Initial rotor position and magnet polarity identification of PM synchronous machines based on numerical simulation

In this paper a comprehensive nonlinear model of surface mounted permanent magnet (PM) synchronous machine (SPMSM) is developed considering both the structural and saturation saliencies. After experimentally identifying all the parameters, a nonlinear mathematic model of SPMSM is built, in which the rotor position and stator current are taken as the variables to calculate the inductances. A pulse injection based scheme is proposed to detect the initial rotor position and magnet polarity. A rotor vibration analysis is carried out to finalize the injected signal. The saturation saliency embedded in the nonlinear model is utilized to identify the rotor polarity, which is essential for starting the SPMSM. Simulations are taken for several different rotor initial positions and the result shows that the proposed method is suitable for the SPMSM drive.