Mechanical sensorless control of a rotor-tied DFIG wind energy conversion system using a high gain observer

Abstract

This paper proposes a field-oriented control (FOC) of a rotor-tied DFIG (RT-DFIG) using a high gain observer (HGO). For speed/DC-voltage and current regulation, the FOC employs a Proportional-Integral (PI) controller in both outer and inner loops. The goal is to maximize wind power mining by allowing wind turbines to operate at variable speeds. In addition, by utilizing current/voltage measurements, HGO estimates the mechanical speed of the rotor for FOC deployment. Finally, the simulation results of the suggested method for the 7.5 kW RT-DFIG are provided. The HGO was tested in both static and dynamic wind settings and with parameter modifications. Furthermore, various existing observer-based control methods were compared, which verified the proposed method’s superiority.

Keywords

• Wind energy conversion system
• Doubly fed induction generator
• Rotor-tied DFIG
• Mechanical sensorless control
• High gain observer