Efficiency Analysis of Three-Phase and Dual Three-Phase Induction Machine with Sinusoidal Supply

An efficiency analysis of a three-phase and a dual three-phase machine is juxtaposed in this paper. Therefore, a small-scale prototype induction machine is redesigned for multiphase operation and equal terminal voltage in order to fully exploit the benefit of power segmentation in terms of per phase current rating for high power applications. Sinusoidal supply is used to exclude the influence of time-harmonics due to inverter supply, and enable the separation of losses according to the standard IEC 60032-2. The three-phase winding of the test machine is removed after the measurement, and replaced by the dual-three phase configuration to provide equal magnetic and mechanical conditions. The approach to determine the individual losses according to the standard is modified for multiple three-phase machine. This enables a comparison of the individual loss proportion. The measurements on both machines are evaluated taking into account the standard uncertainties in measurement according to the Guide to the Expression of Uncertainty in Measurement GUM.