Implementation of the PWM pre-calculated technique for elimination harmonic using microcontroller

This paper deals with the problems of harmonic pollution generated by the DC-AC converters and its reduction techniques. The study is carried out on a single-phase pulse width modulation (PWM) inverter with pre-calculated commutation angles. The algorithms are implemented on a PIC 18F4550 microcontroller and allows the obtention of a sinusoidal output current with low distortion, the quality of the output voltage waveform is evaluated by the use of Fourier spectral analysis. The optimization consists on the resolution of a set of equations issued from different criteria such as certain harmonics cancellation or, more generally, on distortion minimization. We prouve here that by accurate switching angle calculations and control, we can completely cancel low order harmonics. This is ensured in the inverter by a high precision algorithms programmed on the microcontroller system.