Harmonic control: A natural way to bridge resonant control and repetitive control

A new recursive control method named harmonic control is proposed to provide a tailor-made zero tracking error control solution to the tracking or elimination of selective harmonic frequencies. Harmonic control can exclusively choose control gains at selective harmonic frequencies, and can yield much fast convergence rate at these frequencies. It makes a good trade-off between resonant control and repetitive control: a parallel combination of multiple resonant controllers can track/eliminate selective harmonic frequencies very fast, but cause heavy parallel computation; a repetitive controller that is in compact recursive form can achieve zero tracking error at all harmonic frequencies, but yields slow convergence rates at selective harmonic frequencies. The analysis and synthesis of harmonic control are addressed. An application example of harmonic controlled three-phase PWM inverter demonstrates the effectiveness of the proposed harmonic control scheme.