NEW CONCEPT OF PERMANENT-MAGNET EXCITATION FOR ELECTRICAL MACHINES - ANALYTICAL AND NUMERICAL COMPUTATION

A new mode of permanent magnet excitation [1,2,3,4] consisting of segments magnetized nonradially, with different directions of magnetizations (see Fig.1b and 1c), produces quite new solutions to the critical problems of the permanent magnet excited electrical machines. We derive analytical formulae to calculate the magnetic flux distribution in different configurations of non-radially excited machines (stator or rotor excitation, with and without soft iron return yoke). We also use a numerical method to compute the flux distribution in a 6-pole motor with the excitation on the rotor and in a large 48-pole machine. The advantages of the new excitation (Fig.1b, and 1c) compared with the usual radially magnetized magnets (Fig.1a) are discussed.