BALANCING DEVICE STRESSES BY FUNDAMENTAL CANCELLATION

The technique of harmonic cancellation is one of the cornerstones of p ower electronics. The method relies on destructive interference of spe cific Fourier components between two or more similar but phase-displac ed waveforms. The components eliminated are traditionally harmonics of the basic operating frequency. However, there is no inherent reason w hy the fundamental cannot be eliminated. This intuitively repellent co ncept can be advantageously employed to balance device stresses in sin gle-phase applications. In this paper a typical application is examine d by simulation to illustrate that traditional methods can result in u nbalanced conditions. A method is described for deriving suitable wave forms for fundamental elimination. And finally, the simulation is repe ated with the selected waveforms to show that balance has been restore d.