Dr Govindaraj Thangavel - Academia.edu (original) (raw)

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Papers by Dr Govindaraj Thangavel

This project presents an intelligent speed controller for BLDC motor, based on a single artificia... more This project presents an intelligent speed controller for BLDC motor, based on a single artificial neuron. Artificial neural network-based motor controllers require no offline training, which is both time consuming and requires extensive knowledge of motor behavior for the specific drive system. In addition, drive behavior is measured with the help of Back Emf sensing. This method of Back Emf sensing is used for providing the controlled gate pulse to the MOSFET switches. In existing method used Hall Sensor. The proposed drive system overcomes the limitations of Hall Sensors using back Emf control and using ANN control algorithm, is robust under varying operating parameters, and is easily adaptable to various drive systems. Drive efficiency is verified in simulation as well as experimentally.

Power dissipation has become an important factor in integrated circuits fabrication due to the ra... more Power dissipation has become an important factor in integrated circuits fabrication due to the rapid increase of battery powered hand held devices. In particular static dissipation increases considerably as technology scales down. To extend the battery lifetime of portable devices and ensure proper operation of digital circuits, static dissipation reduction needs to be addressed. In this paper, a low leakage charge recycling technique is proposed for this concern. The simulation results reveal that this technique exhibits 74 % leakage reduction, 37 % ground bounce reduction, 58 % Power Delay Product (PDP) reduction and nearly 10-33 % improvement in noise margin compared to conventional technique.

In this paper the development, finite element analysis(FEA) and electronic control of an axial fl... more In this paper the development, finite element analysis(FEA) and electronic control of an axial flux permanent magnet linear oscillating motor (PMLOM) suitable for short strokes is described. The forces for aluminium mover embedded with rare earth permanent magnets are determined analytically through finite element method. A microcontroller based inverter is developed for the control of thrust and oscillation frequency. The PMLOM can perform precision oscillation task with relatively low power dissipation. The use of powerful permanent magnet material such as Neodymium-Iron-Boron alloys has greatly improved the performance of the machine. Simulation and suitable experiments are in good agreement to the theoretical calculations.

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2016

Numerous studies have been presented to eliminate dead-time effect. This paper will present a dea... more Numerous studies have been presented to eliminate dead-time effect. This paper will present a dead-time elimination scheme for a sinusoidal pulse width modulation (SPWM) controlled inverter. In comparison to using expensive current sensor, this method precisely determine the load current polarity by detecting the terminal voltage of the antiparallel diode of power devices. The presented scheme includes the freewheeling current polarity detection circuit and the PWM control generator without dead-time. This method significantly reduces the output voltage loss and current distortion. Simulation results are given to demonstrate the effectiveness of the dead-time elimination scheme. Index Terms –Dead time elimination, sinusoidal pulse width modulation (SPWM) and Anti parallel diode.

— Several well-known analytical techniques exist for the force profile analysis of permanent-magn... more — Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear oscillating motors (PMLOMs). These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this from the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The objective of this paper is to determine the forces for aluminium mover embedded with Nd-Fe-B Rare Earth Permanent Magnet experimentally and analytically thr...

Several well-known analytical techniques exist for the force profile analysis of permanent-magnet... more Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear oscillating motors (PMLOMs). These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this from the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The objective of this paper is to determine the forces for aluminium mover embedded with Nd-Fe-B Rare Earth Permanent Magnet experimentally and analytically throu...

A general framework for the development of a new generation of PM linear oscillating machine (PML... more A general framework for the development of a new generation of PM linear oscillating machine (PMLOM) using FE magnetic analysis suitable for short strokes is described in this paper. A microcontroller based IGBT inverter is developed for the control of thrust and oscillation frequency. The PMLOM can perform precision oscillation task with relatively low power dissipation. The use of powerful permanent magnet material such as Neodymium- Iron-Boron alloys has greatly improved the performance of the machine. The forces for aluminium mover embedded with rare earth permanent magnets are determined analytically and the results are validated extensively by comparison with finite element analyses. INEAR motors are finding increasing applications in different specific areas like high-speed transport, electric hammers, looms, reciprocating pumps, artificial heart pump, etc. (1)-(7). They are also well suited for manufacturing automation applications. Therefore, design of energy efficient and ...

