Study on virtual zero power of maglev left ventricular assist device

Abstract

A virtual zero power (VZP) method was used to reduce the power consumption of hybrid magnetic bearings (HMBs) in left ventricular assist devices (LVADs). The mathematics of the HMB system in LVAD was established, and the stability was analyzed with a proportional-derivative (PD) controller. The unbalanced forces on the rotor can be identified by the output voltage of the PD controller, together with the negative stiffness of the permanent magnet, and the rotor can be suspended at a point where the rotor's reluctant force is at a minimum to lower power consumption. Experiments were conducted to measure the power consumption of the magnetic bearing at different rotational speeds, and different trajectories of the rotor were demonstrated. The results showed HMB using VZP consumed 0.28 W averagely at 1000-4000 rpm in the LVAD.