Frequency-adaptive Virtual Flux Estimation for Grid Synchronization under Unbalanced Conditions
Location: USA
Publication date: 2010-11-08
Published in: Annual Conference of the IEEE Industrial Electronics Society 2010, Phoenix (USA) - IECON 2010
ref. DOI: 10.1109/IECON.2010.5674924

Local members

Alvaro Luna

PhD. Senior Researcher.

External members

Suul, J. , Undeland, T.



This paper proposes a new and explicitly frequency-adaptive method for Virtual Flux estimationand voltage sensor-less grid synchronization under unbalanced conditions. The proposed system is based on using Second Order Generalized Integrators, arranged to simultaneously fulfill the purposes of frequency-adaptive band-pass filtering, integration and quadrature signal generation. This results in a simple and efficient structure for combined Virtual Flux estimationand separation into positive and negative sequence components. The properties of the proposed Virtual Flux model is analyzed theoretically, first as an integrator for implementing generic Virtual Flux estimation, and then with respect to sequence separation. The dynamic performance of the proposed estimation method is tested by simulations for the case of anunbalanced voltage drop in the grid and for a step in grid frequency. The simulations verify the performance to be as expected, with similar dynamics as synchronization based on voltage measurements.


Associated projects

National public