Study on the Influence of Distribution Lines to Parallel Inverter Systems Adopting the Droop Control Method

Zhang, Xuan; Liu, Jinjun; You, Zhiyuan; Liu, Ting

doi:10.6113/jpe.2013.13.4.701

Cited by 12 publications

(5 citation statements)

References 26 publications

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“…For the simulation and experiments in this paper, in order to achieve a good sharing of virtual power, a PCC Q V  based indirect voltage control proposed in [20] is selected to be implemented into the unified virtual power based decoupling method. The power sharing strategy in [20] uses the PCC voltage PCC V to indirectly control reactive power Q.…”

Section: A Basic Ideamentioning

confidence: 99%

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A Unified Virtual Power Decoupling Method for Droop-Controlled Parallel Inverters in Microgrids

Wu¹,

Liu²,

Liu³

et al. 2016

IEEE Trans. Power Electron.

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157

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The coupling between the active and the reactive power of the droop-controlled inverter is critical in the low voltage microgrid. The conventional virtual power based control strategy can decouple the active and the reactive power of the inverter, whereas the active power of the load is probably not equally shared among the parallel inverters in the microgrid. To tackle this issue, this paper proposes an improved virtual power based control method for the droop controlled parallel inverters with a unified rotation angle in the power transformation. Meanwhile, the optimal value of the unified rotation angle is rigorously derived through investigating the relative stability of the system by innovatively adopting Routh Stability Criterion. Moreover, the proposed method is enhanced by introducing low pass filters (LPFs) in the coupling path for further mitigating the coupling between the active and the reactive power of the inverter. Additionally, the stability analysis and parameter design for the proposed method are comprehensively presented. Finally, the effectiveness of the proposed method is validated by the simulation and experimental results.Index Terms-Droop control, microgrid, parallel inverters, power decoupling, virtual power.

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Section: A Basic Ideamentioning

confidence: 99%

“…The power sharing strategy in [20] uses the PCC voltage PCC V to indirectly control reactive power Q. Differently, in order to combine this power sharing strategy with the proposed decoupling method, the PCC voltage is used here to share the virtual reactive power Q .…”

Section: A Basic Ideamentioning

confidence: 99%

A Unified Virtual Power Decoupling Method for Droop-Controlled Parallel Inverters in Microgrids

Wu¹,

Liu²,

Liu³

et al. 2016

IEEE Trans. Power Electron.

Self Cite

157

View full text Add to dashboard Cite

show abstract

“…In references [25,26], the line impedance influence on the control scheme for two parallel operated inverters was described. This paper proposes an improved droop control scheme for reactive power sharing in two parallel-connected DGs through unequal line impedances, in which the voltage drop due to the line impedance is compensated by feed-forwarding.…”

Section: Droop Control Conceptmentioning

confidence: 99%

A New Reactive-Power Sharing Scheme for Two Inverter-Based Distributed Generations with Unequal Line Impedances in Islanded Microgrids

et al. 2017

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This paper proposes a new reactive-power sharing scheme to reduce the circulating current when two inverter-based distributed generations (DGs) operate in parallel through unequal line impedances in an islanded microgrid. If the terminal voltages of the two DGs are not equal due to the unequal line impedances, a circulating current due to reactive-power unbalance occurs, which increases system loss. The proposed droop control compensates the terminal voltage difference to reduce the circulating current by considering a feed-forward path of the line voltage drop. The feasibility of the proposed droop control was first verified through computer simulations, and then experiments with a hardware set-up in the lab. The experimental results were compared with the simulation results to confirm the feasibility of the proposed droop control.

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“…However, the conventional droop control method is subjected to inherent limitations of power sharing. Although real power-frequency droop (P-f droop) can share real power accurately, reactive power sharing with reactive power-voltage amplitude droop (Q-V droop) is sensitive to DG output impedance and transmission line impedance [5]- [7]. In practical microgrids, feeders may have both non-trivial inductive and resistive components.…”

Section: Introductionmentioning

confidence: 99%

Secondary Voltage Control for Reactive Power Sharing in an Islanded Microgrid

Guo¹,

Wu²,

Lin³

et al. 2016

Journal of Power Electronics

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Owing to mismatched feeder impedances in an islanded microgrid, the conventional droop control method typically results in errors in reactive power sharing among distributed generation (DG) units. In this study, an improved droop control strategy based on secondary voltage control is proposed to enhance the reactive power sharing accuracy in an islanded microgrid. In a DG local controller, an integral term is introduced into the voltage droop function, in which the voltage compensation signal from the secondary voltage control is utilized as the common reactive power reference for each DG unit. Therefore, accurate reactive power sharing can be realized without any power information exchange among DG units or between DG units and the central controller. Meanwhile, the voltage deviation in the microgrid common bus is removed. Communication in the proposed strategy is simple to implement because the information of the voltage compensation signal is broadcasted from the central controller to each DG unit. The reactive power sharing accuracy is also not sensitive to time-delay mismatch in the communication channels. Simulation and experimental results are provided to validate the effectiveness of the proposed method.

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Study on the Influence of Distribution Lines to Parallel Inverter Systems Adopting the Droop Control Method

Cited by 12 publications

References 26 publications

A Unified Virtual Power Decoupling Method for Droop-Controlled Parallel Inverters in Microgrids

A Unified Virtual Power Decoupling Method for Droop-Controlled Parallel Inverters in Microgrids

A New Reactive-Power Sharing Scheme for Two Inverter-Based Distributed Generations with Unequal Line Impedances in Islanded Microgrids

Secondary Voltage Control for Reactive Power Sharing in an Islanded Microgrid

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