An Interleaved High Step-Up DC-DC Converter based on Combination of Coupled Inductor and Built-In Transformer for Photovoltaic-Grid Electric Vehicle DC Fast Charging Systems

This paper introduces a high step-up DC-DC converter for the integration of the photovoltaic (PV) energy into the electric vehicle (EV) DC fast charging systems. The proposed converter has an interleaved structure using the integration of coupled inductor (CI), built-in transformer (BIT), and switched-capacitor concepts to achieve high-voltage gain, low current and voltage stresses on the power switches and diodes, and high efficiency. The reverse-recovery problem of all diodes is solved due to the presence of the leakage inductances of CI and BIT. Operation modes and steady-state analysis of the proposed converter in the continuous conduction mode (CCM) are presented. To verify the merits of the proposed converter, a comparison between the proposed converter and other related converters is performed. Furthermore, an 800 W converter with the input voltage of 40 V and the output voltage of 800 V is simulated in PLECS Blockset to validate the theoretical analyses.