DSP-based real-time harmonic elimination of PWM inverters

Pulsewidth modulation (PWM) using a harmonic elimination technique necessitates the solution of systems of nonlinear transcendental equations. Conventionally, due to their high complexity, these equations have to be solved off-line and the calculated optimal switching angles are stored in look-up tables or interpolated by simple functions for real-time operation. System flexibility is very limited, especially for applications which require both amplitude and frequency control. A new implementation scheme based on real-time solution of nonlinear harmonic elimination equation using a digital signal processor DSP56001 is reported in this paper. Real-time generation of switching patterns that have 15 notches to be determined in each quarter fundamental period has been accomplished within 2.15 ms