scholarly journals Distributed Generation Control Using Modified PLL Based on Proportional-Resonant Controller

2020 ◽  
Vol 10 (24) ◽  
pp. 8891
Author(s):  
Ahmad Zare ◽  
Mazda Moattari ◽  
Rui Melicio
Keyword(s):  
Reactive Power ◽  
Frequency Measurement ◽  
Network Control ◽  
Power Sharing ◽  
Distributed Generations ◽  
Control Approach ◽  
Output Terminal ◽  
Allowable Range ◽  
Terminal Voltage ◽  
Electrical Demand

Due to the increasing necessity for electrical demand, the microgrids (MGs) based on distributed generations (DGs) within power electronic interfaces are being extended to improve the traditional network control. One of the common ways to achieve power sharing among the resources on an islanding MG is to use the droop control approach, performing based on proportional-integrator (PI) controllers. However, due to the effect of feeder impedance, obtaining the reactive power sharing using this method is not accurate and leads to overload in some DGs, resulting in the output terminal voltage of each DG going outside of the allowable range. The second problem arises when the frequency measurement is not performed precisely, leading to inaccurate active power sharing, which can be solved by using an improved phase locked loop (PLL). Therefore, the purpose of this paper is to propose an applicable and simple approach based on the use of conventional droop characteristics and a proportional-resonant (PR) controller in a DG control system. Due to the load changes in the microgrid and other contingencies, the proposed PLL-based controller is able to represent supreme performance with low error in several case studies.

scholarly journals A New Reactive-Power Sharing Scheme for Two Inverter-Based Distributed Generations with Unequal Line Impedances in Islanded Microgrids

Energies ◽  
2017 ◽  
Vol 10 (11) ◽  
pp. 1800 ◽  
Author(s):  
Jae-Hyuk Kim ◽  
Yoon-Seok Lee ◽  
Hyun-Jun Kim ◽  
Byung-Moon Han
Keyword(s):  
Reactive Power ◽  
Power Sharing ◽  
Distributed Generations ◽  
Sharing Scheme

scholarly journals An Optimal Control Scheme for Load Bus Voltage Regulation and Reactive Power-Sharing in an Islanded Microgrid

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6490
Author(s):  
Muhammad Zahid Khan ◽  
Chaoxu Mu ◽  
Salman Habib ◽  
Khurram Hashmi ◽  
Emad M. Ahmed ◽  
...  
Keyword(s):  
Optimal Control ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Communication Link ◽  
Control Approach ◽  
Control Scheme ◽  
Islanded Microgrid ◽  
Optimal Regulator ◽  
Optimal Control Scheme

This paper presents an optimal control scheme for an islanded microgrid (MG), which performs reactive power-sharing and voltage regulation. Two-fold objectives are achieved, i.e., the load estimation strategy, firstly, approximates the MG’s impedance and transmits this information through a communication link. Based on approximated impedance information, an optimal regulator is then constructed to send optimal control commands to respective local power controllers of each distributed generation unit. An optimal regulator is a constraints optimized problem, mainly responsible to restore the buses’ voltage magnitudes and realize power-sharing proportionally. The important aspect of this control approach is that the voltage magnitude information is only required to be transferred to each inverter’s controller. In parallel, a secondary control layer for frequency restoration is implemented to minimize the system frequency deviations. The MATLAB/Simulink and experimental results obtained under load disturbances show the effectiveness for optimizing the voltage and power. Modeling and analysis are also verified through stability analysis using system-wide mathematical small-signal models.

scholarly journals Droop Method Development for Microgrids Control Considering Higher Order Sliding Mode Control Approach and Feeder Impedance Variation

2021 ◽  
Vol 11 (3) ◽  
pp. 967
Author(s):  
Abdonaser Saleh-Ahmadi ◽  
Mazda Moattari ◽  
Amir Gahedi ◽  
Edris Pouresmaeil
Keyword(s):  
Sliding Mode Control ◽  
Method Development ◽  
Reactive Power ◽  
Sliding Mode ◽  
Power Sharing ◽  
Control Approach ◽  
Mode Control ◽  
Impedance Variation ◽  
Parallel Mode ◽  
The Stability

Due to the growing power demands in microgrids (MGs), the necessity for parallel production achieved from distributed generations (DGs) to supply the load required by customers has been increased. Since the DGs have to procure the demand in parallel mode, they are faced with several technical and economic challenges, such as preventing DGs overloading and not losing network stability considering feeder impedance variation. This paper presents a method that upgrades the droop controller based on sliding mode approach, so that DGs are able to prepare a suitable reactive power sharing without error even in more complex MGs. In the proposed strategy, the third-order sliding mode controller significantly reduces the V-Q error and increases the accuracy in adjusting the voltage at the DG output terminals. Various case studies conducted out in this paper validate the truthfulness of the proposed method, considering the stability analysis using Lyapunov function. Finally, by comparing the control parameters of the proposed technique with existing methods, the superiority, simplicity and effectiveness of the 3rd order sliding mode control (SMC) method are determined.

scholarly journals A Novel Adaptive Control Approach Based on Available Headroom of the VSC-HVDC for Enhancement of the AC Voltage Stability

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3222
Author(s):  
Duc Nguyen Huu
Keyword(s):  
Adaptive Control ◽  
Voltage Stability ◽  
Reactive Power ◽  
Control Method ◽  
Offshore Wind ◽  
Voltage Source ◽  
Long Distance ◽  
Control Approach ◽  
Hvdc System ◽  
Voltage Support

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.

A Communication-less Multi-mode Control Approach for Adaptive Power-Sharing in Ships-based Seaport Microgrid

2021 ◽  
pp. 1-1
Author(s):  
Muhammad Umair Mutarraf ◽  
Yacine Terriche ◽  
Mashood Nasir ◽  
Yajuan Guan ◽  
Chun-Lien Su ◽  
...  
Keyword(s):  
Power Sharing ◽  
Control Approach ◽  
Mode Control ◽  
Adaptive Power ◽  
Multi Mode
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