用於改善電網次同步振盪現象之風場電池儲能系統PID控制器設計

Abstract

本論文旨在設計應用於雙饋式感應風力發電機與電池儲能系統併網之PID控制器，且此併網系統經由輸電線連接至電網，用以改善電網端所產生之次同步振盪現象。藉此避免系統因振盪影響，造成風機等相關架構損壞。 設計流程首先建構完整系統之電路模型與非線性數學模型，並將非線性模型線性化後進行小訊號穩定度頻域分析。接續透過參與率分析與靈敏度分析，釐清系統狀態變數、系統特徵值與雙饋式感應風力發電機控制器參數間之關聯性。隨後，利用閉迴路系統之靈敏度分析以及根軌跡分析，選定適當的PID控制器參數，以提升次同步振盪模式之阻尼比。最後，本論文亦比較不同輸入訊號對系統根軌跡特性之影響。 本論文藉由MATLAB®/Simulink軟體進行模擬，並以雙饋式感應風力發電機、電池儲能系統與輸電線所構成之併網架構為模型，驗證所提出之儲能系統控制器在抑制次同步振盪方面之有效性。

The main objective of this thesis is to design a PID controller for the grid-connected system composed of multiple doubly-fed induction generator (DFIG)-based wind turbines and multiple battery energy storage systems (BESS), aimed at mitigating sub-synchronous oscillation (SSO) phenomena in the power grid. The grid connection is established via transmission lines, and the proposed control strategy seeks to prevent structural damage to wind turbines and related components caused by oscillation effects. The design process begins with the development of a complete circuit model and a nonlinear mathematical model of the system. The nonlinear model is then linearized for small-signal stability analysis in the frequency domain. Subsequently, participation factor analysis and sensitivity analysis are conducted to identify the relationships among the system’s state variables, eigenvalues, and the control parameters of the DFIG-based wind turbine. Based on the sensitivity analysis and root locus analysis of the closed-loop system, appropriate PID controller parameters are selected to enhance the damping ratio of the SSO Mode. Additionally, the thesis investigates the effects of different input signals on the root locus characteristics of the system. Simulation studies using MATLAB®/Simulink confirm the effectiveness of the proposed controller in suppressing SSO in the grid-connected DFIG-BESS system.