阅读说明：本技术 一种小型电子加速器用励磁电源装置及其控制方法 (Excitation power supply device for small electronic accelerator and control method thereof ) 是由 刘琦 王仁波 王海涛 李金海 陈锐 杨志强 于 2021-07-12 设计创作，主要内容包括：本发明公开了一种小型电子加速器用励磁电源装置及其控制方法,主要涉及电子加速器领域；包括三相滤波器、全波整流器、LC滤波器、直流高压电源、电容组C、主励磁线圈L、IGBT1、IGBT1驱动器、IGBT2、IGBT2驱动器、IGBT3、IGBT3驱动器、续流二极管1、续流二极管2；本发明根据LC桥式振荡原理,由外部同步信号控制主励磁线圈电流的幅度大小和重复频率,从而产生强度变化的磁场,用于加速和约束电子,产生X射线,本装置体积小,重量轻,能够很好的适用于小型电子加速器。(The invention discloses an excitation power supply device for a small-sized electronic accelerator and a control method thereof, and mainly relates to the field of electronic accelerators; the device comprises a three-phase filter, a full-wave rectifier, an LC filter, a direct-current high-voltage power supply, a capacitor bank C, a main excitation coil L, IGBT1, an IGBT1 driver, an IGBT2, an IGBT2 driver, an IGBT3, an IGBT3 driver, a freewheeling diode 1 and a freewheeling diode 2; according to the LC bridge type oscillation principle, the amplitude and the repetition frequency of the current of the main magnet exciting coil are controlled by an external synchronous signal, so that a magnetic field with variable strength is generated and is used for accelerating and restraining electrons and generating X rays.)

1. An excitation power supply device for a small-sized electronic accelerator, characterized in that: the device comprises a three-phase filter, a full-wave rectifier, an LC filter, a direct-current high-voltage power supply, a capacitor bank C, a main excitation coil L, IGBT1, an IGBT1 driver, an IGBT2, an IGBT2 driver, an IGBT3, an IGBT3 driver, a freewheeling diode 1 and a freewheeling diode 2;

the input end of the three-phase filter is connected with three-phase alternating current;

the output end of the three-phase filter is connected with the input end of the full-wave rectifier;

the output end of the full-wave rectifier is connected with the input end of the LC filter;

the input end of the direct-current high-voltage power supply is simultaneously connected with one phase of three-phase alternating current and the output end of the LC filter;

the output end of the direct-current high-voltage power supply, the output end of the IGBT2 and the output end of the fly-wheel diode 2 are connected with the input end of the capacitor bank C;

the output end of the capacitor bank C is connected with the input end of the freewheeling diode 1 and the input end of the IGBT1 at the same time;

the output end of the IGBT1, the output end of the IGBT3 and the output end of the freewheeling diode 1 are connected with the input end of the main excitation coil L;

the output end of the main excitation coil L is simultaneously connected with the input end of the IGBT2 and the input end of the freewheeling diode 2;

the input end of the IGBT1 driver and the input end of the IGBT2 driver are both connected with a control signal 1;

the output end of the IGBT1 driver is connected with the input end of an IGBT 1;

the output end of the IGBT2 driver is connected with the input end of an IGBT 2;

the input end of the IGBT3 driver is connected with a control signal 2;

and the output end of the IGBT3 driver and the output end of the LC filter are connected with the input end of the IGBT 3.

2. A control method of an excitation power supply device for a small electronic accelerator is characterized by comprising the following steps:

s1, monitoring the synchronous control signal 1 in real time by the IGBT1 driver and the IGBT2 driver, and entering the step S2 when the monitoring control signal 1 is at a high level;

s2, the IGBT1 driver turns on the IGBT1, the IGBT2 driver turns on the IGBT2, the energy of the capacitor bank C flows to the main excitation coil L through the IGBT1 and returns to the capacitor bank C through the IGBT2, the current of the main excitation coil starts to continuously increase, the magnetic field intensity excited by the coil also continuously increases, and the step S3 is carried out;

s3, the IGBT1 driver and the IGBT2 driver monitor the low level of the control signal 1 in real time, when the control signal 1 is monitored to be the high level, the step is kept at S3, and when the control signal 1 is monitored to be the low level, the step is started to be S3;

s4, the IGBT1 driver turns off the IGBT1, the IGBT2 driver turns off the IGBT2, the main field coil L starts freewheeling, the coil current starts decreasing, and the process advances to step S5;

s5, the IGBT3 driver monitors the synchronous control signal 2 in real time, and when the control signal 2 is at a high level, the step S6 is carried out; when the control signal 2 is low level, it remains at step S5;

s6, the IGBT3 driver turns on the IGBT3, the LC filter supplies current to the main excitation coil L, and the process advances to step S7;

s7, the IGBT3 driver monitors the synchronous control signal 2 in real time, when the control signal 2 is at a low level, the step S8 is carried out, and when the control signal 2 is at a high level, the step S7 is kept;

s8, the IGBT3 driver turns off the IGBT3, the main coil current is reduced to 0, an LC oscillation period is completed, and the process advances to step S1.

