Novel three phase locked loop technique based on double Park transformation
LI Yan-da
Abstract：Aiming at the problem that the double frequency harmonic perturbation exists in the output of three phase locked loop (PLL) when the power grid voltage has unbalanced fault, a novel PLL based on the double Park transformation was proposed.The positive and negative sequence Park transformation for the voltage signal was carried out, respectively.In addition, the DC component in the negative sequence Park transformation was multiplied by the transformation matrix, and the double frequency component in the positive sequence Park transformation could be eliminated through the cross decoupling.The fundamental positive DC component was effectively extracted, and the accurate tracking of phase and frequency could be realized under the unbalanced grid voltage condition.A simulation model was established in the Matlab/Simulink environment, and the steady state response of PLL under the unbalanced grid voltage was analyzed.The results show that compared with the traditional PLL, the proposed PLL can detect the voltage phase and frequency information more accurately under the grid fault.
Keywords：phase locked loop (PLL)three-phase unbalancedouble-frequencydouble Parkpositive and negative sequence componentDC componentcross decoupling
Publication Date：2017-05-02
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 253-257 )