Hegazy Rezk

A novel methodology for simulating maximum power point trackers using mine blast optimization and teaching learning based optimization algorithms for partially shaded photovoltaic system

When the photovoltaic (PV) system is fully illuminated, the voltage-power characteristic of the array has one maximum power point (MPP). This point can be tracked by conventional maximum power point tracker algorithms. On the other hand, in partially shaded PV, the voltage--power characteristic has only one global MPP (GMPP) and multiple local MPPs. It is important to operate the PV system at GMPP for achieving optimal operation. This paper presents the application of two novel meta-heuristic optimization algorithms to extract GMPP from the PV system under partial shading conditions: The mine blast algorithm (MBA) and the teaching learning based optimization algorithm (TLBO). A proposed constrained objective function representing the PV array output power is also presented. Different patterns of shadows that strike the PV array surface are studied. The studied patterns are uniform ones, changing from 0% to 375% with steps of 25%, and non-uniform patterns with different locations of GMPP. The obtained resu...

Performance of incremental resistance MPPT based proton exchange membrane fuel cell power system

A simple static PSIM model of proton exchange membrane fuel cell (PEMFC) stack has been developed in this article. The proposed model includes different losses occurred inside fuel cell (FC) like activation, ohmic, and concentration losses. It is flexible and user-friendly on simulation platform for design and implementation of FC. On the other hand, the tradeoff between steady state and dynamic performance of incremental resistance (INR) based maximum power point tracking (MPPT) for PEMFC stack power system is presented. The overall tracking performance of proposed tracker based fixed and variable step size perturbation in the boost converter duty cycle is analyzed and compared. Results revealed that variable step size based tracker enhance the tracking speed and overcome the steady state distortions simultaneously.

A comprehensive sizing methodology for stand-alone battery-less photovoltaic water pumping system under the Egyptian climate

Abstract This work introduces comprehensive sizing methodology to optimize a stand-alone battery-less PV water pumping system (PVWPS). The essential target for the battery-less PVWPS is storing water instead of electrical energy. The drawback of employing battery storage is requiring a complex control system. Accordingly it can considerably raise the cost and maintenance burdens of system. PV panel’s orientation has been investigated for achieving maximum incident radiation collected by PV panels at summer session, when large water quantity is demanded for irrigation purposes. The proposed technique is designed and is applied to estimate the optimal sizing of PVWPS for installing at Minya (Egypt). The obtained results demonstrated that, the PV panels should be horizontally oriented to achieve maximum collected energy during the season of peak water demand. Hence, the PV system offers much more water with a smaller PV cells area, i.e. lower cost of irrigation during summer season. This can be considered cost effective solution for agricultural purposes.

Robust parameter estimation of vector controlled induction motors based on a modified particle swarm optimization technique

Particle swarm optimization (PSO) technique has been integrated with sensorless field oriented control induction motor (FOC IM) drive system to identify its optimal parameters. The proposed PSO algorithm is run in parallel with sensorless FOC IM drive taking the stator current as input to estimate both electrical and mechanical parameters. Such parameters are stator resistance, rotor resistance, rotor inductance, magnetizing inductance and motor inertia. The electrical parameters are fed to a back emf model reference adaptive system (BMF MRAS) to estimate its rotor shaft angular speed. On the other hand, the effect of changing estimated parameters from their actual ones on the FOC IM performance has been carried out. Moreover, the estimated motor inertia is used to estimate load torque to avoid any undesirable disturbance. The estimated parameters are obtained from the minimization of a certain fitness function which is represented by the summation of errors between real and estimated quantities. Finally, a comparison between real and estimated motor parameters is conducted in order to demonstrate the accuracy of the proposed technique.