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arxiv: 1907.03080 · v1 · pith:5S6B4UJ7new · submitted 2019-07-06 · 📡 eess.SY · cs.SY

A Reconfigurable Solar Photovoltaic Grid-Tied Inverter Architecture for Enhanced Energy Access in Backup Power Applications

Venkatramanan D , Vinod John This is my paper

Pith reviewed 2026-05-25 01:58 UTC · model grok-4.3

classification 📡 eess.SY cs.SY
keywords reconfigurable grid-tied invertersolar photovoltaicUPS backup powerbattery emulationgrid outage operationDC-DC charge controllerparallel battery operationpower management
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The pith

A solar inverter reconfigures during outages to charge a UPS battery bank without any communication link.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper proposes a photovoltaic reconfigurable grid-tied inverter that functions as a standard grid-tied inverter when the grid is available but switches to a DC-DC charge-controller mode during outages. It connects directly to the battery bank of an external UPS backup system and supplies solar power to reduce the battery's discharge. This parallel operation is made possible by a battery emulation control scheme that avoids any need to communicate with the UPS or its battery management system. A higher-level power management layer adjusts for changing sunlight and load conditions throughout the day. The entire architecture is designed to work with UPS units from any manufacturer and was validated on a 4 kVA hardware prototype.

Core claim

The central claim is that a reconfigurable grid-tied inverter (RGTI) can be built so that it operates as a conventional GTI on-grid and, during a grid outage, reconfigures as a DC-DC charge-controller tied to an external UPS battery bank. A battery emulation control scheme allows the RGTI to run in parallel with the physical UPS battery, thereby lowering the battery's discharge current. System-level control then manages solar irradiation changes and UPS load variations to keep battery discharge as low as possible. The design requires no communication with the UPS and remains independent of the UPS manufacturer.

What carries the argument

The battery emulation control scheme, which lets the RGTI mimic the behavior of a physical battery so that it can operate in parallel with the UPS battery bank without conflicting with the UPS battery management system.

If this is right

  • Solar power continues to reach the UPS battery bank during grid outages instead of the inverter shutting down.
  • Physical UPS battery discharge current drops because the RGTI supplies part of the load current through emulation.
  • No communication hardware or protocol changes are needed inside the existing UPS.
  • Dynamic solar and load variations are handled automatically so that battery use stays minimized across the day.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same emulation idea could be applied to other backup systems that already contain batteries, extending solar contribution without new communication infrastructure.
  • In areas with frequent short outages the approach would increase the effective energy delivered by rooftop solar before batteries are needed.
  • Manufacturers of small-scale UPS units could add an auxiliary input port that accepts such emulated-battery chargers as a standard feature.

Load-bearing premise

The RGTI can be controlled to emulate battery behavior closely enough that it never conflicts with the UPS battery management system and can do so without any communication to the UPS.

What would settle it

Run the RGTI in parallel with a real UPS battery bank during a simulated outage and observe whether the UPS battery management system issues a fault, reduces charging current, or shuts down the system.

Figures

Figures reproduced from arXiv: 1907.03080 by Venkatramanan D, Vinod John.

