scholarly journals Control and Design Constraints of Compensators for Mitigation of Harmonics in Photovoltaic Inverter

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3386-3390
Keyword(s):  
Transient Response ◽  
Lower Order ◽  
Frequency Deviation ◽  
International Standards ◽  
Experimental Results ◽  
Electric Grid ◽  
Design Constraints ◽  
Lcl Filter ◽  
Current Harmonics ◽  
Three Phase

Compensators are devices which diminish the current harmonics of the lower order which are injected to the electric grid to meet the international standards. Resonant compensators are used to reduce the particular harmonics in grid-connected photovoltaic inverters. This paper presents how the harmonics are mitigated within the standards by using lead, lag, lead-lag compensators. The frequency deviation and transient response are considered the important factors during the design of the compensators. MATLAB design of grid connected photovoltaic inverter is presented with simulation result. A hardware of three phase photovoltaic load connected inverter with LCL filter was implemented. The simulation and experimental results of Grid connected Photovoltaic inverter with and without compensation are discussed. The harmonic profiles of these compensators are also presented.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

scholarly journals Geometric Algebra Framework Applied to Symmetrical Balanced Three-Phase Systems for Sinusoidal and Non-Sinusoidal Voltage Supply

Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1259
Author(s):  
Francisco G. Montoya ◽  
Raúl Baños ◽  
Alfredo Alcayde ◽  
Francisco Manuel Arrabal-Campos ◽  
Javier Roldán Roldán Pérez
Keyword(s):  
Geometric Algebra ◽  
Dimensional Euclidean Space ◽  
Active Components ◽  
Electrical Circuits ◽  
Current Harmonics ◽  
Operation Conditions ◽  
Multiple Phase ◽  
Three Phase ◽  
Phase Systems ◽  
Definition Of

This paper presents a new framework based on geometric algebra (GA) to solve and analyse three-phase balanced electrical circuits under sinusoidal and non-sinusoidal conditions. The proposed approach is an exploratory application of the geometric algebra power theory (GAPoT) to multiple-phase systems. A definition of geometric apparent power for three-phase systems, that complies with the energy conservation principle, is also introduced. Power calculations are performed in a multi-dimensional Euclidean space where cross effects between voltage and current harmonics are taken into consideration. By using the proposed framework, the current can be easily geometrically decomposed into active- and non-active components for current compensation purposes. The paper includes detailed examples in which electrical circuits are solved and the results are analysed. This work is a first step towards a more advanced polyphase proposal that can be applied to systems under real operation conditions, where unbalance and asymmetry is considered.

scholarly journals Hybrid Three-Phase Rectifiers with Active Power Factor Correction: A Systematic Review

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1520
Author(s):  
José Teixeira Gonçalves ◽  
Stanimir Valtchev ◽  
Rui Melicio ◽  
Alcides Gonçalves ◽  
Frede Blaabjerg
Keyword(s):  
Power Factor ◽  
Power Distribution ◽  
Harmonic Distortion ◽  
International Standards ◽  
Pwm Converter ◽  
High Power Factor ◽  
Three Phase ◽  
Sinusoidal Input ◽  
Converter Topologies ◽  
Future Direction

The hybrid three-phase rectifiers (HTR) consist of parallel associations of two rectifiers (rectifier 1 and rectifier 2), each one of them with a distinct operation, while the sum of their input currents forms a sinusoidal or multilevel waveform. In general, rectifier 1 is a GRAETZ (full bridge) (can be combined with a BOOST converter) and rectifier 2 is combined with a DC-DC converter. In this HTR contest, this paper is intended to answer some important questions about those hybrid rectifiers. To obtain the correct answers, the study is conducted as an analysis of a systematic literature review. Thus, a search was carried out in the databases, mostly IEEE and IET, and 34 papers were selected as the best corresponding to the HTR theme. It is observed that the preferred form of power distribution in unidirectional hybrid three-phase rectifiers (UHTR) is 55%Po (rectifier 1) and 45%Po (rectifier 2). For the bidirectional hybrid three-phase rectifiers (BHTR), rectifier 1 preferably takes 90% of Po and 10% of Po is processed by rectifier 2. It is also observed that the UHTR that employ the single-ended primary-inductor converter (SEPIC) or VIENNA converter topologies in rectifier 2 can present sinusoidal input currents with low total harmonic distortion (THD) and high Power Factor (PF), even successfully complying with the international standards. The same can be said about the rectifier that employs a pulse-width (PWM) converter of BOOST topology in rectifier 2. In short, the HTR are interesting because they allow using the GRAETZ full bridge topology in rectifier 1, thus taking advantage of its characteristics, being simple, robust, and reliable. At the same time, the advantages of rectifier 2, i.e., high PF and low THD, are well used. In addition, this article also points out the future direction of research that is still unexplored in the literature, thus giving opportunities for future innovation.

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