Dynamic search technique for efficiency optimization for variable speed induction machine

This paper proposes a dynamic search algorithm (DSA) based loss model controller (LMC) for the online efficiency optimization of induction motor drives. The algorithm incorporates a fast search process and a simplified loss model-based control, while updating the equivalent core loss resistance in the model. It ensures very fast convergence without any torque pulsations and a priori knowledge of the motor loss related parameters. A simplified d-q based model for the motor and the loss function is proposed to arrive at an approximate flux reference for any operating point. Then this flux reference is modified through a dynamic search algorithm (DSA) for optimal operating point at any load condition. The approach is simple and requires no additional hardware for practical implementation. Simulation and suitable experiments show a close agreement to confirm the validity and usefulness of the proposed technique.