Novel estimated back EMF ZDP based sensorless controlled BLDCM using unknown input observer

Abstract

In this paper the phase back EMF Zero Difference Point (ZDP) detection based sensorless control has been applied with the estimated back EMF using unknown input observer. The performance of VSI fed BLDC has been studied with various load torque and input speed reference. The phase to phase back EMFs estimated by the unknown input observer is used in place of Phase back EMF differences to get Zero Difference Points (ZDP). The proposed method has improved performance due to low to extra high speed precise control together with zero speed starting. This method is sensing fault tolerant and has excellent robustness towards noise in the estimated variables.