Adaptive Virtual Inertia Controller for DFIGs Considering Nonlinear Aerodynamic Efficiency

With increasing the share of renewable energy sources (RESs) in the power systems, the frequency stability becomes a crucial concern. This issue can be handled with some auxiliary frequency controllers which use the kinetic energy of blades of the variable speed wind turbines (VSWTs). This paper focuses on the deficiencies of conventional virtual inertia controller (VIC). Efficiency decrement of VSWT during severe contingencies is one of the main deficiencies of conventional VICs. In this study, its impacts on the performance of conventional VICs are first determined using some sensitivity analyses. An adaptive VIC is then proposed to overcome this issue. The designed VIC controller not only reduces the impacts of VSWT's efficiency decrement on the frequency stability, but also improves the performance of VIC due to its adaptation property. To achieve optimal performance, the parameters of proposed VIC are tuned using a multi objective optimization problem. Some time domain simulations are performed on an IEEE 9-bus test system to investigate the performance of proposed VIC. Results confirm a more reliable operation of the power systems in which the VSWTs are equipped with the proposed VIC.