A Novel Single Coupled-Inductor Boost TPC With Two Inductively Interfaced Ports Suitable for Renewable Energy Integration

Abstract

Three-port converters (TPCs) are extensively used for renewable energy systems (RES) catering to stand-alone load and/or grid. Such systems require an energy storage element (ESE) that necessitates the TPCs to operate in both single-input–double-output as well as double-input–single output modes. Furthermore, the ports connecting RES and ESE should preferably be inductively interfaced facilitating a low ripple current for enhancing the power extraction from RES, and for extending the lifetime of ESE. Single inductor-based TPCs, despite offering high power density, lack inductively interfaced ports. To address the aforesaid issue, this article proposes a single coupled inductor-based TPC in which RES and ESE are inductively interfaced. This solution is named coupled inductor based three-port converter (CIBTPC) and is derived by coupling the inductors of an existing three-switch boost TPC. The CIBTPC offers the following advantages over its uncoupled counterpart: reduced ripple current with the same core size and improvement in overall efficiency. The operation of the CIBTPC is illustrated by implementing a solar photovoltaic-based dc stand-alone and nanogrid scheme with battery backup. Validation and performance analysis of the overall system is carried out utilizing a 400 W experimental prototype.