scholarly journals Multiloop low bandwidth communication-based power sharing control for microgrids

2020 ◽  
Vol 21 (2) ◽  
pp. 682
Author(s):  
Erum Pathan ◽  
Afarulrazi Abu Bakar ◽  
Mubashir Hayat Khan ◽  
Muhammad Asad ◽  
Haider Arshad
Keyword(s):  
Reactive Power ◽  
Power Sharing ◽  
Control Technique ◽  
Voltage Source ◽  
Computational Burden ◽  
Voltage Source Inverters ◽  
Control Techniques ◽  
Equivalent Impedance ◽  
Control Scheme ◽  
Virtual Impedance

<span>In parallel-connected inverter-based microgrids, the reactive power sharing accuracy can not have satisfactory results effortlessly. Mismatch in feeder impedances of the parallel-connected inverter-based microgrids is a significant cause of inaccurate reactive power-sharing. In voltage source inverters (VSI) based microgrids, especially for the islanded mode of operation, the conventional centralized or decentralized control techniques are not much helpful to control the voltage deviations due to impedance mismatch. Mismatch of the feeder impedance is compensated by the addition of fixed virtual impedance. Whereas, the change in the virtual impedance is compensated by adaptive virtual impedance-based control techniques which are helpful to mitigate power-sharing errors, but in most of the control schemes virtual impedance-based control mechanism needs pre-knowledge of feeder impedance which increases the computational burden. This paper presents a decentralized virtual impedance-based power sharing control. In the proposed control solution to mitigate reactive power sharing errors in distributed generation (DG) units, mismatch of the parallel-connected feeder impedance is equalized by regulating the addition of equivalent impedance to each DG inverter. Proposed control technique offers an independent implementation without any pre-knowledge of the feeder impedance. Hence, the implementation of the control scheme is a straightforward and computational burden is also reduced. Simulation results show the effectiveness of the control scheme. </span>

Improved Load Sharing Control Techniques for Inverters used in a Microgrid

2009 ◽  
Vol 10 (1) ◽  
Author(s):  
Wei Yao ◽  
Zhaoming Qian
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Single Phase ◽  
Load Sharing ◽  
Power Sharing ◽  
Experimental Results ◽  
Control Technique ◽  
Transient Performance ◽  
Control Techniques ◽  
Control Scheme

In this paper, an improved load sharing control scheme is presented, which is able to improve the transient response and power sharing accuracy of parallel-connected inverters used in microgrid. It also shows how the improved droop method can be easily adapted to account for the operation of parallel-connected inverters, providing good performance under the variation and disturbance of loads, as well as achieving good steady-state objectives and transient performance. Two DSP-based single-phase Microgrid inverters are designed and implemented. Simulation and experimental results are all reported, confirming the validity of the proposed control technique.

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 Autonomous microgrid based parallel inverters using droop controller for improved power sharing

2020 ◽  
Vol 9 (6) ◽  
pp. 2302-2310
Author(s):  
Siddaraj Siddaraj ◽  
Udaykumar R. Yaragatti ◽  
Nagendrappa H. ◽  
Vikash Kumar Jhunjhunwala
Keyword(s):  
Energy Source ◽  
Reactive Power ◽  
Active Power ◽  
Power Sharing ◽  
Voltage Source ◽  
Voltage Source Inverters ◽  
Distributed Generators ◽  
Current Controller ◽  
Power Frequency

The existing microgrid has become a challenge to the sustainable energy source to provide a better quality of power to the consumer. To build a reliable and efficient microgrid, designing a droop controller for the microgrid is of utmost importance. In this paper, multiple voltage source inverters connected in parallel using an active power-frequency/reactive power-voltage droop scheme. The proposed method connected to two distributed generators local controllers, where each unit consists of a droop controller with an inner voltage-current controller and a virtual droop controller. By adding this controller to the microgrid reliability and load adaptability of an islanded system can be improved. This concept applied without any real-time communication to the microgrid. Thus, simulated using MATLAB/Simulink, the obtained results prove the effectiveness of the autonomous operation's microgrid model.

Effective Communication-Based Reactive Power Sharing Scheme for Meshed Microgrid in an Islanded Mode

2021 ◽  
Author(s):  
Anitha Daniel ◽  
Suchitra Dayalan
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Local Area ◽  
Power Sharing ◽  
Matlab Simulation ◽  
Distributed Generators ◽  
Control Scheme ◽  
Islanded Mode ◽  
Radial Network ◽  
Virtual Impedance

Microgrids (MGs) are the most sought out and feasible solution for the present energy crisis. MG is a group of Distributed Generators (DGs) interacting with each other to provide energy to a defined local area. The inclusion of DGs into the conventional power system at various voltage levels has altered the topology of the power system and their control techniques. Hence, the MGs can no longer be considered as a traditional radial network but rather a meshed network. The control and operation of such practical MGs become a challenge, especially when operated in the islanded mode. This research paper considers a realistic meshed MG operating in an islanded mode for study. In an islanded MG, the issues of real and reactive power sharing among DGs are addressed so that the power contribution of each DG is proportional to its rating, thus preventing overload and ensuring reliable operation. A communication-based virtual impedance estimation is proposed in addition to the droop controller for proportionate real and reactive power sharing among DGs in a meshed MG. With the increased complexity of meshed MG, the proposed communication-based control scheme offers an efficient reactive power sharing between DGs without the feeder and network impedance requirements. A MATLAB simulation study proves the effectiveness of the proposed control strategy for a meshed MG with equal DG ratings and unequal DG ratings under changing load conditions.

scholarly journals Detailed analysis of grid connected and islanded operation modes based on P/U and Q/f droop characteristics

2021 ◽  
Vol 12 (2) ◽  
pp. 772
Author(s):  
Qusay Salem ◽  
Khaled Alzaaree
Keyword(s):  
Reactive Power ◽  
Power Sharing ◽  
Control Technique ◽  
Voltage Source ◽  
Modes Of Operation ◽  
Control Structures ◽  
Operation Modes ◽  
Intentional Islanding ◽  
Synchronous Reference Frame ◽  
Islanded Operation

This paper presents a thorough control structure of the distributed generators inside the microgrid during both grid-connected and islanded operation modes. These control structures of the DGs voltage source inverters are implemented in synchronous reference frame (SRF) and controlled using linear PI controllers. By implementing the control structures, the desired real and reactive power can be efficiently transferred to the local loads and the utility load by the microgrid generating units. A modified droop control technique is introduced to facilitate the microgrid performance during both modes of operation. The active and reactive power sharing of the load demand between the utility grid and the microgrid can be performed by this drop control technique during the islanded mode. The system performance during intentional islanding event and utility load increase is investigated. The effectiveness of the offered control structures is confirmed through simulation results during both modes of operation.

Six-phase motor drive supplied by four voltage source inverters with synchronized space-vector PWM

2011 ◽  
Vol 60 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Valentin Oleschuk ◽  
Gabriele Grandi
Keyword(s):  
Continuous Phase ◽  
Power Sharing ◽  
Voltage Source ◽  
Motor Drive ◽  
Phase System ◽  
Space Vector Pwm ◽  
Space Vector ◽  
Voltage Source Inverters ◽  
Pulsewidth Modulation ◽  
Novel Method

Six-phase motor drive supplied by four voltage source inverters with synchronized space-vector PWMNovel method of space-vector-based pulsewidth modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive based on asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC-sources. Simulations show a behavior of six-phase system with continuous and discontinuous versions of synchronized PWM.

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