Improved accuracy of sensorless position estimation by combining resistance- and inductance-based saliency tracking

At standstill and low-speed, signal-injection methods are required to estimate the rotor position of a permanent magnet synchronous machine (PMSM). Therefore, usually either the resistance- or inductance-based saliency is examined. Although the latter case can be found most in literature, it is possible that the sensorless performance can be improved by exploiting the position information of both saliencies at the same time instead of evaluating only one of both. Therefore, this paper proposes a modified position estimation method which combines both the resistance- and inductance-based saliency. Based on measurement results of a PMSM, the new method is compared to the sole resistance- and inductance-based saliency tracking.