An Advanced Modular Multilevel Inverters for 
Grid-connected PV Optimization by Maximum Power Point Tracking

Tata Rao Donepudi; Kondala Rao Parasa; Bhimaraju Pemmanaboidi Srihari Datta; Uma Phanendra Kumar Chaturvedula; Anupalli Immanuel

doi:doi:10.11648/j.sdenergy.20260101.11

Research Article |

| Peer-Reviewed

An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking

Tata Rao Donepudi^*

, Kondala Rao Parasa

, Bhimaraju Pemmanaboidi Srihari Datta

, Uma Phanendra Kumar Chaturvedula

, Anupalli Immanuel

Published in Science Discovery Energy (Volume 1, Issue 1)

Received: 12 October 2025 Accepted: 29 January 2026 Published: 25 February 2026

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Abstract

Modular multilevel inverters (MMLIs), acknowledged not only for its modular structure, scalability and low harmonic distortion but also offers an efficient solution_, for managing high-power renewable-energy applications. However, these often depends on conventional centralized control methods_, which are insufficient in addressing critical challenges like scalability and hardware delays in distributed control systems. This paper emphases on the design and implementationof an advanced 3-Ph. MMLI for a 400-kW solar plant connected to a 25 kV grid. The study examines the system's performance, control strategies and operational challenges encountered during the integration with grid. To optimize energy extraction from the PV array, incorporate a DC/DC_, converter featuring MPPT_, through ‘Perturb and Observe’ (P & D) technique. The extracted energy is then stepped up and converted into 3-Ph. AC voltage through MMLI. The output from these, feed into a common 500V DC bus, enabling the overall system integration. Unlike earlier methods which are used open-loop control to address power imbalances among legs, this study employs closed-loop control using to correct mismatched DC loop currents. This allows, dynamic adjustment the voltage across PV array to optimize output efficiency. The efficacy of the proposed control-strategy has been validated through Mat lab/Simulink simulations, demonstrating its potential.

Published in	Science Discovery Energy (Volume 1, Issue 1)
DOI	10.11648/j.sdenergy.20260101.11
Page(s)	1-13
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2026. Published by Science Publishing Group

Keywords

Modular Multilevel Inverter (MMLI), Voltage Sourced Converter (VSC), Distributed Maximum Power Point Tracking (DMPPT), Total Harmonic Distortion (THD).

1. Introduction

The increasing global demand for electricity is accelerating the fossil-fuels depletion and the rise in emissions of greenhouse-gasses. To combat these issues, many nations are taking significant steps toward the widespread adoption of renewable energy sources like wind, solar, biomass, tidal, and hydropower. These renewable technologies are pivotal in generating clean energy and reducing greenhouse gas emissions thus fostering sustainable development. By 2016, researchers recorded a deployment of 921 GW of renewable energy (excluding hydropower), highlighting the growing awareness of climate change and the urgency of transitioning to green energy. To eliminating the need for transmission near the loads systems by integrating renewable energy

[1]

sources and conventional power systems through distribution networks referred to as distributed generation. However, this system disorder the unidirectional power flow pattern of traditional distribution networks and lead to challenges like bidirectional power flow. This can negatively be impact the network’s performance. It leads to issues like reduced power quality, desensitized relays, increased fault currents and compromised reliability at significant portions of the distribution grid. Micro grids (MGs) are utilized as platforms for integrating distributed generation systems to discourse these issues. Micro-grids provide substantial benefits to both distribution networks and end-users by minimizing disruptions. Among renewable sources like solar, wind and tidal-energy, PV systems are recognized as one of the most effectual and adaptable energy source. This source effectively serving both small and large-scale power generation needs. There are different types of grids, such as AC, DC, hybrid AC/DC and multi-micro grids (MMGs). These systems integrate assorted methods for power conversion, storage, distribution and utilization. To address energy management challenges effectively, this integration aids to make specialized comprehensive system-level models and component-level models

[2]

. Many of the design and operational principles from conventional power systems can be seamlessly applied to AC micro grids. The common DC-link voltage serves as a communication medium, ensuring effective power sharing between Energy Storage Systems (ESSs) and Distributed Generators (DGs) in DC micro-grids. In this MG, bus voltage is divided into several tolerance regions to assign priority levels to all converter units. Each converter's operation is dictated by the thresholds of these voltage regions. For instance, while the battery converter switches to maximum charging mode, if the DC-link voltage exceeds its rated value, the PV converter

