Dissertations / Theses on the topic 'HYBRID ELECTRIC VEHICLES (HEV)'

Hybrid electric vehicles are considered to be an important part of the future vehicle industry, since they decrease fuel consumption without decreasing the performance compared to a conventional vehicle. They use two or more power sources to propel the vehicle, normally one combustion engine and one electric machine. These power sources can be arranged in different topologies and can cooporate in different ways. In this thesis, dynamic models of parallel and series hybrid powertrains are developed, and different strategies for how to control them are compared.An optimization algorithm for decreasing fuel consumption and utilize the battery storage capacity as much as possible is also developed, implemented and tested.

Nowadays, the energy warehouse structures of EVs have to now no longer acquire big quantities of strength however additionally percentage out rapid dissimilarities of the burden. The increase and implementation of Electric Vehicles (EV) and Hybrid Electric Vehicles (HEV) are these days obtaining a massive momentum particularly because of environmental and gasoline sources to deal with. An electric powered automobile model is simulated withinside the Mat lab wherein an electric powered automobile load on the idea of speed, acceleration, torque, strength at load is analyzed. Suitable factors of Indian power cycle incorporating like drag coefficient, coefficient of rolling resistance, etc. parameters are analyzed. A Mat lab Simulink of the Brushless DC motor, Inverter circuit, commutation switching circuit, Buck converter, PID controller, sensor circuit, and ultra-capacitance battery control version is evolved for the evaluation of an electric powered automobile. In an electric-powered automobile, the available electricity as a consequence of the battery might not be constantly enough to fulfill the weight ultimatum, especially at some stage in height ephemeral conditions. Hence, an ultra-capacitor financial institution is used as a further electricity garage detail in an electric-powered automobile, which could deliver electricity to satisfy the height strength ultimatum and may enhance the overall performance at some stage in short-lived conditions. The mixed use of battery and ultra-capacitor improves the performance of the system, the battery operates inside shielded limits, battery dwelling receives more desirable, brings down the battery size, and enlarging the automobile overall performance. The obstacles are decreased electricity density, low lifestyles cycle, immoderate cost, and limited using span. Ultra-capacitors are related to the battery because it has a double-layer electrochemical capacitor with an extended lifestyles cycle, successful to build up one thousand instances greater strength than a traditional capacitor, more advantageous electricity density, and green rate and law of discharge.

The requirements on fuel consumption and emissions for passenger cars are getting stricter every year. This has forced the vehicle industry to look for ways to improve the performance of the driveline. With the increasing focus on electrification, a common method is to combine an electrical driveline with a conventional driveline that uses a petrol or diesel engine, thus creating a hybrid electric vehicle. To fully be able to utilise the potential of the driveline in such a vehicle, an efficient energy management strategy is needed. This thesis describes the development of an efficient route-based energy management strategy. Three different optimisation strategies are combined, deterministic dynamic programming, equivalent consumption minimisation strategy and convex optimisation, together with segmentation of the input data. The developed strategy shows a decrease in computational time with up to more than one hundred times compared to a benchmark algorithm. When implemented in Volvo's simulation tool, VSim, substantial fuel savings of up to ten percent is shown compared to a charge-depleting charge-sustain strategy.

EPA testing methods for calculation of fuel economy label ratings, which were revised beginning in 2008, use equations that weight the contributions of fuel consumption results from multiple dynamometer tests to synthesize city and highway estimates that reflect average U.S. driving patterns. The equations incorporate effects with varying weightings into the final fuel consumption, which are explained in this thesis paper, including illustrations from testing. Some of the test results used in the computation come from individual phases within the certification driving cycles. This methodology causes additional complexities for hybrid electric vehicles, because although they are required to have charge-balanced batteries over the course of a full drive cycle, they may have net charge or discharge within the individual phases. The fundamentals of studying battery charge-balance are discussed in this paper, followed by a detailed investigation of the implications of per-phase charge correction that was undertaken through testing of a 2010 Toyota Prius at Argonne National Laboratoryâ s vehicle dynamometer test facility. Using the charge-correction curves obtained through testing shows that phase fuel economy can be significantly skewed by natural charge imbalance, although the end effect on the fuel economy label is not as large. Finally, the characteristics of the current 5-cycle fuel economy testing method are compared to previous methods through a vehicle simulation study which shows that the magnitude of impact from mass and aerodynamic parameters vary between labeling methods and vehicle types.
Master of Science