Technical Field

The invention relates to the field of electronic accelerators, in particular to an excitation power supply device for a small-sized electronic accelerator and a control method thereof.

Background

At present, the energy of the X-ray generated by the electron accelerator is much higher than that generated by a common tube voltage type X-ray tube, so that the X-ray generated by the electron accelerator can penetrate an object with larger thickness. Because the electron accelerator can generate high-energy X rays, the electron accelerator is widely applied to nondestructive testing, customs container security inspection systems, industrial X-ray imaging detection devices and medical cancer treatment, and the small-sized electron induction accelerator has better advantages than other types of electron accelerators in the aspects of volume size, simple operation, low cost and the like.

For an electron accelerator, the volume and the weight of an excitation power supply account for two thirds of the whole electron accelerator, so that the electron accelerator is mainly miniaturized and lightened, and the problem of how to reduce the volume and the weight of the excitation power supply is mainly solved. The early main excitation power supply adopts an alternating current excitation power supply, a transformer is used for boosting, 220V alternating current is boosted to a certain value, then the alternating current is directly loaded on an excitation coil to generate 50Hz variable current, the power supply needs huge transformer windings and a large amount of compensation capacitors, so that the power supply device is huge in size, the current of the main excitation coil is 50Hz, the frequency of generated X-rays is also 50Hz, and the variable control cannot be carried out according to requirements.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides an excitation power supply device for a small-sized electronic accelerator and a control method thereof.

In order to achieve the purpose, the invention is realized by the following technical scheme:

an excitation power supply device for a small-sized electronic accelerator comprises a three-phase filter, a full-wave rectifier, an LC filter, a direct-current high-voltage power supply, a capacitor bank C, a main excitation coil L, IGBT1, an IGBT1 driver, an IGBT2, an IGBT2 driver, an IGBT3, an IGBT3 driver, a freewheeling diode 1 and a freewheeling diode 2;

the input end of the three-phase filter is connected with three-phase alternating current;

the output end of the three-phase filter is connected with the input end of the full-wave rectifier;

the output end of the full-wave rectifier is connected with the input end of the LC filter;

the input end of the direct-current high-voltage power supply is simultaneously connected with one phase of three-phase alternating current and the output end of the LC filter;

the output end of the direct-current high-voltage power supply, the output end of the IGBT2 and the output end of the fly-wheel diode 2 are connected with the input end of the capacitor bank C;

the output end of the capacitor bank C is connected with the input end of the freewheeling diode 1 and the input end of the IGBT1 at the same time;

the output end of the IGBT1, the output end of the IGBT3 and the output end of the freewheeling diode 1 are connected with the input end of the main excitation coil L;

the output end of the main excitation coil L is simultaneously connected with the input end of the IGBT2 and the input end of the freewheeling diode 2;

the input end of the IGBT1 driver and the input end of the IGBT2 driver are both connected with a control signal 1;

the output end of the IGBT1 driver is connected with the input end of an IGBT 1;

the output end of the IGBT2 driver is connected with the input end of an IGBT 2;

the input end of the IGBT3 driver is connected with a control signal 2;

and the output end of the IGBT3 driver and the output end of the LC filter are connected with the input end of the IGBT 3.

A control method of an excitation power supply device for a small electronic accelerator comprises the following steps:

s1, monitoring the synchronous control signal 1 in real time by the IGBT1 driver and the IGBT2 driver, and entering the step S2 when the monitoring control signal 1 is at a high level;

s2, the IGBT1 driver turns on the IGBT1, the IGBT2 driver turns on the IGBT2, the energy of the capacitor bank C flows to the main excitation coil L through the IGBT1 and returns to the capacitor bank C through the IGBT2, the current of the main excitation coil starts to continuously increase, the magnetic field intensity excited by the coil also continuously increases, and the step S3 is carried out;

s3, the IGBT1 driver and the IGBT2 driver monitor the low level of the control signal 1 in real time, when the control signal 1 is monitored to be the high level, the step is kept at S3, and when the control signal 1 is monitored to be the low level, the step is started to be S3;