[3]

will regulate the DC bus, during periods of high solar radiation. In the case of two-level inverters transfer maximum PV power effectively to the grid by maintaining UPF, there will be a few limitations such as power loss due to elevated switching-frequencies, high THD and voltage stress on switches

[4]

. On the other hand MLIs offer notable benefits, includes reduced THD, lowering switching-frequency, minimizing dv/dt and decreasing voltage stress on the switching components MLI technology employs a full-bridge inverter integrated with ancillary circuits to generate multiple output voltage levels

[5]

. This design improves grid-current quality and decreases the size of required filters. However, there will be some challenges, such as high switching frequencies, which contribute to voltage stress and limit switch lifespan. To address these issues, diode-clamped MLIs have attempted by incorporating more than 3-voltage levels for PV grid-integration

[6]

. Still, these designs often disrupt the principle of minimizing switching losses leads to increased harmonic distortion, elevated switching losses and higher voltage stress. Subsequently, they are less suitable for medium and low-voltage applications and demand larger AC filters for harmonic compliance

[7]

. Another configuration, called cascaded MLIs employed in PV systems, leveraging separate DC voltage sources. However, due to variable weather conditions, their performance can be affected by fluctuating PV input voltage, making it challenging to consistently maintain deliberate voltage levels. Two-stage grid connected PV system often requires boost converter for each unit to isolate DC inputs which increase system complexity and cost

[8]

. To overcome the limitations in these conventional topologies, modular multilevel inverters (MMLIs) have emerged as an innovative alternative. MMLIs effectively address drawbacks like, dependency on output filters and transformers, capacitor voltage imbalance at higher-levels and the inability to manage faults. Unlike traditional MLIs, MMLIs provide enhanced fault tolerance and reliability

[9]

. Their potential in PV systems remains underexplored, although MMLIs have been applied in various applications. This study focuses on developing a PV system with two transfiguration stages, a DC/DC converter to boost PV out-put voltage & MPPT and another for grid integration

[10]

. MMLI ensures the boost converter output voltage remains stable while injecting current into the grid with UPF. MMLIs are flexible and scalable power conversion systems. These are predominantly valued for producing output voltages with exceptionally low harmonic distortion, making them well-suited for high-voltage, high-power applications

[11]

. MMLIs are composed of two arms an upper and a lower arm. These both arms comprising multiple sub-modules connected in series. Each sub-module of the arm functions as a half-bridge circuit equipped with a parallel diode, enabling effective current regulation

[12]

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Figure 1. Topology of 1-Phase MMC with PV-modules embedded in each sub-module.

To handle fault currents resulting from voltage discrepancies between the arms, inductors and resistors are incorporated into both arms. Additionally, sub module capacitors are selectively activated and bypassed based on the operational requirements. Inductors (L_d) and resistors (R_d) within the arms work together to address voltage imbalances during the switching activities of the sub modules

[13]

. The operation of MMLI involves three primary states:

1) Blocking State: In this state, the sub modules remain non-functional, with one of the diodes conducting. The capacitor can either be engaged or bypassed.

2) Cut-in State: Here, Submodule-1 becomes operational, regardless of diode activity, leading to capacitor engagement.

3) Cut-off State: Submodule-2 is activated, overriding diode function, which results in the capacitor being bypassed.

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Figure 2. Schematic of 3-pase MMLI topology.

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Figure 3. Sub model of MMLI.

A sub-module (SM) is essentially a simplified chopper circuit, comprising two insulated-gate bipolar transistors (IGBTs) with switches-(S1 & S2) anti-parallel diodes (D1 & D2) and a capacitor (C). The out-put voltage (VSM) of a sub-module can take two values: when VSM = Vc, when S1 is activated, and S2 is off and VSM = 0, when S1 is off, and S2 is activated. Because of the following advantages of MMLI

[14]

are preferred for HVDC configurations over other topologies. Cascaded H-Bridge Converters (CHBs) have a simpler architecture, consisting of multiple H-bridge circuits connected in series, each powered by a separate DC source. While CHBs [15] boast advantages like easier control mechanisms and lower costs, they fall short in scenarios requiring high voltage and high power

