Browsing by Author "Singh, B."

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A 36-Pulse AC-DC Converter with DC Side Tapped Interphase Bridge Rectifier for Power Quality Improvement
(2018) Saravana, Prakash, P.; Kalpana, R.; Chethana, K.S.; Singh, B.
This paper presents a circuit configuration to reduce the harmonic contents at the AC mains of a 12-pulse zigzag configured autotransformer based DBR. The proposed circuit configuration employs a tapped interphase bridge rectifier at the DC side of 12-pulse DBR that results in higher pulses in the supply current. Thus, reducing the harmonic content and thereby improving the power quality of the system. Since the autotransformer employed is zigzag configured, the need for ZSBT is eliminated. Moreover, the proposed circuit configuration at the DC side shapes the supply current near to a sine wave. Further, the proposed configuration is analyzed, simulated in MATLAB Simulink and the simulation results are presented, which confirms the improvement in power quality parameters in the input AC line current. Further, the viability of the proposed configuration is verified by experimental results which confirm the suitability of the proposed configuration in AC-DC applications. � 2018 IEEE.
A 20-Pulse Asymmetric Multiphase Staggering Autoconfigured Transformer for Power Quality Improvement
(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.
This letter presents a 20-pulse multiphase staggering autoconfigured transformer (MSAT) for power quality improvement in medium and high power applications. The proposed autoconfigured transformer is a combination of delta and zig-zag transformers. Contrary to the prior art multipulse autoconnected transformers, magnetic rating of the proposed configuration is only 40% of the load rating in addition to improved power quality indices. Moreover, the creation of a neutral point ascribed to inbuilt zig-zag windings supplements as one of the remarkable advantages of the proposed MSAT. Therefore, with this suggested configuration, the performance of zig-zag transformer is accomplished within the autoconfigured transformer. A detailed comparison of the proposed MSAT configuration with that of other multipulse autoconnected transformers in terms of magnetic rating and power quality indices are presented. Further, the feasibility and operability of the proposed MSAT are verified and validated through experimental tests on the laboratory prototype. The test results so obtained complies with the IEEE-519 and IEC 61000-3-2 standards on power quality requirements. © 2017 IEEE.
A 36-Pulse AC-DC Converter with DC Side Tapped Interphase Bridge Rectifier for Power Quality Improvement
(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.S.; Kalpana, R.; Chethana, K.S.; Singh, B.
This paper presents a circuit configuration to reduce the harmonic contents at the AC mains of a 12-pulse zigzag configured autotransformer based DBR. The proposed circuit configuration employs a tapped interphase bridge rectifier at the DC side of 12-pulse DBR that results in higher pulses in the supply current. Thus, reducing the harmonic content and thereby improving the power quality of the system. Since the autotransformer employed is zigzag configured, the need for ZSBT is eliminated. Moreover, the proposed circuit configuration at the DC side shapes the supply current near to a sine wave. Further, the proposed configuration is analyzed, simulated in MATLAB Simulink and the simulation results are presented, which confirms the improvement in power quality parameters in the input AC line current. Further, the viability of the proposed configuration is verified by experimental results which confirm the suitability of the proposed configuration in AC-DC applications. Â© 2018 IEEE.
A 36-Pulse AC-DC Converter with DC-Side Tapped Interphase Bridge Rectifier for Power Quality Improvement
(Institute of Electrical and Electronics Engineers Inc., 2021) P, P.P.; Kalpana, R.; Chethana, K.S.; Singh, B.
This article presents a circuit configuration to reduce the harmonic contents at the ac mains of a 12-pulse zigzag configured autotransformer-based diode bridge rectifier (DBR). The proposed circuit configuration employs a tapped interphase bridge rectifier at the dc side of 12-pulse DBR that results in higher pulses in the supply current, thus reducing the harmonic content and, thereby, improving the power quality of the system. Since the autotransformer employed is zigzag configured, the need for zero-sequence blocking transformer is eliminated. Moreover, the proposed circuit configuration at the dc side shapes the supply current near to a sine wave. Further, the proposed configuration is analyzed, simulated in MATLAB/Simulink, and the simulation results are presented, which confirms the improvement in power quality parameters in the input ac line current. Furthermore, the viability of the proposed configuration is verified by the experimental results that confirm the suitability of the proposed configuration in ac-dc applications. © 1972-2012 IEEE.
