JP3171406B2 - Power supply for traveling wave tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a traveling wave tube,
In particular, the present invention relates to a traveling wave tube power supply device with reduced ripple.

2. Description of the Related Art A traveling-wave tube used in an amplifier in a microwave band not only heats a filament but also needs to supply a high voltage with respect to a cathode to each electrode, that is, a collector, an anode, and a helix. These three types of high voltage power supplies must be independently set and stabilized in voltage. By the way, the helix electrode of the traveling wave tube is generally grounded for the purpose of adjustment and protection, so that a high voltage for the helix is reflected and applied to the cathode. Therefore, the potential of the cathode becomes about 10 kV, and the collector power, anode power and filament power floatingly charged at the high potential are driven by the high frequency inverter via the insulating transformer. In the traveling wave tube power supply device configured as described above, since the high frequency high voltage circuit is floatingly charged, the floating high frequency component flows to the ground through the floating capacitance, and is then loaded. To return to the cathode potential of the power supply. That is, the high frequency component is applied as an output ripple between the helix and the cathode of the traveling wave tube. Ripple of the power supply causes spurious emission of the traveling wave tube, so it is necessary to reduce the ripple. In order to reduce the output ripple, there is a method of connecting a capacitor in parallel between the output terminals. The capacitance of this capacitor works to increase the instantaneous current to the traveling wave tube and shortens the life of the tube. This is undesirable.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce inductive output ripple in a traveling wave tube power supply without increasing the capacitance of an output circuit.

SUMMARY OF THE INVENTION In order to solve such problems, the present invention comprises a high-frequency inverter, an insulating transformer and a rectifier circuit driven by the high-frequency inverter, and a helical electrode of a traveling-wave tube. What is claimed is: 1. A traveling wave tube power supply device comprising a high voltage generator for supplying power to a collector electrode, wherein the high voltage generator is covered by a first conductor via an insulating medium, and the first conductor is a traveling wave. The first means is to connect the cathode to the cathode potential of the tube, and to cover the first conductor with the second conductor via an insulator and connect to ground. As a second means, the high-voltage generating section of such a traveling-wave tube power supply device is covered with a conductor via an insulating medium, and the conductor is grounded via an impedance element and connected via a capacitor. It is proposed to connect to the cathode of a traveling wave tube.

With any of the above-mentioned means, since a high-frequency source for providing an inductive high-frequency ripple to the output forms a closed circuit by a conductive material included before the output circuit, almost no high-frequency ripple appears in the output circuit.

FIG. 1 is a diagram showing a first embodiment of the present invention. First, the configuration will be described. The high frequency inverter 1 is connected to the primary winding of the transformer 3 and supplies a high frequency of about 20 kHz. The secondary winding of the transformer 3 is composed of diodes 17, 19, 21,
It is connected to a bridge rectifier circuit 18 composed of 23. A capacitor 25 is connected in parallel to an output terminal of the bridge rectifier circuit 18, a positive output is connected to a terminal 37, and a negative output is connected to a terminal 35. Further, the secondary winding of the transformer 3 is also connected to a voltage doubler rectifier circuit 20 including a capacitor 27, diodes 29 and 31 and a capacitor 33 at the same time. This voltage doubler rectifier
The negative output terminal 20 is common to the bridge rectifier circuit 18 and the terminal 35
And the positive output terminal is connected to terminal 39. On the other hand, the traveling wave tube 43 comprises a filament 44, a cathode 45, a helix 47, and a collector 49. The filament 44 is supplied from an insulated power source (not shown), and the cathode 45 is connected to a terminal.
Helix 47 is connected to terminal 39, and collector 49 is connected to terminal 37. Here, the high voltage generator 6 including the transformer 3, the bridge rectifier circuit 18, and the voltage doubler rectifier circuit 20 is covered by the shield case 5, and one end thereof is connected to the terminal 35. Further, the outer periphery of the shield case 5 is further covered by the grounding case 7 with an insulating medium interposed, and one end thereof is grounded by the grounding 41. In the traveling wave tube power supply device 8 configured as described above, the transformer 3
The AC component induced from the next winding 4 is configured as an equivalent circuit in which the internal AC source e is divided by a capacitor as shown in FIG. In the embodiment shown in FIG. 1A, the stray capacitance Cs becomes almost zero due to the shield case 5 connected to the terminal 35 serving as the reference potential point, so that the output ripple eo has a very small value.