Figure 1
Figure 1. Figure 1: Functional block schematic of a GTI and UPS in a [PITH_FULL_IMAGE:figures/full_fig_p001_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Block schematic of (a) hybrid PV system and (b) [PITH_FULL_IMAGE:figures/full_fig_p002_2.png] view at source ↗
Figure 1
Figure 1. Figure 1: It is intended that the GTI is not kept idle and continues [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 3
Figure 3. Figure 3: It comprises an H-bridge inverter with unipolar PWM, [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: (a) Control schematic of RGTI operating in grid-tied mode performing MPPT, and (b) equivalent circuit schematic of [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Battery emulation control schemes showing (a) basic [PITH_FULL_IMAGE:figures/full_fig_p004_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Control schematic of RGTI in battery-tied mode [PITH_FULL_IMAGE:figures/full_fig_p005_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: (a) Experimental setup, and profiles of vpv, ig, iL and ipv in grid-tied mode for (b) 40% step change in current loop reference I ∗ q for inner loop, (c) 10% step change in voltage loop reference v ∗ pv. (a) (b) 0 2 4 6 8 10 −100 0 100 200 300 400 500 600 time (s) Voltage (V) 0 2 4 6 8 10−5 0 5 10 15 20 25 30 Current (A) vpv iB iL (c) [PITH_FULL_IMAGE:figures/full_fig_p007_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: (a) MPPT performance in grid-tied mode, (b) MPPT performance in battery-tied mode, and (c) simulated dynamic [PITH_FULL_IMAGE:figures/full_fig_p007_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: (a) Measured performance of battery-current controller for a 30 [PITH_FULL_IMAGE:figures/full_fig_p007_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Dynamic model of the RGTI in battery-tied mode [PITH_FULL_IMAGE:figures/full_fig_p008_10.png] view at source ↗
read the original abstract

In this paper, a photovoltaic (PV) reconfigurable grid-tied inverter (RGTI) scheme is proposed. Unlike a conventional GTI that ceases operation during a power outage, the RGTI is designed to act as a regular GTI in the on-grid mode but it is reconfigured to function as a DC-DC charge-controller that continues operation during a grid outage. During this period, the RGTI is tied to the battery-bank of an external UPS based backup power system to augment it with solar power. Such an operation in off-grid mode without employing communication with the UPS is challenging, as the control of RGTI must not conflict with the battery management system of the UPS. The hardware and control design aspects of this requirement are discussed in this paper. A battery emulation control scheme is proposed for the RGTI that facilitates seamless functioning of the RGTI in parallel with the physical UPS battery to reduce its discharge current. A system-level control scheme for overall operation and power management is presented to handle the dynamic variations in solar irradiation and UPS loads during the day, such that the battery discharge burden is minimized. The design and operation of the proposed RGTI system are independent of the external UPS and can be integrated with an UPS supplied by any manufacturer. Experimental results on a 4~kVA hardware setup validate the proposed RGTI concept, its operation and control.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The paper proposes a reconfigurable grid-tied inverter (RGTI) for PV systems that operates as a standard GTI during grid availability but reconfigures as a DC-DC charge controller during outages to supply solar power to an external UPS battery bank. A battery emulation control scheme enables parallel operation with the physical UPS battery without communication to reduce discharge current, and a system-level power management strategy handles solar and load variations. The design is claimed to be independent of the specific UPS manufacturer, with experimental validation on a 4 kVA hardware prototype.

Significance. If the battery emulation enables reliable parallel operation across UPS systems, the architecture offers a practical way to augment existing backup power installations with PV without hardware modifications or communication links, potentially extending backup duration and reducing grid dependence in unreliable power environments. The 4 kVA hardware demonstration provides direct evidence of concept feasibility for the tested configuration and control approach.

major comments (1)
  1. [Abstract] Abstract: the claim that 'the design and operation of the proposed RGTI system are independent of the external UPS and can be integrated with an UPS supplied by any manufacturer' is load-bearing for the no-communication parallel operation but is supported only by results from a single 4 kVA setup; no characterization of BMS variations (voltage thresholds, current sensing methods, or fault logic) across manufacturers is provided to confirm the emulation scheme's generality.
minor comments (1)
  1. The manuscript would benefit from explicit discussion of how the battery emulation parameters were selected or tuned for the tested UPS to allow reproducibility.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the detailed review and constructive comment on our manuscript. We address the major comment point-by-point below.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the claim that 'the design and operation of the proposed RGTI system are independent of the external UPS and can be integrated with an UPS supplied by any manufacturer' is load-bearing for the no-communication parallel operation but is supported only by results from a single 4 kVA setup; no characterization of BMS variations (voltage thresholds, current sensing methods, or fault logic) across manufacturers is provided to confirm the emulation scheme's generality.

