Parag .Upadhyay | Indian Institute of Technology Delhi (original) (raw)

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Papers by Parag .Upadhyay

Research paper thumbnail of Effect ofArmature Reaction and Skewing on thePerformance ofRadial-fluxPermanent MagnetBrushlessDC Motor

Inthis paper theeffect ofarmaturereaction and skewing on theperformance ofa 70W,24V,350-rpmsurfac... more Inthis paper theeffect ofarmaturereaction and skewing on theperformance ofa 70W,24V,350-rpmsurface mountedradial-flux permanentmagnetbrushless dc (PM BLDC)motorispresented. Thenetreduction inpeaktorque ofthemotorduetheeffect ofarmaturereaction isonly2.8%. Therateofreduction inairgapfluxdensity because ofthe armaturereaction is5.59mT/Afromno-load tofull-load. The 2DFinite element (FE)results areexploited fortheanalysis of skewing. Thepercentage torque ripple isreduced from24% to 13.63%and7.07%forthehalfandfullslotpitchskewing respectively.

Research paper thumbnail of Integrating Modular Hydrogen Fuel Cell Drives for Ship Propulsion: Prospectus and Challenges

TransNav: International Journal on Marine Navigation and Safety of Sea Transportation, 2012

This paper proposes a new drive system for ship propulsion. The drive power for propelling a ship... more This paper proposes a new drive system for ship propulsion. The drive power for propelling a ship varies from few MW in a small cruise ship to hundreds of MW for large cargo ships. A typical cruise ship has a 6 MW drive whereas a cargo ship has 80 MW drive. Combustion drives are not sustainable and environmentally friendly. The idea of an electric drive system using hydrogen fuel cell and necessary storage has been proposed. The hydrogen reformer develops hydrogen fuel cell using off-shore renewables like Wind, Wave and Solar power, but the power handling capability of this fuel cell system (100 kW) restricts the application to the propulsion drives of several MW. The detail drive scheme describes how multiple modular hydrogen fuel cell drives are integrated to develop variable power. The different options available for the propulsion system and factors affecting the choice are discussed in detail. Also, how such modular drives are helpful in controlling torque and power requirement...

Research paper thumbnail of Novel Concept for Flexible and Resilient Large Power Transformers

Research paper thumbnail of Core Loss Estimation in Electric Machines with Flux Controlled Core Loss Tester

IEEE Transactions on Industry Applications

The complexity of core loss estimation is a serious challenge in the design of high-efficiency el... more The complexity of core loss estimation is a serious challenge in the design of high-efficiency electric machines. Current estimation methods based on the Steinmetz equation and loss separation are not accurate enough, even at the rated conditions. This paper describes a loss estimation technique combining finite-element analysis (FEA) and actual core loss measurements. First, flux density waveforms in various parts of the electric machine are determined using FEA. Second, the same waveforms are generated in a wound toroidal core made of the same material as used in the machine. The loss is measured per unit mass, and then the total motor core loss is calculated by integrating the measured W/kg loss values for predefined sections of the motor. These estimation results are compared with those of the Bertotti method. The proposed procedure is shown to improve the accuracy of loss estimation.

Research paper thumbnail of Magnetic Thrust Bearings

Research paper thumbnail of 17. Integrating Modular Hydrogen Fuel Cell Drives for Ship Propulsion: Prospectus and Challenges

Research paper thumbnail of Simulation and analysis of high-speed modular flywheel energy storage systems using MATLAB/Simulink

Research paper thumbnail of CAD and FE analysis of radial-flux surface mounted permanent magnet brushless dc motor

In this paper, a computer-aided design (CAD) procedure for a radial-flux surface mounted permanen... more In this paper, a computer-aided design (CAD) procedure for a radial-flux surface mounted permanent magnet brushless dc (PM BLDC) motor is presented. The design variables such as airgap flux density, slot electric loading, winding factor, stacking factor, stator current density, slot space factor, magnet fraction, slot fraction, and flux density in the stator back iron, etc. are assumed for which the guidelines and justifications are discussed. The designs arrived at using the developed CAD program are giving required torque within an acceptable tolerance. Also, the efficiencies of the motors designed in each category of fractional, low and medium hp motors using the developed CAD program are sufficiently high in comparison with conventional motors.

Research paper thumbnail of FE Analysis and CAD of Sandwiched Axial-Flux Permanent Magnet Brushless dc Motor

ABSTRACT A generalized design procedure for a 70 W, 350 rpm axial-flux permanent magnet brushless... more ABSTRACT A generalized design procedure for a 70 W, 350 rpm axial-flux permanent magnet brushless DC (PM BLDC) motor having stator sandwiched between two permanent magnet rotors is presented. Based on the expressions for the torque and back emf, the output equation for an axial-flux PM BLDC motor, is derived. The optimized ratio of outer diameter to the inner diameter is used to derive the sizing equation. Using the sizing equations, a computer aided design (CAD) program which involves two self-corrective loops - one for the efficiency and the other for the airgap flux density - is developed.

