Faculty Publications
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Publications by NITK Faculty
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Item New direct torque and flux control with improved torque per ampere for switched reluctance motor(Institute of Electrical and Electronics Engineers Inc., 2019) Pittam, K.R.; Ronanki, D.; Parthiban, P.; Williamson, S.S.Inherent torque ripple, acoustic noise and vibration are the major hindrances of switched reluctance motor (SRM)for wide acceptance in the automotive industry. To avoid stability issues in electrified vehicles, smooth torque control of an SRM is requisite. Torque ripple in the SRM can be avoided by proper machine design and/or directly controlling the torque. To maintain the torque within the hysteresis band in the conventional direct torque and flux control (DTFC), a high value of RMS current flows through the motor windings. This results in an increase in copper losses and reduces the net torque per ampere ratio. This paper addresses this issue by proposing a new DTFC technique for an SRM drive with the features of improved torque per ampere while maintaining the torque within the hysteresis bands. MATLAB simulations show that the proposed DTFC technique enhances torque per ampere ratio while minimizing the torque ripple. The effectiveness of the proposed DTFC strategy is also demonstrated through real-time simulations in the OPAL-RT digital platform. Real-time results show that the proposed DTFC strategy exhibits better performance in comparison to the conventional DTFC under steady-state and dynamic conditions. © 2019 IEEE.Item Torque Ripple Minimization of Four-phase Switched Reluctance Motor using Direct Torque Control with an Innovative Switching Sequence Scheme(Institute of Electrical and Electronics Engineers Inc., 2019) Pittam, P.K.; Ronanki, D.; Parthiban, P.; Beig, A.R.; Williamson, S.S.Direct torque control (DTC) technique is the prominent control strategy, used to control the switched reluctance motor (SRM) with a reduced torque ripple in comparison to the traditional current control techniques. However, it draws higher phase current in order to maintain the required electromagnetic torque during phase commutation, thus reduces torque per ampere. To circumvent this issue, a new DTC method with an innovative switching sequence is introduced in this paper, which minimizes torque ripple as well as power loss. The efficacy of the proposed scheme is validated for four-phase SRM through detailed simulation studies and compared with the conventional DTC scheme. The results show that the proposed scheme exhibits an improved steady-state as well as dynamic performance under various operating conditions. © 2019 IEEE.Item Phase current reconstruction algorithm for four-phase switched reluctance motor under direct torque control strategy(Institute of Electrical and Electronics Engineers Inc., 2021) Ronanki, D.; Pittam, K.R.; Dekka, A.; Parthiban, P.; Beig, A.R.Existing phase current reconstruction algorithms are developed for switched reluctance motor (SRM) operated under current chopping control (CCC), which generates high torque ripple. Therefore, the direct torque control (DTC) technique is mostly used to control the SRM with minimal torque pulsations. However, the reconstruction of phase currents using the existing one or two sensor methods developed under CCC control will be more difficult to adopt for the DTC scheme due to the simultaneous conduction of all phases. To circumvent this issue, a novel DTC method with reduced sensors is introduced in this paper, which exhibits better performance in comparison to the conventional DTC method. The proposed DTC method avoids the long tail currents thereby limits the conduction of all phases simultaneously. The efficacy of the proposed scheme is validated for four-phase SRM through MATLAB simulations. The results show that the proposed approach helps to operate the drive at the lower torque ripple with reduced cost under various operating conditions in comparison to the conventional DTC. © 2021 IEEE.Item 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. © 2023Item 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.Item A Systematic Approach to Digital Control Development for Four-Phase SRM Drive Using Single Current Sensor for Medium Power Applications(Institute of Electrical and Electronics Engineers Inc., 2024) Ali, T.F.; Dominic D, D.A.; Prabhakaran, P.In the realm of medium-power high-volume applications, Switched Reluctance Motor (SRM) drives hold great advantages over other motors. However, the SRM drive must be optimized to reduce cost without