Investigation Of Control System And EMC Based On High Power Pulse Generator

In the process of energy compression and conversion,the voltage and current of High-Power Pulse Driver(HPPD)vary dramatically,which results in strong electromagnetic radiation.This kind of intense electromagnetic radiation can not only produce serious electromagnetic interference to the nearby electronic equipment and control system,causing their failure or even damage,but also affect the normal operation of HPPD.Therefore,it is very important to study the electromagnetic radiation characteristics,control system and electromagnetic compatibility characteristics of HPPD.The HPPD studied in this paper is a Capacitive Intense Electron-Beam Accelerator based on Blumlein pulse forming line and Tesla pulse transformer(BT-CIEBA).The theoretical and experimental research on electromagnetic radiation characteristics and ElectroMagnetic Mompatibility(EMC)of BT-CIEBA are carried out in this paper.Based on these,two sets of control system for BT-CIEBA are developed,and a control system for the synchronous operation of BT-CIEBA and a pulse magnetic field power supply is developed successfully.The main contents are as follows.1.The electromagnetic radiation mechanism during the operation of BT-CIEBA is analyzed theoretically,and the numerical calculation of radiation field intensity and spectrum are carried out.Based on Maxwell's equations,the formulas for calculating the radiated electric field and magnetic field are deduced,and the relationship between the main frequency of the radiated signal and the rising edge of alternating current is summarized.The main radiation sources are thyristor switch,high voltage pulse trigger and gas main switch(a three electrodes gas spark gap switch triggered by needle).The radiation field intensity and spectrum of the three radiation sources are theoretically deduced and calculated.The results show that the gas main switch is the uppermost radiation source of BT-CIEBA.The theoretical calculation value of the radiation electric field intensity of the gas main switch is about 3150 V/m at the distance of 10 meters.2.The electromagnetic radiation characteristics of the gas main switch are studied by theoretical analysis and experimental research.The rising edge of the conduction current of the gas spark gap switch are analyzed theoretically.The results show that the rising time of the conduction current is related to the channel length,characteristic impedance,breakdown electric field and gas pressure.The current of the gas main switch is quasi-square wave pulse current,which has fast rising(12ns)and falling(18ns)edges.Therefore,the gas main switch has dual electromagnetic radiation characteristics,that is,both of the processes of current rising and falling can produce strong electromagnetic radiation,which belongs to typical broad-spectrum radiation.The dominant frequencies are 84 MHz and 56 MHz.The radiation spectrum covers the range of 1-100 MHz.The peak value of the radiation field strength of the gas main switch is directly proportional to the current change rate.The electromagnetic radiation characteristics of the gas main switch basically conform to the electric dipole arrays radiation model with rotational symmetry.Based on the electromagnetic shielding theory,a metal shielding system is designed to shield the front radiation surface of the gas main switch.The field intensity of the gas main switch is 3280 V/m at a distance of 10 meters without shielding,which is reduced to 115 V/m by shielding.Contrast experiments show that the radiation field intensity is reduced by an order of magnitude,which is in line with the national standard of electromagnetic environment control limit(384 V/m).3.Based on the study of electromagnetic radiation characteristics of BT-CIEBA,and aiming at the need of BT-CIEBA for automatic control,the control system for BT-CIEBA is successfully developed.The key technology of repetitive operation of BT-CIEBA is to develop a control system with time sequence control method,to realize stable supplement of primary energy,synchronous trigger of the gas main switch,and to improve the anti-strong electromagnetic interference ability.A remote trigger control system based on Labview and PIC microcontroller and an improved control system based on Delphi and Field Programmable Logic Gate Array(FPGA)are developed in this paper.Long-time repetitive experiments show that the improved control system has friendly interface and strong compatibility,the hardware structure is compact and integrated,the timing precision is higher,the overall performance is stable,and the anti-interference ability is strong.4.A set of pulsed magnetic field power supply based on LC resonant charging is developed,the working principle of which is introduced,and the key technology of repetitive operation is analyzed.According to the working principle of pulse magnetic field power supply,a control system is developed to control the synchronous operation of BT-CIEBA and pulse magnetic field power supply.The stable operation of 20 Hz is realized.5.The system-level EMC analysis and design of a vehicle-mounted High Power Microwave(HPM)transmitting system are carried out,which is composed of BT-CIEBA,microwave source and antenna.EMC technologies such as grounding,reasonable wiring,electromagnetic shielding and photoelectric isolation are adopted to improve the anti-EMI capability of the vehicle platform.The vehicle platform can operate stably.