Sinusoidal Brushless Drive with Low-Cost Linear Hall-Effect Position Sensors

This paper presents a low-cost ac brushless drive, which is obtained by the employment of linear Hall effect ICs for the generation of current references in the three-phase stationary reference frame. In this way, the traditionally adopted position sensor (i.e. absolute or incremental encoder, resolver, etc.) can be eliminated, thus obtaining a considerable gain in terms of costs and reliability. Moreover, if the back e.m.f. presents some harmonic content, the same drive allows to increment the output power with respect to a conventional sinusoidal drive. Finally, it can be directly employed also in dc brushless drives, without any modification and maximising power output.