Design and Development of a Two-Level Three-Phase Voltage Source Converter using SiC MOSFET for Grid-Connected EV Charging Systems

Air pollution, global warming and other such environmental issues are causing the governments, manufacturers and consumers to move towards electrification of transportation. Most manufacturers are trying to build better and more efficient electric vehicles (EVs) as it acts as a sustainable alternative to traditional internal combustion engines. In this context, designing better power electronic converters is pivotal. The design of a SiC MOSFET-based charger with two- stages for EV applications is discussed in this paper. The presented charger utilizes a three-phase, two-level voltage source converter as the front end and a buck converter as the back-end stage of the charger. The charger is used for implementing various battery charging modes, like charging under constant voltage and charging under constant current. The converter topology, control strategies, and design techniques employed to optimize performance under various conditions are detailed in this work. Using SiC MOSFET as the switching device gives the overall design an advantage over other Si counterparts because of SiC MOSFET’s low on-state resistance, strong thermal stability, and quick switching speed. MATLAB simulations and experimental implementation are done to confirm the design’s overall operation and effectiveness.