RESUMO
In previous studies,we presented main strategies for suspending the rotor of a mixed-flow type (centrifugal and axial) ventricular assist device (VAD), originally presented by the Institute Dante Pazzanese of Cardiology(IDPC), Brazil. Magnetic suspension is achieved by the use of a magnetic bearing architecture in which the activecontrol is executed in only one degree of freedom, in the axial direction of the rotor.Remaining degrees of freedom,excepting the rotation, are restricted only by the attraction force between pairs of permanent magnets. This study is part of a joint project in development by IDPC and Escola Politecnica of São Paulo University, Brazil. This articleshows advances in that project, presenting two promising solutions for magnetic bearings. One solution uses hybrid cores as electromagnetic actuators, that is, cores thatcombine iron and permanent magnets. The other solution uses actuators, also of hybrid type, but with the magneticcircuit closed by an iron core.After preliminary analysis, a pump prototype has been developed for each solution andhas been tested. For each prototype, a brushless DC motor has been developed as the rotor driver. Each solution wasevaluated by in vitro experiments and guidelines are extracted for future improvements.Tests have shown goodresults and demonstrated that one solution is not isolated from the other. One complements the other for the development of a single-axis-controlled, hybrid-type magnetic bearing for a mixed-flow type VAD.