Distributed Torque Control of Deloaded Wind DFIGs for Wind Farm Power Output Regulation

In this work, we propose a distributed control methodology that solves the problem of dispatching and regulating the power outputs of a group of deloaded wind double-fed induction generators (DFIGs) to attain fast, dynamic, and efficient wind farm power output regulation, with fair load-sharing among the DFIGs. In this context, fair load-sharing means that the ratio defined by the mechanical power over the maximum power from the wind, i.e., the utilization level, of all DFIGs, is the same in the steady state. Dynamic distributed dispatch and control of the power outputs of DFIGs refers to their ability to self-dispatch and regulate their power outputs under dynamical conditions and through peer-to-peer information exchange. Initially, we propose a leader-follower consensus protocol that DFIGs can adopt into their control system to attain: 1) asymptotic consensus on their utilization levels (i.e., fair load-sharing), and 2) total power output regulation. Then, we perform compositional stability analysis and prove that the protocol asymptotically converges under sufficient conditions. Finally, we design a distributed control-Lyapunov-function-based torque controller for the rotor-side converter that realizes the protocol in practice. The performance of the distributed control methodology is evaluated through numerical simulations on the modified IEEE 24-bus RT system.