Faculty Publications

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  • Item
    Design of magneto-rheological brake for optimum dimension
    (Springer Verlag service@springer.de, 2018) Lijesh, L.; Kumar, D.; Gangadharan, K.V.
    Online control of braking performance of magneto-rheological (MR) brake by bridling the apparent viscosity of MR fluid and by amending magnetic field is considered as an effective and smart option to replace the conventional disc brake. The magnetic field procreated by electromagnet in MR brake is reliant on dimensions and material properties of MR brake (casing, rotor and MR fluid region). Extensive works have been reported on enhancing the magnetic properties of MR fluid to achieve maximum braking performance; however, scarce works are available that reflects that the dimensions of MR brake influence the braking performance. Prior works on MR brakes focus on designing for meticulous outer dimensions of brakes, and thus, their results find little utility to a new designer. Therefore, the objective of the present work is to propose a methodology to determine the dimension of MR brake for a given outer dimensions, which shall provide maximum braking performance. The, braking performance is evaluated by assessing the effective torque and brake density. Magneto-static analysis using ANSYS is employed for determining the magnetic field in the MR region, and thereafter, the braking torque is calculated. From the obtained results, curve fit equations are proposed to estimate the values of (i) MR brake casing thickness, (ii) height of the MR brake to rotor, (iii) thickness of core, and (iv) thickness of MR fluid region, for achieving maximum torque. To validate the proposed methodology, MR brake with two different electromagnets and rotors is developed. The static performance of MR brake is evaluated by measuring the braking torque for different currents using a torque wrench and the dynamic performance of the MR brakes is performed on an MR brake test setup. The dynamic performance is evaluated by measuring viscous torque. Finally, the comparisons of the theoretical and experimental results are performed and the obtained results are presented. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.
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    Design and optimization of an external-rotor switched reluctance motor for an electric scooter
    (Elsevier Ltd, 2023) Bhaktha, S.B.; Jogi, A.; Jeyaraj, J.; Gangadharan, K.V.
    In order to reduce the global carbon foot print, the need of the hour is to provide pollution free and economically viable electric vehicles (EVs) as potential alternatives to the conventional ones. Amongst the different traction motors employed in EVs, switched reluctance motors (SRMs) being magnet-free, rugged in construction and fault-tolerant is a potential forerunner for automotive applications in the near future. Therefore, in this work, an external-rotor (ER) SRM has been designed for an electric scooter application. The proposed 4-phase SRM configuration comprises of 8 and 10 poles on the stator and rotor respectively. To achieve a well-balanced design with due consideration to the various performance indicators, a multi-objective design optimization (MOO) has been performed using particle swarm optimization (PSO). The optimization was based on the results obtained from the two-dimensional (2D) electromagnetic static finite element analysis (FEA) which aimed to maximize average torque, efficiency and minimize torque ripple respectively. In comparison to the preliminary design, the optimized ER-SRM demonstrated an increased average torque and decreased copper loss by 3% and 14% respectively. The large scale of simulations performed and the results thereby obtained confirmed that the proposed SRM design met the performance demands of the electric scooter application. The average torque at the rated and the maximum speed exceeded the desired torque requirements demanded by the electric scooter by 13.1% and 42.2% respectively. © 2023
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    Driving Cycle-Based Design Optimization and Experimental Verification of a Switched Reluctance Motor for an E-Rickshaw
    (Institute of Electrical and Electronics Engineers Inc., 2024) Bhaktha, B.S.; Jose, N.; Vamshik, M.; Pitchaimani, J.; Gangadharan, K.V.
    This article deals with the design and optimization of a 2 kW switched reluctance motor (SRM) for an electric rickshaw (E-rickshaw). Previously published research on SRM optimization has mostly focused on the optimization of their design and control variables only at the rated conditions. In electric vehicle (EV) applications, the load operating points (LOPs) of a traction motor are dynamic and spread widely across the torque speed envelope. To enhance their overall performance, it is vital to include them in the design optimization process; therefore, in this article, a novel procedure for implementing the multiobjective design optimization (MODO) of an SRM based on a driving cycle has been demonstrated. Higher starting torque and torque density with reduced electromagnetic losses throughout the driving cycle are established as the design objectives, subject to practical restrictions on current density and slot fill factor. The design objectives have been accurately evaluated through transient finite element analysis (FEA) and a computationally efficient SRM drive model (developed in MATLAB/Simulink) with consideration of the excitation control parameters. Kriging models have been constructed to reduce the computation cost of FEA during the optimization process. Then, a nondominated sorting genetic algorithm II (NSGA II) based multiobjective optimization coupled with the constructed Kriging models is conducted to generate a Pareto front. An optimal design that offers the best balance between the design objectives is selected from the Pareto-optimal set, and the dimensions of corresponding design variables are used to build a prototype. Finally, the static and dynamic performance of the SRM prototype are experimentally evaluated and validated with the FEA simulations. © 2024 IEEE.