Selective Harmonic Elimination Control for Cascaded Digital Power Amplifier

In this paper, the selective harmonic elimination (SHE) strategy for cascaded digital power amplifier is derived and proposed. To solve the problem of slow iteration speed or even non-convergence of the traditional iterative method when the number of levels or the number of harmonic elimination equations is large, a new solution method based on "interior point method" is introduced. In practical application the dead-time cannot be avoided, so the impact of dead-time on selective harmonic elimination strategy is also analyzed. Based on the relationship between output voltage and current during dead-time, the control method of "flexible insertion of dead-time on line" is proposed, which can significantly weaken the dead-time effect on selective harmonic elimination strategy in practice.