Design And Implementation Of Superconducting Magnet Excitation Power Controller

Single crystal silicon is widely used in many fields,especially in semiconductor industry.With the increasing demand of semiconductor integrated circuit devices for large diameter and high quality single crystal silicon,It become a hot topic in the academic field that how to reduce the content of oxygen,carbon and other magazines in single crystal silicon and improve its axial and radial uniformity.It is found that the thermal convection in silicon melt can be effectively suppressed by adding magnetic field in the crystal growth process,and the quality of single crystal silicon can be improved.Therefore,this topic focuses on the magnetic field control system and its most important magnetic field power supply system.And details of the work are as follows:Firstly,According to the research of the power control algorithm,this paper uses a new variable structure digital controller to control the switching power supply and solves the control performance of the switching power supply.The Buck circuit with resistive load is modeled.On this basis,in view of the buffeting problem of the traditional sliding mode variable structure controller,a fuzzy sliding mode controller for switching power supply is designed by combining the advantages of two methods of fuzzy control and sliding mode variable structure control.The fuzzy sliding mode controller can soften the control signal by fuzzing the switching coefficients,which can alleviate the chattering problem of the traditional sliding mode variable structure control.Compared with traditional switching power supply,it has better performance.Matlab/Simulink simulation model is established to verify the effectiveness of the fuzzy sliding mode variable structure algorithm,and the best fuzzy rules and variable structure parameters are determined..Secondly,the power control system based on ARM+DSP is designed,including the communication part of the ARM controller,the touch screen part,the digital filtering part of the DSP controller,the fuzzy sliding mode control part,the PWM wave production part and other related software and hardware designs,which constitute the digital controller to realize the superconducting power in the output current mode.The correctness of the designed algorithm is verified by control.Finally,the magnetic field control system of Single crystal silicon pulling equipment is analyzed and studied.The system mainly includes the magnetic field power supply control part and the magnetic field position control part.The host computer displays the MCGS touch screen,and the main control adopts the SIEMENS PLC S7-200 drive inverter to control the direction and speed of the motor,to ensure that the magnetic field device stops in the set position,and has the upper and lower limit protection.