Patent ID: 9556873
Date: 2017-01-31
CPC Classifications: A61M,F04D

Claim:
1. A centrifugal pump system comprising: a disc-shaped impeller rotating about an axis and having a first magnetic structure disposed at a first surface and a second magnetic structure disposed at a second surface; a pump housing defining a pumping chamber which receives the impeller; a levitation magnetic structure disposed at a first end of the pump housing having a levitating magnetic field for axially attracting the first magnetic structure; a multiphase magnetic stator disposed at a second end of the pump housing for generating a rotating magnetic field for axially and rotationally attracting the second magnetic structure; a commutator circuit for providing a plurality of phase voltages to the stator; a sensing circuit determining respective phase currents flowing in response to the phase voltages; and a controller calculating successive commanded values for the phase voltages during a running state in response to a desired impeller speed and an angular position of the impeller that is detected in response to the determined phase currents, wherein the controller has a startup interval during which the commanded values of the phase voltages are determined in response to the angular position of the impeller and a ramping gain factor.