Design And Implementation Of Gyrotron Filament Power Supply System

High-power millimeter-wave gyrotrons are widely used in the fields of national economy and national defense and military industries such as communications,Ceramic sintering,microwave weapons,millimeter-wave radars,etc.Filament power supply is an important component that provides emission electrons to gyrotron cathode.Filament power supply is required to have strong anti-interference ability,output current with high stability,wide output range,simple adjustment and be not affected by environmental changes.Based on some problems in the use of gyrotron filament power supply such as insufficient output current stability,low anti-interference performance,and low transmission efficiency,this paper designs and makes a prototype of a gyrotron filament power supply with excellent performance.First,through studying basic theory of filament power supply,according to design requirements filament power supply,topological structure of filament power supply is determined based on switching power supply theory.Based on the traditional full-bridge converter,a new circuit topology of filament power supply is proposed.The topology is the two-stage synchronous BUCK voltage-fed full-bridge circuit,which improves conversion efficiency of filament power supply,increases output adjustment range,and is suitable for any different input voltage and load,and has stronger applicability.Then control strategy of filament power supply is selected.This paper compares low-voltage sampling control strategy and high-voltage sampling control strategy,and then proposes a new double closed-loop low-voltage sampling feedback control strategy,which greatly improves stability and dynamic response characteristics of filament power supply system.Afterwards,through research of Synchronous BUCK circuit,full-bridge circuit and transformer,this paper determines parameters of each part of circuit components,and introduce parameter design process of transformer in detail,and use PSpice simulation software to perform open-loop simulation on main circuit of the filament power supply to verify the rationality of parameter design.After that,small signal model of filament power supply is established,the amplitude-frequency characteristics of filament power supply topology are analyzed,the double closed-loop feedback control circuit was designed,compensation network was introduced,and the closed-loop simulation of main circuit of filament power supply was carried out through PSpice simulation software,and circuit parameters were simulated.The dynamic response characteristics of filament power supply when a sudden change occurs in some parameters,verify the effect of double closed-loop feedback control loop.Finally,through testing filament power prototype,the waveforms of the important nodes in the prototype are measured,and the data of the circuit nodes with different output current are collected to analyze the working efficiency of the prototype at the same time,which provides a basis for further optimizing the circuit design and fully verifies the correctness and feasibility of the filament power design process.Through designing filament power supply,the results show that when filament power supply adopts the two-stage synchronous BUCK voltage feed full-bridge topology,and double-closed loop low-voltage sampling feedback control mode,the efficiency and stability of filament power supply can meet the design requirements.