Research paper thumbnail of Torque Ripple Minimization of Interior Permanent Magnet Brushless DC Motor Using Rotor Pole Shaping

ABSTRACT In this paper effort is made for the torque ripple minimization of a 70 W, 24 Volt, 350 ... more ABSTRACT In this paper effort is made for the torque ripple minimization of a 70 W, 24 Volt, 350 rpm, interior permanent magnet brushless DC (IPM BLDC) motor. The rotor pole shaping along with the pole shifting is analyzed. The results obtained from FE analyses have been discussed. The proper design and geometry of the motor reduces the cogging torque and the proper excitation reduces the mutual torque ripple. The torque ripple minimization using only the stator excitation makes the controller inefficient as well as costlier. Using the methods used in this paper, the torque ripple of the IPM BLDC motor is reduces and also the average torque is improved. In this method concept of magnet shifting is utilized for the torque improvement and rotor saliency is provided to reduce the cogging torque. Detailed analysis and explanation is given in this paper. The wide range of torque control by changing the switching intervals is an additional advantage of this design.

Research paper thumbnail of Design and FE analysis of surface mounted permanent magnet motor/generator for high-speed modular flywheel energy storage systems

Research paper thumbnail of Computer aided design of an axial-field permanent magnet brushless dc motor for an electric vehicle

Journal of Applied Physics, 2003

ABSTRACT

Research paper thumbnail of Comparison of performance of the axial-field and radial-field permanent magnet brushless direct current motors using computer aided design and finite element methods

In this article, performance of 70 W, 350 rpm, axial-field and radial-field permanent magnet brus... more In this article, performance of 70 W, 350 rpm, axial-field and radial-field permanent magnet brushless dc motors is compared using computer aided design (CAD) and finite element (FE) methods. The design variables like number of poles, slots per pole per phase, airgap length, airgap flux density, slot electric loading, stator flux density, and the permanent magnet material are changed one at a time and the performances are calculated using the developed CAD program. The CAD results are validated by carrying out two-dimensional and three-dimensional FE analyses. It is observed that the axial-field motor gives higher efficiency, whereas the radial-field motor has less weight.

Research paper thumbnail of Involvement of Armature Reaction Property in the Computer Aided Design of Radial-Flux Permanent Magnet Brushless DC Motor

The effect of armature reaction on the performance of a 70 W, 24 volt, 6-pole, 350-rpm surface mo... more The effect of armature reaction on the performance of a 70 W, 24 volt, 6-pole, 350-rpm surface mounted radial-flux permanent magnet brushless dc (PM BLDC) motor is presented. The two distinct effects viz. demagnetizing and cross magnetizing effects of the armature reaction on the performance of radial-flux PM BLDC motor are discussed.

Research paper thumbnail of Effect ofArmature Reaction and Skewing on thePerformance ofRadial-fluxPermanent MagnetBrushlessDC Motor

Inthis paper theeffect ofarmaturereaction and skewing on theperformance ofa 70W,24V,350-rpmsurfac... more Inthis paper theeffect ofarmaturereaction and skewing on theperformance ofa 70W,24V,350-rpmsurface mountedradial-flux permanentmagnetbrushless dc (PM BLDC)motorispresented. Thenetreduction inpeaktorque ofthemotorduetheeffect ofarmaturereaction isonly2.8%. Therateofreduction inairgapfluxdensity because ofthe armaturereaction is5.59mT/Afromno-load tofull-load. The 2DFinite element (FE)results areexploited fortheanalysis of skewing. Thepercentage torque ripple isreduced from24% to 13.63%and7.07%forthehalfandfullslotpitchskewing respectively.

Research paper thumbnail of Integrating Modular Hydrogen Fuel Cell Drives for Ship Propulsion: Prospectus and Challenges

TransNav: International Journal on Marine Navigation and Safety of Sea Transportation, 2012

This paper proposes a new drive system for ship propulsion. The drive power for propelling a ship... more This paper proposes a new drive system for ship propulsion. The drive power for propelling a ship varies from few MW in a small cruise ship to hundreds of MW for large cargo ships. A typical cruise ship has a 6 MW drive whereas a cargo ship has 80 MW drive. Combustion drives are not sustainable and environmentally friendly. The idea of an electric drive system using hydrogen fuel cell and necessary storage has been proposed. The hydrogen reformer develops hydrogen fuel cell using off-shore renewables like Wind, Wave and Solar power, but the power handling capability of this fuel cell system (100 kW) restricts the application to the propulsion drives of several MW. The detail drive scheme describes how multiple modular hydrogen fuel cell drives are integrated to develop variable power. The different options available for the propulsion system and factors affecting the choice are discussed in detail. Also, how such modular drives are helpful in controlling torque and power requirement...