Optimal control of energy flows in a Hybrid Electric Vehicle (HEV) is crucial to maximising the benefits of hybridisation. The problem is complex because the optimal solution depends on future power demands, which are often unknown. Stochastic Dynamic Programming (SDP) is among the most advanced control optimisation algorithms proposed and incorporates a stochastic representation of the future. The potential of a fully developed SDP controller has not yet been demonstrated on a real vehicle; this work presents what is believed to be the most concerted and complete attempt to do so. In characterising typical driving patterns of the target vehicles this work included the development and trial of an eco-driving driver assistance system; this aims to reduce fuel consumption by encouraging reduced rates of acceleration and efficient use of the gears via visual and audible feedback. Field trials were undertaken using 15 light commercial vehicles over four weeks covering a total of 39,300 km. Average fuel savings of 7.6% and up to 12% were demonstrated. Data from the trials were used to assess the degree to which various legislative test cycles represent the vehicles’ real-world use and the LA92 cycle was found to be the closest statistical match. Various practical considerations in SDP controller development are addressed such as the choice of discount factor and how charge sustaining characteristics of the policy can be examined and adjusted. These contributions are collated into a method for robust implementation of the SDP algorithm. Most reported HEV controllers neglect the significant complications resulting from extensive use of the electrical powertrain at high power, such as increased heat generation and battery stress. In this work a novel cost function incorporates the square of battery C-rate as an indicator of electric powertrain stress, with the aim of lessening the affliction of real-world concerns such as temperatures and battery health. Controllers were tested in simulation and then implemented on a test vehicle; the challenges encountered in doing so are discussed. Testing was performed on a chassis dynamometer using the LA92 test cycle and the novel cost function was found to enable the SDP algorithm to reduce electrical powertrain stress by 13% without sacrificing any fuel savings, which is likely to be beneficial to battery health.

With the increasing adoption and usage of hybrid electric vehicle (HEV) technologies, there is a growing recognition that attributes such as dynamics, driveability and refinement can have an adverse affect on customer acceptance. There are a number of new challenges associated with their refinement, in particular their sound quality. These issues include: understanding customers’ perceptions of new sound sources, such as electric motor/generators (M/G) and electronic switching devices; reduced masking from the internal combustion engine (ICE); the effect that a more advanced control strategy can have on vehicle-level sound (both internally and externally); and the effect of new sound character on customer perception. Given these new challenges for the sound quality of HEVs, the best approach for learning about perceptions needed to be determined. Interactive noise, vibration and harshness (NVH) simulation is well suited to further our understanding of these issues. The process for developing models for interactive NVH simulation of conventional vehicles is well established. However, research was necessary to both enhance this process for the creation of HEV models and to create new assessment methods. This report gives a brief overview of a project to deliver this. The key stages were: classification of unique HEV operations; development of a HEV NVH model; validation of the NVH model to determine its suitability for interactive simulation; leading onto recommendations for the use of new HEV sound quality models for assessment. An interactive HEV model has been successfully created and used in a number of newly created HEV sound quality evaluations. Three assessments were created and carried out which addressed new HEV related refinement issues of varying ICE masking, varying control strategy and the effect of added interior synthesized sound on customer perception. Key findings included: preference for reduced internal combustion engine (ICE) sound in the Toyota Prius and significant differences in perception of the same HEV, over the same drive cycle with varying initial battery state-of-charge (SoC). The process developed and carried out and learning achieved has been documented as a selection of flowcharts and can be used by OEMs or sound specialists as a means for improving HEV sound quality.

The lithium ion battery is today mainly used in cell phonesand laptops. In the future, this kind of battery might beuseful in hybrid electric vehicles as well.

In this work, the main focus has been to gain more knowledgeabout the lithium ion battery in the hybrid electric vehicle(HEV) and more precisely to examine what processes of thebattery that are limiting at HEV currents. Both experiments andmathematical modelling have been used. In both cases, highrate, pulsed currents typical for the HEV, have been used.

Two manuscripts have been written. Both of them concern thebehaviour of the battery at HEV load, but from different pointsof view. The first one concerns the electrochemical behaviourof the battery at different ambient temperatures. Theexperimental results of this paper were used to validate amathematical model of a Li-ion battery. Possiblesimplifications of the model were identified. In this work itwas also concluded that the mass transfer of the electrolyte isthe main limiting process within the battery. The mass transferof the electrolyte was further studied in the second paper,where the concentration of lithium ions was measured indirectlyusing in situ Raman spectroscopy. This study showed that themathematical description of the mass transfer of theelectrolyte is not complete. One main reason of this issuggested to be the poor description of the physical parametersof the electrolyte. These ought to be further studied in orderto get a better fit between concentration gradients predictedby experiments and model respectively.

Hybrid electric vehicles have two power sources - an internal combustion engine and an electric motor. These vehicles are of great interest because they contribute to a decreasing fuel consumption and air pollution and still maintain the performance of a conventional car. Different topologies are described in this thesis and especially the series and parallel hybrid electric vehicle and Toyota Prius have been studied.

