Browsing by Author "P, P."

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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 Critical Review of MPPT Algorithms for PV Systems
(Institute of Electrical and Electronics Engineers Inc., 2024) P, P.; Anusha, R.; Kumar, V.V.; Balasubramanian, B.
With the growing population, one of the main issues is electricity. Electrical power can be generated from a variety of conventional or non-renewable and non-conventional or renewable energy resources. However, there are negative effects of using non-renewable energy resources on both the environment and the human population. Searching for an alternate energy source is necessary due to the limited availability of these fossil fuels. Among the alternatives that can be used to generate electricity are renewable energy resources that transform energy from the sun, wind, falling water, etc. Solar energy is one among these energy resources that is available in abundant. The fundamental components of photovoltaic (PV) systems are solar cells, which are connected in parallel and series to produce the necessary amount of power. There is only one peak in the PV panel characteristics when all the panels receive the same amount of insolation. However, PV systems commonly experience non-uniform insolation due to shadowing. Their power-voltage (P-V) curve show several peaks under these circumstances, with a single global maximum power point (GMPP) among all. Operating these panels at GMPP during partial shading conditions (PSC) is a challenging task as the insolation keeps changing frequently. This study gives a detailed review of various maximum power point tracking (MPPT) methods that is used during uniform and PSC. This review will help the researchers to explore the possibility of choosing best alternative MPPT techniques to be incorporated for commercial purpose. Â© 2024 IEEE.
A Novel Algorithm Based on Voltage and Current Perturbation to Track Global Peak Under Partial Shading Conditions
(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Koothu Kesavan, K.K.; Balasubramanian, B.
Under partial shading conditions, photovoltaic (PV) systems exhibit multiple peaks in their power-voltage (P-V) characteristics. It is essential to extract maximum energy from the PV system. The global maximum power point tracking (GMPPT) algorithms presented in the literature, track the global peak using different methods. It is imperative to have minimal convergence time for GMPPT process. This paper proposes a novel algorithm to track the global peak using voltage and current perturbation. The new GMPPT algorithm operates in a current perturbation or voltage perturbation mode, based on the value of a control variable. In either mode, the proposed technique generates reference current or reference voltage, for navigating the operating point to GMPP location. The proposed algorithm is compared with two GMPPT algorithms, namely, modified maximum power trapezium (M-MPT) and high-performance GMPPT algorithms. The simulation studies are performed in MATLAB and is validated using a laboratory prototype, with dSPACE 1202 MicroLabBox controller for implementing GMPPT methods. Simulation and experimental results show that the new technique exhibits superior performance in terms of tracking time. Also, the energy efficiency is improved by 40% while using the proposed GMPPT algorithm for the irradiance profiles considered in this paper compared to the other two techniques. © 1986-2012 IEEE.
A Novel Cubic Boost Converter With Continuous Source Current for PV Applications
(Institute of Electrical and Electronics Engineers Inc., 2024) Srinivas, B.; P, P.; Nagendrappa, H.; Balasubramanian, B.
A converter with high voltage gain is generally necessary for interfacing the photovoltaic (PV) systems with grid. However, more semiconductor components are needed to obtain a higher voltage gain, which results in increased losses. This brief proposes a novel non-isolated cubic boost (NNICB) DC-DC converter for high-voltage PV applications with a wide voltage gain at a lower duty ratio. Compared to traditional high-gain DC-DC converter, the NNICB converter counters the drawbacks of increased component count and high voltage stress. The NNICB DC-DC converter has a continuous source current for PV applications with low-voltage stress across the diodes and switches. A detailed steady-state analysis of the NNICB topology is carried out for the ideal and non-ideal models, and their corresponding voltage gain equations are computed. Furthermore, the analysis is performed using MATLAB/Simulink and is validated using a 230 W laboratory prototype. The experimental results show that the efficiency of the proposed NNICB topology is 94.42% with a voltage gain of 10.5 at 45% duty ratio. This proves the superior performance of the proposed novel converter in comparison with the existing topologies. © 2004-2012 IEEE.
