Large-gap Magnetic Gear Control System

Magnetic drive is a new technique which uses permanent magnetic material or electromagnetic mechanism produce magnetic force to realize the force or moment non-contact transfer. It has conquered the critical defect of work-pieces' attrition in mechanical drive, and has the unexampled advantage of mechanical drive. At present, the research of magnetic drive, such as the magnetic field of magnetic drive system and transfer electromagnetism torque, is primarily based on small gap between the initiative magnetic pole and the passive magnetic pole. At the process of mechanical heart drive research, it is the very extracorporeal magnetic driving method that effectively resolves blood pump's shortage for lacking of energy. Through the non-contact magnetic driving method, a series of difficulties on engineering and iatrology have been solved, which used to be an insurmountable drawback for tradition blood pump driving mode.In this paper, the research findings on magnetic drive technique of home and abroad is used as reaearch platform, and large gap magnetic drive axial flow blood pump as the research target and ventricular work as control objective of blood pump's output, a large gap magnetic drive system, whose initiative magnetic pole keeps static, was presented based on traveling wave magnetic field. This structure uses electromagnet instead of motor and permanent magnet, avoiding the defect for easy damage of motor under the condition of large gap and high speed. Besides, its construture is simple, and it will have the larger drive gap, better reliability and practicability, and significant innovation.Through research on this bran-new driving means, a statically electromagnet mechanical structure is proposed to realize alternating magnetic field. Based on Single Chip Micyoco (SCM), the driving control circuit is designed. Combining theoretics and experimention, energy transfer efficiency of the system is calculated. The main research contents are introduced as following:1. Based on the driving thought, in which initiative magnetic pole keeps static, designing the electromagnet mechanical structure. According to the related theory on electromagnetic field, establishing the mathematical model of magnetic induction which is produced in space somewhere by the electromagnet, and confirming its first class design parameter.2. Through analysing coupling process of magnetic field in space between blood pump and permanent rotor, gainning the pulse control mode of electromagnet coil. Based on SCM, the driving control circuit is designed, and the control program is writed. Using simulation software to modify the elements parameter in circuit, by which guiding the manufacture of circuit board.3. On the basis of computational electromagnetics and electromechanical energy conversion of electromagnetic field, the power dissipation of each energy transfer portions are getted out, and the mathematical model of magnetic field energy transfer efficiency is established, according to the analysis of energy transfer process in large gap magnetic drive system.4. The comprehensive experimental bench of blood pump is built. According to the experiments of driving blood pump, acquiring the relation curves between rotating speed of blood pump and water column height, and the relation curves between deferent current and water column height. Based on the experimental results and the mathematical model of magnetic field energy transfer efficiency, the energy transfer efficiency of large gap magnetic drive system is calculated, so as to lay a foundation for the further research on the law of the magnetic field energy transfer.