Browsing by Author "Ronanki, D."

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A fixed frequency duty-ratio based digital sliding-mode controller for DC-DC buck converter
(American Scientific Publishers, 2018) Parthiban, P.; Ronanki, D.; Kiran, B.
The hysteresis modulation (HM) based sliding mode control (SMC) implementation results in variable frequency, where the converter's operating frequency cannot be measured accurately. This will have a negative impact on circuit component and filter design. Furthermore, it is sensitive to the disturbances and the parameter uncertainties. To maintain constant switching frequency during line and load regulation, a duty-ratio (DR) based sliding-mode (SM) control approach is proposed in this paper and applied to a DC-DC buck converter. The translation of the SM control law for HM and DR scheme implementation by using field programmable gate array (FPGA) for DC-DC buck converter is illustrated. A simple and self-explanatory design and implementation procedure are also addressed. The performance and robustness of the proposed DR-based SM controllers are validated by both simulation results using MATLAB/Simulink and experimental results. The robustness of the SM controller is tested at various operating conditions and compared the results with HM-based SM and conventional linear controller. © 2018 American Scientific Publishers All rights reserved.
A small 4-wheeler EV propulsion system using DTC controlled induction motor
(2013) Ronanki, D.; Hemasundar, A.; Parthiban, P.
With the increasing need of electric vehicles (EV), necessary development is required to get reliable, efficient and economical drives for electric propulsion. Electric propulsion system using Induction Motor drive (IM) is becoming so popular because of its reliability, technological maturity and low cost. Field Orientation Control (FOC) is so popular in controlling the IM, but it has disadvantages like sensitive to parametric variation, external disturbance, load variation and also algorithm takes more time for execution, hence it requires a very fast microprocessor with high millions of instructions per second (MIPS) for implementation. In this paper, IM is controlled by using Direct Torque Control (DTC) technique because of its simple configuration and gives quick response. The mathematical model takes into account of the inverter, IM dynamics and vehicle aerodynamics. In this paper, the response of the IM with DTC for EV load for driving cycle consists of starting, acceleration, constant speed and deceleration modes are explained and validated using MATLAB/SIMULINK.
A SVPWM for reduction in common mode and bearing currents applied to diode clamped three-level inverter fed induction motor
(Institute of Electrical and Electronics Engineers Inc., 2016) Ronanki, D.; Parthiban, P.
PWM inverters used in motor drives produce high frequency Common Mode Voltages (CMV) which results in Common Mode (CM) currents and bearing currents due to parasitic capacitances. These currents cause abominable effects in electronics devices and develop voltage at motor shaft. When voltage exceeds dielectric breakdown voltage of lubricant film, it develops a huge bearing current which can damage bearings in very short interval. This paper emphasis on mitigation of CM currents and bearing currents by minimizing CMV produced by inverter-motor system based on selection and refinement of PWM algorithm without any additional hardware change. Multilevel inverters are apt for industrial applications due to low voltage distortion and less stress on switching devices than conventional two level inverter. To Investigate the effects on CMV, CM currents, bearing currents and motor shaft voltage, a high frequency Induction Motor (IM) model was chosen and analysis was done with different PWM techniques. The present work focused on three level Diode Clamped MultiLevel Inverter (DCMLI) and proposed new Space vector Pulse width Modulation (SVPWM) by choosing reductant CMV vectors in combination with sequence of changing one state in phase during switching transition. The proposed SVPWM technique shows the effectiness to reduce CMV as well as Electro-Magnetic Interference (EMI) and validated using MATLAB simulations. Â© 2016 IEEE.
Design methodology and sensorless control of electric propulsion system using DTC-SVM
(2017) Perumal, P.; Ronanki, D.
Electric propulsion system (EPS) employing Induction Motors (IM) have gained acceptance due to their robust structure, reliability, technological advancement and low cost. This paper presents the technical considerations and design methodology of EPS for urban cars. Direct torque control (DTC) is a prominent technique in controlling the IM due to its easy configuration and fast performance. Nevertheless, it generates high torque ripple coupled with variable switching frequency. To get sophisticated results like ripple free torque and constant switching frequency, IM can be controlled by DTC scheme using the space-vector modulation (SVM) technique. The speed of the motor is estimated in limp-home mode operation of the vehicle by rotor flux based model reference adaptive system (MRAS). The performance of IM in limp-home mode of electric vehicle using DTC and DTC-SVM techniques considering the drive cycle are presented. � 2017 IEEE.
