Design of an BLDC drive with iron core to improve the efficiency of Ventricular Assist Devices

Single sided Brushless DC (BLDC) drives with axial flux have the advantage of a flat design and high torque. This makes them a good choice for operating less invasive implantable Ventricular Assist Devices (VADs), which can be applied for the therapy of cardio vascular diseases. The disadvantage of such drives is the occurrence of high axial forces. In order to avoid axial forces some VAD drives have air gap windings. Their torque generation completely relies on magnetic stray fluxes. Therefore an increase in efficiency is expected when using iron teeth with single tooth windings. As iron losses have to be considered now, a study is performed to identify the key parameters for iron and copper losses. From this study an efficient VAD drive design is deduced.