JP2006253826A - Microwave generator, microwave power transmission device, and space photovoltaic power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave generator, a microwave power transmission device, and a space photovoltaic power generation system for improving phase synchronization accuracy and responsiveness. <P>SOLUTION: A reference signal having a frequency close to an intrinsic oscillation frequency of a magnetron 1 is injected to the magnetron 1 by an injection-locked circuit 20. By this, an output frequency of the magnetron 1 is drawn in the frequency of the reference signal. While, part of the output of the magnetron 1 and part of the reference signal are input to a feedback control circuit 21. A phase error between the magnetron 1 and the reference signal is calculated by the feedback control circuit 21. A control amount corresponding to the phase error is fed back to the injection-locked circuit 20. The reference signal, whose phase is adjusted corresponding to the control amount, is injected to the magnetron 1 by the injection-locked circuit. In this way, feedback control is executed. Consequently, it is possible to converge the frequency and the phase of the output of the magnetron 1 to a desired value respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, a microwave generator used in a space solar power generation system in which a huge solar cell panel is spread in outer space and generated electric power is transmitted to the ground with microwaves.

In the past, the Japan Aerospace Exploration Agency (JAXA) installed large solar panels in outer space in order to effectively use solar energy in preparation for the future depletion of fossil fuels. SSPS converted into microwaves or laser light and sent to the ground
(Space Solar Power System) concept announced.
In this SSPS, for example, when using microwaves, a space energy utilization system having a solar cell panel 100 having a size of about 5 km × 10 km as shown in FIG. 11 on a geostationary orbit 36,000 km above the equator. The power generated by the solar light 101 is converted into the microwave 103 by the oscillation module (size of about 1 m × 0.5 m × 0.3 m) 102 in the panel, and is received on the ground by the power transmission antenna 104 It is sent to the antenna 105 and used as energy such as electric power. In the future, it is aiming for 1 million KW class power generation.

  For the oscillation module used in the SSPS, the use of a magnetron having the advantages of high efficiency and high output is being studied. However, since the frequency stability of the magnetron is poor, it is difficult to stabilize the output phase of the microwave oscillation module using the magnetron. For example, for an antenna device that requires high-precision phase control like an active phase array. Had the disadvantage that it could not be used.

  Therefore, for example, as shown in FIG. 12, in recent years, a technique for stabilizing the oscillation frequency of the magnetron by incorporating feedback control of the anode current of the magnetron in the injection locking method has been proposed (for example, Japanese Patent Laid-Open No. Hei. 2002-43848 publication).

  In the conventional microwave generator shown in FIG. 12, a current (hereinafter referred to as “anode current”) is passed between an anode (anode) and a cathode (cathode) of a magnetron 201 by a DC power source 200 to be in an oscillation state. In this state, the reference signal generated by the reference signal generator 202 is injected into the magnetron 201 via the circulator 203, and the oscillation frequency of the magnetron 201 is synchronized with the reference signal. The microwave radiated from the magnetron 201 is extracted by the circulator 203, partially branched by the directional coupler 204, and input to the mixer 205.

The mixer 205 performs comparison with the reference signal, and the comparison result is input to the PC 207 via the LPF (low-pass filter) 206. The PC 207 obtains a frequency error and a phase error between the microwave output and the reference signal, and a control amount for eliminating the error is fed back to the DC power source 200. As a result, the amount of current input from the DC power source 200 to the magnetron 201 is adjusted, and the output of the magnetron 201 is converged to a predetermined frequency and phase.
Japanese Patent Laid-Open No. 2002-43848 (FIG. 1)

By the way, according to the conventional microwave generator described above, in order to converge the output phase of the magnetron 201 to the reference signal phase, for example, the output target value of the mixer 205 needs to be determined and stored in the PC 207 at the time of initial calibration. There is.
At this time, the output V _{IF of the} mixer 205 is given by the following equation (1), for example.

In the above equation (1), the first term is a basic DC component mixed in the mixer 205, and depends on the amplitude A _{1 of the} reference signal, the output amplitude A _{2 of the} magnetron, and the phase difference (θ ₁ −θ ₂ ). Change. The second term is a component obtained by adding offset components that change depending on the input levels of both signals, and this offset component needs to be obtained when determining the target value. The third term is a noise component of the mixer output, and is a component removed by the LPF 206 provided at the subsequent stage of the mixer 205.

  For example, in the microwave generator shown in FIG. 12, when determining the output target value of the mixer, for example, in an open loop state in which the PC 207 and the DC power source 200 are disconnected, the DC power source 200 The anode current applied to the magnetron 201 is gradually changed, the output of the LPF 206 at this time is measured by the PC 207, and the output target value of the mixer is set from the measurement result.

However, in general, the magnetron 201 has a property that when the anode current is changed, the output phase and the output amplitude thereof are changed, so that the output target value of the mixer is set while changing the anode current. In this method, the amplitude A _{2 of the} magnetron included in the first term and the second term in the above equation (1) changes, and the offset component indicated in the second term cannot be obtained with high accuracy. There was a problem. For this reason, in the conventional microwave generator, it is difficult to set an accurate output target value, and as a result, there is a problem that the phase synchronization accuracy and the like are reduced.

  Further, as described above, since the conventional microwave generator controls the magnetron 201 by changing the anode current, there is a possibility that not only the output phase but also the synchronization accuracy of the output amplitude is lowered. Thus, for example, when used in an active phased array, there is a problem that the radiation pattern is deteriorated due to fluctuations in the excitation amplitude distribution.

