scholarly journals A Centralized Shifted Voltage Control Method for Accurate Power Sharing in DC Islanded Microgrids

2021 ◽  
Vol 19 ◽  
pp. 155-159
Author(s):  
Minh-Duc Pham ◽  
◽  
Hong-Hee Lee
Keyword(s):  
Output Voltage ◽  
Control Method ◽  
Voltage Drop ◽  
Renewable Energy Sources ◽  
Control Variable ◽  
Voltage Control ◽  
Power Sharing ◽  
System Stability ◽  
Small Scale ◽  
Dc Microgrid

Due to line impedance mismatch among renewable energy sources (RESs), it is hard to realize accurate power sharing in the DC microgrid system. To solve this issue, a distributed power sharing strategy for adjusting the RES output voltage is developed by adding shifted output voltage into each local controller. Thanks to the shifted voltage, the influence of voltage drop caused by the droop controller is effectively mitigated, so that the DC bus voltage is constantly balanced regardless of the load changes. The proposed method is realized with a centralized approach, and all the required control variable to determine the reference voltage is transmitted through low-bandwidth communication. The controller design and system stability are analyzed in detail with a simplified microgrid model. Small-scale DC microgrid is simulated to verify the effectiveness of the centralized shifted voltage control method.

scholarly journals A Novel VSG-Based Accurate Voltage Control and Reactive Power Sharing Method for Islanded Microgrids

2019 ◽  
Vol 11 (23) ◽  
pp. 6666 ◽  
Author(s):  
Bowen Zhou ◽  
Lei Meng ◽  
Dongsheng Yang ◽  
Zhanchao Ma ◽  
Guoyi Xu
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Low Voltage ◽  
Voltage Drop ◽  
Reference Value ◽  
Voltage Control ◽  
Synchronous Generator ◽  
Stability Control ◽  
Control Area ◽  
Power Sharing

Islanded microgrids (IMGs) are more likely to be perturbed by renewable generation and load demand fluctuation, thus leading to system instability. The virtual synchronous generator (VSG) control has become a promising method in the microgrids stability control area for its inertia-support capability. However, the improper power sharing and inaccurate voltage control problems of the distributed generations (DGs) in microgrids still has not been solved with a unified method. This paper proposes a novel VSG equivalent control method named Imitation Excitation Control (IEC). In this method, a multi-objective control strategy for voltage and reactive power in a low voltage grid that considers a non-negligible resistance to reactance ratio (R/X) is proposed. With the IEC method, the voltage drop across feeders is compensated, thus the terminal voltage of each inverter will be regulated, which will effectively stabilize the PCC (point of common coupling) voltage and inhibit the circular current. Meanwhile, this method can realize accurate reactive power tracking the reference value, making it accessible for reactive power scheduling. What is more, the reasonability of the IEC model, namely the equivalent mechanical characteristic and transient process inertia support between VSGs and conventional synchronous generators (SG), is illustrated in this paper. Moreover, steady-state stability is proved by the small-signal modeling method, and the energy required by inertia support is given. Finally, the simulation result validates the effectiveness of the proposed method, and it is also demonstrated that the proposed method outperforms the conventional droop control method.

scholarly journals Distributed Adaptive Virtual Impedance for Reactive Power Sharing in Microgrid

2020 ◽  
pp. 135-140
Author(s):  
Harini M and Dr.S.Chitra
Keyword(s):  
Power Quality ◽  
Reactive Power ◽  
Control Method ◽  
Impedance Control ◽  
Renewable Energy Sources ◽  
Power Sharing ◽  
System Stability ◽  
Environment Simulation ◽  
Control Stability ◽  
Virtual Impedance

The concept of microgrid has been developed to realize flexible coordination control among Distributed Generation (DG) units, improve the power quality supplied to customers. The problem such as the power quality and the system stability due to the intermittency of the renewable energy sources and the fluctuating load profile. The reactive power sharing done by droop control method but reactive power is not accurately shared if there is a local load at each DG. In this paper adaptive virtual impedance control is used to improve the power control stability and sharing performance of real and reactive power sharing is compared by using MATLAB/Simulink environment. Simulation results shows the effectiveness of the proposed method is achieving load reactive power sharing and the voltage restoration is settles in less time.

Output voltage control method of PWM-controlled cycloconverters with space vectors

1991 ◽  
Vol 111 (5) ◽  
pp. 117-126 ◽  
Author(s):  
Akio Ishiguro ◽  
Takeshi Furuhashi ◽  
Shigeru Okuma ◽  
Yoshiki Uchikawa ◽  
Muneaki Ishida
Keyword(s):  
Output Voltage ◽  
Control Method ◽  
Voltage Control ◽  
Space Vectors

Small-Scale Permanent Magnet Synchronous Wind Power System Control Method Research and Simulation Analysis

2011 ◽  
Vol 347-353 ◽  
pp. 3555-3558
Author(s):  
Peng Zhao ◽  
Wen Yi Li ◽  
Xuan He ◽  
Xin Yao ◽  
Yin Sha Wang ◽  
...  
Keyword(s):  
Vector Control ◽  
Permanent Magnet ◽  
Output Voltage ◽  
Control Method ◽  
Simulation Analysis ◽  
Model Simulation ◽  
Permanent Magnet Synchronous Motor ◽  
Small Scale ◽  
System Control ◽  
Power System Control

Aims at the small wind generations output voltage fluctuation problems, according to the characteristics of permanent magnet synchronous generator, by the vector control methods, in MATLAB/Simulink lans established permanent magnet synchronous motor current speed 2-ring vector control simulation model. Simulation results show that, the method can improve the small wind turbine output voltage stability.

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

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2223 ◽  
Author(s):  
Haifeng Liang ◽  
Yue Dong ◽  
Yuxi Huang ◽  
Can Zheng ◽  
Peng Li
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Mutual Influence ◽  
Renewable Energy Sources ◽  
System Stability ◽  
Voltage Source ◽  
Stable Operation ◽  
Parameter Configuration ◽  
Islanded Mode ◽  
Virtual Impedance

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.

A Perspective on Energy Storage and Other Means to Integrate Increasing Shares of Renewable Electricity Generation

Green ◽  
2014 ◽  
Vol 4 (1-6) ◽  
Author(s):  
Arndt Neuhaus ◽  
Frank-Detlef Drake ◽  
Gunnar Hoffmann ◽  
Friedrich Schulte
Keyword(s):  
Energy Storage ◽  
Power Plants ◽  
Large Scale ◽  
Distributed Storage ◽  
Renewable Energy Sources ◽  
Energy Transition ◽  
System Stability ◽  
Small Scale ◽  
Specific Class ◽  
High Level

AbstractThe transition to a sustainable electricity supply from renewable energy sources (RES) imposes major technical and economic challenges upon market players and the legislator. In particular the rapid growth of volatile wind power and photovoltaic generation requires a high level of flexibility of the entire electricity system, therefore major investments in infrastructures are needed to maintain system stability. This raises the important question about the role that central large-scale energy storage and/or small-scale distributed storage (“energy storage at home”) are going to play in the energy transition. Economic analyses show that the importance of energy storage is going to be rather limited in the medium term. Especially competing options like intelligent grid extension and flexible operation of power plants are expected to remain favourable. Nonetheless additional storage capacities are required if the share of RES substantially exceeds 50% in the long term. Due to the fundamental significance of energy storages, R&D considers a broad variety of types each suitable for a specific class of application.

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