Induction Machine Analysis for Arbitrary Displacement Between Multiple Winding Sets

The steps in t he applied voltages of a three-phase, inverter-induction motor drive system cause undesirable pulsations in motortor By using multiple inverters connected to a multiphase machine with appropriate winding displacements, significant improvement in system performance is possible. The winding displacements required, however, are not necessarily the symmetrical displacements used in standard multiphase machines. This paper sets forth an improved method for analyzing many types of unsymmetrical, as well as symmetrical, multiphase induction machines. The simulation of a 7.5-hp induction machine with two three-phase sets of stator windings fed from two six-step inverters illustrates the application of the method of analysis and shows how the machine torque characteristic may be improved by proper spacing of the winding sets.