An Online Efficient Loss Model Controller for Rotor-Field Oriented Induction Motor Drives

This article introduces a new online loss-model controller (LMC) for maximum efficiency operation of rotor-field oriented induction motor (IM) drives. The satisfactory performance of such type of control scheme heavily relies on the precision of the loss-model. The preliminary works as reported in this context, suggest that the accuracy of the loss-model while calculating loss has been heavily compromised because of considering constant iron loss resistance throughout the operating range. On contrary, the recent works report the enhanced accuracy of the same at the cost of increased computational complexity via the inclusion of the iron loss branch current. In the proposed work, a new loss-model of IM is developed taking both variable iron loss resistance and leakage reactance into account. In this context, a generalized expression of variable iron loss resistance has also been developed. Apart from achieving the point of maximum efficiency with a fair accuracy, the other salient features of the proposed scheme are: (i) computational simplicity, (ii) fast dynamic response, and (iii) no additional cost of implementation. The effectiveness of the proposed method has been verified with experimental results, and comparative studies in a 5.5 kW IM drive using dSPACE1103 digital controller.