increased,
Although it helps reduce the number of times the magnetron starts oscillating,
Since the number of intermittently operating magnetrons is reduced, the controllable range of heating output is narrowed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a high frequency heating device of the present invention.

FIG. 2 is a configuration diagram showing an internal configuration of a magnetron control unit in FIG.

FIG. 3 is a control flow chart for explaining a method of changing the operation mode of the magnetron of the embodiment of the high-frequency heating device of the present invention.

FIG. 4 is a timing chart showing operation modes of the magnetron of the embodiment of the high-frequency heating device of the present invention.

FIG. 5 is a timing chart showing an operating state of a magnetron of a conventional high frequency heating device.

[Explanation of symbols]

 341 ... Intermittent operation distribution determining unit (second determining unit) 342 ... Operating state instructing unit (first determining unit) 344 ... Operating time determining unit (integrating unit and determining unit) 345a, 345b ... Oscillation control unit (oscillation control) means)

Claims (3)

[Claims] 1. In a high-frequency heating apparatus comprising a plurality of magnetrons, at least one magnetron to be continuously oscillated, that is, to perform continuous operation is determined from among the plurality of magnetrons, and the other magnetrons are determined. Firstly, the first determining means for determining that the oscillation and the oscillation stop are alternately performed, that is, the intermittent operation is performed, and the time distribution of the oscillation and the oscillation stop in the intermittent operation is determined according to the adjustment amount of the heating output. And a second determining means for continuously operating the magnetron determined to perform continuous operation by the first determining means, and determining the magnetron determined to perform intermittent operation by the second determining means. Oscillation control means for controlling the oscillations of the plurality of magnetrons so as to intermittently operate with a given time distribution. A high-frequency heating device characterized in that 2. An integration unit for integrating the operating time during heating operation, and a determination unit for determining whether or not the integration time by the integration unit has reached a predetermined time, and the first determination unit is the determination unit. The high-frequency heating apparatus according to claim 1, further comprising a changing unit that changes the magnetron for continuous operation to another magnetron when the integrated unit determines that the integrated time has reached a predetermined time. 3. The change by the changing means is performed during a period in which the heating operation is not performed.
The high frequency heating device according to.