JP3780893B2 - Microwave generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for generating a microwave by driving a magnetron, and more particularly to a method of driving a plurality of magnetrons simultaneously by a single high voltage power source.
[0002]
[Prior art]
Conventionally, as this type of microwave generator, there has been one described in FIGS . 6 and 7 , for example. FIG. 6 is for driving two magnetrons with a conventional microwave generator.
[0003]
The microwave generator shown in FIG. 6 requires a dedicated power source for each magnetron. If there are two magnetrons, two power sources are required. That is, two high-voltage transformers 7, high-voltage capacitors 8, and high-voltage diodes 9 constituting the power supply are also required. Since these parts handle large amounts of power at high voltage, the cost burden is large in terms of size and weight.
[0004]
FIG. 7 adopts an inverter power supply system as a power supply for driving the magnetron. That is, a commercial power source is switched by a rectifier circuit 14, a choke 13 and a smoothing capacitor 12 constituting a smoothing circuit, a resonance capacitor 11 for high-frequency oscillation, and a switching operation that controls resonance based on a signal 15 of an input current detection circuit. and element 10, an inverter power source control circuit 16 for driving the same. Conventionally, these require the same number as the number of magnetrons, and are expensive and large in volume.
[0005]
[Problems to be solved by the invention]
Therefore, a means for connecting and driving a plurality of magnetrons to one power source is required.
[0006]
However, when a plurality of magnetrons are connected in parallel with a single power source, there is a difference in the characteristics of each magnetron, so a difference occurs in the currents flowing between the magnetrons, making it impossible to achieve a balance. In particular, as a special characteristic of the operation characteristics of the magnetron, current does not flow up to a certain predetermined voltage, but when the voltage exceeds a certain predetermined voltage, current suddenly flows, and the current greatly changes with a slight voltage change. Because of this characteristic, the difference in current flowing through each magnetron is large, and the balance is greatly lost.
[0007]
An object of the present invention is to solve such a problem that the balance is lost due to characteristic variations of individual magnetrons, and an object of the present invention is to provide a microwave generator in which each magnetron operates stably while maintaining a certain balance. .
[0008]
[Means for Solving the Problems]
In order to solve the above-described conventional problems, the microwave generator of the present invention includes a plurality of magnetrons, a high-voltage power source that supplies high-voltage power to these magnetrons, and operation characteristic variable means that can change the operation characteristics of the magnetron. Detecting the anode current of each magnetron, and detecting one of the plurality of magnetrons as a standard magnetron and detecting the anode current signal of the standard magnetron detected by the anode current detecting means of the standard magnetron and the anode current of other magnetrons And an operating characteristic variable control means for comparing the anode current signal detected by the means and controlling the operating characteristic variable means of the magnetron based on the result.
[0009]
As a result, the balance between the anode currents flowing through the respective magnetrons is maintained, thereby enabling stable operation. As a result, a plurality of magnetrons can be driven by one power source.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, a plurality of magnetrons that generate microwaves, a high-voltage power source that supplies high-voltage power to these magnetrons, operating characteristic variable means that can change the operating characteristics of the magnetron, An anode current detection means for detecting the anode current of the magnetron and an operation characteristic variable control means for controlling the operation characteristic variable means of the magnetron, the operation characteristic variable control means being detected by the anode current detection means of each magnetron comparing the anode current signals to each other, by the anode current of the magnetron to control the operating characteristic varying means to be equal, the balance of the anode current caused by variations in the particularities and the individual operating characteristics of the operating characteristics of the magnetron It operates stably and in a well-balanced manner without causing collapse.
[0011]
According to a second aspect of the present invention, there is provided a standard magnetron having a fixed operating characteristic among a plurality of magnetrons that generate microwaves , a magnetron capable of changing operating characteristics other than the standard magnetron, and the standard magnetron a high voltage power supply for supplying high voltage power to those of the magnetron including a operating characteristic varying means for said operating characteristics make change the operating characteristics of the possible magnetron changed, an anode current detecting means for detecting the anode current of the individual magnetron wherein the operating characteristic variable control means compares an anode current signal of the standard magnetron detected by the pre-Symbol detection means, and an anode current signal detected by the anode current detection means other magnetron, the other Magnetron anode current is equal to the standard magnetron anode current By controlling the operating characteristic variable means so that, without causing imbalance of the anode current caused by variations in the particularities and the individual operating characteristics of the operating characteristics of the magnetron is operated stably balanced manner.
[0012]
In particular, the operation characteristic changing means of the microwave generator can be easily realized by changing the voltage of the operation characteristic of the magnetron. In addition, stable operation can be realized.
[0013]
According to the fourth aspect of the present invention, in particular, the means for changing the voltage of the operating characteristics of the magnetron in the microwave generator can be realized by changing the magnetic field strength of the magnetron.
[0014]
The invention according to claim 5 can be easily mounted on the magnetron, particularly by providing a magnetic field adjusting coil as means for changing the magnetic field strength of the magnetron in the microwave generator.
