本論文主要研製一多模組直流/交流變頻器並聯系統,應用於單相備援電力系統。每一變頻器模組由全橋式變頻器及輸出濾波器所組成,並且採用Microchip公司之dsPIC30F2020數位信號處理器作為控制核心,其脈波寬度調變方法為單極性電壓調變技術。 本文採用之並聯架構為主從式架構,其主變頻器之電壓與電流迴路使用比例-共振控制器,以達到穩定輸出電壓及良好的動態響應。從變頻器則使用責任週期補償技術,使得各級變頻器輸出電流一致,進而達到均流控制,並具有熱插拔之功能。 本文設計規格為輸入直流電壓400 V,輸出交流電壓220 V/60 Hz,兩級變頻器並聯總額定功率2000 W,功率開關切換頻率9.6 kHz。由模擬與實驗結果證明,在輸入直流電壓400 V及各負載條件下,整體並聯系統效率高於94%以上,且電壓總諧波失真小於5%。
The object of this thesis is to design and implement a paralleled DC/AC multi-inverter system for single phase back-up power system. Each inverter module consists of a full bridge inverter with output filter and Microchip dsPIC30F2020 as digital signal processor. The pulse-width modulation with unipolar voltage switching is used to control the power stage. The paralleled DC/AC multi-inverter system is a master-slave structure. The voltage and current control loop of master inverter uses proportional-resonant controller to provide stable output voltage and fast dynamic reponse. The slave inverter is with duty compensation to make the same output current among each inverter modules and then achieve current sharing control and hot-swap feature. The design specifications are input DC voltage of 400 V, output AC voltage of 220 V/60 Hz, total power rating of 2000 W, switching frequency of 9.6 kHz. Simulation and experimental results verify the control scheme can cope with input DC voltage 400 V under various load conditions, entire paralleled multi-inverter system efficiency is higher than 94%, and the total voltage harmonic distortion is less than 5%.