scholarly journals Analysis and design of new droop control scheme for three-phase parallel inverters in standelone Microgrid.

2016 ◽  
Vol 19 (1) ◽  
pp. 5-19
Author(s):  
Phuong Minh Le ◽  
Huy Minh Nguyen ◽  
Hoa Thi Xuan Pham ◽  
Tho Quang Tran
Keyword(s):  
Reactive Power ◽  
Voltage Drop ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Output Impedance ◽  
Load Voltage ◽  
Analysis And Design ◽  
Proposed Model ◽  
Three Phase ◽  
Control Scheme

This paper presents a new load sharing technique for parallel-connected three-phase inverters in Standelone Microgrid. The paper proposed improvements droop controller to accurate load share by ratio with rated power of the inverter. In addition, the proposed scheme ensures reduced load voltage droop due to the load and droop. In the paper, the active power and reactive power are divided by voltage regulation under reference voltage in conditions of stark difference between line impedances, In addition the paper presents the ability to overcome the disadvantages of traditional droop scheme. The proposed model is simulated by Matlab-Simulink for 3 parallel-connected threephase inverters. The simulation results proved the technical soundness and advantages of the proposed in comparision with a tradition scheme even if the output impedance is resistance reactance in power sharing and load voltage drop reduce problems.

scholarly journals Distributed Finite-Time Secondary Frequency and Voltage Restoration Control Scheme of an Islanded AC Microgrid

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6266
Author(s):  
Junjie Ma ◽  
Xudong Wang ◽  
Siyan Zhang ◽  
Hanying Gao
Keyword(s):  
Power Distribution ◽  
Finite Time ◽  
Voltage Drop ◽  
Impedance Control ◽  
Reference Value ◽  
Voltage Regulation ◽  
Active Power ◽  
Power Sharing ◽  
Control Scheme ◽  
Voltage Deviation

To solve the problems of frequency and voltage deviation caused by the droop control while meeting the requirements of rapid response, a distributed finite-time secondary control scheme is presented. Unlike the traditional cooperative controllers, this scheme is fully distributed; each unit only needs to communicate with its immediate neighbors. A control protocol for frequency restoration and active power sharing is proposed to synchronize the frequency of each unit to the reference value, and achieve accurate active power distribution in a finite-time manner as well. The mismatch of the line impedance is considered, and a consensus-based adaptive virtual impedance control is proposed. The associated voltage drop is considered to be the compensator for the voltage regulation. Then, a distributed finite-time protocol for voltage restoration is designed. The finite-time convergence property and the upper bound of convergence times are guaranteed with rigorous Lyapunov proofs. Case studies in MATLAB are carried out, and the results demonstrate the effectiveness, the robustness to load changes, plug-and play capacity, and better convergence performance of the proposed control scheme.

scholarly journals The new power sharing method for threephase parallel inverters with nonlinear loads

2015 ◽  
Vol 18 (1) ◽  
pp. 16-28
Author(s):  
Phuong Minh Le ◽  
Dai Tan Le ◽  
Hoa Thi Xuan Pham
Keyword(s):  
Reactive Power ◽  
Energy System ◽  
Active Power ◽  
Power Sharing ◽  
Control Loop ◽  
Output Impedance ◽  
Nonlinear Loads ◽  
Control Scheme ◽  
Virtual Impedance

This paper presents a new method for controling parallel inverters to share active power and reactive power in the energy system with non-linear loads. In these systems, the virtual output impedance is usually added to the control loop of each inverter to improve the active power and reactive power sharing as well as the quality of the voltage system. Paper also proposes a kind of virtual impedance as a second-order general-integrator (SOGI) scheme. The simulation results in Matlab Simulink show the ability of the proposed controller to good share power P-Q, when connected with unbalanced and nonlinear loads. By using the proposed algorithm allows to reduce the voltage THD to 1.9% and 1.2% for unbalanced and nonlinear loads according by comparision with traditional control 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.

