A Bidirectional Onboard Charger With Multistep Constant Current Charging Capability

Abstract

This article realizes a bidirectional onboard charger (OBC) for light electric vehicles (LEVs), with multistep-constant-current (MSCC) charging capability. In this MSCC charging operation, the battery current is reduced during the peak-load hours and resumes the rated charging operation amid the off-peak load hours. Since this MSCC operation is a wide load range operation, the controllers of the front-end converter (FEC) and back-end converter are modified. In this context, a Hermite polynomial-derived functional link neural network (H-FLNN)-based deadbeat predictive current controller (DPCC) is introduced to improve the performance of the FEC of the OBC. Moreover, the HFLNN-based DPCC for the FEC regulates the grid current quality during MSCC and distinct operating conditions such as grid voltage sag and swell, distorted grid voltage, and the presence of dc offset error in the measured grid voltage. A laboratory prototype of a 1.1-kW rating is developed to verify the efficacy of the H-FLNN DPCC to keep the grid current power quality (PQ) within the International Electrotechnical Commission (IEC)-61000-3-2 standard throughout the operation. Moreover, the effectiveness of the design is verified amid the grid voltage sag and swell and distinct operating conditions. The experimental analysis depicts that the rated efficiency of the developed laboratory prototype is 90.18% and the analytical power density is 64.16 W/in3. Furthermore, the vehicle to grid (V2G) operation validates the satisfactory design of OBC for bidirectional operation. At last, the comparison of the presented system with existing systems is given to summarize the advantages of the presented system over the existing systems.