MDSC based PLL

Fundamental frequency components, phase angle and fundamental frequency informations are accurately extracted using MDSC-PLL.

The rapid deployment of renewable energy sources and power electronics based loads into power system leads to power quality degradation. To tackle this issue, the custom power devices are to be controlled with accurate and fast acting control algorithms. An accurate exttraction of grid voltage phase angle information is one of the features of superior control algorithms. The conventional SRF-PLL gives inaccurate phase angle during unbalanced and harmonic grid voltage conditions. Therefore, the accurate fundamental frequency components are initially extracted using dual second order generalized integrator (DSOGI) operator. Thereby, accurate phase and fundamental frequency informations are extracted by feeding DSOGI output to SRF-PLL.

It is observed that DSOGI based PLL gives an inaccurate phase angle "wt" in the presence of DC and highly distorted grid conditions which is common in Microgrid applications.

To make this process further improved, cascaded delayed signal cancellation (CDSC) operator is introduced. However, it requires large delay time and storage. To reduce them, a multiple delayed signal cancellation (MDSC) operator is introduced.
For detailed comparison between these three advanced PLLs, refer the following paper.

N. Lokesh and M. K. Mishra, "A Comparative Performance Study of Advanced PLLs for Grid Synchronization," 2020 IEEE International Conference on Power Electronics, Smart Grid and Renewable Energy (PESGRE2020), Cochin, India, 2020, pp. 1-6. (doi: 10.1109/PESGRE45664.2020.9070288)