| The magnet power supply system is an important part of the heavy ion accelerator,and the output index of the power supply determines the beam quality of the accelerator.The presence of ripples in the magnet power supply will affect the accuracy of the magnetic field,thereby affecting the performance of the accelerator.In this thesis,aiming at the problem of ripple suppression in the DC stabilized power supply of heavy ion accelerators,the current source active power filter(CSAPF)is used to suppress the output ripple current.Combined with the engineering application platform,the related technology of CSAPF is studied.The thesis analyzes the forming principle of the current ripple of the magnet power supply,and studies the CSAPF topology and mathematical model,ripple current detection algorithm,and control strategy.A comparative analysis of CSAPF and voltage source active power filter(VSAPF)from three aspects of principle,structure and working mode.Based on the unique advantages of CSAPF in ripple suppression,CSAPF is used for accelerators magnet power supply ripple current suppression;In order to improve the detection accuracy of the ripple command signal and the system response speed,a parallel SOGI ripple detection algorithm is used for the ripple detector to extract the ripple signal for the detection of the ripple current;To improve the response speed of the ripple command,the thesis uses reaching law sliding mode control(RLSMC)to control the CSAPF to improve the anti-disturbance performance and compensation performance of the CSAPF;Based on the above work,the ripple detection algorithm and control strategy are simulated and verified by using MATLAB to design the CSAPF.The simulation results show that the ripple detection algorithm and control strategy studied in the thesis are effective.On the basis of the above work,complete the CSAPF hardware circuit and software design.Modular design is carried out in the data acquisition part to enhance the portability of the data acquisition module.The power consumption and volume requirements are considered in the design.Use the MATLAB code conversion function to convert the designed ripple detection algorithm and control strategy into Verilog HDL language and integrate it into the FPGA controller,and the FPGA will generate the PWM drive signal in real time;Design the Nios II soft core to realize the communication between the host computer and the CSAPF system Network communication and PI parameter adjustment.An experimental platform was built,and the CSAPF studied in this thesis was verified experimentally by relying on the DC stabilized current power system of the heavy ion accelerator of the Institute of Modern Physics,Chinese Academy of Sciences.The experimental results show that the ripple detection algorithm and the reaching law sliding mode control strategy used in the thesis have a certain suppression effect on DC ripple when applied to the CSAPF system.The research of the thesis provides a certain reference basis for the subsequent ripple current suppression and the development and application of CSAPF. |
