A New Perspective on Constraints in the Optimization of PWM Waveform Synthesis in Inverters

The mathematical formulation of pulse width modulation waveform optimization typically involves defining an optimality criterion and constraints on the switching times and other pulse width modulation parameters. In this brief, new results are presented in relation to two constraints. One constraint ensures the strict sequential ordering of switching times. The second constraint ensures that the average value of the pulse width modulation waveform over each segment matches the average of the sine wave to be generated over the corresponding segment. The significance of this latter constraint is explored and a number of new optimal pulse width modulation waveforms are defined based on the enforcement of this constraint. Numerical results of the performance of the optimal pulse width modulation waveforms are presented and compared with respect to indicators which are significant in inverters, such as magnitude of the fundamental frequency component, harmonic content and shortest switching interval of the pulse width modulation waveforms.