Browsing by Author "Manjunatha Sharma, K.M."

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A Novel Five-Level Double-Boost Inverter with Reduced Spike Current
(Institute of Electrical and Electronics Engineers Inc., 2024) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
This paper proposes a novel five-level double-boosting multi-level inverter (MLI) that uses a single DC source and requires only six power switches, one diode, and one capacitor. This design enables soft charging of the capacitor by integrating a charging inductor, which helps minimize or completely avoid large inrush or spike currents in the charging pathway. In this proposed topology, the capacitor is self-balanced. The proposed inverter topology offers several advantages compared to existing five-level inverters, such as significantly reducing inrush current, boosting capability, lower total standing voltage (TSV), common ground configuration, higher efficiency, and using fewer components. MATLAB Simulink simulations demonstrate the superior effectiveness of the proposed five-level double-boosting MLI in terms of reducing spike current. Â© 2024 IEEE.
A Novel PWM Technique for MPPT Tracking of PV-Based Cascaded H-bridge Multi-level Inverter
(Institute of Electrical and Electronics Engineers Inc., 2023) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
This paper presents a novel Pulse Width Modulation (PWM) technique designed for a Cascaded H-Bridge (CHB) grid-tied multilevel inverter used in Photovoltaic (PV) systems, featuring a single-stage power conversion. Each inverter's output voltage adopts a quasi-square waveform tailored to correspond with the power generated by the respective solar panel. A key highlight of this technique is its simplicity, avoiding complex implementation. By incorporating the proposed PWM technique into the cascaded H-Bridge inverters, it efficiently optimizes the Maximum Power Point Tracking (MPPT) for each PV panel, regardless of whether the irradiation conditions are uniform or non-uniform, while simultaneously achieving DC capacitor voltage balance. Moreover, employing this PWM technique simplifies the implementation process on a DSP, avoiding unnecessary complexity. Â© 2023 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 sorted modified multi-reference PWM technique for solar PV panel companion grid-tied inverters
(Springer Science and Business Media Deutschland GmbH, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
Pulse Width Modulation (PWM) techniques are increasingly vital in solar energy-driven grid-tied companion inverters, significantly enhancing power quality. This paper proposes the Sorted Modified Multireference Pulse Width Modulation (SMMR PWM) technique. The SMMR PWM with a Maximum PowerPoint Tracking (MPPT) control strategy is implemented in a Solar PV Panel Companion Grid-Tied Inverter (SPPCGTI) system featuring single-stage power conversion. In the SPPCGTI system, each inverter's output voltage adopts a quasi-square waveform, where the pulse width correlates with the power generated by the associated solar PV panel. By employing the SMMR PWM technique with the MPPT control strategy in the SPPCGTI system, precise MPPT for each PV panel is achieved, irrespective of uniform or non-uniform irradiation conditions. Additionally, this technique reduces Total Harmonic Distortion (THD) in the AC grid current of the solar PV panel companion inverter (SPPCI) while simultaneously enhancing MPPT efficiency, inverter efficiency [inverter efficiency is less than the Sorted-Staircase Modulation (SSCM) and more than the Sorted PWM (SoPWM)], and reducing settling time compared to the existing techniques like SSCM and SoPWM. The SPPCGTI with the integrated SMMR PWM technique, MPPT algorithm, and current controller is modeled and simulated in MATLAB/Simulink. Experimental testing affirms the outstanding performance of the proposed SMMR PWM technique. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
An improved control strategy without current sensors for DSTATCOM
(Inderscience Publishers, 2018) Saralaya, S.; Manjunatha Sharma, K.M.
An improved control strategy based on power balancing algorithm without using current sensors is presented in this paper. The mathematical model of this improved method is discussed. Point of common coupling (PCC) voltage and DC link voltage are taken as voltage commands for reference signal generation. Sinusoidal pulse width modulation is used to generate the pulses for distribution static compensator (DSTATCOM). Proportional integral (PI) controller is used to control the PCC voltage and DC link voltage of the voltage source converter of DSTATCOM. This improved method is tested for different load conditions using PSCAD/EMTDC package. The improved control strategy is validated by simulation results for linear and non-linear load conditions. © © 2018 Inderscience Enterprises Ltd.
Coordinated bidirectional power flow management with power quality improvement in AC-DC hybrid micro-grid under unbalanced Scenario
(Islamic Azad University ijes@mshdiau.ac.ir, 2019) Nagaraj, C.; Manjunatha Sharma, K.M.
