Induction motor efficiency maximizer using multi-layer fuzzy control

An extension to fuzzy control, multi-layer fuzzy control (MLFC), is applied to efficiency maximization of induction motors. The efficiency of induction motors decreases when the operating point deviates from the rated speed and torque. The MLFC based efficiency maximizer reduces the input electric power by adjusting the voltage to frequency (V/Hz) ratio. This is done by a coarse adjustment which moves quickly to the neighbourhood of the optimal V/Hz ratio and a fine adjustment which converges slowly to the optimum. The MLFC efficiency maximizer is tested in the laboratory and its effectiveness is verified.