JPS58141679A - High voltage generator - Google Patents

Abstract

PURPOSE:To reduce the ripple component of a voltage waveform of a high voltage generator by connecting a plurality of unit converters, operating them in the same frequency and dividing the phase, thereby displacing the phases and driving with each other. CONSTITUTION:A plurality of voltage resonance type converters 2 are connected in parallel between the output terminals of a power source 1. The converters 2 connected a condenser 4 between the input terminals 3a and 3b, and connects the collector of a switching element made of a transistor at the terminal 3a of anode side. The switching element 5 of the converter 2 is operated in ON or OFF at substantially constant frequency, the drive pulses inputted to the respective elements 5 are displaced in the prescribed phase, thereby superposing them from each other. In this manner, continuous output wave can be obtained even without using a smoothing circuit of particularly large electrostatic capacity in the secondary side circuit of the converter 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a high voltage generator, such as an X-ray generator, which supplies Iζ power.

A special feature of the high-voltage generator for X-
Severe frequency of disconnection, high pressure generator and load (X-ray tube)
One example of this is the need to connect using long cables due to the distance between the computer and the computer.

Conventional high-voltage generators for X-rays use a transformer with a silicon steel plate as the magnetic core to generate a p-ac current of several hundred H2 from the commercial frequency.
The voltage is increased by kv~400kV J. Since this high-voltage cable and step-up transformer have the frequency characteristics of a low-pass filter, the economical operating frequency of a converter that can be used in a high-voltage generator for X-rays is kept below several hundred 8B.

[Problems with conventional technology]

According to such a device, if power is required to be turned on and off more than 20 times per second, a fast voltage rise characteristic is naturally required, and an operating frequency of several hundred Hz will not be able to keep up with this. .

[Purpose of the invention] This invention was made based on the above circumstances.

It is possible to obtain a continuous output voltage waveform without the need for a special capacitance smoothing circuit, and improve the coordination of the power transmission system. The purpose of the present invention is to provide a high-pressure generator capable of stably transmitting data.

[Summary of the invention]

In this invention, a step-up transformer of a voltage resonant switch circuit is wound around the body, and each winding is coupled with a diode to generate a high voltage. A plurality of unit converters are connected in parallel, in series or in series-parallel. According to the present invention, the output pulses of a plurality of converters can be operated at approximately the same frequency and driven by dividing one phase and shifting the phase from each other. To drive by shifting - from this.

Since the ripple component of the voltage waveform can be reduced,
It becomes less susceptible to the influence of transmission cables having low-pass filter characteristics. Further, since a continuous output voltage waveform can be obtained without using a smoothing circuit with a particularly large capacitance in the secondary circuit, the coordination of the power transmission system can be significantly improved.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to one drawing.

In Figure 1, 1 is an input power supply, and multiple voltage resonant converters (unit converters) are connected between the output terminals of this power supply 1.
Connect 2 in parallel. 343b is an input terminal of this converter 2.

This voltage resonance type converter 2 has a capacitor 4 connected between input terminals 3a and 3b, and a collector of a switching element 5 made of a transistor is connected to the anode side terminal 3a. A damper diode 6 is connected between the collector and emitter of this switch element 5 with the polarity shown, and the input terminal 7 of the pulse train P, , P, , P is connected to the base. Further, the primary side of the transformer 8 is connected between the emitter of the switching element 5 and the terminal 3b, and the negative side lζ resonant capacitor 9 and the resonant coil lO are respectively connected in parallel. The transformer 8 has a primary winding 8b wound around a magnetic core of 8 m and a plurality of secondary windings 8C.
It is composed of A plurality of secondary windings 8C are connected in series via diodes 11 having the same polarity as shown in the figure. A dummy resistor 12 is connected in parallel to the output terminal of this secondary side to constitute a voltage resonant converter 2.

Further, the secondary sides of each voltage resonant converter 2 are connected in parallel and connected to the X-ray tube 14 via a power transmission cable.

Next, the operation of this embodiment will be explained.

If the switching element 5 of each voltage resonant converter 2 is turned on and off at a substantially constant frequency, α8. ...
Shift by α1 so that they overlap with each other. Furthermore, by dividing the secondary winding 8c of the transformer 8 into eight pieces, the primary winding 8b can be adjusted depending on the operating frequency of the voltage resonant converter 2.
and the excitation inductance of the transformer 8. Set the impedance to a value that is sufficiently larger than the resonance inductance.

Next, since each voltage resonance type converter has the same configuration, the operation of the first stage voltage resonance type converter 2 will be explained, and the operation explanation of the subsequent stage voltage resonance type converter 2 will be omitted.