The present day electrical power system is highly complex due to the increase in load demand and distributed generations. Further, the intermittent renewable sources and non-linear power electronic loads connected to the grid deteriorates the power quality of the system. Also, the more and more DC loads like LED lights to save energy consumption are connected to the AC distribution system. These issues can be effectively addressed using the smart micro-grid system. In an individual AC or DC micro-grid, the higher number of AC-DC-AC/DC-AC-DC power conversion stages lead to the increased power losses. Therefore, in this paper, an AC-DC hybrid micro-grid topology is proposed, wherein, AC sources and AC loads are connected to AC grid while DC sources and DC loads are connected to DC grid there by reducing the power conversion losses. The shunt active power filter based 3-phase 4-leg bidirectional interlinking converter using d-q reference current method with PI control is proposed to accomplish the inverter-based & rectifier-based power exchange between AC & DC sub-grids with harmonic current compensation under various grid and load conditions. The analysis is carried out in MATLAB/SIMULINK and results proving the improved power quality. © 2007-2017 Majlesi Branch, Islamic Azad University.
Design and Development of an Emulator for Distribution Automation Using DCS
(Institute of Electrical and Electronics Engineers Inc., 2018) Hanumantha Rao, B.; Chandan Kumar, B.; Manjunatha Sharma, K.M.; Selvan, M.P.
The distribution system in the power system network plays vibrant role in the delivery of electrical energy to the consumers. Automation in the field of distribution system empowers more flexible control for the utilities, which is effectively used to enhance the efficiency, power quality and reliability of electrical supply services. Presently, the advanced developments in the information and communication technologies and intelligent electronic devices make the distribution network operations more resilient, efficient, reliable and cost effective. This paper presents brief overview about the design and development of distribution system automation. This involves design of distribution substation model and provision of automation for it. Automation involves isolation of fault and restoration of the service, when a fault occurs in any one of the feeder. Load transfer between the feeders, between incomer and load scheduling, display of energy consumption of each feeder are a few functions of automation. Â© 2018 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.
Implementation of a novel nine-level double boosting multi-level inverter
(Springer Science and Business Media Deutschland GmbH, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
Switched capacitor multi-level inverter topologies have garnered the attention of industrial power electronics researchers due to their potential in different industrial and renewable energy source applications. This paper proposes a novel nine-level, twofold voltage gain boost (9L2x) inverter designed for photovoltaic (PV) applications, addressing common challenges in transformer-less multi-level grid-tied PV inverters, such as leakage current and output voltage bucking. This design utilizes switched capacitors (SC) with a common ground, achieving a twofold voltage boost without needing an extra boost converter. The proposed topology reduces the active switch count, enhances power density, and lowers costs while ensuring self-balancing SCs and minimizing total standing voltage. The common grounding mitigates leakage current, making the system more efficient. The proposed topology features a diode-inductor circuit at the input DC side to reduce inrush current, decrease capacitor voltage ripples, reduce the total harmonic distortion of the MLI output voltage, and improve efficiency. A proportional-integral controller manages active grid power, and a modulation strategy ensures SC voltage balance. The paper delves into intricate details concerning the inverter’s circuitry, control methodologies, and pulse-width modulation scheme. This nine-level inverter design is thoroughly validated through extensive simulations and practical hardware-in-the-loop experiments. The results consistently affirm the effectiveness and feasibility of this novel inverter, positioning it as a significant advancement over existing nine-level inverters. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Implementation of a Novel Nine-Level Quadruple Boosting Inverter
(Institute of Electrical and Electronics Engineers Inc., 2024) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
This paper proposes a novel nine-level quadruple-boosting multilevel inverter (MLI) that uses a single DC source and requires only ten power switches, one diode, and three capacitors. This design utilizes switched capacitors (SC) with a common ground (CG), achieving a four-fold voltage boost without needing an extra boost converter. The common grounding mitigates leakage current, making the system more efficient. In this proposed topology, the capacitors are self-balanced. The proposed inverter topology offers several advantages compared to existing nine-level inverters, such as significantly reducing leakage current due to common ground configuration, boosting capability, and using fewer components. MATLAB Simulink simulations demonstrate the superior effectiveness of the proposed nine-level quadruple-boosting MLI. Â© 2024 IEEE.