Security and protection of private user information are a prerequisite for the deployment of the ... more Security and protection of private user information are a prerequisite for the deployment of the mobile network technologies. Nevertheless, the establishment of secure communication architecture within mobile ad hoc networks addresses special challenges, due to the characteristic and specific cities of such environment (high dynamic and mobility of nodes, high rate of topology changes, high variability in nodes density and neighborhood, broad-cast/geo-cast communication nature). A number of secure authentication schemes based on asymmetric cryptography have been proposed to prevent such attacks. In this paper, we address someinteresting issues arising in such MANETs by designing an anonymous routing framework (ALERT) extended to key server management and digital signature algorithm. It uses nodes' current locations to construct a secure MANET map. Based on the current map, each node can decide which other relay nodes it wants to communicate with. ALERT takes advantage of some advanced cryptographic primitives to achieve node authentication, data integrity, anonymity and intractability (tracking-resistance). It also offers resistance to certain insider attacks.resistance). It also offers resistance to certain insider attacks.

A B ST R A C T A general framework for the development of a new generation of PM Linear Oscillati... more A B ST R A C T A general framework for the development of a new generation of PM Linear Oscillating Machine (PMLOM) using FE magnetic analysis suitable for short strokes is described in this paper. A microcontroller based IGBT inverter is developed for the control of thrust and oscillation frequency. The PMLOM can perform precision oscillation task with relatively low power dissipation. The use of powerful permanent magnet material such as Neodymium-Iron-Boron alloys has greatly improved the performance of the machine. The forces for aluminium mover embedded with rare earth permanent magnets are determined analytically and the results are validated extensively by comparison with finite element analyses.

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES

Static power has become the most important factor in the fabrication of integrated circuits. Powe... more Static power has become the most important factor in the fabrication of integrated circuits. Power gating techniques minimize leakage currents and help to develop ultra-low-power and high-performance digital circuits. In this paper, a power gating approach is proposed to minimize leakage for subnanometer technologies. Simulation results reveal that the proposed technique reduces maximum of 96% leakage power, 33% dynamic power, 49% drowsy power, and 16% energy as compared to conventional techniques. The proposed technique offers good leakage reduction, even under variation of different operating parameters.

In this paper, a new single-phase, five-level inverter topology with a single-dc source is presen... more In this paper, a new single-phase, five-level inverter topology with a single-dc source is presented. The proposed topology is obtained by cascading a three-level flying capacitor inverter with a flying H-bridge power cell. This topology has redundant switching states for generating different pole voltages. By selecting appropriate switching states, the capacitor voltages can be balanced instantaneously (as compared to the fundamental) in any direction of the current, irrespective of the load power factor. Another important feature of this topology is that if any H-bridge fails, it can be bypassed and the configuration can still operate as a three-level inverter at its full power rating. This feature improves the reliability of the circuit. A induction motor is run with the proposed topology for the full modulation range. The effectiveness of the capacitor balancing algorithm is tested for for the full range of speed and during the sudden acceleration of the motor. Index Terms—Flyin...

The design, analysis, and control methodology of an energy efficient and high force to weight rat... more The design, analysis, and control methodology of an energy efficient and high force to weight ratio rare earth N42 NdFeB based permanent magnet linear oscillating motor has been described. For this axial flux machine the mover is consisting of Aluminium structure embedded with rare earth permanent magnets of high energy density. Microcontroller based drive is developed for frequency and thrust control of the machine. Finite element method using FEMM is employed for analysis of various performance parameters of machine. The same parameters are also compared with the measured ones, which yields a good agreement to the proposed design.

To guarantee a good productivity and a better quality of the industrial systems, it is necessary ... more To guarantee a good productivity and a better quality of the industrial systems, it is necessary to know the evolution of its various parameters but also its operation mode. The main goal of this work is to carry out a study to improve a flatness control in a reversing cold rolling mill, precisely the web winding system part. We designate by a winding process any system applying the cycles of unwinding, transport, treatment and winding to various flat products. This system knows several constraints such as the thermal effects caused by the frictions, and the mechanical effects provoked by metal elongation, that generates dysfunctions due to the influence of the process conditions. For this installations type, the various automatisms functions, often very advanced, are realized in modular systems with distributed architecture. Our main goal is to obtain a precise thickness, with the best possible regularity. With this intention, we are preceded to the modelling and the control of the nonlinear dynamic behaviour of a web winding process.

