Modular fault-tolerant permanent magnet brushless machines

The paper describes an analytical technique for determining all possible slot-number and pole-number combinations for modular permanent magnet brushless machines. It is shown that a large number of design variants exist. It is also shown that, for fault-tolerant modular machine designs, the adoption of a torque control strategy which minimizes the torque ripple under fault conditions may have a significant effect on the eddy current loss in the rotor permanent magnets.