[16]

. MMLI outperform CHBs in efficiency fault tolerance, and overall capability, making them the superior choice for demanding applications

[17]

Under steady state operation,

\frac{V}{2} - V_{u} (t) - L \frac{diu}{dt} = V_{A 0} (t) = V_{m} \sin (ωt)

(1)

By neglecting inductor drop,

\frac{V}{2} - V_{u} (t) = V_{A 0} (t) = V_{m} \sin (ωt)

(2)

Thatmeans,

V_{u} (t) = \frac{V}{2} - V_{m} \sin (ωt)

(3)

Similarly

\frac{V}{2} + V_{L} (t) - L \frac{diL}{dt} = V_{A 0} (t) = {- V}_{m} \sin (ωt)

(4)

This means,

V_{L} (t) = \frac{V}{2} {+ V}_{m} \sin (ωt)

(5)

Equations (3) and (5) above gives the converter voltages for upper arm for lower arm respectively.

If, Vm \leq \frac{V}{2} t h en 0 \leq V_{u} \leq V

Similarly,

0 \leq V_{L} \leq V

Hence, the total DC-link voltage is the sum of the voltages of both upper and lower arms.

It is important to consider that, the voltage rating of each cell and capacitor, which is expressed as E/N. with N representing the number of sub-modules in each arm

[18]

. The energy stores in the capacitor is similarly affected by the number of sub modules, highlighting the interconnection of these components. Additionally, it is observed that the voltage ratings for switches and capacitors tend to increase when the value of N is low. In terms of arm current both DC and AC components are present

[19]

. When temporarily disregard the capacitor voltage ripple, it can be note that half of the load current is channeled through the arms at the fundamental frequency. To ensure a balanced power flow, it is necessary for the arm current to include a DC component

[20]

. However, because of the single-phase nature of the power flow, a second harmonic voltage ripple manifests in the capacitor voltage, which can complicate the overall dynamics. This second harmonic voltage ripple also appears in the arms themselves

[21]

. In summary, while these factors introduce layers of complexity, they are all essential elements in maintaining power balance

[22]

. Addressing these complexities with a comprehensive approach will enable to foster a more stable and efficient system.

At steady state, the arm currents are:

i_{u} (t) = \frac{1}{2} i_{load} + \frac{1}{2} i_{cir} (t)

(6)

i_{l} (t) = \frac{1}{2} i_{load} - \frac{1}{2} i_{cir} (t)

(7)

i_{Load} (t) = i_{m} \sin (ωt - ϕ)

(8)

Where

i_{cir} (t)

is circulating current, has dc component and higher harmonics.

Arm energy balance at the steady state,

w_{u} (t) = \frac{V}{2} \frac{1}{2} i_{m} \sin (ωt) + \frac{V}{2} i_{cir} (t) - m \frac{V}{2} \frac{1}{2} i_{m} \sin (ωt) i_{m} \sin (ωt - ϕ) - m \frac{V}{2} \sin (ωt) i_{cir} (t) \sin (ωt) i_{m} \sin (ωt - ϕ)

(9)

Thus,

w_{u} (t) = \frac{V}{2} i_{cir} (t) + \frac{mV i_{m}}{8} \cos ϕ + \frac{V i_{m}}{4} \sin (ωt - ϕ) - \frac{mV}{2} i_{cir} (t) \sin (ωt)

- \frac{mV i_{m}}{8} \cos (2 ωt - ϕ)

(10)

Where

m = \frac{V_{m}}{\frac{V}{2}}

Where

V_{u} (t) = Voltage across upper arm

V_{A 0} (t) = No load voltage

V_{m} = Maximum voltage

V_{L} (t) = Voltage across lower arm

L = Inductor

i_{load} = Load current

i_{l} (t) = Load current

i_{m} = Maximum current

i_{cir} (t) = Circulating current

i_{dc} = DC current

Instantaneous power contains both AC and DC components, then it can be written as

w_{u} (t) = w_{u dc} (t) + w_{u ac} (t)

(11)

w_{u dc} (t) = \frac{V}{2} i_{cir} (t) - \frac{mV i_{m}}{8} \cos ϕ

(12)

w_{u ac} (t) = \frac{V}{4} \sin (ωt - ϕ) - \frac{mV}{2} i_{cir} (t) \sin (ωt) - \frac{mV i_{m}}{8} \cos (2 ωt - ϕ)

(13)

To ensure the arm balance at the steady state, average DC-power of lower-arm must be equal, zero. i.e.

w_{u dc} (t) = 0

It gives the circulating current,

i_{cir} (t) = \frac{1}{4} {mi}_{m} \cos (ϕ)

(14)

Let, i_dc be the current drawn from the DC-source then, Vi_dc is the drawn power (power-flows) from (into) the DC side.