This thesis also depicts modelling of a reference car and a series hybrid electric vehicle in Modelica. When appropriate, models from the Modelica standard library have been used. Models for a manual gearbox, final drive, wheel, chassis, air drag and a driver have been developed for the reference car.

For the hybrid electric vehicle a continuously variable transmission, battery, an electric motor, fuel cut-off function for the internal combustion engine and a converter that distributes the current between generator, electric motor and internal combustion engine have been designed.

These models have been put together with models from the Modelica standard library to a reference car and a series hybrid electric vehicle which follows the NEDC driving cycle. A sketch for the parallel hybrid electric vehicle and Toyota Prius have also been made in Modelica.

Developed models have been introduced into the Modelica library VehProLib, which is a vehicle propulsion library under development by Vehicular Systems, Linköpings universitet.

System level parametric design of hybrid electric vehicles involves estimation of the power ratings as well as the values of certain parameters of the components, given the values of the performance parameters. The design is based on certain mathematical equations or ‘design rules’, which relate the component parameters and the performance parameters. The flow of the design algorithm is uni-directional and fixed, and cannot be altered. This thesis proposes a new method for such parametric design, called omni- directional design, which does not have a fixed sequence like the conventional design, but can start with any parameters of the designer’s choice. The designer is also able to specify the input parameters over a range, instead of a point (one, fixed value) input. Scenarios having a point input, but values of an output which can vary over a range for the point input, can also be studied.

In recent years, rules and regulations regarding fuel consumption of vehicles and the amount of emissions produced by them are becoming stricter. This has led the automotive industry to develop more advanced solutions to propel vehicles to meet the legal requirements. The Hybrid Electric Vehicle is one of the solutions that is becoming more popular in the automotive industry. It consists of an electrical driveline combined with a conventional powertrain, propelled by either a diesel or petrol engine. Two power sources create the possibility to choose when and how to use the power sources to propel the vehicle. The strategy that decides how this is done is referred to as an energy management strategy. Today most energy management strategies only try to reduce fuel consumption using models that describe the steady state behaviour of the engine. In other words, no reduction of emissions is achieved and all transient behaviour is considered negligible.  In this thesis, an energy management strategy incorporating engine dynamics to reduce fuel consumption and nitrogen oxide emissions have been designed. First, the models that describe how fuel consumption and nitrogen oxide emissions behave during transient engine operation are developed. Then, an energy management strategy is developed consisting of a model predictive controller that combines the equivalent consumption minimization strategy and convex optimization. Results indicate that by considering engine dynamics in the energy management strategy, both fuel consumption and nitrogen oxide emissions can be reduced. Furthermore, it is also shown that the major reduction in fuel consumption and nitrogen oxide emissions is achieved for short prediction horizons.

Georgia Tech has the privilege of competing in EcoCAR 3, a four-year competition in which 16 universities are given a stock 2016 Chevrolet Camaro and work to transform it into a hybrid electric sports car. In this thesis, an overview of the first two years of the author’s work on the team as the Engineering Manager, the graduate student overseeing all vehicle engineering work, will be detailed. The competition will be introduced and described before a discussion on vehicle electrification and the various ways it has been achieved by manufacturers and competition teams. Next, the design of the Georgia Tech vehicle will be presented with a focus on powertrain and supporting component selection. The vehicle model underlying many of these decisions will then be discussed in detail, showing how the team used Simulink and Engineering Equation Solver to effectively predict vehicle performance, emissions, energy consumption, and cooling needs. Building on this, the controls design process known as model/software/hardware in the loop will be discussed in the context of the Georgia Tech team’s use of this process. Finally, a progress update will be given, including photos of the team vehicle in current build state weeks before the Year 2 Competition.

This dissertation presents a study focused on exploring the integration of Dual-Clutch Transmissions (DCTs) in Hybrid Electric Vehicles (HEVs). Among the many aspects that could be investigated regarding the electrification of DCTs, research efforts are undertaken here to the development of control strategies for improving vehicle dynamic performance during gearshifts and the energy management of HEVs. In the first part of the dissertation, control algorithms for upshift and downshift maneuvers are developed for a Plug-in Hybrid Electric Vehicle (PHEV) architecture in which an electric machine is connected to the output of the transmission, thus obtaining torque filling capabilities during gearshifts. Promising results, in terms of the vehicle dynamic performance, are obtained for the two transmission systems analyzed: Hybrid Automated Manual Transmission (H-AMT) and Hybrid Dual-Clutch Transmission (H-DCT). On the other hand, the global optimal solution to the energy management problem for a PHEV equipped with a DCT is found by developing a detailed Dynamic Programing (DP) formulation. The main control objective is to reduce the fuel consumption during a driving mission. Based on the DP results, a novel real-time implementable Energy Management Strategy (EMS) is proposed. The performance of such controller, in terms of the overall fuel usage, is close to that of the optimal solution. Furthermore, the developed approach is shown to outperform a well-known causal strategy: Adaptive Equivalent Consumption Minimization Strategy (A-ECMS). One of the main aspects that differentiates the EMSs proposed here to those presented in previous works is the introduction of a model to estimate the energy consumption during gearshifts in DCTs. Thus, this dissertation illustrates how through the electrification of powertrains equipped with DCTs both the vehicle dynamic performance and the energy consumption can be improved.

