G Naga Brahmendra

Bio: G Naga Brahmendra is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Topology (electrical circuits) & Converters. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

A new active soft-switching circuit for full bridge converters

Abstract: This paper proposes an active soft-switching circuit for bridge converters aiming at improving the power conversion efficiency. The proposed circuit achieves loss-less switching for both main and auxiliary switches without increasing the main device current/voltage rating. It is capable of operating at elevated switching frequencies of several hundreds of kHz, at low and high power levels with a wide range of load variations. A winding coupled to the primary of power transformer ensures soft switching for the auxiliary switches during turn-on and turn-off. Phase Shifted Full Bridge (PSFB) topology is chosen to validate the design. Operation principle with analytical expressions for the proposed circuit are outlined. The proposed active soft switched PSFB DC-DC converter circuit is designed and implemented for 350 W, switching at 100 kHz. The simulation and experimental results are presented. Experimental results are used to validate the analysis.

An Active Soft Switched Phase-Shifted Full-Bridge DC–DC Converter: Analysis, Modeling, Design, and Implementation

Abstract: A novel active soft switched phase-shifted full-bridge (PSFB) dc-dc converter is presented in this paper. An auxiliary circuit is added to the pulse width modulation counterpart to achieve the soft switching. The proposed circuit achieves soft switching for both main and auxiliary switches, without increasing the main device current/voltage rating. The auxiliary circuit is gated appropriately in order to achieve zero voltage switching for lagging leg. Tapping in the primary winding of power transformer is added for the purpose of commutation. The proposed circuit is capable of operating at elevated switching frequencies of several hundreds of kilohertz in a range of line and load variations. Steady-state analysis and evaluation of losses for the proposed circuit is presented. Analytical models valid for steady state and dynamic performance are proposed. A 350-W, 100-kHz active soft switched PSFB dc-dc converter prototype is implemented. The proposed analytical models are validated experimentally on 350-W prototype. Experimental results verifying steady state and dynamic models are presented.

A High Efficient DAB Converter under Heavy Load Conditions Using Inner Phase Shift Control

Abstract: In heavy load conditions, the dual active bridge (DAB) bidirectional dc-dc converter transfers the power with lower efficiency due to the existence of larger circulating power flow (CPF). This paper proposes an inner phase shift (IPS) control of DAB converter to improve the efficiency under heavy load conditions by minimizing the CPF. In addition, it reduces the current stress and achieves a wide range of soft switching region. The detailed operational waveform, average power transmission analysis of DAB in the proposed IPS control has been discussed in this paper. And also, this paper presents the zero voltage switching (ZVS) characteristics and its requirements are investigated in detail. Furthermore, the operation principle of theoretical study has been validated through simulation and confirmed with the experimental demonstration.

Soft-Switching Secondary-Side Modulated Multi-output DC/DC Converter with Extended ZVS Range

Abstract: The aim of this study is to develop a closed loop single-input multiple-output (SIMO) dc–dc converter. Multiple output converters (MOCs) are widely used for applications which require various levels of the output voltages due to their benefits in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, Space Vector Pulse Width Modulation method to regulate all the outputs in high precision is proposed and applied for the multiple output battery charger based on the phase shift full bridge topology to charge a multiple number of batteries at one time. The proposed system is characterized by good dynamic properties and high efficiency because the converter transistors are switched in ZVS conditions. A theoretical analysis to provide relations for system design, and the laboratory model investigations to validate the system characteristic is given in the paper.