s4, the IGBT1 driver turns off the IGBT1, the IGBT2 driver turns off the IGBT2, the main field coil L starts freewheeling, the coil current starts decreasing, and the process advances to step S5;

s5, the IGBT3 driver monitors the synchronous control signal 2 in real time, and when the control signal 2 is at a high level, the step S6 is carried out; when the control signal 2 is low level, it remains at step S5;

s6, the IGBT3 driver turns on the IGBT3, the LC filter supplies current to the main excitation coil L, and the process advances to step S7;

s7, the IGBT3 driver monitors the synchronous control signal 2 in real time, when the control signal 2 is at a low level, the step S8 is carried out, and when the control signal 2 is at a high level, the step S7 is kept;

s8, the IGBT3 driver turns off the IGBT3, the main coil current is reduced to 0, an LC oscillation period is completed, and the process advances to step S1.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the LC bridge type oscillation principle, the charging and discharging processes of the capacitor bank C and the main excitation coil L are controlled through a specific control method, stable and variable current is generated on the main excitation coil L, and a corresponding variable magnetic field is excited for accelerating and controlling electrons of the small-sized electron induction accelerator. The traditional excitation power supply device adopts an inverter circuit and a step-up transformer, the power supply structure is complex, the devices are heavy, the IGBT is used for controlling LC oscillation, stably-changing current is generated, the power supply structure is simplified, the size and the weight of the power supply are reduced, and the IGBT can be well suitable for a small-sized electronic induction accelerator, which is the greatest advantage of the invention;

2. the device has small volume, light weight and convenient control, can control the current amplitude and the repetition frequency of the main magnet exciting coil according to the repetition frequency and the duty ratio of a control signal, is very suitable for generating a control magnetic field in a small-sized electronic induction accelerator, and can control the energy and the dose rate of X rays generated by the accelerator by utilizing the device and the control method thereof.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention;

FIG. 2 is a control flow diagram of the present invention.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the present application.

The basic technical principle of the electron induction accelerator is that according to Maxwell's equation, a changing magnetic field can generate an induced vortex electric field, then electrons are accelerated by the induced vortex electric field and are constrained on a constant radius orbit, and when the electrons are accelerated to a certain energy by the electric field, electron beams strike a target to generate bremsstrahlung so as to generate X rays. The higher the energy at which the electrons are accelerated, the higher the energy of the X-rays produced. According to the basic principle, to accelerate electrons in a constant trajectory, a magnetic field of varying strength is generated. The exciting power supply of the electron induction accelerator can obtain a magnetic field with variable intensity inside the coil by controlling the current change of the main exciting coil, and electrons can be accelerated and restrained by the magnetic field. The excitation power supply device is used for providing current for the main excitation coil, and controlling the main excitation coil to generate stably-changed current according to a corresponding control method, so that a magnetic field with changed intensity can be obtained, and the functions of electronic acceleration and restraint are realized.

According to the LC bridge type oscillation principle, the capacitor bank is used for discharging to the main excitation coil to generate current, and the current change of the main excitation coil can be stably controlled only by simply controlling the oscillation process of LC and compensating the loss on the excitation coil, so that a changed magnetic field is generated.

Example 1: as shown in fig. 1, the excitation power supply device for a small-sized electronic accelerator according to the present invention includes a three-phase filter, a full-wave rectifier, an LC filter, a dc high-voltage power supply, a capacitor bank C, a main excitation coil L, IGBT1, an IGBT1 driver, an IGBT2, an IGBT2 driver, an IGBT3, an IGBT3 driver, a freewheeling diode 1, and a freewheeling diode 2;

the input end of the three-phase filter is connected with three-phase alternating current;

the output end of the three-phase filter is connected with the input end of the full-wave rectifier, and the full-wave rectifier rectifies the three-phase sine-wave voltage into half-wave voltage;

the output end of the full-wave rectifier is connected with the input end of the LC filter, and the half-wave voltage is further converted into direct-current voltage through the LC filter;

the input end of the direct-current high-voltage power supply is simultaneously connected with one phase of three-phase alternating current and the output end of the LC filter;

the output end of the direct-current high-voltage power supply, the output end of the IGBT2 and the output end of the fly-wheel diode 2 are connected with the input end of the capacitor bank C;

the output end of the capacitor bank C is connected with the input end of the freewheeling diode 1 and the input end of the IGBT1 at the same time;

the output end of the IGBT1, the output end of the IGBT3 and the output end of the freewheeling diode 1 are connected with the input end of the main excitation coil L;

the output end of the main excitation coil L is simultaneously connected with the input end of the IGBT2 and the input end of the freewheeling diode 2;

the input end of the IGBT1 driver and the input end of the IGBT2 driver are both connected with a control signal 1;

the output end of the IGBT1 driver is connected with the input end of an IGBT 1;

the output end of the IGBT2 driver is connected with the input end of an IGBT 2;

the input end of the IGBT3 driver is connected with a control signal 2;

and the output end of the IGBT3 driver and the output end of the LC filter are connected with the input end of the IGBT 3.

