Innovative design for flux leakage reduction in IPM machines

This paper presents a novel rotor design for interior permanent magnet (IPM) machines. The advantage of this solution is the near elimination of the magnet flux leakage in the rotor iron bridges, which represents the main disadvantage of this machine topology. Therefore enhanced magnet utilization results from the new rotor arrangement. The concept is accomplished by utilizing non-magnetic wedges to lock the magnet in a robust rotor structure. The study is supported by both electromagnetic and mechanical finite element analyses. Significant results of this investigation are presented and discussed in the paper. A machine prototype with the implemented innovative rotor design was manufactured and tested for validation of the finite element simulations. Several manufacturing methods of the wedge have been investigated in order to evaluate the resultant wedge characteristics and assess the feasibility of mass production. The total cost analysis yields to potential machine cost reduction.