Investigation on the impact of design wind speed and control strategy on the performance of fixed-pitch variable-speed wind turbines

This paper studies the operation of wind turbines in terms of three phases: start-up phase, power-generation phase, and shutdown phase. Relationships between the operational phase and control rules for the speed of rotation are derived for each of these phases. Taking into account the characteristics of the control strategies in the different operational phases, a global control strategy is designed to ensure the stable operation of the wind turbine in all phases. The results of simulations are presented that indicate that the proposed algorithm can control the individual phases when considered in isolation and also when they are considered in combination. Thus, a global control strategy for a wind turbine that is based on a single algorithm is presented which could have significant implications on the control and use of wind turbines.

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Design of advanced airfoil for stall-regulated wind turbines

Wind Energy Science ◽

10.5194/wes-2-403-2017 ◽

2017 ◽

Vol 2 (2) ◽

pp. 403-413

Author(s):

Francesco Grasso ◽

Domenico Coiro ◽

Nadia Bizzarrini ◽

Giuseppe Calise

Keyword(s):

Wind Turbines ◽

Design Strategy ◽

High Wind ◽

Pitch Control ◽

Turbine Performance ◽

Gradient Based ◽

Machine Control ◽

And Control ◽

The Impact ◽

Numerical Optimisation

Abstract. Nowadays, all the modern megawatt-class wind turbines make use of pitch control to optimise the rotor performance and control the turbine. However, for kilowatt-range machines, stall-regulated solutions are still attractive and largely used for their simplicity and robustness. In the design phase, the aerodynamics plays a crucial role, especially concerning the selection/design of the necessary airfoils. This is because the airfoil performance is supposed to guarantee high wind turbine performance but also the necessary machine control capabilities. In the present work, the design of a new airfoil dedicated to stall machines is discussed. The design strategy makes use of a numerical optimisation scheme, where a gradient-based algorithm is coupled with the RFOIL code and an original Bezier-curves-based parameterisation to describe the airfoil shape. The performances of the new airfoil are compared in free- and fixed-transition conditions. In addition, the performance of the rotor is analysed, comparing the impact of the new geometry with alternative candidates. The results show that the new airfoil offers better performance and control than existing candidates do.

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The impact of implementing HIV prevention policies therapy and control strategy among HIV and AIDS incidence cases in Malaysia

Infectious Disease Modelling ◽

10.1016/j.idm.2020.09.009 ◽

2020 ◽

Vol 5 ◽

pp. 755-765

Author(s):

Ofosuhene O. Apenteng ◽

Prince P. Osei ◽

Bismark Oduro ◽

Mavis Pearl Kwabla ◽

Noor Azina Ismail

Keyword(s):

Hiv Prevention ◽

Control Strategy ◽

Hiv And Aids ◽

Prevention Policies ◽

And Control ◽

The Impact

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