Design methodology and sensorless control of electric propulsion system using DTC-SVM
(Institute of Electrical and Electronics Engineers Inc., 2017) Parthiban, P.; Ronanki, D.
Electric propulsion system (EPS) employing Induction Motors (IM) have gained acceptance due to their robust structure, reliability, technological advancement and low cost. This paper presents the technical considerations and design methodology of EPS for urban cars. Direct torque control (DTC) is a prominent technique in controlling the IM due to its easy configuration and fast performance. Nevertheless, it generates high torque ripple coupled with variable switching frequency. To get sophisticated results like ripple free torque and constant switching frequency, IM can be controlled by DTC scheme using the space-vector modulation (SVM) technique. The speed of the motor is estimated in limp-home mode operation of the vehicle by rotor flux based model reference adaptive system (MRAS). The performance of IM in limp-home mode of electric vehicle using DTC and DTC-SVM techniques considering the drive cycle are presented. Â© 2017 IEEE.
Direct Instantaneous Torque Control of Five-Phase Segmented Switched Reluctance Motor with Bipolar Excitation for In-Wheel Electric Vehicles
(Institute of Electrical and Electronics Engineers Inc., 2020) Ronanki, D.; Dekka, A.; Parthiban, P.; Beig, A.R.
Multi-phase segmented switched reluctance motors (SRMs) are the better option for in-wheel electric vehicles due to higher specific torque (70% more) and torque density than conventional toothed SRMs. Furthermore, it allows to excite two or more phases simultaneously in order to avoid torque dips during the phase commutations. However, conventional control schemes cause severe torque pulsations. In this paper, a new direct instantaneous torque control technique for a five-phase segmented SRM (SSRM) with bipolar excitation is proposed. SSRM is fed by the five-phase voltage source inverter (VSI) instead of a conventional asymmetric H-bridge (AHB) converter. The performance of the proposed control algorithm is validated through MATLAB simulations. Results show that the proposed control scheme exhibits an improved performance under a vehicle load. Â© 2020 IEEE.
Direct torque and flux control of switched reluctance motor with enhanced torque per ampere ratio and torque ripple reduction
(Institution of Engineering and Technology JBristow@theiet.org, 2019) Krishna Reddy, P.; Ronanki, D.; Parthiban, P.
A smooth torque control of switched reluctance motor (SRM) is essential to avoid speed fluctuations causing stability problems in vehicular applications. This can be accomplished by an appropriate motor design and/or use of direct control of torque in SRM. It is reported that high RMS current is required to minimise the torque ripple in the conventional direct torque and flux control (DTFC), thereby reducing the torque per ampere ratio. To overcome this issue, a new DTFC technique with improved torque per ampere ratio while minimising torque ripple in an SRM traction drive is presented. Results demonstrated that the proposed DTFC technique reduces torque ripple with enhanced torque per ampere. Finally, the performance of the proposed scheme is compared with conventional DTFC of a four-phase (8/6) SRM to show the improvement in the traction drive. © The Institution of Engineering and Technology 2019
Efficiency improvement and torque ripple minimisation of four-phase switched reluctance motor drive using new direct torque control strategy
(Institution of Engineering and Technology kvukmirovic@theiet.org, 2020) Pittam, P.K.; Ronanki, D.; Parthiban, P.
The direct torque control (DTC) strategy is one of the most effective techniques, used to control the switched reluctance motor (SRM) with improved dynamic performance and reduced torque ripple. However, this approach draws a higher source current due to an extension of the phase current into the negative torque region, which lowers the net torque per ampere ratio. This study proposes a new DTC strategy for SRM to overcome this issue by modifying the partition of the sectors and appropriate voltage vector selection. Therefore, the proposed method improves the drive efficiency while minimising torque ripple. To implement this method, a non-linear machine model is developed using the torque and flux characteristics obtained from experimental studies on a four-phase 8/6 SRM. The proposed DTC scheme is implemented on a digital control platform and power loss calculations are performed to evaluate the drive efficiency. Test results show that the proposed DTC method has improved performance in terms of efficiency and torque ripple under various operating conditions in comparison to the conventional DTC strategy. © The Institution of Engineering and Technology 2019.
