Introductory Tests to In Vivo Evaluation: Magnetic Coupling Influence in Motor Controller

Abstract

An implantable centrifugal blood pump has been developed with original features for a ventricle assist device (VAD). This pump is part of a multicenter and international study with objective to offer simple, affordable, and reliable devices to developing countries. Previous computational fluid dynamics investigations were performed followed by prototyping and in vitro tests. Also, previous blood tests for assessment of hemolysis showed mean normalized index of hemolysis (NIH) results of 0.0054 ± 2.46 × 10⁻³ mg/100 L (at 5 L/min and 100 mm Hg). To precede in vivo evaluation, measurements of magnetic coupling interference and enhancements of actuator control were necessary. Methodology was based on the study of two different work situations (1 and 2) studied with two different types of motors (A and B). Situation 1 is when the rotor of pump is closest to the motor and situation 2 its opposite. Torque and mechanical power were collected with a dynamometer (80 g/cm) and then plotted and compared for two situations and both motors. The results showed that motor A has better mechanical behavior and less influence of coupling. Results for situation 1 showed that it is more often under magnetic coupling influence than situation 2. The studies lead to the conclusion that motor A is the best option for in vivo studies as it has less influence of magnetic coupling in both situations.

Implantable Centrifugal Blood Pump With Dual Impeller and Double Pivot Bearing System: Electromechanical Actuator, Prototyping, and Anatomical Studies

“…4b). The third option for motor topology was another radial electromagnetic flux motor with outer stator and theoretical mechanical power of 9.5 W at 2000 rpm (8). In this option, a passive magnetic bearing could be positioned inside the motor (Fig.…”

Review of Introductory Tests to in Vivo Evaluation, Prototypes Assembling and Anatomical Position Studies after Five Years

“…Figure 2. Also, previous blood tests for assessment of Hemolysis shown mean NIH results of 0.0054 ± 2.46 x 10-3 mg/100 L (at 5 L/min and 100 mmHg).In order to precede in vivo test, measurements of magnetic coupling interference and enhancements of actuator control were necessary.Since the first publication of introductory tests results in 2011, new findings were achieved and they are described in this review paper [3]. …”

“…Since the first publication of introductory tests results in 2011, new findings were achieved and they are described in this review paper [3]. …”

“…The motor controller was designed to drive the actuator (ML4426, MicroLinear, San Jose). Previous computational fluid dynamics investigations were performed in 2008 followed by prototyping and in vitro tests [3].The design methodologies of ICBP followed the "step-bystep" procedures proposed by Nose (1998) with previous computational simulations and introductory tests. Numerical electromagnetic simulation and the Brushless Direct Current (BLDC) motor optimizations were performed with software Flux 3D followed by prototyping and in vitro tests [4].…”

“…The motor controller was designed to drive the actuator (ML4426, MicroLinear, San Jose). Previous computational fluid dynamics investigations were performed in 2008 followed by prototyping and in vitro tests [3].…”