高頻柔性切換UPS用換流器之研製

Abstract

本文針對應用於不斷電系統的輸出換流器，為了提高其功率密度，提出了一種柔性切換的單相脈寬調變換流器電路架構，詳細的說明了此電路的工作原理，並對此柔性切換單相脈寬調變換流器，做了完整分析、模擬與實驗。本文針對雙極性脈寬調變全橋架構之換流器，進行了電路分析與開關損失分析，經由比較不同的柔性切換方法後，選擇箝位模式共振極點柔性切換方法。本論文同時完成了一個可切換於輸出功率為1 kW、輸出電壓為AC 110 V、切換頻率為100 kHz之柔性切換單相脈寬調變換流器，實驗結果顯示所完成的原型電路在額定功率輸出下，整體效率較硬性切換可提高4%。

To increase the power density of the PWM inverter of modern uninterruptible power supplies (UPS), one approach is to increase the switching frequency, however, additional switching losses are usually accompanied with the increasing switching frequency. This thesis applies soft-switching technique in reducing switching losses of PWM inverters used for medium power UPS. The operational principle and switching loss analysis of the H-bridge inverter using bipolar PWM modulation technique have been studied in detail. After evaluation of various soft-switching techniques, a clamped-mode resonant pole inverter (CMRPI) soft-switching technique was adopted in realization of the PWM inverter circuit. Detailed circuit analysis and computer simulation of the developed soft-switching PWM inverter were given. We have constructed a soft-switching PWM inverter with switching frequency of 100 kHz. The rated output power of this prototype PWM inverter is 1kW, its DC bus voltage is 180 V, and its output ac voltage is 110 V. Experimental results show that the constructed soft-switching PWM inverter can reach an efficiency improvement of 4% at rated output.