Power electronics: a transformer with intelligence can operate on both AC and DC and, thanks to high voltage semiconductors, be programmed to redirect the flow of electricity based on demand or supply.
A. High voltage AC semiconductor rectifier.
B. High voltage semiconductor DC / DC converter.
C. High frequency transformers.
D. Control schemes.
In a laboratory designed to simulate residential neighborhoods, Alex Juan is working to upgrade outdated electrical grids into something more like the Internet - a network that can send energy not only from centralized power plants to consumers, but from any source to any place Any route has meaning. To that end, Huang, professor of electrical engineering at North Carolina State University, is developing transformers that now reduce the voltage distributed across neighborhoods so that it is suitable for use in homes and offices.
Its new transformer will enable the grid to deal with problems it was never designed for, such as charging large numbers of electric vehicles and consuming excess electricity from residential solar panels. Smart meters in homes and offices can help by providing detailed information about the flow of electricity, but precise control over this flow is also necessary. This will not only stabilize the power system, but also improve the balance of supply and demand, reduce congestion during consumption peaks, which ultimately reduces the need for power plants.
“We need a brand new device to sit between homes and the network and act as a buffer to keep the network stable no matter what happens in the homes,” Huang says. Conventional transformers only handle alternating current and require manual adjustments or cumbersome electromechanical switches to reroute energy. He wants a compact transformer that can handle both direct current and alternating current and can be electronically controlled to respond almost instantly to fluctuations in electricity demand and supply. For example, if one neighbor plugged an electric vehicle into an AC charger, he might react by plugging in unloaded DC power from another neighbor's solar panels.
To build such a transformer, Huang began developing transistors and other semiconductor devices that can handle thousands of volts, establishing the Center for Advanced Renewable Energy and Power Management Systems in North Carolina in 2008. His first transformer had silicon-based components, but silicon is too unreliable for large-scale use at high voltages. Thus, Huang pioneered the development of semiconductor transformers based on silicon and carbon or gallium and nitrogen compounds, which are more reliable in high-power applications. He expects to have a test version of the silicon-carbon transformer in two years, and have a device that utilities can test in five years.
Juan's transformers could make connecting a solar panel or electric vehicle to the mains as easy as connecting a digital camera or printer to a computer. This will reduce our dependence on fossil fuels as it increases the ability of small-scale sources of clean electricity to contribute to the grid. As he says: "The real benefits to society will come when the cumulative effect of the many small generators is reaped, which we hope will become renewable and sustainable sources of electricity."
Source David H. Friedman