Magnetic Suspension Test Controller for a New Continuous Flow Ventricular Assist Device

A new continuous flow ventricular assist device using a full magnetic suspension has been constructed and tested. The magnetic suspension centers the centrifugal pump impeller within the clearance passages in the pump, thus avoiding any form of contact. The non-contact operation is designed to give very high expected mechanical reliability, large clearances, low hemolysis, and relatively small size compared to current pulsatile devices. A unique configuration of magnetic actuators on the inlet side and exit sides of the impeller give a full five axis control and suspension of the impeller. The bearing system is divided into segments which allow for three displacement axes and two angular control axes. The controller chosen for the first suspension tests consists of a decentralized set of five PID controllers. This document describes both the controller and an overview of some results pertaining to the magnetic bearing performance.