Design and Application of Electrical Machines

Electrical machines are one of the most important components of the industrial world. They are at the heart of the new industrial revolution, brought forth by the development of electromobility and renewable energy systems. Electric motors must meet the most stringent requirements of reliability, availability, and high efficiency in order, among other things, to match the useful lifetime of power electronics in complex system applications and compete in the market under ever-increasing pressure to deliver the highest performance criteria. Today, thanks to the application of highly efficient numerical algorithms running on high-performance computers, it is possible to design electric machines and very complex drive systems faster and at a lower cost. At the same time, progress in the field of material science and technology enables the development of increasingly complex motor designs and topologies. The purpose of this Special Issue is to contribute to this development of electric machines. The publication of this collection of scientific articles, dedicated to the topic of electric machine design and application, contributes to the dissemination of the above information among professionals dealing with electrical machines

Design and determination of stator geometry for axial flux permanent magnet free rod rotor synchronous motor

During designing a new axial flux permanent magnet free rod rotor synchronous motor, it is important to know before hand in which phase the largest angular velocity can occur, what is the ways to reduce the power consumption, how to achieve to increase or decrease the rotation speed by changing the core geometry. Therefore, presenting these preliminary information that are necessary for the design of a free rod rotor synchronous motor to the researchers is the aim of this work. In this respect, this study presents the design and geometrical dimensions of the stator for a new synchronous motor which is an axial flux permanent magnet free rod machine with three, four, five and six phases. This type of motors are an innovative approach especially for the applications used in industrial stirrers. Each type of stator is designed such that it has an appropriate number of phases. The rotating magnetic field over the stator is established by a PIC based microcontroller feeding the interface circuit to the stator wounds. The maximum angular speeds of bar magnet rotors with four different lengths and masses are calculated theoretically and determined experimentally. In addition, the effects of the distance between the rotor and stator, the angular speed of the rotor within the limits of the operation, and the volume of the liquid to be stirred to the power applied are investigated. Furthermore, the effects of the lengths and angular speeds of the bar magnet rotors to the distance between the rotor and stator are determined. In the light of the information obtained and taking into account the power used, the most appropriate parameters and variables such as the stator geometry changing with the phase used, the length of rotor, the distance between the rotor and stator and the angular speeds of rotor are determined. © 2011 Elsevier Ltd. All rights reserved

Design and integration of a dynamic IPT system for automotive applications

Inductive power transmission (IPT) for electric vehicles (EVs) is a promising emergent technology that seems able to improve the electric mobility acceptance. In the last two decades many researchers have proved its feasibility and the possibility to use it to replace the common conductive systems for the charge of the on-board battery. Many efforts are currently aimed to extend the IPT technology towards its use for the charge during the vehicle motion. This application, commonly indicated as dynamic IPT, is aimed to overcome the limit represented by the long stops needed for the recharge introducing also the possibility of reducing the battery capacity installed on vehicle. An IPT system is essentially based on the resonance of two magnetically coupled inductors, the transmitter, placed on or under the ground, and the receiver, placed under the vehicle floor. The typical operating frequency range for the EVs application goes from 20 kHz to approximately 100 kHz. The coupling between the two inductors takes place through a large air-gap, usually about 10-30 cm. This thesis presents the results of the research activities aimed to the creation of a prototype for the dynamic IPT oriented to the private transport. Starting from an analysis of the state of the art and the current research projects on this domain, this work presents the development of a circuit model able to describe the electromagnetic phenomena at the base of the power transfer and the interface with the power electronics. This model provides the information at the base of the design and the implementation of a dedicated low cost-high effciency H-bridge converter for the supply of the transmitter side. A general architecture of the power electronics that manages the receiver side is proposed together with the additional protection circuits. A methodology for the integrated design of the magnetic structure is illustrated covering the aspects of the matching with the power electronics, the integration on an existing vehicle and the installation on the road infrastructure. A series of activities aimed to the implementation of a dedicated test site are presented and discussed. In particular, the activities related to the creation of the electrical infrastructure and the issues and methods for the embedding of the transmitters in the road pavement are presented. The final goal is the creation of a dedicated IPT charging line one hundred meters long. Finally, a methodology for the assessment of the human exposure is presented and applied to the developed solution

