Large-scale Wind Energy Conversion Research Articles

Permanent Magnet Synchronous Generator design optimization for wind energy conversion system: A review

The wind energy sector has grown significantly over the past several decades as enabling technologies advance. One of the major reasons of such rapid growth is due to the renewability of this eco-friendly energy source that reduces carbon footprints worldwide. The overall costs of large scale wind energy conversion systems can be extremely high, which is deemed to be one of the main dilemmas stakeholders have to face with during the design phase. Generators for large scale wind turbines are generally heavy and huge in sizes, which translate into a hike in upfront and maintenance costs. Design optimizations are crucial in wind turbine generator. Multi-objective optimization is a general approach to the design of the generator because there are always tradeoffs in considerations. In many studies, optimizations are applied on mathematical models and the results are verified by means such as Finite Element Method (FEM). This review paper captures the fact that recent advancements in design optimization of Permanent Magnet Synchronous Generator (PMSG) for wind turbine systems are able to deliver tangible benefits to the renewable energy technology (RET) industry as a whole. Different design approaches, objectives applied in optimization, key variables, and optimization algorithms across different research are also presented in this paper.

Comparative Study of Different Pitch Angle Control Strategies for DFIG Based on Wind Energy Conversion System

Abstract- This paper presents an advanced pitch angle control for large scale Wind Energy Conversion System (WECS) based on a Doubly-Fed Induction Generator (DFIG). Blade Pitch angle control is the extremely popular techniques for regulating the aerodynamic power of the wind turbine and minimize aerodynamic fatigue when the wind speed is higher than its rated value. The traditional control technique is based on the proper system modeling and analytical analysis of the transfer function which are not always available and the non-linearity of the control system. To overcome the problems in the traditional control, the adaptive fuzzy-PID control is proposed in this work. The process of the blade pitch control using adaptive fuzzy-PID control strategy is featured with nonlinearity, multi-variable, time variation and time delay. The simulation results are enclosed which prove the effectiveness of the auto-tuning adaptive fuzzy-PID (AF-PID) controller in improving the dynamic performance of the wind turbine (WT). This article emulated comparative analysis of 1.5 MW Doubly-fed induction generator wind turbine control strategies based on computer modeling in MATLAB/Simulink software.

Multi-objective design optimization of a large-scale directdrive permanent magnet generator for wind energy conversion systems

This paper presents a simultaneous multiobjective optimization of a direct-drive permanent magnet synchronous generator and a three-blade horizontal-axis wind turbine for a large scale wind energy conversion system. Analytical models of the generator and the turbine are used along with the cost model for optimization. Three important characteristics of the system i.e., the total cost of the generator and blades, the annual energy output and the total mass of generator and blades are chosen as objective functions for a multi-objective optimization. Genetic algorithm (GA) is then employed to optimize the value of eight design parameters including seven generator parameters and a turbine parameter resulting in a set of Pareto optimal solutions. Four optimal solutions are then selected by applying some practical restrictions on the Pareto front. One of these optimal designs is chosen for finite element verification. A circuit-fed coupled time stepping finite element method is then performed to evaluate the no-load and the full load performance analysis of the system including the generator, a rectifier and a resistive load. The results obtained by the finite element analysis (FEA) verify the accuracy of the analytical model and the proposed method.

Modeling and Simulation of Grid Connected Permanent Magnet Generator (PMG)-based Small Wind Energy Conversion Systems

A small scale wind energy conversion system has tremendous diversity of use and operating conditions, and consequently is evolving rapidly along with the large scale wind energy conversion system for generation of electricity in either stand-alone or grid connected applications. In recent years, the grid connected small wind turbine industry is primarily dominated by the Permanent Magnet Generator (PMG) machines. The power conditioning systems for grid connection of the PMG-based system requires a rectifier, boost converter and a grid-tie inverter. Such system should be based on an appropriate control strategy to control the aerodynamic power during high wind speed, maximum power production, and maximum power flow to the grid at all operating conditions. This paper presents mathematical modeling and control strategy for the grid connected PMG-based small wind turbine systems. Furling control and expected dynamics are adopted with the wind turbine for aerodynamic power control, while the optimum speed of the PMG is followed to ensure maximum power production. A novel controller is derived from the optimum speed information that promise maximum power flow to the grid by controlling the boost converter output voltage and current through the duty cycle. It is found that the proposed modeling and control strategy is feasible and results are verified through simulation.

Power regulation in pitch-controlled variable-speed WECS above rated wind speed

In medium to large scale wind energy conversion systems (WECS), the control of the pitch angle of the blades is an usual method for power regulation above rated wind speed. However, limitations of the pitch actuator have a marked influence on the regulation performance. In variable-speed mode, the control of the generator torque is able to reduce the effects of the pitch actuator limitations. Nevertheless, in this case the system is multiple-input multiple-output (MIMO) and then the control design results more complex. In this situation advance control techniques, such as optimal control, are an interesting option for a systematic controller design. This work analyzes variable-pitch power regulation above rated wind speed in the context of optimal control. The analysis is approached from a new point of view in order to establish a clear connection between the choice of the optimization criteria and the compromise between power regulation and pitch actuator limitations.