Second Embodiment FIG. 2 shows a second embodiment of the present invention.
In FIG. 2, elements with the same reference numerals as those in FIG. 1 correspond to elements with the same reference numerals. The difference between the second embodiment and the first embodiment is that there is no shield case 5 and the case 7 'has the same function as the shield case 5, which is a structural difference. That is, the case 7 ′ is connected to the inductor 55
And a parallel circuit of the varistor 53 are connected in series and connected to the terminal 39. Then, the case 7 ′ is connected to the terminal 35 via the capacitor 51.
Connect to In the traveling wave tube power supply device 8 configured as described above, the case 7 ′ is grounded and connected to the ground via the inductor 55 and the terminal 39. On the other hand, a protective ground plane is formed.
In terms of alternating current, the potential is raised from the ground point by the reactance component of the inductor 55 and almost coupled to the potential of the terminal 35 by the capacitor 51.
Has the same function as the shield case 5 in the first embodiment. Therefore, the output ripple eo due to the AC component induced from the secondary winding 4 of the transformer 3 has a very small value. In the circuit shown in FIG. 2, the inductor 55 may be another impedance element, for example, a resistor or a combination circuit of an inductor and a resistor. Alternatively, a parallel resonance circuit of an inductor and a capacitor exhibiting high impedance only at a specific frequency can be used. The varistor 53 is for protecting the inductor 55 from excessive voltage, and a semiconductor varistor, a ceramic varistor, or the like can be used. As for the capacitor 51, the case 7 'is connected to the terminal 35 with a low impedance with respect to the frequency of the inductive ripple, and the property of a capacitor that cuts off direct current is used. It is determined appropriately according to the frequency and the constant. Although the first embodiment and the second embodiment described above have the same function in reducing the output ripple, when comparing the two, the case is grounded in the first embodiment. In the second embodiment, the case is at a slightly floating potential, whereas it must be provided internally, but there is no need to provide a shield case inside. A convenient configuration may be selected by comparing the advantages and disadvantages of the two. The type of insulating medium in the high voltage generating section is not particularly limited, and is not limited to silicone rubber, but may be insulating oil, insulating gas, or a thermoplastic resin such as epoxy resin. In particular, when epoxy resin is used, a conductive case or metal foil can be used instead of the shield case or the case. In that case, the high-voltage generator can be made smaller and lighter.

As described above, the present invention has the above-described features, and therefore, in the traveling wave tube power supply device, the output ripple can be reduced without adding a capacitor to the output. Therefore, the stored energy between the output terminals is small,
The rush current value into the traveling wave tube is reduced, which is useful for preventing deterioration of the tube.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a traveling wave tube power supply device according to the present invention.

FIG. 2 shows a traveling wave tube power supply device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... High frequency inverter 3 ... Transformer 5 ... Shield case 6 ... High voltage generation part 7 ... Grounding case 7 '... Case 8 ... Power supply device for traveling wave tube 11, 13, 15 ... Floating capacitance 17, 19, 21, 23 ... Diode 18 ... Bridge rectifier circuit 20 ... Voltage doubler rectifier circuit 25,27,33 ... Capacitor 29,31 ... Diode 35
... Cathode output terminal 37 ... Collector output terminal 39 ... Helix output terminal 41
… Ground 43… travelling wave tube 44… filament 45… cathode 47… helix 49… collector 51… condenser
53… varistor 55… inductor

Claims (2)

(57) [Claims] 1. A traveling wave tube power supply device comprising: a high frequency inverter; an insulating transformer and a rectifier circuit driven by the high frequency inverter; and a high voltage generator for supplying power to a helical electrode and a collector electrode of the traveling wave tube. Wherein the high-voltage generating section is covered with a first conductor via an insulating medium, and the first conductor is connected to a cathode potential of the traveling wave tube, and the first conductor is connected to the first conductor. And a grounding connection through a second conductor via an insulator. 2. A traveling wave tube power supply device comprising: a high frequency inverter; an insulating transformer and a rectifier circuit driven by the high frequency inverter; and a high voltage generator for supplying power to a helical electrode and a collector electrode of the traveling wave tube. Wherein the high-voltage generator is covered with a conductor via an insulating medium, and the conductor is connected to ground via an impedance element and connected to the cathode of the traveling wave tube via a capacitor. Characteristic power supply for traveling wave tube.