scholarly journals Droop Control in DQ Coordinates for Fixed Frequency Inverter-Based AC Microgrids

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1168 ◽  
Author(s):  
Mohamed Toub ◽  
Mehrzad M. Bijaieh ◽  
Wayne W. Weaver ◽  
Rush D. Robinett III ◽  
Mohamed Maaroufi ◽  
...  
Keyword(s):  
Reactive Power ◽  
Control Technique ◽  
Droop Control ◽  
Control Methods ◽  
Fixed Frequency ◽  
Active And Reactive Power ◽  
Bus Voltage ◽  
High Level ◽  
System Frequency ◽  
Frequency Inverter

This paper presents a proof-of-concept for a novel dq droop control technique that applies DC droop control methods to fixed frequency inverter-based AC microgrids using the dq0 transformation. Microgrids are usually composed of distributed generation units (DGUs) that are electronically coupled to each other through power converters. An inherent property of inverter-based microgrids is that, unlike microgrids with spinning machines, the frequency of the parallel-connected DGUs is a global variable independent from the output power since the inverters can control the output waveform frequency with a high level of precision. Therefore, conventional droop control methods that distort the system frequency are not suitable for microgrids operating at a fixed frequency. It is shown that the proposed distributed droop control allows accurate sharing of the active and reactive power without altering the microgrid frequency. The simulation and hardware-in-the-loop (HIL) results are presented to demonstrate the efficacy of the proposed droop control. Indeed, following a load change, the dq droop controller was able to share both active and reactive power between the DGUs, whereas maintaining the microgrid frequency deviation at 0% and the bus voltage deviations below 6% of their respective nominal values.

scholarly journals Active and reactive power sharing in micro grid using droop control

2020 ◽  
Vol 10 (3) ◽  
pp. 2235
Author(s):  
Omar Feddaoui ◽  
Riad Toufouti ◽  
Labed Djamel ◽  
Salima Meziane
Keyword(s):  
Renewable Energy ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Power Sharing ◽  
Electrical Network ◽  
Droop Control ◽  
Intelligent Network ◽  
Active And Reactive Power ◽  
Software Information ◽  
High Level

The development of renewable energy contributes to the global objectives of reducing our greenhouse gas emissions, obtaining and increasing our energy efficiency. In the face of these changes, the electric-network must adapt, while maintaining a high level of reliability and a quality of energy production. To meet this objective, it is recommended to use highly developed electrical network by integrating renewable energy sources in order to adapt the energy consumption to their production, using electro-technical software information and telecommunications technologies. We are talking about intelligent grids (Smart Grid). The main objective of the work presented in this paper is the contribution to the study of intelligent network for efficient management of energy produced by several sources linked to the AC bus via the voltage inverters. Numerical simulations have been presented to validate the performance of the proposed active and reactive power controller (Droop Control).

scholarly journals Capacity Limitation Control of Multiple Bi-directional DC-DC Converters for Micro Grid Application

2015 ◽  
Vol 2 (1) ◽  
pp. 61 ◽  
Author(s):  
S. J. Chiang ◽  
Yu-Min Liao ◽  
Ke-Chih Liu
Keyword(s):  
Power Management ◽  
Control Method ◽  
Droop Control ◽  
Control Methods ◽  
Power Capacity ◽  
Capacity Limitation ◽  
Current Sharing ◽  
Parallel Control ◽  
Micro Grid ◽  
Bus Voltage

The micro grid system requires battery for energy storage and power management. In which, the bi-directional DC to DC converter is the key component for maintaining the DC bus voltage and controlling the charge and discharge of the battery with or without grid support. Parallel control of multiple DC to DC converters is a critical technique to enlarge the power capacity. This paper presents two capacity limitation control methods that multiple DC to DC converters can be paralleled with distributed battery banks. The first method is the capacity limitation control with cascaded load current sense needing no control interconnection. The second method is the capacity limitation control with master-slave and cascaded current command limitation. Two methods are presented to solve the limitation of droop control method and active current sharing method respectively, and can be extended without converter number limitation theoretically. Three prototype 240W bidirectional half-bridge DC to DC converters are built and paralleled in this paper. The proposed method is confirmed with some measured results.

A New Improved Walsh Function Algorithm for Active and Reactive Power Measurement

2014 ◽  
Vol 67 (3) ◽  
Author(s):  
Garba Aliyu ◽  
Saifulnizam Abd. Khalid ◽  
Jafaru Usman ◽  
Ahmad Fuad A. Aziz ◽  
Hussein Shareef
Keyword(s):  
Reactive Power ◽  
Walsh Function ◽  
Power Measurement ◽  
Nonlinear Load ◽  
Active And Reactive Power ◽  
Linear Load ◽  
Alternative Approach ◽  
Three Phase ◽  
Linear And Nonlinear ◽  
High Level

