Abstract
To reduce the size and cost of active magnetic bearings, a six-salient-pole active magnetic bearing (6-pole AMB) has been proposed. In the 6-pole AMB, the magnetic circuits of the x- and y- axes are magnetically coupled, making the calculation more complex. Previously, sequential quadratic programming (SQP) was adopted for optimal current calculation, and its effectiveness was experimentally confirmed. In this paper, when a coil failure occurs and the current in the failed coil becomes zero, the remaining coil currents are calculated using SQP. The SQP-based analysis shows that when the number of the failed coils is fewer than three, the coil currents required to generate the reference force can still be obtained. Experimental results demonstrate that stable magnetic levitation can be achieved even when up to three coils have failed.
