scholarly journals Triple‐harmonic‐droop control strategy for accurate harmonic power sharing in low‐voltage islanded microgrids

2021 ◽  
Author(s):  
Ebrahim Alizadeh ◽  
Aliakbar Motie Birjandi ◽  
Mohsen Hamzeh
Keyword(s):  
Control Strategy ◽  
Low Voltage ◽  
Power Sharing ◽  
Droop Control ◽  
Harmonic Power

A Droop Control Strategy with Impedance Compensation for Low Voltage Microgrid

2013 ◽  
Vol 441 ◽  
pp. 245-248
Author(s):  
Zhi Yong Yu ◽  
Ming Lu ◽  
Zhen Nan Wang ◽  
Yi Gong Zhang
Keyword(s):  
Control Strategy ◽  
Low Voltage ◽  
Power Sharing ◽  
Droop Control ◽  
Parallel Operation ◽  
Distributed Generations ◽  
Point Of Common Coupling ◽  
Simulation Results ◽  
Common Coupling ◽  
Virtual Impedance

With conventional droop control, parallel operation of distributed generations (DG) in microgrid would lead to unbalanced power sharing. In this paper, inherent limitation of conventional droop control is analyzed. Analysis results show that different converter output impedance and line impedance make the power sharing unbalanced. In order to weaken or eliminate impedance difference from point of common coupling (PCC) to DGs, virtual impedance is introduced. By the introduction of designed virtual impedance, a novel droop control strategy with impedance compensation is proposed in this paper. Simulation results are presented from a two converters parallel-connected microgrid, showing the effectiveness of the droop control with impedance compensation. Simulation results show that DGs with proposed approach can allocate the power equally, and work stably in grid-connected mode, island mode and progress of reconnection to grid.

scholarly journals A Novel Power Sharing Strategy Based on Virtual Flux Droop and Model Predictive Control for Islanded Low-Voltage AC Microgrids

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4893
Author(s):  
Saheb Khanabdal ◽  
Mahdi Banejad ◽  
Frede Blaabjerg ◽  
Nasser Hosseinzadeh
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Strategy ◽  
Low Voltage ◽  
Simulation Analysis ◽  
Power Sharing ◽  
Droop Control ◽  
Software Environment ◽  
Microgrid Control ◽  
Virtual Flux

The droop control scheme based on Q − ⍵ and P − V characteristics is conventionally employed to share the load power among sources in an islanded low-voltage microgrid with resistive line impedances. However, it suffers from poor active power sharing, and is vulnerable to sustained deviations in frequency and voltage. Therefore, accurate power sharing and maintaining the frequency and voltage in the desired ranges are challenging. This paper proposes a novel microgrid control strategy to address these issues. The proposed strategy consists of a virtual flux droop and a model predictive control, in which the virtual flux is the time integral of the voltage. Firstly, the novel virtual flux droop control is proposed to accurately control the power sharing among DGs. Then, the model predictive flux control is employed to generate the appropriate switching signals. The proposed strategy is simple without needing multiple feedback control loops. In addition, pulse width modulation is not required and tuning challenges for PI regulators are avoided. In order to evaluate the effectiveness of the proposed microgrid control strategy, simulation analysis is carried out in Matlab/Simulink software environment. The results show that accurate power sharing is achieved while a good dynamic response is provided. Furthermore, the voltage and frequency deviations are significantly improved.

scholarly journals Reactive power sharing in microgrid using virtual voltage

2021 ◽  
Vol 11 (4) ◽  
pp. 2743
Author(s):  
Eder A. Molina-Viloria ◽  
John E. Candelo Becerra ◽  
Fredy E. Hoyos Velasco
Keyword(s):  
Power Control ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Active Power ◽  
Power Sharing ◽  
Droop Control ◽  
Matlab Simulink ◽  
Distributed Generators ◽  
Additional Coefficient

The traditional droop control strategy has been applied previously in microgrids (MGs) to share accurately the active power. However, in some cases the result obtained when sharing reactive power is not the best, because of the parameters related to the distances from distributed generators (DGs) to the loads and the power variations. Therefore, this paper proposes a reactive power control strategy for a low voltage MG, where the unequal impedance related to the distances between generators and loads requires adjustments to work with the conventional frequency and voltage droop methods. Thus, an additional coefficient is calculated from parameters of the network that relate the location of elements. The test is perfomed by simulations in the MATLAB-Simulink software, considering a three-node MG with three DGs and a load that can change power at different periods of time. The results show that it is possible to improve reactive power sharing between the DGs located in the MG according to the load changes simulated and to improve voltages with this method.

scholarly journals A Novel Hierarchical Control Strategy for Low-Voltage Islanded Microgrids Based on the Concept of Cyber Physical System

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1835 ◽  
Author(s):  
Qiuxia Yang ◽  
Dongmei Yuan ◽  
Xiaoqiang Guo ◽  
Bo Zhang ◽  
Cheng Zhi
Keyword(s):  
Control Strategy ◽  
Physical System ◽  
Reactive Power ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Physical Layer ◽  
Cyber Physical System ◽  
Droop Control ◽  
Control Effect ◽  
Consensus Control

Based on the concept of cyber physical system (CPS), a novel hierarchical control strategy for islanded microgrids is proposed in this paper. The control structure consists of physical and cyber layers. It’s used to improve the control effect on the output voltages and frequency by droop control of distributed energy resources (DERs), share the reactive power among DERs more reasonably and solve the problem of circumfluence in microgrids. The specific designs are as follows: to improve the control effect on voltages and frequency of DERs, an event-trigger mechanism is designed in the physical layer. When the trigger conditions in the mechanism aren’t met, only the droop control (i.e., primary control) is used in the controlled system. Otherwise, a virtual leader-following consensus control method is used in the cyber layer to accomplish the secondary control on DERs; to share the reactive power reasonably, a method of double virtual impedance is designed in the physical layer to adjust the output reactive power of DERs; to suppress circumfluence, a method combined with consensus control without leader and sliding mode control (SMC) is used in the cyber layer. Finally, the effectiveness of the proposed hierarchical control strategy is confirmed by simulation results.

scholarly journals An Improved Droop Control Strategy for Reactive Power Sharing in Islanded Microgrid

2015 ◽  
Vol 30 (6) ◽  
pp. 3133-3141 ◽  
Author(s):  
Hua Han ◽  
Yao Liu ◽  
Yao Sun ◽  
Mei Su ◽  
Josep M. Guerrero
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Power Sharing ◽  
Droop Control ◽  
Islanded Microgrid
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