  Furthermore, the conventional microwave generator described above has a problem that the response is poor because the DC power supply 200 having a slow response is included in the feedback loop. For example, the conventional microwave generator shown in FIG. 12 has the disadvantage that it takes about 4 seconds to synchronize again after the phase of the reference signal changes and the phase is out of synchronization. It was happening.

  The present invention has been made to solve the above problems, and provides a microwave generator, a microwave power transmission device, and a space solar power generation system capable of improving phase synchronization accuracy and responsiveness. Objective.

In order to solve the above problems, the present invention employs the following means.
The present invention provides injection locking means for injecting a reference signal having a frequency close to the natural oscillation frequency of the magnetron into the magnetron, and drawing and synchronizing the oscillation frequency of the magnetron with the frequency of the reference signal, and an output phase of the magnetron A feedback control means for comparing the phase of the reference signal with the phase of the reference signal to obtain a phase error between the two and feeding back a control amount for changing the phase of the reference signal to the injection locking means based on the phase error. A microwave generator is provided.

  According to the above configuration, the reference signal having a frequency close to the natural oscillation frequency of the magnetron is injected into the magnetron by the injection locking means. Thereby, the output frequency of each magnetron is drawn to the frequency of this reference signal. On the other hand, a part of the output of the magnetron and a part of the reference signal are input to the feedback control means, where a phase error between them is obtained, and a control amount corresponding to the phase error is fed back to the injection locking means. Then, the reference signal whose phase is adjusted according to the control amount is injected into the magnetron by the injection locking means. By performing feedback control in this manner, the frequency and phase of the magnetron output can be converged to desired values.

  Here, in the above configuration, the output of the magnetron is controlled by changing the phase of the reference signal, not by controlling the output of the magnetron by changing the anode current. Fluctuations and output phase fluctuations can be eliminated. As a result, the synchronization accuracy can be improved.

  In addition, since the anode current is not feedback-controlled, it is possible to provide a high-voltage direct current stabilized power supply that is slow in response outside the feedback loop, so that the responsiveness can be improved. As a result, for example, the time from when the phase synchronization state is lost to when it is synchronized again can be greatly shortened.

  In the microwave generator described above, the injection locking unit includes a variable phase shifter that changes a phase shift amount of the reference signal based on a control amount given from the feedback control unit, and the feedback control unit includes: It is preferable to provide phase shifter control means for comparing the phase error with a preset target phase value and feeding back a control amount corresponding to a deviation from the target phase value to the variable phase shifter.

  According to the above configuration, the phase shifter control means included in the feedback control means obtains a phase error between the output of the magnetron and the reference signal, and further, a deviation amount between the phase error and a preset target phase value. A control amount corresponding to is input to the variable phase shifter provided in the injection locking means. The phase of the reference signal is adjusted by the variable phase shifter according to the control amount given from the phase shifter control means, and the adjusted reference signal is injected into the magnetron. By performing such feedback control, the output phase of the magnetron can be converged to a desired phase.

  In the microwave generator described above, the target phase value changes the phase of the reference signal injected into the magnetron from 0 ° to 360 ° in a state where the feedback control unit is in an open loop, It may be set based on a phase error between the reference signal and the output of the magnetron.

  According to the above configuration, the target phase value is set as follows. First, in a state where the feedback control means is in an open loop, that is, in a state where a predetermined control amount is not fed back to the injection locking means, a reference signal whose phase is changed from 0 ° to 360 ° is injected into the magnetron. Then, the phase error between the output of the magnetron and the reference signal at this time is measured, and the median value of the measurement result is set as the target phase value.

  As described above, since the target phase value is set without changing the anode current of the magnetron, it becomes possible to eliminate the offset error of the target phase value caused by the change in the output amplitude of the magnetron. Thereby, since feedback control is performed based on the target phase value set with high accuracy, the synchronization system can be further improved.

  The present invention injects a plurality of magnetrons and a reference signal having a frequency close to the natural oscillation frequency of each of the magnetrons into the plurality of magnetrons, and draws the oscillation frequencies of the plurality of magnetrons into the frequency of the reference signal. Injection locking means for synchronizing with each other, a hybrid power combining circuit for combining and outputting the outputs of the plurality of magnetrons, and a combined output of the plurality of magnetrons combined with the hybrid power combining circuit and a phase of the reference signal And a feedback control unit that feeds back a control amount for changing the phase of the reference signal based on the phase error to the injection locking unit. .

  According to the above configuration, the reference signal having a common frequency close to the natural oscillation frequency of the magnetron is injected into the plurality of magnetrons by the injection locking means. As a result, the output frequency of each magnetron is drawn into the frequency of the reference signal, and this output is synthesized by the hybrid power synthesis circuit and output. The combined output of the hybrid power combiner circuit and the reference signal are input to the feedback control means, where the phase error between the two is obtained, and the control amount corresponding to this phase error is fed back to the injection locking means. The reference signal whose phase is adjusted according to the amount is injected into the magnetron by the injection locking means. By performing feedback control in this way, the output frequency and output phase of each magnetron can be converged to desired values.

  In this case, in the above configuration, the outputs of the individual magnetrons are combined by a hybrid power combining circuit, and feedback control is performed based on the combined output. Therefore, a phase shift control circuit or a circulator used for phase control, etc. It is possible to reduce various components.

  The phase of the outputs of the plurality of magnetrons synthesized by the hybrid power synthesis circuit is, for example, the center phase of the output phases of the magnetrons. Further, the amplitudes of the outputs of the plurality of magnetrons synthesized by the hybrid power synthesis circuit are determined by, for example, the relative phases of the outputs of the magnetrons.

