New concept of permanent magnet excitation for electrical machines: analytical and numerical computation

It is pointed out that a new mode of permanent magnet excitation consisting of segments magnetized nonradially, with different directions of magnetization, produces quite new solutions to the critical problems of permanent magnet excited electrical machines. The authors derive analytical formulae to calculate the magnetic flux distribution in different configurations of nonradially excited machines (stator or rotor excitation, with or without a soft iron return yoke). They 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 as compared with the usual radially magnetized magnets are discussed