A Global Maximum Power Point Tracking Technique of Partially Shaded Photovoltaic Systems for Constant Voltage Applications
(Institute of Electrical and Electronics Engineers Inc., 2019) Goud, J.S.; Kalpana, R.; Singh, B.; Kumar, S.
The P-V characteristics of photovoltaic (PV) array exhibit several maximum power points (MPP) during non-uniform insolation (i.e., during partial shading) conditions; there exists only one global MPP (GMPP), whereas others are referred to local MPP. This paper presents a technique to track the GMPP for the constant voltage or battery loads during partial shading conditions using a single sensor connected to the battery terminals. The proposed method introduces fast and efficient scanning based method, i.e., scanning Ibatt-D curve of power electronic interface at selective duty cycles to recognize the kind of the solar shading pattern (i.e., kind of P-V curve) on PV array and to find the GMPP neighborhood. Moreover, the proposed method overcomes the drawbacks of existing methods such as low convergence speed, increased number of sensors, and heavy computational complexity. The proposed GMPPT method is simulated in MATLAB/Simulink and validated through test results on a prototype for various non-uniform insolation conditions. The results have shown that this paper tracks the GMPP with best tracking efficiency and fast tracking speed. Further, the proposed method is compared with two P-V curve scanning based GMPPT methods and one global optimization based artificial bee colony method. © 2018 IEEE.
A Hybrid Global Maximum Power Point Tracking Technique with Fast Convergence Speed for Partial-Shaded PV Systems
(Institute of Electrical and Electronics Engineers Inc., 2018) Goud, J.S.; Kalpana, R.; Singh, B.
Photovoltaic (PV) systems exhibit multiple local and one global maximum power points (MPPs) in their P -V and I-V curves during partial shading conditions (PSC). Thus, to improve the efficiency of the system, a global maximum power point tracking (GMPPT) algorithm is necessary. This paper presents a hybrid GMPPT algorithm for constant voltage load applications using a single current sensor. The proposed method combines single current sensor hill climbing (SSHC) and artificial bee colony (ABC) algorithms to track the GMPP. The SSHC algorithm detects the event of PSC and tracks the MPP during uniform insolation conditions. The output current of the power electronic interface is measured effectively at selective duty cycles to identify the type of P-V curve pattern and, thus, initiate either SSHC or ABC. The search space for the ABC algorithm is reduced in the proposed technique to improve the convergence speed. The proposed GMPPT technique is simulated in MATLAB and validated through experimental prototypes for various PSCs. The proposed algorithm tracks the GMPP with excellent efficiency and fast speed. © 1972-2012 IEEE.
A Modularized Two-Stage Active Cell Balancing Topology With Reduced Balancing Time for Series Connected Li-Ion Battery String
(Institute of Electrical and Electronics Engineers Inc., 2025) Manjunath, K.; Kalpana, R.; Singh, B.
This paper introduces a modularized two-stage active cell balancing topology utilizing an improved buck-boost converter for a series-connected lithium-ion battery string. The proposed topology adopts a modular structure where each module comprises three cells, two inductors, and four MOSFET switches. The voltage monitoring circuit controls the switches to ensure each cell has same voltage by transferring charge from a source cell to target cell. This approach enables module-to-module balancing through a module equalizer while simultaneously targeting two cells within a module through a cell equalizer. Using modularization technique in the proposed topology, the balancing time is reduced significantly compared to cell equalization circuit. Moreover, using a combination of cell and module balancing, the balancing time is reduced effectively compared with performing cell balancing only under dynamic charging/discharging conditions. This methodology substantially reduces cell equalization time and enhances system performance with minimal components. Proposed topology is verified theoretically and experimentally with a five-module battery string under static and dynamic conditions. © 1972-2012 IEEE.
