A new method to minimize harmonic components of PWM signals based on lagrange multipliers

With the evolution observed nowadays in power electronics systems, frequency converters are increasingly used in the grid. However, due to switching techniques employed, the harmonic distortion of the resulting signals became an important parameter to be considered in the design of such converters. For this reason, special attention has been given to the techniques of pulse width modulation (PWM) aimed at reducing the harmonic content. This paper proposes a new methodology for the determination of the PWM pulses, based on the application of nonlinear numerical optimization technique using the Lagrange algorithm for minimizing an objective function. The application of this new technique enables the minimization of the total harmonic distortion (THD) at the same time that restrictions are imposed on the amplitudes of harmonic components of interest. Numerical results demonstrate the potentiality of the proposed methodology.