A strategy for designing of customized electromechanical actuators of blood pumps.

Abstract

Congestive heart failure is a pathology of global incidence that affects millions of people worldwide. When the heart weakens and failsto pump blood at physiological rates commensurate with the requirements of tissues, two main alternatives are cardiac transplant and ventricular assist devices (VADs). This article presents the design strategy for development of a customized VAD electromagnetic actuator. Electromagnetic actuator is a brushless direct current motor customized to drive thepump impeller by permanent magnets located in rotor-stator coupling. In this case, ceramic pivot bearings support theVAD impeller. Electronic circuitry controls rotation switching current in stator coils. The proposed methodology consisted of analytical numerical design, tridimensional computational modeling, numerical simulations using Maxwell software, actuator prototyping, and validation inthedynamometer. The axial flow actuator was chosen by its size and high power density compared to theradial flow type. First step consisted of estimating the required torque to drive thepump. Torque was estimated at 2100rpm and mean current of 0.5A. Numerical analysis using finite element method mapped vectors and fields to build stator coils and actuator assemblage. After tests in the dynamometer, experimental results werecompared with numerical simulation and validated the proposed model. In conclusion, the proposed methodology for designing of VAD electromechanical actuator was considered satisfactory in terms of data consistency, feasibility, and reliability.