An LVRT Scheme for Grid Connected DFIG Based WECS Using State Feedback Linearization Control Technique

Abstract

This paper primarily focuses on an advance control strategy to enhance the low voltage ride through (LVRT) capability in doubly fed induction generator (DFIG) based wind energy conversion system (WCES). In the proposed control strategy, the captured wind energy during grid faults circumstances is stored timidly in the rotor’s inertia kinetic energy. Though a minimal amount of energy is available in the grid, stator current and DC-link voltage are set beneath the perilous levels. However, both the required stator voltage and stator current are kept within a tolerable range of rotor side converter (RSC), through state feedback linearization technique for maintaining the accurate control to suppress the overvoltage and overcurrent. Furthermore, stator current oscillations are significantly suppressed during fault transient. The input mechanical energy from the wind turbine can be resumed after the fault clearance. In spite of being dissipated in the resistors of crowbar circuit, as in the conventional LVRT assemblies, torque balancing among electrical and mechanical measures is attained; DC-link voltage instabilities and rotor speed inconsistencies are substantially reduced. As a result, a noticeable reduction in the requirement of reactive power and swift restoration of terminal voltage on fault clearance is acquired successfully. Correspondingly, several tests are conducted to validate the effectiveness and enhancement in the performance of the DFIG based wind farms, when the proposed control strategy is implemented over it during numerous fault ride-through circumstances.

Low-Voltage Ride-Through Techniques in DFIG-Based Wind Turbines: A Review

“…There are other two feedforward control methods that improve the transient capability of DFIG-WTs by adding feedforward terms: (1) feedforward current reference control (FCRC) was proposed to achieve zero-error tracking for the rotor current references after grid faults. By introducing the additional rotor current feedforward to the current loop, the rotor current can be maintained in a balanced and sinusoidal manner [71]; (2) feed-forward transient current control (FFTCC) was proposed to reduce transient current stress on the RSC and ensure that the active and reactive power supply remains uninterrupted by adding the stator flux-related feedforward components to the current loop [72].…”

“…In recent years, renewable energy generation made great progress worldwide to meet the challenge of drastic climate changes and increasing energy demands [1]. Among various renewable energy sources, wind energy is the most rapidly growing one around the world [2,3]. In 2018, the 51.3 GW of new installations brought total cumulative installations of wind power up to 591 GW, and the Global Wind Energy Council (GWEC) expects that more than 55 GW of new capacity will be added each year until 2023.…”

A Robust Interval Type-2 Fuzzy Logic Controller for Variable Speed Wind Turbines Based on a Doubly Fed Induction Generator

“…Conventional proportional-integral (PI) controllers are the most commonly used in the control strategy of wind energy conversion system due to their simple implementation and deliver a good performance under normal conditions. However, under challenging operating conditions such as parameter variations, and the wind disturbance effect, the control strategies based on the PI controller do not give a satisfactory performance in terms of accuracy [8].…”

Control of a Variable-Impedance Fault Current Limiter to Assist Low-Voltage Ride-Through of Doubly Fed Induction Generators

“…A comprehensive review on the power transmission technology involved in offshore wind farms was carried out in [5], where the capabilities of WTGs to realize LVRT and support the system frequency through the active power control were introduced in detail. The LVRT capability is a major concern in the fault scenarios of wind power systems [6,7]. To assist the LVRT of the DFIG, both software control schemes and hardware protection schemes have been developed [8].…”