Kevin D Bachovchin

Advisor(s):

Marija Ilic, Jim Hoburg

Research Project Description:
My research focuses on designing nonlinear power electronic control for using flywheel energy storage systems for transient stabilization of electric power systems in response to large sudden wind power disturbances.  There is much interest in implementing more wind power plants and other renewable energy sources in future power grids.   However, because wind power is unpredictable and difficult to control, large sudden disturbances in wind power generation can cause high deviations in frequency and voltage or even transient instabilities.  To address these concerns, one possible solution is to add fast energy storage, such as flywheels, which can respond faster than conventional generators and can stabilize the system until slower generators can respond. 

Power electronic control is designed so that when there is a wind power disturbance, the flywheel absorbs the disturbance and the rest of the system is minimally affected.  Switches in the power electronics interfacing between the flywheel and the rest of the power grid are controlled in order to regulate both the flywheel speed and the power electronic currents.  The controller uses time-scale separation and nonlinear passivity-based control logic.

Due to the complex nature of large interconnected power systems, my research also involves implementing computer-aided automated methods for both the modeling and control of power systems.  An automated method was designed for symbolically deriving the dynamic model of power systems using the Lagrangian formulation from classical mechanics, where the model is derived from the physical energy functions of the system.  Another automated approach was implemented for symbolically deriving the control law using passivity-based control logic, where the control law is derived from desired closed-loop energy functions. 

Finally, my research also focuses on designing passive magnetic bearings for flywheels.  Magnetic bearings can be used in flywheels instead of conventional mechanical bearings in order to reduce frictional energy losses, but a significant challenge with passive magnetic bearings results from Earnshaw’s Theorem, which states the impossibility of stably levitating a rotor in all directions using any configuration of only permanent magnets or fixed currents.  To overcome this instability, I designed and modeled a Halbach array stabilizer, which, if the flywheel is displaced from the equilibrium, induces currents in stabilization coils in order to provide a net restoring force on the flywheel.  The resultant magnetic fields and forces of the magnetic bearing system are computed using electromagnetic theory, demonstrating that stable levitation of the flywheel in all directions is achieved with this design.

Research Interests: energy storage, flywheels, power electronics, power system dynamics, nonlinear control, electromagnetics, electromechanics, magnetic levitation

Publications:

Conference Publications:

M. Wagner, K. Bachovchin, M. Ilic, "Computer Architecture and Multi Time-Scale Implementations for Smart Grid in a Room Simulator," 9th IFAC Symposium on Control of Power and. Energy Systems (CPES), New Delhi, India, December 2015.

K. Bachovchin, M. Ilic, "Transient Stabilization of Power Grids Using Passivity-Based Control with Flywheel Energy Storage Systems," IEEE Power & Energy Society General Meeting, Denver, USA, July 2015.

M. Ilic, K. Bachovchin, M. Cvetkovic, X. Miao, "Physics-Based Foundations for Cyber and Market Design in Complex Electric Energy Systems," 53rd IEEE Conference on Decision and Control, Los Angeles, USA, December 2014. 

M. Ilic, M. Cvetkovic, K. Bachovchin, Q. Liu, "Modeling, Analysis and Control Design Complexities in Future Electric Energy Systems," 15th International IEEE Power Electronics and Motion Control Conference and Exposition, Novi Sad, Serbia, September 2012. 

M. D. Ilić, M. Cvetković, K. D. Bachovchin, A. Hsu, “Toward a Systems Approach to Power-Electronically Switched T&D Equipment at Value,” IEEE Power & Energy Society General Meeting, Detroit, USA, July 2011.

K. D. Bachovchin, M. D. Ilić, A. S. Lewis, "Costs and benefits of transmission congestion management," IEEE Power Systems Conference and Exposition (PSCE), Phoenix, USA, March 2011.

Journal Publications:

K. D. Bachovchin, M. D. Ilić, "Automated Modeling of Power System Dynamics Using the Lagrangian Formulation," International Transactions on Electrical Energy Systems [to appear, 2014]

K. D. Bachovchin, J. F. Hoburg, R. F. Post, “Stable Levitation of a Passive Magnetic Bearing,” IEEE Transactions on Magnetics, vol.49, no.1, pp.609-617, Jan. 2013.

K. D. Bachovchin, J. F. Hoburg, R. F. Post, “Magnetic Fields and Forces in Permanent Magnet Levitated Bearings,” IEEE Transactions on Magnetics, vol.48, no.7, pp.2112-2120, July 2012.

Book Chapters:

K. D. Bachovchin, M. Cvetković, M. D. Ilić, “Transient Stabilization in Systems with Wind Power”, Chapter 19 in "Engineering IT Enabled Electricity Services: The Case of Low Cost Green Azores Islands", Springer, 2013

Theses:

K. D. Bachovchin, “Magnetic Fields and Forces in an Ambient Temperature Passive Magnetically Levitated Bearing System”, M.S. dissertation, Carnegie Mellon University, PA, 2011.

K. D. Bachovchin, "Design, Modeling, and Power Electronic Control for Transient Stabilization of Power Grids Using Flywheel Energy Storage Systems," Ph.D. dissertation, Carnegie Mellon University, PA, 2015

Submitted Publications:

K. D. Bachovchin, M. D. Ilić, "Passivity-Based Control Using Three Time-Scale Separations of Variable Speed Drives for Flywheel Energy Storage Systems," EESG Working Paper No. R-WP-6-2015, October 2014. (submitted to International Federation of Automatic Control)

K. D. Bachovchin, M. D. Ilić, "Automated Computer-Aided Symbolic Derivation of Passivity-Based Control Law for Electrical Systems and Demonstration on Three-Phase AC/DC/AC Converter," EESG Working Paper No. R-WP-5-2014, August 2014. (submitted to IEEE Transactions on Control Systems Technology)

Awards/Fellowships:

ECE Ph.D. Sack Fellowship: 2010
Bachelor of Science University Honors: May 2010
Dean’s List, Carnegie Institute of Technology: Spring 2007, Spring 2008, Fall 2009, Spring 2010

Personal Webpage: http://www.andrew.cmu.edu/user/kbachovc/

CV: https://docs.google.com/file/d/0Bz-xXy66I5W3LTFTdnVkajdSMEU/edit?pli=1