Design of Linear and Nonlinear Controllers for a Grid-Connected PV System for Constant Voltage Applications

2020 ◽  
pp. 149-179
Author(s):  
Nibedita Swain ◽  
Nivedita Pati
Keyword(s):  
Constant Voltage ◽  
Pv System ◽  
Nonlinear Controllers ◽  
Linear And Nonlinear

scholarly journals Linear and nonlinear controllers of a solar photovoltaic water pumping system

2020 ◽  
Vol 9 (5) ◽  
pp. 1861-1872
Author(s):  
M. Madark ◽  
A. Ba-razzouk ◽  
M. El Malah
Keyword(s):  
Mathematical Model ◽  
Induction Motor ◽  
Centrifugal Pump ◽  
Solar Photovoltaic ◽  
Rotor Speed ◽  
Control Laws ◽  
Pumping System ◽  
Water Pumping ◽  
Nonlinear Controllers ◽  
Linear And Nonlinear

This paper provided a comparative study between linear and nonlinear controllers of a solar photovoltaic (PV) water pumping system using an induction motor and a centrifugal pump. For linear controller, classical Perturb and Observe was selected to ensure the operation of the PV system at the maximum power point (MPP) and is combined with Indirect Rotor Field Oriented Control (IRFOC) based on a conventional proportional integral speed regulator chosen to control and to optimize the rotor speed. In second and third controllers, Backstepping and first order sliding mode controls were proposed for controlling the whole system. To regulate and optimize rotor speed in the nonlinear controller, all considered control techniques were combined with IRFOC in order to establish easy control laws. In addition, MPP was tracked by acting on the DC-DC converter and using its mathematical model for developing control laws. Maximum delivered power was used as reference signal for optimizing actual rotor speed. The controlled system is operated without mechanical sensors. Estimators of rotor speed and load torque were proposed based on the mathematical model of induction motor and centrifugal pump and using only available output measurements.. Simulation results were investigated and the effectiveness of the nonlinear proposed strategies.

scholarly journals Supertwisting Sliding Mode Algorithm Based Nonlinear MPPT Control for a Solar PV System with Artificial Neural Networks Based Reference Generation

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3695 ◽  
Author(s):  
Shahzad Ahmed ◽  
Hafiz Mian Muhammad Adil ◽  
Iftikhar Ahmad ◽  
Muhammad Kashif Azeem ◽  
Zil e Huma ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Environmental Conditions ◽  
Peak Power ◽  
Sliding Mode ◽  
Maximum Power ◽  
Sliding Mode Controller ◽  
Pv System ◽  
Maximum Power Point ◽  
Nonlinear Controllers ◽  
Power Point

The problem of extracting maximum power from a photovoltaic (PV) system with negligible power loss is concerned with the power generating capability of the PV array and nature of the output load. Changing weather conditions and nonlinear behavior of PV systems pose a challenge in tracking of varying maximum power point. A robust nonlinear controller is required to ensure maximum power point tracking (MPPT) by handling nonlinearities of a system and making it robust against changing environmental conditions. Sliding mode controller is robust against disturbances, model uncertainties and parametric variations. It depicts undesirable phenomenon like chattering, inherent in it causing power and heat losses. In this paper, a supertwisting sliding mode algorithm based nonlinear robust controller has been designed for MPPT of a PV system which not only removes the chattering but also enhances the overall system’s dynamic response. Moreover, supertwisting sliding mode controller is robust against changing environmental conditions like change in temperature and irradiance. Noninverting DC-DC Buck-Boost converter has been used as an interface between source and the load. The efficiency of MPPT of a PV system depends upon the accuracy of reference for peak power voltage, therefore an efficient mechanism for reference generation has also been proposed in this work. The reference for peak power voltage has been generated by using a trained artificial neural network, which is to be tracked by proposed nonlinear controllers. Sliding mode controller (SMC) and synergetic controllers have also been designed for MPPT of a PV system in order to compare them with supertwisting sliding mode controller (ST-SMC). Global asymptotic stability of the system has been ensured by using Lyapunov stability criterion. The performance of the proposed nonlinear controllers has been validated in MATLAB/Simulink ODE 45 environment. ST-SMC has also been compared with recently proposed integral backstepping controller and other conventional MPPT controllers given in the literature. The simulation results show the better performance of ST-SMC in terms of best dynamic response and robustness.