A Novel Seven-Level Triple-Boost Inverter for Grid-Integrated Photovoltaic Systems
(Springer, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; P, P.
Transformer-less switched-capacitor-based multilevel inverters (TL-SCMLIs) are increasingly preferred for photovoltaic (PV) applications due to their voltage boosting capability, high efficiency, reduced dv/dt stress, and lower cost. However, existing SC-based multi-level inverters often require more components, suffer from leakage currents, have lower boost gain capability, have higher PU total standing voltage, and exhibit lower efficiency. To address these challenges, this paper proposes a novel seven-level switched-capacitor (SC)-based TL-MLI with higher voltage boosting gain and a common ground (CG) configuration for improved performance in grid-tied PV applications. A proportional-integral (PI) controller is designed for the grid-tied seven-level PV inverter, and its performance is evaluated through simulation studies and hardware-in-the-loop (HIL) experimental verification. Finally, a detailed comparative analysis with existing multi-level inverters highlights the proposed seven-level inverter’s advantages, including leakage current reduction, high boost gain, lower cost, lower PU total standing voltage, lower voltage stress, lower peak inverse voltage, and improved efficiency. The total harmonic distortion (THD) of the grid current is less than 5% for the proposed grid-tied seven-level inverter. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025.
A Novel Two Five-Level Double-Boost Inverters for Grid-Tied Photovoltaic Applications
(Springer, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; P, P.
This paper proposes two novel five-level inverters, both featuring a common ground configuration and double-boosting capability. The common ground configuration in the proposed topologies effectively eliminates leakage current, making them ideal for grid-connected photovoltaic applications. The first proposed inverter topology consists of a single DC source, six power switches, two diodes, two capacitors, and one charging inductor. The second topology also uses a single DC source but comprises seven power switches, one diode, two capacitors, and one charging inductor. In both proposed inverter topologies, the switched capacitors automatically balance to voltages of Vdc and 2Vdc. Additionally, the charging inductor helps reduce spike currents in the capacitor charging path. These inverters offer several advantages, including a reduced component count, low per-unit total standing voltage, high efficiency, increased power density due to fewer components, reduced spike currents, and a common ground (CG) structure that entirely eliminates leakage current. The proposed inverters employ a proportional-integral (PI) controller with phase disposition pulse-width modulation (for the first converter) and staircase modulation (for the second converter). A comparative analysis of existing and proposed five-level inverters is presented, demonstrating their suitability for grid-tied photovoltaic applications through MATLAB Simulink simulations and experimental validation using Hardware-in-the-Loop (HIL). © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025.
A roadmap to UV-protective natural resources: Classification, characteristics, and applications
(Royal Society of Chemistry, 2021) P, P.; Salian, A.; Dutta, S.; Mandal, S.
Alongside the innumerable benefits of solar rays, the adverse effects of ultraviolet (UV) radiation must be considered. All organisms are subjected to the deleterious effects of UV radiation, particularly UVA (315-400 nm) and UVB (280-315 nm). Continuous UV exposure leads to skin cancer, erythema, and sunburn mediated by reactive oxygen species (ROS). Photoprotection is hence an indispensable feature in all strata of the ecosystem across the microbial, plant, and animal kingdoms, especially under the present circumstance of increased ozone depletion. Photoprotective compounds, like gadusols, mycosporine-like amino acids (MAAs), scytonemin, phenolic compounds like flavonoids, anthocyanins, lignin, and less-explored compounds like sporopollenin, parietin, and usnic acid have been identified in various organisms. Accumulation of photoprotective pigments is a universal mechanism of passive protection against UV, developed by organisms during the early stages of their evolution. Furthermore, many of these compounds contribute to antioxidant and anti-inflammatory actions, which offer additional protection. In this review, the attributes of naturally available UV-screening compounds are investigated. Their taxonomic diversity, mechanism of UV absorption, extraction, and characterization techniques are discussed. In the wake of recent studies that indicate free radical generation in inorganic sunscreen compounds like TiO2 and ZnO, natural products have become a necessity. Insights into natural compounds for photoprotective functions in commercial applications like cosmetics and textiles are also reviewed. Biocompatibility and minimal side effects of these natural compounds open the gateway into an era of green products in the arena of photoprotection. © the Partner Organisations.
