Ismail H. Altas

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.

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 Hybrid Photovoltaic PV Array-Battery Powered EV-PMDC Drive Scheme

In this study, a hybrid photovoltaic PV array-battery powered PMDC drive scheme is realized. The PID tri loop limited current loop controller with motor current of four-wheel drive electric vehicle is used. Photovoltaic array and DC motor model are obtained in the Simulink. The proposed system control mechanism is digitally simulated by using the MATLAB/ Simulink/Sim-Power Systems software. The dynamic performance of the system is brought into at the constant speed reference and the variable speed reference trajectory.

The effects of the number of rules on the output of a fuzzy logic controller employed to a PM d.c. motor

This paper investigates the effects of the number of the rules in a fuzzy logic controller (FLC). In addition, a novel approach to form the linguistic fuzzy subsets and fuzzy rule decision tables is also introduced. The proposed method to form the fuzzy rule tables is based on the comparison of possible transient responses of the controlled system output and the reference set point. The relationship between the number of fuzzy rules and the controlled output signal for a permanent magnet direct current (pmdc) motor circuit is investigated using a three-dimensional output expression. Since the relationship between the input and output is smooth, the effect of the number of the rules are negligible as long as they express a similar relationship. The sensitivity of the FLC with respect to variations in the rule decision tables is also tested by changing the original decision table values in the range of ±30%. It is observed that these variations in the rule decision tables do not cause any instability in the proposed fuzzy logic controller.

A real-time computer-controlled simulator: For control systems

A real‐time simulator to accompany automatic control system courses is introduced. The design and realization methods and processes are discussed. The simulator is basically a computer‐controlled system that implements the developed user friendly virtual interface software to control the speed of a small size DC motor. The virtual interface includes digital implementation models of classical proportional, integral, derivative, and all combinations of them as well as a fuzzy logic controller. The user is able to select and adjust the parameters of any desired controller that is defined and represented virtually.

A novel fuzzy logic tansigmoid controller for Wave Energy Converter-grid interface DC energy utilization farm

The paper presents a digital simulation and validation study of a novel control system for control of a Wave Energy Converter (WEC)-Battery renewable energy system for DC type loads. The performance and dynamic characteristics of the controllers to any load nonlinear J, B parameters and load torque is examined for PMDC Motor Drives. The proposed dynamic error driven control system is digitally simulated using the MATLAB/Simulink/SimPowerSystems software. The dynamic performance of the unified green energy Wave Energy-DC utilization system is examined for the proposed controller.

Novel STATCOM Controller for Reactive Power Compensation in Distribution Networks with Dispersed Renewable Wind Energy

This paper presents a novel multi-loop dynamic error driven controller based on the decoupled (d-q) voltage and current tracking loops for modulating the static synchronous compensator (STATCOM) used in distribution networks with dispersed renewable wind energy generation. The multi loop regulator adjusts the pulse switching pattern of the voltage-sourced converter (VSC) to ensure effective reactive power compensation and harmonic reduction. The effectiveness of the controller is fully validated under different operating conditions, like load switching and wind velocity excursions.