This project presents an intelligent speed controller for BLDC motor, based on a single artificia... more This project presents an intelligent speed controller for BLDC motor, based on a single artificial neuron. Artificial neural network-based motor controllers require no offline training, which is both time consuming and requires extensive knowledge of motor behavior for the specific drive system. In addition, drive behavior is measured with the help of Back Emf sensing. This method of Back Emf sensing is used for providing the controlled gate pulse to the MOSFET switches. In existing method used Hall Sensor. The proposed drive system overcomes the limitations of Hall Sensors using back Emf control and using ANN control algorithm, is robust under varying operating parameters, and is easily adaptable to various drive systems. Drive efficiency is verified in simulation as well as experimentally.

Power dissipation has become an important factor in integrated circuits fabrication due to the ra... more Power dissipation has become an important factor in integrated circuits fabrication due to the rapid increase of battery powered hand held devices. In particular static dissipation increases considerably as technology scales down. To extend the battery lifetime of portable devices and ensure proper operation of digital circuits, static dissipation reduction needs to be addressed. In this paper, a low leakage charge recycling technique is proposed for this concern. The simulation results reveal that this technique exhibits 74 % leakage reduction, 37 % ground bounce reduction, 58 % Power Delay Product (PDP) reduction and nearly 10-33 % improvement in noise margin compared to conventional technique.

In this paper the development, finite element analysis(FEA) and electronic control of an axial fl... more In this paper the development, finite element analysis(FEA) and electronic control of an axial flux permanent magnet linear oscillating motor (PMLOM) suitable for short strokes is described. The forces for aluminium mover embedded with rare earth permanent magnets are determined analytically through finite element method. A microcontroller based inverter is developed for the control of thrust and oscillation frequency. The PMLOM can perform precision oscillation task with relatively low power dissipation. The use of powerful permanent magnet material such as Neodymium-Iron-Boron alloys has greatly improved the performance of the machine. Simulation and suitable experiments are in good agreement to the theoretical calculations.

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2016

Numerous studies have been presented to eliminate dead-time effect. This paper will present a dea... more Numerous studies have been presented to eliminate dead-time effect. This paper will present a dead-time elimination scheme for a sinusoidal pulse width modulation (SPWM) controlled inverter. In comparison to using expensive current sensor, this method precisely determine the load current polarity by detecting the terminal voltage of the antiparallel diode of power devices. The presented scheme includes the freewheeling current polarity detection circuit and the PWM control generator without dead-time. This method significantly reduces the output voltage loss and current distortion. Simulation results are given to demonstrate the effectiveness of the dead-time elimination scheme. Index Terms –Dead time elimination, sinusoidal pulse width modulation (SPWM) and Anti parallel diode.

— Several well-known analytical techniques exist for the force profile analysis of permanent-magn... more — Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear oscillating motors (PMLOMs). These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this from the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The objective of this paper is to determine the forces for aluminium mover embedded with Nd-Fe-B Rare Earth Permanent Magnet experimentally and analytically thr...

Several well-known analytical techniques exist for the force profile analysis of permanent-magnet... more Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear oscillating motors (PMLOMs). These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this from the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The objective of this paper is to determine the forces for aluminium mover embedded with Nd-Fe-B Rare Earth Permanent Magnet experimentally and analytically throu...

A general framework for the development of a new generation of PM linear oscillating machine (PML... more A general framework for the development of a new generation of PM linear oscillating machine (PMLOM) using FE magnetic analysis suitable for short strokes is described in this paper. A microcontroller based IGBT inverter is developed for the control of thrust and oscillation frequency. The PMLOM can perform precision oscillation task with relatively low power dissipation. The use of powerful permanent magnet material such as Neodymium- Iron-Boron alloys has greatly improved the performance of the machine. The forces for aluminium mover embedded with rare earth permanent magnets are determined analytically and the results are validated extensively by comparison with finite element analyses. INEAR motors are finding increasing applications in different specific areas like high-speed transport, electric hammers, looms, reciprocating pumps, artificial heart pump, etc. (1)-(7). They are also well suited for manufacturing automation applications. Therefore, design of energy efficient and ...

