Structural Design Optimization Of Cusp Magnetic Device

With the development of electronic information industry,the quality of single-crystal silicon is required to be higher and higher,which means higher purity,uniformity and integrity,and big diameter as well.Previous researches showed that as the cusp magnetic field was used to single-crystal growth,the oxygen concentration in the crystal could be reduced obviously and the radial uniformity of oxygen improved at the same time.Although the big diameter cusp magnetic device has been worked out in domestic,there still exist some problems,such as the ideal feature of cusp magnetic field has not been reached,the power consumption and magnetic losses are bigger,and so on.These problems could be solved by optimization of the cusp magnetic device existed.At the beginning,the 2D magnetic simulation analysis and coil's thermal work analysis of the cusp magnetic device were conducted under multi-physics environment,and then the mathematic models of optimization and coil's thermal work optimization of the cusp magnetic device were established respectively,based on its structural characters and design requirements.On basis of selecting optimization methods and optimization tools provided by ANSYS's design optimization module reasonably,the overall optimization process for the problem were parameterized by APDL language,and the two single-objective optimizations(structure or coil's thermal work of the device)were realized successfully.The results of optimizations shows that the optimal structural parameters can meet the case of design index as much as possible,and the reduction of current makes the coil's thermal work decrease;The coil with four cooling water roads has better cooling effect and lower work of single water road than one with three.Secondly,two single-objective optimization of the device were worked on by software ISIGHT once again.Two groups of results from ISIGHT and ANSYS were in accordance with each other.Finally,with regard to the problems of the cusp magnetic feature,the power consumption and magnetic losses etc.,multi-objective optimization of the device were worked on by NCGA algorithm of software ISIGHT successfully.The optimization result shows that the optimal structural parameters can optimize the magnetic character requirements,reduce the work consumption and magnetic losses,which can further improve the cusp magnetic device's entire design performance.