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) which necessitates the TPCs to operate in both Single Input Double Output (SIDO) as well as Double Input Single Output (DISO) modes. Further, the ports connecting RES and ESE should preferably be inductively interfaced facilitating low ripple current for enhancing 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 paper 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. CIBTPC offers the following advantages over its uncoupled counterpart: (a) reduced ripple current with the same core size and (b) improvement in overall efficiency. The operation of CIBTPC is illustrated by implementing a solar Photovoltaic (PV) based DC stand-alone and nano-grid scheme with battery backup. Validation and performance analysis of the overall system is carried out utilizing a 400W experimental prototype.