    Authors: The battery emulation control is designed to replicate the terminal voltage and current behavior of a standard lead-acid battery at the DC interface. This electrical-level matching allows the UPS BMS to treat the RGTI output as an extension of the battery bank without requiring manufacturer-specific data, communication, or knowledge of internal thresholds. The approach therefore relies on the common physical interface used by the majority of UPS systems rather than proprietary BMS logic. While the experimental validation is indeed limited to one 4 kVA unit, the control law itself does not embed any UPS-specific parameters, supporting the generality claim on design grounds. We do not revise the manuscript, as the presented evidence is consistent with the stated design principles. revision: no

Circularity Check

0 steps flagged

No circularity: hardware design validated by experiment

full rationale

The paper describes a reconfigurable inverter architecture, battery emulation control, and system-level power management, all validated experimentally on a 4 kVA prototype. No equations, fitted parameters, or predictions are presented that reduce claimed performance to quantities defined by the authors' own inputs. The design claims rest on hardware implementation and measured results rather than any self-referential derivation chain.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review provides no explicit free parameters, axioms, or invented entities; the design implicitly rests on standard power-electronics assumptions (switching converter models, battery terminal voltage behavior) and control-theory stability criteria that are not enumerated.

pith-pipeline@v0.9.0 · 5790 in / 1214 out tokens · 30074 ms · 2026-05-25T01:58:40.942056+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

29 extracted references · 29 canonical work pages

  1. [1]

    Multilevel inverter topology for renewable energy grid integration,

    S. Amamra, K. Meghriche, A. Cherifi, and B. Francois, “Multilevel inverter topology for renewable energy grid integration,” IEEE Trans. Ind. Electron., vol. 64, no. 11, pp. 8855–8866, Nov. 2017

    work page 2017

  2. [2]

    Grid inter- connection of renewable energy sources at the distribution level with power-quality improvement features,

    M. Singh, V . Khadkikar, A. Chandra, and R. K. Varma, “Grid inter- connection of renewable energy sources at the distribution level with power-quality improvement features,” IEEE Trans. Power Del., vol. 26, no. 1, pp. 307–315, Jan. 2011

    work page 2011

  3. [3]

    Design and implementation of distributed control architecture of an ac-stacked pv inverter,

    H. Jafarian, I. Mazhari, B. Parkhideh, S. Trivedi, D. Somayajula, R. Cox, and S. Bhowmik, “Design and implementation of distributed control architecture of an ac-stacked pv inverter,” inProc. IEEE Energy Convers. Congr. Expo. (ECCE), pp. 1130–1135, Sep. 2015

    work page 2015

  4. [4]

    Overview of control and grid synchronization for distributed power generation systems,

    F. Blaabjerg, R. Teodorescu, M. Liserre, and A. V . Timbus, “Overview of control and grid synchronization for distributed power generation systems,” IEEE Trans. Ind. Electron. , vol. 53, no. 5, pp. 1398–1409, Oct. 2006

    work page 2006

  5. [5]

    Performance evaluation of three-phase grid-connected photovoltaic inverters using electrolytic or polypropylene film capacitors,

    B. Karanayil, V . G. Agelidis, and J. Pou, “Performance evaluation of three-phase grid-connected photovoltaic inverters using electrolytic or polypropylene film capacitors,” IEEE Transactions on Sustainable Energy, vol. 5, no. 4, pp. 1297–1306, Oct. 2014

    work page 2014

  6. [6]

    Design optimization of transformerless grid-connected pv inverters including reliability,

    E. Koutroulis and F. Blaabjerg, “Design optimization of transformerless grid-connected pv inverters including reliability,” IEEE Transactions on Power Electronics, vol. 28, no. 1, pp. 325–335, Jan. 2013

    work page 2013

  7. [7]

    Teodorescu, M

    R. Teodorescu, M. Liserre, P. Rodriguez, and F. Blaabjerg, Grid Con- verters for Photovoltaic and Wind Power Systems , vol. 29. John Wiley & Sons, 2011

    work page 2011

  8. [8]