Under the no-loss conditions of the converter, it would be equal to AC-power. Hence,

V i_{dc} = 3 \frac{Vm}{\sqrt{2}} \frac{i_{m}}{\sqrt{2}} \cos (ϕ)

(15)

i_{dc} = \frac{3}{4} m i_{m} \cos (ϕ)

(16)

w_{u} (t) = \frac{V}{2} i_{cir} (t) + \frac{mV i_{m}}{8} \cos ϕ + \frac{V i_{m}}{4} \sin (ωt - ϕ) - \frac{mV}{2} i_{cir} (t) \sin (ωt) - \frac{mV i_{m}}{8} \cos (2 ωt - ϕ)

(17)

By substituting the value of c1, in the above equation (17), then the upper arm energy is given by

IIB

w_{u} (t) = w_{uo} + \frac{V i_{m}}{4 ω} \cos (ϕ) - \frac{m {Vi}_{dc}}{6 ω} + \frac{m {Vi}_{m}}{16 ω} \sin (ϕ) - \frac{V i_{m}}{4 ω} \cos (ωt - ϕ) + \frac{mV i_{dc}}{6 ω} \cos (ωt) + \frac{m {Vi}_{m}}{16 ω} \sin (2 ωt - ϕ)

(18)

Similarly, the lower-arm energy is given by

w (t) = w_{lo} + \frac{V i_{m}}{4 ω} \cos (ϕ) - \frac{m {Vi}_{dc}}{6 ω} - \frac{mV i_{m}}{16 ω} \sin (ϕ) - \frac{V i_{m}}{4 ω} \cos (ωt - ϕ) + \frac{mV i_{dc}}{6 ω} \cos (ωt)

- \frac{m i_{m}}{16 ω} \sin (2 ωt - ϕ)

(19)

Where

w_{u} (t) = Upper arm power

w_{u dc} (t) = DC component of upper arm power

w_{u ac} (t) = AC component of upper arm power

w_{l} (t) = Lower arm power

\cos (ϕ) = Power factor

2. Mat Lab/Simulink Model of Proposed MMLI Topology

The below Figure. 4 depicts the schematic of Mat lab/Simulink model of a 400-KW Solar-Power Plant connected to a 25-kV grid using 3-Phase Modular Multi-Level Inverter.

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Figure 4. Mat lab/Simulink model of a 400-KW Solar-Power Plant connected to a 25-kV grid using 3-Phase Modular Multi-Level Inverter.

The below Figures. 5 & Figure. 6 represents the solar firm and its equivalent circuit. This solar farm comprises four photovoltaic (PV) arrays, each capable of delivering a peak output of 100 kW under optimal solar irradiance conditions of 1000 W/m². Each PV array block contains 64 parallel-strings, with every string comprising five Sun Power SPR-315E - module connected in series. These arrays are linked to individual DC/DC boost converters, modeled as average systems, which feed power into a centralized 500 V DC bus. Each boost converter is thoughtfully managed by a dedicated MPPT (Musong L 2023) which employs the P & D algorithm to effectively optimize the voltage across the terminals of the PV-array, ensuring maximum power extraction. The resulting DC output is then converted into a 260 V AC supply through a 3-phase VSC. While harmonic details are omitted, the model retains the dynamic behaviors critical for studying the interactions between control systems and the power grid. This abstraction allows for larger time steps (50 µs) during simulations, significantly enhancing computational efficiency without sacrificing the accuracy of system dynamics. The corresponding output voltage and current waveform of a DC-DC boost-converter are mentioned in the Figure 7.

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Figure 5. Mat lab/Simulink model of 400 KW solar farm.

