Aug 2026· Applied Sciences· 0 citations· 35 references
Abstract
Parallel-inverter microgrids are prone to PCC voltage distortion during islanded operation with nonlinear and unbalanced loads. Virtual-impedance methods can reshape inverter output impedance, but they also add control complexity and may introduce extra voltage drops. This paper proposes a droop-based PI-QPR control strategy to improve PCC voltage quality in islanded parallel-inverter microgrids. The droop scheme generates the fundamental voltage and frequency references, and the PI-QPR voltage outer loop regulates the fundamental, negative-sequence, and dominant low-order harmonic voltage components in the dq synchronous reference frame. The PI regulator is used for the fundamental component, while QPR branches at 2ω0 and 6ω0 compensate the negative-sequence component and the dominant fifth- and seventh-order harmonics. No additional virtual-impedance loop is introduced. Two-inverter hardware-in-the-loop (HIL) tests were conducted under nonlinear and unbalanced load conditions. Compared with the traditional voltage controller, the proposed controller reduces the measured three-phase PCC-voltage THD from 5.79–6.02% to 2.41–2.79%, confirming improved PCC voltage quality in the tested islanded condition.
This paper presents a photovoltaic (PV)-assisted Unified Power Quality Conditioner (UPQC) for enhancing power quality in grid-connected microgrids. The main novelty lies in the integration of a Sequence-Aware Gated Attention Neural Network (SA-GANN) and a Chaotic Parrot Optimization Algorithm tuned PI (CPOA-PI) contr...
D. Anitha, K. Premkumar· Scientific Reports· 0 citations
PV-supplied DC microgrids (PV-DCMGs) are well suited to powering many off-grid applications. Droop control is an effective approach for managing sources in microgrids because it improves system reliability and scalability. However, conventional droop control may not satisfy the requirements of PV-DCMGs, in which loads...
Voltage-source-converter-based high-voltage direct-current (VSC-HVDC) transmission is increasingly used for renewable-energy integration, asynchronous-grid interconnection, and dynamic support of weak AC networks. However, fast converter control dynamics, reduced system inertia, and interaction between the inner and ou...
Nagesh Prabhu, D. Shetty· IEEE Access· 0 citations
DC microgrids are low- or medium-voltage networks designed to connect and manage DC-based sources and loads. A key challenge in operating DC microgrids is maintaining the DC voltage within certain predefined limits while ensuring its stability. Droop control, the most common method towards addressing this challenge, en...
Ognjen Stanojev, Jovan Krajacic, Enea Bianda et al.· 0 citations
This script presents an adaptive coordinated Q-V and P-f droop control strategy for the grid-forming inverters operating in low inertia power systems. The proposed controller simultaneously regulates active power frequency and reactive power voltage dynamics through adaptive droop coefficients driven by real time distu...
The increasing penetration of converter-interfaced renewable energy sources poses significant challenges to power quality in modern microgrids, especially under nonlinear and unbalanced load conditions. Conventional virtual-impedance strategies can improve converter-grid interaction; however, the use of fixed parameter...
C. R. Jiménez Román, E. Hernández-Mayoral, M. Madrigal-Martínez et al.· Processes· 0 citations
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