CN203775032U - High-voltage power supply for X-ray generator - Google Patents

Abstract

A high-voltage power supply for an X-ray generator comprises a 220V AC to 48V DC module, a 48V DC to high voltage control module, and a voltage doubler rectifier module which are all sequentially connected. Outputs of the 48V DC to high voltage control module and the voltage doubler rectifier module are connected with a cathode filament end and an anode target end. A chip of converting 48V DC to high voltage control uses a UC3526A chip. The high-voltage power supply for the X-ray generator is repeatedly applied in actual practices, and thus the quality and reliability are fully guaranteed.

Description

A kind of x ray generator high voltage source

Technical field

The utility model relates to a kind of power supply, especially the technical field of high-precision high voltage power supply.

Background technology

X ray has penetration power, and this penetration power is relevant with material density, and the material that density is large is many to the absorption of X ray, sees through few; The little person of density, absorbs less, sees through many.Therefore utilize difference to absorb this character, the different material of density can be made a distinction.Be widely used in medicine equipment and Industrial-Type non-destructive defect-detecting equipment, and calibrator, fluorescence analysis, contraband detecting etc. need the field of high stability, high-precision high voltage power supply.

X ray power supply in the past, adopts heavy low-frequency power more, adds voltage regulator, carries out multiplication of voltage, thereby reaches the object that produces high pressure, and this power supply is not only heavy, and at the bottom of efficiency, a lot of weak points of the large grade of volume.

Summary of the invention

The utility model object is, proposes the high voltage source that a kind of x ray generator (X-ray tube) is used, and has overvoltage and the short-circuit protection function of Switching Power Supply.And be that modular structure is for the power source special to X-ray tube power supply.

Technical solutions of the utility model, a kind of x ray generator high voltage source, comprise that 220VAC is transformed into 48VDC module and is transformed into high voltage control and voltage doubling rectifier module and is connected successively with 48VDC, the output that 48VDC is transformed into high voltage control and voltage doubling rectifier module is connected to cathode filament and plate target two ends.Separately be provided with filament supply, wherein filament supply is used to the filament heating of X-ray tube.By the high voltage electric field providing, make electronics active on filament add flow speed and direction plate target, form high-speed electron flow and drive X-ray tube work.Separately be provided with filament supply, wherein filament supply connects the filament of X-ray tube.

Further, be provided with outer casing of power supply, outer casing of power supply is provided with the cooling and two kinds of radiator structures of fan air blast cooling of nature.Naturally cooling and two kinds of radiating modes of air blast cooling, adapt to the severe operational environment of high temperature.Because the negative polarity high voltage source of exporting is directly connected with X-ray tube negative electrode, therefore X-ray tube plus earth is very beneficial for radiating treatment, makes X-ray tube cathode voltage and anode current all obtain high stability.

Further, 48VDC is transformed into the chip employing UC3526A chip of high voltage control.

Further, voltage doubling rectifier module adopts switch controlled to recommend high frequency transformer, and high frequency transformer output connects full-wave rectification C filter and connects output loading again.

The beneficial effects of the utility model are: power supply conversion efficiency is high, and power supply is stable, and volume is little, lightweight; By interface connector and built-in-potential device, realize this locality of pipe high pressure and tube current and Long-distance Control, monitoring function; The module of simultaneously selecting has overvoltage and short-circuit protection function.That the power source special to X-ray tube power supply is produced in design.The utility model adopts existing advanced person's switch power module technology.Overcome the shortcoming of low-frequency power.Reduce volume, promoted efficiency.Increased reliability.Work that can be steady in a long-term, for ensureing working smoothly of complete equipment.220VAC converts 48VDC to, and 48VDC is transformed into high voltage control part and voltage multiplying rectifier part, all adopts modular construction, the technique of producing and installing is all easier, the module of voltage multiplying rectifier part, mounting means, adopt the structure of stack to install, reduce space, layout is bright and clear.X-ray source with adopt 10 core aviation plugs being connected of power supply, it is all own well-designed that the structure of plug is placed.The panel layout of power supply can adopt unique design.

Accompanying drawing explanation

Fig. 1 is the circuit theory diagrams of the main circuit of the utility model high voltage source;

Fig. 2 is circuit working oscillogram of the present utility model;

Fig. 3 is the chip that circuit of the present utility model is used;

Fig. 4 is x ray generator entire block diagram of the present utility model.

Embodiment

Below in conjunction with drawings and Examples, the utility model is described further.

