| ITER sensor test platform is based on the "International Thermonuclear Experimental Reactor" experimental platform,and gradually developed into the domestic advanced sensor calibration laboratory.Its steady-state current test platform is used to test the output characteristics of current sensors in a bidirectional steady-state high current,which has a 120 kA steady-state current test capability.The test platform can not only meet the testing requirements of the existing 40 kA current sensor,but also can satisfy the 60 kA test conditions for future PF supply current sensor.The power supply studied in this paper is to provide high-precision and bidirectional adjustable current for the steady-state current test platform,which is the most important equipment.In order to ensure the stable output of the power system and implement the protection and remote control of the system,the power supply and control system of the ITER sensor test platform are studied in this paper.The power supply for ITER sensor test platform has the characteristics of high output current accuracy,large output voltage and good steady-state performance and so on.Therefore,the cascaded H-bridge inverter technology and carrier phase shift pulse width modulation(CPS-PWM)are used to meet its high power output and high precision requirements in this paper.Describing the topology and working principle of the cascaded H-bridge inverter,its mathematical modeling.Based on the analysis of the existing carrier phase-shifted PWM strategy used in cascaded H-bridge inverter,the output voltage and current characteristics are deduced.The feasibility of using CPS-PWM control strategy for cascaded H-bridge inverter control is verified theoretically.In order to make the power supply realize the output current to track a given waveform and achieve the required steady-state index,the control system of the power supply has been researched and designed thoroughly.From the local control system to the remote control system,from hardware circuit design to software Programming,from device selection to device communication,from the current closed-loop to the voltage open-loop control strategy algorithm implementation,from the data read to the waveform display.Finally,the power supply digital control system is designed based on DSP + CPLD.In this paper,a more comprehensive theoretical analysis,simulation analysis and experimental analysis of the main circuit topology and control strategy of ITER sensor test platform power system are carried out.The main circuit and control part of power supply are modeled and simulated.The simulation is carried out in MATLAB/Simulink software and verified on the ITER sensor steady-state current test platform.The experimental results show the effectiveness of the control system. |
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