| Summary: | 碩士 === 遠東科技大學 === 電機工程研究所 === 103 === The conventional type of half bridge converter working mode as a hard switching control behavior. It with a lot of disadvantage characters such as high switch losses、high voltage/current stress、serious EMI problems、harmonic issue… and so on.
Besides, the conventional battery charger require an extra constant current design between the output and battery charger in case over chargedcurrent damage the battery device. Unfortunately, this charger circuit may alsoreduce the overall efficiency by some of conduction losses.
The research propose of this thesis are trying to solve the conventional topology’s drawback and also trying to improve the converter’s overall efficiency to the certainly level.
In this thesis, proposing a half bridge charger converter with zero voltage and zero current as a soft switching enhance efficiency solution.(refer to drawing 1)
The application principle is that the half bridge switcher was controlled by KA3525 PWM controller and through the LC resonant rank design which couldoperate in the CCM mode condition. The purpose of zero voltage and zero current operation is to reduce the converter’s switch losses number, so that it is easy to reach the high efficiency requirement. Another benefit is that itwon’t need to set an extra charger circuit in this application. In his case, the battery charger control was determinate by LC component design, so the solution are simple、low cost, and with very high perform efficiency.
In rectifier and filter section, this thesis propose the current double solution, since the current double solution just use two diodes for the rectifier, it could save two the others diodes conduction losses during the rectifier process, so it could also help to improve the overall efficiency to the certainly level.
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