A novel twelve-step sensorless drive scheme for a brushless DC motor

Abstract

This paper presents a novel twelve-step sensorless drive scheme for a three-phase brushless DC motor, which combines the traditional six-step 120 degrees and 180 degrees conduction modes and has varied active angular period. The proposed scheme is implemented on a single FPGA-chip. Several experiments for various active angle periods from 124 degrees to 168.75 degrees are undertaken. The experimental results show that the torque constant is larger for the larger active angular period.