A 3.3kW Modified LLC Resonant Converter for Grid-Tied EV System Under Wide Voltage Range

Abstract

This study describes the design of a single-phase, two-stage, On-Board charger (OBC) for light loads that may function in the Grid to Vehicle (G2V) operation mode. The first stage AC-DC converter of EV (Electric Vehicle) charger plays a very important role in supporting the grid power factor unity and the H-bridge inverter is regulated for this purpose using a Second Order Generalised Integrator (SOGI) control approach, which exhibits a stable steady state as well as excellent dynamic behaviour. To maintain the international electrotechnical Commission (IEC)-61000-3-2 standard for the power quality PQ of the grid throughout operations. Additionally, the design’s performance has been verified in the presence of Sag and Swell grid voltage and diverse operating conditions. The second stage is the Modified LLC converter is used for DC-DC conversion, this converter is capable of achieving Zero Voltage Switching (ZVS) for all switches. The modified LLC converter uses fewer switches than a conventional LLC converter, which greatly reduces reverse power and turn-off losses while also allowing for significantly higher Voltage conversion. A Proportional Integral controller is implemented to control the DC-DC converter’s switches. Using a PWM controller with a steady battery current, the charging current and voltage of the battery are tracked and controlled. For the 3.3kW system ratings, an extensive simulation analysis is performed. To examine the grid’s reactivity, an inductive load additionally has been attached to the grid.