Research paper thumbnail of Novel Concept for Flexible and Resilient Large Power Transformers

Research paper thumbnail of Core Loss Estimation in Electric Machines with Flux Controlled Core Loss Tester

IEEE Transactions on Industry Applications

The complexity of core loss estimation is a serious challenge in the design of high-efficiency el... more The complexity of core loss estimation is a serious challenge in the design of high-efficiency electric machines. Current estimation methods based on the Steinmetz equation and loss separation are not accurate enough, even at the rated conditions. This paper describes a loss estimation technique combining finite-element analysis (FEA) and actual core loss measurements. First, flux density waveforms in various parts of the electric machine are determined using FEA. Second, the same waveforms are generated in a wound toroidal core made of the same material as used in the machine. The loss is measured per unit mass, and then the total motor core loss is calculated by integrating the measured W/kg loss values for predefined sections of the motor. These estimation results are compared with those of the Bertotti method. The proposed procedure is shown to improve the accuracy of loss estimation.

Research paper thumbnail of Magnetic Thrust Bearings

Research paper thumbnail of 17. Integrating Modular Hydrogen Fuel Cell Drives for Ship Propulsion: Prospectus and Challenges

Research paper thumbnail of Simulation and analysis of high-speed modular flywheel energy storage systems using MATLAB/Simulink

Research paper thumbnail of CAD and FE analysis of radial-flux surface mounted permanent magnet brushless dc motor

In this paper, a computer-aided design (CAD) procedure for a radial-flux surface mounted permanen... more In this paper, a computer-aided design (CAD) procedure for a radial-flux surface mounted permanent magnet brushless dc (PM BLDC) motor is presented. The design variables such as airgap flux density, slot electric loading, winding factor, stacking factor, stator current density, slot space factor, magnet fraction, slot fraction, and flux density in the stator back iron, etc. are assumed for which the guidelines and justifications are discussed. The designs arrived at using the developed CAD program are giving required torque within an acceptable tolerance. Also, the efficiencies of the motors designed in each category of fractional, low and medium hp motors using the developed CAD program are sufficiently high in comparison with conventional motors.

Research paper thumbnail of FE Analysis and CAD of Sandwiched Axial-Flux Permanent Magnet Brushless dc Motor

ABSTRACT A generalized design procedure for a 70 W, 350 rpm axial-flux permanent magnet brushless... more ABSTRACT A generalized design procedure for a 70 W, 350 rpm axial-flux permanent magnet brushless DC (PM BLDC) motor having stator sandwiched between two permanent magnet rotors is presented. Based on the expressions for the torque and back emf, the output equation for an axial-flux PM BLDC motor, is derived. The optimized ratio of outer diameter to the inner diameter is used to derive the sizing equation. Using the sizing equations, a computer aided design (CAD) program which involves two self-corrective loops - one for the efficiency and the other for the airgap flux density - is developed.

Research paper thumbnail of Torque Ripple Minimization of Interior Permanent Magnet Brushless DC Motor Using Rotor Pole Shaping

ABSTRACT In this paper effort is made for the torque ripple minimization of a 70 W, 24 Volt, 350 ... more ABSTRACT In this paper effort is made for the torque ripple minimization of a 70 W, 24 Volt, 350 rpm, interior permanent magnet brushless DC (IPM BLDC) motor. The rotor pole shaping along with the pole shifting is analyzed. The results obtained from FE analyses have been discussed. The proper design and geometry of the motor reduces the cogging torque and the proper excitation reduces the mutual torque ripple. The torque ripple minimization using only the stator excitation makes the controller inefficient as well as costlier. Using the methods used in this paper, the torque ripple of the IPM BLDC motor is reduces and also the average torque is improved. In this method concept of magnet shifting is utilized for the torque improvement and rotor saliency is provided to reduce the cogging torque. Detailed analysis and explanation is given in this paper. The wide range of torque control by changing the switching intervals is an additional advantage of this design.

Research paper thumbnail of Design and FE analysis of surface mounted permanent magnet motor/generator for high-speed modular flywheel energy storage systems

Research paper thumbnail of Computer aided design of an axial-field permanent magnet brushless dc motor for an electric vehicle

Journal of Applied Physics, 2003

ABSTRACT

Research paper thumbnail of Comparison of performance of the axial-field and radial-field permanent magnet brushless direct current motors using computer aided design and finite element methods

In this article, performance of 70 W, 350 rpm, axial-field and radial-field permanent magnet brus... more In this article, performance of 70 W, 350 rpm, axial-field and radial-field permanent magnet brushless dc motors is compared using computer aided design (CAD) and finite element (FE) methods. The design variables like number of poles, slots per pole per phase, airgap length, airgap flux density, slot electric loading, stator flux density, and the permanent magnet material are changed one at a time and the performances are calculated using the developed CAD program. The CAD results are validated by carrying out two-dimensional and three-dimensional FE analyses. It is observed that the axial-field motor gives higher efficiency, whereas the radial-field motor has less weight.

Research paper thumbnail of Involvement of Armature Reaction Property in the Computer Aided Design of Radial-Flux Permanent Magnet Brushless DC Motor

The effect of armature reaction on the performance of a 70 W, 24 volt, 6-pole, 350-rpm surface mo... more The effect of armature reaction on the performance of a 70 W, 24 volt, 6-pole, 350-rpm surface mounted radial-flux permanent magnet brushless dc (PM BLDC) motor is presented. The two distinct effects viz. demagnetizing and cross magnetizing effects of the armature reaction on the performance of radial-flux PM BLDC motor are discussed.