Mehrdad Ehsani - Academia.edu (original) (raw)

Papers by Mehrdad Ehsani

Research paper thumbnail of Evaluation of the GTO for 270 MVA Interrupter Applications

IEEE Transactions on Nuclear Science, 1985

... 'I'The CurnrriuttatiouiTi(ciri i; siTilarI to the Circuit chosen to coun-te... more ... 'I'The CurnrriuttatiouiTi(ciri i; siTilarI to the Circuit chosen to coun-terpulse the xacu urii inIterruplter except that the sat urable reactor is remiooxed3 aud ant ii tuc-tor. ... This SCR has a voltage ratinig of 430(0 Va current ratillg of 2120 AjL\s. a oIne cycle surge ca-pacity of 25 kA. ...

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Research paper thumbnail of Fundamentals of Regenerative Breaking

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Research paper thumbnail of Permanent-Magnet Synchronous

A new approach to the position sensor elimination of an interior permanent-magnet (IPM) synchrono... more A new approach to the position sensor elimination of an interior permanent-magnet (IPM) synchronous motor drive is proposed in this paper. The phase inductance of an IPM synchronous motor varies appreciably as a function of the rotor position. This feature is utilized to get an estimate of the rotor position. Analytical equations are developed in this paper for the calculation of the phase inductance of an IPM motor driven by a current-controlled PWM converter with a hysteresis con- troller. The calculated phase inductance is then used to estimate the position of the rotor using a set of stored data relating the phase inductance and the rotor position. In order to obtain an unambiguous relation between the phase inductance and the rotor position, the phase inductance of phases a, b, and c is calculated during different segments of each electrical cycle. A direct approach to inductance calculation, which is computa- tionally less intensive and gives uniformly good results, is also pr...

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Research paper thumbnail of High step-up Z-source DC-DC converter with flyback and voltage multiplier

2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017

Recently, because of the pollution problems of the fossil fuels, demand of renewable energy sourc... more Recently, because of the pollution problems of the fossil fuels, demand of renewable energy sources is increased. Solar panels and fuel-cells generate low voltage, therefore high voltage gain dc-dc converters are needed to boost their low output voltage to meet the inverters required voltage. Z-source converter has several advantages such as high voltage gain, isolated energy source from the load side, clamped switch voltage and positive output voltage polarity, therefore it is a suitable choice for high step-up applications. This paper presents a non-isolated high step-up dc-dc converter which is the derivation of z-source converter and has a higher voltage gain in comparison to the conventional converters. This advantage makes this converter a suitable choice for photovoltaic applications. Moreover, high boost voltage is obtained with low duty cycle and the energy of leakage inductances is absorbed so the efficiency is increased. A 100 W laboratory prototype to convert 24–300 V is implemented to verify the theoretical and simulation results.

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Research paper thumbnail of Design and Control Methodology of Series–Parallel (Torque and Speed Coupling) Hybrid Drive Train

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Research paper thumbnail of User Guide for Multiobjective Optimization Toolbox

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Research paper thumbnail of Sustainable pavement maintenance and rehabilitation planning using differential evolutionary programming and coyote optimisation algorithm

International Journal of Pavement Engineering, 2021

CO2 emission reduction in large-scale pavement network maintenance planning has been an immense c... more CO2 emission reduction in large-scale pavement network maintenance planning has been an immense concern. The conventional single-objective optimisation modelsoverlook environmental issues such as C...

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Research paper thumbnail of An Investigation of Natural Gas as a Substitute for Diesel in Heavy Duty Trucks and Associated Considerations

arXiv: Physics and Society, 2015

In this paper, applicability of natural gas fuel for transportation as compared to diesel is inve... more In this paper, applicability of natural gas fuel for transportation as compared to diesel is investigated. This study investigates a promising technology for the heavy duty truck sector of transportation as a target for conversion from diesel to natural gas. The supply of natural gas is limited so we also verify the available domestic supply quantities both before and after a fleet conversion. This paper concludes with an economic discussion regarding Javon's paradox and the fungibility of natural gas as compared to that of oil. In order to determine if natural gas can replace diesel for the country's heavy duty truck transportation needs, the energy equivalent and efficiency of natural gas alternatives should be compared to diesel. There are two alternatives for using natural gas as a replacement for diesel; compressed natural gas and liquefied natural gas.

