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Self tuning filter and fuzzy logic control of shunt active power filter for eliminates the current harmonics constraints under unbalanced source voltages and loads conditions

Chebabhi A., Abdelhalim K., Fellah F. M. K.

Journal of Power Technologies

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2018

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Vol. 98, nr 1

1--19

EN

Shunt active power filters (SAPFs) are modern filtering technologies for source current harmonic elimination and source reactive power compensation of nonlinear loads. In the case of normally balanced source voltages, the SAPFs are controlled to eliminate a wide range of source current harmonics and compensate the source reactive power generated by non-linear loads to provide source current functions with maximum power factor. However, if source voltages are unbalanced and/or distorted, these control objectives cannot be achieved, which impacts the SAPFs performances. In the present paper, we propose a new modification to extend the stable dynamic range and to enhance the transient response of a classical phase locked loop (CPLL). An enhanced phase locked loop (EPLL) based on a self tuning filter (STF) and fuzzy logic control (FLC) associated with SRF theory are used in four leg shunt active power filter control under unbalanced source voltages and nonlinear loads. The aim is to enable the SAPFs to reach a higher compensation level of reactive power and current harmonics for all cases of source voltages and nonlinear loads for the limits specified in IEEE Std. 519. The success, robustness, and effectiveness of proposed control circuits are demonstrated through simulation, using Sim Power Systems and S-Function of MATLAB/SIMULINK.

2

Designing of power system stabilizer based on the root locus method with lead-lag controller and comparing it with PI controller in multi-machine power system

Jalali S., Shahgholian G.

Journal of Power Technologies

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2018

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Vol. 98, nr 1

45--56

EN

This paper presents a method for designing a multi-machine power system stabilizer. The conventional design technique using a single machine infinite bus approximation involves a frequency response estimation called GEP(s). Frequency response is estimated between the input AVR and electrical output torque. The power system stabilizer is designed by frequency response and based on the root locus method to improve the damping of oscillatory modes. By using this method, we can adjust the structure of the PSS compensator and its parameters in the multi-machine system and it does not need to know the equivalent reactance of output and voltage of the infinite bus or the other estimations in every machine. In the proposed method, information available at the high voltage bus of the step-up transformer is used to set up a modified Heffron-Phillips model. Finally, this method is examined on three test systems. Simulation results indicate the performance and effectiveness of the proposed method.

3

Four Leg DSTATCOM based on Synchronous Reference Frame theory with Enhanced Phase Locked Loop for compensating a four wire distribution network under unbalanced PCC voltages and loads

Chebabhi A., Fellah M.-K., Kessal A., Benkhoris M.-F.

Journal of Power Technologies

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2016

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Vol. 96, nr 1

15--26

EN

This paper presents a Distribution Static Compensator based on Four Leg Voltage Source Inverter (4-leg VSI DSTATCOM) with controlling by Synchronous Reference Frame theory (SRF) in the dq0 frame with Enhanced Phase Locked Loop based on Self-Tuning Filter (EPLL-STF) used for compensating four-wire distribution systems.The proposed 4-leg VSI DSTATCOM is used for load balancing, source harmonics filtering, reactive power compensation and power factor correction, and source neutral wire current compensation at the point of common coupling (PCC) in the four-wire distribution network under unbalanced linear loads and nonlinear load variation with various source and PCC voltages conditions. The new SRF theory with EPLL based on STF is used for harmonics current extraction and good estimation of PCC voltages without harmonics under unbalanced PCC voltages and loads. Three dimensional space vector modulation (3D SVM) is used to generate the gate switching pulses for the 4-leg VSI and to circumvent the problems of the switching frequency variant, and for DC bus voltage capacitor and compensating 4-leg VSI DSTATCOM currents we are going to use the PI controller (Proportional-Integral). The effectiveness of the proposed 4-leg DSTATCOM under unbalanced PCC voltages and loads with various control strategies are demonstrated through simulation using sim-power-system and S-Function integrated in Matlab simulink.