scholarly journals Frequency-adaptive grid-virtual-flux synchronization by multiple second-order generalized integrators under distorted grid conditions

2015 ◽  
Vol 23 ◽  
pp. 1930-1945 ◽  
Author(s):  
Yingjie WANG ◽  
Haiyuan LIU ◽  
Xuelong HAN ◽  
Kangan WANG
Keyword(s):  
Adaptive Grid ◽  
Second Order ◽  
Distorted Grid ◽  
Virtual Flux

A novel second-order adaptive grid method for singularly perturbed convection–diffusion equations

2021 ◽  
Author(s):  
Xuqiong Luo ◽  
Na Yang ◽  
Qingshan Tong
Keyword(s):  
Truncation Error ◽  
Integral Transform ◽  
Grid Method ◽  
Adaptive Grid ◽  
Second Order ◽  
Singularly Perturbed ◽  
Local Truncation Error ◽  
Convection Diffusion ◽  
Grid Algorithm ◽  
Mesh Equidistribution

In this paper, a singularly perturbed convection–diffusion equation is studied. At first, the original problem is transformed into a parameterized singularly perturbed Volterra integro-differential equation by using an integral transform. Then, a second-order finite difference method on an arbitrary mesh is given. The stability and local truncation error estimates of the discrete schemes are analyzed. Based on the mesh equidistribution principle and local truncation error estimation, an adaptive grid algorithm is given. In addition, in order to calculate the parameters of the transformation equation, a nonlinear unconstrained optimization problem is constructed. Numerical experiments are given to illustrate the effectiveness of our presented adaptive grid algorithm.

scholarly journals New control scheme for synchronizationof a photovoltaic system to a three-phase grid to attenuate the harmonics of currents caused by distorted grid voltage

2020 ◽  
Vol 9 (3) ◽  
pp. 256
Author(s):  
Ismail Boukhechem ◽  
Ahcen Boukadoum ◽  
Lahcene Boukelkoul ◽  
Houssam Eddine Medouce ◽  
Rima Lebied
Keyword(s):  
Photovoltaic System ◽  
Pv System ◽  
Grid Voltage ◽  
Voltage Sensors ◽  
Distorted Grid ◽  
Three Phase ◽  
Control Scheme ◽  
Self Tuning ◽  
A New Technique ◽  
Virtual Flux

<div data-canvas-width="397.43840959483975">This study presents a new scheme of control for the synchronization of a photovoltaic (PV) system with a three-phase grid without a line sensor. The approach of the proposed synchronization technique is developed to extract the</div><div>maximum of PV energy and inject it in the network for various conditions of voltage, and to ensure that the currents injected into the three-phase network emulate the wished sinusoidal forms even when the mains grid voltage is no longer ideal. This paper in troduces a new technique of synchronization and elimination of the disturbances created by the distorted tension based on the direct power control without voltage sensors (VF_DPC) with the help of second-order generalized integrator (SOGI) associated with a self-tuning filter(STF) to extract the fundamental virtual flux. The simulation of the proposed system is realized in MATLAB/Simulink environment.</div>

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