Masahiro Osa

Chapter 11 – Motor design and impeller suspension

Motor design over the past century has been a thoroughly researched area; however, the motor requirements for rotary blood pumps (RBPs) are typically unique in nature. As with other applications, they are required not only to be highly efficient, reliable, and compact but also to possess hemocompatibility characteristics, such as large clearances between the rotor and stator and the use of noncontact bearing systems, to ensure long-term patient support. An understanding of the interaction and production of electromagnetic forces inside a motor along with control methods and design topologies is essential for developing a highly efficient, reliable, compact, and hemocompatible motor for use in a RBP.

Compact maglev motor with full DOF active control for miniaturized rotary blood pumps

Mechanical circulatory support using rotary ventricular assist devices (VADs) is one of the strongest therapy for heart disease patients. However, technical difficulties such as high mechanical durability, sufficient blood compatibility and small device size prevents VADs development for pediatric heart disease. In this study, an ultra-compact self-bearing motor whose diameter of 22 mm and height of 33 mm has been developed for durable and blood compatible centrifugal pediatric VADs. The motor employs a double stator mechanism using two identical motor stators to enhance torque production and achieve impeller suspension with an active 5-degrees of freedom (DOF) control. This paper investigated basic magnetic suspension performances of the developed self-bearing motor with the 5-DOF control. The motor achieved non-contact impeller suspension up to the rotating speed of 7500 rpm, and indicated sufficient magnetic suspension ability.