Feasible Range and Optimal Value of the Virtual Impedance for Droop-Based Control of Microgrids

Wu, Xiangyu; Shen, Chen; Iravani, Reza

doi:10.1109/tsg.2016.2519454

Cited by 119 publications

(93 citation statements)

References 21 publications

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“…Considering the pulse-width modulation (PWM) and the sampling process, the control diagram is shown in Figure 4. To satisfy the decoupling condition of the d,q axis, "virtual impedance" is introduced in low-voltage AC MG [25,26]. After decoupling, structure of the q axis is chosen to analyze because d,q share the same structure.…”

Section: Pq Control Methodsmentioning

confidence: 99%

“…Furthermore, it can be considered that ∆V * 0q ≈ E∆θ because changes of E * are much smaller than that of θ, where E is the reference voltage before reactive droop loop. The control structure is shown in Figure 7 [26].…”

Section: Inductive Droop Controlmentioning

confidence: 99%

“…Furthermore, it can be considered that ΔV * 0q ≈ EΔθ because changes of E * are much smaller than that of θ, where E is the reference voltage before reactive droop loop. The control structure is shown in Figure 7 [26]. After reasonable setting of virtual impedance, it is equivalent that the previous line impedance connects in series with a reactance Xv, which satisfies the following relationship Xv + Xv >> Rl, and then Rl in Ha and Hb can be neglected, that is Hb = 0, indicating the realization of decoupling in droop control.…”

Section: Inductive Droop Controlmentioning

confidence: 99%

See 2 more Smart Citations

Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

Liang¹,

Yue²,

Huang³

et al. 2018

Energies

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Abstract:The stable operation of a microgrid is crucial to the integration of renewable energy sources. However, with the expansion of scale in electronic devices applied in the microgrid, the interaction between voltage source converters poses a great threat to system stability. In this paper, the model of a three-source microgrid with a multi master-slave control method in islanded mode is built first of all. Two sources out of three use droop control as the main control source, and another is a subordinate one with constant power control which is also known as real and reactive power (PQ) control. Then, the small signal decoupling control model and its stability discriminant equation are established combined with "virtual impedance". To delve deeper into the interaction between converters, mutual influence of paralleled converters of two main control micro sources and their effect on system stability is explored from the perspective of control parameters. Finally, simulation and analysis are launched and the study serves as a reference for parameter setting of converters in a microgrid.

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Section: Pq Control Methodsmentioning

confidence: 99%

Section: Inductive Droop Controlmentioning

confidence: 99%

Section: Inductive Droop Controlmentioning

confidence: 99%

See 1 more Smart Citation

Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

Liang¹,

Yue²,

Huang³

et al. 2018

Energies

View full text Add to dashboard Cite

show abstract

“…Then, the droop controller realizes the CFR/CVAR-based improved P/U droop control and sends "order voltage" v r to a virtual controller. Generally, in a virtual controller, one must subtract the virtual voltage drop from the "order voltage" to realize virtual impedance [30,31] and then obtain a new "order voltage" v. In the inter-loop controller, robust control is used to realize that capacitor voltage tracks a new "order voltage" with minimum robustness problem in case of load variations. Pulse width modulation (PWM) mode modulates the waveform of the inverter voltage.…”

Section: Control System Of Improved Droop-controlled Invertermentioning

confidence: 99%

An Improved Droop Control Strategy Based on Changeable Reference in Low-Voltage Microgrids

et al. 2017

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This paper proposes an improved droop control strategy based on changeable reference in low-voltage microgrids. To restore running frequency of distributed generation to a rated value without affecting its reactive power output, changeable frequency reference, mainly compensating for frequency deviation, are proposed corresponding to various load demands. In terms of active power sharing inaccuracy associated with mismatched line impedance, changeable voltage amplitude reference is proposed to obtain a droop line suitable for the actual voltage of distributed generations. By further improvement of the active droop coefficient, power sharing is accurate with a difference in actual voltages of distributed generations. Virtual negative inductance is used to neutralize the redundant line inductance for strictly improving sharing accuracy. A robust control method based on Lyapunov function is used to handle the robustness problem in case of load variation. The control scheme is entirely decentralized, so communication links among distributed generations are redundant. Finally, simulation studies demonstrate the effectiveness of a control strategy.

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“…The second category is the virtual impedance-based decoupling control [14][15][16][17][18]. Through introducing a virtual inductance and subtracting its voltage drop at the input side of the voltage loop, the system impedance can be adjusted for power decoupling.…”

Section: Introductionmentioning

confidence: 99%

Power Decoupling Method Based on the Diagonal Compensating Matrix for VSG-Controlled Parallel Inverters in the Microgrid

Zhou

2017

Energies

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Abstract:The thought of the virtual synchronous generator (VSG) for controlling the grid-connected inverters and providing virtual inertia to the microgrid is emerging as a wide extension of the droop control, power coupling that always exists in the low-voltage microgrid, which may deteriorate the dynamic response and the stability of the system. In this paper, the principle of VSG control is introduced first. As an important issue of VSG control, the mechanism of the power coupling in the low-voltage microgrid is analyzed and the small-signal equivalent model of the power transmission loop is established. Subsequently, a power decoupling method based on the diagonal compensating matrix for VSG is proposed, which can realize the power decoupling with no impact on the original control channel. Meanwhile, the feasibility analysis of the decoupling method and the improved approach for reactive power sharing are also discussed. Simulation results verify the effectiveness of the decoupling strategy for VSGs.

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Feasible Range and Optimal Value of the Virtual Impedance for Droop-Based Control of Microgrids

Cited by 119 publications

References 21 publications

Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

An Improved Droop Control Strategy Based on Changeable Reference in Low-Voltage Microgrids

Power Decoupling Method Based on the Diagonal Compensating Matrix for VSG-Controlled Parallel Inverters in the Microgrid

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