Effective Predictive Flux Control for an Induction Motor Drive with an Online Estimation Procedure for Stator Transient Inductance

Abstract

This paper focuses on the presentation of an effective predictive flux control (PFC) approach for an induction motor (IM) drive. The finite control set (FCS) principle is used in order to select the inverter voltages and thus there is no need to use the pulse width modulation (PWM) strategy. The proposed control approach uses a cost function formulation in which there is no need for tuning the value of the weighting factor which is inherently present in the classic predictive torque control (PTC) approach, and thus the computational burden is effectively reduced. The proposed PFC approach is derived based on the rotor field orientation principle in which the stator flux components are utilized as control variables instead of utilizing the stator current components as adopted in the classic RFO technique. In order to get better-predicted signals with limited noise content, the stator flux is estimated using an effective flux estimator instead of using the machine voltage model. An effective online identification procedure for the stator transient inductance is proposed and analyzed in a systematic manner, which has led to an improvement in the rotor flux orientation, and thus the robustness of the controller is enhanced. The performance of the drive is tested during the normal speed operation and then during the field weakening operation. The obtained results confirm the validity of the proposed PFC control approach and the effectiveness of the identification procedure in achieving correct and precise rotor field orientation which consequently results in improving the overall dynamic performance of the drive.