This Master’s thesis deals with the issue of lead-acid batteries, which are used in hybrid electric vehicles. The lead-acid batteries works in mode PSoC. In this mode occurs to degradation mechanisms at negative electrodes. These degradation mechanisms reduce the battery life. The practical part of Master’s thesis describes the production and a compilation of experimental cells and experimental part examines the characteristics of lead-acid batteries with the pressure to the electrode system.

This master thesis project aims to complete and verify core functions of a test rig that is designed and built to emulate drive cycles for measuring the energy consumption of HEVs, especially a vehicle named ELBA from KTH Integrated Transport Research Lab (ITRL). To fulfill this goal, a simplified model is created for the test rig, whose involved parameters are identified through various experiments. Then the model is verified by both step voltage responses and sinusoidal current responses. Meanwhile, vehicle dynamics is modeled to calculate required resistance force for road slope emulation. Moreover, an existing method, vehicle equivalent mass, is utilized to compensate dynamic force of the vehicle body, enabling simulation of regenerative braking without an extra flywheel. Together with test rig’s model that is responsible for converting required resistance force to demanded current reference, the rig’s functions are completed and ready for final verification. As a result, the driver of the DC motor on the rig is found to has lower current limitation than required so that the rig is not able to entirely compensate dynamic force of the car. However, the feasibility of the principle is still proved by the tests. Based on the result, recommendations are given to solve the problem and achieve other improvements in the future.
Detta examensarbete syftar till att slutföra och verifiera kärnfunktioner i en testrigg som är designad och byggd för att emulera körcykler för att mäta energiförbrukningen för elhybridbilar, särskilt ett fordon som heter ELBA från KTH Integrated Transport Research Lab (ITRL). För att uppfylla detta mål skapades en förenklad modell för testriggen, vars parametrar identifieras genom olika experiment. Sedan verifieras modellen av både stegspänningssvar och sinusformade strömsvar. Under tiden modelleras fordonsdynamiken för att beräkna erforderlig motståndskraft för väglöpemulering. Samtidigt modelleras fordonsdynamiken för att beräkna den erforderliga motståndskraften för emulering av väglutningar. Dessutom används en befintlig metod, fordonsekvivalentmassa, för att kompensera fordonskroppens dynamiska kraft, vilket möjliggör simulering av regenerativ bromsning utan extra svänghjul. Tillsammans med testriggens modell som är ansvarig för att konvertera erforderlig motståndskraft till efterfrågad strömreferens, är riggens funktioner färdig och redo för slutlig verifiering. Som ett resultat har föraren av likström motorn på riggen visat sig ha lägre strömbegränsning än vad som krävs så att riggen inte helt kan kompensera bilens dynamiska kraft. Emellertid bevisas principens genomförbarhet fortfarande av testerna. Baserat på resultatet ges rekommendationer för att lösa problemet och uppnå andra förbättringar i framtiden.

The lead-acid batteries are most commonly used electrochemical power source. The lead-acid battery is the oldest type of secondary battery cells. This lead-acid batteries have a great use in hybrid electric vehicles (HEVs), which operate in different modes of vehicle operation. This is related to changes in battery temperature, caused by Joule heat taking place during discharging and chargingg the battery in a vehicle operation. The lead-acid batteries in hybrid electric vehicles work in mode PSoC.

The goal of the thesis is to study literature and to become familiar with problems of accumulators operating in the mode of hybrid electric vehicles (HEV). To work up problems of a potential impact of the influence on the system of the lead accumulator. Assemble the experimental cells with discontinuous system of parallel fins and to treat them with different operating modes. Then to evaluate the results.

Lead-acid batteries are most used secondary electrochemical power sources. Their basic principle has remained the same for several years; only the operating parameters are in development. Lead-acid batteries are used in hybrid electric vehicles (HEV), which operates in the partial charge PSoC. Sulphation is one of the possible failures lead-acid batteries in the HEV, especially the negative electrode. By adding additives to the negative active mass can reduce the rate of sulphation and increase ability to accept an electrical charge by negative electrode.

