Ankita Dwivedi

Fabrication and comparison of linear power supplies for low-moderate voltage applications

For low power (up to 25-30 W) regulated DC power supply, it is generally advantageous to go for the LPS (Linear Power Supply) instead of the SMPS (switch mode power supply). Commercially available DC voltage regulators, either fixed or variable fail to sustain high load current and high input voltage. This paper presents some possible schemes to fulfil these requirements and a modified LPS hardware circuit with associated resultant tested in laboratory. Final circuit contains a novel way for isolation and error amplification through a single IC.

Analysis and performance evaluation of axial flux permanent magnet motors

For special types of electric machines, it is essential and of utmost interest to develop a mathematical model, characterize a machine for performance evaluation, and test the machine for study and applications. A 2-D analytical method for the performance evaluation of axial flux permanent magnet (AFPM) machine has been presented in this paper. The method computes the electromagnetic torque, magnetic field distribution, cogging torque, and back-electromotive force of the machine using quasi-3-D modeling. Fourier Transform is used for the solution of Maxwells equations in different regions of the AFPM machine. A surface mounted AFPM motor is designed and developed and tested. Experimental results are demonstrated and compared with the results computed from the analytical model to validate the effectiveness and accuracy of the proposed method.

Experiences with Axial-Flux induction motor

The present paper describes the design fabrication of a low cost Axial Flux Induction Motor having radial slots. Toroidal double sided stator ferromagnetic core has two distinct separate three phase slot-by-slot windings, each of active surface of stator is facing toroidal rotor ferromagnetic core having squirrel cage of either copper or brass bars. The rotor bars are short circuited using inner and outer copper rings so as to form a cage winding. Stator slots and rotor slots are created using drilling operations. The stator carries three phase distributed windings whereas rotor haves the brass/ copper bars embedded on the rotor slots and short circuited by inner and outer copper rings. The equivalent circuit parameters i.e., resistance and leakage reactance are determined using design details as well as obtained from tests. The torque speed characteristics of AFIM thus computed to show good validations.

Experiences with axial flux sheet rotor induction motor

The paper discusses experience with a 2-phase axial flux sheet rotor induction motor. The motor is a single stator solid sheet rotor induction motor. The sheet is made of Aluminium disc of 3mm thickness. The application of axial flux sheet rotor Induction motor can be extended to electric vehicles or hybrid electric vehicles due to compatible shape and easy construction. The absence of windings and bars reduces overall losses, hence increasing the efficiency of the proposed motor. Although the eddy currents induced in the sheet rotor needs to be studied.

Study of 8/12 flux reversal machine as an alternator

Flux Reversal Machine (FRM), an emerging doubly salient PM motor is well known for retaining advantage of switched reluctance and PM machine. The paper presents study of a Flux Reversal PM machine as an alternator. Analysis, construction, and experimental results for a 8/12 prototype FRM as a single-phase flux reversal alternator are presented.

Performance comparison of different topologies of PMBLAC motor using FEM

The paper compares performance parameters such as flux density distribution, average torque, etc. of an 8-slot 6-pole Permanent Magnet Brushless (PMBL) motor with surface mounted (SMPM), surface inset (SIPM), and interior PM (IPM) rotor topologies using Finite Element Analysis (FEM). Successful operation of Permanent Magnet (PM) motors with cogging/ripple free torque depends on sinusoidal flux density. Presence of cogging torque due to slotted stator in SMPM, SIPM and IPM motors is studied. The study will help in selection of different topologies of PMBL motors owing to their flux distribution, suitability at high speeds and torque production.