基于横向旋转磁场的耦合原理,提出轴流式血泵外磁场驱动系统方案,设计一种泵机分离的结构。采用等效电流法建立了永磁体等效物理模型,计算血泵驱动系统的主动轮和从动轮之间的距离、相对转角以及磁极对数对血泵传动扭矩的影响。研究结果表明:在生理范围内,即主动轮与从动轮的安装距离小于60mm,设计的永磁体输出的扭矩大于血泵需要的扭矩(6.4N-mm),能够满足血泵的驱动要求。主动轮与从动轮的磁极对数是影响血泵系统性能的关键参数,主动轮与从动轮磁极对数越少,传动扭矩越大,但是扭矩波动也大;主动轮的磁极对数大于从动轮的磁极对数,驱动系统传动平稳,对控制有利。
The extracorporeal magnetic filed driving system was proposed for axial flow blood pump based on coupling principle of transverse alternating flux. The driving principle of blood was described. According to equivalent current method, the equivalent physical model was constructed to calculate the torque varying with clearance, relative angle and magnetic pole number between driving magnetic gear and driven magnetic gear of blood pump driving system. The results show that in the physiological clearance, when the distance between two gears is less than 60 mm, the torque supplied by the designed permanents is greater than the necessary torque (6.4 N·m) to drive blood pump. The smaller the magnetic pole number of magnetic gear, the larger the driving torque, but the stronger the torque fluctuating. If the magnetic pole number of driving gear is bigger than driven gear, the driving system is stable and favorable to be controlled. Hence, the proposed structure is feasible to drive blood pump.