Investigation of Zero-Voltage-Switching characteristics of Phase-Shifted Full Bridge with Current Doubler circuit
Date Issued
2006
Date
2006
Author(s)
Tseng, Jerry
DOI
zh-TW
Abstract
The phase-shift full-bridge converter with current-doubler circuit in the output is often used in medium- power high-current low-output voltage applications. The research reported in this thesis is to investigate the soft-switching characteristics of the main switches. It’s well known that the main switches in the “leading leg” can be zero-voltage turned on without much of a problem, but not necessary so for those in the “lagging leg”. The focus of the thesis is to investigate the conditions affecting the zero-voltage turn on of the main switches of the lagging leg.
In the thesis, equations will be derived to show mathematically how the converter design and the operating condition affect the ZVS switching. Software simulations were run to confirm the conditions derived. A comparison was also made between the current doubler secondary circuit and the center-tapped secondary circuit working in conjunction with the phase-shifted primary was made.
It’s found out that although the magnetizing inductance never gets involved in the resonance to achieve ZVS, the magnetizing current indirectly affect the primary current which plays a dominant role in determining if ZVS can be achieved. It’s also found out that current doubler circuits, compared to the center-tapped circuit, make it easier to achieving ZVS condition even at light-load condition. This is because the current in the output chokes in the current doubler always operates in the continuous mode even at light-load condition, unlike that of the center-tapped counter part. Therefore, the conduction duty cycle stays about the same for the full range of load which causes a larger magnetizing current and makes it easier to achieve ZVS condition at light load. The information obtained in the thesis is valuable for designing such a converter for high efficiency.
Subjects
全橋相移電路
零電壓切換
倍流輸出
Zero-Voltage-Switching
Phase-Shifted
Full Bridge
Current Doubler
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-95-R93921019-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):8d055f136f559b3a0ca744090cf24469