Ringed-pole permanent magnet synchronous motor for position sensorless drives

The paper deals with a new configuration of SPM motor, in which a turn has been wound around each pole in order to modify the direct axes flux linkage dynamics while preserving the quadrature axis one, thus creating a rotor dynamic anisotropy. Consequently, the motor can be used in a position sensorless control drive which exploits the anisotropic rotor features by high frequency injected signals. In the paper, a complete description of the machine is reported together with the main equations that describes the motor dynamics. Expected drive performance is validated by simulation and experimental results.