compromising the performance for medium power applications. This paper presents a novel SRM drive utilizing a Miller converter-fed SRM motor with a single current sensor, offering a comprehensive control development procedure encompassing system modeling, design procedures, dynamic simulation, analysis, and experimental validation. The SRM is characterized through finite element analysis (FEA) to derive a MATLAB Simulink simulation model, and the conduction angle is optimized for drive efficiency through parametric simulation studies. The linear SRM model for control design is obtained via small signal analysis. Speed and current controllers are designed using the K-factor method, and the efficacy of the proposed drive is rigorously evaluated across various operating modes in MATLAB Simulink. Additionally, a hardware prototype is developed and the digital control algorithm is implemented on the DSP microcontroller TMS320F28379D based on the designed controllers to further assess drive performance. The results obtained validate the robustness and dynamic performance of the SRM drive across variable speed, variable torque, and constant power modes of operation. © 2013 IEEE.Item Fault-Tolerant Operation of Switched Reluctance Motor Using Cascaded Current and PWM Control With Effect of Commutation Angle Variation(Institute of Electrical and Electronics Engineers Inc., 2024) Reddy, J.S.; Parthiban, P.This paper presents a proposed fault-tolerant control strategy for Switched Reluctance Motor (SRM) drives, utilizing cascaded current and pulse width modulation (PWM) control mechanisms with commutation angle variation. The study systematically evaluates the mechanical performance of SRM drives by regulating voltage and current to achieve robust dynamic response under various fault conditions. Optimal commutation angles are identified to enhance operational efficiency and balance performance under fault scenarios. The comprehensive simulations use a 4 kW, 4 φ, 8/6 SRM model in MATLAB/Simulink; further, real-time experiments are conducted using FPGA-based modelling with a Controller Hardware-in-Loop (CHIL), setup on the OPAL-RT 4510 platform. The proposed control technique demonstrates high fault tolerance and reliable mechanical performance, making it suitable for variable-speed drive applications. The findings underscore the potential of the proposed control strategy to ensure the robust operation of SRM drives in practical implementations, highlighting its significance for enhancing the reliability and efficiency of electric drive systems. © 1972-2012 IEEE.Item Analyzing the Performance of Fault-Tolerant Switched Reluctance Motor Control Strategies With Novel Commutation Angle Variation(Institute of Electrical and Electronics Engineers Inc., 2024) Santhosh Reddy, J.; Parthiban, P.This paper analyzes control techniques using a novel commutation angle variation for fault-tolerant operation in Switched Reluctance Motor (SRM) drives. It explores the use of hard chopping hysteresis current control (HCC) and pulse width modulation (PWM), and proposes a cascaded current and PWM technique for fault-tolerant SRM drive operation. The HCC method is most effective for low-speed operations with higher external loads, while the PWM method is suitable for medium to high-speed operations but it can't control current effectively at high external loads. The proposed control technique approach is developed to address the limitations of HCC and PWM methods, by combining current and PWM methods with optimized commutation angle control. This approach effectively controls current and variable speed operations even under fault conditions. This paper evaluates control strategies by varying commutation angles to determine the optimized angles that ensure balanced performance and better operation under fault conditions. This paper assesses the mechanical performance under light and high external loading conditions at optimized commutation angles during open circuit fault conditions. Simulation studies are conducted using a 4 kW, 4-phase, 8/6 SRM configuration on the MATLAB/Simulink platform. Additionally, real-time FPGA-based modelling experiments are performed using a Controller Hardware-in-Loop (CHIL) setup on the OPAL-RT 4510 platform. The performance analysis highlights the importance of identifying the best control techniques to ensure high fault tolerance and reliable mechanical performance, making this approach promising for variable-speed drive systems. The findings of this study significantly advance fault-tolerant SRM control techniques, enhancing their suitability for various industrial applications. © 2013 IEEE.