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, the flux-weakening IPM (FW-IPM, L_q >; L_d) and the flux-intensifying IPM (FI-IPM, L_q <; L_d) are investigated. Simulation with 3D finite-element analysis (FEA) is used to analyze loss characteristics of the machines. Iron losses and eddy-current losses in permanent magnets dominate during high-frequency carrier signal injection. The magnet eddy-current loss is found to be dependent on the magnet locations and sensitive to loading, while the iron loss is dependent on stator and rotor structural designs and less sensitive to loading. This characteristic can be used to improve position and magnet temperature sensing. Experimental evaluation of losses on a built FI-IPM machine is used to evaluate the simulation results.