The following is the main works and conclusions of this thesis . the novel upfc needs high power rate because it is generally used in high voltage transmission lines . after studied high - power converters and the literatures of upfc , the main circuit topology of novel upfc base on diode - clamping multilevel inverter is presented and the principle of using novel upfc to eliminate zero sequence and negative sequence currents is analyzed 本文所做的主要工作及得出的主要結論如下:由于upfc一般用于高壓輸電線,其功率等級要求很高,在綜合研究大功率變換器和upfc現(xiàn)有文獻的基礎上,提出了基于二極管箝位多電平變換器的新型upfc的主電路拓撲,分析了用其來濾出高壓輸電線非全相運行時所產生的零序和負序電流的原理。
Based on studying of the multi - level technique , a variable frequency speed regulation system based on the diode clamped three - level inverter is introduced in this thesis in detail . it includes ac - dc - ac main power circuit , snubber circuit , isolated driving circuit by optical fibre , delay time circuit on powering , sampling circuit of current and voltage , protection circuit and etc . a distributed power system ( dps ) which can reinforced the system ’ s security is developed to solve the power supply of the whole system 本文在研究多電平技術的基礎上,研制了一套以二極管箝位式三電平逆變器為基礎的變頻調速系統(tǒng),包括:交-直-交主功率電路,緩沖電路,光纖隔離驅動電路,上電緩沖延時電路,電流、電壓采樣電路,保護電路等。