    Positive-feedback- based active anti-islanding schemes for inverter-based distributed gener- ators: Basic principle, design guideline and performance analysis,

    P. Du, Z. Ye, E. E. Aponte, J. K. Nelson, and L. Fan, “Positive-feedback- based active anti-islanding schemes for inverter-based distributed gener- ators: Basic principle, design guideline and performance analysis,” IEEE Trans. Power Electron., vol. 25, no. 12, pp. 2941–2948, Dec. 2010

    work page 2010

  9. [9]

    IEEE standard for interconnecting distributed resources with electric power systems,

    “IEEE standard for interconnecting distributed resources with electric power systems,” IEEE Std 1547-2018 , May. 2018

    work page 2018

  10. [10]

    High-performance transformer- less online ups,

    J. Park, J. Kwon, E. Kim, and B. Kwon, “High-performance transformer- less online ups,” IEEE Trans. Ind. Electron. , vol. 55, no. 8, pp. 2943– 2953, Aug. 2008

    work page 2008

  11. [11]

    An online ups system that eliminates the inrush current phenomenon while feeding multiple load transformers,

    S. S. H. Bukhari, T. A. Lipo, and B. Kwon, “An online ups system that eliminates the inrush current phenomenon while feeding multiple load transformers,” IEEE Trans. Ind. Appl. , vol. 53, no. 2, pp. 1149–1156, Mar. 2017

    work page 2017

  12. [12]

    Hybrid solar inverter based on a standard power electronic cell for microgrids applications,

    L. Arnedo, S. Dwari, V . Blasko, and A. Kroeber, “Hybrid solar inverter based on a standard power electronic cell for microgrids applications,” in Proc. IEEE Energy Convers. Congr. Expo. (ECCE) , pp. 961–967. IEEE, 2011

    work page 2011

  13. [13]

    80 kw hybrid solar inverter for standalone and grid connected applications,

    L. Arnedo, S. Dwari, V . Blasko, and S. Park, “80 kw hybrid solar inverter for standalone and grid connected applications,” in Proc. IEEE Applied Power Electron. Conf. Expo. (APEC) , pp. 270–276, Feb. 2012

    work page 2012

  14. [14]

    Advanced techniques for integra- tion of energy storage and photovoltaic generator in renewable energy systems,

    S. Dwari, L. Arnedo, and V . Blasko, “Advanced techniques for integra- tion of energy storage and photovoltaic generator in renewable energy systems,” in Proc. IEEE Energy Convers. Congr. Expo. (ECCE) , pp. 395–401, Sep. 2014

    work page 2014

  15. [15]

    Load priority control strategy for spv-ups system,

    C. Cavallaro, S. Musumeci, C. Santonocito, and M. Pappalardo, “Load priority control strategy for spv-ups system,” in Proc. Power Electron. Electr. Drives Automation Motion (SPEEDAM), pp. 1207–1212. IEEE, 2010

    work page 2010

  16. [16]

    Research and analysis of the improved inverse- droop control strategy for dual mode inverters in micro grid,

    C. Wen and J. Jia, “Research and analysis of the improved inverse- droop control strategy for dual mode inverters in micro grid,” in Proc. IET Electr. Engg. Academic Forum, Tsinghua University , pp. 1–6, May. 2016

    work page 2016

  17. [17]

    Dual mode operational control of single stage pv-battery based microgrid,

    Shatakshi, B. Singh, and S. Mishra, “Dual mode operational control of single stage pv-battery based microgrid,” in Proc. IEEMA Engineer Infinite Conf. (eTechNxT), pp. 1–5, Mar. 2018

    work page 2018

  18. [18]

    Standalone hybrid wind-solar power gener- ation system applying dump power control without dump load,

