Design and analysis of a five-phase interior permanent magnet generator with a non-integer number of stator slots per phase

Traditional electric machine design requiring the balancing of the phases both in phase voltage magnitudes and the angles between adjacent phases informs that the number of stator slots per phase must be an integer. There are situations however, where it is cheaper to use existing laminations for designs with non-integer number of slots per phase to build generators for specialized applications especially for DC power. In such cases a multi-phase design ensures a measure of fault tolerance and the unbalances in the phase angles between the winding phases have little effect on the quality of the output DC voltage. The methodology for the design of a five phase, 4-pole interior permanent magnet (IPM) generator using 36 slots as a source of DC power is outlined. Experimental results for the operation under healthy and faulty conditions (one and two phase windings open) are presented for verification of fault tolerance of multi-phase machines.