Analysis and Discussion of the Indirect Testing Method for the Losses of Permanent Magnet Synchronous Machines

The losses of permanent magnet synchronous machine (PMSM) are always cared in the machine system, since the losses mainly determine the temperature-rise and efficiency of the machine. An indirect-testing method for the losses of PMSM has been proposed in order to measure the losses without any mechanical load in the test. The aims of this paper are to analyze the influence factors on this method and discuss the application of this method. The influences of the pole-slot combination, saturation, harmonic content, and frequency on the test error are analyzed. To validate the analysis, the indirect-testing losses and the direct-testing losses are compared with the test of a PMSM prototype.