Decentralized Voltage Balancing and Power Sharing in Islanded Bipolar DC Microgrids

2020 ◽  
Author(s):  
Saman Dadjo Tavakoli
Keyword(s):  
Transfer Functions ◽  
Control Method ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Dc Microgrid ◽  
Voltage Balancing ◽  
Dc Microgrids ◽  
Converter Topology ◽  
Unbalanced Loads

<div>This paper presents a decentralized control scheme for voltage balancing and power sharing in bipolar dc</div><div>microgrids. This relies on utilizing a converter topology which offers three levels of output voltage availability with the key features of boosting the input voltage and balancing the output voltages. This converter makes it possible to further improve the structure of bipolar dc microgrids as it does not require a central voltage balancer. Small-signal analysis is done and system transfer functions are derived. Based on the RGA concept the highly coupled input-output pairs are found which helps with replacing the MIMO control system of the converter by two SISO systems. The appropriate voltage and current controllers are designed based on SISO principles. Moreover, a double droop control method is proposed which fulfills the simultaneous power sharing and voltage regulation of DG units in the host microgrid. The effectiveness of the proposed control strategy is demonstrated through simulation studies conducted on an</div><div>islanded bipolar dc microgrid involving unbalanced loads, while the voltage balancing of the bipolar dc microgrid and the power sharing accuracy are evaluated.</div>

scholarly journals Decentralized Voltage Balancing and Power Sharing in Islanded Bipolar DC Microgrids

2020 ◽  
Author(s):  
Saman Dadjo Tavakoli
Keyword(s):  
Transfer Functions ◽  
Control Method ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Dc Microgrid ◽  
Voltage Balancing ◽  
Dc Microgrids ◽  
Converter Topology ◽  
Unbalanced Loads

<div>This paper presents a decentralized control scheme for voltage balancing and power sharing in bipolar dc</div><div>microgrids. This relies on utilizing a converter topology which offers three levels of output voltage availability with the key features of boosting the input voltage and balancing the output voltages. This converter makes it possible to further improve the structure of bipolar dc microgrids as it does not require a central voltage balancer. Small-signal analysis is done and system transfer functions are derived. Based on the RGA concept the highly coupled input-output pairs are found which helps with replacing the MIMO control system of the converter by two SISO systems. The appropriate voltage and current controllers are designed based on SISO principles. Moreover, a double droop control method is proposed which fulfills the simultaneous power sharing and voltage regulation of DG units in the host microgrid. The effectiveness of the proposed control strategy is demonstrated through simulation studies conducted on an</div><div>islanded bipolar dc microgrid involving unbalanced loads, while the voltage balancing of the bipolar dc microgrid and the power sharing accuracy are evaluated.</div>

scholarly journals Matlab based simulation model of standalone DC Microgrid for Remote Area Power Applications

2018 ◽  
Vol 7 (1.8) ◽  
pp. 153 ◽  
Author(s):  
G Srinivasa Rao ◽  
K Harinadha Reddy ◽  
B Ravi Teja ◽  
B Devasahayam ◽  
Shaik Khaleel
Keyword(s):  
Control Method ◽  
High Reliability ◽  
Voltage Regulation ◽  
Remote Area ◽  
Operating Conditions ◽  
Power Sharing ◽  
Renewable Energy Resources ◽  
Grid Data ◽  
Energy Management Strategy ◽  
Dc Microgrid

DC microgrids are playing an important role in remote area power applications like power supply to off-grid tele communication towers, off-grid data centres, rural electrification etc. and moreover these are extensively used, as these appear as solutions for integrating two or more renewable energy resources. In this paper, photovoltaic (PV) and wind energy systems have been integrated along with batteries and a load to form an autonomous DC microgrid with high reliability and stability.  The primary aspects which are to be taken into consideration in a standalone DC microgrid are voltage regulation, load sharing and battery management. In this paper, an energy management strategy is proposed which includes maximum power point tracking (MPPT) algorithms and voltage droop control method. This strategy ensures optimal power sharing among the sources and increases reliability and stability profile of the microgrid. The operation of the microgrid in different modes and the behaviour of the system at different operating conditions is studied by varying the solar irradiance and wind speed for specific time periods. The simulation is done in Matlab Simulink software and the results are obtained. 

scholarly journals Structural Improvements in Consensus-Based Cooperative Control of DC Microgrids

