Genetic algorithm optimization of PID pitch angle controller for a 2 MW wind turbine

Speed regulation of wind turbine rotors are controlled by pitch angle controllers that aect the life expectancy of wind turbines, reliability and power quality. Optimization of wind turbine pitch angle controllers perform crucial eect on the wind turbine dynamics where the speed stability is achieved. In today's modern and commercial wind turbines, blade pitch angle controllers are generally implemented with PI and PID techniques. Determining the controller gain coecients are one of the most signicant problems in order to show a more stable rotor dynamics that eventually leads to better wind turbine performance in terms of both mechanical and electrical qualities. Hence, PID controller was designed and optimized with genetic algorithm technique for a 2 MW DFIG type wind turbine under Matlab-Simulink environment. Gain parameters were optimized for a given wind speed prole from third zone and optimized gain coecients were achieved within the optimization study. A ontroller with an optimum gain coeffcients shows the superior performance than the regular PID performance

Performance comparison of pitch angle controllers for 2 MW wind turbine

As wind energy is becoming more and more signicant for renewable energy, eectiveness of pitch angle controller plays crucial role to achieve higher performance and optimized turbine designs. Aerodynamic performance of wind turbine rotor and consecutively electrical power production of turbine depend on the efficiency of pitch controller design. This work presents the eects of two dierent pitch angle controllers on a 2 MW DFIG type wind turbine under Matlab Simulink environment. The main objective of the pitch controller is to regulate the rotor and generator speed as the input of the controller was generator speed where the output of the controller is to determine the pitch angle. PI and PID control methodologies were used to design pitch controller of the turbine. Through the controller design iterations, settling time, overshoot value, error values and power output values are decided for comparison parameters. Both controller performances in terms of transient and steady state are evaluated

Desing analysis and development of a nacelle main load frame for a 500 kW wind turbine

Wind energy is gaining increasing momentum over the last two decades. Wind energy business is one of the most attractive in renewable energy sectors. While several wind turbine designs are available in the industry, developing a wind turbine for continuous commercial electricity production is one of the challenging engineering problems in todays world. This work involves design, analysis and development of a nacelle main load frame for a 500kw wind turbine as part of the national wind turbine development project (MILRES) of Turkey. Starting from conceptual design stage complete static and dynamic analyses were conducted including the crane loads on the nacelle bedplate. Conceptual and detail design work were conducted using commercially available 3D solid modeling code SOLIDWORKS. Structural analyses such as stress and strain calculations and modal analyses of the main load frame were performed using the finite element method. A hybrid (cast iron main base and weld formed steel extension) structure has been developed to improve stiffness while controlling overall weight. A bolted joint assembly was designed for cast base and steel extension interface. Analytical joint and bolting calculations were confirmed by finite element simulations of the assembled bedplate structure. An iterative design approach has been used. Design and analysis iterations were carried out to improve functionality, weight, and stress levels. For an optimum stress and weight design solution, topology optimization methods were applied to the structure in order to minimize weight while maintaining design safety limits and stiffness of the structure. Topology optimization stage was conducted by commercially available codes OPTISTRUCT and ANSYS shape optimization module. The optimization work resulted in 30% reduction of weight. The analysis results for optimized geometry indicated sufficiently high design safety margins for all design load combinations. Overall, an optimum Nacelle bedplate design has been developed achieving high safety factors with minimum weight

Topology optimization of a 500kW wind turbine main load frame

As wind turbines get larger and larger, nacelle weight becomes more important as it affects cost, logistics and even turbine natural frequencies. This work presents a nacelle weight optimization process for a main load frame of a 500 kW wind turbine. While the weight is minimized structural strength has been preserved. In order to achieve an effective weight reduction, topology optimization methodology is used with the aid of finite element solvers like OPTISTRUCT. Combined wind, generator and gravity loading condition have been considered while stress analyses are conducted. The work started with an initial over safe 7000 kg design. Through topology optimization iterations 28.57 % weight reduction has been achieved. Using SIMP method, weight reduction or material removal locations were carefully identified. The redesigned nacelle main frame has maximum stress levels less than 40% of the material yield strength

Fatigue analysis approach of a 500kW wind turbine main load frame

As wind industry get larger and larger, maintenance of safety and reliability of the turbine equipment becomes more and more important. Main load frame is one of the most critical components of the turbine and should have a very reliable fatigue safety due to the component is used as a main load transmitter and main mount for all nacelle equipment. This work presents a fatigue life design process for a main load frame of a 500 kW wind turbine. While the cyclic life of the turbine is kept to be an infinite, both static safety factors and weight of the main load frame is preserved optimally. In order to achieve an effective fatigue design, modified Goodman fatigue theory is used with the aid of commercial finite element software. Dynamic strength of the materials and the safety factors of the bedplate is calculated analytically. The stress analyses are conducted with the finite element methodology. The stress oscillations are determined for the both parts of the hybrid bedplate. Values of the maximum and minimum stresses are calculated with the aid of the commercial finite element solver. Through the fatigue analysis iterations quite high fatigue safety factors are obtained with respect to commonly accepted standards' fatigue safeties

