Possible analogy between the optimal digital pulse width modulation technology and the equivalent optimisation problem

A novel nonlinear searching method, immune algorithm (IA), is presented based on the immune theory in biology. This method is applied to resolve the optimal control problem of the sinusoidal pulse width modulation (SPWM) inverter, and the IA is adopted to find the optimal digital SPWM control sequences. Furthermore, the IA well fits with on-line microprocessor implementation. A single-phase full-bridge inverter is considered, and the optimal digital SPWM control sequences are calculated to minimise total harmonic distortion of output waveform. These digital sequences are used in a simulation system and experiment setup to verify the usefulness of the method.