A New Family of ZCT-PWM Isolated DC-DC Converters with the Optimized Control Strategy ZCT Cell On Secondary Side
ABSTRACT To overcome the complicated strategy and circuit implementation issue for control of the conventional ZCS converter to derive the driving signal for the auxiliary switch, a novel ZCT cell which greatly simplifiers the control strategy by directly extending the duty duration to be the whole off-time of the primary switch is proposed in this paper, where the control circuit is implemented only by a logic inverter and two sets of RC combinations with the same parameters. When preferably placed on the secondary side, the proposed ZCT cell can not only help the converter to achieve ZCS for the primary switches and the ZCT for auxiliary switch wherein itself but also soften the communication of the secondary rectifiers. In addition, the behavior of ZCS has no interaction with primary side ZVS process, therefore a fully soft-switching (ZVS on and ZCS off) converter can be easily obtained. The detail operation principles and design considerations, as well as the family of the new ZCS converters, were presented. A prototype with the fully soft-switching dual switch active-clamped forward topology suitable for being the front-end dc-dc converter in the server system, whose highest conversion efficiency is 95.5%, was built to verify the validity and applicability of this proposed ZCT cell.
Conference Proceeding: High power high frequency zero current transition full bridge DC/DC converter[show abstract] [hide abstract]
ABSTRACT: A novel zero current transition (ZCT) full bridge PWM DC/DC power converter is proposed. Based on the ZCT technique, this circuit realizes the ZCS of the active switches and the auxiliary switches. In the full range of loads, it can be operated in the constant frequency soft-switching mode. On the basis of the illustration of its operation principle, a detailed design approach is included in this paper. Simulation results and the experimental results of a 5 kW 50 kHz DC/DC power converter are also presentedApplied Power Electronics Conference and Exposition, 1998. APEC '98. Conference Proceedings 1998., Thirteenth Annual; 03/1998
Conference Proceeding: PWM DC-DC converter with a resonant commutation means[show abstract] [hide abstract]
ABSTRACT: The proposed converter is a hybrid converter consisting of a pulsewidth modulation (PWM) DC-DC power converter and a set of current mode resonant circuits including a control switch. The power conversion is achieved by a PWM control scheme, and zero current switching is realized by the assistance of a current mode resonant technique. This converter has the easy control characteristics of PWM and the low switching loss of resonant-type converters. The experimental results of a prototype converter with 200 V, 5 kW output show benefits such as a high efficiency of 95%, stable operation, and low noise characteristicsTelecommunications Energy Conference, 1991. INTELEC '91., 13th International; 12/1991
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ABSTRACT: Resonant reset soft switching dual switch forward dc-dc topology is suitable for topology standardization in power electronics system integration since which can be used in high voltage, wide range input applications. To further meet the miniaturization requirement for system integration, the soft switching principle of resonant reset soft switching dual switch forward dc-dc topology was discussed, and an optimized circuit resetting the saturable reactor was presented. With this reset circuit, the saturable reactor core can achieve low profile. Then the operation principles and characteristics of the reset circuit were analyzed in detail and the advantage in dimensions was verified by a 250~400V input, 54V/0~5A output prototype. The experimental results show the converter with the proposed reset circuit has smaller volume by minimum extra power loss when the parameters are appropriately detemined, and the cost also decreases. Therefore the proposed scheme is more attractive for system integration applications.Applied Power Electronics Conference, APEC 2007 - Twenty Second Annual IEEE; 04/2007