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Research paper thumbnail of New Two-Quadrant Converter For Complete Decoupled Control Of The Dc Series Motor

IECON '87: Motor Control and Power Electronics, 1987

New chopper circuits for decoupled operation of the dc series motor are presented. These new chop... more New chopper circuits for decoupled operation of the dc series motor are presented. These new choppers are capable of controlling field current completely separately, while offering capability of bidirectional armature energy flow. To develop the chopper circuit, with minimum number of switching elements, the complete family of possible conduction circuits are systematically investigated. Then one or two quadrant chopper circuits which offer the desired operations are synthesized from the resulting conduction circuits. Finally, the developed chopper circuits are completely analyzed. The details of operation of the chopper circuits are also fully described.

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Research paper thumbnail of Overview of reduced parts converter topologies for AC motor drives

2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230)

In this paper, various reduced parts converter topologies and control strategies for power factor... more In this paper, various reduced parts converter topologies and control strategies for power factor correction and motor control are reviewed and systematic design methodology is developed. From this investigation, the converter topologies could be mainly categorized into cascade type and unified type. The detailed operational principles are examined and the performance comparison Is derived to illustrate merits and limitations of

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Research paper thumbnail of A versatile DC-DC and DC-AC converter with zero current soft switching

Proceedings of IECON '93 - 19th Annual Conference of IEEE Industrial Electronics

A versatile DC-DC and DC-AC capacitively coupled power converter which is capable of zero current... more A versatile DC-DC and DC-AC capacitively coupled power converter which is capable of zero current soft switching is presented. This converter can supply both DC and AC loads with a higher system efficiency due to its zero current switching operation. The DC output is regulated by pulse width modulation (PWM) while the AC waveform is controlled by amplitude modulation (AM) and discrete pulse modulation (DPM). This versatile converter is suitable for high power high efficiency applications, such as solar energy conversion and uninterruptible power systems (UPS).<<ETX>>

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Research paper thumbnail of Characterization of electric motor drives for traction applications

IECON'03. 29th Annual Conference of the IEEE Industrial Electronics Society (IEEE Cat. No.03CH37468)

Page 1. Characterization of Electric Motor Drives for Traction Applications Mehrdad. Ehsani, Yimi... more Page 1. Characterization of Electric Motor Drives for Traction Applications Mehrdad. Ehsani, Yimin Gao, and Stbastien Gay Advanced Vehicle systems Research Program Department of electrical engineering Texas ABIM University ...

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Research paper thumbnail of Investigation of battery technologies for the army's hybrid vehicle application

Proceedings IEEE 56th Vehicular Technology Conference

A theoretical electrochemical cell is designed for the highest practical energy density. The mate... more A theoretical electrochemical cell is designed for the highest practical energy density. The materials are selected on the basis of bonding energies of the elements in the periodic table. It is shown that the physical limit to energy density of batteries is about 10-13 times larger than in the present lead-acid batteries, and an optimistic practical limit is approximately 450 Wh/kg. Based on the basic energy and power requirements of military vehicles and supposing that 25% is the maximum acceptable value of battery weight ratio to vehicle total weight, it is found that the proposed high energy density battery can support the vehicle highway driving at speeds of 70 mph for over 250 miles, and 15 miles at hill climbing at speeds of 6 mph. It is also found that with the best currently available batteries, the highway driving range is only about 105 miles, and hill climbing for about 6.4 miles. The study also shows that power capacities of batteries at present can meet the power requirement of the vehicle, even in hard acceleration.