A non-isolated bidirectional high gain integrated multiport converter for grid tied solar PV fed telecom load
(John Wiley and Sons Inc, 2023) Sheeja, V.; Kalpana, R.; Singh, B.; Subramaniam, U.; Muhibbullah, M.
A multiport converter (MPC) with a non-isolated high gain bidirectional port is proposed for the grid integration of solar photovoltaic array (SPA) fed telecommunication load. The SPA along with a battery energy storage (BES) meets the power demand of the telecom DC load and the excess/deficit power is exchanged with AC grid. The MPC feeds the DC link of a voltage source converter for bidirectional operation with the AC grid. The small signal analysis of the converter shows that its operation is stable. The SPA, BES, and telecommunication load are rated for lower voltages, consecutively reducing the complexity with series-connected SPA. The proposed MPC possesses the merits of high voltage gain, reduced inductor size, and reduced number of components. Moreover, a power flow management algorithm is devised for the proposed converter that regulates the DC voltage at the telecom load and ensures smooth power flow control among various ports. The MPC is able to operate at various modes by controlling the ports independently. The converter performance during steady state and dynamic operating conditions under various modes are analyzed with detailed simulation studies. An experimental prototype is developed and test results are demonstrated to prove the viability of the designed converter. © 2022 The Authors. IET Power Electronics published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
A Nonisolated High Gain Bidirectional DC–DC Converter With Reduced Switch Count: Analysis and Implementation
(Institute of Electrical and Electronics Engineers Inc., 2025) VSheeja, S.; Kalpana, R.; Singh, B.
This article investigates a bidirectional dc–dc converter having a very high voltage gain for grid integration of a microgrid supported by renewable power sources. The proposed converter interfaces the low-voltage solar PV and battery energy storage systems with a high-voltage system. Because of its large voltage gain both in forward and reverse operating modes, the proposed converter can be used at lower and moderate duty ratios. In comparison to previously reported topologies of a similar nature, this converter can provide better performance with fewer switches and passive components, resulting in better efficiency. The input current's ripple is observed to be lowered as a result of the parallel operation of inductors. The converter stability is investigated using state space modeling and small signal analysis. The laboratory hardware prototype confirms the suggested converter's effectiveness for bidirectional operation, and the outcomes are in line with theoretical studies. © 2020 IEEE.
A Reduced Switch Count Switched Capacitor Based High Voltage Gain Bidirectional DC-DC Converter for Grid Integration of BTS
(Institute of Electrical and Electronics Engineers Inc., 2020) Sheeja, V.; Kalpana, R.; Singh, B.
A high voltage gain bidirectional DC-DC converter with reduced switch count is presented in this work. Renewable energy sources such as solar PV array, that are available at low DC voltage, is being used for supporting the DC load of a base transceiver station along with battery energy storage. Hence, the low voltage DC grid system requires a bidirectional DC-DC converter for the bidirectional power flow with the AC grid. This converter has a high gain compared to other existing topologies with reduced active switch count. The performance of it is validated with detailed simulations and a hardware prototype. Moreover, the performance of the system is analyzed and studied for step-up and step-down operations with a solar PV array, BES and a load connected to DC grid. Â© 2020 IEEE.
A Two-Stage Module Based Cell-to-Cell Active Balancing Circuit for Series Connected Lithium-Ion Battery Packs
(Institute of Electrical and Electronics Engineers Inc., 2023) Manjunath, K.; Kalpana, R.; Singh, B.; Kiran, R.
