it's a ring of magnets in repulsion with magnets coupled to the electromagnets. the aim is to center the ring magnets by controlling the electromagnets. How to do that??
Are you considering passive radial bearing with active axial, or other way around? Or have I got wrong end of the rabbit?
Problem I see is passive magnetic systems like in a pair of radial bearings need to be stabilized with great precision axially. This is often done with jewel bearings and the axial loading is small. To do this with a active control system would be extravagant.
Active systems are used with pm bearings in Halbach arrays for levitation.
I agree with asimpson.
you say semi- active. This implies changing the passive elements actively.
I think you want to actively control the MBs. You would need to design a nice little control system for it. This has been done before. Look up maglev systems.