A Study on High-Frequency Transformer Design with Different Core Configurations for Flyback Converter Topology
(Institute of Electrical and Electronics Engineers Inc., 2023) Vignesh Kumar, V.V.; P, P.; Vangapally, A.; Balasubramanian, B.
The rapid advancements in the switched mode regulator technology necessitate an effective magnetic circuit for the converter topology. The design of magnetics plays a vital role in achieving the essential requirements of switching regulator circuits such as high-power density level, low thermal dissipation and high efficiency. Hence, this paper is focused on the high-frequency practical transformer design for flyback topology that is most widely used in the switched mode power supplies units. A case study is performed by employing different core configuration for high frequency flyback transformer which is the main contribution of this paper. The comparative performance analysis in terms of the dimensions, losses incurred and efficiency is reported for selecting the proper choice of core for the flyback topology. Â© 2023 IEEE.
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.
Configurations of modular push-pull buck DC-DC converters for 12KW telecom SMPS and its design
(Institute of Electrical and Electronics Engineers Inc., 2016) P, P.; Kalpana, R.
In this paper the push-pull buck DC-DC converter topologies are presented for 12kW telecom power supply. They have some attractive features compared to boost converters such as meeting the requirement of varying controllable output dc voltage, inherent short-circuit protection, and easy control of inrush current. Their input currents can be controlled in the open loop and much wider voltage loop bandwidth can be achieved. The proposed modular converter is modeled and its various configuration performance is simulated in MATLAB environment along with SIMULINK and Sim Power System (SPS). Â© 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 implementation of seven-level inverter for grid-tied photovoltaic systems
(Taylor and Francis Ltd., 2025) Maheswari, G.; Manjunatha Sharma, K.M.; P, P.
Multi-level inverters without transformer coupling are growingly popular for solar uses because of their compact design, minimised voltage stress, and improved efficiency. In this paper, the proposed novel triple-boost 7-level inverter is optimised for seamless integration with the grid. The proposed inverter employs self-regulating switched-capacitors to achieve a threefold voltage amplification, effectively eliminating the need for an independent boost converter stage. This architecture benefits low-voltage PV systems by improving efficiency, reducing cost, and ensuring superior performance. Moreover, the 7-level inverter adopts a common-ground topology, effectively mitigating leakage currents in PV system applications. The paper elaborates on the operational modes of the proposed inverter and the design of a current controller tailored for a grid-tied PV-based seven-level inverter. Additionally, simulation and experimental validation are conducted utilising hardware-in-the-loop (HIL) methods to evaluate system performance. Finally, a comprehensive comparative analysis is presented between the proposed seven-level inverter and existing seven-level inverters, highlighting the advantages of the proposed inverter design. © 2025 Informa UK Limited, trading as Taylor & Francis Group.
High performance front-end PFC rectifier for telecom power supplies
(Institute of Electrical and Electronics Engineers Inc., 2017) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.
High-current low-voltage (HCLV) rectifiers are used in the telecom industries, electroplating and induction heating system. Typical power rating of these rectifiers varies from tens of kW to hundreds of MW. In this paper, a three-phase three-level boost type PWM rectifier is proposed as an active front-end PFC scheme for telecom load. The proposed active front-end PFC converter is modeled by switching cycle average model and relation between duty ratio and the dc-link capacitor voltage is derived as in terms of system input currents. Also, the switching states have been derived for the feasible converter operation. The detailed analysis of front-end PFC converter is carried out by equivalent circuit. The power quality also well improved by proposed active front-end PFC rectifiers. The experimental setup for a 12 kW active front-end PFC rectifier is developed in the laboratory to validate the MATLAB simulation results. Â© 2016 IEEE.