    T. Hirose and H. Matsuo, “Standalone hybrid wind-solar power gener- ation system applying dump power control without dump load,” IEEE Trans. Ind. Electron., vol. 59, no. 2, pp. 988–997, Feb. 2012

    work page 2012

  19. [19]

    Design and implementation of active power control with improved p &o method for wind-pv-battery-based standalone generation system,

    M. Rezkallah, A. Hamadi, A. Chandra, and B. Singh, “Design and implementation of active power control with improved p &o method for wind-pv-battery-based standalone generation system,” IEEE Trans. Ind. Electron., vol. 65, no. 7, pp. 5590–5600, Jul. 2018

    work page 2018

  20. [20]

    Comparison of pv-battery architectures for res- idential applications,

    I. Sulaeman, V . Vega-Garita, G. R. C. Mouli, N. Narayan, L. Ramirez- Elizondo, and P. Bauer, “Comparison of pv-battery architectures for res- idential applications,” in Proc. IEEE Int. Energy Conf. (ENERGYCON) , pp. 1–7, Apr. 2016

    work page 2016

  21. [21]

    Analysis of load shedding strategies for battery management in pv-based rural off-grids,

    J. Sridhar, G. R. C. Mouli, P. Bauer, and E. Raaijen, “Analysis of load shedding strategies for battery management in pv-based rural off-grids,” in IEEE Eindhoven PowerTech(POWERTECH), pp. 1–6, Jun. 2015

    work page 2015

  22. [22]

    Three of a kind ups topologies, iec standard,

    S. Karve, “Three of a kind ups topologies, iec standard,” IEE Review, vol. 46, no. 2, pp. 27–31, Mar. 2000

    work page 2000

  23. [23]

    Improved transformerless in- verter with common-mode leakage current elimination for a photovoltaic grid-connected power system,

    B. Yang, W. Li, Y . Gu, W. Cui, and X. He, “Improved transformerless in- verter with common-mode leakage current elimination for a photovoltaic grid-connected power system,” IEEE Trans. Power Electron. , vol. 27, no. 2, pp. 752–762, Feb. 2012

    work page 2012

  24. [24]

    A direct maximum power point tracking method for single-phase grid-connected pv inverters,

    F. El Aamri, H. Maker, D. Sera, S. V . Spataru, J. M. Guerrero, and A. Mouhsen, “A direct maximum power point tracking method for single-phase grid-connected pv inverters,” IEEE Trans. Power Electron., vol. 33, no. 10, pp. 8961–8971, Oct. 2018

    work page 2018

  25. [25]

    Stationary frame current regulation of pwm inverters with zero steady state error,

    D. N. Zmood and D. G. Holmes, “Stationary frame current regulation of pwm inverters with zero steady state error,” in Proc. IEEE Power Electron. Specialists Conf. (PESC) , vol. 2, pp. 1185–1190, Jul. 1999

    work page 1999

  26. [26]

    Current control loop design and analysis based on resonant regulators for microgrid applications,

    F. de Bosio, M. Pastorelli, L. A. d. S. Ribeiro, M. S. Lima, F. Freijedo, and J. M. Guerrero, “Current control loop design and analysis based on resonant regulators for microgrid applications,” in Proc. IEEE Ind. Electron. Soc. Conf. (IECON) , pp. 005 322–005 327, Nov. 2015

    work page 2015

  27. [27]

    Comparison of photovoltaic array max- imum power point tracking techniques,

    T. Esram and P. L. Chapman, “Comparison of photovoltaic array max- imum power point tracking techniques,” IEEE Trans. Energy Convers. , vol. 22, no. 2, pp. 439–449, Jun. 2007

    work page 2007

  28. [28]

    Femia, G

    N. Femia, G. Petrone, G. Spagnuolo, and M. Vitelli, Power electronics and control techniques for maximum energy harvesting in photovoltaic systems. CRC press, 2017

    work page 2017

  29. [29]

    R. W. Erickson and D. Maksimovic, Fundamentals of power electronics. Springer Science & Business Media, 2007. IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    work page 2007