scholarly journals A new power sharing control method for an autonomous microgrid with regard to the system stability

Automatika ◽  
2018 ◽  
Vol 59 (1) ◽  
pp. 87-93 ◽  
Author(s):  
A. Khaledian ◽  
M. Aliakbar Golkar
Keyword(s):  
Control Method ◽  
Power Sharing ◽  
System Stability

scholarly journals Fuzzy-Based Distributed Cooperative Secondary Control with Stability Analysis for Microgrids

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 399
Author(s):  
Mahmuda Begum ◽  
Mohsen Eskandari ◽  
Mohammad Abuhilaleh ◽  
Li Li ◽  
Jianguo Zhu
Keyword(s):  
Control System ◽  
Stability Analysis ◽  
Cooperative Control ◽  
Dynamic Behaviour ◽  
Reactive Power ◽  
Control Method ◽  
Power Sharing ◽  
System Stability ◽  
Control Technique ◽  
Secondary Control

This research suggests a novel distributed cooperative control methodology for a secondary controller in islanded microgrids (MGs). The proposed control technique not only brings back the frequency/voltage to its reference values, but also maintains precise active and reactive power-sharing among distributed generation (DG) units by means of a sparse communication system. Due to the dynamic behaviour of distributed secondary control (DSC), stability issues are a great concern for a networked MG. To address this issue, the stability analysis is undertaken systematically, utilizing the small-signal state-space linearized model of considering DSC loops and parameters. As the dynamic behaviour of DSC creates new oscillatory modes, an intelligent fuzzy logic-based parameter-tuner is proposed for enhancing the system stability. Accurate tuning of the DSC parameters can develop the functioning of the control system, which increases MG stability to a greater extent. Moreover, the performance of the offered control method is proved by conducting a widespread simulation considering several case scenarios in MATLAB/Simscape platform. The proposed control method addresses the dynamic nature of the MG by supporting the plug-and-play functionality, and working even in fault conditions. Finally, the convergence and comparison study of the offered control system is shown.

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 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.

Control Strategy of Wind Photovoltaic and Energy Storage System Stability Running

2013 ◽  
Vol 336-338 ◽  
pp. 547-550
Author(s):  
Ji Hong Zhang ◽  
Zhen Kui Wu ◽  
Hua Li ◽  
Han Shan Li
Keyword(s):  
Energy Storage ◽  
Distributed Generation ◽  
Control Strategy ◽  
Control Method ◽  
Storage System ◽  
Energy Storage System ◽  
System Stability ◽  
Mathematics Model ◽  
Generation Efficiency ◽  
Micro Grid

Micro grid may exert adequately distributed generation efficiency, and that wind Photovoltaic and Energy Storage is a key equipment in the micro grid. Aiming at the distributed generation existing intermittence and randomicity characteristic, the paper discussed the micro grid P/Q control method under the connection grid state and the micro grid U/F control method under the disconnection grid state. It also studied the distributed generation parameters variational law under the micro grid different run mode, and built the correlative mathematics model and tested by simulation. The results show: the control strategy ensured the mice grid running stably, and achieved the system anticipative design request, and offered theory foundation for the distributed generation extend application.

scholarly journals New adaptive droop control with combined line impedance estimation method for parallel inverters

2016 ◽  
Vol 19 (4) ◽  
pp. 45-64
Author(s):  
Phuong Minh Le ◽  
Duy Vo Duc Hoang ◽  
Hoa Thi Xuan Pham ◽  
Huy Minh Nguyen
Keyword(s):  
Kalman Filter ◽  
Control Method ◽  
Least Squares Method ◽  
Estimation Method ◽  
Load Sharing ◽  
Phase Lock Loop ◽  
Power Sharing ◽  
Voltage Source ◽  
Droop Control ◽  
Voltage Source Inverters