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Research paper thumbnail of Maximum power throughput in the multiphase BLDC generator

30th Annual Conference of IEEE Industrial Electronics Society, 2004. IECON 2004

... USA, e-mail: h1333@corneILedu 2.3Taehyung Kim and Mehrdad Ehsani, Department of Electrical En... more ... USA, e-mail: h1333@corneILedu 2.3Taehyung Kim and Mehrdad Ehsani, Department of Electrical Engineering, Texas A&M University, USA, e-mail: thkim@ee.tamu.edu, ehsani@ee.tamu.edu Abstract This paper presents ...

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Research paper thumbnail of Commutation of SR motors

[Proceedings] APEC '91: Sixth Annual Applied Power Electronics Conference and Exhibition

The authors present commutation schemes for the most common types of switched reluctance motors (... more The authors present commutation schemes for the most common types of switched reluctance motors (SRMs). These schemes permit the realization of four-quadrant multimode SR motor drive operation with a simple logic control and with position feedback from low-resolution position sensors. A case study of a four-quadrant SR drive with multimode operation for a three-phase motor with six stator and four rotor poles is used to illustrate the method used in deriving the commutation schemes.<<ETX>>

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Research paper thumbnail of Modern Electric, Hybrid Electric, and Fuel Cell Vehicles

Power Electronics and Applications Series, 2004

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Research paper thumbnail of Reactive Power Coordination of Shipboard Power Systems in Presence of Pulsed Loads

IEEE Transactions on Power Systems, 2013

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Research paper thumbnail of Generalized Gyrator Theory

IEEE Transactions on Power Electronics, 2010

... Laboratory, Department of Electrical Engineering, Texas A&amp;amp;M University, College S... more ... Laboratory, Department of Electrical Engineering, Texas A&amp;amp;M University, College Station, TX 77843 USA, on leave from the Office for Re-search, Technological University of Panama, Panama City, Panama (e-mail: ronald.barazarte@utp.ac.pa; guadalupe.gonzalez@utp.ac.pa). ...

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Research paper thumbnail of Parametric design of the traction motor and energy storage for series hybrid off-road and military vehicles

IEEE Transactions on Power Electronics, 2006

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Research paper thumbnail of A torque and speed coupling hybrid drivetrain-architecture, control, and simulation

IEEE Transactions on Power Electronics, 2006

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Research paper thumbnail of Evaluation of the GTO for 270 MVA Interrupter Applications

IEEE Transactions on Nuclear Science, 1985

... &#x27;I&#x27;The CurnrriuttatiouiTi(ciri i; siTilarI to the Circuit chosen to coun-te... more ... &#x27;I&#x27;The CurnrriuttatiouiTi(ciri i; siTilarI to the Circuit chosen to coun-terpulse the xacu urii inIterruplter except that the sat urable reactor is remiooxed3 aud ant ii tuc-tor. ... This SCR has a voltage ratinig of 430(0 Va current ratillg of 2120 AjL\s. a oIne cycle surge ca-pacity of 25 kA. ...

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Research paper thumbnail of Fundamentals of Regenerative Breaking

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Permanent-Magnet Synchronous

A new approach to the position sensor elimination of an interior permanent-magnet (IPM) synchrono... more A new approach to the position sensor elimination of an interior permanent-magnet (IPM) synchronous motor drive is proposed in this paper. The phase inductance of an IPM synchronous motor varies appreciably as a function of the rotor position. This feature is utilized to get an estimate of the rotor position. Analytical equations are developed in this paper for the calculation of the phase inductance of an IPM motor driven by a current-controlled PWM converter with a hysteresis con- troller. The calculated phase inductance is then used to estimate the position of the rotor using a set of stored data relating the phase inductance and the rotor position. In order to obtain an unambiguous relation between the phase inductance and the rotor position, the phase inductance of phases a, b, and c is calculated during different segments of each electrical cycle. A direct approach to inductance calculation, which is computa- tionally less intensive and gives uniformly good results, is also pr...

