Development of New Wind Turbine Scheme and Pure DC Wind Farm based on Excitation Controlled Synchronous Generator

Shamsnia, Ali | 2019

632 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52589 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Parniani, Mostafa
  7. Abstract:
  8. In this thesis, a new wind turbine scheme based on Electrically-Excited Synchronous Generator (EESG) and diode-bridge rectifier is proposed and developed. This new scheme is mainly based on the idea of generator excitation current employment as a means of wind turbine control. That is why the new scheme is called Excitation Controlled Synchronous Generator (ECSG) wind turbine. The most important aspects of the proposed ECSG wind turbine scheme are cost-effectiveness, simplicity and higher reliability, as well as higher efficiency. Considerable cost reduction for the converter unit of ECSG wind turbine is so important since costly converter has been one of the main challenges of the synchronous generator based wind turbine schemes for the years. After introducing the overall concept, performance of the proposed scheme in terms of various measures like reliability, cost, losses, etc. is analyzed and its details are developed to overcome the weak points like torque ripple. Performance of the proposed ECSG WT is then compared with two mainstream wind turbine schemes based on synchronous generator, i.e. EESG VSC-based wind turbine and EESG-diode bridge rectifier based wind turbine equipped with boost converter on its DC link. This comparison includes different technical and economic aspects of the three schemes, assuming DC grid connection for the wind turbines. In addition, another comparison is made between the recently introduced Siemens 2nd generation DC Grid Access Offshore wind farm and a wind farm with similar structure, but using Excitation Controlled Synchronous Generator-based wind turbines. The results of these comparisons declare that the new wind turbine scheme has promising characteristics, especially regarding economy, reliability and efficiency.Thereafter, ECSG based wind turbine is employed for AC grid and next generation DC grid wind farms. This scheme fits best for the DC grid wind farms. It is also demonstrated that this configuration greatly simplifies the wind farm converter system and effectively reduces its cost. Series connection of diode-bridge rectifier outputs in 12-pulse or 24-pulse structures of ECSG along with appropriate selection of generator voltage rating, allows direct grid connection of this wind turbine generator to DC grid wind farm, resulting in a much simpler electrical layout for such wind farms. An appropriate configuration is also developed for the ECSG WT based DC grid wind farm, and a three-level control system is proposed for its optimum operation, while meeting the technical requirements. Simulation and experimental results confirm the effectiveness of the proposed wind farm
  9. Keywords:
  10. Offshore Wind Farms ; Torque Ripple ; Wind Turbine Cost ; Wind Turbine Efficiency ; Excitation Controlled Synchronous Generator-based Wind Turbine ; Diode Bridge Rectifier-based Wind Turbine

 Digital Object List