The three-phase alternating current is filtered by a three-phase filter, rectified by a full-wave rectifier and then filtered by an LC filter to obtain direct-current voltage. The direct-current voltage and the output voltage of the direct-current high-voltage power supply are superposed together and input into the main capacitor bank C, so that the main capacitor bank C reaches a certain voltage amplitude before the oscillation starts, and certain energy is stored.

The IGBT1 and the IGBT2 control the capacitor bank C to discharge to the main excitation coil L by the control signal 1, so that the current repetition frequency control of the main excitation coil is realized; the IGBT3 controls the main excitation coil L to perform loss energy compensation by the control signal 2; under the control of the control signal 1, the IBGT1 and the IGBT2 cooperate with the IGBT3 to form stable LC oscillation between the main excitation coil L and the capacitor bank C under the control of the control signal 2, so that the main excitation coil has a stably varying current, and a stably varying magnetic field is generated inside the coil, thereby satisfying the requirements of electronic acceleration and confinement.

According to LC bridge type oscillation principle, by amplitude and repetition frequency of outside synchronizing signal control main excitation coil electric current to produce the magnetic field of intensity change, be used for accelerating and restraint electron, produce X ray, this device is small, light in weight, and control is convenient, can be according to control signal's repetition frequency and duty cycle control main excitation coil electric current amplitude and repetition frequency, produces control magnetic field in the very suitable small-size electron induction accelerator, can be fine be applicable to small-size electron accelerator.

Example 2: as shown in fig. 2, the invention relates to a control method of an excitation power supply device for a small-sized electronic accelerator, which comprises the following steps:

s1, monitoring the synchronous control signal 1 in real time by the IGBT1 driver and the IGBT2 driver, and entering the step S2 when the monitoring control signal 1 is at a high level;

s2, the IGBT1 driver turns on the IGBT1, the IGBT2 driver turns on the IGBT2, the energy of the capacitor bank C flows to the main excitation coil L through the IGBT1 and returns to the capacitor bank C through the IGBT2, the current of the main excitation coil starts to continuously increase, the magnetic field intensity excited by the coil also continuously increases, and the step S3 is carried out;

s3, the IGBT1 driver and the IGBT2 driver monitor the low level of the control signal 1 in real time, when the control signal 1 is monitored to be the high level, the step is kept at S3, and when the control signal 1 is monitored to be the low level, the step is started to be S3;

s4, the IGBT1 driver turns off the IGBT1, the IGBT2 driver turns off the IGBT2, the main field coil L starts freewheeling, the coil current starts decreasing, and the process advances to step S5;

s5, the IGBT3 driver monitors the synchronous control signal 2 in real time, and when the control signal 2 is at a high level, the step S6 is carried out; when the control signal 2 is low level, it remains at step S5;

s6, the IGBT3 driver turns on the IGBT3, the LC filter supplies current to the main excitation coil L, and the process advances to step S7;

s7, the IGBT3 driver monitors the synchronous control signal 2 in real time, when the control signal 2 is at a low level, the step S8 is carried out, and when the control signal 2 is at a high level, the step S7 is kept;

s8, the IGBT3 driver turns off the IGBT3, the main coil current is reduced to 0, an LC oscillation period is completed, and the process advances to step S1.

The synchronous control signal 1 and the control signal 2 can be input from the outside, or can be generated by a CPU (such as an MCU, a DSP, an FPGA/CPLD) according to the magnetic field requirement, and the frequency and the high-level duty ratio of the control signal are set by the CPU according to the actual requirement.

The energy and dose rate of X-rays generated by the accelerator can be controlled by using the device and the control method thereof.

According to the LC oscillation principle, the charging and discharging processes of the capacitor bank and the main excitation coil are controlled through a specific control method, and the changed current is generated on the main excitation coil to excite a corresponding changed magnetic field for accelerating and controlling electrons of the small-sized electron induction accelerator.

The traditional excitation power supply device adopts an inverter circuit and a step-up transformer, the power supply structure is complex, the devices are heavy, the IGBT is used for controlling LC oscillation, the power supply structure is simplified, the size and the weight of the power supply are reduced, and the IGBT can be well applied to a small-sized electronic induction accelerator, which is the greatest advantage of the invention.