New direct torque and flux control with improved torque per ampere for switched reluctance motor
(2019) Pittam, K.R.; Ronanki, D.; Perumal, 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.
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. Â© 2019 IEEE.
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. Â© 2021 IEEE.
Phase Current Reconstruction Method With an Improved Direct Torque Control of SRM Drive for Electric Transportation Applications
(Institute of Electrical and Electronics Engineers Inc., 2022) Ronanki, D.; Pittam, K.R.; Dekka, A.; Parthiban, P.; Beig, A.R.
Acquisition of the accurate phase currents is indispensable for the control and protection of switched reluctance motor (SRM) drives for electric transportation applications. Existing phase current reconstruction techniques for SRM are implemented under the current control techniques, which generate large torque pulsations. Therefore, the direct torque control (DTC) method can be adopted to minimize torque pulsations and to enhance transient performance in electrified vehicles. However, the existing current estimation methods cannot be applied to DTC strategies due to the simultaneous conduction of all phases at any switching instant. Furthermore, it offers a lower torque per ampere ($T/A$) ratio and draws a high source current. This article addresses the aforementioned concerns by proposing a cost-effective phase current reconstruction method with an improved DTC strategy for a 4-kW four-phase SRM drive. This method employs a 16-sector partition method with a new voltage vector selection by detecting zero-current regions of each phase. As a result, the long-tail currents can be avoided, thereby limiting the simultaneous conduction of all phases. The simulation and test results show that the proposed DTC has minimal torque pulsations, high $T/A$ ratio, low converter losses, and lower source current ripple in comparison to the existing DTC schemes under various operating conditions. Also, the proposed phase current estimation method effectively reconstructs the phase currents under both steady-state and transient operating conditions. © 1972-2012 IEEE.
PV-battery powered direct torque controlled switched reluctance motor drive
(2012) Ronanki, D.; Parthiban, P.
Categorized as one of the renewable energies, Photo-Voltaic system has a great potential compared to its counterparts of renewable energies. This paper deals with the design of a Photovoltaic (PV)-Battery fed Switched Reluctance Motor(SRM). The system mainly composed of a PV module, boost converter, rechargeable battery, bidirectional converter, asymmetric bridge converter, SRM and system controllers. The main problems of SRM are high torque ripple, acoustic noise and vibration problems. In order to reduce these problems, a new direct torque control of 3.5 kW 8/6 SRM is proposed, which is simple and can be implemented with low cost processor. It can be seen from the simulation results that this scheme has well regulated the torque output of the motor with in hysteresis band. The proposed system assures its suitability for solar applications like solar vehicles, solar water pumping system and floor mills in hilly and isolated areas. � 2012 IEEE.
PV-battery powered direct torque controlled switched reluctance motor drive
(2012) Ronanki, D.; Parthiban, P.
Categorized as one of the renewable energies, Photo-Voltaic system has a great potential compared to its counterparts of renewable energies. This paper deals with the design of a Photovoltaic (PV)-Battery fed Switched Reluctance Motor(SRM). The system mainly composed of a PV module, boost converter, rechargeable battery, bidirectional converter, asymmetric bridge converter, SRM and system controllers. The main problems of SRM are high torque ripple, acoustic noise and vibration problems. In order to reduce these problems, a new direct torque control of 3.5 kW 8/6 SRM is proposed, which is simple and can be implemented with low cost processor. It can be seen from the simulation results that this scheme has well regulated the torque output of the motor with in hysteresis band. The proposed system assures its suitability for solar applications like solar vehicles, solar water pumping system and floor mills in hilly and isolated areas. Â© 2012 IEEE.
Simulation of SVPWM based FOC of CSI fed induction motor drive
(2012) Ronanki, D.; Rajesh, K.; Parthiban, P.
