阻抗源變流器之電力轉換研究

Abstract

風力發電、燃料電池或是太陽能發電等再生電力為具有潛力發展的潔淨式能源，其中電力轉換系統大多為交流-直流-交流併網系統，系統中產生的直流電源經常為不穩定狀態，需要在直流-交流轉換器前級加入直流-直流轉換器，以提昇直流鏈電壓。阻抗源變流器以其獨特的阻抗電路，可避免使用直流-直流轉換器，減少驅動電路的成本與系統的複雜性，其原理為利用阻抗源變流器之短路狀態，即使直流電源不穩定，仍可以使變流器輸出之電壓昇壓或是降壓，為一個升降壓的轉換器，而且不需加入上下臂之盲時，可減少輸出電流總諧波失真(THD)為其優點。本研究完成風力發電轉換器與阻抗源變流器之驅動電路實作及模擬，轉換器的形式為AC-DC-AC轉換器，永磁同步發電機整流以二極體全橋整流，減少風力發電成本，阻抗源變流器將直流電壓轉換成三相交流電壓，三相負載為獨立的電感-電阻負載，分析比較傳統電壓源變流器與阻抗源變流器之優缺點。

Wind energy, Fuel cell, or Solar power system are potential renewable energies. The power conversion systems are often AC-DC-AC system connected to the grid. But DC-link voltage behind the AC-DC rectifier is usually not constant. In order to raise the DC-link voltage level, in traditional we prefer to add a DC-DC converter between the rectifier and inverter. Unique impedance circuit of Z-source inverter could be used as DC-DC converter, which has capability of boosting the DC-link voltage by adding the short through states even the DC-link voltage is not constant. And there is not necessary to add dead time for Z-source inverter, which output current’s total harmonic distortion (THD) is lower. This paper implements the AC-DC-AC converter for Permanent magnet synchronous generator using the diode rectifier and Z-source inverter. The AC load is three phase inductive and resistive load. Traditional voltage source inverter and Z-source inverter are introduced and compared with each other.