Modeling of Vertical Shaft Impact Crushers

One of the largest products in most civilized societies is concrete used to build various types of constructions. To create this product, a mixture of cement, chemical binders, and rock aggregates are combined and then poured into molds where it hardens. The sand part of the rock aggregates is either from natural sources or manufactured. Vertical shaft impact crushers can be used to create this machine sand but existing models make it hard to plan new sites and achieve a viable replacement to the natural sand.In this thesis, the use of vertical shaft impact crushers to crush aggregate rock to rounder particles is investigated. The main aim of this is to develop and further the understanding of the relationship between the machine and material properties with respect to the resulting crushed product in an effort to achieve an improved product. In order to gain a better understanding of the underlying mechanics of particle breakage, Discrete Element Method has been used to obtain particle collision energies. Several different product size distribution models have also been used to better predict the behavior of different crushers and feed sizes. To facilitate this, a framework to improve sites has been developed.The resulting framework simulates existing VSI machines and optimizes the machine parameters with respect to the specified feed material and PSD to create sought products. The framework can also be used to optimize existing sites which increases the effectiveness in terms of minimizing energy usage and waste products

Traction Motor for a Battery Electric City Bus - Specification and Drive Cycle Evaluation, Based on Comprehensive Data Collection

This internal, yet official, report serves as base for selecting the specification of a propulsion electric motor for a typical Battery Electric City Bus (BECB). The motor and the bus data are used as references in the research project Circular Economy for Electric Machines, sponsored by the Swedish Energy Agency. Additionally, found official bus drive cycles are presented and characterized, as well as four logs of real world driving of a battery electric city bus in Gothenburg, Sweden. Then, the energy consumption of the reference bus with the reference electric motor efficiency map are calculated and\ua0 compared to found official data on energy consumption of similar size battery electric city buses. Finally, related bus and electric bus market statistics and projections are summarized. In general, this report aim to provide background data for further analysis, which is why deeper analysis is left out of the report

Is villagisation an acceptable solution? - An analysis of villagisation programmes in Ethiopia in relation to the fulfilment of state obligations under the ICESCR and the concept of self-determination of indigenous people

The concept of ‘villagisation’ refers to the resettlement of people from scattered areas into villages, in order to ensure efficient control and to provide basic social services and infrastructure. This kind of governmental practice has been implemented in various regions in Africa throughout the years. The main objective of villagisation is to provide, or improve, access to basic economic and social services. The international human rights organisation, Human Rights Watch, has presented a line of reports concerning forced displacement of people, particularly highlighting the recent villagisation programme in Ethiopia. Because of villagisation in Ethiopia, large groups of indigenous people have been forced to move from their land and abandon their livelihood. Villagisation is a thus controversial concept, and evidence shows that states seriously fail to deliver in accordance with the objectives of the programmes. However, despite the failures states continue to implement these programmes. According to the International Covenant on Economic, Social and Cultural Rights (ICESCR) states shall use appropriate means to progressively realise the rights set forth in the Covenant. States must provide at least a minimum standard of the most basic rights. Villagisation could possibly be considered as an appropriate measure for developing states in order to fulfil the obligations under the ICESCR. However as states often fail to deliver in accordance with the aims of the programmes; it is questionable to whether villagisation really could be an acceptable solution in reality. One of the purposes of this thesis is to analyse whether villagisation, in view of the main official objectives of the programmes, could be considered as an appropriate measure for a developing country, such as to Ethiopia, to fulfil the state obligations under the ICESCR. According to international human rights, states have an obligation to protect the identity of indigenous people. The concept of indigenous people is however very controversial in Africa and in Ethiopia there is no official recognition of the concept. The identity of indigenous people is often associated with a specific territory as well as cultural practices and traditions. Because of villagisation, many indigenous peoples are forced to leave their homes and territories, with the risk of losing their identity. The right of self-determination is thus a very strong claim for indigenous people. The second purpose of this thesis is thus to analyse the possibility of indigenous people in Ethiopia to claim the right of self-determination in order to refuse to take part in villagisation programmes.”Villagisation" är ett koncept som innebär förflyttning eller omlokalisering av personer i utspridda bosättningsområden in till byar. Detta sker ofta i syfte att säkerställa en effektiv kontroll och att för att kunna tillhandahålla grundläggande samhällstjänster och infrastruktur. Denna typ av statliga program har genomförts i olika regioner i Afrika genom åren. Huvudsyftet med omförflyttningarna är just att tillhandahålla eller förbättra tillgången till grundläggande samhällstjänster. Den internationella människorättsorganisationen Human Rights Watch, har presenterat en rad rapporter som behandlar tvångsförflyttning av människor. Organisationen har särskilt belyst de senaste omlokaliseringsprojekten i Etiopien. På grund av dessa projekt har stora grupper av urfolk tvingats flytta från sin mark och överge sitt levebröd. Användandet av omlokaliseringsprogram, eller förflyttningsprogram, är kontroversiellt och allvarliga brister har även kunnat påvisas vad gäller ländernas uppfyllande av målen. Trots dessa brister är det många länder som fortsätter med aktiviteterna. Enligt den Internationella konventionen om de ekonomiska, sociala och kulturella rättigheterna, ska stater vidta lämpliga åtgärder för att successivt realisera de rättigheter som anges i Konventionen. Staterna måste åtminstone tillhandahålla en miniminivå av de mest grundläggande rättigheterna. Omlokaliseringsprojekt, kan mycket väl betraktas som lämpliga åtgärder för utvecklingsländer i syfte att uppfylla de skyldigheter som följer av Konventionen, men med tanke på att staterna ofta misslyckas med att leverera i enlighet med målen för programmen, kan det ifrågasättas huruvida detta är en godtagbar lösning i praktiken. Ett av syftena med denna uppsats är att analysera huruvida omlokaliseringsprogram, med sikte på de viktigaste officiella målen, skulle kunna betraktas som en lämplig åtgärd i ett utvecklingsland som t.ex. Etiopien, för att uppfylla statens skyldigheter i enlighet med Konventionen. I enlighet med internationella mänskliga rättigheter, har stater en skyldighet att skydda identiteten hos ursprungsbefolkningar. Frågan om urfolk är mycket kontroversiell i Afrika och i Etiopien finns det inget officiellt erkännande gällande dessa folks existens. Identiteten hos urfolken är ofta sammankopplad med ett visst landområde och kulturella sedvänjor och traditioner. På grund av omlokaliseringsprojekten, tvingas dock många grupper av ursprungsbefolkning att lämna sina hem och landområden, vilket kan medföra risk för att identiteten går förlorad. Kravet på självbestämmande är således mycket starkt hos urfolken. Det andra syftet med denna uppsats är att analysera möjligheten för urfolk i Etiopien att åberopa rätten till självbestämmande för att vägra att delta i de statliga omlokaliseringsprogrammen

