Phase lock loops (PLLs) are key components of modern communi- cation systems. Frequency synthe- sizers, FM demodulators and clock recov- ery circuits are some applications of PLLs. An important aspect of PLL design is the steady state stability …

This letter analyzes the impact of a phase-locked loop (PLL) on small-signal stability in a system of interconnected grid-forming and grid-following (GFL) converters. It identifies an undiscovered instability phenomenon, i.e., the system is prone to unstable when the bandwidth of PLL used with GFL converter is low.

2020年2月13日 · In this paper, the stability of the PLL affected by the control loop under transient grid faults is studied. First, the equivalent model of the PLL under the influence of the control loop is established. Then, different response processes of PLLs under the ground fault with various control parameters are qualitatively analyzed.

stability is concerned with how the output signal varies over a long period of time (hours, days, or months). It is usually specified as the ratio, Δf/f for a given period of time, expressed as a percentage or in dB. Short-term stability, on the other hand, is concerned with variations that occur over a period of seconds or less.

In this paper, we utilize a linear time-variant (LTV) model of the PFD and CP to propose an alternative analysis that provides new insights into the behavior of CP PLLs and shows that the loop bandwidth can approach one-half of the input frequency while maintaining stability.

To full this gap, this paper proposes a multi-inverter parallel microgrid stability analysis method based on PLL. Firstly, this paper establishes a PLL small signal model based on the droop control strategy and the P&Q control strategy.

Abstract—This paper presents a generalization of the classical phase-locked loop (PLL) theory. It includes the effects of time-delays and mutual coupling between PLLs. Two methods for finding stable solutions to locked states and their transient dynamics are discussed.

2021年12月1日 · A new form of the Popov based frequency domain criterion is derived in which the size of the stability region, the PLL locking range, appears independently of the loop transfer-function. This enables one to maximize the stability region graphically and directly on the Popov plot, rather than iteratively.

Understanding PLL Frequency Response • Frequency domain analysis can tell us how well the PLL tracks the input phase as it changes at a certain frequency • PLL transfer function is different depending on which point in the loop the output is responding to 12 Input phase response VCO output phase response f out in f out vco

2020年1月1日 · For the classical analog PLL, stability of the locked state depends on the gap between the VCO free-running frequency and the frequency of the ref- erence signal. For active proportionally-integrating (PI) filter, analog PLL is theoretically stable for any gap.