Dual‐loop control of transfer delay based PLL for fast dynamics in single‐phase AC power systems

Abstract

Phase-locked loop (PLL) is commonly utilised for AC power systems to detect phase and frequency. With the increasing use of small-scale distributed power generation, the technique becomes widely available for grid interconnection of renewable power source into single-phase AC distribution network. Through comprehensive analysis and design, this study proposed a new approach that includes dual independent control loops to enhance the transfer delay-based PLL capability in terms of speed and accuracy. The effectiveness and advantages of the proposed PLL structure are demonstrated by numerical simulation and verified by experimental test.

Development of Frequency-Fixed All-Pass Filter-Based Single-Phase Phase-Locked Loop

“…The idea is to generate an equal and opposite error in the first term by placing another nonadaptive APF block for indirect generation of the cosine of the estimated angle. This method is inspired from the nonfrequency dependent time delay PLL (NTD-PLL) [33] and here labelled as modified transformation APF (MTAPF).…”

Pre‐filter phase‐locked loop: principles and effects with inter‐harmonic perturbation

“…Since Δθ is tiny, (9) can be approximated as (10) Assume that there is a transfer function F(s) between Δθ and voltage perturbation, which can be written as…”

“…Besides, as the conventional PLL could not satisfy application requirements for some situation perfectly, complex structures or methods of PLL are developed [10]. In [11], a new tuning method for the SRF-PLL is proposed which quantifies the tradeoff between the unit vector total harmonic distortion (THD) and the bandwidth of the SRF-PLL.…”

Analysis and improvement of fourth‐order generalised integrator based phase‐locked loop

“…The synchronous reference frame (SRF) phase-locked loop (PLL), which is a typical nonlinear closed loop feedback system, may be the most popular method for this purpose. The SRF-PLL usually includes three parts: a phase detector, a loop filter and a voltage-controlled oscillator [4,5]. Generally, single-phase PLLs are more complicated to design than three-phase PLLs [6].…”

“…The orthogonal signals can be easily obtained through Park's or Clark's transformation of three-phase voltage [3]. In a single-phase system, there is only the information of one-phase voltage, and a fictitious quadrature signal needs to be constructed through a quadrature signal generator (QSG) [5][6][7][8]. There are many methods to achieve this goal, such as the transfer delay (TD) [6], all pass filter (APF) [7,9], Hilbert transformers (HT) [10][11][12], derivative term (DT) [13], inverse Park's transformation (IPT) [2,14], second-order generalised integrator (SOGI) [15][16][17][18][19][20], etc.…”