具有五質量傳動系統之雙饋式感應風力發電機模態分析與阻尼器設計應用於微電網

Abstract

本論文之主要目的在於透過極點指定法設計風機傳動系統之轉軸振盪阻尼器，以改善風機傳動系統因負載擾動或風速擾動所帶來的轉軸振盪現象，藉此減緩齒輪箱所需承受之機械應力，延長其使用壽命。

為了設計轉軸振盪阻尼器，首先推導微電網頻率控制非線性數學模型，並將其線性化後進行小訊號分析。透過模態分析瞭解風機傳動系統在不同特徵頻率時的動態行為，驗證時域模擬結果之正確性，同時驗證風機傳動系統模行簡化之過程。接著利用極點指定法選定特定頻率之阻尼器參數並制定設計流程圖，使傳動系統能有更好的頻率響應。最後利用特徵值分析釐清輔助頻率控制器與阻尼器加入前後對於頻率控制模式及轉軸振盪模式特徵值的影響。

本論文將使用MATLAB®/Simulink軟體進行模擬風速擾動與負載擾動下之頻率響應，驗證所提出之轉軸振盪阻尼器的可行性與有效性。

In order to inhibit the mechanical vibration of the five-mass drivetrain, a damper is designed to adjust the generator torque at the end of five-mass drivetrain in a doubly-fed induction generator (DFIG) in this thesis. The high frequency components in the drivetrain will be inhibit by adding the damper that designed by pole assignment method. The mechanical stress of the drivetrain will be effectively reduced so that the life of the gearbox can extend.

A linearized model for the microgrid including five-mass drivetrain and damper is first derived and small signal stability analysis is conducted. The dynamic response of five-mass drivetrain at different eigenfrequencies is analyzed by modal analysis. It can validate the correctness of the time domain simulation results and the process of order simplification of drivetrain. Then, the parameters of the damper are chosen by pole assignment method and formulate a design flow chart so that the drivetrain of wind turbine have a better frequency response. Finally, the eigenvalue analysis is used to clarify the influence of the auxiliary frequency controller and dampers on the eigenvalue of the system before and after the addition of them.

Finally, the effectiveness of the designed mechanical vibration damper is validated with the dynamic frequency responses in time-domain under wind speed turbulent and load disturbance by using MATLAB®/Simulink.