scholarly journals Harmonic reduction in a renewable energy islanded microgrid with fuzzy PID controller

2018 ◽  
Vol 7 (2.12) ◽  
pp. 380
Author(s):  
N S.Srivatchan ◽  
Dr P.Rangarajan
Keyword(s):  
Reactive Power ◽  
Harmonic Distortion ◽  
Power Sharing ◽  
Multilevel Inverter ◽  
Communication Link ◽  
Loop Control ◽  
Load Variations ◽  
Fuzzy Pid Controller ◽  
Variable Nature ◽  
Islanded Microgrid

Power sharing in an Islanded microgrid is not straight forward due to load variations as well as variable nature of Renewable En-ergy sources. This unequal power sharing leads to circulating currents, load imbalance and increased harmonic content. Traditional droop controller provides simple control for real power sharing without communication link, but they suffer from inaccurate reactive power sharing. To overcome the inherent drawback of traditional droop controller, this paper proposes cascaded H-bridge (CHB) multilevel inverter. CHB multilevel inverter provide increased output voltage, there by improves power quality. The Fuzzy Logic Con-troller provides simple and accurate control to CHB multilevel inverter. The proposed system is simulated in MATLAB Simulink Envi-ronment. This scheme provides closed loop control of DG units, in turn improves reactive power sharing between DG units, and thereby effectively reduces total harmonic distortion during islanding. The main focus of the paper is in power sharing issue on har-monic currents. The simulation results are verified with experimental microgrid hardware.  

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 An Improved Droop Control Strategy for Reactive Power Sharing in Islanded Microgrid

2015 ◽  
Vol 30 (6) ◽  
pp. 3133-3141 ◽  
Author(s):  
Hua Han ◽  
Yao Liu ◽  
Yao Sun ◽  
Mei Su ◽  
Josep M. Guerrero
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Power Sharing ◽  
Droop Control ◽  
Islanded Microgrid

scholarly journals A novel distributed event-triggered control for reactive power sharing based on hierarchical structure in islanded microgrid

2020 ◽  
pp. 002029402092475
Author(s):  
Yingwen Long ◽  
Yanxiang Zhu ◽  
Wei Zhang
Keyword(s):  
Hierarchical Structure ◽  
Reactive Power ◽  
Hierarchical Control ◽  
Power Sharing ◽  
Control Algorithms ◽  
Centralized Control ◽  
Nonlinear Loads ◽  
Distributed Generator ◽  
Islanded Microgrid ◽  
Event Triggered

Due to line impedance mismatches, nonlinear loads and other reasons, the traditional droop control algorithms have great limitations on the control of reactive power sharing. Distributed control algorithms based on hierarchical structure have become an effective approach for reactive power sharing compared with traditional centralized control methods. In this paper, an event-triggered control algorithm based on stability analysis of Lyapunov method is put forward in order to satisfy the demand of low-bandwidth communication for distributed generator in islanded microgrid. Subsequently, a distributed hierarchical control scheme adopting proposed event-triggered strategy is designed to achieve proportional reactive power sharing in an islanded microgrid. Finally, the feasibility and validity of the proposed algorithm are further verified in MATLAB/Simulink environment.

scholarly journals Analysis of Cross-Connected Half-Bridges Multilevel Inverter for STATCOM Application

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1898
Author(s):  
Yuan Li ◽  
Muhammad Humayun
Keyword(s):  
Pulse Width Modulation ◽  
Reactive Power ◽  
Control Method ◽  
Multilevel Inverter ◽  
Control Technique ◽  
Static Synchronous Compensator ◽  
Passive Element ◽  
Loop Control ◽  
In Series ◽  
Proportional Integral Controller

This paper suggested a single-phase cross-connected half-bridges multilevel inverter (cchb-mli) topology for static synchronous compensator (statcom) applications. The proposed mli structure consists of cross-connected multilevel cells connected in series with a more optimized number of devices to synthesize a higher number of voltage steps. Each cell in the structure consists of a set of switches and a dc-capacitor. Typically, when several dc-capacitors are used in an inverter, the dc voltages fluctuation occurs due to tolerance between passive element and asymmetric switch losses. A dual-loop control technique has been proposed with level-shifted pulse width modulation pwm to overcome these issues. The proposed methodology balances the dc-voltages using a proportional-integral controller by adjusting the switch duty cycle. The control method helps offset the issue of aggravated fluctuation while preserving the delivered reactive power distributed equally among the dc-capacitors at the same time. A thorough comparison is made between the proposed inverter concerning the number of components and efficiency to demonstrate the effectiveness of previous topologies. Moreover, a simulation model built in simulink and experimental results take from laboratory prototype to confirm the effectiveness of proposed structure and its control technique.

Predictive Direct Power Control (PDPC) of Grid-connected Dual-active Bridge Multilevel Inverter (DABMI)

2017 ◽  
Vol 8 (4) ◽  
pp. 1524 ◽  
Author(s):  
H.H. Goh ◽  
Azuwien Aida ◽  
S.S. Lee ◽  
S.Y. Sim ◽  
K.C. Goh
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Power Grid ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Energy Integration ◽  
Direct Power ◽  
Direct Power Control ◽  
Dual Active Bridge ◽  
Model Predictive Control Algorithm

This paper deals with controlling a grid-connected dual-active bridge multilevel inverter for renewable energy integration. The concept of direct power control is integrated with model predictive control algorithm, which is termed as predictive direct power control, to control the real and reactive power injected into the power grid. The proposed multilevel inverter allows more options of feasible voltage vectors for switching vector selections in order to generate multilevel outputs, and thereby obtaining high power quality in the power grid. By using the predictive direct power control, simulation results show that the proposed multilevel inverter produces lower power ripple and manage to achieve currents with low total harmonic distortion which are well within the IEEE standard. The modeling and simulation of the system are implemented and validated by MATLAB Simulink software.

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