Optimization Design Of Permanent Magnetic Mechanism In High Magnetic Field

The permanent magnets with high field intensity are used in medical systems, military affair and high-energy physics fields. They are usually electromagnets or superconductor magnets at present. If we design the size of the permanent magnetic mechanism properly, there will be much higher magnetic field than its remanence in the center, and it can replace the superconductor magnet and electromagnet. So with the development of properties about permanent magnetic material, the optimization design of the permanent magnetic mechanism with high magnetic field must develop well in the future in the magnetic field.There is a kind of special permanent magnetic mechanism--permanent magic ring which is made up of permanent magnet blocks. Their magnetized direction changes equably. In the assembly complex process, the permanent magnet blocks with different magnetized direction will impact each other, and might bring the local demagnetization or saturation. So the work point of permanent magnetic material might be at the whole hysteresis loop including minor hysteresis loop. The traditional method only considers the demagnetized curve of the magnetic material, so inevitably there are some errors in simulating the magnetic characteristic in the high magnetic field.This paper presents two optimization schemes .They both introduce the soft magnetic material into permanent magic ring to reduce the effect of the demagnetization and the saturation. Programs made by Fortran Language combine a genetic algorithm with a finite element analysis and a Preisach hysteresis model. Basing on the simulating the actual properties of permanent material, the aim of optimization is to obtain the highest average density of magnetic flux in its center after the magnetic ring assembly. The optimized result is the size of the soft magnetic material in the schemes. The optimized results. are reasonable through the experiments of the traditional simplified method such as current sheet.The length of magic ring is designed by Ansoft Maxwell considering both the product cost and the intensity of magnetic field. The initial fixing position can be designed by the analysis of magnetic force at each step in fixing by Ansoft Maxwell. And they present important parameters for the tools used to fixing the permanent magic ring.