具虛功輸出之單相太陽能市電併聯系統

Abstract

本論文研製一組兩級電路架構的具虛功輸出功能之單相太陽能市電併聯發電系統。前級電路為一組具最大功率追蹤功能之電源轉換器，利用升壓型電源轉換器配合改良式擾動觀察法擷取太陽能模組的最大輸出功率。後級電路為一組具虛功輸出功能之單相太陽能市電併聯換流器，利用全橋式單相市電併聯換流器配合非同步和差調變電流控制與漸進式相位移控制，以達到實虛功的控制，並將能量送入市電端。同時研製一組EIA-485通訊介面，讓使用者透過電腦端來監控本PV系統及下達虛功命令以控制輸出虛功大小。本系統使用微控制器做為核心，能有效簡化控制電路，並具有過電流保護、過電壓保護等保護機制，以及待機模式、軟啟動等功能。最後，以實測波形來驗證本論文所提出的具虛功輸出功能之單相太陽能市電併聯發電系統的特性與功能。

A two-stage single-phase grid-tied PV power generation system, which is capable of reactive power output, is presented in this thesis. The proposed PV system consists of a first-stage converter, a second-stage inverter and a communication interface. The first-stage converter is realized by a DC/DC boost converter with the improved perturbation and observation method to draw the maximum power from the PV module. For the second power stage, a single-phase grid-tied full bridge inverter with the asynchronous sigma-delta modulation current control and the smooth phase-shift control is adopted to inject real power and reactive power into the utility line. Also, users can monitor the PV system and set the reactive power command of the inverter via the EIA-485 communication interface. Three microcontrollers are adopted in the proposed PV system to realize the maximum power point tracking algorithm, the reactive power output function, and the EIA-485 communication protocol. Finally, a 1kW prototype circuit is built, and experimental measurements are obtained to verify the performance of the proposed PV generation system.