On Fuzzy Control of Chaotic Systems

2004 ◽  
Vol 10 (7) ◽  
pp. 979-993 ◽  
Author(s):  
Ahmad M. Harb ◽  
Issam A. Smadi
Keyword(s):  
Mathematical Model ◽  
Fuzzy Logic ◽  
Fuzzy Control ◽  
Power Systems ◽  
Strange Attractor ◽  
Chaotic Systems ◽  
Chaotic Behavior ◽  
Secure Communications ◽  
Nonlinear Controllers ◽  
Linear And Nonlinear

In this paper, we introduce the control of the strange attractor, chaos. Because of the importance of controlling undesirable behavior in systems. researchers are investigating the use of linear and nonlinear controllers, either to remove such oscillations (in power systems) or to match two chaotic systems (in secure communications). The idea of using the fuzzy logic concept for controlling chaotic behavior is presented. There are two good reasons for using fulzy control: first, there is no mathematical model available for the process; secondly. it can satisfy nonlinear control that can be developed empirically. without complicated mathematics. The two systems are well-known models so the first reason is not a big problem. and we can take advantage of the second reason.

Research on Grid-Connected and Off-Grid Switching Distributed Photovoltaic Power System

2014 ◽  
Vol 953-954 ◽  
pp. 24-28
Author(s):  
Xian Kui Wen ◽  
Yong Xiao ◽  
Shi Jun Chen ◽  
Jun Liu
Keyword(s):  
Power System ◽  
Frequency Control ◽  
Constant Voltage ◽  
Pv System ◽  
The Public ◽  
Public Supply ◽  
Grid Connection ◽  
Photovoltaic Power ◽  
Voltage Frequency ◽  
Grid Operation

Photovoltaic power system (PV system) includes grid-connected and off-grid (islanding) types. With the improvement of power supply reliability, it is necessary to provide distributed PV power system with functions of grid-connection and off-grid operation, which as well as being easily switched. This research comparative analyzes on model of AC bus and model of DC bus of grid-connected and off-grid PVsystem and presents the control strategy. In order to safely operate and seamlessly switch grid-connected and off-grid, PV system is furnised constant-power control and constant-voltage frequency control with switching operation. Additionally, the switch junction for off-grid and the public supply system must be connected to the synchronization device for controling system of PV system therefore the PV system can be safely operated and switch from off-grid to grid-connected can be smoothly and rapidly.

Electrified coating flows on vertical fibres: enhancement or suppression of interfacial dynamics

2013 ◽  
Vol 735 ◽  
pp. 427-456 ◽  
Author(s):  
A. W. Wray ◽  
D. T. Papageorgiou ◽  
O. K. Matar
Keyword(s):  
Fluid Layer ◽  
Asymptotic Methods ◽  
System Of Equations ◽  
Constant Voltage ◽  
Coating Flows ◽  
Long Wave ◽  
Linear And Nonlinear ◽  
Concentric Electrode ◽  
Nonlinear Regimes ◽  
Viscous Stresses

AbstractWe investigate the evolution and stability of a wetting viscous fluid layer flowing down the surface of a cylinder, and surrounded by a conductive gas. The inner cylinder is an electrode kept at constant voltage, and a second, concentric electrode encloses the system whose potential is allowed to vary spatially. This induces electrostatic forces at the interface in competition with surface tension and viscous stresses. Asymptotic methods are used to derive a long-wave axisymmetric model governing the interfacial position and charge density. The resulting system of equations is investigated both analytically and numerically to determine its stability characteristics in the linear and nonlinear regimes.

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