Design and Performance Analysis of Synchronization techniques under Non-Ideal conditions

This paper discusses the design and performance aspects of synchronization techniques. First, the symmetrical optimum is a method to design a PI regulator gains, which is used in conventional SRF-PLL. This PLL is an extensively used synchronization method to connect a grid side power converter to the grid. Under ordinary grid circumstances, high-bandwidth of PI-regulator gains in SRF-PLL provide a quick and accurate detection of grid voltage amplitude and phase angle. However, under non-ideal conditions, the phase angle could be tracked but with less accuracy. How to further enhance their dynamic output during non-ideal grid situation is a significant challenge with the SRF-PLL. This paper discusses a second synchronization method based on a generalized integrator-frequency loop (SOGI-FLL) in second-order to solve this problem. A new SOGI-FDE-FLL consisting of SOGI-FDE and SOGI-FLL is used to quickly detect accurate monitoring of grid voltage, frequency and angle of phase. SOGI-FDE is used to identify a fundamental positive sequence voltage under unbalanced conditions. The effectiveness of the SOGI-FDE-FLL is confirmed through simulation and compared with Type-2 SRF-PLL.