DESIGN AND MODELLING OF BOOST PFC AND SEPIC PFC FED HALF BRIDGE LLC RESONANT CONVERTER FOR ON BOARD CHARGING APPLICATION

Abstract

This project describes a half-bridge LLC resonant converter followed by a power factor corrected (PFC) boost converter in an electric car battery. The suggested charger employs a boost converter as the front-end dc-dc converter, which operates in continuous conduction mode (CCM) of the input inductor to provide harmonic-free AC mains current. As the second stage, a Half-Bridge LLC resonant converter is used to accelerate battery charging. An active power factor controller (APFC) manages the DC-link voltage while also maintaining sinusoidal input current. Pulse frequency modulation (PFM) is used after the PI-controller to adjust the battery's output. On the MATLAB/Simulink platform, the proposed charger's steady-state and dynamic performance are evaluated for a range of supply voltage and load conditions. In the above configuration with first stage as the PFC Boost converter the problem of high inrush current is there. Therefore, in the second part of this project, a PFC-SEPIC fed LLC resonant converter for an on-board private charging unit is proposed which eliminates this problem of high inrush current. The PFC-SEPIC converter at the input stage is intended to function in continuous conduction mode (CCM) and enhances power quality execution on alternating current mains for a vast span of output voltages and also provides capacitive isolation. The design for VS = 85V and TDD less than 3.895% for varied input voltages and battery voltages at different loads, is affirmed using MATLAB/SIMULINK.