具單位功因併網饋電能力之單級太陽能微型逆變器

A Single-Stage Grid-Connected Microinverter with Unity-Power-Factor for Photovoltaic Applications

太陽能微型逆變器 （PV Microinverter） 主要用於光伏模組發電並將電力饋入市電，相較於傳統集中式 （Centralized） 或組串型 （String） 逆變器具有較高的太陽能追蹤效率、容易安裝、單價低與使用壽命長等多個優點。本文發表目的在於具體化實現一基於交錯並聯返馳式電路拓樸之單級太陽能微型逆變器，其輸入最大瓦數為250 W，可應用於60/72 Cell 所組成的單片光伏模組、輸出達230 W 並能直接與220 V 交流市電系統併聯饋電。本文首先介紹單級微型逆變器的電路架構與系統操作原理，接著針對一些關鍵元件的設計及選用進行說明；為了符合UL 1741 併網法規要求與防止孤島現象發生，逆變器實作系統亦透過監測市電網路電壓、電流與頻率／相位等參數輔以被動式偵測方式以達到保護功能。最後，提出一些實驗結果以驗證本文所實現之太陽能微型逆變器具備商品化可行性。

Grid-connected photovoltaic (PV) micro-inverters deliver the solarenergy from a single PV panel to AC utility. Compared with conventionalcentralized/string inverters, micro-inverters have several advantages, suchas higher maximum power tracking efficiency, easier installation, lower unit price and a longer life-time. In this paper, a single-stage grid-connectedmicro-inverter based on interleaved flyback converter topology is presented.First, the circuit topology and system operation principle of the studiedmicro-inverter are introduced. The design considerations of the key componentsare also described. To comply with the UL 1741 regulation, therealized system monitors the grid voltage, grid current as well as gridfrequency/phase, and then these parameters are combined with the passivedetection method to prevent the islanding phenomenon. Finally, a prototypewith input power rating of 250 W and output power rating of 230W/220 Vac is constructed and compatible with 60 cell and 72 cell solarmodules applications. Experimental results verify the feasibility of thedeveloped micro-inverter.