OBC advancements
The use of advanced semiconductor technology, SiC MOSFETs, and GaN wide band gap (WBG) FETs and ICs has increased the capacity of OBCs from 3-5kW to 6-11kW, whilst retaining their current size and weight. Several automakers have adopted these more efficient OBCs in their designs.
There is likely to be an increase in the number of vehicles based on platforms employing 800V DC architecture, as opposed to the 400V used currently, to increase power density and reduce charging times further. The high voltage within these platforms reduces internal current flow, resulting in lighter motor windings, wiring and interconnections, increasing the vehicle’s range capability - the reduced current flow and heating effects during charging decrease charge times considerably. The demand for SiC MOSFETs has increased, as they provide the high voltage tolerance and isolation that such voltages need. GaN FET components, covering different voltage ranges, complement SiC MOSFETs in automotive designs. GaN devices are suitable for lower voltage ranges but have a lower switching loss when compared to SiC devices. Research into gallium oxide (Ga203) and other ultra-wide band gap semiconductor materials is ongoing.
Wireless charging technology, which would significantly enhance the experience of owning an EV, is in development and currently out of reach of the consumer. However, it will likely come into operation for luxury vehicles, taxis and “for hire” autonomous vehicles as early as 2024. Once the technology finds its feet and is produced in sufficient numbers, it could find its way into our homes.
Conclusions
As the number of EVs on our roads increases, improved charging times and expanded charging infrastructure are critical elements of the future EV landscape. Available charging points must exceed the current provision to allay range anxiety fears and encourage the broader adoption of EVs. The pace at which new technologies are being developed and employed is unprecedented. Carmakers face many challenges in incorporating these new technologies into their designs. Conversely, there are new opportunities for external partnerships and start-ups. The advent of high-voltage platforms (800V) will reduce charging times considerably. However, facilitating these higher voltages will require further modifications to the charging infrastructure. Wide-scale deployment of SiC MOSFETs and GaN FET semiconductors will permeate the off-board chargers featured in the electric vehicle supply equipment (EVSE) charging points and the OBCs on the EV. A unified charging infrastructure standardised within a country and harmonised across its borders will significantly enhance the e-mobility landscape.
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Conclusion (LC)