scholarly journals Optimal P-Q Control of Grid-Connected Inverters in a Microgrid Based on Adaptive Population Extremal Optimization

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2107 ◽  
Author(s):  
Min-Rong Chen ◽  
Huan Wang ◽  
Guo-Qiang Zeng ◽  
Yu-Xing Dai ◽  
Da-Qiang Bi
Keyword(s):  
Constrained Optimization ◽  
Optimization Problem ◽  
Reactive Power ◽  
Active Power ◽  
Adaptive Genetic Algorithm ◽  
Constrained Optimization Problem ◽  
Extremal Optimization ◽  
Active And Reactive Power ◽  
Three Phase ◽  
Grid Connected Inverter

The optimal P-Q control issue of the active and reactive power for a microgrid in the grid-connected mode has attracted increasing interests recently. In this paper, an optimal active and reactive power control is developed for a three-phase grid-connected inverter in a microgrid by using an adaptive population-based extremal optimization algorithm (APEO). Firstly, the optimal P-Q control issue of grid-connected inverters in a microgrid is formulated as a constrained optimization problem, where six parameters of three decoupled PI controllers are real-coded as the decision variables, and the integral time absolute error (ITAE) between the output and referenced active power and the ITAE between the output and referenced reactive power are weighted as the objective function. Then, an effective and efficient APEO algorithm with an adaptive mutation operation is proposed for solving this constrained optimization problem. The simulation and experiments for a 3kW three-phase grid-connected inverter under both nominal and variable reference active power values have shown that the proposed APEO-based P-Q control method outperforms the traditional Z-N empirical method, the adaptive genetic algorithm-based, and particle swarm optimization-based P-Q control methods.

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.

Modified Power Compensation Control Strategy of Three-Phase Grid-Connected Inverter under Unbalanced Grid Voltage Conditions

2015 ◽  
Vol 740 ◽  
pp. 335-338 ◽  
Author(s):  
Shao Hua Sun ◽  
Hong Qi Ben
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Positive Sequence ◽  
Grid Voltage ◽  
Compensation Control ◽  
Active And Reactive Power ◽  
Three Phase ◽  
Grid Connected Inverter ◽  
Three Phase Inverter ◽  
Unbalanced Grid

Control strategy under unbalanced grid voltage conditions is one of the most important issues for grid-connected inverter. Under unbalanced grid voltage conditions, the 2nd active and reactive power ripples generate, they pollute the grid. To meet the demands of IEEE Std.929-2000, this paper proposed a modified power compensation control strategy; the proposed solution is based on direct power control. To provide accurate compensating power, the power model of three-phase inverter under unbalanced grid voltage conditions is given, using the positive sequence current component and the negative sequence voltage component, the compensating powers are calculated in details. Theoretical analysis and comparative simulation verification are presented to demonstrate the effectiveness of the proposed control strategy.

scholarly journals Design of Hybrid Grid-Connected Inverter for Renewable Energy Generation with Power Quality Conditioning

2019 ◽  
Vol 8 (3) ◽  
pp. 2256-2262
Keyword(s):  
Reactive Power ◽  
Active Power ◽  
Parameter Design ◽  
Harmonic Compensation ◽  
Proposed Model ◽  
Three Phase ◽  
Hybrid Grid ◽  
And Performance ◽  
Grid Connected Inverter ◽  
Renewable Energy Generation

This research paper presents a new model of hybrid grid connected inverter (HGCI) which replaces the use of capacitive-coupled grid connected inverter (CGCI) and inductivecoupled grid connected inverter (IGCI). As CGCI have narrow operation range and IGCI needs more PV panels thus HGCI overcomes the limitations of both inverters by providing wide operation range and less PV panels are required. The proposed model has a three-phase full-bridge DC/AC electrical converter with a thyristors-controlled LC (TCLC) filter to transfer active power and performs reactive power compensation and also harmonic compensation. At the end results, parameter design and performance of HGCI have been verified by MATLAB/Simulink.

Decoupling Control Strategy for Conergy Three-Level Three Phase Grid Converter

2014 ◽  
Vol 986-987 ◽  
pp. 1205-1209 ◽  
Author(s):  
Shi Min Shan ◽  
Wei Chi Ou ◽  
Ya Feng
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
High Efficiency ◽  
Reactive Power ◽  
Decoupling Control ◽  
Active And Reactive Power ◽  
Three Phase ◽  
Integral Controller ◽  
Proportional Integral Controller ◽  
Grid Connected Inverter

Conergy three-level NPC topology is often used in grid connected inverter due to its high efficiency, fewer switching devices and better EMI performance. Traditional half-bridge topology can be transformed to Conergy NPC topology by adding bi-direction switches. This paper proposed a novel control strategy for Conergy three-level NPC three phase grid converter with real and reactive power closed-loop controller in the synchronous d-q rotating frame. The power control loop is based on the feed forward decoupling of d-axis and q-axis components of the output current, thus the active and reactive power can be controlled separately. Additionally a proportional-integral controller is added to enhance the robustness of the power controller. Simulation results verify the effectiveness of the proposed strategy.

scholarly journals Nonconvex constrained optimization by a filtering branch and bound

2020 ◽  
Author(s):  
Gabriele Eichfelder ◽  
Kathrin Klamroth ◽  
Julia Niebling
Keyword(s):  
Constrained Optimization ◽  
Optimization Problem ◽  
Feasible Solution ◽  
Constrained Optimization Problem ◽  
Numerical Tests ◽  
Nonconvex Constrained Optimization ◽  
Objective Value ◽  
Feasible Solutions ◽  
Quality Guarantee ◽  
Single Objective

AbstractA major difficulty in optimization with nonconvex constraints is to find feasible solutions. As simple examples show, the $$\alpha $$ α BB-algorithm for single-objective optimization may fail to compute feasible solutions even though this algorithm is a popular method in global optimization. In this work, we introduce a filtering approach motivated by a multiobjective reformulation of the constrained optimization problem. Moreover, the multiobjective reformulation enables to identify the trade-off between constraint satisfaction and objective value which is also reflected in the quality guarantee. Numerical tests validate that we indeed can find feasible and often optimal solutions where the classical single-objective $$\alpha $$ α BB method fails, i.e., it terminates without ever finding a feasible solution.

Reactive Power Compensation for Unbalanced Fluctuating Loads by Using Two-Dimensional Space Vector and a Static Var Compensator

2014 ◽  
Vol 533 ◽  
pp. 397-400 ◽  
Author(s):  
Chi Jui Wu ◽  
Yu Wei Liu ◽  
Shou Chien Huang
Keyword(s):  
Power Factor ◽  
Reactive Power ◽  
Dimensional Space ◽  
Measurement Data ◽  
Power Source ◽  
Active Power ◽  
Two Dimensional ◽  
Static Var Compensator ◽  
Space Vector ◽  
Three Phase

To modify the power factor and balance the three-phase currents simultaneously, this paper proposes the instantaneous compensator to calculate the compensation current. The instantaneous compensator utilizes two-dimensional instantaneous space vector and setting the active power as a constant for each cycle which can improve power quality effectively. Moreover, the instantaneous compensator requires an independent power source, whose capacity can be reduce by using a static var compensator (SVC). An SVC does not interfere with the capability of the instantaneous compensator. Field measurement data were analyzed. Simulation results confirmed the feasibility of correcting the power factor and balancing load currents simultaneously using the proposed method.

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