Magnet shaping to reduce induced voltage harmonics in PM machines with surface mounted magnets

A simple methodology for reducing induced voltage harmonics in permanent magnet (PM) machines by selecting the appropriate magnet shape and dimensions is presented. The method, which uses a simplified analytical model of the magnetic circuit, is applied to three basic magnet shapes (rectangular, stepped, and trapezoidal), and can be extended to more complex geometries. The results of the analytical models are compared with results obtained from finite element analysis and with test results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>