  In the microwave generator described above, the temperature of the magnetron is set to a target temperature value at which an error between the frequency of the reference signal and the natural oscillation frequency of the magnetron is zero. It is preferable to further include temperature adjusting means for adjusting.

The output phase of the magnetron changes depending on the temperature of the magnetron and fluctuates due to disturbances such as changes in the outside air temperature.
Therefore, according to the above configuration, the temperature of the magnetron is detected by the temperature detection means, and the temperature of the magnetron is set to a target temperature value at which the error between the frequency of the reference signal and the natural oscillation frequency of the magnetron becomes zero by the temperature adjustment means. Since the adjustment is performed, it is possible to eliminate an error in the output phase caused by the temperature. As a result, the accuracy of the synchronization control can be further improved.

  The present invention is a microwave power transmission device including an oscillation module that oscillates microwaves and a power transmission antenna that transmits microwaves oscillated by the oscillation module, and is provided between the oscillation module and the power transmission antenna. A microwave power transmission device provided with output control means for controlling the output direction of the microwave from the oscillation module so as to avoid unnecessary radiation from the power transmission antenna during calibration for initial adjustment of the oscillation module provide.

  According to the above configuration, during calibration for initial adjustment of the oscillation module, the microwave output direction from the oscillation module is controlled so as to avoid unnecessary radiation from the power transmission antenna. It becomes possible to suppress.

  In the microwave power transmitting apparatus described above, the oscillation module is configured to inject a reference signal having a frequency close to a natural oscillation frequency of the magnetron into the magnetron, and to inject and synchronize the oscillation frequency of the magnetron with the frequency of the reference signal. And a phase error of the reference signal by comparing the oscillation output of the magnetron and the phase of the reference signal, and a control amount for changing the phase of the reference signal based on the phase error is fed back to the injection locking means. Feedback control means may be provided.

  According to the above configuration, the output phase of the magnetron is compared with the phase of the reference signal, and the phase of the reference signal is changed based on the phase error between the two, so the output of the magnetron can be referred to without changing the anode current. It becomes possible to draw in the signal. This makes it possible to realize stable phase control even for a magnetron in which the relationship between the anode current and the output phase is nonlinear. As a result, stable control can be realized regardless of the product deviation of the magnetron.

Furthermore, since the anode current is not changed, the output amplitude of the magnetron during the phase control of the magnetron does not change. As a result, the amplitude stability can be improved.
In addition, since it is possible to provide a high-voltage direct current stabilized power supply having a slow response outside the feedback loop, it is possible to improve the responsiveness. As a result, it is possible to significantly reduce the time from when the phase is out of synchronization to when it is synchronized again.

  The present invention relates to a solar power generation panel provided in outer space, a microwave generator that generates microwaves by receiving electric power generated by the solar power generation panel, and a microwave output from the microwave generator The microwave generator includes a power transmission antenna that injects a reference signal having a frequency close to the natural oscillation frequency of the magnetron into the magnetron, and sets the oscillation frequency of the magnetron to the frequency of the reference signal. An injection locking means for pulling in and synchronizing, and comparing the output phase of the magnetron and the phase of the reference signal to obtain a phase error between them, and a control amount for changing the phase of the reference signal based on the phase error Provided is a space solar power generation system comprising feedback control means for feeding back to the injection locking means That.

The space solar power generation system described above is provided between the microwave generator and the power transmission antenna so as to avoid unnecessary radiation from the power transmission antenna during calibration for initial adjustment of the microwave generator. It is preferable to further include output control means for controlling the output direction of the microwave from the microwave generator.
Accordingly, it is possible to suppress unnecessary emission of microwaves during calibration for initial adjustment of the microwave generator.

  According to the microwave generation device, the microwave power transmission device, and the space solar power generation system of the present invention, it is possible to improve the phase synchronization accuracy and the responsiveness.

Hereinafter, embodiments of a microwave generator according to the present invention will be described in the order of [First Embodiment], [Second Embodiment], and [Third Embodiment] with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a schematic configuration of a microwave generator according to a first embodiment of the present invention.
As shown in FIG. 1, the microwave generator according to the present embodiment includes an injection locking circuit (injection locking means) 20 and a feedback control circuit (feedback control means) 21. The injection locking circuit 20 is configured to inject a reference signal having a frequency close to the natural oscillation frequency of the magnetron 1 into the magnetron 1 and to synchronize the oscillation frequency of the magnetron 1 with the frequency of the reference signal. The signal generator 3, the distributor 5, the second variable phase shifter 6, and the circulator 8 are configured.
Further, the feedback control circuit 21 compares the output phase of the magnetron 1 with the phase of the reference signal to determine the phase error between the two, and based on the phase error, the control amount for changing the phase of the reference signal is injected. For example, it includes a mixer 9, a phase shifter control circuit 12, an initial calibration calculator 13, and a switch 14 which will be described later.

In such a microwave generator, an anode current is caused to flow between the anode (anode) and the cathode (cathode) of the magnetron 1 by the high-voltage direct current stabilizing power source 2, thereby setting the magnetron 1 in an oscillation state. The
The reference signal generator 3 generates a reference signal having a frequency close to the natural oscillation frequency of the magnetron 1, and the generated reference signal is supplied to the distributor 5 via the first variable phase shifter 4. Is done. The distributor 5 distributes the inputted reference signal into two systems, and the reference signal of one system is supplied to the circulator 8 via the second variable phase shifter 6 and the high frequency amplifier 7, and the other system The system reference signal is supplied to the mixer 9.

