A LLC Step-up PV Micro-converter With An Integrated High-Frequency AC Inter-Connected Energy Storage Unidirectional Power Interface

This paper presents an LLC photovoltaic (PV) step-up converter with an integrated high-frequency (HF) AC-link power interface for distributed energy storage (such as a battery) structure. The proposed converter consists of a unidirectional battery charging and discharging circuits that are either coupled or HF inter-connected with the main PV step-up LLC converter. This configuration directly feeds surplus PV energy to the battery via a single-stage DC/DC conversion process. The descriptions of the proposed power interface and the circuit analysis are provided in this paper. Results on a 600W, 500kHz converter for a 400V DC grid and 96V battery module as well as preliminary hardware results on a 100W, 500kHz 400V DC grid and 48V battery prototype, are provided to highlight the features of the proposed work.