High performance three-phase PFC rectifiers for telecom power supply
(Institute of Electrical and Electronics Engineers Inc., 2016) P, P.; Kalpana, R.
Generally telecom power supply requires higher efficiency from the ac input mains to the load end. So the front-end power factor correction (PFC) rectifier should show very high efficiency. In this paper, the front-end ac-dc converter having a boost type PFC rectifier which is a logical solution to the telecom applications is proposed. The Minnesota rectifier and Delta Switch rectifier are discussed for the front-end PFC converter which can be used for power quality improvement. Then the output of PFC rectifier is given to the three-phase high frequency dc-ac converter which intern drives the high frequency transformer (HFT) and produces the voltage level of 60V and 100A. These whole front-end and back-end converter configurations are classified as hybrid telecom power supply. The performance of front-end three-phase PFC rectifier with the back-end dc-dc converter configuration is simulated in the MATLAB Simulink environment and the results are presented in order to validate the design. Â© 2016 IEEE.
High Speed Data Compression Using FPGA
(Institute of Electrical and Electronics Engineers Inc., 2025) Dileep Kumar, M.J.; de Castro, G.A.; Anusha, R.; P, P.; Srinivas, B.
Efficient data compression is critical in modern digital systems to optimize storage and transmission bandwidth, especially in real-time applications. FieldProgrammable Gate Arrays (FPGAs) provide high-speed, hardware-accelerated solutions for data compression, offering parallel processing capabilities and reduced latency. This paper explores FPGA-based implementations of Run-Length Encoding (RLE) and Delta Encoding, two widely used lossless compression techniques. Performance is analyzed in terms of resource utilization, compression efficiency, power consumption, and scalability using the Xilinx Spartan-6 FPGA. Our results demonstrate that Delta Encoding achieves higher clock frequencies and lower power consumption, making it suitable for incremental data applications. In contrast, RLE excels in compressing redundant data sequences but has higher implementation complexity and variable throughput. The comparative study highlights the tradeoffs between these two methods and provides insights into their suitability for FPGA-based data compression in resourceconstrained environments. Â© 2025 IEEE.
High-efficiency improved 12kW switched mode telecom rectifier
(Institute of Electrical and Electronics Engineers Inc., 2016) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.
In this paper an improved switched mode telecom rectifier for a 12kW telecommunication system is presented. An improved telecom rectifier is a combination of phase-shift transformer based ac-dc converter and passive high pass filter. The phase-shift transformer and high pass filter is realized with a fractional magnetic rating of the load. The supply current is almost sinusoidal with low total harmonic distortion, and the power factor (PF) is close to unity. The complete design of phase-shift transformer based ac-dc converter and passive high pass filter is presented in this paper. The 12kW telecom rectifier is designed, modeled and simulated to reduce the total harmonic distortion (THD) of the input ac mains current and to improve the power factor. A laboratory prototype of phase-shift transformer based ac-dc converter is developed and the results are presented to validate the design topology. Â© 2015 IEEE.
Inclusive Design and Development of Front-End Multiphase Rectifier with Reduced Magnetic Rating and Improved Efficiency
(Institute of Electrical and Electronics Engineers Inc., 2020) P, P.; Kalpana, R.; Singh, B.
This article proposes a 20-pulse asymmetric multiphase converter (AMPC) suitable for medium-and high-power applications. Unlike the other state-of-the-art 20-pulse delta-connected autotransformers, the proposed delta-connected AMPC has an ability to reduce input harmonics, maintains high efficiency, and requires a magnetic rating of only 30.12% of the nominal load; thereby, a significant reduction in space, weight, and overall cost required is the salient features of the proposed AMPC. A detailed power quality performance analysis and an efficiency calculation are discussed. First, the proposed AMPC configuration is simulated in MATLAB/Simulink environment for evaluating its viability under different loading conditions, and the results are illustrated. A detailed comparison of the proposed AMPC configuration with other multipulse transformers is included, which confirms the merits of the proposed system. Also, a prototype is developed, and the experimental measurements obtained are presented to validate the feasibility and operability of the proposed AMPC. The proposed AMPC offers a total harmonic distortion of 3.7% and can operate at near-unity power factor complying with the IEEE and IEC standards. © 2013 IEEE.
