Optimal harmonic elimination control

Abstract

Harmonic elimination and control has been a widely researched alternative to traditional PWM techniques. The equations that govern harmonic elimination have multiple solutions based on different switching angles. Each solution will result in the uncontrolled harmonic content having a unique distribution of energy. To determine which solution is optimal, a cost function must be developed for a given specific application. Typical cost functions will require evaluation significantly beyond the last controlled harmonic. This paper develops a cost function and provides experimental results for a single-phase inverter and a three-phase induction motor drive system. Ultimately, it is shown that there exists an optimal harmonic control solution for a given application which minimizes some cost function; in this case, system power loss.