Songquan Deng

A new control scheme for high-frequency link inverter design

A high-frequency link inverter design with bi-directional power flow using cycloconverter techniques is proposed in this paper. A new control scheme is used to reduce the switching losses and overall size. Detailed operation modes are discussed and the harmonic components for the key waveforms are analyzed with theoretical calculation. The control scheme is verified by both the simulation and experimental results.

Unified steady-state model and DC analysis of half-bridge DC-DC converters with current doubler rectifier

Half-bridge DC-DC converter with a current doubler rectifier is suited for low-voltage high-current on-board DC-DC converters. In this paper, a unified steady-state model for both asymmetric and symmetric half-bridge DC-DC converter is derived, and the converter DC solution is obtained. Based on the steady-state solution, several issues, such as inductor current sharing and transformer DC bias of magnetizing current, are addressed. In addition, a series of design rules resulting from mathematical analysis are discussed. The analysis is verified by simulation and experimental results.

Unified steady-state and dynamic modeling for symmetric and asymmetric half-bridge DC-DC converters with current doubler rectifiers

Half-bridge dc-dc converter with a current doubler rectifier is particularly suitable for low-voltage high-current on-board dc-dc converters compared to other converter topologies. The paper presents the unified steady-state and small-signal models for both symmetric and asymmetric half-bridge dc-dc converters with current doubler rectifiers. DC bias analysis is provided based on the steady-state model. Output-to-control and output impedance transfer functions are obtained based on a unified small-signal model. Design guidelines and issues are addressed. The models and analysis are verified by experimental results

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

An active-clamp snubber for isolated half-bridge DC-DC converters

In the conventional isolated half-bridge DC-DC converter, the leakage-inductance-related losses degrade the converter efficiency and limit the increase of the converter switching frequency. A novel active-clamp circuit is proposed to recycle the energy stored in the leakage inductance and thus improves the converter efficiency. By transferring the energy in the leakage inductance to a capacitor, the leakage inductance energy is recycled. Moreover, the proposed active-clamp circuit avoids the body diodes conduction of primary-side switches. Hence the body diodes conduction and reverse-recovery losses are eliminated. The principles of operation and simulation results are presented. The experimental results show the proposed active-clamp circuit improves the efficiency of the half-bridge DC-DC converter.

Power losses estimation platform for power converters

A power losses analysis platform integrating powerful analysis software Pspice/sup /spl trade//, MathCAD/sup /spl trade// and Maxwell/sup /spl trade// capable of calculating losses on the key components in converters is presented. The operational block diagram and the analysis principle, as well as the technical issue, are discussed. One analysis example is given and the prototype is built. The validity of the analysis is verified by the experimental results.

Interleaved current doublers with parallel connected transformers' primary and secondary sides

Interleaving method for isolated topologies is presented in this paper, in which the secondary-side switches operate at lower switching frequency than the primary side switches to improve efficiency and transient response. Moreover, in the presented interleaving method, both primary and secondary sides of the isolation transformers are connected in parallel, allowing sharing of currents at both primary and secondary sides. Theoretical analysis, simulation and experimental results are presented to verify the proposed topology and control method. It is expected that this topology will be a good competitor for low-voltage high-current Point-Of-Load (POL) DC-DC converter applications in present and future generation of ICs for communication systems and microprocessors.

A new peak current control scheme for duty-cycle-shift (DCS) controlled half-bridge DC-DC converters

A new peak current control scheme with capacitor voltage balance compensation for duty-cycle-shifted (DCS) half-bridge is proposed. The voltage balance is achieved by the control circuitry without modifications on the power stage. The implementation control circuitry is simple and easy to be integrated. The scheme is verified by experiment prototype

A modified ZVS half-bridge DC-DC converter

A modified DCS half-bridge DC-DC converter is proposed to achieve soft switching of all switches and to reduce the leakage-inductance-related power losses. The theoretical analysis and experimental results show that the proposed topology achieves high efficiency at high switching frequencies.