TITLE:
A SRF-PLL Control Scheme for DVR to Achieve Grid Synchronization and PQ Issues Mitigation in PV Fed Grid Connected System
AUTHORS:
Saritha Natesan, Jamuna Venkatesan
KEYWORDS:
Photovoltaic (PV), Multi-Level Inverter, Total Harmonic Distortion (THD), Power Quality, dq Frame
JOURNAL NAME:
Circuits and Systems,
Vol.7 No.10,
August
16,
2016
ABSTRACT: This paper presents the
Synchronous Reference Frame Theory (SRF) based Phase Locked Loop (PLL) to
enhance the performance of Dynamic Voltage Controller (DVR). In a grid connected power conversion
system, a critical component is the Phase-Locked Loop (PLL) that generates the
grid voltage’s frequency and phase angle for the grid synchronization. For grid
voltage control, accurate and fast responding PLLs are required to provide
phase angle and frequency measurements of the grid voltage. Therefore, SRF
based PLL is presented in this work and it calculates the phase angle
accurately and effectively. This paper also presents a novel feedback mechanism
for SRF-PLL which uses the estimated frequency and phase to achieve grid
control. The fundamental signal
of the grid voltage is extracted by low pass filter and a unit value controller
to generate a unity sine reference signal for the feedback network. In
particular, the performance of the SRF-PLL in the three-phase PV fed grid
connected system is analyzed under the different power quality issues such as
voltage sag and swell. In addition, a
detailed study on synchronous reference frame theory is presented. An
appropriate control algorithm for DVR is developed and the validity of the
proposed configuration is verified through MATLAB simulation results as well as
experimental results under different operating conditions.