Optimized Control for PMSG Wind Turbine Systems under Unbalanced and Distorted Grid Voltage Scenarios

Abstract

Wind energy is one of the fastest growing energies due to its feasible cost and environment friendly nature, where there is no emission of waste or greenhouse gases emission. Wind energy systems should be connected to the electric utility to avoid the effects of the intermittent nature of these sources. One of the main problems of the utility integration of wind turbines is the unbalanced voltage of the utility grid. Many efforts have been made to remedy the effects of the unbalanced grid voltage connected with the electric utility. This research points out the need for more accurate and robust controllers, such as those mentioned in this paper. A novel combination strategy is presented in this paper to overcome the inherent imbalance in the electric utility voltages when used in combination with a permanent magnet synchronous generator (PMSG). This novel technique is designed to adapt the positive sequence of the dq-axis of the output current from the PMSG to extract the maximum power available from a wind turbine. Meanwhile, the negative sequence component is used to improve the quality of the output current from a wind turbine. A current controller is introduced in the grid side converter to compensate for the effects of the 2nd and 6th components of the output currents. Using these controllers reduces all dominant components in the output currents from wind turbines and permits a robust tracker for the maximum power available. A detailed simulation and experimental studies are introduced in this paper to show the controller operation under different operating conditions. The simulation and experimental results from the novel proposed strategy show its superiority in fully remedying the effect of unbalanced grid voltages.