This paper presents a new load sharing control between paralleled three-phase inverters in an islanded-microgrid based on the line impedance estimation online by the use of the Kalman filter. We can solve the mismatch of power sharing when the line impedance changes due to the temperature and frequency, significant differences of line parameters and requirements of Plug-and-Play mode of inverters connected to the microgrid. Moreover, the paper also presents a new Droop control method working with the line impedance which is different from the Droop traditional algorithm when the line impedance is assumed pure resistance R or pure inductance X. In the paper, the line impedance estimation for parallel inverters uses the least squares method combined with Kalman filter. In addition, secondary control loops are designed to restore the voltage amplitude and frequency of the microgrid by using a combined nominal value SOGI-PLL with generalized integral block and phase lock loop to exactly monitor the voltage magnitude and frequency phase at common PCC. Control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of the power sharing. The simulation results have shown the accuracy of the proposed control method. Therefore, the proposed adaptive droop control method based on line impedance estimation can be an alternative one for load sharing control in islanded microgrids.

Position and Attitude Control of Underactuated Drones Using the Adaptive Function Approximation Technique

2020 ◽  
Author(s):  
Azin Shamshirgaran ◽  
Donald Ebeigbe ◽  
Dan Simon
Keyword(s):  
Disturbance Rejection ◽  
Function Approximation ◽  
Control Method ◽  
System Stability ◽  
Linear Feedback ◽  
Approximation Technique ◽  
Adaptive Function ◽  
Edge Tracking ◽  
Highly Nonlinear ◽  
Function Approximation Technique

Abstract Despite the popularity of drones and their relatively simple operation, the underlying control algorithms can be difficult to design due to the drones’ underactuation and highly nonlinear properties. This paper focuses on position and orientation control of drones to address challenges such as path and edge tracking, and disturbance rejection. The adaptive function approximation technique control method is used to control an underactuated and nonlinear drone. The controller utilizes reference attitude signals, that are derived from a proportional derivative (PD) linear feedback control methodology. To avoid analytic expressions for the reference attitude velocities, we employ a continuous-time Kalman filter based on a model of the measurement signal — which is derived by passing the reference attitude position through a low-pass signal differentiator — as a second-order Newtonian system. Stability of the closed loop system is proven using a Lyapunov function. Our design methodology simplifies the control process by requiring only a few tuning variables, while being robust to time-varying and time-invariant uncertainties with unknown variation bounds, and avoids the requirement for the knowledge of the dynamic equation that governs the attitude of the drone. Three different scenarios are simulated and our control method shows better accuracy than the proportional-derivative controller in terms of edge tracking and disturbance rejection.

scholarly journals Secondary Control for Storage Power Converters in Isolated Nanogrids to Allow Peer-to-Peer Power Sharing

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 140 ◽  
Author(s):  
Eva González-Romera ◽  
Enrique Romero-Cadaval ◽  
Carlos Roncero-Clemente ◽  
Mercedes Ruiz-Cortés ◽  
Fermín Barrero-González ◽  
...  
Keyword(s):  
Power Flow ◽  
Control Method ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Power Converter ◽  
Power Sharing ◽  
Primary Control ◽  
Secondary Control ◽  
Control Loops ◽  
Energy Interchange

It is usual in literature that power sharing among grid-forming sources of an isolated microgrid obeys their energy rating, instead of economic agreements between stakeholders, and circulating energy among them is usually avoided. However, these energy interchanges make strong sense and classical power sharing methods must be reformulated in the context of prosumer-based microgrids. This paper proposes a secondary control method for a prosumer-based low-voltage nanogrid that allows for energy interchange between prosumers, where storage systems, together with PV generators, are the controllable grid-forming sources. A power flow technique adapted to islanded microgrids is used for secondary control algorithm and the whole hierarchical control strategy for the prosumer converter is simulated and validated. This hierarchical control consists of three stages: tertiary control plans the energy interchange among prosumers, secondary obtains different voltage and power setpoints for each of the grid-forming sources, and, finally, primary control guarantees stable voltage and frequency values within the nanogrid with droop rules. Inner control loops for the power converter are also defined to track setpoints and assure stable performance. Simulation tests are carried out, which prove the stability of the proposed methods and the accuracy of the setpoint tracking.

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