Lesław Gołębiowski, Marek Gołębiowski, Damian Mazur and Andrzej Smoleń
The purpose of this paper is to compare the methods of calculating the parameters of air-cored stator flux permanent magnet generator and to compare these results with the…
Abstract
Purpose
The purpose of this paper is to compare the methods of calculating the parameters of air-cored stator flux permanent magnet generator and to compare these results with the measurements of the designed and manufactured generator. The generator is to be designed for operation in a wind power plant.
Design/methodology/approach
An analytical method and 2D and 3D finite element methods (FEMs) were used to calculate the parameters of the coreless permanent magnet axial generator. The analytical method and 2D FEM were applied to individual cross-sections through the air gap of the machine. After the design and construction of the generator and measuring station, the results of calculations and measurements were compared.
Findings
The results of investigated calculation methods and measurements were found to be mutually compatible. Analytical methods and 2D FEM required proper interpretation of the results when comparing them with the 3D FEM. The results of the measurements and calculations showed the usefulness of the generator for operation in a wind power plant.
Originality/value
Full comparison of results of 2D and 3D calculations with the results of the measurements on the machine model confirmed the usefulness of fast 2D methods for the analysis of coreless generators. The results differed by the effects of leakage inductance of windings’ front connections. The application of an axial generator designed with the described methods in a wind turbine showed its proper operation.
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Keywords
Lesław Gołębiowski, Marek Gołębiowski and Damian Mazur
The aim of this paper is to develop the method of optimal control of the three‐phase inverter system for autonomous and power grid operation. The presented method will also allow…
Abstract
Purpose
The aim of this paper is to develop the method of optimal control of the three‐phase inverter system for autonomous and power grid operation. The presented method will also allow the cooperation of several inverters creating an autonomous network. This system should also be able to reduce demanded higher harmonics in power voltage according to the list of numbers of these harmonics. In this article the authors describe a system that is used to create a symmetrical three‐phase voltage. The supply power is taken from the renewal source. The inverter system as well as cooperation of several such systems to create an autonomous network is under consideration. The generated three‐phase voltage should be symmetrical even when the RL load is not symmetrical or else it changes in impulse. Cooperation of the system with the autonomous network is also under consideration. The task is to supply the set current of the basic harmonic to the power grid and possibly to reduce voltage higher harmonics on output terminals of the system.
Design/methodology/approach
The method of optimal control for a quadratic objective function was applied.
Findings
In the autonomous system the presented method provides a symmetrical three‐phase voltage with an unknown unsymmetrical constant or pulsed load. When operating for a power grid the system provides the desired current related to the basic harmonic of the grid voltages. In both cases the demanded higher harmonics of the grid voltages are reduced.
Originality/value
Filter of the main harmonic for the power grid voltage was applied. Applied numerical solutions and obtained simulations are also original.
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Michał Mazur, Roman Pastuszek, Damian Wojcieszak, Danuta Kaczmarek, Jarosław Domaradzki, Agata Obstarczyk and Aneta Lubanska
Indium tin oxide (ITO) is a material belonging to the group of transparent conductive oxides, which are widely used in many fields of technology including optoelectronics and…
Abstract
Purpose
Indium tin oxide (ITO) is a material belonging to the group of transparent conductive oxides, which are widely used in many fields of technology including optoelectronics and photovoltaics. However, the properties of ITO thin films depend on many factors. Therefore, the aim of the study was thorough investigation of the properties of sputtered ITO thin films of various thicknesses.
Design/methodology/approach
ITO coatings were deposited by magnetron sputtering in pure argon atmosphere using ceramic ITO target. Various deposition times resulted in obtaining thin films with different thickness, which had significant influence on the optoelectronic properties of deposited coatings. In this work the results of investigation of structural, surface, optical and electrical properties were presented.
Findings
Increase of the coating thickness caused change of the microstructure from amorphous to nanocrystalline and occurrence of grains with a size of 40 to 60 nm on their surface. Moreover, the fundamental absorption edge was red-shifted, whereas the average transmission in the visible wavelength range remained similar. Increase of the thickness caused considerable decrease of the sheet resistance and resistivity. It was found that even thin films with a thickness of 10 nm had antistatic properties.
Originality/value
The novelty and originality of presented work consists in, among other, determination of antistatic properties of ITO thin films with various sheet resistances that are in the range typical for dielectric and semiconducting material. To date, there are no reports on such investigations in the literature. Reported findings might be very helpful in the case of, for example, construction of transparent antireflective and antistatic multilayers.