Voltage doubling rectifier module to the operating voltage (as 140KV) of X-ray tube as shown in Figure 1, in Fig. 1, Ui is input dc power potential source, C1 is filter capacitor, S1, S2 are switching tube, W1, W2 are for recommending high frequency transformer, and D1, D2 are full-wave rectification diode, and L, C2 form LC filter, RL is output loading, and Uo is output voltage.Respectively with two, the two ends switching tube of transformer primary side coil W1 is connected, and centre cap is connected with power cathode; The two ends of secondary coil W2 are connected on respectively the anode of full-wave rectification diode, and its centre cap is output voltage negative pole.Rectification is load supplying after by L, C2 filtering.

Its course of work is as follows: when S1 conducting, when S2 turn-offs, rectifier diode D1 bears malleation in on-state, and D2 oppositely ends.Rectification is load supplying after by L, C2 filtering; When S1 turn-offs, during S2 conducting, rectifier diode D2 bears malleation in on-state, and D1 oppositely ends, and rectification is load supplying after by L, C2 filtering; When S1, S2 all turn-off, D1, D2, in on-state, respectively share half electric current.Its work wave is as shown in Fig. 2 .2.

Because when S1 conducting, when S2 turn-offs, primary coil turning part voltage is supply voltage, i.e. UN1=Ui, and the upper and lower two-part induced electromotive force of W1 centre cap equates, i.e. UN1 '=UN1=Ui.And S2 both end voltage is supply voltage and the induced electromotive force sum below primary coil centre cap, i.e. US2=Ui+UN1 '.So, the twice that the crest voltage bearing when S1, S2 off-state is supply voltage, i.e. US=2Ui.

If S1, S2 conducting simultaneously, is equivalent to the short circuit of transformer first side winding, therefore to avoid this kind of situation to occur, the duty ratio of each switching tube must not be greater than 50%, and certain Dead Time is set.

When switching tube S1 conducting, when S2 turn-offs, it is upper that input voltage Ui is added in primary coil N1, and produce induced electromotive force on secondary coil N2, makes diode D1 bear malleation and conducting is load supplying after LC filtering, and now diode D2 ends because bearing back-pressure.Output voltage U o is now

$U_o=\frac{N_2}{N_1}\frac{t_{\mathrm{on}}}{T}{U}_i---(2-1)$

When switching tube S2 conducting, when S1 turn-offs, input voltage Ui is added on primary coil N1 ', and at the upper induced electromotive force that produces of secondary coil N2 ', make diode D2 bear malleation and conducting is load supplying after LC filtering, now diode D1 ends because bearing back-pressure.Output voltage U now _ofor

$U_o=\frac{{N_2}^{,}}{{N_1}^{,}}\frac{t_{\mathrm{on}}}{T}{U}_i---(2-2)$

Again because N1=N1 ', N2=N2 ', total output voltage is output voltage sum under two on off states, so have

$U_o=\frac{N_2}{N_1}\frac{t_{\mathrm{on}}}{T}2U_i---(2-3)$

Be more than the continuous situation of output current, when output current is interrupted, output voltage U o is the calculated value higher than formula 2-3, and with the reducing and raise of load, and is under zero limiting case in load,

$U_o=\frac{N_2}{N_1}{U}_i.$

Input voltage is that the Switching Power Supply main circuit of low-voltage generally adopts push-pull topology structure, because this structure can make the two-way magnetization of transformer, high efficiency is utilized iron core, is conducive to reduce volume and the weight of transformer; Simultaneous Switching pipe frequency is 1/2 of output PWM ripple frequency, and the pulsation that is conducive to reduce to export DC bus-bar voltage reduces the size of filter inductance, improves the precision of voltage regulation; Transformer primary side circuit structure is simple, is conducive to improve the utilance of input voltage.

The utility model 48VDC is transformed into the control chip of high pressure, adopts UC3526A chip to occur and control chip as PWM.UC3526A is the PWM generator that TIX produces at first, is widely used among Switching Power Supply class power electronic equipment.What UC3526A inside adopted is that a kind of frequency is fixed, the integrated circuit that pulse duration can be modulated, and the control of Switching Power Supply, modulation and protective circuit are all in it, and in single-ended forward type, semibridge system, full-bridge type and push-pull type Switching Power Supply, are used widely.Its inner integrated whole pulse width modulation circuits; Sheet is built-in with linear saw-tooth wave oscillator, and the outside electric capacity of a resistance that only needs forms concussion element; Built-in error amplifier; 5V reference voltage source is placed in sheet; Dead Time is adjustable; The power transistor that has 200mA driving force is placed in sheet; Have two kinds of way of outputs of push-and-pull.Its simple internal frame diagram as shown in Figure 3.

220V AC conversion 48VDC module adopts existing reference power supply module, typically adopts model MW/NES-150-48; But 48V DC is transformed into being described by the present embodiment of high pressure voltage doubling rectifier module.

