SU1496017A2 - Pulsed x-ray generator - Google Patents

Abstract

A pulse X-ray apparatus comprises a charging transformer (1), a high- voltage pulse transformer (8) and a positive current feedback transformer (15). Each of primary windings (17) of the transformer (15) is connected in series to a controlled transistor switch (5, 5', 5'') and to one of primary windings (2) of the transformer (1). A secondary winding (16) of the transformer (15) is connected to an input (19) of a pulse adder-distributor (20) electrically connected to a master oscillator (22) and the switches (5, 5', 5''). A secondary winding (3) of the transformer (1) is connected, via a rectifier (7), to a charging capacitor (6) electrically connected, via a discharger (10), to a primary winding (9) of the transformer (8) having its secondary winding (13) connected, via a peaker discharger (11), to an X-ray tube (12). <IMAGE>

Description

one

(61) 1441488

(21) 4022406 / 24-25

(22) 02.18.86.

(46) 07.23.89, Bull. 27

(71) Leningrad Scientific and Production Association Burevestnik

(72) S. B. Krasilnikov, L. N. Lozovoi, S. N. Markov and E. I. Sindalovsky

(53) 621.386 (088.8)

(56) USSR Author's Certificate No. 1441488, cl. H 05 G 1/24, 1985.

(54) PULSE X-RAY GENERATOR

(57) The invention relates to pulsed X-ray diffraction and can be widely used in pulsed X-ray flaw detection, pulsed X-ray diffraction of fast processes and in medicine. The purpose of the shadow is to invent the KCD. The pulsed x-ray generator contains a charging transformer 4 with N primary windings, each of which includes a controllable transistor switch 3; transformer 8 positive current feedback with N primary and one secondary windings; adder-distributor 2 pulses connected to master oscillator 1; a storage capacitor 13, a high-voltage pulse transformer 16; sharpener 18 and x-ray tube 19. Due to the introduction of diode 11 and the illuminated winding 10 of the transformer 8 positive current feedback, as well as the presence of the third input at the distributor 2, the generator efficiency is increased. 2 Il.

four

SO O5

14)

31496

The invention relates to X-ray technology, namely to pulsed X-ray generators intended for non-destructive testing of materials by X-ray, pulsed X-ray of fast processes and X-ray of various organs of patients under unsteady conditions, and is an improvement to the invention in accordance with the author. K 1441488.

The purpose of the invention is to increase

Efficiency

FIG. 1 shows a diagram of a pulsed x-ray generator; in fig. 2 - embodiment of the adder-distributor of pulses on passive diode-resistor elements ...

The pulsed x-ray generator contains a master oscillator 1, operating through a two-pulse adder-distributor, the operation of transistor switches 3, the charging transformer 4, N of the primary windings 5 of which are galvanically separated from each other and wound so that the magnetic fluxes caused by the switched current, the secondary windings 6, N of the primary windings .5 of the charge transformer .4 are connected in series with the N primary windings 7 of the transformer 8 of the positive current feedback, the secondary winding 9 of which It is connected to the second input of the distribution adder 2 pulses. The bottom of the winding 10 of the transformer 8 positive current feedback is connected in series and in accordance with one secondary winding 5 of the charging transformer 4, with one end connected to the low-potential end of the secondary winding 6 of the charging transformer 4 and the anode of the diode 11, and the other - to the third input of the adder-distributor 2 pulses. The cathode of diode 11 is connected to the common point of the primary windings 5 of the charging transformer 4. The high potential end of the secondary winding 6 of the charging transformer A is connected to rectifier 12, which is connected to the storage capacitor 13 and through the voltage source 14 to the primary winding 15 of the high voltage pulse transformer 16, in the secondary winding 17 of which are connected in series the peaking discharger 18 and the X-ray tube 19.

