Liangbin Yao

A Rectification Topology for High-Current Isolated DC-DC Converters

This paper presents a novel current tripler rectification (CTR) topology for secondary-side rectification in high-current low-voltage isolated dc-dc converters. Compared with the conventional center-tapped and current doubler rectifiers, the CTR topology has three filter inductors to share the output current, and thus higher current capability and better thermal management can be achieved. Theoretical analysis and experimental results verify that the proposed CTR is a good candidate for rectification topology in high-current dc-dc converters.

Inductor current sharing of current doubler rectifier in isolated DC-DC converters

Current sharing is an important issue in both isolated and non-isolated dc-dc converters. In the paper, average current sharing is modeled and analyzed for isolated dc-dc converters with current doubler rectifier. Important design guidelines and conclusions are provided based on the mathematical modeling and analysis. A modified current doubler rectification is presented to achieve balanced current sharing between two inductors of current doubler rectifier in the half bridge dc-dc converter. Experimental results are presented to verify the analysis and proposed topologies

Digital controller for an isolated half-bridge DC-DC converter

Digital controllers are increasingly being used especially in complex systems, including power electronics systems, because of their advantages. In this paper, design, simulation, and experimental results of a fully digitally controlled half-bridge converter with current-doubler are presented. Digital system blocks effects are considered in the digital compensator design to achieve sufficient closed loop gain and phase margins and verified experimentally. Moreover, additional necessary functions are integrated in this digital controller, such as OVP/OCP functions and dead time optimizing function

Unified analog and digital models for half bridge DC-DC converter with current doubler rectifier

The half bridge DC-DC topology with current doubler rectification is suitable for high current low voltage applications. In this paper, both analog and digital unified state space models and small signal models valid for symmetric, asymmetric and duty cycle shifted controlled half bridge DC-DC converter are derived. The discretized analog model and derived digital model are compared based on the digital controller design. In addition, a digital controller is designed based on the digital model for symmetric half bridge DC-DC converter. The results are verified by experiment.

A Novel Current Tripler Rectification Topology for Isolated DC-DC Converters in High Current Applications

This paper presents a novel current tripler rectification in high-current low-voltage isolated dc-dc converters. Compared with the conventional center-tapped and current doubler rectifiers, the CTR topology has three filter inductors to share the output current, and thus higher current capability and better thermal management can be achieved. Theoretical analysis, comparison and experimental results verify that the proposed CTR is a good candidate for rectification topology in high-current dc-dc converters

Zero-voltage-switching buck-flyback isolated DC-DC converter with synchronous rectification

This paper presents a zero-voltage-switching (ZVS) buck-flyback isolated DC-DC converter with two isolated outputs on the primary side and secondary side respectively, wherein primary-side feedback control is used. The primary output is tightly regulated while achieving rough regulation for the secondary output. Since no control isolation is needed, the cost and complexity are reduced as compared with conventional flyback converters with two outputs. Moreover, no tertiary transformer winding is needed for the primary output with primary-side control, so the transformer copper window utilization and conversion efficiency are improved compared to the multi-output flyback converters. The ZVS operation for two main switches is achieved and is verified by experimental results. Both theoretical analyses and experimental results verify the good regulation on two outputs.

Comparison study of inductors current sharing in non-isolated and isolated DC-DC converters with interleaved structures

Current sharing is an important issue in both isolated and non-isolated DC-DC converters. In the paper, average current sharing is modelled and analyzed for both interleaved multi-phase buck converters and isolated DC-DC converters with current doubler rectifiers. Important design rules and guidelines are provided based on the modelling and analyses. A passive current sharing method is presented to achieve balanced current sharing between two inductors in a current doubler rectifier. Experimental results are presented to verify the modelling of the proposed topology

Hybrid discretization in power converters' digital controller design

Digital compensator design is an important and essential step to achieve stable power converter with good steady-state and dynamic performance. Generally there are two digital controller design approaches: The digital redesign approach and the direct design approach. In this paper, hybrid discretization (s-to-z transformation) approach is applied to power converters digital controllers/compensators to achieve better redesigned controller. This is because of the fact that two or more transformation methods with opposite warping effects can be hybridized when discretizing the analog transfer function to reduce the total warping effect. Hybrid discretization can be implemented by different ways, of which three were discussed in this paper. Theoretical, design and simulation results show that better controller/compensator design results, which are closer to the analog case, can be achieved using hybrid discretization technique in the digital redesign approach rather than using single transformation method

A New Family of Rectification Topologies

A new family of rectification topologies are proposed in this paper for future low-voltage high-current applications. The proposed rectification technique has N filter inductors to share the output load current. Compared with the conventional center-tapped and current doubler rectifiers, it has higher current capability and better thermal management can be achieved. Besides, the inductor magnetic design is simple and transformer utilization is good. Theoretical analysis and experimental results verify that the proposed current N-tupler rectifier is a good candidate for rectification topology in high-cureent dc-dc converters.

Analysis and Design of Half-Bridge DC-DC Converters with Current Tripler Rectification

A half bridge DC-DC converter with a novel current tripler rectifier (HBCTR) is proposed for low-voltage high-current applications. The proposed topology features high efficiency, good thermal management and simple magnetics design. A unified steady-state model is derived for the symmetrical and asymmetrical controlled HBCTR, and the DC analysis shows that the proposed HBCTR topology has high current capability that meets the high-current low-voltage requirements for microprocessor and telecommunication power supplies. Design considerations are presented based on mathematical analysis. Experimental results show the efficiency improvement compared with other conventional topologies