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

A novel fuzzy logic pitch angle controller with genetic algorithm optimization for wind turbines

As one of the most preferred renewable energy sources in the contemporary world, wind turbine technology has grown in importance. Blades are among the most crucial parts of a modern horizontal-axis wind turbines. They extract dynamic energy from the wind and convert it to rotational mechanical energy for the turbine. Blades play a significant role in the safety, stability and control of the wind power plant. Blade pitch angles are controlled online via electrical or hydraulic actuators to safeguard the turbine from hazards of extreme wind conditions. The same actuation mechanisms are also active during power production for control purposes. Turbines operate with prespecified generated power references. In order to keep the production at this reference pitch angles are position-controlled with feedback from the power output. Conventionally, linear control methodologies are applied. Recently, soft computing techniques and especially fuzzy logic controllers are applied in this field with promising success. The fuzzy rule base, the employed inputs and parameter values play important roles in the controller performance. This dissertation presents the design of a novel fuzzy logic blade pitch angle controller. Power regulation is carried out by this system which evaluates power error, rate of change of power error and generator speed. This set of inputs, different from the majority of the studies reported in the literature, creates flexibility in the design of fuzzy rules which compute pitch angle references to be applied to the blade actuators. Tuning the many parameters of the three-dimensional rule base, however, proves to be an elaborate task. Evolutionary computing is applied in this thesis for the tuning of these parameters. The controller is tested with dynamic simulations of a 2 MW wind turbine model under fluctuating wind profiles and over nominal wind speeds. The performance of the novel controller is contrasted to a number of traditional pitch angle control techniques. Also tested are these conventional techniques when they are tuned by genetic algorithms. Simulation studies and data from the literature indicate superior performance of the proposed technique. An energy production improvement of 1.1 % is achieved when compared with conventional pitch control technique

Fatigue Analysis Design Approach, Manufacturing and Implementation of a 500 kW Wind Turbine Main Load Frame

The main load frame of a wind turbine is the primary mount for all nacelle equipment and is used as the principal load transmitter. This frame should have a reliable fatigue safety rating because it is a load-bearing component. In this work, the fatigue life design, manufacturing and implementation process for the main load frame of a 500 kW wind turbine are studied. The weight of the main load frame and static safety factors are preserved while the cyclic life of the bedplate is kept infinite. Modified Goodman theory is applied to achieve an effective fatigue design using a commercial finite element software package. Analytical calculations are carried out to obtain the safety factors of the bedplate and dynamic strength of the materials. A finite element approach is employed to perform stress analysis. Stress oscillations are established for both welded and cast parts of the hybrid bedplate, and the maximum and minimum stress values are established. Fatigue safety factors are calculated via fatigue analysis iterations. The obtained safety factors are adequate from the perspective of commonly accepted fatigue safety standards. Welding and casting techniques are applied together for manufacturing of the frame. On-site testing indicates that the wind turbine does not show any signs of fatigue. Rupture, cracks, and abrupt accelerometer reading variations are not observed

Genetically optimized pitch angle controller of a wind turbine with fuzzy logic design approach

An important engineering challenge is the design of a wind turbine’s pitch angle controller. The dependability, safety, and power output maximization of a wind turbine are all impacted by this controller. In this study, a 2 MW doubly fed induction generator wind turbine’s blade angle controller design with a novel fuzzy logic controller is tested in a simulated environment. The evolutionary algorithm technique is used to optimize the fuzzy logic controller with three inputs. A genetic algorithm is used to optimize the specified pitch angle controller for a number of coefficients. After the optimization process, the controller’s performance is assessed in terms of power output, overshoot, and steady-state error characteristics

Performance analysis of a pitch angle controller for 2MW wind turbine under abrupt wind speed conditions

The blade pitch angle regulator is employed in order to reduce wind turbine issues caused by abrupt variations in wind speed. A traditional PID controller is employed in the Matlab-Simulink environment to regulate the power output of a variable speed wind turbine which is 2MW doubly-fed induction generator type. The simulation results indicate that when the wind profile fluctuates rapidly, the output power error and generator speed error are small, and the change in power error is near zero, implying that the conventional PID controller functioned effectively