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Figure 6. Mat lab/ Simulink model of Equivalent circuit model of 400 KW solar farm.

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Figure 7. Out-put Voltage and Current of DC/DC boost converter from PV array DC-DC boost-converter.

The below Figure 9 illustrates the Mat lab/Simulink model of a 3-Phase MMLI. In this design, each phase consists of two arms, upper and lower arm which is composed of several series- connected power sub modules. These sub-modules enable accurate voltage control and contribute to the high efficiency of the inverter. This architecture is especially beneficial in high power applications, viz. renewable energy integration, industrial motor-drives and HVDC-transmission systems.

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Figure 8. Schematic of Three-Phase MMLI.

Figure 9 and Figure 10 illustrate the out-put voltage from the upper and lower portion of a proposed MMLI. This output resembles to the voltage generated by the both arms of each phase. The voltage results from the coordinated operation of the sub-modules within each arm and reflects the applied control strategy. This output voltage exhibits the characteristic staircase waveform of MMLIs, a result of the sequential switching of the sub modules. Together, voltages from the upper and lower arms are integral in creating the total phase voltage mentioned in Figure 11, playing a critical role in the overall performance and functionality of the converter.

3. Inputs and Experimental Results

A 100 KW PV array is linked to a 25 KV grid-through a DC-DC boost converter and a 3-phase, 3-Level VSC. The boost converter employs MPPT using ‘Incremental Conductance + Integral Regulator’ method within a Simulink model. An alternative setup (PV Array Grid Average Model) employs averaged models for both DC-DC and VSC-Converters. In this configuration, MPPT controller follows ‘Perturb and Observe’ approach. The detailed parameter specifications are given in below Table 1 and Table 2 gives the features of PV Array Block.

Table 1. System Components and their specifications.

Parameter	Specifications
PV Array	Capable of delivering up to 100 kW under peak irradiance conditions (1000 W/m²).
DC/DC Boost Converter	Operating at 5 kHz, it elevates PV’s natural voltage (273 V DC at peak power) to 500 V DC. The MPPT controller dynamically adjusts duty-cycle to optimize voltage for maximum power extraction.
Filtering System	10 KVAR Capacitor-bank diminishes the harmonics generated by VSC
Coupling Transformer	100 KVA, 260 V/25 KV, 3-Ph. transformer connects the system to utility grid
Grid Infrastructure	Includes a 25 KV distribution-feeder & an equivalent 120 KV transmission network
PV Module Configuration	The system integrates 330 Sun-Power SPR-305E-WHT-D modules arranged in 66 strings each string containing five modules connected in series (66 × 5 × 305.2 W = 100.7 KW)

Table 2. PV Array Block features.

Parameter	Specifications
No. of series-connected cells	96
OC voltage (Voc)	64.2 V
SC current (Isc)	5.96 A
Max. power point voltage (Vmpt)	54.7 V
Max. power point voltage and current (Impt)	5.58 A

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Figure 9. Output voltage of upper part of converter.

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Figure 10. Output voltage of lower part of converter.

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Figure 11. Output voltage of 3-Phase MMLI.

The below Figure 12 illustrates the sinusoidal voltage and current waveforms at the utility grid interface, which are essential for evaluating system efficiency and power quality. A properly functioning grid ensures stable amplitude and synchronized phase relationships between the voltage and current, promoting reliable operation of connected systems and devices. These features are particularly significant in renewable energy applications, such as photovoltaic systems and modular multilevel inverters (MMLI). Any irregularities, such as phase shifts or harmonic distortions, can lead to operational inefficiencies and reduced power reliability. The depicted figure highlights the steady performance of the utility grid, made possible by the implementation of the proposed converter. The below Figure 13 depicts FFT (Fast Fourier Transform) analysis of the sub module's output voltage reveals a THD of 1.31% from 2.87% (comparison with conventional methods). This exceptionally low THD indicates that the voltage signal exhibits very minimal harmonic distortion, making it ideal for applications demanding clean and stable power output.

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Figure 12. Utility grid Output voltage and current.

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Figure 13. FFT window for output voltage.