  The circulator 8 inputs a reference signal supplied from the distributor 5 from a first terminal (not shown), outputs the reference signal from a second terminal (not shown), and injects it into the magnetron 1. The radiated microwave is taken in from the second terminal (not shown) and output from the third terminal (not shown). The microwave output from the circulator 8 is output to the outside via the directional coupler 10, and a part of the microwave is branched and output to the attenuator 11.

  A part of the microwaves input to the attenuator 11 is attenuated and supplied to the mixer 9. The mixer 9 mixes the reference signal from the distributor 5 and the microwave from the attenuator 11, and a part corresponding to the phase difference between these two input signals (for example, the first of the above-described equation (1)). Term) and an offset component depending on the input level of each signal (for example, the second term of the above-described equation (1)) is added and output.

The output from the mixer 9 is input to the phase shifter control circuit 12. During operation, the phase shifter control circuit 12 compares the output from the mixer 9 with a target value (Vref) preset in the initial calibration calculator 13 and switches the deviation from the target value Vref to the switch 14. Is fed back to the second variable phase shifter 6. Here, for example, as shown in FIG. 2, the phase shifter control circuit 12 receives the target value Vref at the + side input terminal, and outputs the mixer 9 to the − side input terminal, that is, the reference signal and the microwave. And a differential amplifier circuit 121 that outputs in accordance with the difference, and an integrator circuit 122 that receives the output of the differential amplifier circuit 121 and integrates and outputs the input. Has been.
The initial calibration computing unit 13 is a computing device used when setting the target value Vref, and includes, for example, a microcomputer having a CPU or the like. The details of the target value Vref set by the initial calibration calculator 13 will be described later.

The switch 14 is a switch for switching the feedback loop by the phase shifter control circuit 12 to an open loop or a closed loop. At the time of initial calibration, the switch 14 is connected to the initial calibration computing unit 14 to open the feedback loop. In the operation, the feedback loop is closed by connecting to the second variable phase shifter 6 during operation.
In operation, the second variable phase shifter 6 changes the phase shift amount of the reference signal so as to complement the deviation input from the phase shifter control circuit 12. Thereby, the output phase of the magnetron 1 is synchronized with the phase of the reference signal.

Next, the processing operation of the microwave generator having the above-described configuration will be described.
First, it is assumed that the magnetron 1 is in an oscillating state when an anode current is passed by the high-voltage direct current stabilizing power source 2. In this state, a reference signal generated by the reference signal generator 3 and having a frequency close to the natural oscillation frequency of the magnetron 1 is injected into the magnetron 11 via the variable phase shifter 6, the high frequency amplifier 7, and the circulator 8. . As a result, the oscillation frequency of the magnetron 1 is drawn into the frequency of the reference signal.

  The microwave radiated from the magnetron 1 is output to the outside via the circulator 8 and the directional coupler 10 and a part of the microwave is output to the attenuator 11. The microwave attenuated by the attenuator 11 is input to the mixer 9. Then, the mixer 9 mixes the reference signal from the distributor 5 and the microwave from the attenuator 11, and a portion corresponding to the phase difference between these two input signals and an offset component depending on the input level of each signal. The added output is sent to the phase shifter control circuit 12. In the phase shifter control circuit 12, the output from the mixer 9 and the preset target value Vref are compared to determine a deviation from the target value Vref, and a control amount corresponding to this deviation causes the switch 14 to switch. Via the second variable phase shifter 6.

Then, the phase shift amount of the reference signal is changed by the second variable phase shifter 6 so as to complement the deviation fed back from the phase shifter control circuit 12, and the reference signal after the phase shift amount change is similarly changed. It is injected into the magnetron 1 via the high frequency amplifier 7 and the circulator 8.
In this way, by controlling the phase of the reference signal by the feedback loop, the oscillation frequency of the magnetron 1 can be matched with the reference signal and the phase can be locked.

Next, the target value Vref handled by the phase shifter control circuit 12 is determined as follows at the time of initial calibration.
First, at the time of initial calibration, the switch 14 is connected to the initial calibration computing unit 13, whereby the feedback loop is opened. In this state, Vref used by the phase shifter control circuit 12 is set to zero, the phase shift amount of the second variable phase shifter 6 is changed from 0 ° to 360 °, and the phase shifter control circuit 12 at that time is changed. Is output by the initial calibration calculator 13. Accordingly, the measurement result obtained by the initial calibration calculator 13 draws a curve as shown in FIG. 3, for example.

  Here, in FIG. 3, the horizontal axis indicates the phase shift amount of the second variable phase shifter 6, and the vertical axis indicates the output of the phase shifter control circuit 12. As shown in this figure, the output of the phase shifter control circuit 12 draws a sine wave (or cosine wave) corresponding to the phase shift amount (0 ° to 360 °) of the second variable phase shifter 6. It becomes. Then, the initial calibration calculator 13 obtains a median value as shown in FIG. 3 in the output of the phase shifter control circuit 12 thus obtained, and sets this value as the target value Vref.

