本文研製一具以數位訊號處理器(Digital Signal Processor, DSP)為控制核心之單相直流/交流轉換器,實現數位式單極性電壓調變之控制方法,以提升電壓應用率及降低諧波失真(Total Harmonic Distortion, THD)。 所提出的電路是以全橋式變頻器為基本架構,並設計適用之輸出濾波器以及回授控制器,實現穩定之單相正弦電壓輸出;整體功率級電路是利用四個絕緣閘雙極性電晶體元件、電感器與電容器所組成。 在整體控制上,採用德州儀器(Texas Instruments, TI)所生産的數位訊號處理器TMS320F28035實現所擬之控制法則,藉以得到數位控制之各種優點。論文中所實現的數位式變頻器之設計規格為輸入直流400 V、輸出電壓110 Vrms/60 Hz、開關切換頻率12 kHz、額定功率500 W以及電壓總諧波失真率小於5 %。經由實測結果,單相變頻器於額定功率下,效率最高達96.9 %,輸出電壓的總諧波失真率均小於5 %,結果顯示控制策略確實可行且符合設計要求。
A digital controlled single-phase DC/AC inverter with unipolar voltage switching is presented in this thesis to enhance the rate of voltage application and reduce voltage total harmonic distortion. In this thesis, a full-bridge inverter is selected for the power circuit structure which connects a low pass filter to obtain the AC voltage required for the load. The used topology of single phase inverter consists of four IGBTs, an inductor and a capacitor. The digital signal processor (DSP) TMS320F28035 by Texas Instruments is utilized to implement the used control method. The design specifications include that DC voltage is 400 V, output voltage is 110 Vrms/60 Hz, switching frequency is 12 kHz and rated power is 500 W. Under nominal load conditions, the efficiency is higher than 96 % and total harmonic distortion of the output voltage is less than 5 %. The experimental results verify the feasibility and functions of the implemented system.