We're used to using alternating current–AC–for distribution of power from utility sources, to local substations, then to our homes, offices, and factories, and finally within the structures themselves. Once the AC reaches its final load, whether an appliance, PC, motor, or other electrical/electronic device, we step it down further if needed, and convert to direct current–DC–if necessary.
But a press release on a report from The Darnell Group caught my attention. It discusses the continued growth of DC power distribution in buildings, and what's driving the trend; LED-based lighting, was cited as one major driver.
The AC vs. DC battle has "raged" since Edison promoted DC power while Charles Steinmetz (and General Electric) felt that AC was the way to go. As we know, AC won the battle, since it was so much easier to step up and step down via transformers, and higher voltages greatly reduce resistive (IR) loss; (see my recent column on this, "Is this something for (almost) nothing?".
But high-voltage DC has some advantages over AC, as long as you can do the step-up and step-down efficiently, which we now can do with advanced DC/AC converters and AC/DC rectifiers; there are DC lines in use now running at 100s of kV. In short: new technologies have both changed what we can do (high-voltage DC), and what we want to do (DC distribution to match new loads). The increased availability of DC distribution may be a development to keep in mind. Meanwhile, think about what the architectural impact availability of higher-voltage DC rails will mean for your power-distribution and conversion topologies. The law of unintended consequences can be your friend or your foe!♦