The main circuit of UC3526A chip: 1. oscillating circuit: oscillating circuit is comprised of RT, the CT of 9,10 bipods.The value of RT and CT, is the operating frequency that determines this chip, F=1/1.1*CT*RT; 2. pulse-width modulation circuit: 1,2 bipods of chip are the positive inverting inputs of voltage comparator circuit, adjusts the voltage ratio between 1,2 bipods, can be that the duty ratio of PWM output 13,16 bipod pulses changes between 0 to 49%.When the voltage difference △ U12 of 1,2 bipods is 0MV.The duty ratio of its output waveform is 25%.There is linear relationship in the size of the voltage difference △ U12 of the size of the duty ratio of the output waveform of UC3526 and 1,2 bipods.So can recently adjust by changing the duty of output waveform the height of output voltage; 3. soft starting circuit: soft starting circuit is to be decided by the electric capacity of receiving 4 pin, maximum delay is at the soft-start time of 80 milliseconds; 4. current foldback circuit, overcurrent protection is controlled at 67 bipods, when the current potential between two pin is during in 100MV left and right, circuit operation, thus block PWM output.

Electric property: input: AC220 ± 10%; Output: the multiple maximal pressure output such as 80KV, 140KV and 160KV is optional, and 0V is adjustable to ceiling voltage.

Voltage control:

Power supply is inner: the multiturn potentiometer that power supply carries can be arranged on output voltage 0V between ceiling voltage;

External remote control: outside 0 to 10V control signal can will be exported the output voltage of turning up full blast from 0V.

Tube current is controlled;

Power supply is inner: the multiturn potentiometer that power supply carries can be arranged on 0A to maximum current by electron beam current;

External remote control: outside 0 to 10V control signal can be arranged on 0A to maximum current by electron beam current;

Direct current filament supply: output current is that 4A is adjustable, voltage is 5.5V.

Voltage regulation:

Load relatively: 0.01% (unloaded to nominal load);

Relatively input: ± 0.01% (input voltage be changed to ± 10%).

Current regulation:

Load relatively: 0.01% (unloaded to nominal load);

Input relatively: ± 0.01% (input voltage changes ± 10%).

Ripple voltage: under the condition of output rated voltage, the peak-to-peak value of ripple voltage is maximum output voltage 0.1%.

Ambient temperature: during work 0 to+50 ℃; During storage-20 ℃ to+80 ℃.

Temperature coefficient: every degree Celsius 0.01%; Stability: start is less than 0.05% in every 8 hours after half an hour.

Electric current and voltage indication: 0 arrive+10V, under specified output condition, precision is 1%.

Connector:

Input and output connector: DB9, comprises and controls and display;

The Long-distance Control of output voltage and electric current: can utilize the 10V reference voltage of power supply inside to carry out Long-distance Control to output voltage and electric current by external potentiometer; Remote voltage electric current indication: DB9 pin binding post has comprised 0 to 10V voltage and current index signal, can external various numerals or pointer gauge.

Chip provides voltage multiplying rectifier and voltage sampling part.

Separately be provided with filament voltage power pack.RS232 interface, energy supply control module and x-ray source coupling part.Voltage multiplying rectifier and voltage sampling, adopt two superimposed to place, and reduced space.

The connection of power module part and x-ray source part, adopt 10 core aviation plugs, the output of plug is arranged on modular power source, be arranged on the lower left corner, the below of earth connection, the left side of upper next row LED, RS232 interface is installed on the right side of LED, I/O switch is installed in the upper right side of RS232 interface, and AC power supplies input socket is installed in lower right.The input of aviation plug, receives on the shell of x-ray source.

The above is only preferred implementation of the present utility model; be noted that for those skilled in the art; do not departing under the prerequisite of the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.

Claims (5)

1. an x ray generator high voltage source, it is characterized in that comprising that 220VAC is transformed into 48VDC module and is transformed into high voltage control and voltage doubling rectifier module and is connected successively with 48VDC, the output that 48VDC is transformed into high voltage control and voltage doubling rectifier module is connected to cathode filament and plate target two ends.

2. x ray generator high voltage source according to claim 1, is characterized in that being separately provided with filament supply, and wherein filament supply connects the filament of X-ray tube.

3. x ray generator high voltage source according to claim 1, is characterized in that being provided with outer casing of power supply, and outer casing of power supply is provided with the cooling and two kinds of radiator structures of fan air blast cooling of nature.

4. x ray generator high voltage source according to claim 1, is characterized in that 48VDC is transformed into the chip employing UC3526A chip of high voltage control.

5. x ray generator high voltage source according to claim 1, is characterized in that voltage doubling rectifier module adopts switch controlled to recommend high frequency transformer, and high frequency transformer output connects full-wave rectification C filter and connects output loading again.