Low Input Current Ripple Phase-Shift Full-Bridge Converter

• Main Authors: Pitipong Sae-Foeng, 馮恩福
• Other Authors: Ching-Shan Leu
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/77513659879876754803

碩士 === 國立臺灣科技大學 === 電機工程系 === 100 === The phase-shift full-bridge converter (PSFB) is widely used for the front-end dc-dc converter due to its essential advantages in low voltage and current stresses on the switches, high efficiency and fixed frequency operation. Moreover, it has several features, for instance, the incorporation of the leakage inductance of the transformer to achieve zero-voltage switching (ZVS) of the primary switches and the elimination of the need for the primary side snubbers enables it suitable for high input voltage and high power conversion applications. Several papers have been published to provide the solutions for the main criteria, such as the ZVS range, dead time, and duty cycle loss, in the design trade-off of the PSFB. Inheriting from the characteristic of the Buck converter, however, large di/dt noise is generated due to its pulsating input current waveform. To meet the EMI regulation, therefore, a larger EMI filter has to be added and becomes the only solution so far. To alleviate the input current, di/dt, recently, several input current ripple reduction converters have been proposed in the literature. As a result, the EMI performance can be achieved by using smaller EMI filter components. It reduces the size and saves the cost from the conventional EMI filter design. However, these converters suffer from the high switching loss due to the hard-switching operation. Therefore, zero-voltage switching technique should be applied to enhance their performance. To explore a full-bridge converter with ZVS and reduced input current ripple properties becomes the motivation of this research and a phase-shift full-bridge with input ripple reduction converter (PSFBRR) is proposed. In addition to meet the EMI regulation with smaller filter components, the significant efficiency improvements can be achieved. Including the ZVS range, dead time, and duty cycle loss, the issue of the input current ripple of the proposed PSFBRR is accompanied to be discussed in detail. Moreover, the input current ripple can be further reduced by way of the current ripple cancellation mechanism. Thus, a phase-shift full-bridge converter with input ripple cancellation (PSFBRC) is also proposed to obtain a continuous input current waveform instead of the pulsating shape. To demonstrate its feasibility, the operation principle and the hardware implementations of the proposed converters with 300~380V input and 12V/30A output are described in this thesis.