In the field of sensorless control of Permanent Magnet Synchronous Motors (PMSMs), different techniques based on machine anisotropies have been developed. This work analyzes sensorless techniques that exploit the star-point voltage of PMSMs at the aim of evaluating the applicability of such techniques by analyzing the machine inductances matrix. After a brief mathematical description of the technique, a characterization of the machine anisotropy information extracted from the star-point voltage has been performed. Finally, experimental results conducted on a custom PMSM are presented in order to validate the proposed theory.