Real time induction motor efficiency optimization

The induction machine efficiency optimization issue is the subject of many contributions in the literature. Few solutions, have shown interest in the rapidity-stability dilemma regarding the presence of sudden load torque variations. This paper presents a new useful hybrid approach for efficiency optimization of the direct vector-controlled induction motor drives. The efficiency improvement approach consists of adjusting the rotor flux with respect to the load torque in order to minimize total losses in the induction machine. The optimal rotor flux is defined in two steps. Firstly, the controller defines a suboptimal operating point by a fast analytical algorithm based on the model of induction machine. The suboptimal flux helps to minimize the size of possible solutions space of the optimization issue. The global optimal flux is achieved in the second step using a simulated annealing method. This latter adjusts the flux level in order to reduce the power input at its minimum. This choice overcomes the influence of parameters uncertainty on the controller stability. The proposed controller has been experimentally tested and validated on a 3 kW squirrel age induction motor.