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Research paper thumbnail of High step-up Z-source DC-DC converter with flyback and voltage multiplier

2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017

Recently, because of the pollution problems of the fossil fuels, demand of renewable energy sourc... more Recently, because of the pollution problems of the fossil fuels, demand of renewable energy sources is increased. Solar panels and fuel-cells generate low voltage, therefore high voltage gain dc-dc converters are needed to boost their low output voltage to meet the inverters required voltage. Z-source converter has several advantages such as high voltage gain, isolated energy source from the load side, clamped switch voltage and positive output voltage polarity, therefore it is a suitable choice for high step-up applications. This paper presents a non-isolated high step-up dc-dc converter which is the derivation of z-source converter and has a higher voltage gain in comparison to the conventional converters. This advantage makes this converter a suitable choice for photovoltaic applications. Moreover, high boost voltage is obtained with low duty cycle and the energy of leakage inductances is absorbed so the efficiency is increased. A 100 W laboratory prototype to convert 24–300 V is implemented to verify the theoretical and simulation results.

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Research paper thumbnail of Design and Control Methodology of Series–Parallel (Torque and Speed Coupling) Hybrid Drive Train

Bookmarks Related papers MentionsView impact

Research paper thumbnail of User Guide for Multiobjective Optimization Toolbox

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Sustainable pavement maintenance and rehabilitation planning using differential evolutionary programming and coyote optimisation algorithm

International Journal of Pavement Engineering, 2021

CO2 emission reduction in large-scale pavement network maintenance planning has been an immense c... more CO2 emission reduction in large-scale pavement network maintenance planning has been an immense concern. The conventional single-objective optimisation modelsoverlook environmental issues such as C...

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Research paper thumbnail of An Investigation of Natural Gas as a Substitute for Diesel in Heavy Duty Trucks and Associated Considerations

arXiv: Physics and Society, 2015

In this paper, applicability of natural gas fuel for transportation as compared to diesel is inve... more In this paper, applicability of natural gas fuel for transportation as compared to diesel is investigated. This study investigates a promising technology for the heavy duty truck sector of transportation as a target for conversion from diesel to natural gas. The supply of natural gas is limited so we also verify the available domestic supply quantities both before and after a fleet conversion. This paper concludes with an economic discussion regarding Javon's paradox and the fungibility of natural gas as compared to that of oil. In order to determine if natural gas can replace diesel for the country's heavy duty truck transportation needs, the energy equivalent and efficiency of natural gas alternatives should be compared to diesel. There are two alternatives for using natural gas as a replacement for diesel; compressed natural gas and liquefied natural gas.

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Research paper thumbnail of New Two-Quadrant Converter For Complete Decoupled Control Of The Dc Series Motor

IECON '87: Motor Control and Power Electronics, 1987

New chopper circuits for decoupled operation of the dc series motor are presented. These new chop... more New chopper circuits for decoupled operation of the dc series motor are presented. These new choppers are capable of controlling field current completely separately, while offering capability of bidirectional armature energy flow. To develop the chopper circuit, with minimum number of switching elements, the complete family of possible conduction circuits are systematically investigated. Then one or two quadrant chopper circuits which offer the desired operations are synthesized from the resulting conduction circuits. Finally, the developed chopper circuits are completely analyzed. The details of operation of the chopper circuits are also fully described.

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Research paper thumbnail of Overview of reduced parts converter topologies for AC motor drives

2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230)

In this paper, various reduced parts converter topologies and control strategies for power factor... more In this paper, various reduced parts converter topologies and control strategies for power factor correction and motor control are reviewed and systematic design methodology is developed. From this investigation, the converter topologies could be mainly categorized into cascade type and unified type. The detailed operational principles are examined and the performance comparison Is derived to illustrate merits and limitations of

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A versatile DC-DC and DC-AC converter with zero current soft switching

Proceedings of IECON '93 - 19th Annual Conference of IEEE Industrial Electronics

A versatile DC-DC and DC-AC capacitively coupled power converter which is capable of zero current... more A versatile DC-DC and DC-AC capacitively coupled power converter which is capable of zero current soft switching is presented. This converter can supply both DC and AC loads with a higher system efficiency due to its zero current switching operation. The DC output is regulated by pulse width modulation (PWM) while the AC waveform is controlled by amplitude modulation (AM) and discrete pulse modulation (DPM). This versatile converter is suitable for high power high efficiency applications, such as solar energy conversion and uninterruptible power systems (UPS).<<ETX>>

