Module-level grid-side power-quality comparison of SiC-based three-phase AC-DC converter topologies for modular high-power EV charging

This paper compares three SiC–based three-phase AC–DC power converter topologies for modular high-power electric vehicle (EV) charging applications: (i) Bidirectional two-level full-bridge; (ii) Unidirectional three-level Vienna rectifier; and (iii) Bidirectional three-level t-type converter. The study targets module-level operation in high-power modular EV chargers and mainly focuses on analyzing the grid-side power quality, quantified by total harmonic distortion (THD) and ripple of the current. This comparison makes use of a deadbeat predictive current controller, implemented as a continuous-control-set model predictive control (CCS-MPC) scheme, common to the three topologies. Simulations are carried out with up to six 100 kW AC-DC modules in parallel, both without phase shift and with a carrier phase shift of 360°/ n between AC-DC modules. The results show that the inclusion of phase shift significantly reduces the grid-side current THD in the full-bridge and t-type power converters, which makes it practically independent of the number of AC-DC modules, whereas the Vienna rectifier maintains significantly higher THD values due to the uncontrollable region associated with the diodes. Finally, experimental results are obtained using a 25 kW reduced scale prototype common to the three studied topologies, considering the operation of a single AC-DC converter module and evaluating grid-side power quality under identical operating conditions.