This paper presents an improved control strategy for both the rotor side converter (RSC) and grid side converter (GSC) of a doubly fed induction generator (DFIG)-based wind turbine (WT) system to enhance the low voltage ride through (LVRT) capability. Within the proposed control strategy, the RSC control introduces transient feed-forward compensation terms to mitigate the high frequency harmoni...

With the rapid increase in proportion of installed wind power capacity total grid capacity, state has put forward higher and requirements for integration into grid, among which most difficult requirement is zero-voltage ride through (ZVRT) capability turbine. When voltage drops deeply, a series transient processes, such as serious overvoltage, overcurrent, or speed rise, will occur motor, serio...

In Isolated power systems the power quality problem is compounded as the drive converter loads are likely to fluctuate in conjunction with mining or exploration areas. The use of compensators in improving power quality of isolated power systems is considered. The roles of the compensators are to mitigate the effects of momentary voltage sags/swells, and to control the level of harmonic distorti...

Abstract With the number of wind farms connected to power system increasing rapidly, impact generation on grid stability is becoming increasingly prominent. Especially when has transient fault, there will be problems such as reverse flow, large-area failure farm and so on. This directly lead instability seriously affect security stability. in stage voltage recovery after fault eliminated, low-v...

Voltage sags normally do not cause equipment damage but can easily disrupt the operation of sensitive loads such as electronic Adjustable Speed Drives (ASD’s). Voltage sags cause a momentary decrease in DC-link voltage triggering an under voltage trip leading to nuisance tripping of adjustable speed drives (ASD’s) employed in continuous-process industries which contributes to loss in revenue. A...

This paper presents SCR-based circuit extensions to a diode rectifier to allow regeneration during braking and ride-through during voltage sags. The proposed topology uses two line-commutated SCR bridges – one connected to the dc bus rails and the other to the dc bus center-tap. The inverting SCR bridge connected to the dc bus rails transfers energy from the dc link to the mains during regenera...

in this paper, plug-in fuel cell electric vehicle (pfcev) is considered with dual power sources including fuel cell (fc) and battery energy storage. in order to respond to a transient power demand, usually supercapacitor energy storage device is combined with fuel cell to create a hybrid system with high energy density of fuel cell and the high power density of battery. in order to simulate the...

This thesis deals with the analysis, modeling, and control of the doubly-fed induction generator (DFIG) for wind turbines. Different rotor current control methods are investigated with the objective of eliminating the influence of the back electromotive force (EMF), which is that of, in control terminology, a load disturbance, on the rotor current. It is found that the method that utilizes both...