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.

selective harmonic elimination, interior point method, dead-time effect elimination