Control strategy for variable-speed, stall-regulated wind turbines

Abstract

NOTICEThis report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercialproduct, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authord expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. ABSTRACTA variable-speed, constant-pitch wind turbine was investigated to evaluate the feasibility of constraining its rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracted by the blades from the wind was manipulated. Specifically, the blades were caused to stall in high winds. In low and moderate winds, the demanded generator torque and the resulting rotor speed were controlled to cause the wind turbine to operate near maximum efficiency. A computational model was developed, and simulations were conducted of operation in high turbulent winds. Results indicated that rotor speed and power output were well regulated.

Performances and Stall Delays of Three Dimensional Wind Turbine Blade Plate-Models with Helicopter-Like Propeller Blade Tips

“…Bang et al have made comparison between new active speed stall control and pitch control for a direct-drive wind turbine with different actuation methods (Bang & Polinder, 2007). A conservative control strategy for variable-speed, stall-regulated wind turbines have also been investigated (Muljadi, Pierce, & Migliore, 1998 …”

Wind driven mobile charging of automobile battery- A case study

“…The 24V generator used in this system is Permanent Magnet Synchronous Generator (PMSG) (Muljadi, et al, 1998). The term permanent magnet machine is used to include all electromagnetic energy conversion devices in which the magnetic excitation is supplied by a permanent magnet.…”

Non-linear control of variable-speed wind turbines with permanent magnet synchronous generators: a robust backstepping approach

“…As stated in Müller, Deicke, and De Doncker (2002), variable-speed wind turbines are more advantageous, as they increase energy capture, has the ability to operate at maximum power point, improve efficiency and has power quality. The quality of power generation (and output regulation) strongly depend on the control technique employed (Muldaji, Pierce, and Migliore 1998), that is, the effectiveness of the wind power generation relies mostly on the control strategy. Therefore, for variable-speed wind turbines, the wind power is truly cost effective via the use of advanced control techniques, such as model-based control design approaches.…”

“…To overcome the aforementioned problems, a vast number of control strategies have been proposed for variable-speed wind turbines. In Muldaji et al (1998), authors have evaluated a variable-speed, stall-regulated strategy that eliminates the need for ancillary aerodynamic control systems. In Boukhezzar and Siguerdidjane (2005), a cascade structure, non-linear controller was proposed; however, parametric uncertainties of the system were not taken into account.…”