The effect of offset error and its compensation for a direct torque controlled interior permanent magnet synchronous motor drive

This paper investigates the problem caused by the DC offset in measurements to the estimation of stator flux linkage and torque in direct torque controlled interior permanent magnet synchronous motor drive (IPMSM). Modeling and experimental studies on a direct torque controlled drive are carried out with a conventional integrator which suffers from unacceptable drift of the stator flux estimation and a programmable, multistage cascaded low-pass filter, with a view to remove the drift caused by the offset. Results from these studies are presented