Advanced DC–DC Converter Topologies for Electric Vehicles: Wide Bandgap Technologies, Emerging Trends and Future Challenges

ABSTRACT The accelerating shift towards electric vehicles (EVs) has intensified the demand for efficient, reliable and scalable power electronic converters (PECs), which are critical in managing energy flow between batteries, traction motors, regenerative braking systems and auxiliary loads. This paper presents a comprehensive review of DC–DC converter topologies across four major EV architectures: battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug‐in hybrid electric vehicles (PEVs) and fuel cell electric vehicles (FCEVs). Converters are categorised into unidirectional, bidirectional and multi‐input types and evaluated by voltage gain, ripple mitigation, efficiency, switching strategies and control complexity. Typical efficiency ranges are highlighted: nonisolated bidirectional converters at 83%–88%, interleaved topologies commonly 90%–96% and resonant converters using wide‐bandgap (WBG) devices at 95%–98.9%. Advanced designs, such as zero‐voltage switching (ZVS)/zero‐current switching (ZCS), isolated full‐bridge and multiport converters, are explored. Special emphasis is placed on silicon carbide (SiC) and gallium nitride (GaN) devices for high‐frequency operation in the hundreds of kHz (with lab demonstrations approaching ∼1 MHz) and high‐power density. Persistent challenges include electromagnetic interference (EMI), thermal management during ultrafast charging (ΔTj > 70°C) and WBG reliability. Emerging directions include AI‐based diagnostics achieving > 99% capacitor ageing prediction, vehicle‐to‐grid (V2G) with ISO 15118 and the integration of silicon photonics and quantum control for next‐generation EVs.