Compensation method of phase-locked loop under unbalanced grid condition based on harmonic linearization

2018 ◽  
Vol 46 (6) ◽  
pp. 1181-1203
Author(s):  
Xiaoming Zha ◽  
Yang Cen ◽  
Meng Huang ◽  
Dongdong Peng
Keyword(s):  
Phase Locked Loop ◽  
Compensation Method ◽  
Harmonic Linearization ◽  
Unbalanced Grid

scholarly journals A phase-locked loop using ESO-based loop filter for grid-connected converter: performance analysis

2021 ◽  
Author(s):  
Baoling Guo ◽  
Seddik Bacha ◽  
Mazen Alamir ◽  
Julien Pouget
Keyword(s):  
Performance Analysis ◽  
Frequency Domain ◽  
Low Frequency ◽  
Experimental Tests ◽  
Frequency Measurement ◽  
Phase Locked Loop ◽  
Frequency Domain Analysis ◽  
Loop Filter ◽  
Control Stability ◽  
Unbalanced Grid

AbstractAn extended state observer (ESO)-based loop filter is designed for the phase-locked loop (PLL) involved in a disturbed grid-connected converter (GcC). This ESO-based design enhances the performances and robustness of the PLL, and, therefore, improves control performances of the disturbed GcCs. Besides, the ESO-based LF can be applied to PLLs with extra filters for abnormal grid conditions. The unbalanced grid is particularly taken into account for the performance analysis. A tuning approach based on the well-designed PI controller is discussed, which results in a fair comparison with conventional PI-type PLLs. The frequency domain properties are quantitatively analysed with respect to the control stability and the noises rejection. The frequency domain analysis and simulation results suggest that the performances of the generated ESO-based controllers are comparable to those of the PI control at low frequency, while have better ability to attenuate high-frequency measurement noises. The phase margin decreases slightly, but remains acceptable. Finally, experimental tests are conducted with a hybrid power hardware-in-the-loop benchmark, in which balanced/unbalanced cases are both explored. The obtained results prove the effectiveness of ESO-based PLLs when applied to the disturbed GcC.

PR Control of a Three-Phase Grid-Connected Inverter under Unbalanced Grid Voltages Condition

2015 ◽  
Vol 713-715 ◽  
pp. 1019-1022
Author(s):  
Kun Liu ◽  
Zhen Xie
Keyword(s):  
Theoretical Analysis ◽  
Phase Locked Loop ◽  
Experimental Results ◽  
Effective Control ◽  
Experimental Platform ◽  
Fast Phase ◽  
Three Phase ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
Unbalanced Grid

The effective control of a grid-connected inverter (GCI) under unbalanced grid voltages condition is able to enhance the grid-connected operation ability of the inverter. This paper studies the control scheme of a three-phase GCI with proportional plus resonant (PR) regulators in the stationary αβ frame to remove the power ripples caused by the unbalanced condition and the currents of positive and negative components can be controlled directly without any decomposition. A precise and fast phase locked loop is also introduced in this paper. Three control targets are achieved on a 2KVA experimental platform of a GCI and the experimental results agree well with the theoretical analysis.

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