Precision control of single-phase PWM inverter using PLL compensation

Phase-Locked Loops using State Variable Feedback for Single-Phase Converter Systems

“…2 and described by (3); instead of a filter to attenuate the 2ω ripple in steady-state, this method essentially forces V err to zero during phase-lock conditions. Expanded out, (4) is obtained; if A ≈ 1, then (5) shows that zero steadystate error occurs and the 2ω term is only present during synchronization transients (ψ ≠ 0).…”

“…N grid connected systems, a critical component of the converter's control system is the phase-locked loop (PLL) that generates the grid voltage's frequency and phase angle for the control to synchronize the output to [1][2][3][4][5][6]. Estimated frequency, ω e , and phase angle, θ e , of the grid voltage by the PLL can be used not only for control and signal generation, through synthesis or transformations, but also in protection to detect when the converter has entered an islanded mode.…”

“…A control system's PLL operating based on this grid voltage measurement must be designed to be able to phaselock quickly, accurately and produce low distortion outputs under all imaginable grid conditions [1,5,[7][8][9]. As such, PLL systems that can synchronize to these grid parameters accurately and as quickly as possible are of vital importance; otherwise, inaccurate and potentially harmful control of power factor angle, harmonics, and the determination of system mode of operation can result [10][11][12].…”

A high-performance single-phase Phase-Locked-Loop with fast line-voltage amplitude tracking

“…crucial component of the single-phase (1Φ) system is the PLL that tracks the grid voltage's frequency and phase angle [1][2][3]. Therefore, accurate, fast responding PLLs for control and protection purposes are required to provide these measurements.…”

“…2, a typical PLL system is composed of the phase-detector (PD), loop-filter (LF), and digital-controlled oscillator (DCO) [3,10]. Generally, PLLs vary widely from one another in the design and implementation of the phase detector.…”