California’s main barrier to electrifying transportation is grid capacity: utilities cannot expand transmission and distribution infrastructure quickly and/or cost-effectively enough to meet customer demand. High-power charging for on-the-go electric vehicles (EV) (for example, passenger EVs, fleet vehicles, electric tractors, and electric drayage trucks) increasingly requires grid upgrades to accommodate the power requirements of EV fast charging stations, resulting in long and expensive delays.
To address this issue, the project designed, built, and tested an advanced power electronics module (PEM) that directly integrates charging with distributed energy resources and advanced power management technologies to facilitate direct current (DC) device integration. The project demonstrated how a modular, interoperable technology employed in a novel DC architecture can enable the installation and operation of DC fast charging stations using existing grid capacity without requiring costly upgrades.
In the project, a prototype PEM was integrated with high-voltage onsite solar, energy storage, and the grid (via a small bidirectional alternating current (AC)/DC converter connected to a building panel). The PEM strategically decoupled charging from the AC grid and harnessed the aggregate power deliverability of DC-coupled distributed energy resources. It provides an endto-end power conversion solution sourcing power from a microgrid to deliver the power and voltage requirements of DC-fed EV charging stations. The resulting integrated solution successfully supplied 150 kilowatts at 950 volts to a commercially available DC fast charger without upgrading any utility or site electric infrastructure.
The new DC power conversion equipment, which is connected to a modular and interoperable DC architecture to provide grid-friendly EV charging, enables the timely deployment of DC fast charging at grid-constrained sites.
Author(s)
Richard Mrlik, Zander Mrlik, Intertie Incorporated