In recent years, the increasing cost of oil and Earth global warming due to greenhouse gases have pushed the scientific research, the governments and thus the markets in the direction of a higher efficiency of the systems in order to reduce the use of this fuel and therefore its associated emissions of CO2. Nowadays, the most involved sectors of this technological revolution are the fields of electricity generation and the transportation. In fact, these two sectors are the main accountable of CO2 global emission, that are associated for about 45% to electricity generation and for about 30% to transport. Moreover, it should be noted that although the oil is not a renewable energy source, currently about 40% of the production world energy depends on oil and the level of dependence rises to about 80% in the transportation sector where the majority of vehicles is powered by an engine fueled by oil derivatives. For these reasons, the scientific research in the last decade was focusing on these issues in particular in emerging fields such as distributed cogeneration and hybrid electric vehicles. In particular, new systems of distributed energy are studied, which are capable to increase the energy efficiency of the plant because the electrical and thermal energy are produced in combined way and directly in the site where they are required. In this way the losses of the network can be reduced. Instead, in the field of hybrid electric vehicles the use of the electric machine can help to increase the efficiency of the power-train in the various working points. These hybrid systems allow to reduce up to 30% the fuel consumption and associated emissions compared to a conventional vehicle. With this historical context this thesis is focused in the study of a power-train structure of domestic cogeneration system or a vehicle, namely the analysis of a system composed by an internal combustion engine directly connected to an electric machine. The two principal tasks of the electric machine are: startup of the internal combustion engine and generate on electric energy. In the case of a hybrid electric vehicle, in addition to those listed above, there are other two operation modes that are: increase the engine torque during the acceleration and recovering the energy during braking phase. Among the various types of electrical machines existing in the market, the permanent magnet synchronous machines take up an important position in the cogeneration and hybrid vehicle fields. In fact, this kind of electric machine allows to obtain: a high performance, high torque density, high overload capacity, a good robust construction, compact volume, and therefore low weight. Furthermore this type of electric machine can work at variable speeds and operate as motor and as generator with comparable performance. For this reason in this Ph.D. thesis the electrical drives composed by an internal combustion engines direct connected to permanent magnet synchronous electric machines will be presented. The author’s doctoral thesis has been carried out at the Electric Drive Laboratory of University of Padova, which since more than twenty years is active in the design of electrical machines and their control through research projects with industrial partners and scientific publications in journals and in international conferences. Therefore, although in the literature there are several books discussing an electric drives, thanks to the experience acquired in this laboratory the author intention is to emphasize with greater detail the aspects and basic notions which in his opinion are fundamental to the design of on electric drive devoted to the applications subject of this work. In addition, in the opinion of the author, unlike a paper on journal or conference the doctoral thesis should be reasonably self-contained and should be understandable even by a non expert of this field of research; therefore also basic aspects of an electric drive and its control have been reported with detail. So the work reported in this thesis is essentially composed by two parts, the first part is made up by the first four Chapters and the second one is composed by the last two Chapters. In the first part of Ph.D. thesis the basic aspects, that are required for a good knowledge on the electric drives field, have been reported. In particular the design aspects and fundamental characteristics of electric machine control, operating limits of a permanent magnet synchronous machine, and power converter have been pointed out. The second part of Ph.D. thesis is focused on the design aspects of electric drive for a domestic cogeneration system and for hybrid electric motorcycle. In particular for CHP system some effective techniques, that can help to reduce the vibration and noise problems due to the internal combustion engine, have been described. In the field of hybrid electric motorcycle the main design choices carried out in order to achieve a hybrid electric motorcycle prototype with good performance are reported.
In questi ultimi anni l’aumento del costo del petrolio e il riscaldamento globale della terra dovuto ai gas serra ha spinto il settore scientifico, i governi e quindi il mercato nella direzione di una più alta efficienza dei sistemi con lo scopo di ridurre l’utilizzo di questo combustibile e quindi le sue emissioni di CO2 associate. Oggigiorno i settori più coinvolti in questa rivoluzione tecnologica sono il settori della generazione di energia elettrica e il settore dei trasporti. Infatti questi due settori sono i principali responsabili di emissioni di CO2 globali della terra che sono associate per circa il 45% alla generazione elettrica e per circa 30% ai trasporti. Inoltre va ricordato che sebbene il petrolio non sia una fonte di energia rinnovabile attualmente circa il 40% dell’energia mondiale dipende dal petrolio e questo livello di dipendenza sale a circa 80% nel settore dei trasporti dove la maggior parte dei veicoli è spinta da un motore alimentato da derivati del petrolio. Per questi motivi la ricerca scientifica negli ultimi dieci anni si sta concentrando su questi problematiche in particolare nei settori emergenti quali cogenerazione distribuita e veicoli ibridi. In particolare vengono studiati nuovi impianti di energia distribuita capaci di aumentare l’efficienza energetica producendo in maniera combinata energia elettrica e termica direttamente dove richiesta e solo se necessaria in questo modo si riducendo le perdite di rete. Nel settore dei veicoli ibridi invece l’utilizzo del motore elettrico può aiutare ad aumentare l’efficienza del motore termico nei vari punti di lavoro, questi sistemi consentono infatti di migliorare fino al 30% le prestazioni in termini di consumi ed emissioni rispetto ad un veicolo tradizionale. Con questo contesto storico la tesi si è focalizzata nello studio di una struttura della catena di potenza di un veicolo o di un sistema di cogenerazione di piccola taglia ossia l’analisi di un sistema composto da un motore endotermico direttamente calettato con una macchina elettrica. La macchina elettrica viene generalmente utilizzata con due funzioni principali: avviare il motore a combustione e generare energia elettrica. Nel caso di un veicolo ibrido vi sono altre due funzioni che si aggiungono a quelle appena elencate ossia la fase di incremento di coppia durante le accelerazioni e una fase di recupera di energia durante le frenate. Tra le varie tipologie di macchine elettriche esistenti nel mercato, le macchine sincrone a magnete permanente occupano un posto di rilievo in questi settori. Infatti questa tipologia di macchina elettrica consente di ottenere: un alto rendimento, un’alta densità di coppia, notevole capacità di sovraccarico, una buona robustezza costruttiva, volumi compatti e quindi peso ridotto. Inoltre questo tipo di macchina può lavorare a velocità variabile e può operare con prestazioni aragonabili sia come motore che come generatore. Per questo motivo nella tesi verranno presentati azionamenti elettrici basati su motori a combustione interna calettati a macchine elettriche sincrone a magneti permanenti. La tesi di dottorato dell’autore è stata svolta presso il laboratorio di azionamenti elettrici di Padova, il quale da più di venti anni è attivo nel campo della progettazione di macchine elettriche e del loro controllo mediante progetti di ricerca con partner industriali e pubblicazioni scientifiche su riviste e su conferenze internazionali. Quindi sebbene siano presenti in letteratura molti libri che parlano di azionamenti elettrici grazie all’esperienza dell’autore maturata in questo laboratorio l’autore ha voluto enfatizzare con maggiore dettaglio gli aspetti e le nozioni che secondo la sua opinione sono fondamentali per la progettazione di un azionamento elettrico. Inoltre secondo il parere dell’autore al tesi di dottorato a differenza di un articolo su conferenza o su rivista deve essere autonoma e deve poter essere compresa anche da un non esperto del settore pertanto sono stati riportati con dettaglio anche aspetti base di una azionamento elettrico e del controllo motore. Quindi il lavoro riportato in questa tesi di dottorato è diviso sostanzialmente in due parti la prima composta dai primi quattro capitoli e la seconda parte composta dagli ultimi due capitoli. Nella prima parte sono state riportate le nozioni fondamentali necessarie per una buona conoscenza sul settore degli azionamenti elettrici in particolare nella parte di controllo motore, limiti di funzionamento di un motore sincrono a magneti permanenti e inverter di potenza. Mentre la seconda parte si è focalizzata sulla descrizione della progettazione di un azionamento per un sistema di cogenerazione domestica e per motociclette ibride. Nell’ambito della cogenerazione sono state descritte alcune tecniche che consentono di ridurre il problema delle vibrazioni dovute al motore a combustione interna. Nel settore della motocicletta ibrida sono state mostrate le principali scelte di progettazione effettuate per realizzare un prototipo efficace e funzionante di motocicletta ibrida.

