Resume

Education

PhD Indian Institute of Technology Bombay 2007 - 2011
Master of Technology Indian Institute of Technology Kanpur 2002 - 2004
Bachelor of Engineering Mumbai University 1998 - 2002

Industrial Experience

Research Engineer, Power Conversion and Safety Lab, GE Global Research Centre, John F. Welch Technology Centre, Bangalore, INDIA November 2010 to July 2012
Projects: Feasibility studies, control design and experimental verification of converters for wind generators, Uninterruptible Power Supplies (UPS) and electric vehicle chargers.
Associate Scientist, Control and Optimization Group, Research Division, ABB Global Industries and Services Ltd., Bangalore, INDIA. January 2010 to November 2010
Project: Real-time simulation of power plants for advanced load-shedding techniques.

Academic Experience

Postdoctoral research topic Control and Interfaces for Urban Clean Energy Microgrids
Duration September 2012 to May 2015

  • The industry sponsors (utility operators) wish to examine the impacts of connection of renewable energy sources (wind and PV) into the distribution system. One of their prime interests has been to develop models for the fluctuation of voltage particularly in weaker parts of the distribution system that may cause malfunctioning of loads used by rural customers. A mathematical model has been developed as a design and offline analytical tool that will enable the system operators to examine with accuracy the fluctuation of voltage caused by renewable energy sources. Subsequently, by offering solutions such as energy storage and reactive power compensation in combination with renewable sources in the form of a microgrid, methods of mitigating voltage fluctuations have been proposed.
  • The mathematical model proposed has been verified using simulations in MATLAB/Simulink. Furthermore, a 12 kVA, 208V laboratory prototype of a microgrid has been developed. This microgrid is comprised of four ac-dc-ac power electronic converters that emulate the grid, the renewable energy source, the energy storage system and the rural load. Therefore, with this prototype, the effects of renewable energy sources on the distribution system can be examined dynamically and in real-time while at the same time verifying the effectiveness of the energy storage control techniques.

PhD Thesis Topic Stability and Operational Issues in the Decentralized Control of Multi-Inverter Microgrids
Duration January 2007 to March 2011

  • An isolated microgrid without an electrical connection to a main grid is formed by multiple three-phase inverters. These inverters share multiple loads within the microgrid by emulating synchronous generators by active power - voltage frequency and reactive power - voltage magnitude droop control. This method of control results in decentralized operation of the microgrid, whereby the inverters share the load without high-bandwidth communication or a supervisory control. The study was performed using simulations in C++/Scilab and experimental verification by fabricating an isolated three-phase microgrid of 140V, 2.5 kVA formed by three inverters.
  • The major contribution of this thesis was to propose a mathematical framework to analyse the stability of multi-inverter microgrids controlled in a decentralized manner with droop control laws.

Master's Thesis Topic Application of Three-Phase Four-wire Active Filter for Shunt and Series Compensation in Three-Phase Four-wire Systems with Non-ideal Supply
Duration August 2002 to July 2004

  • The proliferation of modern energy-efficient loads such as fluorescent lamps and variable speed drives results in harmonic pollution in the distribution system. The harmonic pollution manifests itself in the form of non-sinusoidal currents in the feeders containing harmonics or non-sinusoidal voltages at the buses. Harmonic content in feeder currents causes greater losses, derating of feeder capacity and excessive transformer losses. Harmonic content in the bus voltages causes malfunctioning of sensitive equipment connected to the buses. To avoid these ill-effects, two reported solutions were considered - shunt compensation using Distribution STATic COMpensators (DSTATCOMs) or series compensation using Dynamic Voltage Compensators (DVRs).
  • The major contribution of the thesis was to formulate algorithms and operating strategies for operation under unbalanced conditions in three-phase four-wire systems.


Publications

Journal Publications

  1. S. Iyer, B. Wu, Y. Li, B. Singh, "A mathematical model to predict voltage fluctuations in a distribution system with renewable energy sources," Accepted for publication in the International Journal of Emerging Electric Power Systems.
  2. S. Iyer, M. Belur, and M. Chandorkar, "A generalized computational method to determine stability of a multi inverter microgrid," IEEE Transactions of Power Electronics, Vol. 25, Issue 9, pp 2420-2432, September 2010.
  3. S. Iyer, M. Belur, and M. Chandorkar, "Analysis and mitigation of voltage offsets in multi inverter microgrids," IEEE Transactions of Energy Conversion, Vol. 26, Issue 1, pp 354-363, March 2011.
  4. S. Iyer, A. Ghosh, and A. Joshi, "Inverter topologies for DSTATCOM applications - a simulation study," Electric Power Systems Research, Vol. 75, Issues 2-3, pp 161-170, August 2005.

Conference Publications

  1. S. Iyer, B. Wu, Y. Li, B. Singh, "Asymmetrical fault ride-through of three-phase PV systems using four-wire dc-ac converters," Proceedings of the 2014 International Power Electronics Conference (ECCE-Asia), Hiroshima, Japan, pp. 3482-3488, May 2014.
  2. S. Iyer, M. Belur, and M. Chandorkar, "Application of graph theory in stability analysis of meshed microgrids," in Proceedings of the 19th Symposium of Mathematical Theory of Networks and Systems, Budapest, Hungary, July 2010.
  3. S. Iyer, M. Belur, and M. Chandorkar, "Decentralized control of a line interactive Uninterruptible Power Supply (UPS)," in Proceedings of the American Control Conference 2010, Baltimore, USA, June/July 2010.
  4. S. Iyer, and M. Chandorkar, "Controller design for a voltage source inverter with LC filter using frequency response characteristics," in Proceedings of the Third National Power Electronics Conference, IISc Bangalore, Bangalore, India, 17-19 December 2007.
  5. S. Iyer, A. Ghosh, and A. Joshi, "Main system and microgrid support using a distributed generator through back-to-back inverters," in Proceedings of the IEEE International Conference on Industrial Technology, Mumbai, India, pp. 299-304, 15-17 December 2006.
  6. S. Iyer, A. Ghosh, and A. Joshi, "Power flow control in a distribution system through an inverter interfaced distributed generator," in Proceedings of the IEEE Power Engineering Society General Meeting, Montreal, Quebec, Canada, 18-22 June 2006.
  7. S. Iyer, A. Ghosh, and A. Joshi, "Shunt compensation in three-phase four-wire distribution system with non-ideal supply," in Proceedings of Second National Power Electronics Conference, IIT Kharagpur, India, pp. 167-170, 22-24 December 2005.
  8. S. Iyer, A. Ghosh, and A. Joshi, "Operation of controlled rectifier supported dynamic voltage regulator," in Proceedings of the IEEE Power Engineering Society General Meeting 2005, San Francisco, CA, USA, pp. 1475-1481, 12-16 June 2005.
  9. S. Iyer, A. Ghosh, and A. Joshi, "Comparison of inverter topologies for the dynamic voltage regulator (DVR)," in Proceedings of Thirteenth National Power Systems Conference, IIT Madras, India, Vol 1., pp. 584-588, 27-30 December 2004.