Remarkable research of Dr. Tousif Khan N is honoured with APJ Abdul Kalam Memorial International Travel Award

SRM University AP, Andhra Pradesh faculty, Dr. Tousif Khan N, Assistant Professor and Head of the Department, Department of Electrical and Electronics Engineering, is to present a paper “Laguerre Neural Network Driven Adaptive Control of DC-DC Step Down Converter” in the renowned International Federation for Automatic Control (IFAC) World Congress to be held in Germany during July 12-17, 2020. Further this research article is also selected for the prestigious APJ Abdul Kalam Memorial International Travel Award by the Automatic Control and Dynamic Optimization Society (ACDOS) chaired by Professor Ravi Gudi of Indian Institute of Technology Bombay.

The research work of Dr. Tousif proposes a novel Laguerre neural network estimation technique for the approximation of unknown and uncertain load function, followed by its subsequent compensation in the adaptive backstepping controller. A detailed design of the proposed estimator and adaptive backstepping controller along with closed loop asymptotic stability have been presented. Further, the proposed control mechanism is evaluated through extensive numerical simulations while subjecting the converter to input voltage, reference voltage, and load resistance perturbations. Furthermore, the results are verified by testing the proposed controller on a laboratory prototype with DSP based TM320F240 controller board. The analysis of results reveals that the proposed control methodology for DC-DC step down converter offers a faster transient output voltage tracking with smooth and satisfactory inductor current response over a wide operating range. Dr. Tousif informs, “Under the class of DC-DC converters, the dynamics of DC-DC step down converter are nonlinear in nature and are largely influenced by both parametric and unanticipated external perturbations. In its closed loop operation, obtaining a precise output voltage tracking besides satisfactorily inductor current response is a challenging control objective. Hence, in this regard, this article proposes a solution.”

Electric power supply is the principal entity behind any electrical circuits and systems. Irrespective of their function in the digital domain, these circuits necessarily require a reliable and efficient energy source for their operations. Among the two existing forms of electrical energy, namely, the direct current (DC) and the alternating current (AC), the DC power finds wide use in numerous applications in the field of telecommunication, instrumentation, medical electronics, aerospace, defence and power transmission.

Ever since the fundamental innovations in DC systems by Thomas Alva Edison in 1880, DC rectification, and modulation method have remained central to various utilities. During the initial years, DC power conversion primarily resorted to the use of vacuum tube technology in delivering a desirable level of voltage from an AC source. The rectification stage was subsequently followed by filtering of the voltage at the output end. Nonetheless, the vacuum tube technology supported very low current density and featured a high ripple content in the DC voltage. Additionally, the output voltage was inconsistent or rather unregulated, making it inappropriate for DC power operated electrical and electronic systems. Much later in 1967, integrated series regulators were developed which eventually became popular as linear power supplies (LPS). Such a classical DC power generation method involved an AC transformer, AC-DC rectifier, and a voltage regulator in its assembly. The transistors in LPS operate under active region and dissipate large amounts of heat due to the voltage drop while high current flows through the collector-emitter junction, thereby causing substantial power loss and a very low energy efficiency. Even though they characterize the low level of noise and find better suitability in audio applications, yet their critical limitations of huge size, heavy weight and high cost make them infeasible for use in portable electronic devices.

In tandem to these aforementioned developments, the advancements in power semiconductor technology led to the invention of low cost reliable power switches exhibiting fast switching response. This proved to be instrumental in building an energy efficient switched mode power supply which gradually gained popularity. “Its impact on electrical technology was phenomenal, replacing conventional linear voltage supplies with switched mode power supplies giving rise to enhanced efficiency, light weight, compactness, and comparably lower cost. Such a modern DC conversion system primarily includes DC-DC converters, wherein the rectified input voltage is fed to the DC-DC converter circuits for obtaining specific voltage levels. The primary objective in DC-DC converters is to transfer the energy among different DC circuits functioning at a specific voltage and current levels. This process of energy transfer is performed by temporarily storing the energy from the input source in an operating mode, followed by releasing it in the other operational mode of the converter. Thus, one level of DC input voltage is converted to another level of average DC output voltage at the load end. Meanwhile, the converter being ideal is expected to consume no energy. Any consumption of energy in the converter interface amounts to direct power loss in the overall supply system. Typically, converters render high input-output conversion.”, enlightens Dr. Tousif Khan N. His notable research work offers to mitigate these issues, leading to the venerated APJ Abdul Kalam Memorial International Travel Award. Advancing his work in the future, Dr. Tousif will be closely working on the society’s activities with ACDOS as a member for mutual benefit.

Dr Tarkeshwar Mahto, Assistant Professor, in the Department of Electrical and Electronics Engineering has published a paper titled “Design and Implementation of Frequency Controller for Wind Energy-Based Hybrid Power System Using Quasi-Oppositional Harmonic Search Algorithm” in the reputed research journal, Energies.

An innovative union of fuzzy controller and proportional-integral-derivative (PID) controller under the environment of fractional order (FO) calculus is described in the present study for an isolated hybrid power system (IHPS) in the context of load frequency control. The proposed controller is designated as FO-fuzzy PID (FO-F-PID) controller. The undertaken model of IHPS presented here involves different independent power-producing units, a wind energy-based generator, a diesel engine-based generator and a device for energy storage (such as a superconducting magnetic energy storage system). The selection of the system and controller gains was achieved through a unique quasi-oppositional harmony search (QOHS) algorithm. The QOHS algorithm is based on the basic harmony search (HS) algorithm, in which the combined concept of quasi-opposition initialization and HS algorithm fastens the profile of convergence for the algorithm. The competency and potency of the intended FO-F-PID controller were verified by comparing its performance with three different controllers (integer-order (IO)-fuzzy-PID (IO-F-PID) controller, FO-PID and IO-PID controller) in terms of deviation in frequency and power under distinct perturbations in load demand conditions. The obtained simulation results validate the cutting-edge functioning of the projected FO-F-PID controller over the IO-F-PID, FO-PID and IO-PID controllers under non-linear and linear functioning conditions. In addition, the intended FO-F-PID controller, considered a hybrid model, proved to be more robust against the mismatches in loading and the non-linearity in the form of rate constraint under the deviation in frequency and power front.

The research group believes that the study will boost the use of renewable energy utilization for fulfilling energy requirements in a more reliable and stable manner. In future, they plan to use the knowledge gained from the isolated systems to develop a Multi-Migrigrid system.

Collaborations:

1. Department of Electrical and Electronics Engineering, M S Ramaiah Institute of Technology, Bengaluru 560054, India
2. The Berkeley Education Alliance for Research in Singapore, The National University of Singapore, Singapore 138602, Singapore
3. Clean and Resilient Energy Systems (CARES) Lab, Texas A&M University, Galveston, TX 77553, USA;
4. Department of Electrical Engineering, College of Engineering, Taif University, Taif 21944, Saudi Arabia