Amplitude-phase-locked loop: Estimator of three-phase grid voltage vector

This paper presents a novel amplitude-phase locked loop (APLL) to simultaneously estimate the phase angle, frequency and amplitude of grid voltage, as well as the change rate of amplitude accurately. The proposed APLL can extract pure fundamental component when grid voltage contains noise and harmonic components. Furthermore, positive-sequence voltage component can be decoupled by APLL when grid voltage is asymmetric. Moreover the effect of APLL's controller parameters on its dynamic response is analyzed. Finally, simulation and experimental results are presented to verify the feasibility and effectiveness of APLL.

I. Introduction

With the development of power electronics, more and more highly controllable devices [1]–[4] are integrated into power system. The operation of these devices relies on the accurate estimation of the positive-sequence fundamental component's characteristics of grid voltage including phase angle, frequency, amplitude and change rate of amplitude (CRA).