When the switch element 5 is driven by the pulse P1, the on/off operation is reversed. At this time, when the switch element 5 is turned on, a current flows from the power source 1 to the resonant coil 10, and the on operation of the switch element 5 continues for a period of time Ton, as shown in FIG. 3(a). The sickle 1. Switch element 5
When turned off, the current flowing through the resonant coil 10 has inertia.

Charging of the resonant capacitor 9 begins. As a result, the terminal voltage vc of the resonant capacitor 9 changes in a resonant arc as shown in FIG. It is returned to the power supply l via. If the polarity of the primary and secondary sides of Metamorphosis-8 is selected in advance as shown in Figure 1, the dummy resistor 1 provided in the secondary side circuit
A voltage obtained by multiplying the winding ratio of the positive part shown in FIG. 3 (1b) by the number of divisions N is applied to both ends of 2. Thereafter, when the damper' wax flow of τd shown in FIG. 3 (C1) finishes flowing, the next cycle starts.

The voltage waveform applied to the transformer 8 has an area S on the negative side and an area 8! on the positive side, as shown in FIG. 3(b). Paying attention to the fact that they are the same, the positive pulse width shown in Figure 3 (b) is usually narrower than the half period T/2, so in order to make the output pulses of the voltage resonant converter 2 overlap each other, A voltage resonant comparator A of at least 3 or more is required. In order to reduce the ripple component of this superimposed pressure waveform, it is desirable to insert many output waveforms at equal intervals during one cycle, as shown in FIG.

Therefore, according to such a configuration, by dividing the phase of each voltage resonant converter 2 into equal parts and connecting them in parallel, a particularly large amount of static electricity can be applied to the secondary circuit of the voltage resonant converter 2. Since continuous output waves can be obtained without using a floor circuit, the connectivity of the power transmission system can be significantly improved. Further, by increasing the number of voltage resonant converters 2, it is possible to easily increase the output power.

Furthermore, by dividing the phases of each converter into equal parts and shifting them from each other so that the output waveforms overlap each other when each voltage resonant converter is operated at approximately the same frequency, the operating frequency of converter 2 is lower than the conventional one. Figure 4 shows the AC component that is affected by the low-pulse filter characteristics even when a power transmission cable is connected between the output end and a load such as an X-ray tube. Since it can be made as small as possible, the influence of power transmission can be improved.

[Other embodiments of the invention]

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the gist.

In the above embodiment, a plurality of converters are connected in parallel, but the present invention is not limited to this, and can also be implemented by connecting them in series or series-parallel, for example.

In the above embodiment, the phases of the plurality of converters are divided into equal parts and shifted from each other by one division.

Although a portion of each output wave is superimposed, the present invention includes a case where the above-mentioned phases are not equally divided or a case where a portion of the output wave is not completely overlapped.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. Fig. 2 is a time chart for explaining the driving of the converter of the same embodiment, Fig. 3 is a waveform chart for explaining the operation of the converter of the same embodiment, and Fig. 4 is a waveform diagram for explaining the operation of the converter of the same embodiment. It is an output waveform diagram of an example. 1... Input power supply 2... Narita resonant converter 3a, 3b... Input terminal 4... Capacitor 5
...Switch element 5C...Collector terminal 5m...
・Emitter terminal 5s...base terminal, 's...damper diode 7...input terminal 8...transformer ・8a...magnetic core 8b...-next winding 8C
...Secondary winding 9...Resonance capacitor 10...Resonance coil 11...Diode 12...Dummy resistors 13a, 13b...Output terminal 14...X-ray tube Figure 1, Figure 2 Figure 11! Figure 3

Claims (7)

[Claims] (1) A plurality of unit converters are connected in which the secondary side of the step-up transformer of the voltage resonant switch circuit is opened, and each winding is connected in series in the same polarity direction via a diode. A high-pressure generator characterized by operating at approximately the same frequency and driving the two by dividing the phases and shifting them from each other. (2) The high voltage generator according to claim 1, wherein a plurality of unit converters are connected in parallel. (3) The high-pressure generating device for iron according to claim 1, characterized in that a several unit converters are connected in series. (4) The high voltage generator according to claim 1, wherein the plurality of unit converters are connected in series and in parallel. (5) The high-voltage generator as set forth in any one of claims 1 to 4, wherein the driving phase of each of the plurality of unit converters is equally divided. (6) The high-voltage generator according to any one of claims 1 to 5, wherein the plurality of unit converters are driven with phases shifted so that their output waves overlap each other. (7) The 414th place converter is special in that it uses flyback pulses for power transmission pulses! /f
High pressure generation equipment as described in item 1 of the scope of the claim. [8] The high voltage generator according to claim 1, wherein the m1 converter uses forward pulses as pulses for power transmission.