A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology

This paper examines the voltage and current (V-I) stability and harmonic reduction in a decentralized DC microgrid with two parallel-connected inverters under unbalanced load conditions. However, oscillations were observed in systems with parallel converters by connecting them with non-linear loads...

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Main Authors: J. Venumadhav, Durgam Rajababu, CH Hussain Bhasha
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590123025021097
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author J. Venumadhav
Durgam Rajababu
CH Hussain Bhasha
author_facet J. Venumadhav
Durgam Rajababu
CH Hussain Bhasha
author_sort J. Venumadhav
collection DOAJ
description This paper examines the voltage and current (V-I) stability and harmonic reduction in a decentralized DC microgrid with two parallel-connected inverters under unbalanced load conditions. However, oscillations were observed in systems with parallel converters by connecting them with non-linear loads and by operating with unbalanced loads. The system incorporates current and voltage controllers, a droop controller for reactive power (VAR), and active or real power (KW) sharing. Stability is improved when comparing isolated or grid-connected systems to voltage-current (VI) droop control, which acts as a resistor, and conventional droop control methods that depend on the relationships between reactive power (VAR) and voltage (V), real power (KW), and frequency (Hz), and by using voltage-current droops when droop coefficients have low values. The harmonics in parallel inverters are reduced by incorporating proper PI controllers in LCL filters and by choosing proper droop coefficients. The study develops different control strategies to reduce oscillations in voltage and current output waveforms and reduce THD’s to 1 to 8 % in a two-parallel connected voltage source inverter Simulink model of the system, based on the conversion of three-phase time-variant quantities to two-phase time-variant quantities. This model integrates an LCL filter, a droop controller, a voltage controller, and a current controller. MATLAB/Sim Power Systems is used for developing the proposed system.
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spelling doaj-art-0e4a82989b1c4b70a7243673e5c59db62025-07-09T04:32:46ZengElsevierResults in Engineering2590-12302025-09-0127106037A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technologyJ. Venumadhav0Durgam Rajababu1CH Hussain Bhasha2The Centre for Emerging Energy Technologies (CEET) , Department of Electrical and Electronics Engineering, SR University, Warangal, 506371 IndiaThe Centre for Emerging Energy Technologies (CEET) , Department of Electrical and Electronics Engineering, SR University, Warangal, 506371 IndiaCorresponding author.; The Centre for Emerging Energy Technologies (CEET) , Department of Electrical and Electronics Engineering, SR University, Warangal, 506371 IndiaThis paper examines the voltage and current (V-I) stability and harmonic reduction in a decentralized DC microgrid with two parallel-connected inverters under unbalanced load conditions. However, oscillations were observed in systems with parallel converters by connecting them with non-linear loads and by operating with unbalanced loads. The system incorporates current and voltage controllers, a droop controller for reactive power (VAR), and active or real power (KW) sharing. Stability is improved when comparing isolated or grid-connected systems to voltage-current (VI) droop control, which acts as a resistor, and conventional droop control methods that depend on the relationships between reactive power (VAR) and voltage (V), real power (KW), and frequency (Hz), and by using voltage-current droops when droop coefficients have low values. The harmonics in parallel inverters are reduced by incorporating proper PI controllers in LCL filters and by choosing proper droop coefficients. The study develops different control strategies to reduce oscillations in voltage and current output waveforms and reduce THD’s to 1 to 8 % in a two-parallel connected voltage source inverter Simulink model of the system, based on the conversion of three-phase time-variant quantities to two-phase time-variant quantities. This model integrates an LCL filter, a droop controller, a voltage controller, and a current controller. MATLAB/Sim Power Systems is used for developing the proposed system.http://www.sciencedirect.com/science/article/pii/S2590123025021097Conventional V-I droopCurrent controller microgridLCL filterVoltage controller droop coefficients
spellingShingle J. Venumadhav
Durgam Rajababu
CH Hussain Bhasha
A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology
Results in Engineering
Conventional V-I droop
Current controller microgrid
LCL filter
Voltage controller droop coefficients
title A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology
title_full A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology
title_fullStr A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology
title_full_unstemmed A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology
title_short A novel analysis of two parallel connected inverters for isolated DC microgrid system by using droop controller technology
title_sort novel analysis of two parallel connected inverters for isolated dc microgrid system by using droop controller technology
topic Conventional V-I droop
Current controller microgrid
LCL filter
Voltage controller droop coefficients
url http://www.sciencedirect.com/science/article/pii/S2590123025021097
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