This paper present improved Walsh function (IWF) algorithm as an alternative approach for active and reactive power measurement in linear and nonlinear, balanced and unbalanced sinusoidal three phase load system. It takes advantage of Walsh function unified approach and its intrinsic high level accuracy as a result of coefficient characteristics and energy behaviour representation. The developed algorithm was modeled on the Matlab Simulink software; different types of load, linear and nonlinear were also modeled based on practical voltage and current waveforms and tested with the proposed improved Walsh algorithm. The IEEE standard 1459-2000 which is based on fast Fourier transform FFT approach was used as benchmark for the linear load system while a laboratory experiment using Fluke 435 power quality analyzer PQA which complies with IEC/EN61010-1-2001standards was used to validate the improved algorithm for nonlinear load measurement. The results showed that the algorithm has the potential to effectively measure three phase power components under different load conditions.

scholarly journals Power Management in Hybrid Microgrid

2020 ◽  
Vol 9 (5) ◽  
pp. 1964-1969
Keyword(s):  
Power Management ◽  
Management Strategy ◽  
Load Sharing ◽  
Control Technique ◽  
Droop Control ◽  
Hybrid Microgrid ◽  
Management Algorithm ◽  
Power Management Strategy ◽  
Maximum Power Tracking ◽  
Bus Voltage

This paper is representing power management in a hybrid microgrid. The hybrid microgrid consists of PV, wind, battery, and grid. The power management strategy is mentioned in islanding and grid-connected mode. In a grid-connected system, the grid converter has to monitor and manage the power to flow between microgrid and grid. The voltage shifting based droop control technique is used in DG for proper load sharing when two sources are connected in parallel. DG units in hybrid microgrid have two switching modes including droop control and maximum power tracking (MPPT). The operation of a hybrid microgrid is operated in different thee mode. The bus voltage is the main carrier to switching the mode of a hybrid microgrid. The power management algorithm for hybrid microgrid described here. This renewable-based hybrid microgrid model can be used for different aspects like small residential and commercial buildings. The feasibility and effectiveness of this strategy for hybrid microgrid running in various modes verified by simulation result.

scholarly journals Decentralize power sharing control strategy in islanded microgridsDecentralize power sharing control strategy in islanded microgrids

2020 ◽  
Vol 20 (2) ◽  
pp. 752
Author(s):  
Mubashir Hayat Khan ◽  
Shamsul Aizam Zulkifli ◽  
Erum Pathan ◽  
Elhassan Garba ◽  
Ronald Jackson ◽  
...  
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Pi Controller ◽  
Power Sharing ◽  
Control Technique ◽  
Droop Control ◽  
Low Load ◽  
Islanded Mode ◽  
The Stability ◽  
The Cost

<a name="_Hlk16093850"></a><span>Droop control technique is one of the renowned techniques which does not need any communication connection between Distibuted Generations (DG), hence the cost, as well as the reliability of the microgrid (MG) system can be reduced. MG is operated in two modes as their functionality and structure is concern. These are the grid connected or islanded (stand-alone) mode. DGs operating values may have different ratings of voltage, power and line impedance. The power sharing in these operatng conditions is not shared equally by all DGs connected in the system and also during load changes conditions power sharing accuracy is difficult to achieve. In this paper, a droop power control is used to balance the power sharing in islanded mode. As from the results, the active power sharing is equally shared from all DGs connected in the microgrid system. However, reactive power sharing accuracy always disturbed when there is impedance mismatch among the different DG feeders. The accuracy is done by monitoring the effects when load changes for low load to high load or vice versa. The Proportional Integral (PI) controller has been used to minimize the reactive power errors. At the end, the power droop is capable to share power accurately and results prove the stability and reliability of the proposed technique.</span>

scholarly journals Direct Power-Based Three-Phase Matrix Rectifier Control with Input Power Factor Adjustment

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1427 ◽  
Author(s):  
Jae-Chang Kim ◽  
Dongyeon Kim ◽  
Sang-Shin Kwak
Keyword(s):  
Power Factor ◽  
Reactive Power ◽  
Current Source ◽  
Input Power ◽  
Control Technique ◽  
Unity Power Factor ◽  
Light Load ◽  
Active And Reactive Power ◽  
The Given ◽  
Power Factor Control

In a current source rectifier such as a matrix rectifier, input voltage and current cannot be in phase unless an additional input power factor control technique is implemented. This paper proposes such a technique for a matrix rectifier using power-based space vector modulation (SVM). In the proposed method, the modulation index and phase required in order to apply the SVM are calculated based on the active and reactive power of the rectifier for intuitive power factor control. The active power that the rectifier should generate for the regulation of the output inductor current is obtained by the PI (proportional-integral) controller. The reactive power, which is supplied by the rectifier for adjustment of the power factor, is assigned differently depending on the output condition: for the output condition capable of unity power factor, it is set to a negative value of reactive power of the input capacitor, and when the unity power factor is not achievable, it is set with the maximum reactive power the rectifier can generate under the given condition to attain the maximum possible input power factor. It is determined whether the given condition is the light load condition by comparing the absolute value of the reactive power supplied by the input capacitor with the maximum rectifier reactive power that can be produced under the given condition. The SVM based on the active and reactive power of the rectifier in this technique allows the input power factor control to be intuitive and simple. The performance and feasibility of the technique were proved by simulation and experimentation.

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.

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