The range anxiety and relatively long charging time issues of electric vehicles (EVs) have boosted the development of fast charging technology. With charging light EVs being the main focus in the past decade, a trend of promoting the charging infrastructures dedicated to heavy-duty EVs (HDEVs) such as E-trucks, and Ebuses has emerged to further the electrification of global transportation. Accordingly, the market is calling for advantageous standards, architectures, and power electronic circuits specialized in the fast charging of HDEVs. For the charging of HDEVs, the power rating of chargers can reach an ultra-high-power level (>1 MW) to ensure a charging time comparable to the refueling time of internal combustion engine (ICE) vehicles. At this power rating, the classic full power processing (FPP) two-stage AC-DC plus DC-DC architecture has limited space for improvement in terms of the efficiency and effective cost of the charger circuits. This thesis proposes a solution to the HDEV fast charger topologies. Firstly, the state-of-the-art EV fast charging technology, concepts of the hybrid rectifier, and partial power processing (PPP), which could be beneficial in advancing the charging architecture are reviewed. Based on the results of the literature review, a new unidirectional Input-Parallel-Output-Series (IPOS) three-phase hybrid rectifer topology is proposed and analyzed. This topology is derived from the Input-Parallel-Output-Parallel (IPOP) hybrid rectifier in [1] by connecting the DC-links in series instead of in parallel. The IPOS topology is beneficial at ultrahigh power rating to interface heavy-duty EV batteries which require a high and wide output voltage range, enabling the system to deliver an output voltage range of 800∼1500 V to interface the next-generation of EV batteries with available 600/1200V commercial semiconductors. Besides, the proposed topology is efficient, cost-effective, and scalable with the grid input current harmonic components in compliance with the IEEE-519 standard. The benefits of the IPOS topology are supported by circuit derivation, control strategy, analytical modelling, simulation, and experimental verification of the current modulation technique. Index terms— fast charging, hybrid rectifier, partial power processing, power factor correction, AC–DC converter