Prasanta  Sarkar, Mrinal Kanti  Sarkar, Subrata  Banerjee, 
    Delta Operator Modelling and Control of Electromagnetic Levitation System,
    International Journal of Electrical and Power Engineering,
    Volume 4,Issue 2,
    2010,
    Pages 90-95,
    ISSN 1990-7958,
    ijepe.2010.90.95,
    (https://makhillpublications.co/view-article.php?doi=ijepe.2010.90.95)
    Abstract: The dynamic model develop from physical relationship of an Electro Magnetic Levitation System (EMLS) is considered in this study to propose a unified framework for controller design. The EMLS is discretised using delta operator. The delta operator representation is implicitly discrete-time formulation which converges to its continuous-time counterparts at high sapling frequency. The EMLS is inherently unstable and strongly non-linear in nature which is linearised and different classical control scheme such as PD, Lead, Lag-lead, PID and combination of PI and Lead compensators are designed to meet the requirement of the overall controlled system stability and performance. The simulation results exhibit the usefulness of the proposed schemes.
    Keywords: lag-lead;lead;electromagnetic levitation system;unified approach;Delta operator;PID;PI plus lead control;India