[0015]
According to the sixth aspect of the invention, in particular, fine control can be performed by providing an operation characteristic variable control means capable of varying the value of the current flowing through the magnetic field adjustment coil in the microwave generator.
[0016]
According to the seventh aspect of the present invention, in particular, the voltage of the operating characteristic of the magnetron can be increased or decreased or controlled in both directions by making the polarity of the current of the operating characteristic variable control means in the microwave generator reversible.
[0017]
The invention according to claim 8 is an inverter power source comprising a resonance capacitor and a switching element, in particular, the high voltage power source in the microwave generator, and can control the supplied power. Current can operate in a well-balanced manner.
[0018]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0019]
(Example 1)
FIG. 1 shows a circuit configuration diagram of a microwave generator according to Embodiment 1 of the present invention.
[0020]
In FIG. 1, reference numeral 7 denotes a high voltage transformer that boosts the voltage of a commercial power supply in order to supply high voltage power to the magnetron. The output voltage is composed of a high voltage capacitor 8 and a high voltage diode 9 to form a voltage doubler rectifier circuit. Power is being supplied. Two magnetrons, a standard magnetron 1 and a variable operating characteristic magnetron 2, are connected in parallel. Reference numeral 5 denotes an anode current detection means for the variable operating characteristic magnetron 2, and reference numeral 6 denotes an anode current detection means for the standard magnetron 1. 4 is an anode current signal difference detection amplification circuit that compares the signals of the two anode current detection means 5 and 6 and outputs the difference as a voltage, and 3 operates in accordance with the output voltage of the anode current signal difference detection amplification circuit 4. Coil current control means for controlling the current of the magnetic field adjustment coil 2-1 of the variable characteristic magnetron 2. The anode current signal difference detection amplification circuit 4 and the coil current control means 3 constitute an operation characteristic variable control means.
[0021]
FIG. 3 shows the structure of the variable operating characteristic magnetron 2. A plurality of vanes 2-2 are radially attached to the annular anode block 2-3 to form an oscillation space. 2-4 is a magnetic pole and 2-5 is a magnet, which applies a magnetic field to the oscillation space. Reference numeral 2-6 denotes an antenna that radiates microwave energy generated in the oscillation space. The cathode 2-8 is a direct heating type and is composed of a heater, and a cathode heating current is supplied from the cathode terminal 2-7. Reference numeral 2-1 denotes a magnetic field adjusting coil that adjusts the magnetic field strength applied to the oscillation space by being combined with the magnet 2-5, and adjusts the strength of the magnetic field by the current. Further, the change in the strength of the magnetic field is a change in the voltage of the operation characteristic of the variable operation characteristic magnetron 2. That is, if the magnetic field is strong, the operating voltage is high, and if the magnetic field is weak, the operating voltage is low.
[0022]
About the microwave generator comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.
[0023]
First, FIG. 5A shows the operating characteristics of the magnetron. The vertical axis represents voltage and the horizontal axis represents current. Voltage out is flow suddenly current exceeds the oscillation start voltage Vs, the current changes significantly with respect to changes in voltage. The operating voltage is high when the magnetic field applied to the oscillation space is strong, and low when the magnetic field is weak. In general, magnetrons vary in operating voltage due to variations in the magnetic field strength of the magnets.
[0024]
Therefore, when two magnetrons are operated as in the microwave generator according to the embodiment of the present invention, there is a difference in operating characteristics between the individual magnetrons. FIG. 5B shows a case where the operating characteristic M2 of the variable operating characteristic magnetron 2 is lower than the operating characteristic M1 of the standard magnetron 1, and the anode current Ia1 of the standard magnetron 1 is small with respect to the operating voltage Vo. The anode current Ia2 of the variable magnetron 2 is increased, and a large difference is generated between the two so that the balance is lost. FIG. 5 ( d ) shows the case where the operational characteristics of the magnetrons are reversed and the magnitudes of Ia1 and Ia2 are reversed and the balance is greatly lost.
[0025]
Therefore, as shown in FIG. 5 ( c ), the anode current Ia1 of the standard magnetron 1 and the anode current Ia2 of the variable operating characteristic magnetron 2 are compared. If Ia2> Ia1, the magnetic field is strengthened by the magnetic field adjusting coil 2-1, and the operating voltage is increased. So that it matches the operating characteristics of the standard magnetron 1. By doing so, Ia1 and Ia2 are equal, and a balanced and stable operation is achieved. Conversely, if Ia2 <Ia1, the magnetic field adjusting coil 2-1 weakens the magnetic field and lowers the operating voltage, so that Ia2 = Ia1 and a balanced and stable operation can be achieved.
