Droop Control Strategy Incorporating Coupling Compensation and Virtual Impedance for Microgrid Application

Peng, Zishun; Bi, Dongxue; Wen, Yumei; Dai, Yuxing; Yin, Xin; Shen, Z. John

doi:10.1109/tec.2019.2892621

Cited by 49 publications

(34 citation statements)

References 38 publications

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“…Then, R c i s are estimated from (8) and new droop parameters are obtained. By simplifying (11), the following equation is derived that shows how the droop parameter is changed according to the line resistances: (12) This equation shows that if the initial droop parameters are the same, each converter's droop parameter deviates from R d 1 according to the difference between the line resistances:…”

Section: B Voltage Sources With Unequal Load Sharingmentioning

confidence: 99%

“…The references in the literature review proposed some methods to suppress circulating currents. However, they need huge computational efforts and their design procedures are complex [12]. On the other hand, they focus on suppressing circulating currents for equal rating converters.…”

Section: B Voltage Sources With Unequal Load Sharingmentioning

confidence: 99%

“…It doesn't improve the current sharing among converters which is deteriorated by line resistances. In [12], a generic method of particle swarm optimization is introduced for tuning the virtual resistance of the droop controller. This method does not calculate line impedance and achieves the current sharing through heuristic methods.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Adaptive Droop Control Method for Suppressing Circulating Currents in DC Microgrids

Ghanbari

Bhattacharya

2020

IEEE Open J. Power Energy

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DC microgrids are introduced to reduce the conversion stages needed for connection of DC sources to the DC loads. They employ the droop control algorithm for managing the power flow from sources to the loads. However, the droop control functionality is affected by circuit parameters, especially line resistances. As a consequence, load sharing as the primary objective of the droop controller lacks accuracy. Parallel-connected converters have mismatched output voltages, resulting in circulating currents. This paper proposes an adaptive droop control algorithm for suppressing circulating currents in a low voltage DC microgrid. Line resistances are estimated through mathematical calculations and droop parameters are adjusted accordingly. Moreover, a distributed secondary controller is proposed to improve the load sharing accuracy and eliminate the effect of line resistances. The secondary controller shifts the droop controller voltage setpoint according to the converter current. Both of the proposed methods result in an accurate load sharing; Each of the participating converters has the rated current and consequently circulating current is suppressed. The effectiveness of the proposed method is verified through simulation and hardware-in-theloop (HIL) setup. INDEX TERMS Circulating current, dc microgrid, distributed control, droop control, hardware-in-the-loop (HIL).

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Section: B Voltage Sources With Unequal Load Sharingmentioning

confidence: 99%

Section: B Voltage Sources With Unequal Load Sharingmentioning

confidence: 99%

See 1 more Smart Citation

Adaptive Droop Control Method for Suppressing Circulating Currents in DC Microgrids

Ghanbari

Bhattacharya

2020

IEEE Open J. Power Energy

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“…The novel droop control proposed in [9] deploys virtual impedances and resolves the coupling effect and decreases the power circulation among DGs and stabilizes the MG. The complex virtual impedance was suggested in [10] to stabilize the voltage and to have a correct power sharing in island MG.…”

Section: Introductionmentioning

confidence: 99%

Virtual Impedances Optimization to Enhance Microgrid Small-Signal Stability and Reactive Power Sharing

et al. 2020

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Microgrid instability poses critical issues to the power delivery following a load change or a tripping event. In island operating mode lack of grid intensifies this challenge. This study aims at controlling several converter-based distributed generations (DG) sharing the power in an island microgrid (MG). At first, the microgrid model including virtual impedances and phase-locked loop (PLL) is introduced. Afterwards a novel small-signal stability analysis for island microgrids is proposed. Finally, an optimization algorithm based on particle swarm optimization (PSO) is proposed to design the virtual impedances. The optimization algorithm analyzes all possible operating points and aims at maximizing the microgrid stability index while keeping the reactive power mismatches at minimum level. The fractional objective function facilitates reaching at these objectives simultaneously. The proposed optimization algorithm is implemented in two separate case-studies and the corresponding virtual impedances are drawn in any microgrid. On the other hand, The voltage drops are checked as a condition in the optimization process. The results drawn from two separate case-studies verify that the proposed algorithm effectively maximizes the microgrid stability index and minimizes the reactive power mismatches.

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“…However, the above method did not consider the influence of line impedance on DG, nor did it consider the power allocation of the system. References [32], [33] used the improved particle swarm optimization to optimize the parameters of the droop control in real time, which effectively improved the power allocation accuracy of the microgrid. However, as a centralized control structure, the above methods not only increase the complexity of the system, but also place high requirement on the communication system.…”

Section: Introductionmentioning

confidence: 99%

An Adaptive Droop Control Strategy for Islanded Microgrid Based on Improved Particle Swarm Optimization

Zhang

Zheng

Su³

et al. 2020

IEEE Access

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In an islanded microgrid with multiple distributed generations (DGs), the difference in line impedance may cause local voltage deviation, which leads to a series of problems such as lower power allocation accuracy and bus voltage drop under traditional droop control. In this respect, a method for optimizing the droop control using an improved particle swarm optimization (IPSO) is proposed. Firstly, the microgrid structure and influence of line parameters on traditional droop control strategy is analyzed. Then, an improved particle swarm optimization is proposed. Based on the basic particle swarm optimization (PSO) algorithm, a fuzzy inference system (FIS) is introduced to dynamically adjust the particle swarm optimization, which can effectively improve the global search ability and local search ability of the algorithm. After that, the improved algorithm is applied to the droop controller, simultaneously, the range of stable operation of the system is determined by small signal analysis. Finally, the simulation and experiment results show that the proposed improved droop control strategy can achieve accurate allocation of active and reactive power effectively while maintaining bus voltage and system frequency stability, enhance the dynamic performance and transient stability of the microgrid system.

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Droop Control Strategy Incorporating Coupling Compensation and Virtual Impedance for Microgrid Application

Cited by 49 publications

References 38 publications

Adaptive Droop Control Method for Suppressing Circulating Currents in DC Microgrids

Adaptive Droop Control Method for Suppressing Circulating Currents in DC Microgrids

Virtual Impedances Optimization to Enhance Microgrid Small-Signal Stability and Reactive Power Sharing

An Adaptive Droop Control Strategy for Islanded Microgrid Based on Improved Particle Swarm Optimization

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