The totalizer distributor 2 (FIG. 2) contains a current feedback diode 20, a communication diode 21 with a master oscillator 1, a overvoltage diode 22, output resistors 23.1-23.N, and has N outputs 24.1-24. N. Input b of distribution distributor 2 is connected to the secondary winding 10 of transformer 8 positive current feedback, input a to the secondary winding 9 of this transformer 8, input to the output of the master oscillator 1, and outputs 24.1 t 24.N to the inputs of transistor switches 3. The inputs of quince through diodes 20 and 21 are connected to the input bis outputs 24.1-24.N. Through resistors 23.1-23.N. The anode of the diode 20 is connected to the secondary winding 9 ,. transformer 8 positive current feedback, anode of diode 21 to output of master oscillator 1, and anode of diode to common wire. It is also possible to perform the distributor adder 2 pulses and on active elements, for example, integrated operational amplifiers, which allows extending its functionality

In addition, the ratio between the number of turns of each primary field 7 of the transformer 8 positive current feedback, the number of turns VJ of each primary winding 5 of the charging transformer 4 and the magnetic resistances I / cos and R / ie of these transformers 8 and 4 selected from condition W

ptos

W

T15T

M m 5T

The pulsed x-ray generator works as follows.

Tasks 1 generator 1 generates synchronization pulses with a constant frequency, which through a distributor adder 2 pulses, resistors 23.1-23.N and outputs 24.1-24.N simultaneously arrive at the control inputs (bases) of transistor switches 3. In this case the latter open and linearly increasing currents flow through their collector circuits along the circuit of the constant-current power source through N parallel branches, which triggers a pulse from the master oscillator 1.

As a result of the repetition of the described processes with a frequency determined by master oscillator 1, the voltage on the storage capacitor 13 gradually increases until the voltage level of the breakdown of the switching discharger 14 is reached, which connects the charging storage capacitor 13 to the primary winding 15 of the high-voltage pulse transformer 16. In the secondary winding 17 of this transformer 16, a high-voltage voltage pulse is generated, which is fed through the discharge sharpener 18 to the X-ray tube 19.

For the operation of a pulsed x-ray generator, it is necessary that most of the energy of the transformer 8 positive current feedback is transferred to the storage capacitor 13. The energy accumulated in the magnetic core of the transformer 8 positive current feedback is only gf

 mob

Noah's winding 10 of the transformer 8 positive current feedback; 1, - the maximum current of the secondary winding 6 of the charging transformer A.

However, the deideal characteristics of the elements of the electric circuit of a pulsed X-ray generator, the technological variation of the parameters of transformers, and so on, inevitably violate this condition. Since the IMOJO mgg condition leads to the deterioration of the X-ray pulsed X-ray generator, it is necessary to fulfill the following relationship:

   I M1T

In this case, the excess energy of the transformer 8 is positive current feedback through the return diode 11

shields the dc power supply and ensures reliable operation of the generator with increased efficiency. Providing this condition the number of turns to the ard winding W

about

is defined as follows.

The magnetic motive forces (MDS) of transformers 4 and 8 at the time of locking the transistor 1. 1x keys 3 are equal to:

mc

ST

 I

MDSld - V „ds Scepa RAITOC where the number of turns of the primary winding of the charging transformer;

I co the maximum total current collectors controlled transistor switches 3}

mass induction saturation;

RMTOC magnetic resistance;

serch cross-sectional area of a positive current feedback transformer core.

The currents determined by these magnetomotive forces are: dp of the secondary winding 6 of the charge transformer - JTopa 4

, J ikwi

, t code w n

ът

for test winding 10 of transformer B positive current feedback

 cepj

W,

1 °

where W is the number of turns of the secondary winding of the charge transformer 4;

n, is the transformation ratio of the transformer 4;

Wgj, is the number of turns at the bottom; windings 10 of the transformer 8 positive current feedback.

I. .

From these relations and the above second inequality, we can obtain the ratio

W ..

mas ser mtos t -col

which determines the conditions for transferring the energy of the transformer magnet core 8 of the positive current feedback to the storage capacitor 13 / i.e. a condition in which a pulsed x-ray machine has the highest efficiency.

In addition, when current flows through the circuit containing the secondary winding 6 of the charging transformer 4, the charge winding 10 of the transformer 8 positive current feedback, the rectifier 12, the storage capacitor 13 and the distributor diode 22 2 pulses, on the bases of transistor switches 3 supported: | the locking potential equal to the voltage drop across the diode 22, which results)

the serial connection of one primary winding 5 of the charge transformer 4 and one primary winding 7 of the transformer 8 positive current feedback.