Security and protection of private user information are a prerequisite for the deployment of the ... more Security and protection of private user information are a prerequisite for the deployment of the mobile network technologies. Nevertheless, the establishment of secure communication architecture within mobile ad hoc networks addresses special challenges, due to the characteristic and specific cities of such environment (high dynamic and mobility of nodes, high rate of topology changes, high variability in nodes density and neighborhood, broad-cast/geo-cast communication nature). A number of secure authentication schemes based on asymmetric cryptography have been proposed to prevent such attacks. In this paper, we address someinteresting issues arising in such MANETs by designing an anonymous routing framework (ALERT) extended to key server management and digital signature algorithm. It uses nodes' current locations to construct a secure MANET map. Based on the current map, each node can decide which other relay nodes it wants to communicate with. ALERT takes advantage of some advanced cryptographic primitives to achieve node authentication, data integrity, anonymity and intractability (tracking-resistance). It also offers resistance to certain insider attacks.resistance). It also offers resistance to certain insider attacks.

A B ST R A C T A general framework for the development of a new generation of PM Linear Oscillati... more A B ST R A C T A general framework for the development of a new generation of PM Linear Oscillating Machine (PMLOM) using FE magnetic analysis suitable for short strokes is described in this paper. A microcontroller based IGBT inverter is developed for the control of thrust and oscillation frequency. The PMLOM can perform precision oscillation task with relatively low power dissipation. The use of powerful permanent magnet material such as Neodymium-Iron-Boron alloys has greatly improved the performance of the machine. The forces for aluminium mover embedded with rare earth permanent magnets are determined analytically and the results are validated extensively by comparison with finite element analyses.

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES

Static power has become the most important factor in the fabrication of integrated circuits. Powe... more Static power has become the most important factor in the fabrication of integrated circuits. Power gating techniques minimize leakage currents and help to develop ultra-low-power and high-performance digital circuits. In this paper, a power gating approach is proposed to minimize leakage for subnanometer technologies. Simulation results reveal that the proposed technique reduces maximum of 96% leakage power, 33% dynamic power, 49% drowsy power, and 16% energy as compared to conventional techniques. The proposed technique offers good leakage reduction, even under variation of different operating parameters.

In this paper, a new single-phase, five-level inverter topology with a single-dc source is presen... more In this paper, a new single-phase, five-level inverter topology with a single-dc source is presented. The proposed topology is obtained by cascading a three-level flying capacitor inverter with a flying H-bridge power cell. This topology has redundant switching states for generating different pole voltages. By selecting appropriate switching states, the capacitor voltages can be balanced instantaneously (as compared to the fundamental) in any direction of the current, irrespective of the load power factor. Another important feature of this topology is that if any H-bridge fails, it can be bypassed and the configuration can still operate as a three-level inverter at its full power rating. This feature improves the reliability of the circuit. A induction motor is run with the proposed topology for the full modulation range. The effectiveness of the capacitor balancing algorithm is tested for for the full range of speed and during the sudden acceleration of the motor. Index Terms—Flyin...

The design, analysis, and control methodology of an energy efficient and high force to weight rat... more The design, analysis, and control methodology of an energy efficient and high force to weight ratio rare earth N42 NdFeB based permanent magnet linear oscillating motor has been described. For this axial flux machine the mover is consisting of Aluminium structure embedded with rare earth permanent magnets of high energy density. Microcontroller based drive is developed for frequency and thrust control of the machine. Finite element method using FEMM is employed for analysis of various performance parameters of machine. The same parameters are also compared with the measured ones, which yields a good agreement to the proposed design.

To guarantee a good productivity and a better quality of the industrial systems, it is necessary ... more To guarantee a good productivity and a better quality of the industrial systems, it is necessary to know the evolution of its various parameters but also its operation mode. The main goal of this work is to carry out a study to improve a flatness control in a reversing cold rolling mill, precisely the web winding system part. We designate by a winding process any system applying the cycles of unwinding, transport, treatment and winding to various flat products. This system knows several constraints such as the thermal effects caused by the frictions, and the mechanical effects provoked by metal elongation, that generates dysfunctions due to the influence of the process conditions. For this installations type, the various automatisms functions, often very advanced, are realized in modular systems with distributed architecture. Our main goal is to obtain a precise thickness, with the best possible regularity. With this intention, we are preceded to the modelling and the control of the nonlinear dynamic behaviour of a web winding process.