A Multifunctional Isolated and Non-Isolated Dual Mode Converter for Renewable Energy Conversion Applications

Yiwang Wang,Chun Gan,Yong Yang,Kai Ni,Houjun Tang,Xinhua Li

doi:10.3390/en10121980

Abstract

In this paper, a multifunctional isolated and non-isolated dual-mode low-power converter was designed for renewable energy conversion applications such as photovoltaic power generation to achieve different operating modes under bi-directional electrical conversion. The proposed topology consists of a bidirectional non-isolated DC/DC circuit and an isolated converter with a high-frequency transformer, which merge the advantages of both the conventional isolated converter and non-isolated converter with the combination of the two converter technologies. Compared with traditional converters, the multifunctional converter can not only realize conventional bi-directional functions, but can also be applied for many different operation modes and meet the high output/input ratio demands with the two converter circuits operating together. A novel control algorithm was proposed to achieve the various functions of the proposed converter. An experimental platform based on the proposed circuit was established. Both the simulation and experimental results indicated that the proposed converter could provide isolated and non-isolated modes in different applications, which could meet different practical engineering requirements.

Highlights

With the development of power electronics, solid state converters have been widely used in several renewable energy applications [1,2,3,4,5,6]
In some distributed power generators, a single-phase two-stage transformerless circuit is usually used, and the converter can be used to step up the DC voltage [10] in the similar way to boost and buck-boost converters [11]. These topologies are suitable for grid-connected applications with high efficiency, low cost, and compact structures [12,13]
To simultaneously implement the functions of isolated and non-isolated converters and benefit from the advantages of the two converter circuits, this paper proposes a novel multifunctional isolated and non-isolated dual mode converter by increasing the achieve input and output galvanic isolation

Summary

Introduction

With the development of power electronics, solid state converters have been widely used in several renewable energy applications [1,2,3,4,5,6]. With further renewable energy systems, new requirements for power electronic conversion have been proposed. The grid-connected systems use non-isolated converters in most conditions. In some distributed power generators, a single-phase two-stage transformerless circuit is usually used, and the converter can be used to step up the DC voltage [10] in the similar way to boost and buck-boost converters [11]. These topologies are suitable for grid-connected applications with high efficiency, low cost, and compact structures [12,13]. In stand-alone system applications, isolated converters or inverters are mostly employed in the power conversion circuits [14,15,16,17,18,19]

Objectives

Methods

Results

Conclusion