The secondary winding 6 of the charging transformer 4 and the bottom of the winding 10 of the transformer 8 of the positive current feedback are connected in series and connected to the full-wave rectifier 12 in such a phase that the electromotive voltage on their outputs at the moment of opening the keys 3 drive 12. As a result, the current in these windings 6 and 10 at this time does not flow through the primary windings 5 of the charging transformer

4 only the magnetizing current of the core of this transformer 4 flows. Such a mode is characterized by a large amount of inductance of the primary windings 5 of the transformer 4.

At the same time, the secondary winding 9 of the transformer 8 positive feedback Noy current connection is loaded on the low-ohm input to the adder-distributor 2 pulses, to the outputs 24.1-24.N. which are connected to the control inputs of the transistor keys 3. Therefore, the main part of the voltage of the DC power source in this series circuit is applied to the primary windings

5, the bottom of the transformer 4 and only a small part of it to the primary windings 7 of the transformer 8 positive current feedback, since the inductance and resistance given to the primary windings 7 of this transformer B are small. As a result, the currents in these parallel circuits are determined by the primary inductive nature of the resistance of the primary windings, 5 of the charging transformer 4 and linearly increasing. In this case, magnetic fluxes grow proportionally.

in the cores of both transformers 4 and 8, and when the magnitude of magnetic eduction in the core of the transformer 8 positive current feedback reaches the usins, the inductance of its tangency drops sharply and, accordingly, the emf in both the primary 7 and the secondary windings 9 leads to a sharp decrease in the voltage supplied through the input to the adder-distributor 2

pulses. This leads to a sharp decrease in the base currents of the transistor n:: keys 3, they go out of mode g saturation} w and begin to close. As a result, the current derivative of the primary windings 5 and 7 of transformers 4 and 8 becomes negative, and all the EMF in the windings of transformers 4

0 and 8 change their sign to OPTICAL.

In this mode, a reverse voltage is applied to the control inputs of the transistor switches 3: 5, which causes them to be forced

locking. Simultaneously, the EMF is in series with the secondary winding 6 of the charging transformer 4 and the secondary charging winding 10 of the Transformer

0 8 positive feedback by

The rectifier 12 opens the current, and the occurrence of a discontinuously linear current of these secondary windings charges the storage capacitor 13 to a higher potential. This current is created by the energy of the magnetic field accumulated in the magnetic conductor of the charge transformer 4 and the magnetic conductor of the transformer 8 pos.

0 current feedback.

For normal operation of the described scheme, it is necessary that the current created by the charge winding 10 of the tansformer 8 positive current feedback be higher than the current generated by the secondary winding 6 of the charging transformer 4. At the same time, a small part of the magnetic core energy the transformer 8 is recuperated to the DC power source through diode 11. Thus, at the first (The stage of the transfer of anergy accumulated in the magnetic conductor of transformers 4 and 8, the current flows not only through the series-connected winding These transformers, but also through diode 11 and source + E. Because the time of this circuit is constant:

0 is small, then excess energy is quickly recovered to the DC source, and diode 11 is lost. Further, the energy of the cores of the transformers 4 and 8 is transmitted only

5 to a storage capacitor 13 / Upon completion of these processes, the transformers 4 and 8 and the transistor switches 3 are simultaneously de-energized, and are in standby mode until the

five

to a significant decrease in leakage currents of transistor switches 3 and an additional increase in efficiency

Claims (2)

Invention Formula Pulsed X-ray generator for a BT. St. N: 1441488, about the fact that, in order to improve the efficiency, the diode and the dose of the winding of the transformer of positive current feedback are introduced, one end of which is connected to the low-potential end of the secondary winding the one transformer and the anode of the diode, the cathode of which is connected to the common, point of the primary windings of the charging transformerJ, the distributor adder is equipped with a third input connected to the other end R windings of the transformer of the feedback in the feedback, the total number of turns of the a. and the winding is selected from  us serch mtos  5G saturation induction; reluctance; the area of the core of the transformer core positive current feedback; maximum total collector current of transistor switches; transformation ratio of charge transformer. 2.Af 25.1 phi.2