الفهرس 
Components of Wind Energy Conversion SystemOnly 14 pages are availabe for public view
 |  | from | 171 |  |  |
| | | from | 171 | | |
Abstract
With the continuous increasing in the demand of electrical energy and the depletion of conventional energy sources besides the emissions of carbon dioxide, all of that have been attracted dire needs to find another source of energy. Renewable energy sources offer an alternative solution because they are continuous, environmentally clean and available worldwide. Among renewable energy sources, wind energy attracted a lot of researchers due to its competitive cost. Various techniques have been implemented in wind energy conversion systems (WECS) and it is expected that wind power generation capacity will reach 2,000 GW by 2030 and increased to 25-30% of worldwide electricity supply by 2050.
Recently variable speed doubly fed induction generators DFIGs wind energy conversion systems have become widely implemented due to its flexible control, low cost, high efficiency and many others salient features . However, many challenges face wind energy such as supplying power at point of common connection (PCC) with fast response through a wide and range fluctuations of wind speeds that produce undesirable effects on voltage and frequency levels leading to deterioration in power system performance. In addition, in response to grid faults, a sharp voltage dip at the generator terminals is detected and may sustain longer than the fault duration. The DFIG stator currents will dramatically increase and exceed their rated values. Consequently, larger rotor currents will be observed pushing the dc link voltage to higher values and might lead to converter damage. Consequently, performance enhancement of WECS during fault conditions as well as changes in wind speed is of prime importance for WECS and represents a major challenge in the operation of this system, which is the subject of this thesis.
Various techniques have been developed and implemented to enhance the performance of wind energy conversion systems under normal and transient condition. These include the use of proportional plus integral (PI) control, conventional flywheel, super capacitor and superconducting magnetic energy storage (SMES). In addition, other techniques have been developed to control the pitch angle to achieve desirable performance, during low and high fluctuations of wind using, PI and fuzzy logic control.