New Walsh domain technique of harmonic elimination and voltage control in pulse-width modulated inverters

A new method is presented for selective harmonic elimination in pulse-width modulated (PWM) inverter waveforms by the novel use of Walsh functions. The Walsh operational matrix of pulse-width modulation (WOM-PWM) is introduced as a means of obtaining the Walsh spectral equations of PWM waveforms. The slope and intercept Fourier operational matrices of pulse-width modulation (SFOM-PWM and IFOM-PWM) are also introduced as a means of obtaining Fourier spectral equations of PWM waveforms. A noniterative algorithm is proposed that produces piecewise linear, global solutions between angles and voltage fundamental, without the need of initial starting values for the angles. The algorithm also produces the full range of variation of fundamental voltage for given harmonic elimination constraints. The set of systems of linear equations obtained replaces the system of nonlinear transcendental equations used in the Fourier series harmonic elimination approach. In general, the algorithm makes possible the synthesis of two-state PWM inverter waveforms with specified odd harmonic content.