Construction methods for modulated pole machines

The modulated pole machine (MPM) is known to offer high torque density utilizing permanent magnets and a three dimensional flux pattern. However, their construction requires a departure from conventional coil wound teeth formed of lamination stacks which can be a challenge. In this paper three construction techniques for MPM stators are compared: pure soft magnetic composite, pure lamination and a hybrid of the two. Simulation and practical knowledge of the build of each of these machines, including torque capability and mechanical tolerances is presented and discussed. Using the methods proposed here, it is shown that the pure laminate MPM machine has the potential to offer the greatest torque per kg of active material, yet it is the hybrid machine which delivers the highest absolute torque.