Design, Modeling, and Control of an IPMSM With an Asymmetric Rotor and Search Coils for Absolute Position Sensorless Drive

In this paper, a design methodology and control algorithms of an interior permanent-magnet synchronous machines (IPMSM) for absolute position sensorless drive are proposed. In conventional research on absolute position sensorless control, initial motion of the rotor was inevitable, which was not preferred in many applications. In order to eliminate the initial motion, an IPMSM with an asymmetric rotor and search coils is devised. In the proposed IPMSM, the information of the absolute position is included in the voltage signals at the search coils. By measuring and analyzing the search coil voltages, the absolute position can be estimated without any initial motion of the rotor. Overall performances of the proposed motor are evaluated through rigorous finite element analyses and experimental tests.