Here, in the microwave generator of the present embodiment shown in FIG. 1, a conventional microwave generator that converges the output of the magnetron by feedback controlling the anode current supplied to the magnetron 1 (see, for example, FIG. 12). Unlike), the anode current of the magnetron 1 is not changed during the initial calibration. For this reason, it becomes possible to eliminate the fluctuations in the phase and amplitude of the magnetron 1, which has been a problem in the conventional microwave generator described above. Thus, for example, the amplitude A ₂ of the microwave becomes not changed in the first and second terms in the above-mentioned (1), determining an offset component ((1) the second term in the equation) with high accuracy Is possible. As a result, it is possible to set the target value Vref with high accuracy, and thus it is possible to perform the above-described feedback control during operation with high accuracy. Thereby, the accuracy of the phase synchronization control can be improved.

As described above, according to the microwave generator according to the present embodiment, since the output of the magnetron 1 is controlled without changing the anode current, the synchronization accuracy can be improved. Furthermore, since the output control of the magnetron is performed without changing the anode current, the fluctuation of the output amplitude can be eliminated. Thereby, for example, when configuring an active phased array, the excitation amplitude distribution on the power transmission surface does not fluctuate, and deterioration of the radiation pattern can be prevented.
Further, since the high-voltage direct current stabilized power supply 2 having a slow response is provided outside the feedback loop, the responsiveness can be improved. As a result, it is possible to significantly reduce the time from when the phase is out of synchronization to when it is synchronized again.

[Second Embodiment]
Next, a microwave generator according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a diagram showing a schematic configuration of the microwave generator according to the present embodiment.
In this figure, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 4, the microwave generator according to the present embodiment includes a plurality of magnetrons 1a and 1b, and operates to converge the output frequency and phase of these magnetrons 1a and 1b to desired values. To do.
Here, the microwave generator according to the present embodiment includes an injection locking circuit (injection locking means) 20a, a hybrid power combining circuit 30, and a plurality of feedback control circuits (feedback control means) 21a and 21b. Yes.

  The injection locking circuit 20a injects a common reference signal (hereinafter referred to as “common reference signal”) having a frequency close to the natural oscillation frequency of the magnetron into the plurality of magnetrons 1a and 1b. The oscillation frequency of 1b is pulled in and synchronized with the frequency of the common reference signal. The injection locking circuit 20a is substantially the same as the injection locking circuit 20 according to the first embodiment described above. For example, a reference signal generator (not shown) for generating a common reference signal, and distributing and outputting the reference signal And a distributor 5, a variable phase shifter 6, a high-frequency amplifier 7, a circulator 8, and the like.

  The hybrid power combining circuit 30 injects the common reference signal into each of the magnetrons 1a and 1b, and combines and outputs the outputs of the plurality of magnetrons 1a and 1b. In the present embodiment, the port P1 of the hybrid power combining circuit 30 is connected to the magnetron 1a, and the port P2 is connected to the magnetron 1b via the waveguide phase shifter 31. Further, the port 3 is connected to the circulator 8 of the synchronous injection circuit 20a, whereby a common reference signal is input from the port 3. The port P4 is connected to the directional coupler 10a in order to output the combined output of the magnetrons 1a and 1b to the outside.

  Here, as shown in FIG. 5, the hybrid power combining circuit 30 has the following performance. For example, a signal input from the port P3 is equally distributed to the ports P1 and P2 and is output as a reverse phase signal. The signal input from the port P4 is equally distributed to the ports P1 and P2 and is output as an in-phase signal. On the other hand, when signals having opposite phases and the same magnitude are input from the ports PP1 and P2, a combined output appears at the port P3. When signals having the same phase and the same magnitude are input from the ports P1 and P2, a combined output appears at the port P4.

  In the present embodiment, the microwaves output from the magnetrons 1a and 1b are combined by the hybrid power combining circuit 30 and output to the port P4. The combined output at this time is as shown in FIG. The phase changes with the center phase of each microwave, and the amplitude changes with the relative phase difference of each microwave.

Next, the feedback control circuit 21a, which is a component of the microwave generator according to the present embodiment, includes the combined outputs of the plurality of magnetrons 1a and 1b combined by the hybrid power combining circuit 30 and the phase of the common reference signal. And a control amount for changing the phase of the reference signal based on the phase error is fed back to the injection locking circuit 20a. For example, the mixer 9 and the first phase shifter control circuit 12a.
The feedback control circuit 21b controls the waveguide phase shifter 31 provided between the magnetron 1b and the hybrid power combining circuit 30. For example, the feedback control circuit 21b includes a rectifier circuit 32 and a rectifier circuit 32. Is provided with a second phase shifter control circuit 12b that obtains a predetermined control amount based on the output of, and feeds back this control amount to the waveguide phase shifter 31.

In the microwave generator of the present embodiment having such a configuration, the magnetrons 1a and 1b are connected to the high-voltage direct current stabilized power sources 2a and 2b, respectively, and the high-voltage direct current stabilized power sources 2a and 2b are connected to the anodes. The current is supplied to the magnetrons 1a and 1b, so that the magnetrons 1a and 1b are oscillated.
On the other hand, a common reference signal generated by a reference signal generator (not shown) constituting the injection locking circuit 20a is distributed to two systems by the distributor 5, and the common reference signal of one system is the variable phase shifter 6. The signal is supplied to the circulator 8 through the high-frequency amplifier 7, and the reference signal of the other system is supplied to the mixer 9 of the first feedback control circuit 21a.

