Coupling Influence on the dq Impedance Stability Analysis for the Three-Phase Grid-Connected Inverter

Chuanyue Li (1) , Taoufik Qoria (1) , Frederic Colas (1) , Liang Jun (2) , Ming Wenlong (2) , Francois Gruson (1) , X. Guillaud (1)

1 L2EP - Laboratoire d’Électrotechnique et d’Électronique de Puissance - ULR 2697
2 School of Engineering [Cardiff]

The dq impedance stability analysis for a grid-connected current-control inverter is based on the impedance ratio matrix. However, the coupled matrix brings difficulties in deriving its eigenvalues for the analysis based on the general Nyquist criterion. If the couplings are ignored for simplification, unacceptable errors will be present in the analysis. In this paper, the influence of the couplings on the dq impedance stability analysis is studied. To take the couplings into account simply, the determinant-based impedance stability analysis is used. The mechanism between the determinant of the impedance-ratio matrix and the inverter stability is unveiled. Compared to the eigenvalues-based analysis, only one determinant rather than two eigenvalue s-function is required for the stability analysis. One Nyquist plot or pole map can be applied to the determinant to check the right-half-plane poles. The accuracy of the determinant-based stability analysis is also checked by comparing with the state-space stability analysis method. For the stability analysis, the coupling influence on the current control, the phase-locked loop, and the grid impedance are studied. The errors can be 10% in the stability analysis if the couplings are ignored.

Mots clés: impedance stability analysis; VSC; small-signal modelling

Domaines: Sciences de l'environnement

Chuanyue Li, Taoufik Qoria, Frederic Colas, Liang Jun, Ming Wenlong, et al.. Coupling Influence on the dq Impedance Stability Analysis for the Three-Phase Grid-Connected Inverter. Energies, 2019, pp.16. ⟨hal-02308368⟩