Investigating the stability of phase-locked loop in network-connected applications affected by microgrid-side and network-side parameters

In most today's power systems, microgrids are connected to the network through a grid-interface converter. In these converters, the phase-locked loop (PLL) is the most popular technique for network synchronization. This paper investigates the dynamic performance and the stability of synchronous reference frame PLL influenced by various factors. These factors include the network-side and microgrid-side parameters. Similar to the effect of network-side factors, the effect of microgrid components also plays an important role in the stability of the PLL. Given that the stability of PLL affected by microgrid-side parameters have not been studied yet, so in this article, after a detailed analytical modeling of microgrid components (including the production power fluctuations, energy storage system, microgrid-side loads, and controller parameters), the stability of PLL affected by different microgrid-side parameters has been evaluated. In addition, with the aim of achieving a criterion for the assessment of PLL stability, also, based on the proposed criterion, the rate of exchanged output power is determined for the grid-interface converter with the aim of guaranteeing the stability of PLL.