Simulation of fuzzy logic and PI control methods on a bridgeless isolated SEPIC converter for electric vehicle chargers

Abstract

Studies in literature and the increasing trend of electrification show that electric vehicles (EVs) will become more widespread in the future. However, the growing demand for EV chargers causes an overload on the grid. Furthermore, EV chargers generate power factor distortion and harmonics, which contaminate the grid and lower the quality of power. Therefore, power factor correction (PFC) is applied by EV chargers to mitigate the harmonics. As defined in the IEC 61000-3-2 standard, the total harmonic distortion (THD) shall be less than 5%. In this study, a better PFC operation is achieved with the proposed bridgeless isolated single ended primary inductor converter (BL SEPIC) topology as an EV charger instead of conventional converter topologies that have diode bridge rectifiers (DBR). Also, the study has better THD outputs as compared with the similar bridgeless (BL) topologies in literature thanks to the simulated control methods of the proportion-integration (PI) and fuzzy control. Moreover, these control methods are compared with each other in terms of THD suppression performance, stability, robustness, and computational effort. The results showed that the fuzzy controller has advantages of stability and robustness against the transient conditions, input voltages and load changes for THD suppression while the PI controller has better THD results only for steady state operation with nominal input voltage and full load conditions. The implemented PI and fuzzy controllers are simulated in a MATLAB Simulink environment.