Multilevel bidirectional PFC buck rectifier using fuzzy controller for next-gen EV chargers

Driven by the rapid growth of electric mobility alongside energy supply uncertainties and global fuel disruptions, the demand for highly efficient, intelligent EV charging networks has escalated. Front-end power factor correction (PFC) rectifiers are essential for transforming three-phase utility power into stable DC buses while safeguarding grid power quality. However, standard boost-type PFC frameworks necessitate secondary step-down DC–DC stages to safely interface with low-voltage battery packs, which introduces multi-stage thermal losses, elevated switch voltage stress, and bulkier component footprints. To resolve these limitations, this paper introduces an innovative three-phase five-level bidirectional step-down PFC rectifier utilising switched-capacitor (SC) cells for wide-range EV charging systems. The structural state redundancy of the switching matrix naturally ensures sensorless capacitor voltage self-balancing without requiring auxiliary hardware sensors or nested equalisation loops. To optimise dynamic trajectory regulation, the traditional linear PI scheme is replaced by an intelligent Mamdani-type Fuzzy Logic Controller (FLC) operating on a 7 × 7 rule matrix. The proposed single-stage topology reduces active device voltage stresses, lowers grid-side total harmonic distortion (THD), and achieves near-unity power factor tracking. A detailed theoretical study, the circuit working principles, and the control mechanisms are thoroughly described. Moreover, the proposed converter is validated via comprehensive simulations and verified experimentally using a 1-kW hardware prototype model. The observed findings demonstrate a faster dynamic response, highly stable operation, and enhanced power quality metrics. Consequently, the suggested fuzzy-controlled multilevel buck PFC rectifier presents a highly viable alternative for next-generation EV charging systems.