The Future of EV Charging Part 1: Wide-Bandgap Semiconductor

(Joseph Gottlieb, CTO, Tuesday June 22, 2021)

There is ample evidence that electrified vehicles (EVs) are far more efficient than internal combustion engine (ICE) powered vehicles.The average EV is over 77% efficient in converting power from the grid to power at the wheels, compared with ICEs which tend to be between 12% and 30% efficient converting the energy stored in gasoline to power at the wheels. For EVs, about 40% of the lost efficiency (roughly 10% loss in absolute terms) happens in the inverters in the EV charger. For energy conversion devices, a 90% efficiency rate is actually pretty good, but if the EV charger represents 40% of the power loss in an EV, can it be improved? The answer to that for DC fast charging is wide-bandgap semiconductors such as Silicon Carbide (SiC) and Gallium Nitride (GaN), which can reach efficiencies of 98%-99%, which can increase the overall efficiency of EVs to 85%-86%.

In addition to improving charger efficiency, GaN and SiC have two other advantages. Wide-bandgap semiconductors are less affected by high temperatures than conventional semiconductors, and can sustain higher energy densities. This makes these materials significantly more attractive for power electronics than conventional semiconductors. An addition, since wide-bandwidth devices operate at higher switching frequencies than conventional semiconductors, the magnetics required in chargers (transformers and inductors) can be considerably smaller. Since these devices are often contribute the most weight and volume to the design of DC fast chargers. This not only reduces the size of these systems, but also their cost. So with wide-bandgap materials, you have a winning trifecta: significantly higher efficiency, half the space and weight, and lower cost!

If you are looking for made in the USA high-power DC fast charging systems for those EVS, look to Rhombus Energy Solutions. Our market-leading bi-directional EV charging systems (which are designed from the start for the needs of fleet operators) are designed and built in the USA. Rhombus also excels in the design of high-power smart inverters for next-generation renewable energy and energy storage deployments. Our expertise in energy management system (EMS) software is also embedded in our VectorStat EMS controller and software which is embedded in our EV charging systems and smart inverters. We have built over a thousand V2G-capable high-power, high-reliability chargers and bi-directional smart inverters for a variety of different sizes and classes of EVs. Find out how we can help you by contacting us at news@rhombusenergy.com, or by reading our Vehicle to Grid Solution Brief.