一种磁悬浮离心式心脏泵刚度与阻尼特性分析

针对一种磁悬浮离心式心脏泵系统的动态特性,需要分析其刚度与阻尼。为此,分析了径向永磁轴承和开关磁阻电机的径向力学特性,得到磁悬浮转子径向运动方程和控制系统框图; 并结合PD控制器,推导出系统径向刚度与阻尼数学表达式,最后通过实例仿真,得到径向刚度与阻尼特性曲线。研究表明,比例和滤波环节对系统动刚度、阻尼比和固有频率均有显著影响,且在低频段,微分系数与阻尼比近似成正比关系。上述研究为磁悬浮离心式心脏泵控制系统的设计和磁悬浮转子径向位移控制提供理论指导。

Study on Stiffness and Damping of a Centrifugal Maglev Blood Pump

The stiffness and damping of the dynamic characteristics of a centrifugal maglev blood pump, needs to be analyzed. To this end, the equation of radial motion and block diagram of control system about the maglev rotor are provided, according to the study on mechanical characteristics of radial permanent magnetic bearings and switched reluctance motors. And the mathematical expressions of radial stiffness and damping about the maglev system are deduced by combining block diagram of control system and PD controller. Finally, through the simulation example, the characteristic curves of radial stiffness and damping are presented. Studies have shown that dynamic-stiffness coefficients, damping ratio and natural frequency are obviously affected by the link of proportion and filter and derivative coefficient is approximately proportional to damping ratio on low-frequency stage. The study provides theoretical guidance for designing the control system of the centrifugal maglev blood pump and radial displacement control of maglev rotor.