EXPERIMENTAL ACTIVITY AND ANALYSIS OF PLC TECHNOLOGY IN VARIOUS SCENARIOS

Power line communications (PLCs) have become a key technology in the telecommunication world, both in terms of stand-alone technology or a technology that can complement other systems, e.g., radio communications. Since PLCs exploit the existing power delivery grid to convey data signals, the application scenarios are multiple. Historically, PLCs have been deployed in outdoor low voltage (< 1 kV) power distribution networks for the automatic metering and the management of the loads. Today, the evolution of the electrical grid toward an intelligent and smart grid that dynamically manages the generation, the distribution and the consumption of the power makes this technology still relevant in this scenario. Therefore, PLCs have raised significant interest in recent years for the possibility of delivering broadband Internet access and high speed services to homes and within the home. The increase in demand for such services has inspired the research activity in the in-home scenario, both toward the direction of the development of independent or integrated solutions, with respect to already existing technologies. Another application scenario that has not been deeply investigated yet is the in-vehicle one, which includes the in-car, in-plane and in-ship scenario. Since the power grid has not been designed for data communications, the transmission medium is hostile and exhibits high attenuation, multipath propagation and frequency selectivity, due to the presence of branches, discontinuities and unmatched loads. For the proper design of a power line communication (PLC) system, good knowledge of the grid characteristics in terms of propagation channel and disturbances is required. In this respect, we have performed experimental measurement campaigns in all the aforementioned scenarios. We aimed to investigate the grid characteristics from a telecommunication point of view. In this thesis, we present the results of our experimental activity. Firstly, we analyze the outdoor low voltage and industrial scenario. We have carried out a measurement campaign in an artificial network that can resemble either an outdoor low voltage power distribution network or an industrial or marine power system. We have focused on the channel frequency response, the line impedance and the background PLC noise, within the narrow band and the broad band frequency ranges. Then, we focus on the in-home scenario. In this context, we have studied the impact of the electrical devices (loads) connected to the power grid on the PLC medium characteristics and on the quality of the data communication. Their behavior has been investigated both in the time and frequency domain, in terms of load impedance and impulsive noise components that they inject into the network. Finally, we consider in-vehicle PLC, in particular the in-ship and in-car environment. Firstly, we summarize the results of a channel measurement campaign that we have carried out in a large cruise ship focusing on the low voltage power distribution network in the band 0-50 MHz. Thus, we present the results of an entire PLC noise and channel measurement campaign that we have performed in a compact electrical car