This article addresses a two-stage module based cell-to-cell active equalization topology based on a modified buck-boost converter for series connected Lithium-ion battery packs. In the proposed topology, initially module based equalizing currents are controlled. Subsequently, cell-based equalizers are controlled in parallel within each battery module. The proposed topology significantly reduces the balancing time by transferring higher balancing current from a strong cell to the weakest cell in a module directly. With the proposed topology's modularized design, reduces voltage stress on long strings of switches, resulting in improved performance with fewer components. The operating principle, control strategy and design constraints are analyzed in detail. The MATLAB/Simulink platform is utilized to demonstrate the feasibility of the proposed technique for balancing the energy in series connected battery cells. To reduce the complexity of the control approach, the digital control is implemented using an FPGA control board. Further, a laboratory prototype is developed to show the feasibility and operability of the proposed topology. © 1986-2012 IEEE.
An analytical model for intersystem handover
(Institute of Electrical and Electronics Engineers Inc., 2003) Singh, B.; Aggarwal, K.K.; Kumar, S.
Universal Mobile Telecommunication Systems (UMTS) shall be developed in such a way that it will support compatibility with an evolved Global System for Mobile Communications (GSM). In this paper, we investigate intersystem handover between GSM and UMTS based on Wideband Code Division Multiple Access (WCDMA) air-interface. A mathematical model is proposed to evaluate the handover performance. The handover initiation algorithm is based on the absolute value of averaged signal strength thresholds. Average number of handovers and handover initiation delay are used as performance measures. Based on numerical results, it is observed that handover initiation algorithm based on absolute thresholds induces large number of handovers near the cell boundary. Finally, threshold levels are optimized for given system parameters.
An improved power quality converter for three-phase switched mode power supplies
(IEEE Computer Society help@computer.org, 2014) Kalpana, R.; Singh, B.; Bhuvaneswari, G.
In this paper, an improved power quality converter is presented for harmonic mitigation in SMPS (Switched Mode Power Supply) for telecom power applications with reduced kVA rating. The proposed ac-dc converter is found capable of suppressing less than 23rd harmonic in the supply current along with the power factor improvement close to unity in the wide operating range. The effect of load variation on the SMPS is studied to demonstrate the performance and effectiveness of the improved converter. Â© 2014 IEEE.
An Online Method of Estimating State of Health of a Li-Ion Battery
(Institute of Electrical and Electronics Engineers Inc., 2021) Goud, J.S.; Kalpana, R.; Singh, B.
Li-ion batteries are playing a crucial role in the fields of renewable energy systems and electric vehicles. The reliability of these systems depends on a battery management system (BMS) which monitors the state of charge (SoC) and state of health (SoH) effectively. Knowing the SoH of a battery in advance enhances the system reliability. This article proposes an accurate online estimation of SoH of a Li-ion battery integrated in solar photovoltaic system (SPV) applications. The proposed method uses the modified coulomb counting method to estimate the SoH of a battery. The proposed SoH estimation method is simulated in MATLAB/Simulink by considering the aging factors such as temperature, charge/discharge rates and depth of discharge. Moreover, the proposed method is validated using an experimental prototype and the results are found to be satisfactory. © 1986-2012 IEEE.
An analytical model for intersystem handover
(2003) Singh, B.; Aggarwal, K.K.; Kumar, S.
Universal Mobile Telecommunication Systems (UMTS) shall be developed in such a way that it will support compatibility with an evolved Global System for Mobile Communications (GSM). In this paper, we investigate intersystem handover between GSM and UMTS based on Wideband Code Division Multiple Access (WCDMA) air-interface. A mathematical model is proposed to evaluate the handover performance. The handover initiation algorithm is based on the absolute value of averaged signal strength thresholds. Average number of handovers and handover initiation delay are used as performance measures. Based on numerical results, it is observed that handover initiation algorithm based on absolute thresholds induces large number of handovers near the cell boundary. Finally, threshold levels are optimized for given system parameters.
Application of voltage multiplier in 12-pulse rectifier for sinusoidal input current
(Institution of Engineering and Technology journals@theiet.org, 2018) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.