Efficiency of Active Three-Level and Five-Level NPC Inverters Compared to a Two-Level Inverter in a Vehicle

This paper deals with a comparison of a standard two-level inverter, with a three-level and a five-level active neutral point clamped (ANPC) inverter for vehicle traction applications. The inverter efficiencies during different drive cycles are assessed and an efficiency enhancement of the multilevel inverters for partial loading and different drive cycle scenarios is found

BEV Powertrain Component Sizing With Respect to Performance, Energy Consumption and Driving Patterns

In this thesis, various drive cycles, legislative, official real-world and measured within the frame of the project, have been studied and characterized in terms of speed and acceleration cycle parameters, as well as acceleration and speed distribution. The objective was to assess typical vehicle usage on different road types, but also to study the implication on vehicle energy consumption due to the drive cycle’s characteristics. For this evaluation, three reference vehicles were designed after different set performance requirements, with data on existing BEVs as a frame of reference. An available traction motor, power electronic module and battery cell were utilized, where the motor was scaled by active length. Finally, the consequence of downsizing the electric drive system in terms of energy consumption and performance was also studied. Through comparison between legislative together with official real-world cycles and measured drive cycles, it was found that even though the measured cycles reach higher peak acceleration levels for a certain speed level, they still spend only slightly more time at higher levels of acceleration compared to the official cycles, at least on average over a group of similar cycles. During the powertrain sizing regarding torque and power, it turned out that the acceleration requirementwas dominating over other requirements such as top speed, and grade levels. The analysis shows that for two cycles with similar speed parameters such as maximum and average speed and time share at low speed, but where the speed time traces are very different with many more speed fluctuations in one cycle compared to the other, in combination with generally higher acceleration levels, the increase in net battery energy consumption per distancemay be as high as 28% for the cycle with more speed fluctuations. By down-scaling the electric drive system of the City car by 40%, the net battery energy per driven distance for low speed cycles increased by about 3−6%, while three of the cycles could not be fulfilled due to limited acceleration capability

Electromagnetic and Calorimetric Validation of a Direct Oil Cooled Tooth Coil Winding PM Machine for Traction Application

Tooth coil winding machines offer a low cost manufacturing process, high efficiency and high power density, making these attractive for traction applications. Using direct oil cooling in combination with tooth coil windings is an effective way of reaching higher power densities compared to an external cooling jacket. In this paper, the validation of the electromagnetic design for an automotive 600 V, 50 kW tooth coil winding traction machine is presented. The design process is a combination of an analytical sizing process and FEA optimization. It is shown that removing iron in the stator yoke for cooling channels does not affect electromagnetic performance significantly. In a previous publication, the machine is shown to be thermally capable of 25 A/mm2 (105 Nm) continuously, and 35 A/mm2 (140 Nm) during a 10 s peak with 6 l/min oil cooling. In this paper, inductance, torque and back EMF are measured and compared with FEA results showing very good agreement with the numerical design. Furthermore, the efficiency of the machine is validated by direct loss measurements, using a custom built calorimetric set-up in six operating points with an agreement within 0.9 units of percent between FEA and measured results