Elektromagnetische velden in arbeidssituaties

NB Nederlandstalige versie verschenen onder nummer 610015001N De EU heeft richtlijn 2004/40/EG uitgevaardigd om de werknemer te beschermen tegen gezondheidsrisico's door blootstelling aan elektromagnetische velden op het werk. Deze richtlijn moet uiterlijk 30 april 2008 zijn omgezet in nationale wetgeving. Ter voorbereiding hiervan heeft het RIVM in opdracht van het Ministerie van SZW de blootstelling in Nederlandse arbeidssituaties geinventariseerd en geanalyseerd. Het doel van dit rapport is de werkgevers een handreiking te geven om vast te stellen of aan de eisen uit de richtlijn wordt voldaan en om de risico-inventarisatie en -evaluatie (RI&E) voor elektromagnetische velden op te stellen. Totdat er geharmoniseerde Europese normen van het Europees Comiti voor elektrotechnische normalisatie (CENELEC) beschikbaar zijn voor alle situaties die moeten worden beoordeeld, gemeten en berekend, mag dit rapport als richtsnoer gebruikt worden. Gebruik van dit rapport is dus geen verplichting. Voor de meeste werkgevers is het voldoende om de eerste twee hoofdstukken door te nemen. De volgende drie hoofdstukken bevatten voor een aantal arbeidssituaties informatie over de blootstelling, de rekenregels waarmee de situatie kan worden ingeschat en de mogelijke beheersmaatregelen. Het laatste hoofdstuk geeft een overzicht van de kosten die met invoering van de richtlijn samenhangen. Om te kunnen toetsen of de blootstelling onder de limieten van de richtlijn blijft, moeten CENELEC-normen worden gebruikt, voor zover ze bestaan. Deze normen zijn zonder specialistische kennis niet eenvoudig toe te passen. Ook hoeft niet alle apparatuur even uitgebreid beoordeeld te worden of zijn even zware maatregelen nodig. Om de beoordeling te vergemakkelijken geeft dit rapport een beoordelingsschema en tabellen met een indeling van alle relevante werkomgevingen in drie categorieen. Voor iedere categorie geldt een ander beoordelingstraject.The EU has issued Directive 2004/40/EC on the protection of workers from health and safety risks arising from exposure to electromagnetic fields in the workplace. This directive must be implemented in national legislation no later than 30 April 2008. To prepare for implementation, RIVM has, on commission of the Ministry of Social Affairs and Employment, investigated and analysed the exposure in Dutch working environments. The purpose of this report is to provide assistance to employers to assess whether compliance is met and to carry out the inventory and evaluation of risks (RI&E) due to electromagnetic fields. Until harmonised European standards from CENELEC cover all relevant assessment, measurement and calculation situations, this report may serve as a guide. It is not mandatory to use this report. It will be sufficient for most of the employers to confine themselves to the first two chapters. Subsequent chapters deal with the exposure found in several working environments and provide guidelines for assessing risks and possible measures in these working environments. Costs for implementing the directive are discussed in the last chapter. CENELEC standards, if available, are mandatory for assessing whether exposure occurs below the limits in the directive. However, these standards are not easy to use without specialist knowledge. Furthermore, not all equipment needs to be assessed to the same extent nor are the same measures needed. A flow chart and tables of relevant working environments, classified into three categories, are provided to facilitate the assessment. Each category has its own assessment path.SZ

Lunar construction utility vehicle

The lunar construction utility vehicle (LCUV) is an all-purpose construction vehicle which will aid in the robotic assembly of a lunar outpost. The LCUV will have the following capabilities: (1) must be self supporting including repairs; (2) must offload itself from a lunar lander; (3) must be telerobotic and semi-autonomous; (4) must be able to transport one space station common module; (5) must allow for man-rated operation; and (6) must be able to move lunar regolith for site preparation. This study recommends the use of an elastic tracked vehicle. Detailed material analyses of most of the LCUV components were accomplished. The body frame, made of pinned truss elements, was stress analyzed using NASTRAN. A track connection system was developed; however, kinematic and stress analyses are still required. This design recommends the use of hydrogen-oxygen fuel cells for power. Thermal control has proven to be a problem which may be the most challenging technically. A tentative solution has been proposed which utilizes an onboard and towable radiator. Detailed study of the heat dissipation requirements is needed to finalize radiator sizing. Preliminary work on a man-rated cabin has begun; however, this is not required during the first mission phase of the LCUV. Finally, still in the conceptual phases, are the communication, navigation and mechanical arm systems

Digital Twin Techniques for Power Electronics-Based Energy Conversion Systems : A Survey of Concepts, Application Scenarios, Future Challenges, and Trends

The steady increase in energy demands has led to ever-increasing “energy generation.” This, coupled with the need for higher efficiency, flexibility, and reliability, has boosted the use of power electronics in power and energy systems. Therefore, power electronics-based energy conversion systems (PEECSs) have become prominent in power generation, power transmission, and end user applications. Given the relevance of such systems, and by considering their trend of digitalization, it is crucial to establish digital and intelligent PEECSs. To this end, digital twins (DTs) can be adopted, as they integrate many cuttingedge information techniques to realize the life cycle management of complex systems by constructing real-time mappings of them. In this article, existing DT techniques for PEECSs are reviewed. The concept, system layers, and key technologies of DTs are described first. Some application cases of DTs are then elaborated. Finally, future trends and challenges of DTs are discussed to provide a valuable reference for subsequent research.acceptedVersionPeer reviewe