  The circulator 8 inputs a common reference signal supplied from the distributor 5 from a first terminal (not shown), outputs the common reference signal from a second terminal (not shown), and the hybrid power combining circuit. Inject into 30 ports P3. As a result, the common reference signal injected into the port P3 is distributed by the hybrid power combining circuit 30 and is output to the port 1 and the port P2 as opposite phase signals. The common reference signal output to the port P1 is injected into the magnetron 1a, and the reverse-phase common reference signal output to the port P2 is rotated 90 ° by the waveguide phase shifter 31 and injected into the magnetron 1b. The

Subsequently, the microwave radiated from the magnetron 1a is taken in from the port P1 of the hybrid power synthesis circuit 30, while the microwave radiated from the magnetron 1b is hybridized via the waveguide phase shifter 31. It is taken in from the port P2 of the power combining circuit 30. The hybrid power combining circuit 30 combines the microwaves input from the ports P1 and P2 and outputs the combined microwave from the port P4. The combined output that is output at this time is as described with reference to FIG.
In this way, the combined output of the magnetrons 1a and 1b output from the port P4 is output to the outside via the directional coupler 10a, and a part of the output is branched to allow the first feedback control circuit 21a to pass through. While being input to the mixer 9 which comprises, it is input into the 21 rectifier circuit 32 which comprises the 2nd feedback control circuit 21b.

  In the first feedback control circuit 21a, the mixer 9 mixes the reference signal input via the distributor 5 and the combined output input from the directional coupler 10a, and the first feedback control circuit 21a described above. Similar to the microwave generator according to the embodiment, an output in which a portion corresponding to the phase difference between these two input signals and an offset component depending on the input level of each signal are added is obtained. The output of the mixer 9 is input to the first phase shifter control circuit 12a, and the output from the mixer 9 is compared with a preset target value Vref to obtain a deviation from the target value Vref. Then, a control amount corresponding to this deviation is fed back to the variable phase shifter 6. The target value Vref used here is set by the same method as in the first embodiment described above.

  On the other hand, in the second feedback control circuit 20b, the combined output input to the rectifier circuit 32 is converted into a direct current component and input to the second phase shifter control circuit 12b. The second phase shifter control circuit 12b feeds back the control amount corresponding to the direct current component to the waveguide phase shifter 31, so that the combined output can be converged to a constant target value.

  In this way, the control amount corresponding to the combined output of the magnetrons 1a and 1b is fed back to the phase shift amount of the common reference signal, so that the output frequencies and output phases of the magnetrons 1a and 1b gradually become desired values. It will be converged to.

As described above, according to the microwave generator according to the present embodiment, the outputs of the individual magnetrons 1a and 1b are combined by the hybrid power combining circuit 30, and feedback control is performed based on the combined output. Therefore, it is possible to reduce various components such as a phase shift control circuit and a circulator used for phase control. As a result, the number of parts can be greatly reduced, so that the efficiency of the apparatus, weight reduction, and cost reduction can be achieved.
In the above-described embodiment, the microwave generator including two magnetrons as an example has been described. However, the number of magnetrons is not limited to this example, and a large number of magnetrons may be provided. In the above embodiment, the hybrid power combining circuit 30 having four ports is used. However, the present invention is not limited to this example, and an eight-port power combining circuit can also be adopted.

[Third Embodiment]
Next, the microwave generator which concerns on the 3rd Embodiment of this invention is demonstrated using figures. FIG. 7 is a diagram showing a schematic configuration of the microwave generator according to the present embodiment. In this figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, the microwave generator according to the present embodiment further includes a thermocouple (temperature detection means) 41 that detects the temperature of the magnetron in addition to the microwave generator according to the first embodiment described above. A temperature adjusting device (temperature adjusting means) 42 for adjusting the temperature of the magnetron based on the temperature of the magnetron detected by the thermocouple 41 is provided. The temperature adjustment device 42 includes, for example, a magnetron temperature control circuit 421, a thermo module drive power supply 422, a thermo module 423, and the like. In addition, a radiation plate 43 for radiating heat is connected to the thermo module 423 via a heat pipe.

  Further, a distributor 44 is disposed between the switch 14 in the feedback control circuit 21 and the initial calibration calculator 13. As a result, the output of the phase shifter control circuit 12 at the time of calibration is input to the distributor 44 via the switch 14 and is distributed to two systems where one system is supplied to the initial calibration computing unit 13 and the other system. Is input to the magnetron temperature control circuit 421.

  Hereinafter, the microwave generator of the present embodiment having such a configuration will not be described for the points common to the first embodiment, and only different points will be described.

First, at the time of initial calibration, the switch 14 is connected to the distributor 44, whereby the feedback control circuit 21 is brought into an open loop state. Further, by connecting the switch 14 in this way, the output of the phase shifter control circuit 12 is input to the initial calibration calculator 13 and the magnetron temperature control circuit 421 via the distributor 44.
Next, in such a circuit configuration, a reference signal is oscillated from the reference signal generator 3, and this reference signal is input to the distributor 5 through the first variable phase shifter 4, thereby 2 Distributed to the grid. As a result, the distributed system is supplied to the mixer 9 and the other system is injected into the magnetron 1 via the second variable phase shifter, the high frequency amplifier 7 and the circulator 8.

  When the reference signal is injected as described above, the high voltage direct current stabilizing power supply 2 applies an anode current to the magnetron 1 in a state where the cooling of the magnetron 1 by the temperature adjusting device 42 is not performed, thereby causing the magnetron 1 to oscillate. As a result, the output of the magnetron 1 is input to the mixer 9 via the circulator 8, the directional coupler 10, and the attenuator 11, as described above. Then, the mixer 9 compares the reference signal with the output of the magnetron, and the comparison result is input to the phase shifter control circuit 12, so that the phase error is passed through the switch 14 and the initial calibration calculator 13 and the magnetron. It is input to the temperature control circuit 421.

