Distributed load sharing and transmission power loss optimisation for DC microgrids

2021 IEEE 12th Energy Conversion Congress &Amp; Exposition - Asia (ECCE-Asia)

et al. 2021

In this paper, the distribution power loss of DC microgrids comprising both line loss and converter loss is modelled as a quadratic function of current allocation coefficients, which is a convex function with constraints. On basis of convex optimization theory, the optimal current allocation coefficients are on-line calculated by Lagrange multiplier method. Then, an adaptive virtual resistance droop control (AVRDC) is proposed to achieve the given current-sharing rate. In the proposed control, the current-sharing error generates additional adaptive virtual resistance. It is known that the sum of virtual resistance and line resistance should be in inverse proportion to current distribution coefficient. By sampling data of two control periods, the line resistance can be identified in real time. In this way, the real-time efficiency optimization control of DC microgrid can be realized, regardless of line resistance variations. The effectiveness of the proposed control strategy is validated by both simulation and experimental results.

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Section: B Distribution Loss Modelling and Convexity Analysismentioning

confidence: 99%

Section: B Adaptive Virtual Resistance Droop Control and Line Resista...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Line Resistance Identification-Based Adaptive Droop Control for Distribution Power Loss Minimization of DC Microgrids

Jiang

2021 IEEE 12th Energy Conversion Congress &Amp; Exposition - Asia (ECCE-Asia)

et al. 2021

show abstract

“…[12]- [16]. However, the converter loss, which may account over 50% of the total distribution power loss [17], has not been considered. Similar to the converter loss of DER systems in AC microgrids [18]- [21], the converter loss in DC microgrids can be calculated based on the quadratic function of the output currents as well [22].…”

mentioning

confidence: 99%

“…Similar to the converter loss of DER systems in AC microgrids [18]- [21], the converter loss in DC microgrids can be calculated based on the quadratic function of the output currents as well [22]. In [17], [22] and [23], both the line loss and converter loss are taken into account as the distribution power loss of DER systems. However, these investigations are based on meshed DC microgrids and the controlled power loss is sub-optimal.…”

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confidence: 99%

Distribution Power Loss Mitigation of Parallel-Connected Distributed Energy Resources in Low-Voltage DC Microgrids Using a Lagrange Multiplier-Based Adaptive Droop Control

Jiang

IEEE Trans. Power Electron.

et al. 2021

This paper presents a Lagrange multiplier-based adaptive droop control to mitigate distribution power loss of parallel-connected distributed energy resource (DER) systems in DC microgrids. The distribution power loss comprising line loss and converter loss can be modelled as a quadratic function of the output currents of the DER systems, which can be optimized by the tertiary-layer Lagrange multiplier method to obtain the optimal output current references for the secondary-layer adaptive droop control. The output currents are compensated by the adaptive droop control to provide output voltage references for the primary-layer local dual-loop control, which is a conventional local control scheme for the regulations of gridconnected DC/DC converters. Both simulation and experimental results validate that the proposed control strategy can reduce the distribution power loss of parallel-connected DER systems in 48 V DC microgrids as compared to the conventional control strategy by only optimizing the line loss in different cases.

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Control Algorithms for Energy Storage Systems to Reduce Distribution Power Loss of Microgrids

Active Electrical Distribution Network

Hui

2021