A novel control scheme for microgrid inverters seamless transferring between grid-connected and islanding mode

Ahmed, Ishaq; Sun, Longting; Chen, Xin

doi:10.1109/cieec.2017.8388423

Cited by 7 publications

(7 citation statements)

References 10 publications

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“…where is the dc link voltage, is the switching frequency of the inverter switches and r is the ratio between inverter side inductor and grid side inductor and the value of r is be considered based on the nominal grid impedance and the resonant frequency from the transfer function of the filter. The resonant frequency is specified by (10) and the constraint is given by (11)…”

Section: Design Of Lcl Filtermentioning

confidence: 99%

“…There are different control structures proposed in the literature for achieving fluctuations free transfer between the operating modes [9][10][11][12][13][14][15][16][17][18][19][20][21] to retain the power quality during the transfers. Conventionally, an inverter that is connected to the grid is controlled as PQ control to feed/take power to/from the utility, and when the inverter gets disconnected from the grid V/f control is used for the maintenance of voltage across the load.…”

Section: Introductionmentioning

confidence: 99%

“…When there is a need for switching between the modes, then switching between the controllers has to take place, which may lead to large transients and further may lead to system collapse. The inverter, when being operated as utility connected, is to be treated as a current source and when it gets disconnected from the utility, it is operated as a voltage source [9][10][11]. A droop characteristic adjustment based control scheme has been proposed in [12].…”

Section: Introductionmentioning

confidence: 99%

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Seamless Transition in Grid-connected Microgrid System using Proportional Resonant Controller

Lavanya

Kumar

2020

IJE

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In this paper, the design of an inverter control structure based on the Proportional Resonant (PR) controller is dealt with in detail for attaining smooth transitions between the operating modes of a gridconnected microgrid system. The control strategy applied for the inverter is cascaded three-loop control viz., the grid current, voltage across the load, and the inverter output current loops. The inverter control is mainly focused to retain the voltage magnitude within the prescribed set limits and to have a good quality of the voltage across the load under all the modes of operation. A proportional resonant controller is designed by considering the transients and stability criteria into account under varying modes of operation. The design procedure of the Proportional resonant controller is given in detail. The threephase grid-connected microgrid system considered under study is simulated in MATLAB/Simulink environment to operate under islanding condition as well as grid-connected condition and also changing modes from islanding to grid connected and vice versa. The simulation results are presented under various modes of operation to validate the controller design for a smooth transition between the modes of operation.

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Section: Design Of Lcl Filtermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seamless Transition in Grid-connected Microgrid System using Proportional Resonant Controller

Lavanya

Kumar

2020

IJE

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“…In [9], a master inverter is set to build up the AC voltage and other inverters can still work in the grid-tied mode to supply continuous power. Unified schemes based on indirect current control are devised to impose no alteration to the control structure so that the output voltage and injected current can transmit smoothly with no shock [10][11][12]. In [13,14], smooth transition mechanisms based on state observer are discussed to maintain the system variables within acceptable limits.…”

Section: Introductionmentioning

confidence: 99%

Compulsory Islanding Transition Strategy Based on Fuzzy Logic Control for a Renewable Microgrid System

Wan

Wang

2021

Mathematical Problems in Engineering

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Advantages of microgrid integrated with a renewable energy system have been acknowledged in more and more applications. Operating steadily during different modes is of great significance, and different modes transferring must be transient, seamless, and reliable to maintain the continuous electricity supply for loads, especially sensitive ones. As a semicontrolled switch that is unable to shut instantly until the zero point of its current, thyristors should be forced to be turned off by certain strategies to minimise the influence brought by the delay of modes transferring. In this paper, a compulsory turn-off strategy based on fuzzy logic control of converter output voltage is proposed. With the strategy, an alterable reverse voltage is applied across the conducting thyristor by dynamically adjusting the output voltage reference instruction and closed-loop control parameters depending on the changing rate rather than detecting the polarity of voltage or current. Constraints from acquisition of analog data and error of digital calculation will be eliminated. Finally, simulation and experimental results verify the effectiveness of the proposed strategy.

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“…A Master-slave control is another common approach in microgrid where a Master unit i.e., the Voltage Source Inverter (VSI) which is being controlled by PQ control structure for regulating the real and reactive power fed into the grid and under islanding mode, the master unit is to be controlled as Voltage/frequency (V-f) control for maintaining the voltage and frequency [26]. A novel control scheme has been developed in [27] which consist of capacitor voltage controller as outer loop and inductor current controller as inner loop for improving the voltage quality during the transition.…”

Section: Introductionmentioning

confidence: 99%

Control strategies for seamless transfer between the grid-connected and islanded modes of a microgrid system

Lavanya

Kumar

2020

IJECE

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Design of control strategies for Distributed generation systems is very important to achieve smoother transition between the grid connected and islanding modes of operation. The transition between these two modes of operation should be seamless, without any severe transients during the changeover. In this paper, two different control strategies namely inverter output current control and indirect grid current control for the seamless transfer between the modes of operation has been explored for the suitability. The design and analysis of the cascaded control loops based on Proportional Integral (PI) controller has been dealt in detail for both inverter output current control and indirect grid current control strategy. Control parameters are designed using the control system toolbox in MATLAB. A 10kW grid connected microgrid system has been designed and simulated in MATLAB/Simulink and the results are presented under grid connected operation, islanding operation and the transition between the modes considering fault condition in the grid side. The simulation studies are carried out using both the control strategies and the results are presented to validate the design methodology.

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A novel control scheme for microgrid inverters seamless transferring between grid-connected and islanding mode

Cited by 7 publications

References 10 publications

Seamless Transition in Grid-connected Microgrid System using Proportional Resonant Controller

Seamless Transition in Grid-connected Microgrid System using Proportional Resonant Controller

Compulsory Islanding Transition Strategy Based on Fuzzy Logic Control for a Renewable Microgrid System

Control strategies for seamless transfer between the grid-connected and islanded modes of a microgrid system

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