Experimental verification of GEPLL architecture performance for grid connected inverter

Abstract

In order to guarantee the proper operation of grid-connected power converters, a correct synchronization with utility networks is required to extract quickly and precisely the fundamental signal. This paper presents an experimental verification of the performance of an architecture called Generalized filtering Enhanced Phase-Locked Loop, proposed in [1] to detect the amplitude, the frequency and the phase of a sinusoidal signal from a noisy measurement. The considered application regards the synchronization of the power converters with the utility network. The GEPLL scheme is characterized by an error filter and a phase-feed forward term that are embedded in the estimation algorithm for improved noise rejection and transient performances. By properly selecting the transfer function of the error filter the transient dynamic performance is improved. The presence of measurement bias and the effect of high frequency noise and harmonics are taken into account by suitably selecting the parameters of the Phase Locked Loop. Both the single and three phase grid connected power inverter systems are considered. The comparison with the original Enhanced Phase- Locked Loop shows the superior performances of the proposed Generalized filtering Enhanced Phase-Locked Loop.