本論文探討微電網之重要元件-電力轉換器(Inverter)系統其熱管理之評估，因較高之電壓或電流將間接地或連續地產生高溫，致使電子元件之使用壽命減短並導致系統效率下降，特別是微電網電力轉換器所使用之絕緣柵雙極晶體管(insulated gate bipolar transistor, IGBT)。本論文5kW電力轉換器之實驗均操作在60Hz之工作頻率與20kHz之脈衝頻率，探討在不同功率下，溫度與速度場之分布、IGBT電路板角度與使用不同散熱材料(散熱膏與散熱墊)之影響。根據實驗結果發現，在較高功率時，IGBT模組之溫度明顯上升且在3kW之放電功率搭配強制對流下(風扇開啟)，可有效地降低IGBT模組之溫度約35°C。在添加散熱膏於IGBT模組與散熱鰭片之實驗結果中，添加散熱膏反而使IGBT模組之溫度上升，其主要原因為熱阻抗(thermal resistance)增加，致使散熱更不易，導致溫度上升。而在更換不同型式之散熱墊中，就可有效地改善其溫度場，其原因為使用厚度(0.2mm與1mm)不一之散熱墊，使其熱阻抗減小，達到改善之目的，在兩種型式之一層與兩層散熱墊中，其溫度差可有效地降低15.4°C與13.1°C，故散熱墊之厚度對於系統之選用是相當重要的一環。而在不同散熱墊之厚度、溫度與熱阻之實驗結果中，溫度越高，熱阻值也隨之增高，其原因為溫度上升，使材料性質劣化，導致熱阻值增加，影響系統散熱效果。;The thermal management of the inverter is of great importance since very high voltage/current will be switched intermittently and/or continuously and high temperature is excruciably detrimental to the service life of electronics such as insulated gate bipolar transistor (IGBT). In this study, a newly developed dual bi-directional IGBT-based inverter with autonomous microgrid system is investigated with particular focus on the thermal management under various operation conditions. The module is operated at the switching and pulse frequencies of 60 Hz and 20 kHz, respectively. The adoption of thermal interface material in either paste or film form had experimentally shown to possess the flexibility tailoring heat transfer performance locally. Experimental studies of heat dissipating film with various hotspot scenarios showed that the temperature difference can be appreciably reduced as many as 15.4°C and 13.1°C, respectively with facilitation of one- and two- layers of heat dissipating film. From the measurement results, the measured peak temperature is highly dominated by the thickness of heat dissipating film, showing the dominance of thickness-dependent thermal resistance and resultant heat accumulation.