Implementation of a Novel Quadruple-Boost Nine-Level Inverter for Grid-Tied Applications
(Springer Nature, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
This paper proposes a novel transformer-less quadruple-boost nine-level (QBNL) inverter specifically developed for grid-tied applications. Traditional multilevel inverters (MLIs) typically require numerous components and a transformer for grid integration, which increases cost, weight, size, and losses, thereby diminishing overall efficiency. The proposed nine-level quadruple-boost inverter overcomes these challenges by providing a more streamlined design, significantly enhancing system performance and efficiency. The topology of the proposed inverter consists of ten switches, one diode, and three switched capacitors. These capacitors are self-balanced, maintaining voltage levels at Vdc, 2Vdc, and 2Vdc relative to the input voltage. With a reduced component count (10), lower total standing voltage per unit (5.75), lower cost factor, improved efficiency (97.73), and higher power density, this design offers significant advantages over existing nine-level inverters. The proposed inverter has a soft charging circuit at the DC side to reduce the impulse currents, and a common-mode choke is inserted between the inverter output and the grid to reduce leakage current in PV applications. Additionally, the proposed system incorporates a proportional-integral (PI) controller and phase disposition pulse width modulation technique. A comparative analysis between the proposed nine-level quadruple-boost inverter and existing nine-level inverters highlights its superior performance. The effectiveness of the proposed quadruple-boost nine-level inverter is verified through MATLAB Simulink simulations and Experimental Hardware-in-the-Loop (EHIL) testing, confirming its suitability for grid-tied applications. © 2017 Elsevier Inc. All rights reserved. © The Author(s), under exclusive licence to Shiraz University 2025.
Implementation of Sorted Stair-Case Modulation and Sorted Phase Disposition PWM for Grid-Tied Multi-Level Inverter
(Institute of Electrical and Electronics Engineers Inc., 2023) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
Integrating a multilevel inverter with the grid provides advantages in high-power and high-voltage applications, including reduced harmonic distortion without a transformer. This paper presents the implementation of Sorted stair-case modulation (SSCM) and Sorted Phase disposition (SPD) Pulse Width Modulation (PWM) techniques for a Grid-Tied Cascaded H-Bridge (CHB) multilevel inverter featuring single-stage power conversion. SSCM and SPD PWM techniques are used to track the MPPT of each PV panel under uniform and non-uniform irradiation conditions if the PV panels are connected to the inverter's input terminals. A centralized current controller has been designed for the Grid-tied multilevel inverter system. Furthermore, a simulation has been developed to compare the power quality of the grid current and voltage between SSCM and SPD-PWM. Â© 2023 IEEE.
Improvement of harmonic current compensation for grid integrated PV and wind hybrid renewable energy system
(Institute of Electrical and Electronics Engineers Inc., 2016) Nagaraj, C.; Manjunatha Sharma, K.M.
Ideally, electric utilities are required to supply sinusoidal voltage at constant rated frequency while end users need to receive a sinusoidal current with good power factor. Electrical power distribution systems are already experiencing distortion of the current due to the usage of non-linear power electronic loads in industrial and commercial applications. Further, the integration of intermittent hybrid renewable sources like solar and wind to the utility grid through 4-leg 3-phase 4-wire current controlled voltage source inverter (VSI) leads to cause still more current distortion which pollutes the quality of electric power at the end users. Thus power quality is a critical issue to be addressed effectively. The active power filter (APF) is advantageous over passive filter due to its capability for better harmonic compensation features. This paper presents analysis of shunt active filter (SHAF) using a PI controller with and without the incorporation of intermittent hybrid renewable sources under different grid conditions. An instantaneous real and reactive current (id-iq) control scheme for SHAF is proposed for reduction in harmonic levels. The MATLAB/Simulink simulation studies validates the performance of id-iq control method. Â© 2016 IEEE.
Integration of hybrid solar-wind energy sources with utility grid for improving power quality
(Institute of Electrical and Electronics Engineers Inc., 2018) Nagaraj, C.; Manjunatha Sharma, K.M.
Most of the utilities are suffering to provide continues and clean power at the end users due to grid current distortion in the distribution system because of non-linear low power electronics loads. In addition to this, freely available inherent hybrid solar-wind energy sources are leads to cause some more grid current distortion. Adverting to the above major issue over long decade, this paper presents an efficient controller for 3-phase 4-leg interfacing voltage source inverter to perform not only current harmonic reduction but also optimal real power transfer, neutral current compensation and power factor correction simultaneously. These multiple functions can be achieved efficiently by using id-iq control based shunt active power filter. The hysteresis comparator control is used to compare the obtained reference currents from id-iq control with actual sensed actual currents to generate the error signal. This error signal decides the working of the inverter switches. The simulation is carried out by using MATLAB/SIMULINK tool under different grid and load conditions and the corresponding simulated results are encouraged. Â© 2018 IEEE.
Investigation of performance of DSTATCOM with improved current sensorless controller
(Institute of Electrical and Electronics Engineers Inc., 2018) Saralaya, S.; Manjunatha Sharma, K.M.
The performance analysis of Distribution static compensator with a modified current sensorless controller which is designed for unbalanced load condition is presented in this paper. The investigation of the controller is performed with the presence of voltage sag and swell. To control terminal voltage and dc link, the proportional integral controller is used. The DSTATCOM is placed in IEEE 13 industrial system. The analysis is done in PSCAD/EMTDC package. Â© 2018 IEEE.