[0026]
FIG. 4 shows a mechanism of a control system for realizing the present invention. Reference numeral 6 in FIG. 4 denotes an anode current detection means of the standard magnetron 1 and shows its circuit configuration means. Reference numeral 5 denotes an anode current detecting means of the variable operating characteristic magnetron 2 and shows its circuit configuration. Both anode current detection means output signals by voltage means. Reference numeral 4 denotes an anode current signal difference detection amplification circuit that compares the signals of the anode current detection means of the respective magnetrons and outputs an output signal corresponding to the difference. Reference numeral 3 denotes coil current control means for controlling the magnitude and polarity of the current value that flows through the magnetic field adjustment coil 2-1 in response to the signal from the anode current signal difference detection amplification circuit 4. With the above configuration, the difference between the anode currents Ia1 and Ia2 of each magnetron is detected, and the current of the magnetic field adjustment coil 2-1 is controlled so that the difference is eliminated. As a result, the two magnetrons can operate stably while maintaining a balance. The anode current signal difference detection amplification circuit 4 and the coil current control means 3 constitute an operation characteristic variable control means.
[0027]
(Example 2)
FIG. 2 shows a circuit configuration diagram of the microwave generator according to the second embodiment of the present invention.
[0028]
In FIG. 2, reference numeral 7 denotes a high voltage transformer for supplying high voltage power to the magnetron. The high voltage capacitor 8 and the high voltage diode 9 constitute an output voltage rectifier circuit, and the high voltage power is supplied to the magnetron. A diode bridge 14 that rectifies the commercial power supply, a choke 13 that smoothes the rectified power, and a smoothing capacitor 12 are provided. A resonance circuit is formed by the resonance capacitor 11 and the high-voltage transformer 7, and the switching element 10 is turned on and off. An inverter power supply for converting to high frequency power is configured. Based on the signal from the input current detection circuit 15, the inverter power supply control circuit 16 controls ON / OFF of the switching element 10. As a result, the magnitude of the input current can be freely controlled.
[0029]
In the case of this configuration, the microwave generator of the present invention balances the anode current of each magnetron regardless of the magnitude of the input current, and enables stable operation. That is, the anode current of each magnetron also changes depending on the magnitude of the input current. The signals of the anode currents Ia1 and Ia2 of each magnetron also change, but the current values of the magnetic field adjustment coils 2-1 are controlled so that the difference is eliminated by the anode current signal difference detection amplification circuit 4, so that Ia1 and Ia2 Will be balanced and stable.
[0030]
【The invention's effect】
As described above, according to the first to eighth aspects of the invention, it is possible to maintain a balance between a plurality of magnetrons supplied with power from one high-voltage power supply and perform stable operation driving.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of a microwave generator according to a first embodiment of the present invention. FIG. 2 is a circuit configuration diagram of a microwave generator according to a second embodiment of the present invention. FIG. 4 is a cross-sectional structural diagram of a magnetron with variable operating characteristics in the microwave generator of Example 2. FIG. 4 is a diagram showing a mechanism of a control system for realizing the microwave generator of the present invention. Operation characteristic diagram showing operation of the magnetron of the apparatus [FIG. 6] Circuit configuration diagram of a conventional microwave generator [FIG. 7] Circuit configuration diagram of a conventional microwave generator [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Standard magnetron 2 Operation characteristic variable type magnetron 2-1 Magnetic field adjustment coil 3 Coil current control means 4 Anode current difference detection amplification circuit 5 Operation characteristic variable type magnetron anode current detection means 6 Standard magnetron anode current detection means

Claims (8)

A plurality of magnetrons that generate microwaves, a high-voltage power supply that supplies high-voltage power to these magnetrons, operating characteristic variable means that can change the operating characteristics of the magnetron, and an anode current that detects the anode current of each magnetron detection means, and a operating characteristic variable control means for controlling an operating characteristic varying means of the magnetron, the operating characteristic variable control means compares the anode current signals respectively detected by the anode current detection means of each magnetron, each A microwave generator characterized by controlling the operating characteristic varying means so that the anode currents of magnetrons are equal . Among a plurality of magnetrons that generate microwaves , one standard magnetron whose operating characteristics are fixed, a magnetron whose operating characteristics other than the standard magnetron can be changed, and high voltage power to these magnetrons including the standard magnetron comprising a high voltage power supply for supplying a operating characteristic varying means for said operating characteristics make change the operating characteristics of possible changes magnetron, an anode current detecting means for detecting the anode current of the individual magnetron, the operating characteristic variable control means compares the anode current signal of the standard magnetron detected by the pre-Symbol detection means, and an anode current signal detected by the anode current detection means other magnetron, the other magnetron anode current the standard magnetron the operating characteristics accepted to be equal to the anode current of Microwave generating apparatus and controls the means.   3. The microwave generator according to claim 1, wherein the operating characteristic changing means changes the voltage of the operating characteristic of the magnetron.   4. The microwave generator according to claim 3, wherein the operating characteristic varying means changes the voltage of the operating characteristic by changing the magnetic field strength of the magnetron.   The microwave generator according to claim 4, wherein a magnetic field adjusting coil is provided in the magnetron as means for changing the magnetic field intensity.   6. The microwave generator according to claim 5, wherein the current value of the magnetic field adjusting coil is changed by the operating characteristic variable control means. The microwave generator according to claim 5 or 6, wherein the polarity of the current of the magnetic field adjusting coil can be reversed. The microwave generator according to claim 1 or 2, wherein the high voltage power source is composed of an inverter power source including a resonance capacitor and a switching element, and has a function of controlling supply power.

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