This Master’s thesis deals with the lead-acid batteries, which are alternativ power supply. The lead-acid batteries are the oldest type of battery cells. This lead-acid batteries have a great use in hybrid electric vehicles (HEVs), which operate in different modes of vehicle operation. These modes correspond to the reactions taking place during discharging and charging the battery. The lead-acid batteries in hybrid electric vehicles work in mode PSoC. The practical part of the Master`s thesis examines how the characteristics of lead-acid batteries are modified due to admixture of glass fibers into negative active material and application of pressure to the electrode system.

To develop more competitive solutions, one of the trends in the development of drive systems for electric and hybrid electric vehicles (EVs/HEVs) is to integrate the power electronic converter and the electric motor. This thesis aims to investigate the performance and the operation of modular converters in integrated motor drive systems for EVs/HEVs. In the first part, the concept of integrated modular motor drive systems for EVs/HEVs is introduced. Three suitable modular converter topologies, namely, the stacked polyphase bridges (SPB) converter, the parallel-connected polyphase bridges (PPB) converter and the modular high frequency (MHF) converter, are evaluated and compared with conventional electric drives in terms of power losses, energy storage requirements, and semiconductor costs. In the second part of the thesis, the harmonic content of the dc-link current of the SPB converter is analyzed. By adopting an interleaving modulation the size of the dc-link capacitor can be reduced without increasing the switching frequency, which is beneficial for achieving a compact integrated system. This method allows for around 80% reduction of the dc-link capacitance for vehicle drives, resulting in a significant size reduction of the power converter and improved integration. Finally, a communication-based distributed control system for the SPB converter is presented. The communication delay arising from the serial communication is inevitable, thus a timing analysis is also presented. It has been found that stability is maintained even when the baud rate of the SPI communication is lower than 1 Mbps, indicating that other communication protocols with lower bandwidths can also be adopted for this topology. The analytical investigations provided in this thesis are validated by experiments on a four-submodule laboratory prototype. Experimental results verify the correctness of the theoretical analysis, as well as the dynamic performance of the distributed control system.

