Modular Permanent Magnet Machine with Fault Tolerant Capability

Modular permanent magnet machines are gaining popularity due to their simple stator construction and machine winding fabrication. In this paper, a multiphase modular permanent magnet machine is proposed to obtain a robust drive system with the feature of fault tolerant capability. By making use of concentric winding on each module, the stator winding structure is simplified with benefit of less end winding loss, which also offers the operation with standard half-bridge control or even independent phase winding control. In this investigation, a modular PM machine with tooth to pole ratio close to unity design based on soft magnetic composites (while not limited to SMC) is discussed and tested. The general purpose sizing equations, with analytical model have been developed for the machine design, as well as the FEM analysis for the verifications. The fault tolerant capability of single and multiple phase winding open and power switch failures are validated by a prototype machine drive system.