Microprocessor-Based Optimal-Efficiency Drive of an Induction Motor

A method for improving the efficiency of a slightly loaded induction motor is suggested. It is based upon the optimal-efficiency slip tracking by adjusting the voltage to frequency ratio (V/f). It has adopted the converter-inverter fed induction motor drive system. All the control loops are implemented by the Z-80 microprocessor. By this method, 10 percent or more improvement is obtained at a quarter of the full load.