An enhanced droop control scheme for resilient active power sharing in paralleled two-stage PV inverter systems

2016 ◽  
Author(s):  
Hongpeng Liu ◽  
Yongheng Yang ◽  
Xiongfei Wang ◽  
Poh Chiang Loh ◽  
Frede Blaabjerg ◽  
...  
Keyword(s):  
Active Power ◽  
Power Sharing ◽  
Droop Control ◽  
Two Stage ◽  
Pv Inverter ◽  
Control Scheme

scholarly journals An Enhanced Dual Droop Control Scheme for Resilient Active Power Sharing Among Paralleled Two-Stage Converters

2017 ◽  
Vol 32 (8) ◽  
pp. 6091-6104 ◽  
Author(s):  
Hongpeng Liu ◽  
Yongheng Yang ◽  
Xiongfei Wang ◽  
Poh Chiang Loh ◽  
Frede Blaabjerg ◽  
...  
Keyword(s):  
Active Power ◽  
Power Sharing ◽  
Droop Control ◽  
Two Stage ◽  
Control Scheme

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 Enhanced Control Scheme for a Three-Phase Grid-Connected PV Inverter under Unbalanced Fault Conditions

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1247
Author(s):  
Saeid Abbasi ◽  
Ali Asghar Ghadimi ◽  
Amir Hossein Abolmasoumi ◽  
Mohammad Reza Miveh ◽  
Francisco Jurado
Keyword(s):  
Reactive Power ◽  
Control Strategies ◽  
Active Power ◽  
Reactive Control ◽  
Pv System ◽  
Pv Inverter ◽  
Three Phase ◽  
Control Scheme ◽  
Double Grid ◽  
Unbalanced Grid

This paper presents an improved control strategy to cancel the double grid frequency oscillations in the active power, reactive power, and DC-link voltage of a three-phase grid-connected photovoltaic (PV) system under unbalanced grid condition. To achieve these goals, an enhanced positive–negative-sequence control (PNSC) to remove oscillations of active power and an instantaneous active–reactive control (IARC) to mitigate the fluctuations of active and reactive power, simultaneously, are suggested. These methods are also effective to reduce the oscillations of the DC-link voltage. To track the desired unbalanced or harmonic reference currents, improved proportional resonant (PR) current controllers have been designed using the Bode frequency analysis. Simulation studies are carried out via Matlab/Simulink® software to verify the effectiveness of the suggested control strategies.

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.

Multiple Inverters Operated in Parallel for Proportional Load Sharing in Microgrid

2017 ◽  
Vol 8 (2) ◽  
pp. 654 ◽  
Author(s):  
Chethan Raj D ◽  
D N Gaonkar
Keyword(s):  
Power Sharing ◽  
Basic Unit ◽  
Droop Control ◽  
Class A ◽  
Three Phase ◽  
Control Scheme ◽  
New Energy ◽  
Parallel Control ◽  
Lc Filter ◽  
Three Phase Inverter

<p class="a">The new energy source utilization and development, gradual rise of distributed power grid miniaturization, intelligence, control has become a trend. In order to make microgrid reliable and efficiently run, control technology of microgrid has become a top priority and an inverter as microgrid basic unit, its control has become the most  important part in microgrid. In this paper, three inverters are operated in parallel using an P-V/Q-F droop control is investigated. Mathematical model of three phase inverter with LC filter is derived, which is based on the voltage and current dual control loop. Parallel control strategy based on P-V/Q-F droop control, does not require a real time communications between the inverters and more suitable for microgrid applications. To verify the feasibility and validity of the droop control scheme, simulation is done in Matlab/Simulink and results indicate droop control has significant effect on power sharing and balancing the voltage magnitude, frequency.</p>

scholarly journals An accurate reactive power control study in virtual flux droop control

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 948-953
Author(s):  
Aimeng Wang ◽  
Jia Zhang
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Control Method ◽  
Power Sharing ◽  
Control Voltage ◽  
Droop Control ◽  
Reactive Power Control ◽  
Control Scheme ◽  
Static Performance ◽  
Virtual Flux

AbstractThis paper investigates the problem of reactive power sharing based on virtual flux droop method. Firstly, flux droop control method is derived, where complicated multiple feedback loops and parameter regulation are avoided. Then, the reasons for inaccurate reactive power sharing are theoretically analyzed. Further, a novel reactive power control scheme is proposed which consists of three parts: compensation control, voltage recovery control and flux droop control. Finally, the proposed reactive power control strategy is verified in a simplified microgrid model with two parallel DGs. The simulation results show that the proposed control scheme can achieve accurate reactive power sharing and zero deviation of voltage. Meanwhile, it has some advantages of simple control and excellent dynamic and static performance.

scholarly journals A New Adaptive Control Strategy of active and reactive power sharing in Islanded Microgrids

2016 ◽  
Vol 19 (4) ◽  
pp. 14-34
Author(s):  
Phuong Minh Le ◽  
Duy Vo Duc Hoang ◽  
Hoa Thi Xuan Pham ◽  
Huy Minh Nguyen ◽  
Dieu Ngoc Vo
Keyword(s):  
Transmission Line ◽  
Distributed Generation ◽  
Reactive Power ◽  
Active Power ◽  
Power Sharing ◽  
Droop Control ◽  
Active And Reactive Power ◽  
Three Phase ◽  
Islanded Microgrid ◽  
Adaptive Control Strategy

This paper proposes a new control sharing method for parallel three-phase inverters in an islanded microgrid. The proposed technique uses adaptive PIDs combined with the communication among the parallel inverters to accurately share active power and reactive power among the inverters via adjusting the desired voltage if there is a distinct difference between line impedance and the load change in the microgrid. Moreover, the paper also presents the response ability of the inverters to maintain the error within the allowed limits as the transmission line is interrupted. The proposed technique has been verified in a microgrid with three parallel distributed generation-inverter units using Matlab/Simulink. In the simulation, as the droop control using the communication information among the inverters, the sharing errors for active power and reactive power are around 0.2% and 0.6%, respectively. As the connection between the microgrid and transmission line is interrupted, the sharing errors for active power and reactive power increase to 0.4% and 2%, respectively. The simulation results have indicated that the proposed technique is superior to the traditional droop control in terms of the accuracy and stability. Therefore, the new proposed technique can be a favor alternative model for active power and reactive power sharing control of parallel inverters in an islanded microgrid.

scholarly journals Improved Droop Control with Washout Filter

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2415 ◽  
Author(s):  
Yalong Hu ◽  
Wei Wei
Keyword(s):  
Dynamic Performance ◽  
Singular System ◽  
Active Power ◽  
Power Sharing ◽  
Droop Control ◽  
Hardware In The Loop ◽  
Signal Model ◽  
Modeling Technology ◽  
Small Signal Model ◽  
Washout Filter

In this paper, a droop washout filter controller (DWC), composed of a conventional droop controller and a washout filter controller, is proposed. The droop controller is used to ensure the “plug-and-play” capability, and the droop gain is set small. The washout filter is introduced to compensate the active power dynamic performance (APDP). Compared to the droop controller, the DWC can achieve accurate active power sharing and smaller frequency difference without losing the APDP. Additionally, a novel modeling technology is proposed, using which a small-signal model for an island microgrid (MG) is constructed as a singular system. The system’s stability is analyzed and the DWC is verified using real-time (RT-LAB) simulation with hardware in the loop (HIL).

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