Adel M. Sharaf

A Photovoltaic Array Simulation Model for Matlab-Simulink GUI Environment

A photovoltaic array (PVA) simulation model to be used in Matlab-Simulink GUI environment is developed and presented in this paper. The model is developed using basic circuit equations of the photovoltaic (PV) solar cells including the effects of solar irradiation and temperature changes. The new model was tested using a directly coupled dc load as well as ac load via an inverter. Test and validation studies with proper load matching circuits are simulated and results are presented here.

A novel on-line MPP search algorithm for PV arrays

A novel maximum power point (MPP) search algorithm for photovoltaic (PV) array power systems is introduced. The proposed algorithm determines the maximum power point of a PV array for any temperature and solar irradiation level using an online procedure. The method needs only the online values of the PV array output voltage and current, which can be obtained easily by using just current and voltage transducers. The algorithm requires neither the measurement of temperature and solar irradiation level nor a PV array model that is mostly used in look-up table based algorithms. Satisfactory results were obtained with the proposed algorithm in a laboratory prototype implementation scheme consisting of a PV array computer emulation model, a chopper controlled permanent magnet DC motor, and a DT2827 data acquisition board with the ATLAB software drivers for interfacing.

A fuzzy logic power tracking controller for a photovoltaic energy conversion scheme

Abstract The maximum solar power tracking and energy utilization of a stand-alone photovoltaic array (PVA) feeding a chopper controlled permanent magnet DC motor drive scheme is studied. A computer controlled model of the PVA including the effects of temperature and solar irradiation changes was developed and used in both digital simulation and laboratory implementation. The electrical load applied voltage was controlled by a MOSFET type-A chopper using either proportional-integral or fuzzy logic based controllers so that the maximum available solar power of the pVA is always tracked for all varying ambient temperature and solar irradiation levels, as well as for any small variations of the electrical load. The dynamic performance of the overall system was studied and satisfactory results were obtained using both types of controller.

A Novel Modulated Power Filter Compensator for Distribution Networks with Distributed Wind Energy

During the last two decades, renewable wind energy has become increasingly popular as a consequence of strong ecological concerns and appealing advantages with regard to economical energy solutions in remote communities. Furthermore, with very large wind farms emerging, the dispersed renewable wind energy is required to be fully connected to the electrical distribution networks. However, the integration of dispersed renewable wind energy will pose a great challenge to the power quality in the distribution networks when the weak nature of the grid in remote areas and the uncertainty of wind are taken into consideration.This paper presents a novel Modulated Power Filter Compensator (MPFC) for the distribution networks with dispersed renewable wind energy interfaced. A tri-loop error driven controller is used to adjust the PWM switching of the modulated power filter compensator. Full power factor correction and power quality improvement is validated under different operation conditions, like load switching and wind velocity excursions. The MPFC device is a member of novel FACTS based compensators developed by the first author.

Flicker control using rule based modulated passive power filters

Abstract The paper presents a novel modulated passive power filter scheme for nonlinear load bus voltage flicker control using an error-driven. error-scaled rule based controller for online voltage stabilization.

Novel STATCOM Controllers for Voltage Stabilization of Stand Alone Hybrid (Wind/Small Hydro) Schemes

This paper presents Three novel error driven dynamic controllers for the Static Synchronous Compensator (STATCOM) Facts device to stabilize both Wind Energy Conversion stand alone systems (SWECS) as well as hybrid scheme of wind plus small hydro with employing self excited induction generator. The unified AC system of standalone wind energy conversion scheme and hybrid wind/small hydro scheme are connected to a hybrid electric load. Three novel error driven dynamic controllers are validated for the STATCOM as a voltage stabilization scheme. Two novel controller are error driven dynamic controllers with auxiliary tracking control loop. The first controller is tri loop dynamic error driven controller using the RMS Load bus voltage, RMS-Load Current and the instantaneous AC load power. The second controller is DC voltage dynamic tracking controller using the dc link capacitor voltage. The third dynamic controller is based on the decoupled (d-q) current control strategy, namely the direct and quadrature current component for the STATCOM current. The dynamic response results demonstrated the effectiveness of the STATCOM-Facts device in stabilizing both AC wind energy system and the hybrid wind/hydro scheme by ensuring effective generator/load bus voltage regulation and dynamic reactive power compensation under load, wind and other prime mover excursions.

