DESENVOLVIMENTO DE UM CONVERSOR CA/CC TRIFÁSICO NPC PARA O CARREGAMENTO OFF-BOARD DE VEÍCULOS ELÉTRICOS

Abstract

This work presents the study and implementation of a three-level NPC (Neutral Point Clamped) converter with clamping diode, applied to the charging system of electric vehicles (EVs). The NPC converter is widely used in high-power and high-voltage applications, as it offers higher efficiency and lower harmonic distortion levels, compared to conventional two-level converters.In addition, the three-level architecture allows bidirectional power flow, a fundamental feature for modern vehicle charging systems, in which EVs can act both as load and as power source (Vehicle-to-Grid, V2G), contributing to the stabilization of the electrical grid. In this study, the dq0 control technique with MATLAB/Simulink software was used, a method based on synchronous variables, enabling more precise control of voltage and current in the conversion process, ensuring efficient charger operation. To control the grid phase, the PLL (Phase-Locked Loop) was implemented, allowing adequate synchronization between the grid voltage and the converter, ensuring a stable and accurate conversion. The dq0 control, together with the PLL,provides a better dynamic response and system stability under load variation conditions. The simulation results show that the grid alternating current presented a THD of 4.10%, below the 5% limit established by IEEE standards, evidencing the effectiveness of the three-level NPC converter in reducing harmonic distortions. The system minimizes current ripples, improves the quality of energy delivered to the battery and enables bidirectional applications, such as the flow of energy between the grid and the vehicle. The proposed system shows promise in EV recharging applications, contributing to the development of more sustainable and efficient technologies in the electric mobility sector.