QC 20161121

Thesis (M.S.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains xvi, 112 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 85-87).

The automotive industry is required to deal with increasingly stringent legislationfor greenhouse gases. Hybrid Electric Vehicles, HEV, are gaining acceptance as thefuture path of lower emissions and fuel consumption. The increased complexityof multiple prime movers demand more advanced control systems, where futuredriving conditions also becomes interesting. For a plug-in Hybrid Electric Vehicle,PIHEV, it is important to utilize the comparatively inexpensive electric energybefore the driving cycle is complete, this for minimize the cost of the driving cycle,since the battery in a PIHEV can be charged from the grid. A strategy with lengthinformation of the driving cycle from a global positioning system, GPS, couldreduce the cost of driving. This by starting to blend the electric energy with fuelearlier, a strategy called blended driving accomplish this by distribute the electricenergy, that is charged externally, with fuel over the driving cycle, and also ensurethat the battery’s minimum level reaches before the driving cycle is finished. Astrategy called Charge Depleting Charge Sustaining, CDCS, does not need lengthinformation. This strategy first depletes the battery to a minimum State of Charge,SOC, and after this engages the engine to maintain the SOC at this level. In thisthesis, a variable SOC reference is developed, which is dependent on knowledgeabout the cycle’s length and the current length the vehicle has driven in the cycle.With assistance of a variable SOC reference, is a blended strategy realized. Thisis used to minimize the cost of a driving cycle. A comparison between the blendedstrategy and the CDCS strategy was done, where the CDCS strategy uses a fixedSOC reference. During simulation is the usage of fuel minimized; and the blendedstrategy decreases the cost of the driving missions compared to the CDCS strategy.To solve the energy management problem is a model predictive control used. Thedesigned control system follows the driving cycles, is charge sustaining and solvesthe energy management problem during simulation. The system also handlesmoderate model errors.
Fordonsindustrin måste hantera allt strängare lagkrav mot utsläpp av emissioneroch växthusgaser. Hybridfordon har börjat betraktas som den framtida vägenför att ytterligare minska utsläpp och användning av fossila bränslen. Den ökadekomplexiteten från flera olika motorer kräver mera avancerade styrsystem. Begränsningarfrån motorernas energikällor gör att framtida förhållanden är viktigaatt estimera. För plug-in hybridfordon, PIHEV, är det viktigt att använda denvvijämförelsevis billiga elektriska energin innan fordonet har nått fram till slutdestinationen.Batteriets nuvarande energimängd mäts i dess State of Charge, SOC.Genom att utnyttja information om hur långt det är till slutdestinationen från ettGlobal Positioning System, GPS, blandar styrsystemet den elektriska energin medbränsle från början, detta kallas för blandad körning. En strategi som inte hartillgång till hur långt fordonet ska köras kallas Charge Depleting Charge Sustaining,CDCS. Denna strategi använder först energin från batteriet, för att sedanbörja använda förbränningsmotorn när SOC:s miniminivå har nåtts. Strategin attanvända GPS informationen är jämförd med en strategi som inte har tillgång tillinformation om körcykelns längd. Blandad körning använder en variabel SOC referens,till skillnad från CDCS strategin som använder sig av en konstant referenspå SOC:s miniminivå. Den variabla SOC referensen beror på hur långt fordonethar kört av den totala körsträckan, med hjälp av denna realiseras en blandad körning.Från simuleringarna visade det sig att blandad körning gav minskad kostnadför de simulerade körcyklerna jämfört med en CDCS strategi. En modellbaseradprediktionsreglering används för att lösa energifördelningsproblemet. Styrsystemetföljer körcykler och löser energifördelningsproblemet för de olika drivkällorna undersimuleringarna. Styrsystemet hanterar även måttliga modellfel.

