Loss-minimising control scheme for induction motors

Minimisation of the loss in the induction motor is directly related to the choice of the flux level. The higher the flux level, the larger the iron loss. But extreme minimisation causes a high copper loss. There is an optimal flux level that guarantees loss minimisation, and the loss-minimisation algorithm (LMA) was derived by many researchers. However, a technical problem in deriving the LMA lies in the loss model simplification. A loss model simplification is made with a voltage dependent source and loss resistance. The optimal LMA method extends to the field-weakening region where the voltage and current constraints constitute boundaries. A complete loss-minimising control algorithm is proposed and its validity is demonstrated by simulation and experimental results.