A Novel Droop-Based Average Voltage Sharing Control Strategy for DC Microgrids

Huang, Po-Hsu; Liu, Po-Chun; Xiao, Weidong; Moursi, Mohamed Shawky El

doi:10.1109/tsg.2014.2357179

Cited by 184 publications

(95 citation statements)

References 19 publications

(5 reference statements)

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“…The main objective of a coordinated control system is to prevent over stressing of any energy source and properly distribute the total power load to each DG in proportion to their rated powers [7,8]. To realise this, the so called droop control which employs own electrical parameters as global indicators is widely applied in MG systems due to its decentralised characteristic [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Decentralised control method for DC microgrids with improved current sharing accuracy

Yang

Jin

et al. 2017

IET Generation, Transmission & Distribution

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A decentralised control method that deals with current sharing issues in dc microgrids (MGs) is proposed in this study. The proposed method is formulated in terms of 'modified global indicator' concept, which was originally proposed to improve reactive power sharing in ac MGs. In this work, the 'modified global indicator' concept is extended to coordinate dc MGs, which aims to preserve the main features offered by decentralised control methods such as no need of communication links, central controller or knowledge of the microgrid topology and parameters. This global indicator is inserted between current and voltage variables by adopting a virtual capacitor, which directly produces an output current sharing performance that is less relied on mismatches of the multi-bus network. Meanwhile, a voltage stabiliser is complementary developed to maintain output voltage magnitude at steady state through a shunt virtual resistance. The operation under multiple dc-buses is also included in order to enhance the applicability of the proposed controller. A detailed mathematical model including the effect of network mismatches is derived for analysis of the stability of the proposed controller. The feasibility and effectiveness of the proposed control strategy are validated by simulation and experimental results.

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Section: Introductionmentioning

confidence: 99%

Decentralised control method for DC microgrids with improved current sharing accuracy

Yang

Jin

et al. 2017

IET Generation, Transmission & Distribution

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“…Its main drawback is represented by the poor voltage regulation. To this end, several improvements for droop methods have been developed in [9], [10], [11], [12], [13], trying to restore the voltage to the rated value. However, another critical issue is that traditional droop control results in inaccurate power sharing when the output or line impedances of the paralleled converters are different.…”

Section: Introductionmentioning

confidence: 99%

Power sharing of parallel operated DC-DC converters using current-limiting droop control

Braitor

Konstantopoulos

Kadirkamanathan

2017

2017 25th Mediterranean Conference on Control and Automation (MED)

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Abstract-In this paper, a nonlinear current-limiting droop controller is proposed to achieve accurate power sharing among parallel operated DC-DC boost converters in a DC microgrid application. In particular, the recently developed robust droop controller is adopted and implemented as a dynamic virtual resistance in series with the inductance of each DC-DC boost converter. Opposed to the traditional approaches that use small-signal modeling, the proposed control design takes into account the accurate nonlinear dynamic model of each converter and it is analytically proven that accurate power sharing can be accomplished with an inherent current limitation for each converter independently using input-to-state stability theory. When the load requests more power that exceeds the capacity of the converters, the current-limiting capability of the proposed control method protects the devices by limiting the inductor current of each converter below a given maximum value. Extensive simulation results of two paralleled DC-DC boost converters are presented to verify the power sharing and current-limiting properties of the proposed controller under several changes of the load.

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“…Therefore, the control performance of the interface inverter is the focal point in maintaining the stability of the micro-grid. Various control management and operation strategies for micro-grid have been proposed in the past decades [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Several PQ controlled micro-grids were developed in [7][8][9], where the interface inverter is equivalent to a controlled current source.…”

Section: Introductionmentioning

confidence: 99%

“…A hierarchical control for seamless transition to islanding was also developed [15]. Some other methods for smooth transfer between both grid-connected and islanded modes are investigated in [16][17][18][19][20][21][22][23][24]. Hwang and Park [16] introduced a combined control strategy for seamless mode transitions considering protection of the critical load and operation of the DG inverter without grid fault trip.…”

Section: Introductionmentioning

confidence: 99%

“…In [21,22], the use of a dual-mode inverter was examined, and a micro-grid mode conversion as a preliminary study was proposed, but no more specific solutions were given [6]. A droop controlled dual mode inverter was proposed and developed in [23,24], where the inverter operates in the droop control in both the islanded and grid-connected modes. Therefore, it is beneficial in achieving smooth transfers because there is no need to transfer the control strategy during mode transfer.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Transient Oscillations Analysis and Modified Control Strategy for Seamless Mode Transfer in Micro-Grids: A Wind-PV-ES Hybrid System Case Study

et al. 2015

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Abstract:With the rapid development of the micro-grid associated with new and clean energies, the smooth switching between grid-connected and islanded operation modes of the micro-grid is a key issue that needs to be addressed urgently. In traditional solutions, V/f (Voltage/frequency) control is adopted for the master micro sources when the micro-grid works in islanded mode, while PQ (real and reactive power) control is adopted when in grid-connected mode. However, when the two controllers switch when mode transfer occurs, transient oscillations usually occur and thereafter the dynamic response will be degraded. This paper considers an archetypical micro-grid with Wind-PV-ES (Wind, Photovoltaic and Energy Storage) hybrid system, which forms the basis of our case study. The underlying reason for such transient oscillation is analyzed in this paper. Thereafter a modified control strategy for seamless mode transfer is designed and implemented. An improved PQ control method is designed by which the output of the PQ controller always synchronously tracks the output of the V/f controller for micro-grid switches from islanded mode to grid-connected; furthermore, a dq rotating coordinate synchronization based V/f control method is proposed for transition from grid-connected mode to islanded mode. Finally, experiments and analysis are undertaken on some basic and important operating cases; the results in our case study indicate that the modified control strategy is effective in dominating the micro-grid during mode transfer and thus yielding significantly better performances.

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A Novel Droop-Based Average Voltage Sharing Control Strategy for DC Microgrids

Cited by 184 publications

References 19 publications

Decentralised control method for DC microgrids with improved current sharing accuracy

Decentralised control method for DC microgrids with improved current sharing accuracy

Power sharing of parallel operated DC-DC converters using current-limiting droop control

Transient Oscillations Analysis and Modified Control Strategy for Seamless Mode Transfer in Micro-Grids: A Wind-PV-ES Hybrid System Case Study

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