Here, as shown in FIG. 8, the spectrum of the output frequency of the magnetron 1 gradually falls as the temperature of the magnetron 1 rises, so that it enters the pull-in range by the reference signal, and eventually falls outside the pull-in range. That frequency will drop. On the other hand, the output characteristic of the phase shifter control circuit 12 at this time shows a curve as shown in FIG.
The magnetron temperature control circuit 421 refers to the frequency spectrum shown in FIG. 8 and the output characteristics of the phase shifter control circuit 12 shown in FIG. 9, so that the magnetron temperature Ta when the magnetron output frequency falls within the pull-in range. In addition, the magnetron temperature Tb when the output frequency of the magnetron is out of the pull-in range is obtained, and the magnetron temperature control circuit 421 obtains the median value of the obtained temperatures Ta and Tb, and this median value is obtained from the magnetron 1 Set to the target temperature value. In FIG. 9, the horizontal axis represents the temperature of the magnetron 1 and the vertical axis represents the output of the phase shifter control circuit 12.

  When the target temperature value is set in this way, the magnetron temperature control circuit 421 sends a control signal such that the temperature of the magnetron 1 detected by the thermocouple 41 matches the target temperature value to the thermomodule drive power source 422. Output to. Thus, the thermomodule driving power source 422 drives the thermomodule 423 based on this control signal, so that the temperature of the magnetron 1 can be maintained at the target temperature value.

  Then, in such a state that the temperature control of the magnetron 1 is being performed, the setting of the target value Vref at the time of the initial calibration described in the first embodiment is performed by the initial calibration calculator 13 or the like. . When the setting of the target value Vref at the time of initial calibration is completed, the switch 14 is connected to the second variable phase shifter 6, whereby the feedback loop becomes a closed loop, and feedback control by the feedback control circuit 21 is performed. The Rukoto.

  As described above, according to the microwave generator according to the present embodiment, the fluctuation of the output phase of the magnetron 1 due to the temperature change of the magnetron 1 can be eliminated. The value Vref can be set with high accuracy, and the temperature of the magnetron 1 is maintained at the target temperature value by the temperature adjustment device 42 even during operation. Therefore, the accuracy of the synchronous control can be further improved. It becomes possible.

Next, an embodiment of a microwave power transmission device according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 10, the microwave power transmission device according to an embodiment of the present invention includes an oscillation module 51 that includes a plurality of the microwave generation devices according to the above-described embodiments and oscillates a powerful microwave. ing. The oscillation module 51, for example, a magnetron 1 10 about ^six. The microwave output from the oscillation module 51 is distributed to the power by being input to the port P1 of the first power combining circuit 52.

A part of the microwave distributed by the first power combining circuit 52 is directly input to the port P1 of the second power combining circuit 53, and the other part is passed through the waveguide phase shifter 54. And input to the port P2 of the second power combining circuit 53. The second power combining circuit 53 recombines the microwaves from the first power combining circuit 52 input from the ports P1 and P2, and outputs the output to the matching terminal 55 connected to the port P3 or the port P4. It outputs to the directional coupler 56 connected. The microwave output to the directional coupler 56 is output to the outside by the power transmission antenna 57. Here, as the first power combining circuit 52 and the second power combining circuit 53, for example, the hybrid power combining circuit 30 used in the microwave generator according to the second embodiment described above is used. .
The waveguide phase shifter 54 provided between the first power combining circuit 52 and the second power combining circuit 53 is based on the output set value output from the output control circuit (output control means) 58. Controlled by the phase shifter control circuit 59.

  A microwave power transmission apparatus having such a configuration is applied to a space solar power generation system, for example, as shown in FIG. 11, and generates electric power generated by receiving sunlight from a large solar cell panel. It is used to convert to microwave and transmit this microwave to the ground.

  In the microwave power transmitting apparatus having such a configuration, the output control circuit 58 prevents unnecessary radiation of the microwave to the power transmitting antenna 57 at the time of initial calibration of each microwave generating apparatus constituting the oscillation module 51. Then, an output set value is generated so that the output of the second power combining circuit 53 is taken out to the matching terminal 55, and this is output to the phase shifter control circuit 59.

  Thus, the phase shifter control circuit 59 controls the waveguide phase shifter 54 based on the output set value from the output control circuit 58, so that the microwave from the first power combining circuit 52 is Therefore, the power is not supplied to the power transmitting antenna 57. Thereby, it is possible to avoid the microwaves being emitted to the outside via the power transmission antenna 57 during the initial calibration for setting the target value Vref and the target temperature value.

  When the above-described initial calibration is completed and feedback control is performed by the feedback control device 21 (see FIG. 1) constituting the above-described microwave generation device, the output control circuit 58 receives the microwave from the oscillation module 51. Is output to the phase shifter control circuit 59 so as to be supplied to the power transmission antenna 57. Thereby, the waveguide phase shifter 54 is controlled by the phase shifter control circuit 59, so that the microwave from the oscillation module 51 is converted into the first power combining circuit 52, the second power combining circuit 53, Then, the power is supplied to the power transmission antenna 57 via the directional coupler 56, and the microwave is radiated to the outside by the power transmission antenna 57.

