An Analysis-Supported Design of a Single Active Bridge (SAB) Converter

Rupesh Jha,Hemant Dashora,Giuseppe Buja,Mattia Forato,Satya Prakash

doi:10.3390/en15020666

Rupesh Jha, Hemant Dashora + Show 3 more

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https://doi.org/10.3390/en15020666

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Abstract

Currently, due to its various applications, the high-performance isolated dc-dc converter is in demand. In applications where unidirectional power transfer is required, the single active bridge (SAB) is the most suitable one due to its simplicity and ease of control. The general schematic of the SAB converter consists of an active bridge and a passive bridge, which are connected through a high-frequency transformer thus isolated. The paper summarizes the behavior of this converter in its three operation modes, namely the continuous, discontinuous, and boundary modes. Later, the features of this converter, such as its input-to-output and external characteristics are discussed. Input-to-output characteristics include the variation of converter output power, voltage, and current with an input control variable i.e., phase-shift angle, whereas the external characteristic is the variation of the output voltage as a function of output current. In this discussion, the behavior of this converter in its extreme operating conditions is also examined. The features of the characteristics are elucidated with the help of suitable plots obtained in the MATLAB environment. Afterward, the specifications of a SAB converter are given and, based on the results of the analysis, a detailed design of its electrical elements is carried out. To validate the features and the design procedures presented in this paper, a prototype is developed. An element-wise loss estimation is also carried out and the efficiency of the converter has been found to be approximately equal to 93%. Lastly, the test was executed on this prototype, confirming the theoretical findings concerning this converter.

Highlights

In todays’ applications, isolated dc-dc converters are becoming more prevalent
Bridge 2 is of different types; for the dual active bridge (DAB) converters, it is of the active type and the bridge sides are composed of controlled switches; for the single active bridge (SAB) converter, it is a passive type and the bridge sides are composed of diodes; for the semi DAB converters, the bridge sides are a combination of controlled switches and diodes [13]; for the phase shift full bridge (PSFB), for unidirectional application, it is a diode rectifier [14,15] and, for bidirectional application, it is of the active type with a clamping diode in bridge 1 [16]
Since only a two-channel oscilloscope was available in the laboratory, two Figures are captured for each conduction mode and, to make the waveforms easy to correlate, v2 is kept common to both the plots

Summary

Introduction

In todays’ applications, isolated dc-dc converters are becoming more prevalent. Their main advantages include a compact structure, galvanic isolation, and excellent efficiency [1,2,3,4,5,6].A variety of converters exist; of these the dual active bridge (DAB) [7,8,9], single active bridge (SAB) [10,11], semi-DAB [12,13], and phase shift full bridge (PSFB) [14,15,16] are the most commonly used isolated dc-dc converters. In todays’ applications, isolated dc-dc converters are becoming more prevalent. Their main advantages include a compact structure, galvanic isolation, and excellent efficiency [1,2,3,4,5,6]. The PSFB converter contains an inductor at the output of bridge 2.

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