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Research paper thumbnail of Characterization of electric motor drives for traction applications

IECON'03. 29th Annual Conference of the IEEE Industrial Electronics Society (IEEE Cat. No.03CH37468)

Page 1. Characterization of Electric Motor Drives for Traction Applications Mehrdad. Ehsani, Yimi... more Page 1. Characterization of Electric Motor Drives for Traction Applications Mehrdad. Ehsani, Yimin Gao, and Stbastien Gay Advanced Vehicle systems Research Program Department of electrical engineering Texas ABIM University ...

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Research paper thumbnail of Investigation of battery technologies for the army's hybrid vehicle application

Proceedings IEEE 56th Vehicular Technology Conference

A theoretical electrochemical cell is designed for the highest practical energy density. The mate... more A theoretical electrochemical cell is designed for the highest practical energy density. The materials are selected on the basis of bonding energies of the elements in the periodic table. It is shown that the physical limit to energy density of batteries is about 10-13 times larger than in the present lead-acid batteries, and an optimistic practical limit is approximately 450 Wh/kg. Based on the basic energy and power requirements of military vehicles and supposing that 25% is the maximum acceptable value of battery weight ratio to vehicle total weight, it is found that the proposed high energy density battery can support the vehicle highway driving at speeds of 70 mph for over 250 miles, and 15 miles at hill climbing at speeds of 6 mph. It is also found that with the best currently available batteries, the highway driving range is only about 105 miles, and hill climbing for about 6.4 miles. The study also shows that power capacities of batteries at present can meet the power requirement of the vehicle, even in hard acceleration.

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Research paper thumbnail of Maximum power throughput in the multiphase BLDC generator

30th Annual Conference of IEEE Industrial Electronics Society, 2004. IECON 2004

... USA, e-mail: h1333@corneILedu 2.3Taehyung Kim and Mehrdad Ehsani, Department of Electrical En... more ... USA, e-mail: h1333@corneILedu 2.3Taehyung Kim and Mehrdad Ehsani, Department of Electrical Engineering, Texas A&M University, USA, e-mail: thkim@ee.tamu.edu, ehsani@ee.tamu.edu Abstract This paper presents ...

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Research paper thumbnail of Commutation of SR motors

[Proceedings] APEC '91: Sixth Annual Applied Power Electronics Conference and Exhibition

The authors present commutation schemes for the most common types of switched reluctance motors (... more The authors present commutation schemes for the most common types of switched reluctance motors (SRMs). These schemes permit the realization of four-quadrant multimode SR motor drive operation with a simple logic control and with position feedback from low-resolution position sensors. A case study of a four-quadrant SR drive with multimode operation for a three-phase motor with six stator and four rotor poles is used to illustrate the method used in deriving the commutation schemes.<<ETX>>

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Research paper thumbnail of Modern Electric, Hybrid Electric, and Fuel Cell Vehicles

Power Electronics and Applications Series, 2004

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Reactive Power Coordination of Shipboard Power Systems in Presence of Pulsed Loads

IEEE Transactions on Power Systems, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Generalized Gyrator Theory

IEEE Transactions on Power Electronics, 2010

... Laboratory, Department of Electrical Engineering, Texas A&amp;amp;M University, College S... more ... Laboratory, Department of Electrical Engineering, Texas A&amp;amp;M University, College Station, TX 77843 USA, on leave from the Office for Re-search, Technological University of Panama, Panama City, Panama (e-mail: ronald.barazarte@utp.ac.pa; guadalupe.gonzalez@utp.ac.pa). ...

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Research paper thumbnail of Parametric design of the traction motor and energy storage for series hybrid off-road and military vehicles

IEEE Transactions on Power Electronics, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A torque and speed coupling hybrid drivetrain-architecture, control, and simulation

IEEE Transactions on Power Electronics, 2006

Bookmarks Related papers MentionsView impact