  As described above, according to the microwave power transmission device according to the present embodiment, the oscillation module 51 is arranged so as to avoid unnecessary radiation from the power transmission antenna 57 at the time of initial calibration for performing the initial adjustment of the oscillation module 51. Since the output direction of the microwave from is controlled by the output control circuit 59, it is possible to suppress unnecessary radiation of the microwave.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

1 is a schematic configuration diagram of a microwave generator according to a first embodiment of the present invention. FIG. 2 is a circuit diagram illustrating an example of an internal configuration of a phase shifter control circuit in FIG. 1. It is a figure which shows the output characteristic of the phase shifter control circuit referred when determining the target value in the time of initial calibration in the microwave generator which concerns on the 1st Embodiment of this invention. It is a schematic block diagram of the microwave generator which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the input-output about the hybrid type | mold electric power synthesis circuit shown in FIG. FIG. 5 is a diagram for describing an output combined by the hybrid power combining circuit illustrated in FIG. 4. It is a schematic block diagram of the microwave generator which concerns on the 3rd Embodiment of this invention. It is the figure which showed transition of the frequency spectrum when the temperature of a magnetron is changed in the microwave generator which concerns on the 3rd Embodiment of this invention. It is the figure which showed the output characteristic of the phase shifter control circuit when the temperature of a magnetron was changed in the microwave generator which concerns on the 3rd Embodiment of this invention. It is a figure which shows schematic structure of the microwave power transmission apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating a space solar power generation system. It is the figure which showed one schematic structure of the conventional microwave generator.

Explanation of symbols

1 Magnetron 2 High Voltage Current Stabilized Power Supply 3 Reference Signal Generator 6 Second Variable Phase Shifter 8 Circulator 9 Mixer 12 Phase Shifter Control Circuit 13 Initial Calibration Calculator 14 Switch 20 Injection Locking Circuit 21 Feedback Control Circuit 30 Hybrid Type Power synthesis circuit 41 Thermocouple 42 Temperature adjustment device 51 Oscillation module 57 Power transmission antenna 58 Output control circuit 421 Magnetron temperature control circuit

Claims (9)

Injection locking means for injecting a reference signal having a frequency close to the natural oscillation frequency of the magnetron into the magnetron, and pulling and synchronizing the oscillation frequency of the magnetron with the frequency of the reference signal;
Feedback control for comparing the output phase of the magnetron and the phase of the reference signal to obtain a phase error between them, and feeding back a control amount for changing the phase of the reference signal to the injection locking means based on the phase error And a microwave generator. The injection locking unit includes a variable phase shifter that changes a phase shift amount of the reference signal based on a control amount given from the feedback control unit,
The feedback control means is a phase shifter control means for comparing the phase error with a preset target phase value and feeding back a control amount corresponding to a deviation from the target phase value to the variable phase shifter. The microwave generator of Claim 1 provided.   The target phase value changes the phase of the reference signal injected into the magnetron from 0 ° to 360 ° in a state where the feedback control means is in an open loop, and the reference signal and the output of the magnetron at this time The microwave generator according to claim 1 or 2, wherein the microwave generator is set based on a phase error. Multiple magnetrons,
Injection locking means for injecting a reference signal having a common frequency close to the natural oscillation frequency of each of the magnetrons to the plurality of magnetrons, and drawing and synchronizing the oscillation frequencies of the plurality of magnetrons to the frequency of the reference signal; ,
A hybrid power combining circuit that combines and outputs the outputs of the plurality of magnetrons;
Control that compares the combined output of the plurality of magnetrons combined by the hybrid power combining circuit and the phase of the reference signal to obtain a phase error between them, and changes the phase of the reference signal based on the phase error And a feedback control means for feeding back the amount to the injection locking means. Temperature detecting means for detecting the temperature of the magnetron;
The temperature adjusting means for adjusting the temperature of the magnetron to a target temperature value at which an error between the frequency of the reference signal and the natural oscillation frequency of the magnetron becomes zero is provided. The microwave generator described in 1. A microwave power transmission apparatus comprising: an oscillation module that oscillates microwaves; and a power transmission antenna that transmits microwaves oscillated by the oscillation module,
Provided between the oscillation module and the power transmission antenna and control the output direction of the microwave from the oscillation module so as to avoid unnecessary radiation from the power transmission antenna during calibration for initial adjustment of the oscillation module A microwave power transmission apparatus comprising output control means for performing the operation. The oscillation module is
Injection locking means for injecting a reference signal having a frequency close to the natural oscillation frequency of the magnetron into the magnetron and pulling and synchronizing the oscillation frequency of the magnetron with the frequency of the reference signal;
A feedback control unit that compares the oscillation output of the magnetron and the phase of the reference signal to obtain a phase error between them, and feeds back a control amount for changing the phase of the reference signal based on the phase error to the injection locking unit The microwave power transmission device according to claim 6, further comprising: Solar power panels installed in outer space,
A microwave generator for generating microwaves by receiving the electric power generated by the solar power generation panel;
A space solar power generation system comprising: a power transmission antenna that transmits microwaves output from the microwave generator;
The microwave generator is
Injection locking means for injecting a reference signal having a frequency close to the natural oscillation frequency of the magnetron into the magnetron and pulling and synchronizing the oscillation frequency of the magnetron with the frequency of the reference signal;
Feedback control means for comparing the output phase of the magnetron and the phase of the reference signal to obtain a phase error between them, and feeding back a control amount for changing the phase of the reference signal based on the phase error to the injection locking means And a space solar power generation system.   Provided between the microwave generation device and the power transmission antenna, during calibration for initial adjustment of the microwave generation device, the microwave from the microwave generation device is avoided so as to avoid unnecessary radiation from the power transmission antenna. A space solar power generation system comprising output control means for controlling the wave output direction.

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