| With the progress of science & technology and the increased sense of energy conservation and environment protection, the requirements of power supply's quality & efficiency is becoming higher and higher. The conventional power supplies utilized for high efficiency adopting full-bridge rectifiers generated grid pollution. More than 20 years ago, APFC technique took birth and has been researched since then. Now the research has been transferred from breakthrough one bottleneck to the synthesized performance.CRM mode APFC with frequency limited and lossless passive soft-switching was analyzed in this dissertation. It includes 6 chapters.APFC had been researched was introduced and the comparison was made in more aspects, as isolated/non-isolated, one stage/two stages, control strategies and etc. in Chapter 1. After that, it was indicated that APFC operating in CCM and CRM are more comparative while they have shortages respectively. Based on analysis of how it caused, CRM mode APFC with frequency limited and lossless passive soft-switching was presented.Design and parameters selection of the converter was accomplished after theoretical calculation for conventional CRM mode APFC and analysis of frequency-limited principle based on UC3852N in Chapter 2.An IC's deficiency was discovered through simulation and experiment. After that, the harmonics of the input current at mains at 220Vrms input was analyzed.A lossless passive soft-switching topology utilized for the converter was adopted following the design regulation in Chapter 3 at first. Then its operating procedures were analyzed detailedly. And the experimental result was validated at final.The primary elements' loss of the converter was analyzed in Chapter 4, their loss was obtained respectively. The comparison between calculation and measurement was presented subsequently.The conducted EMI in the converter was analyzed in Chapter 5. Then the insertion loss needed to comply with EN55022 (Class A) was designed based on theoretical model and practical measurement of DM EMI and CM EMI, the mains filter was design later. At last the measurement of EMI through the filter was presented.At last, the task during the dissertation was summed up, and some suggestion to the advanced research on CRM mode APFC was presented.Some theoretical analysis afforded in this dissertation may take as a reference not only to research but also to industrial application. |