4. Conclusion

This study introduced an advanced three-phase MMI tailored for grid-connected photovoltaic (PV) systems, effective emphasizing reliability and efficiency. This modular topology making it an appropriate solution for large-scale renewable energy-applications by reduces harmonic distortion, strengthens the fault tolerance and enhances flexibility. The integration of MPPT ensures optimal energy extraction in spite of fluctuating environmental conditions. Extensive simulations and experimental analysis confirm the inverter’s effectiveness in the grid stability, voltage regulation and improving power conversion. Also, this three-phase configuration ensuring seamless interaction with the electrical grid and enhances reliable synchronization. These conclusions highlight the potential of the proposed design to drive sustainable and high-performance solar energy solutions. This study also offering a solid foundation for future research and the practical implementation in renewable-energy technologies. Under fluctuating conditions this adaptability establishes an optimal choice for integrating solar energy into modern power systems. MMLI plays a crucial role in facilitating the global shift towards sustainable energy solutions by unification technological innovation, energy efficiency, and environmental responsibility.

Abbreviations

MMLI	Modular Multilevel Inverter
MLI	Multilevel Inverter
MPPT	Maximum Power Point Tracking
MG	Micro Grid
VSC	Voltage Sourced Converter,
DMPPT	Distributed Maximum Power Point Tracking
THD	Total Harmonic Distortion
MMGs	Multi-micro Grids
MMC	Modular Multilevel Converter
PV	Photovoltaic
CHB	Cascaded H-Bridge Converters
P & D	Perturb and Observe
AC	Alternating Current
DC	Direct Current

Author Contributions

Tata Rao Donepudi: Conceptualization, Formal Analysis Investigation, Writing – original draft

Kondala Rao Parasa: Data curation, Formal Analysis

Bhimaraju Pemmanaboidi Srihari Datta: Methodology, isualization

Uma Phanendra Kumar Chaturvedula: Software, Supervision

Anupalli Immanuel: Validation, Writing – review & editing

Conflicts of Interest

The authors declare no conflicts of interest.

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Donepudi, T. R., Parasa, K. R., Datta, B. P. S., Chaturvedula, U. P. K., Immanuel, A. (2026). An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking. Science Discovery Energy, 1(1), 1-13. https://doi.org/10.11648/j.sdenergy.20260101.11

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Donepudi, T. R.; Parasa, K. R.; Datta, B. P. S.; Chaturvedula, U. P. K.; Immanuel, A. An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking. Sci. Discov. Energy 2026, 1(1), 1-13. doi: 10.11648/j.sdenergy.20260101.11

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Donepudi TR, Parasa KR, Datta BPS, Chaturvedula UPK, Immanuel A. An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking. Sci Discov Energy. 2026;1(1):1-13. doi: 10.11648/j.sdenergy.20260101.11

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@article{10.11648/j.sdenergy.20260101.11,
  author = {Tata Rao Donepudi and Kondala Rao Parasa and Bhimaraju Pemmanaboidi Srihari Datta and Uma Phanendra Kumar Chaturvedula and Anupalli Immanuel},
  title = {An Advanced Modular Multilevel Inverters for 
Grid-connected PV Optimization by Maximum Power Point Tracking},
  journal = {Science Discovery Energy},
  volume = {1},
  number = {1},
  pages = {1-13},
  doi = {10.11648/j.sdenergy.20260101.11},
  url = {https://doi.org/10.11648/j.sdenergy.20260101.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.sdenergy.20260101.11},
  abstract = {Modular multilevel inverters (MMLIs), acknowledged not only for its modular structure, scalability and low harmonic distortion but also offers an efficient solution, for managing high-power renewable-energy applications. However, these often depends on conventional centralized control methods, which are insufficient in addressing critical challenges like scalability and hardware delays in distributed control systems. This paper emphases on the design and implementation of an advanced 3-Ph. MMLI for a 400-kW solar plant connected to a 25 kV grid. The study examines the system's performance, control strategies and operational challenges encountered during the integration with grid. To optimize energy extraction from the PV array, incorporate a DC/DC, converter featuring MPPT, through ‘Perturb and Observe’ (P & D) technique. The extracted energy is then stepped up and converted into 3-Ph. AC voltage through MMLI. The output from these, feed into a common 500V DC bus, enabling the overall system integration. Unlike earlier methods which are used open-loop control to address power imbalances among legs, this study employs closed-loop control using to correct mismatched DC loop currents. This allows, dynamic adjustment the voltage across PV array to optimize output efficiency. The efficacy of the proposed control-strategy has been validated through Mat lab/Simulink simulations, demonstrating its potential.},
 year = {2026}
}

