Hybrid controller for transient stability in wind generators

Abstract

In wind power plants typically squirrel-cage induction generators (SCIG) tend to drain large amount of reactive power from the grid, potentially causing a drop voltage. To improve SCIG's power quality and transient stability, this paper investigates a new pitch angle control strategy, including normal scheme and Fault-Ride-Through (FRT) scheme, based on hybrid of PI and Fuzzy logic technique. In particular, an analytic model for transient stability is implemented using the equivalent circuit of the SCIG and on the concepts of stable and unstable electrical-mechanical equilibrium. This method has been evaluated by comparing the results with the dynamic simulation. The dynamic simulation results show that the proposed hybrid controller can be effective in enhancing output power smoothness and FRT requirements for SCIG in wind power system

Complying the LVRT grid code requirement of a fixed speed wind energy system using unified voltage and pitch angle control strategy

“…But, PI controller is not a good choice in fault-ride-through (FRT) scheme of pitch-angle control loop, as the controller is required to generate a desired pitch-angle command ( β FRT ) so that the mechanical power can be reduced in a very efficient manner to limit rotor speed. Therefore, fuzzy logic controller (type-1) is the best choice for FRT scheme of pitch-angle controller (Duong et al, 2015). However, once the membership functions are defined for designing the controller, the uncertainties in membership functions (MFs) cannot be incorporated, thereafter (Hagras and Wagner, 2012; Mendel, 1999).…”

“…In addition, it can also improve the transient stability of the wind generator by reducing the mechanical torque with suitable pitch angle generation (Muyeen et al, 2009). Many researchers have carried out their work on transient stability enhancement of wind energy system using pitch angle controller (Duong et al, 2015;Muyeen et al, 2006;Shima et al, 2008;Tamura, 2001;Thet and Saitoh, 2009).…”

Capacity Credit Evaluation of Correlated Wind Resources Using Vine Copula and Improved Importance Sampling

“…Clean energy resources such as renewable energy sources and flexible demand have been introduced into power systems in order to establish an environment-friendly society [1][2][3][4]. Wind energy, a kind of clean energy, has experienced rapid development in recent years to aid lowering of greenhouse gas emission [5,6]. However, wind farms cannot provide a steady power capacity, restricting the current power system from transitioning to one with high penetration of wind energy [7].…”

Advanced Type-2 fuzzy logic–based pitch-angle control strategy for wind energy system

“…In some previous works (Al-Saffar and Musilek, 2016;Garasi et al, 2014;Kadri and Khan, 2012;Konara and Kolhe, 2015;Mi et al, 2014aMi et al, , 2014bPoultangari et al, 2012;Sakamoto et al, 2006;Vega et al, 2015), different methods have been proposed to design the pitch control system to regulate the output power at rated level and improve the output power quality with frequent wind speed changes. Beside this, pitch-angle controller is also employed to stabilize the WES using pitch-angle controller for transient faults (Duong et al, 2015). It is important to carry the transient stability analysis to investigate the impact of WES on utility grid.…”

“…None of them (Al-Saffar and Musilek, 2016;Anderson and Bose, 1983;Garasi et al, 2014;Kadri and Khan, 2012;Konara and Kolhe, 2015;Mi et al, 2014aMi et al, , 2014bMuyeen et al, 2006;Poultangari et al, 2012;Sakamoto et al, 2006;Shima et al, 2008;Tamura, 2001;Vega et al, 2015;Wasynczuk et al, 1981) investigated the pitch-angle controller for both purpose (to maintain the power output to its rated value for above rated wind speed and transient stability investigation during network faults). Therefore, Muyeen et al (2005Muyeen et al ( , 2009 and Duong et al (2015) have designed pitch-angle control strategy to improve the power quality and transient stability enhancement in power and speed control modes, respectively, using traditional fuzzy logic controller (called as Type-1 fuzzy logic controller (FLC)). Fuzzy logic-based pitch-angle controller is best suited as it provides improved performance in tracking reference in comparison to other controllers.…”