太陽光電換流器快速最大功率追蹤及利用數位鎖相數值誤差偵測孤島運轉

Abstract

本論文旨在研製一單相太陽光電直/交流換流器，能夠將太陽能電池模組所產生的直流電流源轉換成交流電流源，換流器的功率級電路是由電流饋入型推挽式轉換器及單極性全橋式換流器兩級電路串聯而成，控制器電路主要由兩個微處理器PIC18F6723以及PIC16F616組成，並藉由上述硬體及韌體，來達成將太陽能模組的直流能量經過交流電流源換流器併聯到市電。其中最重要的部分，本文將提出一個新型快速最大功率追蹤控制技術，經由電流前饋式轉換器來實現高效率太陽光能換流器，以及提出一個半主動孤島運轉偵測的演算法-數位鎖相數值誤差注入特定諧波訊號，來分析並消除不可偵測區域(NDZs)以達成孤島效應偵測保護。 本文將從轉換系統的初步電路架構規劃、設計，各級電路動作原理說明，使用Psim及Matlab 模擬軟體來針對輸出電流控制迴路增益，作時域及頻域的暫態、穩態響應模擬，以及太陽能模組所能提供的最大輸入功率進行追蹤模擬。接著再製作一單相太陽光電直/交流換流器，並實驗上述設計之功能及特性。本論文提供模擬及實驗結果，來驗證所提出的新型快速最大功率追蹤控制技術、半主動孤島運轉偵測的演算法-數位鎖相數值誤差注入特定諧波訊號的性能，以及可行性分析。

This thesis aims at developing a single-phase Photovoltaic Inverter . The PV Inverter system could converts dc power generated by photovoltaic cells into ac power. The power circuit of the PV inverter is composed of two stages – the Current-Fed Push Pull converter and the Unipolar Full-bridge inverter. The control circuit of the PV inverter is composed of two microprocessor-the PIC18F6723 and PIC16F616.By above hardware and firmware, The output of the current controlled PV Inverter is directly connected into utility grid system. There are two novel operation functions proposed，one is a high efficiency Photovoltaic Inverter implemented by Current-Fed converter with a novel fast MPPT control，the another is Non-Detection Zones(NDZs) of Islanding eliminated by digital Phase-Lock-Loop’s(PLL’s) numerical error. The operating principle of the conversion system at different stages are analyzed by Psim and Matlab through primary circuit construct and design. The simulation and experimental results are presented and discussed in this thesis to demonstrate the performance of the PV Inverter system and verify the feasibility of the proposed novel operation functions.