A Review on PV- Doubly Fed Induction Generator Wind Turbine Technology

Authors: Surendra Kumar Chourasiya, Professor. Vinay Pathak

Certificate: View Certificate

Abstract

Wind energy conversion system is becoming very popular now a days and the application of wound rotor induction machine is widely spread in wind energy generating stations because of its adaptability for variable speed wind turbines through which maximum possible extraction of wind energy is possible. Also among all the induction generator configurations for wind power systems the use of Doubly Fed Induction Generator (DFIG) configuration with back to back pulse width modulated voltage source converters (VSC) is one of the best topologies available and it is suitable for both grid connected systems as well as stand-alone systems. In this paper, a brief review of all the control strategies for both stator side converter and rotor side converter are discussed in stator flux oriented reference frame and results are compared on the basis of cost, efficiency , power consumption and harmonics

Introduction

The rising demand for electricity and the scarcity of fossil fuel has intended to enhance the utilization of renewable energy sources for both economic and environmental benefits. WECS is regarded as a bulk supplier of electric power to power grids and wind power production is growing rapidly day by day. As indicated by the Global Wind Energy According to the orientation of wind turbines (WT), it is classified into two types i.e. horizontal axis wind turbine (HAWT) and vertical axis wind turbine (VAWT). The HAWT with variable speed mode is the most convenient and commonly used WTs. The WT is able to extract more energy by adjusting the rotor speed. Such flexible wind speed operation also reduces drive train mechanical stress and smoothes output power. In a WECS after the WT the wind energy is converted to electrical energy through an optional gearbox and a generator attached with it. Doubly-fed induction generator (DFIG) and permanent magnet synchronous generator (PMSG) are predominant types of generator though other types of the generator have also been used. In today’s competitive energy market the implementation of simple, reliable, efficient and cost-effective WECS is highly recognizable. But the nonlinear aerodynamic system, the mechanical complexity in the system, the presence of different kinds of faults make the operation of WECS more complicated. For the safety of WECS many efficient control strategies such as supervisory control for the startup and shut down of WT, blade pitch angle control, generator torque control, yaw control, internal generator control, power electronics devices control, pitch actuator control, fault-tolerant control etc. are implemented. Also, IEEE Standard 519–20142 requires that WECS must stand with the grid for a temporary overvoltage at the grid interconnection. Numerous research works are going on based on new control strategies for the improvement in the operation of WECS. Many researchers have contributed reviews with a focus on different aspects of the WECS. As the effect of WECS in large rating has a sizable impact on the grid, the gridconnected systems with WECS are the circle of research.

Conclusion

In this paper, various methods for analyzing DFIG wind turbines impact on power system dynamic performance, such as frequency stability, transient stability, small-signal stability, and voltage stability, have been reviewed. Advanced control techniques of the DFIG for grid service supports, i.e. frequency control, voltage control, and power oscillation damping, have been described. The results and future trend can be summarized as follows. The replacement of synchronous generators by DFIG wind turbines not only reduces the effective system inertia but also aggravates the synchronizing torques. This mainly affects the power system\'s dynamic performances. Nevertheless, the controllable output power of DFIG wind turbines with appropriate control can be utilized to ameliorate the power grid dynamics. Regarding the impact on frequency stability, DFIG wind farms not merely worsen the frequency nadir but also expedite the ROCOF. To alleviate both problems, the hidden inertia of DFIGs can be extracted by inertial control. The key point of this control is how to adapt the controller gains so that more kinetic energy stored in the DFIG rotor can be released. Improved inertial control methods that can inject more kinetic energy and guarantee stable operation are significantly required.