A Magnetic Suspension Theory and Its Application to the HeartQuest Ventricular Assist Device

: Motivated by the design of the HeartQuest magnetically levitated left ventricular assist device, closed form expressions have been developed to compute forces and stiffnesses of magnetic suspensions. The theory applies to any combination of concentric permanent magnet rings, and its accuracy and versatility were verified by experiments. The equations adapt to spreadsheet implementation and numerical optimization, providing a powerful tool of optimal design of magnetically levitated ventricular assist devices (VADs). The method was applied to the development of the HeartQuest VAD which achieved remarkable compactness and stable operation.