Abstract
A sensorless flow rate measurement has been proposed to control a flow rate in a magnetically levitated centrifugal blood pump without any flow sensor. The proposed algorithm consists of a linear function of the flow rate and the ratio of rotational torque to rotational speed of the impeller. In the range between 0 and 10 L/min with a working fluid of water, the error of the estimated flow rate using directly measured torque was less than 0.51 L/min, which was about a half of the equivalent value using the torque estimated from motor power consumption. Using several working fluids whose viscosity ranged from 0.75 to 3.29 mPa・s, the viscosity was estimated with the error of less than 0.16 mPa・s, from the directly measured torque when the outlet was clamped. Estimated flow rate, compensated by the estimated viscosity, showed the error of less than 0.77 L/min in the range of up to 10 L/min.
