Sensorless position estimation of Permanent-Magnet Synchronous Motors using a nonlinear magnetic saturation model

We propose a new sensorless position estimation method of Permanent-Magnet Synchronous Motor (PMSM) at low speed by high frequency (HF) voltage injection. This method relies on a parametric saturation model of PMSM. The rotor position is estimated from the high frequency current using averaging calculations and a magnetic saturation model. Experimental results show clearly that the rotor position can be accurately estimated for different types of PM motors such as interior magnet and surface mounted, even at large angles. The estimation error is less than five electrical degree even at low speed and high load torque.