A correction circuit of Hall-sensor-signal-based speed measurement for BLDC motors

摘要

This paper proposes a novel circuit for correcting the errors occurring in the speed measurement of a brushless DC (BLDC) motor with Hall sensors that are built in for commutation. Although the poles of the rotor are always placed with a uniform angular separation, the Hall sensors may not. The angular misalignment between the poles and the Hall sensors will cause errors in the speed measurement. With a method previously proposed to estimate the degree of misalignment, the speed errors can be minimized by our proposed circuit. This circuit is implemented in an FPGA with the aid of a hardware description language and is validated by the simulated results.