Development Of High Voltage TWT Power Supply Based On Silicon Carbide Diode

With the development of space radar technology,the technical requirements of aerospace traveling wave tube amplifiers are getting closer to high efficiency,high density and high reliability.As the core part of aerospace travelling-wave tube amplifier,the high voltage traveling wave tube power supply has a direct impact on the working life of the travelling-wave tube.It is urgent to improve the working performance of TWT high voltage power supply,to adapt to the technical development.Silicon carbide devices show remarkable performance in switching speed,high pressure resistance,high temperature resistance and so on.Based on the advantages of silicon carbide diode,such as small reverse recovery current,strong critical breakdown field and high thermal conductivity,this thesis designs and produces a traveling wave tube high voltage power supply using silicon carbide diode.Firstly,the developments of traveling wave tube amplifier and high voltage power supply at home and abroad are briefly introduced.The development and device characteristics of silicon carbide diodes are briefly introduced.At the same time,the related theories of switching power supply technology are introduced and analyzed,including the basic topological structure of power supply,feeding mode and working principle of rectifier circuit.Secondly,this thesis studies detailly on the overall structure and the design and function of each part of the traveling wave tube high-voltage power supply based on silicon carbide diode developed,which are mainly divided into the main design and topology of the low-voltage circuit of the power supply and the design of the high-voltage circuit of the power supply.Low-voltage circuit consists of input filter circuit,boost converter circuit,full-bridge inverter circuit,control circuit,protection circuit and remote control and telemetry circuit.High voltage circuit is mainly composed of high voltage transformer,high voltage rectifier circuit and helix regulating circuit.This thesis mainly focuses on the in-depth analysis and calculation of the design of various parts of the high-voltage circuit,including the selection of transformer core material and shape,the method of calculating core size,the calculation of circle number and wire diameter of primary and secondary winding conductors of high voltage transformer,the calculation of the core window utilization factor,the calculation of the loss of high voltage transformer,the design of high-voltage transformer structure,and the design of output rectifier and filter circuit.Then,other technical difficulties in the development process are briefly explained,including the construction of building low voltage and high voltage simulated load,designing electromagnetic compatibility,encapsulating high voltage circuit.Finally,the test process and test results of the engineering prototype are presented.By comparing the test data of silicon carbide high-voltage power supply and traditional silicon-based high-voltage power supply,it is concluded that the application result of silicon carbide diode in wave tube high-voltage power supply is superior to that of imported silicon-based diode.