The controller of voltage source inverter (VSI) is the essential part of distributed generation (DG) system as an interface in solving the power quality problems. In this paper, a new controller (based on feedback linearization) has been... more
The controller of voltage source inverter (VSI) is the essential part of distributed generation (DG) system as an interface in solving the power quality problems. In this paper, a new controller (based on feedback linearization) has been proposed due to achieving some prescribed behavior to mitigate the power quality problems. The new controller has been designed base on the average state space model of VSI and network which is nonlinear. The real time simulation of the proposed system shows precise tracing the load requirements and good mitigating the power quality problems rather than previous studies.
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This paper presents a new method for islanding detection in Microgrids with multiple distributed generations. The proposed method is based on feature extraction from power system current that is measured after distribution system circuit... more
This paper presents a new method for islanding detection in Microgrids with multiple distributed generations. The proposed method is based on feature extraction from power system current that is measured after distribution system circuit breaker. Comparing with traditional methods, because of changing in measuring point of current signal and using its transient data, this new method detects the islanding conditions faster. The method is simulated by PSCAD/EMTDC software and the utility current signal is processed by discrete wavelet transform by MATLAB TOOLBOX. The results have been compared with another method to show the speed and accuracy of the proposed method in islanding detection. Ability of this method for islanding detection in the network with multiple DGs is indicated by the results.
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ABSTRACT The integration of a capacitor-commutated converter (CCC) high-voltage direct current (HVDC) (CCC-HVDC) and voltage source converter (VSC) HVDC (VSC-HVDC) is proposed in this paper to supply entirely passive AC networks. The key... more
ABSTRACT The integration of a capacitor-commutated converter (CCC) high-voltage direct current (HVDC) (CCC-HVDC) and voltage source converter (VSC) HVDC (VSC-HVDC) is proposed in this paper to supply entirely passive AC networks. The key point of this integration is the flat characteristic of the DC voltage of the CCC-HVDC, which provides the condition for the VSC to connect to the CCC DC link via a current regulator. The advantages of the proposed combined infeeding system are the requirement of only one DC line, and better dynamic responses. The structure of the proposed infeeding system, as well as its control system, is studied. Simulation results are provided to validate the effectiveness of the proposed system and its control strategy. Two other schemes for infeeding AC passive networks are studied to demonstrate the advantages of the proposed system.
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ABSTRACT A general and effective framework for the secondary control of islanded microgrids (MGs) including inverter-based distributed generators and conventional generator is proposed in this study. The proposed framework works based on... more
ABSTRACT A general and effective framework for the secondary control of islanded microgrids (MGs) including inverter-based distributed generators and conventional generator is proposed in this study. The proposed framework works based on fuzzy potential function method and provides a clear vision for system designer in order to set the cooperation of different distributed energy resources (DERs) in regulating MG variables. Different potential functions are defined for each controllable microsource such that the minimum value of the potential function represents the microsource control target. The set points of DER units are dynamically updated by the optimisation unit located in MG central controller using available communication links. In addition, the small signal stability assessment is used to determine the parameter of the fuzzy potential function to guarantee the system stability. The simulation studies are carried out in the time-domain, using the developed program in MATLAB environment. The results demonstrate the effectiveness and flexibility of the proposed framework in the frequency and voltage control of islanded MGs.
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A new model of Interphase Power Controller (IPC) for controlling active power is introduced in this paper. In this model, which is called VSC-based IPC, the voltage source converter (VSC) does the function of the phase shifting... more
A new model of Interphase Power Controller (IPC) for controlling active power is introduced in this paper. In this model, which is called VSC-based IPC, the voltage source converter (VSC) does the function of the phase shifting transformer (PST) in IPC. This new structure not only has the features of IPC, but also controls the output power effectively when the input power is changed by alternation of the voltage or the phase angle of two networks.