Grid-Forming Power Electronics for Low-Inertia Power Systems

Wednesday, April 19, 2017
12:00 PM to 1:00 PM
NHB 1.720
Free and open to the public

Renewable resources and storage technologies are interfaced to the power grid through power-electronics inverters. These energy conversion interfaces are fundamentally different from synchronous generators in that they have limited to no rotational mechanical inertia. Furthermore, there is a wide disparity in ratings between conventional synchronous generators and power-electronics interfaces. For instance, fossil-fuel driven power plants are typically rated for 100's of MVA while inverters are generally no larger than 100's of KVA and can be as low as a few hundred VA in power rating. Taken together, one can hypothesize that the future power network will have: i) low(er) mechanical inertia, and ii) many (more) actuation nodes. Ensuring stable and reliable operation of such a system will be contingent on scalable models that capture the networked interactions of many inverters and few conventional generators.

In this talk, we will outline techniques for obtaining reduced-order models that capture the dynamics of large numbers of inverters and describe how such models will be critical to analyze the next-generation power grid. After uncovering limitations of conventional power electronics control strategies in realizing low-inertia networks, we will propose a grid-forming controller that ensures system-wide synchronization and stability even in the absence of electric machinery. The performance of the proposed grid-forming controllers will be validated experimentally.

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Brian Johnson

Brian Johnson

National Renewable Energy Laboratory

Brian Johnson received the B.S. degree in physics from Texas State University in 2008. Subsequently, he received the M.S. and Ph.D. degrees in electrical and computer engineering from the University of Illinois at Urbana-Champaign in 2010 and 2013, respectively. He is currently an Electrical Engineer with the National Renewable Energy Laboratory in Golden, CO. He was awarded a Graduate College Fellowship by the University of Illinois in 2008, a Support for Under-Represented Groups in Engineering Fellowship in 2008, and a National Science Foundation Graduate Research Fellowship in 2010. His research interests are in power electronics, renewable energy systems, and control systems.