Designing active multi port circuits with high bandwidth is an important practical problem of Electrical Engineering. The challenges in such a design are posed by uncertainties in the response of circuits arising from high frequency behavior and tolerances and variation of parameters between those used during design calculation and the actual circuit after manufacture. Hence the performance of a fabricated chip or the circuit differs from that of the designed circuit and is the reason why fabricated circuits need compensation in actual use. This problem appears to be analogous to a feedback control design problem. However it was never addressed seriously by Control theorists nor was the circuit design community aware of the modern developments in Control theory most relevant for this problem. This talk describes the attempts by the speaker in addressing this problem and further scope of this direction of research for application in Electrical systems. The central theme of the research is based on solving the problem of stabilization of active multi port networks by compensation at the ports. The existing feedback control formulation could not be utilized for this problem due to lack of a signal flow graph structure of interconnection of networks at ports. The problem was however solved using the coprime factorization theory in representing the networks and the resulting equations due to port interconnections along with Kirchoff's laws. The problem of sensitivity and robust stabilization are solved using this approach which provides new alternatives to design of compensation. Much further scope exists in developing this approach for designing controls in electrical systems from 50Hz to RF.
Virendra Sule did his Ph.D. from this department in 1990. After a short stint at a DRDO lab he joined as faculty in dept. of EE at IIT Kanpur and later at dept. of EE at IIT Bombay in 1999. From 2006 till 2009 he worked with the Computational Research Laboratory (a startup of Tata Sons) at Pune and worked on Information Security and High Performance Computing. Next one year he worked as a Visiting Professor at C.R.Rao Advanced Institute of Mathematics, Statistics and Computer Science and eventually joined this department again in 2010.