Dheeraj Bobba

Dheeraj Bobba
Powersys Solutions

Doctor of Philosophy

About

45
Publications
22,272
Reads
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428
Citations
Citations since 2017
25 Research Items
366 Citations
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080

Publications

Publications (45)
Conference Paper
Full-text available
Wound-field flux-switching (WFFS) machines have both field and armature windings in the stator, eliminating the need for permanent magnets in the rotor. This leads to a simple and robust electric machine design with variable flux operation capability. However, it is important to note that these two sets of windings (i.e., field and armature) need t...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2021-3306.vid The electrification of commercial aircraft propulsion requires the development of megawatt-class electrical machines possessing high power density, high efficiency, and effective cooling. These demands are explored in this presentation of a megawatt-class surface permanent magnet (SPM...
Article
Full-text available
Gallium nitride (GaN) high electron mobility transistor (HEMT) has a lateral device structure with wafer-level packaging, which is advantageous in minimizing parasitic parameters and overall device size. This type of packaging also has better thermal performance than the conventional packaging due to low junction-to-bottom thermal resistances. It i...
Article
Full-text available
This paper presents a novel perspective to understand different winding configurations of flux-switching permanent magnet (FSPM) machines. A simple analytical method is used for the calculation of total offset angle of flux linkages by taking into account an offset angle of stator slot and rotor poles. The closed-form solution is presented to find...
Article
The axial overhang of the permanent magnet (PM) has widely been used to enhance the thrust per loss, particularly in air-core structure where the radial flux density is low. This communication investigates PM overhang effects in coreless-type PM linear machines. To analyze the structure where the magnet length exceeds the active length of the mover...
Article
The objective of this paper is to investigate the design and optimization of a novel dual-rotor hybrid permanent magnet (DR-HPM) machine for traction application. The proposed dual-rotor hybrid synchronous PM machine synthesizes the synchronous reluctance (SyR) and surface permanent magnet (SPM) rotors into a single machine with the common shaft by...
Article
Full-text available
Forced induction uses otherwise wasted exhaust gases to improve the volumetric efficiency of an engine allowing for higher thermodynamic efficiency. As the fuel economy and greenhouse gas emission standards are projected to be much more stringent globally, the use of a forced induction engine in passenger cars and light duty trucks has become a new...
Article
The purpose of this research is to propose a novel concept of a high-speed electric machine system with integrated airfoil-shaped rotor designed to perform axial-flow compression for vehicle applications. The proposed high-speed machine is both a motor for electromagnetic energy conversion and an axial-flow compressor for thermodynamic energy conve...
Conference Paper
Flux switching permanent magnet machines provide many advantages. Due to their superior behavior associated with sinusoidal Back-EMF and low torque ripple, topologies featuring 12 stator teeth and 10 rotor poles (12/10) are favored. However, this follows that for a given mechanical rotor speed, the required electric fundamental frequency is ten tim...
Conference Paper
The goal of this paper is to propose a novel concept of permanent magnet machine with integrated airfoil-shaped rotor that can perform compression action. Electrically driven conventional compressor systems need electric machines as prime movers to provide mechanical energy to rotate the compressor. The proposed novel integrated permanent magnet ma...
Article
The purpose of this paper is to investigate a novel flux-switching permanent magnet (FSPM) machine that is amenable for high-speed operation. The low-pole topology of high-speed machine is favorable to minimize fundamental frequency requirement. The lowest possible three-phase topology of the FSPM machine, with six stator slots and four rotor poles...
Conference Paper
This paper presents an analytical method to realize even order harmonic elimination in flux-switching permanent magnet machines. The proposed method enables the calculation of total offset angle of flux linkages, taking into account an offset angle of stator slot and rotor poles. The 6-slot, 12-slot, and dual structure flux-switching permanent magn...
Conference Paper
Full-text available
Forced induction technology (turbocharging and supercharging) can enhance the performance of an internal combustion engine by compressing inlet air charge, allowing full engine power to be produced efficiently. As the fuel economy and greenhouse gas emission standards are projected to be much more stringent globally, the use of a forced induction e...
Conference Paper
This paper presents a novel perspective to understand different winding configurations of even and odd number of rotor pole flux-switching permanent magnet machines. A simple analytical method is used for the calculation of total offset angle of flux linkages by taking into account an offset angle of stator slot and rotor poles. The 12-slot/10-pole...
Conference Paper
High-speed machines are gaining interest, especially in traction applications because of their ability to produce high power density with a reduced size. Flux-switching permanent magnet (FSPM) machines are ideal for such applications since they have a simple rotor structure that can operate at very high speeds and utilize PM in the stator to achiev...
Conference Paper
Full-text available
The purpose of this paper is to characterize the performance of a novel dual-stator six-slot four-pole (6/4) flux-switching permanent magnet (FSPM) machine. The proposed dual-stator 6/4 FSPM machine topology eliminates even-order harmonics in the flux linkage and back-electromotive force, which exist in the conventional single-stator single-rotor t...
Article
Full-text available
Flux switching permanent magnet (FSPM) machines are innovative brushless machines that have magnets built into the stator instead of the rotor. Numerous studies were performed comparing the operational characteristics of FSPM machines with that of traditional PM machines as well as comparing the various design configurations of FSPM machines within...
Conference Paper
Full-text available
The purpose of this paper is to introduce a novel dual-stator six stator slots four rotor poles flux switching permanent magnet machine that is viable for operation. The conventional six slots four poles topology suffers from asymmetrical flux linkage and severely unbalanced back-EMF, which makes it unfeasible. The proposed dual-stator structure ut...
Conference Paper
Full-text available
The high-speed machine design is becoming important due to advantages such as high-power density and small size. Flux-switching permanent magnet (FSPM) machines have a simple rotor design without any windings or PMs, which makes them apt for high-speed operation. A low-pole topology of the FSPM machine is desirable to keep the operational frequency...
Article
Full-text available
A modeling approach is presented that enables the 3-D field external to a complicated magnetic source to be reproduced using an equivalent fictitious magnetic charge sheet. It is shown that the value of the equivalent magnetic charge sheet can be determined from the normal component of the magnetic source. The field distribution due to a cylindrica...
Conference Paper
Full-text available
When a magnetic rotor is simultaneously rotated and translationally moved above an aluminum guideway a traveling time-varying magnetic field is created in the air-gap. This field induces eddy currents in the guideway that can simultaneously create suspension and propulsion or braking forces. The transient fields and the forces created by this movin...
Article
Full-text available
An efficient three-dimensional transient finite element method for calculating the lift, thrust and lateral forces created when a magnetic rotor is both translationally moved and rotated above an aluminum sheet guideway is presented. The rotor field is calculated from an equivalent fictitious magnetic charge sheet formula. The rotor field's effect...

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Projects

Projects (4)
Project
The goal of this research is to investigate the proposed innovative family of electric machines that integrates the axial-flow compression into the electric machine by shaping the salient rotor poles as compressor airfoils. The proposed integrated machine has benefits of a more compact overall system, higher reliability due to the elimination of potential gearbox, and high efficiency. The research is multi-physics in nature with the analysis in the domains of electromagnetics, thermodynamics, and structural dynamics. This project is funded by NSF CAREER Award.