A Consensus-Based Adaptive Virtual Output Impedance Control Scheme for Reactive Power Sharing in Radial Microgrids

2021 ◽  
Vol 57 (1) ◽  
pp. 784-794
Author(s):  
Yi Chyn Cassandra Wong ◽  
Chee Shen Lim ◽  
Andrew Cruden ◽  
Mihai Dragos Rotaru ◽  
Pravat Kumar Ray
Keyword(s):  
Reactive Power ◽  
Impedance Control ◽  
Power Sharing ◽  
Output Impedance ◽  
Control Scheme

scholarly journals An Enhanced Distributed Voltage Regulation Scheme for Radial Feeder in Islanded Microgrid

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6092 ◽  
Author(s):  
Muhammad Zahid Khan ◽  
Chaoxu Mu ◽  
Salman Habib ◽  
Waleed Alhosaini ◽  
Emad M. Ahmed
Keyword(s):  
Supervisory Control ◽  
Reactive Power ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Load Voltage ◽  
Regulation Scheme ◽  
Control Schemes ◽  
System Frequency ◽  
Control Layer

Even the simplest version of the distribution networks face challenges such as maintaining load voltage and system frequency stability and at the same time minimizing the circulating reactive power in grid-forming nodes. As the consumers at the far end of the radial distribution network face serious voltage fluctuations and deviations once the load varies. Therefore, this paper presents an enhanced distributed control strategy to restore the load voltage magnitude and to realize power-sharing proportionally in islanded microgrids. This proposed study considers the voltage regulation at the load node as opposed to the inverter terminal. At the same time, a supervisory control layer is put on to observe and correct the load voltage and system frequency deviations. This presented method is aimed at replacing paralleled inverter control methods hitherto used. Stability analysis using system-wide methodical small-signal models, the MATLAB/Simulink, and experimental results obtained with conventional and proposed control schemes verify the effectiveness of the proposed methodology.

Adaptive SRF-PLL Based Voltage and Frequency Control of Hybrid Standalone WECS with PMSG-BESS

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Anjana Jain ◽  
R. Saravanakumar ◽  
S. Shankar ◽  
V. Vanitha
Keyword(s):  
Reactive Power ◽  
Frequency Control ◽  
Storage System ◽  
Synchronous Generator ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Control Scheme

Abstract The variable-speed Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) attracts the maximum power from wind, but voltage-regulation and frequency-control of the system in standalone operation is a challenging task A modern-control-based-tracking of power from wind for its best utilization is proposed in this paper for standalone PMSG based hybrid-WECS comprising Battery Energy Storage System (BESS). An Adaptive Synchronous Reference Frame Phase-Locked-Loop (SRF-PLL) based control scheme for load side bi-directional voltage source converter (VSC) is presented for the system. MATLAB/Simulink model is developed for simulation study for the proposed system and the effectiveness of the controller for bi-directional-converter is discussed under different operating conditions: like variable wind-velocity, sudden load variation, and load unbalancing. Converter control scheme enhances the power smoothening, supply-load power-matching. Also it is able to regulate the active & reactive power from PMSG-BESS hybrid system with control of fluctuations in voltage & frequency with respect to varying operating conditions. Proposed controller successfully offers reactive-power-compensation, harmonics-reduction, and power-balancing. The proposed scheme is based on proportional & integral (PI) controller. Also system is experimentally validated in the laboratory-environment and results are presented here.

scholarly journals Adaptive Gains Control Scheme for PMSG-Based Wind Power Plant to Provide Voltage Regulation Service

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 753 ◽  
Author(s):  
Jianfeng Dai ◽  
Yi Tang ◽  
Jun Yi
Keyword(s):  
Wind Speed ◽  
Power Plant ◽  
Wind Power ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Wind Power Plant ◽  
Control Scheme ◽  
Power Capability ◽  
Variable Wind ◽  
Voltage Support

High-penetration wind power will count towards a significant portion of future power grid. This significant role requires wind turbine generators (WTGs) to contribute to voltage and reactive power support. The maximum reactive power capacity (MRPC) of a WTG depends on its current input wind speed, so that the reactive power regulating ability of the WTG itself and adjacent WTGs are not necessarily identical due to the variable wind speed and the wake effect. This paper proposes an adaptive gains control scheme (AGCS) for a permanent magnet synchronous generator (PMSG)-based wind power plant (WPP) to provide a voltage regulation service that can enhance the voltage-support capability under load disturbance and various wind conditions. The droop gains of the voltage controller for PMSGs are spatially and temporally dependent variables and adjusted adaptively depending on the MRPC which are a function of the current variable wind speed. Thus, WTGs with lower input wind speed can provide greater reactive power capability. The proposed AGCS is demonstrated by using a PSCAD/EMTDC simulator. It can be concluded that, compared with the conventional fixed-gains control scheme (FGCS), the proposed method can effectively improve the voltage-support capacity while ensuring stable operation of all PMSGs in WPP, especially under high wind speed conditions.

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