Development of Grid –Connected Renewable Generation Control Techniques

This article develops and presents a comparative analysis of two types of wind energy conversion system (WECS), which are the doubly fed induction generator (DFIG)-based WECS incorporating a voltage source converter (VSC) with a proportional-integral (PI) controller and the DFIG based WECS incorporating a VSC with a Proportional Integral Derivative (PID) controller. The parameters for comparison include: the steady-state error, the percentage overshoot and undershoot, the damping oscillations and the settling time of the voltage/current or power output signals and dc-link voltage signal. The VSC is selected as compared to the line commutated converters (LCCs) because of the commutation that is not dependent on voltage and current AC signals. The grid-side converter is applied to regulate dc-link voltage and reactive power to their reference values. Furthermore, the rotor side converter provides rotor speed regulation on the DFIG to maintain the active power output. The vector control strategy is utilized to achieve sufficient control of the system. The control system is modelled using MATLAB/SIMULINK. From the simulation results, it is found that the DFIG based WECs incorporating a PID controller performed efficiently compared to DFIG based WECs incorporating a PI controller.