A novel discrete multi-objective Particle Swarm Optimization (MOPSO) of optimal shunt power filter

In this paper, a novel discrete optimization approach is developed to optimally solve the optimization problem of power system shunt filter design based on Discrete Multi Objective Particle Swarm Optimization MOPSO technique to ensure harmonic current reduction and noise mitigation on electrical utility grid. In this novel optimization approach, Multi Objective Particle Swarm Optimization MOPSO is implemented to tackle a number of conflicting goals that define the optimality problem. This paper deals with three conflicting objective functions. These conflicting functions are: 1. Minimum harmonic current penetration into the electric grid system, 2. Maximum harmonic current absorption by the harmonic power filter, 3. Minimum harmonic voltage distortion at the point of common coupling, Throughout the optimization process, all power filter parameters are being treated as either continuous or discrete variables. The shunt power filter design and optimization is performed over a specified set of discrete dominant offending harmonics.

A novel hybrid integrated wind-PV micro co-generation energy scheme for village electricity

A hybrid wind/PV system for supplying an isolated small community with electrical energy is digitally simulated and presented in this paper. The proposed hybrid renewable green energy scheme has four key subsystems or components to supply the required electric loads. The first subsystem includes the renewable generation sources from PV array and wind turbine. The second is the interface converters used to connect the renewable energy generators to the common DC collection bus, where all generated energy is collected. The third device represents the added inverter between the common collection DC bus and the added AC bus interface to feed all AC loads. The fourth subsystem comprises all controllers including the modulated power filter. The controller main function is to ensure efficient energy utilization and dynamic matching between loads and green energy generation as well as voltage stabilization. The proposed controllers are coordinated dynamic error driven PI regulators to control the interface converters. The integrated hybrid green energy system with key subsystems are digitally simulated using the Matlab/Simulink/Sim-Power software environment and fully validated for efficient energy utilizations and enhanced interface power quality under different operating conditions and load excursions.

A Novel Voltage Stabilization Control Scheme for Stand-alone Wind Energy Conversion Systems

This paper proposes a novel low cost FACTS based voltage stabilization scheme for a stand-alone wind energy conversion systems using self excited squirrel-cage induction generator (SEIG) driven by a wind turbine and interfaced to electric load. The new control scheme is designed not only to ensure bus voltage stabilization, but also to improve energy utilization using a low-cost PWM-switched modulated power filter compensator (MPFC) driven by a tri-loop dynamic error driven error scaled regulator. Numerous validation cases were simulated under different load types and excursions including linearized, motorized and nonlinear type loads. The proposed FACTS scheme is simulated and satisfactory results are obtained showing the applicability of the scheme for supplying electricity to remote areas such as isolated villages, heating, water pumping, ventilation and air conditioning.

A neuro-fuzzy hybrid power system stabilizer

Abstract The paper presents a novel neuro-fuzzy hybrid power system stabilizer (PSS) design for damping electromechanical modes of oscillation and enhancing power system synchronous stability. The hydrid PSS comprises a front-end conventional analog PSS design, an artificial neural network (ANN) based stabilizer, and a fuzzy logic post-processor gain scheduler. The stabilizing action is controlled by the post-processor gain scheduler based on an optimized fuzzy logic excursion based criterion J0. The two PSS stabilizers, conventional and neural network, have their damping action scaled online by the magnitude of J0 and its rate of change dJ0. The ANN feedforward two-layer based PSS design is the curve fitted nonlinear mapping between the damping vector signals and the desired optimized PSS output and is trained using the benchmark analog PSS conventional design. The fuzzy logic gain scheduling post-processor ensures adequate damping for large excursions, fault conditions, and load rejections. The parallel operation of a conventional PSS and a neural network PSS provides optimal sharing of the damping action under small as well as large-scale generation-load mismatch or variations in external network topology due to fault or switching conditions.