A novel stator flux oriented V/f control method in sensorless induction motor drives for accuracy improvement and oscillation suppression

This paper presents a novel V/f control method for speed sensorless induction motor drives. The proposed method keeps a constant steady-state stator flux in d axis by adding the stator resistance compensation. And the speed accuracy is improved by using the precise slip frequency compensation. Besides, a novel oscillation suppression compensation method is proposed to improve the stability and convergence rate of the drive system both in motoring and regenerating operations. The compensation is achieved by feeding both d-axis and q-axis dynamic current to frequency with different feedback parameters. In this paper, the linear model of this proposed system is derived and analyzed to design proper feedback parameters. In addition, the parameter sensitivities under the proposed V/f controlled method are studied based on the steady-state operating point analysis. The simulation and experimental results based on 15kW and 2.2kW IM drive systems are presented to confirm the validity the proposed method.