Voltage Synchronisation Techniques for Grid-Connected Power Converters

Abstract

Standard synchronisation scheme for grid-connected power converters has been known to fail to correctly estimate the instantaneous phase angle of the grid voltages which are unbalanced and corrupted with harmonics. There are other advanced schemes which have been proposed to address this issue but a thorough comparison among the schemes is lacking. This paper presents a detailed review on five advanced grid voltage synchronisation schemes. A coherent investigation is performed to compare their merits and limitations considering a wide range of voltage distortions. This is verified through simulation and practical results.

Soft switching method for multiport DC/DC converters applicable in grid connected clean energy sources

“…4, the maximum power can be obtained from the PV, while the demand power of the utility side is set to P 3 = P demand . Power flow management of the inverter side is based on the decoupled active and reactive power controlling in d-q axis [18][19][20][21]. The grid angle θ G is estimated by a single phase PLL (phase locked loop) [22].…”

A novel phase locked loop scheme for grid voltage synchronisation using the energy operator

“…This section reviews the principles of these schemes. Detailed comparisons have been discussed in detail in [16] and are summarised here briefly…”

Grid Voltage Synchronization for Unbalanced Voltages Using the Energy Operator

“…One of these applies additional filtering to remove the harmonic components from the d-q vectors [9][10][11][12][13]. Another approach extracts the fundamental positive sequence component (PSCs) initially using the Fortescue theorem [14][15][16]; it performs particularly well under unbalanced conditions, and hence has been the preferred method as it incurs the least time delays. Well-known schemes that use this method are the double synchronous reference frame (DDSRF-PLL) and cascaded delay signal cancellation (CDSC-PLL) [15,16].…”