Performance analysis of 1ϕ T/4 PLLs with secondary control path in current sensorless bridgeless PFCs

Abstract

New power factor correction (PFC) stages such as bridgeless converters and the associated current shaping techniques require grid synchronization to ensure unity Displacement Power Factor (DPF). Sensorless line current rebuilding algorithms also need synchronization with the line voltage to compensate at least for part of the current estimation error. The application of a secondary control path to reach faster and more robustly the proper operation point previously applied in single/three-phase PLLs in grid connected converters is here proposed for the current sensorless bridgeless PFCs. This work analyzes the performance of three single-phase T/4 PLL structures, first without secondary control path, and later with feedforward and feedback secondary control paths, both in simulation and experimentally, and evaluates their applicability to current sensorless digitally controlled single phase bridgeless PFCs based on the current rebuilding technique.

1phi SOGI Phase Locked Loop with Secondary Control Path in Grid-Connected Power Converters

“…The steady-state test consists of a combination of harmonically distorted grid voltages -odd orders in [3,7], relative phases in [0,2π) rad, relative amplitudes in [0, 0.05] pu-, accomplishing the allowable levels in IEEE 519-2014 [16], and grid frequencies in [49,51] Hz. The obtained probability density functions (PDFs) for both average and peak-to-peak values of phase error, θe, are compared in Figs.…”

“…Secondary control paths (SCP) have been used in some PLLs [13]- [16] to improve their dynamics. The approach with SCP is adjusting the loop filter gains to change the dynamics depending on the error signal.…”

“…1.c, which consists of a frequency feedback (FFB) loop applied to the PI controller of the PLL. The FFB loop, selected as SCP in [16], adjusts the proportional gain of the PI controller depending on its output, which speeds up the controller in the case of frequency variations. More details about the selection of KFFB are found in [16].…”

PFC Single-Phase AC/DC Boost Converters: Bridge, Semi-Bridgeless, and Bridgeless Topologies

“…Additionally, this topology has the potential capacity for bidirectional power conversion. Nevertheless, its inherent asymmetry increases the complexity of the controller and requires isolation in each driver of the branches [41][42][43].…”

Synchronous Rectifier for High-Frequency Switch-Mode Power Supplies Using Phase-Locked Loops

“…PLLs are widely applied in telecommunications field as frequency generation sources, as well as for pulse-width-modulation in power amplifiers [19], [20]. PLLs have been introduced in grid-connected converters, to optimize grid synchronization [21], [22]. Very few works have used PLLs in RF-SMPSs.…”