The application of current source inverters (CSI)in induction motor (IM) drives offers a number of advantages, including voltage boosting capability, natural shoot-through short-circuit protection and generation of sinusoidal voltages. In this paper, an attempt to model the CSI fed IM drive is presented. The mathematical model takes into account of the inverter, and induction motor dynamics and is established in the stationary reference frame. For controlling the drive speed, a direct field-oriented control (FOC) is proposed. To counter the effects of torque pulsations at very low speeds and the rotor resistance variation, a slip angle compensation loop is included in the control law formulation. Analytical expressions for CSI fed IM with Direct FOC are derived and validated using MATLAB/SIMULINK. � 2012 IEEE.
Simulation of SVPWM based FOC of CSI fed induction motor drive
(2012) Ronanki, D.; Rajesh, K.; Parthiban, P.
The application of current source inverters (CSI)in induction motor (IM) drives offers a number of advantages, including voltage boosting capability, natural shoot-through short-circuit protection and generation of sinusoidal voltages. In this paper, an attempt to model the CSI fed IM drive is presented. The mathematical model takes into account of the inverter, and induction motor dynamics and is established in the stationary reference frame. For controlling the drive speed, a direct field-oriented control (FOC) is proposed. To counter the effects of torque pulsations at very low speeds and the rotor resistance variation, a slip angle compensation loop is included in the control law formulation. Analytical expressions for CSI fed IM with Direct FOC are derived and validated using MATLAB/SIMULINK. Â© 2012 IEEE.
A small 4-wheeler EV propulsion system using DTC controlled induction motor
(2013) Ronanki, D.; Hemasundar, A.; Parthiban, P.
With the increasing need of electric vehicles (EV), necessary development is required to get reliable, efficient and economical drives for electric propulsion. Electric propulsion system using Induction Motor drive (IM) is becoming so popular because of its reliability, technological maturity and low cost. Field Orientation Control (FOC) is so popular in controlling the IM, but it has disadvantages like sensitive to parametric variation, external disturbance, load variation and also algorithm takes more time for execution, hence it requires a very fast microprocessor with high millions of instructions per second (MIPS) for implementation. In this paper, IM is controlled by using Direct Torque Control (DTC) technique because of its simple configuration and gives quick response. The mathematical model takes into account of the inverter, IM dynamics and vehicle aerodynamics. In this paper, the response of the IM with DTC for EV load for driving cycle consists of starting, acceleration, constant speed and deceleration modes are explained and validated using MATLAB/SIMULINK.
A SVPWM for reduction in common mode and bearing currents applied to diode clamped three-level inverter fed induction motor
(2016) Ronanki, D.; Perumal, P.
PWM inverters used in motor drives produce high frequency Common Mode Voltages (CMV) which results in Common Mode (CM) currents and bearing currents due to parasitic capacitances. These currents cause abominable effects in electronics devices and develop voltage at motor shaft. When voltage exceeds dielectric breakdown voltage of lubricant film, it develops a huge bearing current which can damage bearings in very short interval. This paper emphasis on mitigation of CM currents and bearing currents by minimizing CMV produced by inverter-motor system based on selection and refinement of PWM algorithm without any additional hardware change. Multilevel inverters are apt for industrial applications due to low voltage distortion and less stress on switching devices than conventional two level inverter. To Investigate the effects on CMV, CM currents, bearing currents and motor shaft voltage, a high frequency Induction Motor (IM) model was chosen and analysis was done with different PWM techniques. The present work focused on three level Diode Clamped MultiLevel Inverter (DCMLI) and proposed new Space vector Pulse width Modulation (SVPWM) by choosing reductant CMV vectors in combination with sequence of changing one state in phase during switching transition. The proposed SVPWM technique shows the effectiness to reduce CMV as well as Electro-Magnetic Interference (EMI) and validated using MATLAB simulations. � 2016 IEEE.
Torque Ripple Minimization of Four-phase Switched Reluctance Motor using Direct Torque Control with an Innovative Switching Sequence Scheme
(2019) Pittam, K.R.; Ronanki, D.; Perumal, 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.
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. Â© 2019 IEEE.