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 187 ◽  
Author(s):  
Muhammad Adnan Mumtaz ◽  
Muhammad Mansoor khan ◽  
Xiangzhong Fang ◽  
Muhammad Umair Shahid ◽  
Muhammad Talib Faiz
Keyword(s):  
Cooperative Control ◽  
Voltage Regulation ◽  
Current Control ◽  
Power Sharing ◽  
System Stability ◽  
Control Loop ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
The Stability ◽  
Finite Gain

This study is dedicated to establishing a comparative analysis of the performance ofdifferent local controllers on the cooperative control of DC microgrids. One of the elementary andchallenging issues in DC microgrids is the assurance of fairness in proportional current sharingwhile accomplishing voltage regulation in parallelly connected distributed energy sources. In thiswork, structural improvements are proposed to enhance the system stability and controlperformance. A finite-gain controller was employed in the outer voltage control loop with a simpleproportional (P) controller in the inner current control loop of a converter. Due to the finite-gaincontroller, droop-like power sharing was achieved without droop coefficient. In order to furtherenhance the power-sharing accuracy and DC voltage regulation, a different method was adopted inconsensus-based cooperative control to estimate the average current and average voltage difference.Moreover, small signal analysis was used to scrutinize the stability and control performance of thelocal controller, while different communication delays and current disturbances were applied toexamine the performance of the controller. Finally, a four-node-based DC microgrid setup wasdeveloped in MATLAB/Simulink environment, and simulation results of the proposed and existingtechniques were scrutinized. The simulations results demonstrated the effectiveness of the proposedcontroller.

scholarly journals Robust Control Method for DC Microgrids and Energy Routers to Improve Voltage Stability in Energy Internet

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1622 ◽  
Author(s):  
Haochen Hua ◽  
Yuchao Qin ◽  
Hanxuan Xu ◽  
Chuantong Hao ◽  
Junwei Cao
Keyword(s):  
Power Transmission ◽  
Control Method ◽  
Voltage Regulation ◽  
Normal Operation ◽  
Local Network ◽  
Linear Matrix ◽  
Dc Microgrid ◽  
Voltage Stabilization ◽  
Energy Internet ◽  
Bus Voltage

The energy internet (EI) is a wide area power network that efficiently combines new energy technology and information technology, resulting in bidirectional on-demand power transmission and rational utilization of distributed energy resources (DERs). Since the stability of local network is a prerequisite for the normal operation of the entire EI, the direct current (DC) bus voltage stabilization for each individual DC microgrid (MG) is a core issue. In this paper, the dynamics of the EI system is modeled with a continuous stochastic system, which simultaneously considers related time-varying delays and norm-bounded modeling uncertainty. Meanwhile, the voltage stabilization issue is converted into a robust H ∞ control problem solved via a linear matrix inequality approach. To avoid the situation of over-control, constraints are set in controllers. The problem of finding a balance between voltage regulation performance and constraints for the controllers was also extensively investigated. Finally, the efficacy of the proposed methods is evaluated with numerical simulations.

A unified control strategy for power sharing and voltage balancing in bipolar DC microgrids

2017 ◽  
Vol 11 ◽  
pp. 58-68 ◽  
Author(s):  
Saman Dadjo Tavakoli ◽  
Mohammad Mahdavyfakhr ◽  
Mohsen Hamzeh ◽  
Keyhan Sheshyekani ◽  
Ebrahim Afjei
Keyword(s):  
Control Strategy ◽  
Power Sharing ◽  
Voltage Balancing ◽  
Dc Microgrids

scholarly journals Equivalent Sliding Mode Controller for Stability of DC Microgrid

2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Muhammad Rashad ◽  
Uzair Raoof ◽  
Nazam Siddique ◽  
Bilal Ashfaq Ahmed
Keyword(s):  
Reactive Power ◽  
Sliding Mode ◽  
Voltage Regulation ◽  
Pi Controller ◽  
Operating Conditions ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
Central Controller ◽  
The Stability ◽  
Decentralized Architecture

DC microgrids are gaining popularity due to their lack of reactive power compensation, frequency synchronization, and skin effect problems. However, DC microgrids are not exempted from stability issues. The stability of DC microgrids based on decentralized architecture is presented in this paper. Centralized architecture can degrade system performance and reliability due to the failure of a single central controller. Droop with proportional integral (PI) controller based on decentralized architecture is being used for DC microgrid stability. However, droop control requires a tradeoff between voltage regulation and droop gain. Further, global stability through PI controller cannot be verified and controller parameters cannot be optimized with different operating conditions. To address limitations, an equivalent sliding mode (SM) controller is proposed for a DC microgrid system in this paper. Detailed simulations are carried out, and results are presented, which show the effectiveness of an equivalent SM controller.

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