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TY - JOUR
T1 - An Advanced Modular Multilevel Inverters for
Grid-connected PV Optimization by Maximum Power Point Tracking
AU - Tata Rao Donepudi
AU - Kondala Rao Parasa
AU - Bhimaraju Pemmanaboidi Srihari Datta
AU - Uma Phanendra Kumar Chaturvedula
AU - Anupalli Immanuel
Y1 - 2026/02/25
PY - 2026
N1 - https://doi.org/10.11648/j.sdenergy.20260101.11
DO - 10.11648/j.sdenergy.20260101.11
T2 - Science Discovery Energy
JF - Science Discovery Energy
JO - Science Discovery Energy
SP - 1
EP - 13
PB - Science Publishing Group
UR - https://doi.org/10.11648/j.sdenergy.20260101.11
AB - Modular multilevel inverters (MMLIs), acknowledged not only for its modular structure, scalability and low harmonic distortion but also offers an efficient solution, for managing high-power renewable-energy applications. However, these often depends on conventional centralized control methods, which are insufficient in addressing critical challenges like scalability and hardware delays in distributed control systems. This paper emphases on the design and implementation of an advanced 3-Ph. MMLI for a 400-kW solar plant connected to a 25 kV grid. The study examines the system's performance, control strategies and operational challenges encountered during the integration with grid. To optimize energy extraction from the PV array, incorporate a DC/DC, converter featuring MPPT, through ‘Perturb and Observe’ (P & D) technique. The extracted energy is then stepped up and converted into 3-Ph. AC voltage through MMLI. The output from these, feed into a common 500V DC bus, enabling the overall system integration. Unlike earlier methods which are used open-loop control to address power imbalances among legs, this study employs closed-loop control using to correct mismatched DC loop currents. This allows, dynamic adjustment the voltage across PV array to optimize output efficiency. The efficacy of the proposed control-strategy has been validated through Mat lab/Simulink simulations, demonstrating its potential.
VL - 1
IS - 1
ER -

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Author Information

Tata Rao Donepudi

Department of Electrical and Electronics Engineering, Aditya University, Surampalem, India

Biography: Tata Rao Donepudi, working as Assistant Professor in the Department of Electrical and Electronics Engineering in Aditya University, Surampalem, Andhra Pradesh, India. His Research areas include Power Systems, Power Electronics and Electrical Vehicles. He has two years of Industrial experience and more than twenty years of teaching experience and two years industrial experience He has published various research papers in national and international journals and conferences. He is a member of ISTE, IETE and IAENG.

Contact Email

http://orcid.org/0009-0002-2179-0841
Kondala Rao Parasa

Department of Electrical and Electronics Engineering, Aditya University, Surampalem, India

Biography: Kondala Rao Parasa, designated as Assistant Professor in the Department of Electrical and Electronics Engineering in Aditya University, Surampalem, Andhra Pradesh. His research areas include power system operation & Control Systems and Electrical Power Distribution systems. He has more than ten 10 years teaching experience and published various research papers in national and international journals and conferences. He is a member of IETE and IAENG.

Contact Email

http://orcid.org/0009-0004-2062-6382
Bhimaraju Pemmanaboidi Srihari Datta

Department of Electrical and Electronics Engineering, Aditya University, Surampalem, India

Biography: Bhimaraju Pemmanaboidi Srihari Datta, working as an Assistant Professor in the Department of Electrical and Electronics Engineering, Aditya University, Surampalem, Andhra Pradesh, India. His research interests are Power Quality, Electric Vehicles and Smart Grids. He has more than 15 years teaching experience and published various research papers in national and international journals and conferences. He is a member of IAENG and IETE.

Contact Email

http://orcid.org/0000-0002-4855-7284
Uma Phanendra Kumar Chaturvedula

Department of Electrical and Electronics Engineering, Aditya University, Surampalem, India

Biography: Uma Phanendra Kumar Chaturvedula, an accomplished academic and a dedicated Assistant Professor in the Department of Electrical and Electronics Engineering in Aditya University, Surampalem, Andhra Pradesh. His research interests include in the cutting-edge areas of smart grids, Power System Optimization, and Electrical Power Distribution systems. He served as a reviewer for several esteemed international journals and conferences. He is a member of ISTE, IETE and IAENG. His enduring contributions continue to inspire and influence the field of Electrical and Electronics Engineering.

