  Active power control regulates the total power generated by wind farms with
the power consumed on the electricity grid. Due to wake effects, the available
power is reduced and turbulence is increased at downstream wind turbines. Such
effects lead to a design challenge for wind farm control, where the delicate
balance between supply and demand should be maintained, while considering the
load balancing in the wind turbine structures. We propose a control
architecture based on simple feedback controllers that adjusts the demanded
power set points of individual wind turbines to compensate for turbine
saturations and to balance thrust forces. For compensation purposes, the
dynamics of power tracking in the wind turbines is approximated as a pure
time-delay process, and the thrust force balance design is based on an
identified linear model of the turbines. In this paper, we show that the
proposed control architecture allows the generated power to track its reference
even when turbines saturate, while the thrust forces are balanced. In addition,
the result shows that the proposed power dispatch strategy, which considers
thrust force balance, also avoids turbine saturation, being thus beneficial for
energy production. The effectiveness of the proposed feedback controller is
demonstrated using high-fidelity computational fluid dynamics simulations of a
small wind farm.
