The presence of higher order harmonics causes problems in the quality and efficiency of energy supply by voltages sinusoidal inverters (VSI) to pulse-width-modulated (PWM) of the asynchronous motors drives, widely used in industry. This paper proposes an artificial neural network that identifies the quality of the sine wave and calculates the efficiency of electric drive system according to the index modulation of the sine wave voltage delivered to the electric motor, along with inverters modulated devices semiconductors (IGBTs). Also shown the effect on the efficiency of the operation of the harmonic losses.