Contact Email

http://orcid.org/0000-0003-1612-9784
Anupalli Immanuel

Department of Electrical and Electronics Engineering, Gayathri Institute of Technology and Management, Hyderabad, India

Biography: Anupalli Immanuel, an academician, researcher, and innovator in Electrical and Electronics Engineering. He received his B. Tech., M. Tech., and Ph. D. in Electrical and Electronics Engineering from Sri Venkteswara University, Tirupati. With over 18 years of academic and research experience, he has secured research funding from DST-SEED, Atal Innovation Mission, NITI Aayog, and MSME, Government of India. He has authored 30 research publications in reputed international journals and conferences, authored two books, holds two patents, and supervising Seven doctoral scholars. He is frequently invited to deliver lectures on fuzzy logic & Neural Networks, Innovation, Incubation & startups, research methodology, technical writing, and Electric Vehicles. His international exposure includes visits to Hong Kong (2014) and Germany (2019). A professional member of IEEE and Student Branch Counsellor at ASCET, his research interests span power systems, control systems, fuzzy logic, optimization, electric vehicles.

Contact Email

http://orcid.org/0000-0003-1713-3101

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APA Style

Donepudi, T. R., Parasa, K. R., Datta, B. P. S., Chaturvedula, U. P. K., Immanuel, A. (2026). An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking. Science Discovery Energy, 1(1), 1-13. https://doi.org/10.11648/j.sdenergy.20260101.11

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ACS Style

Donepudi, T. R.; Parasa, K. R.; Datta, B. P. S.; Chaturvedula, U. P. K.; Immanuel, A. An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking. Sci. Discov. Energy 2026, 1(1), 1-13. doi: 10.11648/j.sdenergy.20260101.11

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AMA Style

Donepudi TR, Parasa KR, Datta BPS, Chaturvedula UPK, Immanuel A. An Advanced Modular Multilevel Inverters for Grid-connected PV Optimization by Maximum Power Point Tracking. Sci Discov Energy. 2026;1(1):1-13. doi: 10.11648/j.sdenergy.20260101.11

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@article{10.11648/j.sdenergy.20260101.11,
  author = {Tata Rao Donepudi and Kondala Rao Parasa and Bhimaraju Pemmanaboidi Srihari Datta and Uma Phanendra Kumar Chaturvedula and Anupalli Immanuel},
  title = {An Advanced Modular Multilevel Inverters for 
Grid-connected PV Optimization by Maximum Power Point Tracking},
  journal = {Science Discovery Energy},
  volume = {1},
  number = {1},
  pages = {1-13},
  doi = {10.11648/j.sdenergy.20260101.11},
  url = {https://doi.org/10.11648/j.sdenergy.20260101.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.sdenergy.20260101.11},
  abstract = {Modular multilevel inverters (MMLIs), acknowledged not only for its modular structure, scalability and low harmonic distortion but also offers an efficient solution, for managing high-power renewable-energy applications. However, these often depends on conventional centralized control methods, which are insufficient in addressing critical challenges like scalability and hardware delays in distributed control systems. This paper emphases on the design and implementation of an advanced 3-Ph. MMLI for a 400-kW solar plant connected to a 25 kV grid. The study examines the system's performance, control strategies and operational challenges encountered during the integration with grid. To optimize energy extraction from the PV array, incorporate a DC/DC, converter featuring MPPT, through ‘Perturb and Observe’ (P & D) technique. The extracted energy is then stepped up and converted into 3-Ph. AC voltage through MMLI. The output from these, feed into a common 500V DC bus, enabling the overall system integration. Unlike earlier methods which are used open-loop control to address power imbalances among legs, this study employs closed-loop control using to correct mismatched DC loop currents. This allows, dynamic adjustment the voltage across PV array to optimize output efficiency. The efficacy of the proposed control-strategy has been validated through Mat lab/Simulink simulations, demonstrating its potential.},
 year = {2026}
}

Copy | Download