Dr. Daniel Opila

General Electric

Note: This is not an official GE site, it is my own work. The company's site is www.ge.com

I spent 4 years at General Electric Power Conversion in Pittsburgh in the Research and Development group, which also handles US Navy work. It was a great opportunity to learn more about the actual workings of large scale power systems and converters as well as apply control techniques to real systems. I did a variety of tasks in the design and analysis of power electronics and their control systems. I worked on a variety of projects in support of the different divisions in our role as a research group, but primarily solar energy and naval applications.

Solar Inverters

My main responsibility during my last 2 years at GE was the design, control, and deployment of utility-scale solar inverters. These systems convert DC power from photovoltaic arrays to the AC power required on the power grid. There is a large range of plant power levels, from a few kilowatts on residential rooftops, to hundreds of Megawatts. My focus is inverters on the high end of that spectrum, above 1MW, which typically goes in plants above 30 MW. The largest plant is about 400MW. I led the design team that created the world's largest operating solar inverter (4MW / 1500Vdc). The controls portion is particularly interesting because plants of that scale have a significant impact on the power grid.

Ship Electrification

USS Arleigh Burke, DDG-51
USS Arleigh Burke, DDG-51.

I studed various issues around the electric propulsion and power systems of naval and merchant vessels including system-level integration, supervision, and control issues, as well as mechanical and electrical design work. 

Shipboard power systems exhibit many of the same characteristics of other interesting energy systems like hybrid vehicles, microgrids, and renewables. The propulsion load is typically at least as large as the ship "hotel" load (everything else), and often much larger for all-electric propulsion. The ship electric grid is much smaller than a typical power system and thus exhibits relatively low inertia and "stiffness." All this means the propulsion plays a major role in the stability of the electric system. In addition, the propulsion uses variable-speed drives, which means that a major component of the system power is based on power electronics. This generates a different class of stability problems than is encountered in traditional power systems, although high penetrations of renewables will create these same issues.

GE is a major supplier of electric propulsion for commercial and military vessels, and including US Navy electric propulsion (T-AKE Class, LHD-8, DDG-1000).

My most recent project was acting as technical lead on a large ($1.5M) project to study shipboard optimal power system control. The project team included the GE Global Research Center, the University of Michigan, and Purdue University, with 10 faculty or industry members and 7 students.


I have also worked on a variety of other projects including passive filters for industrial drives and STATCOMs (a power electronic device) to stabilize the power system voltage at an arc furnace.

ARC Furnace Picture
An arc furnace

A wind turbine

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