Fit-for-Purpose VSI Modelling Framework for Process Simulation

The worldwide shortage of natural sand has created a need for improved methods to create a replacement product. The use of vertical shaft impact (VSI) crushers is one possible solution, since VSI crushers can create particles with a good aspect ratio and smooth surfaces for use in different applications such as in construction. To evaluate the impact a VSI crusher has on the process performance, a more fit-for-purpose model is needed for process simulations. This paper aims to present a modelling framework to improve particle breakage prediction in VSI crushers. The model is based on the theory of energy-based breakage behavior. Particle collision energy data are extracted from discrete element method (DEM) simulations with particle velocities, i.e., rotor speed, as the input. A selection–breakage approach is then used to create the particle size distribution (PSD). For each site, the model is trained with two datasets for the PSDs at different VSI rotor tip speeds. This allows the model to predict the product output for different rotor tip speeds beyond the experimental configurations. A dataset from 24 different sites in Sweden is used for training and validating the model to showcase the robustness of the model. The model presented in this paper has a low barrier for implementation suitable for trying different speeds at existing sites and can be used as a replacement to a manual testing approach

Battery Modeling and Parameter Extraction for Drive Cycle Loss Evaluation of a Modular Battery System for Vehicles Based on a Cascaded H-Bridge Multilevel Inverter

This article deals with the modeling and the parameterization of the battery packs used in cascaded H-bridge multilevel propulsion inverters. Since the battery packs are intermittently conducting the motor currents, the battery cells are stressed with a dynamic current containing a substantial amount of low-order harmonic components up to a couple of kHz, which is a major difference in comparison to a traditional two-level inverter drive. Different models, such as pure resistive and dynamic RC -networks, are considered to model the energy losses for different operating points (OPs) and driving cycles. Using a small-scale setup, the models’ parameters are extracted using both a low-frequency, pulsed current, and an electrochemical impedance spectroscopy (EIS) sweep. The models are compared against measurements conducted on the small-scale setup at different OPs. Additionally, a drive cycle loss comparison is simulated. The simple resistive model overestimates the losses by about 20% and is, thus, not suitable. The dynamic three-time-constant model, parameterized by a pulsed current, complies with the measurements for all analyzed OPs, especially at low speed, with a maximum deviation of 3.8%. Extracting the parameters using an EIS seems suitable for higher speeds, though the losses for the chosen OPs are underestimated by 1.5%–7.9%

A scalable life cycle inventory of an electrical automotive traction machine—part I: design and composition

Purpose: A scalable life cycle inventory (LCI) model of a permanent magnet electrical machine, containing both design and production data, has been established. The purpose is to contribute with new and easy-to-use data for LCA of electric vehicles by providing a scalable mass estimation and manufacturing inventory for a typical electrical automotive traction machine. The aim of this article (part I of two publications) is to present the machine design, the model structure, and an evaluation of the models’ mass estimations. Methods: Data for design and production of electrical machines has been compiled from books, scientific papers, benchmarking literature, expert interviews, various specifications, factory records, and a factory site visit. For the design part, one small and one large reference machine were constructed in a software tool, which linked the machines’ maximum ability to deliver torque to the mass of its electromagnetically active parts. Additional data for remaining parts was then gathered separately to make the design complete. The two datasets were combined into one model, which calculates the mass of all motor subparts from an input of maximum power and torque. The range of the model is 20–200 kW and 48–477 Nm. The validity of the model was evaluated through comparison with seven permanent magnet electrical traction machines from established brands. Results and discussion: The LCI model was successfully implemented to calculate the mass content of 20 different materials in the motor. The models’ mass estimations deviate up to 21% from the examples of real motors, which still falls within expectations for a good result, considering a noticeable variability in design, even for the same machine type and similar requirements. The model results form a rough and reasonable median in comparison to the pattern created by all data points. Also, the reference motors were assessed for performance, showing that the electromagnetic efficiency reaches 96–97%. Conclusions: The LCI model relies on thorough design data collection and fundamental electromagnetic theory. The selected design has a high efficiency, and the motor is suitable for electric propulsion of vehicles. Furthermore, the LCI model generates representative mass estimations when compared with recently published data for electrical traction machines. Hence, for permanent magnet-type machines, the LCI model may be used as a generic component estimation for LCA of electric vehicles, when specific data is lacking

Thermal capability of electric vehicle PMSM with different slot areas via thermal network analysis

In this paper, the effect that a varied stator slot size has on the efficiency and thermal capability of a permanent magnet synchronous machine for an electric vehicle, is evaluated and quantified. A machine with four differently sized slot areas was electromagnetically evaluated with finite element analysis, and thermally with a lumped parameter network model. By decreasing the slot size while keeping other dimensions fixed, the core losses reduce due to the wider magnetic path, whereas the winding losses increase. Additionally, a higher maximum torque is reached due to reduced saturation. Results are compared in the machine\u27s torque-speed operating area regarding machine-part and total losses, continuous torque and transient overload capability, as well as during 19 low, middle and high-speed drive cycles regarding energy losses and peak winding temperature. The largest slot showed the lowest winding losses and thus the highest thermally limited torque capability. In contrast, the energy losses with the largest slot were the highest in 13 of the drive cycles, and the lowest in 11 of them with the smallest slot due to its lower part load (i.e. core) losses. The smallest slot would also result in the lowest material cost since it has the least copper