New algorithms for generation of notches in PWM waveforms using linear block codes

Abstract

The authors describe a method for the elimination of harmonics in pulse-width-modulation (PWM) waveforms using the algebra of linear block digital codes which substitutes harmonic generator polynomials, with zero and unity coefficients, for the nonlinear equations required in Fourier series harmonic elimination. The method shows that a single polynomial can be defined to eliminate a very large set of harmonics. Transcendental equations obtained in PWM waveform harmonic elimination using Fourier series of linear algebraic equations using Walsh series are replaced by linear block codes. One generator vector may cancel unwanted harmonics. The software is very simple; memory requirements are greatly reduced; and advances in microprocessor technology and speed make this mmm most advantageous for harmonic elimination in real-time systems.<>