Secondary resistive losses with high-frequency injection-based self-sensing in IPM machines

This paper investigates the impact of high-frequency-injection-based self-sensing on secondary resistive losses associated with the high-frequency carrier component in interior permanent magnet (IPM) machines. Two types of salient machines, a flux-weakening IPM (L-{q} > L_d) and a flux-intensifying IPM (FI-IPM, L-{q} < L_d) are investigated. Simulation with 3-D finite-element analysis is used to analyze the loss characteristics of the machines. Iron loss and eddy-current loss in permanent magnets dominate during high-frequency carrier-signal injection. The magnet eddy-current loss is found to be dependent on the magnet location and to be sensitive to loading, while the iron loss is dependent on stator and rotor structural designs and is less sensitive to loading. The understanding of this characteristic is useful for position and magnet temperature sensing. Experimental evaluation of losses on a built FI-IPM machine is used to evaluate the simulation results.