Novel sorted PWM strategy and control for photovoltaic-based grid-connected cascaded H-bridge inverters
(Springer, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; Prabhakaran, P.
This paper proposes a novel sorted level-shifted U-shaped carrier-based pulse width modulation (SLSUC PWM) strategy combined with an input power control approach for a 13-level cascaded H-bridge multi-level inverter designed for grid connection, specifically tailored for photovoltaic (PV) systems, which avoids a double-stage power conversion configuration. In this methodology, every inverter generates a quasi-square output voltage waveform with a width that is intricately linked to the output power of its corresponding PV panel. The application of this SLSUC pulse width modulation technique with input power control in a solar energy-based 13-level grid-tied inverter facilitates precise maximum power point (MPP) tracking for each of the PV panels under uniform and non-uniform irradiation conditions and ensures the consistent maintenance of capacitor voltage balance. Moreover, this novel SLSUC PWM method for 13-level inverters offers a range of benefits, including a low total harmonic distortion (THD) in the output voltage of the multi-level inverter and higher inverter and MPPT efficiencies over the existing PWM techniques. To verify the efficacy of the proposed control method over existing techniques, a PV-based grid-connected multi-level inverter with the proposed control strategy undergoes modeling and simulation using MATLAB/Simulink. Then, experimental hardware-in-the-loop (EHIL) testing is conducted to confirm and evaluate its effectiveness. © The Author(s) under exclusive licence to The Korean Institute of Power Electronics 2024.
Passive Islanding Detection Scheme Based on Instantaneous Voltage and Current for a Multi-DG Microgrid
(Institute of Electrical and Electronics Engineers Inc., 2024) Pinto, J.A.; Vittal, K.P.; Manjunatha Sharma, K.M.
The electricity grid has been transforming since its inception. The increase in carbon emissions and scarcity of fossil fuels has led to using renewable energy sources for power generation. In recent times, microgrids have been gaining popularity, as they can connect to the grid or disconnect from the grid to supply power to the local loads during grid failure and calamities. The presence or absence of the utility grid is crucial to the overall operation of the microgrid. This paper focuses on early islanding detection by considering the instantaneous values of phase voltage and line currents. In the proposed method, the relative position of voltage and current signals are monitored, and a coincidence index keeps track of any change in their relative positions. During the grid-connected operation, the coincidence index remains low. However, when the grid is disconnected, the coincidence index rises. Islanding is detected when the coincidence index crosses a fixed threshold. MATLAB/Simulink-based simulation studies were carried out on the IEEE 13 bus system to check the effectiveness of the proposed Instantaneous Islanding Detection technique during normal operation, faults, switching of loads, and switching of Distributed Generators. It was found that the proposed scheme could detect islanding in less than one-fourth of the cycle and has a low non-detection zone. Also, during the evaluation, the proposed instantaneous islanding detection technique identified islanding much earlier than existing methods. © 2024 The Authors.
Performance analysis of automated quantitative feedback theory based robust controller for photovoltaic converter
(Institute of Electrical and Electronics Engineers Inc., 2018) Gudimindla, H.; Manjunatha Sharma, K.M.
Robust controller design for photovoltaicconverters (PVC) has received considerable critical attention due to solar panels operated under uncertain environmental circumstances. This paper presents automated loop-shaping based robust controller design for PVC voltage regulation with the aid of quantitative feedback theory (QFT) using Genetic algorithm. The step by step design guidelines for the automated QFT (AQFT) robust controller is deliberated in detail. The proposed AQFT controller exhibits decreasing modular plot, descending phase response and nearer to the universal bound to replicate the controller ideal characteristics. Finally, benchmarking of the proposed controller with affine parameterization design method available in the literature is performed through simulations. Â© 2018 IEEE.
Performance analysis of robust and nonlinear MPPT controllers for autonomous wind power system
(Institute of Electrical and Electronics Engineers Inc., 2017) Gudimindla, G.; Manjunatha Sharma, K.M.
This paper presents the performance analysis of nonlinear and robust control strategies for the maximum power extraction from permanent magnet synchronous generator (PMSG) based autonomous wind energy conversion system (WECS) under varying wind speed. The Nonlinear control strategy aims to achieve improvement in speed tracking performance by using feedback linearization method used to select the optimal control input by compensating nonlinearities in the WECS directly driven by PMSG. In order to design the Robust Quantitative Feedback Theory (QFT) based controller and multi model QFT controller for the WECS based on PMSG, the nonlinear system is represented by a series of linear time invariant transfer functions around different operating points. Robust controllers are designed for proper selection of optimal control input to extract maximum power for every wind speed. Performance analysis is done from the MATLAB simulation results among the controllers for the PMSG based WECS. Multi model QFT controller is recommended for their enhanced performance. Â© 2016 IEEE.