The Feedback Control System For NNBI Accelerator Power Supply

To realize the fusion ignition conditions,the Tokamak device contains various auxiliary heating systems.Among them,the neutral beam injection system has the advantages of simple and clear principle and high heating efficiency,and is one of the most important auxiliary heating technologies in the fusion device.The neutral beam injection system is an essential technology to realize the long pulse output of the fusion device.The NNBI accelerator high voltage power supply is the direct source of accelerating particle energy in the neutral beam injection system.Therefore,the research on the high voltage power supply is of great significance.Based on the high voltage power supply project of the negative ion source neutral beam injection system of CRAFT,the NNBI accelerator power supply is studied in order to design a reliable feedback control system.First of all,this paper investigates the high-voltage power supply schemes of the auxiliary heating technology of fusion devices at home and abroad,and compares the situation of various schemes,in order to understand the advantages of the inverter DC high-voltage power supply.According to the high voltage power supply project of the negative ion pole neutral beam injection system of CRAFT,the circuit topology is analyzed and the parameters are designed accordingly.This paper focuses on the front stage rectifier system,isolated DC step-up converter system and isolated step-up transformer system.According to the circuit topology of NNBI accelerator high voltage power supply,a new fast modeling method of inverter DC high voltage power supply is proposed to establish the mathematical model between the inverter control signal and the load output voltage,and the output voltage control system is actually designed.At the same time,the mathematical model between the load output voltage and the DC bus voltage and the duty cycle of the inverter IGBT is analyzed to optimize the output voltage ripple of the single-stage power supply under the control of the output voltage,and the overall output voltage ripple is reduced through the series double-stage and inverter phase.For the DC component existing in the inverter,the causes are analyzed,and an DC component control system is designed to suppress the DC component of the inverter and protect the post-stage step-up transformer system.Based on the theoretical analysis and control system design of this paper,according to the project scheme of the high voltage power supply of the negative ion pole neutral beam injection system of the CRAFT device,the simulation model of the single-stage200 k V/28 A and bipolar 400 k V/28 A inverter DC high voltage power supply is built in this paper.At the same time,a set of NNBI accelerated extreme high voltage power supply1200V/5A experimental platform is designed to verify the theoretical analysis and test the reliability of the control system design.Finally,according to the simulation results and data waveforms of the simulation model and experimental platform,it is determined that the theoretical analysis in this paper is feasible,and the control system designed by this method has certain reliability.The relevant research results have certain reference value for the design and operation of the high-voltage power supply feedback control system of the negative ion pole neutral beam injection system of the actual CRAFT device.Figure 37 table 15 reference 59...