Zero-order three-phase phase-locked loops

Abstract

A method of minimizing dynamics and reducing phase error towards zero for arbitrary input frequency/phase while maintaining stability in three-phase phase-locked loops is presented. Theoretically, the system transfer function becomes of zero order and the error is zero. Practically, the steady state phase error is zero and the system is of minimum dynamics/order. The method is in synthesizing a feedforward control that is added to the standard three-phase phase-locked loop. The feedforward comprises an inverse feedforward control principle relative to the part of the feedback loop seen after the summing junction.