Research On Control Mode Of Negative Ions Extraction For NBI

Neutral Beam Injection(NBI)is one of the important auxiliary heating methods to heat plasma for Tokamak,and the reliability and stability of NBI operation affect the work of Tokamak.In this paper,the negative ion source extraction beam is taken as the object,through the key issues such as the characteristics,requirements,mode analysis and implementation of the negative ion source control are analyzed and studied,a stable and reliable beam extraction control method is proposed,the solution of the key problem was tested on the experience platform for radio frequency(RF)negative ion source.The main research contents of this paper are as follows:(1)To meet the requirements of control for negative ion source beam extraction,the overall design of beam extraction control was completed.To implement the control model research of the negative ion source beam extraction,the performance requirements of extraction the voltage for the control beam extraction was proposed in this paper,and the key technical indicators of extraction power supply was completed,and main circuit structure of the based pulse modulation technology power supply was designed,and the parameter design of main circuit for extraction power was completed,and the framework of the control system of power supply was also determined.(2)The control mode of negative ion beam extraction was analyzed and studied.According to the topology structure of extraction power supply,the circuit analysis model of extraction power supply was established,and the control characteristic of extraction power supply was analyzed,and the control strategy of output voltage for extraction power supply was put forward,and the circuit simulation model of extraction power supply system was established by Matlab,and the feasibility and reliability of the control strategy was verified by simulation,which provide theoretical guidance for implemention of the control model for negative ion beam extraction.(3)To realize various functions of the negative ion beam control,the hardware and software of the control system for the power supply are designed and implemented according to the requirements of the negative ion beam control.To solve problems of switching drive and fault logic operation,the design of power module controller was completed;to realize the functions of power output measurement and fault detection,the hardware circuit design of the high voltage side control unit was completed,to solve problems such as fault interlock protection and anti-electromagnetic interference transmission of signals,the design of the photoelectric conversion control box for the low-voltage side control unit was completed;to implement problems of switch control and data acquisition,the server software of power control system was developed in Linux operation system;and for provided the setting of power running parameters and real-time display of power supply state for the operator,the client software of power supply was developed.(4)In order to verify the stability and reliability of the design for the beam extraction control mode,the experiment of negative ion source beam extraction control was carried out.Applying the power system to RF negative ion source platform for the beam extraction experiment,the feasibility of the control method of the RF negative ion source beam extraction was verified,which laid a foundation for the development of the beam extraction experiment for RF negative ion source.The proposed control mode of negative ion source beam extraction provides a new idea for the experiment of negative ion source beam extraction,and also offers a technical reference for future high-power long pulse negative ion source beam extraction control.