Boosting PV Self-Consumption with High-Efficient DC-coupled DC Wallboxes for Battery Electric Vehicles

High self-consumption rate of energy harvested from on-site photovoltaic (PV) installations reduces the burden on the grid and is financially favorable from the perspective of tariffs, fees, and taxation. This paper discusses the use of high-power direct-current (DC) charging of Battery Electric Vehicles (BEV) to leverage their high storage capacity to increase efficiency and self-consumption, especially during times when PV yields are high and feed-in tariffs are lowest. Switching from alternating current (AC) BEV charging to DC charging enables 100% self-consumption rates even from larger PV installations, such as the 30 kW arrays incentivized by the German government, independent of the EV’s AC charging limit (in most cases 7.4 kW to 22 kW), while also increasing efficiency by eliminating DC/AC AC/DC conversion steps along the way.