A DC current injection circuit of a trifurcated autotransformer (TAT)-based 12-pulse diode bridge rectifier (DBR) is proposed which can help reduction of harmonics in the AC mains. The circuit at the DC side employs a voltage multiplier (VM) circuits namely voltage doubler, voltage tripler and voltage quadrupler and an interphase transformer which provides the required circulating current. This induced circulating current shapes the input AC line current near to a sine wave. The output of VM circuits is connected across the load and thereby reuses the harmonic energy absorbed by the system. Thus, improves the energy conversion efficiency of the proposed system. The TAT-based 12-pulse DBR has the implicit ability to prevent the zero sequence components thus expels the necessity of zero sequence blocking transformer. The proposed configuration is analysed, simulated in MATLAB Simulink and the simulation results are presented, which confirms the improvement in power quality parameters in the input AC line current. Further, the viability of the proposed configuration is verified by experimental results which confirm the suitability of the proposed configuration in AC-DC applications. © 2018 Springer Verlag. All rights reserved.
Current injection based front-end power quality improved converter for telecom load
(2017) Saravana, Prakash, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.
In this paper a front-end converter having third harmonic current injection technique is used for improving input current shape as near sinusoidal. Here zig-zag transformer is used as the current injection device so that the advantages pertaining to zig-zag transformer is utilized effectively. The third harmonic current injection device along with the three-level boost converter at the output stage will increase the dc-link voltage and the current is injected through zig-zag transformer. The power quality is well improved using third harmonic current modulated front-end structure which is very well applicable to telecom load having the high current low voltage. Extensive simulation is carried out for the 12 kW load and the results are verified through experimental setup. The experimental setup is tested for reduced voltage rating and the test results are presented. � 2016 IEEE.
Current injection based front-end power quality improved converter for telecom load
(Institute of Electrical and Electronics Engineers Inc., 2017) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.
In this paper a front-end converter having third harmonic current injection technique is used for improving input current shape as near sinusoidal. Here zig-zag transformer is used as the current injection device so that the advantages pertaining to zig-zag transformer is utilized effectively. The third harmonic current injection device along with the three-level boost converter at the output stage will increase the dc-link voltage and the current is injected through zig-zag transformer. The power quality is well improved using third harmonic current modulated front-end structure which is very well applicable to telecom load having the high current low voltage. Extensive simulation is carried out for the 12 kW load and the results are verified through experimental setup. The experimental setup is tested for reduced voltage rating and the test results are presented. Â© 2016 IEEE.
Design and analysis of solar photovoltaic array fed modular full-bridge DC-DC converter for 12 kW SMPC
(2018) Prakash, P.S.; Kalpana, R.; Singh, B.
This paper discusses the solar photovoltaic (SPV) array fed switched mode power converter (SMPC) using a modular full-bridge dc-dc converter as an intermediate converter. Among the different types of dc-dc converters, the straightforward and uncomplicated boost converter is selected in order to obtain the maximal power from the SPV array. The straightforward boost converter with reduced part count has inherent features of minimizing the output current ripples and possessing an unbounded region for maximum power point extraction. The improved efficiency of the converter is achieved by designing the SPV array to deliver maximum power at rated dc voltage and maximum switch utilization of the boost converter. The design, analysis and operating modes are explained for the proposed converter and the performance is validated through MATLAB/Simulink based simulation. � 2017 IEEE.
Design and analysis of solar photovoltaic array fed modular full-bridge DC-DC converter for 12 kW SMPC
(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.S.; Kalpana, R.; Singh, B.
This paper discusses the solar photovoltaic (SPV) array fed switched mode power converter (SMPC) using a modular full-bridge dc-dc converter as an intermediate converter. Among the different types of dc-dc converters, the straightforward and uncomplicated boost converter is selected in order to obtain the maximal power from the SPV array. The straightforward boost converter with reduced part count has inherent features of minimizing the output current ripples and possessing an unbounded region for maximum power point extraction. The improved efficiency of the converter is achieved by designing the SPV array to deliver maximum power at rated dc voltage and maximum switch utilization of the boost converter. The design, analysis and operating modes are explained for the proposed converter and the performance is validated through MATLAB/Simulink based simulation. Â© 2017 IEEE.