Modified Current Control for Tracking Global Peak Under Fast Changing Partial Shading Conditions
(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Balasubramanian, B.; Ramana, V.
The power - voltage (P-V) characteristics of photovoltaic (PV) systems exhibit multiple power peaks under partially shaded conditions. Several global maximum power point tracking (GMPPT) algorithms in the literature recognize the irradiance change, only after the convergence of operating point to global peak, or use additional hardware to call GMPPT subroutine at definite time intervals to detect any insolation change, and thus track the global peak. However, during fast changing partial shading conditions, these methods are less effective, as they do not detect any irradiance change during the tracking phase of any shading pattern. This paper proposes a novel modified current control approach that uses current as a parameter to detect the insolation change during the tracking phase and track the global peak under fast changing partial shading conditions without any additional hardware. The proposed technique improves the tracking efficiency by as much as 39%, thus proving to be effective under fast-changing partial shading conditions. The superior tracking performance of the proposed algorithm over the existing techniques in terms of its tracking efficiency, dynamic tracking capability, tracking speed, and convergence to the global peak is demonstrated with extensive simulations using MATLAB/Simulink and experimental results. © 1986-2012 IEEE.
Power factor correction in multi-pulse rectifier using zigzag auto-connected transformer and non-isolated SEPIC converters
(Institute of Electrical and Electronics Engineers Inc., 2020) Nikshitha Rao, A.S.; Kalpana, R.; P, P.; Singh, B.
To enhance the harmonic mitigation capability of the multi-pulse rectifier, this paper proposes a multi-pulse rectifier based on harmonic mitigation technology at DC link. The conventional 12-pulse rectifier does not meet the IEEE-519 standard and hence the active power factor correction technique is employed to mitigate the harmonics. The proposed system employs two diode bridge rectifiers, each followed by a SEPIC converter, by controlling the SEPIC converter inductor current, the input line current of the rectifier can be approximated to a sinusoidal waveform. A zigzag connected autotransformer is used as a phase-shift transformer in order to provide a phase shift and inherently blocks the zero sequence components. This method reduces the total harmonic distortion and also decreases the size of the system. The proposed configuration is analyzed and simulated in the MATLAB Simulink and also implemented in laboratory. The results show that the proposed method improves the power quality by reducing the total harmonic distortion (THD) in the input line current. Â© 2020 IEEE.
Power Quality Enhancement Using Current Injection Technique in a Zigzag Configured Autotransformer-Based 12-Pulse Rectifier
(Institute of Electrical and Electronics Engineers Inc., 2018) Kalpana, R.; Chethana, K.S.; P, P.; Singh, B.
This paper proposes a DC-side circuit configuration that improves the harmonic suppression ability of a 12-pulse diode bridge rectifier (DBR) using a zigzag configured autotransformer. The DC-side circuit uses a single-phase DBR along with interphase transformer which generates the required circulating current thereby modifies the DC currents at the DBR output, in turn shapes the input line current near to a sine wave. The proposed single-phase DBR is connected in parallel with the load which enables to reuse the harmonic energy thus improving the energy conversion efficiency. The zigzag configured autotransformer used for 12-pulse DBR possesses the inbuilt ability to hinder the zero-sequence components, which expel the need of zero sequence blocking transformer. The proposed configuration is analyzed, simulated in MATLAB Simulink and the simulation results are presented, which confirm the reduction of total harmonic distortion (THD) in the input line current thereby improving the power quality under large load variations. Furthermore, the viability of the proposed configuration is verified by experimental results, which confirm the suitability of the proposed configuration in industrial applications. © 1972-2012 IEEE.