This thesis deals with the energy management problem of series hybrid electric vehicles (HEVs), where the objective is to maximize fuel economy for general driving. The work employs a high-fidelity model that has been refined to deliver appropriate level of dynamics (for the purposes of this research) at an acceptable computational burden. The model is then used to design, test and study established conventional control strategies, which then act as benchmarks and inspiration for proposed novel control strategies. A family of efficiency maximizing map strategies (EMMS) are developed based on a thorough and holistic analysis of the powertrain efficiencies. The real-time variants are found to deliver impressive fuel economy, and the global variant is found to outperform the conventional global benchmark. Two heuristic strategies are developed (exclusive operation strategy (XOS) and optimal primary source strategy (OPSS)) that are found to deliver significantly better fuel economy results, compared to conventional alternatives, and further desirable traits. This is found to be particularly related to the better use of modern start stop systems (SSSs) that has not been considered sufficiently in the past. A global heuristic strategy (GHS) is presented that successfully outperforms the conventional global benchmark without any particularly complex analysis. This exposes some of the limitations of optimization-based techniques that have been developed for simple vehicle models. Lastly, the sensitivity of the performance of the control strategies has been studied for variations in tuning accuracy, SSS efficiency, vehicle initial conditions, and general driving conditions. This allows a deeper insight into each control strategy, exposing strengths and limitations that have not been apparent from past work.

The main goal of this thesis study is the optimization of the basic design parameters of hybrid electric vehicle drivetrain components to minimize fuel consumption and emission objectives, together with constraints derived from performance requirements. In order to generate a user friendly and flexible platform to model, select drivetrain components, simulate performance, and optimize parameters of series and parallel hybrid electric vehicles, a MATLAB based graphical user interface is designed. A basic sizing procedure for the internal combustion engine, electric motor, and battery is developed. Pre-defined control strategies are implemented for both types of hybrid configurations. To achieve better fuel consumption and emission values, while satisfying nonlinear performance constraints, multi-objective gradient based optimization procedure is carried out with user defined upper and lower bounds of optimization parameters. The optimization process is applied to a number of case studies and the results are evaluated by comparison with similar cases found in literature.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
Nesta dissertação apresenta-se a avaliação da eficiência energética do Veículo Elétrico Híbrido em Série mediante o desenvolvimento teórico de dois protótipos de sistemas de propulsão elétrica e o estudo experimental do consumo de combustível do veículo original. A análise experimental foi feita mediante o desenvolvimento de uma bancada de teste, composta principalmente por um dinamômetro de chassis, um piloto automático e um medidor de vazão de combustível, acompanhado de toda a eletrônica que fez possível a aquisição de dados em cada teste. Neste estudo desenvolvem- se dois modelos teóricos de arquitetura para o sistema de propulsão do VEH, o primeiro composto de quatro motores, cada um embutido nas rodas do veículo, e o segundo composto por dois motores, cada um embutido nas rodas do eixo traseiro do veículo. Existem diversos procedimentos para poder embutir um motor na roda do veículo, o que se deve ter em conta é o peso, a potência e a eficiência na transmissão de potência. No desenvolvimento teórico do sistema de propulsão em cada roda, faz-se necessário o uso do redutor cicloidal, o qual permite uma redução de 3:1 até 119:1 em um só estágio com uma eficiência de transmissão de 93 por cento, conjuntamente com um motor de corrente contínua sem escovas, o qual tem uma alta densidade de potência. Os resultados da avaliação do sistema de propulsão elétrica dos protótipos mostram que o modelo de quatro motores nas rodas é mais eficiente em comparação com o modelo de dois motores embutidos nas rodas. Isto se deve ao fato do segundo modelo ser mais pesado, já que precisa uma maior quantidade de baterias e além disso de motores mais robustos. Na avaliação do consumo energético do VEH em comparação com o modelo original a gasolina, obtiveram-se resultados interessantes referentes à economia na utilização do recurso energético. O VEH teve um comportamento melhor em ciclos urbanos que em ciclos de estrada e a economia do recurso energético alcança 57,6 por cento quando se testa com ciclos urbanos e 11,4 por cento em ciclos de estrada.
This dissertation presents the evaluation of the energy efficiency of a series hybrid electric vehicle through the theoretical development of two electric propulsion systems and an experimental study of fuel consumption of the original vehicle. The experimental analysis was done by a test setting, consisting mainly by a chassis dynamometer, an autopilot system and a fuel flowmeter, all connected to the data acquisition system. In this study it was developed two theoretical models of propulsion systems for HEV. The first one consists of four in-wheel motors and the second one consists of two in-wheel motors on the rear axle. There are various methods for embedding a motor in the wheel. It is necessary to consider the weight, power and transmission efficiency. In the theoretical model it was considered a cycloidal reducer, which allows a reduction of 3:1 to 119:1 in one stage with an efficiency of 93 percent, together with a brushless DC motor, which has a high power density. The results of the evaluation of the electric propulsion systems show that the model with four in-wheel motors is more efficient than the model with two in-wheel motors. This is a consequence of the fact that the second model is heavier, because it needs a bigger amount of batteries and more robust motors. In the evaluation of the HEV energy consumption in comparison with the original gasoline model, it was observed interesting results regarding the energy savings. The HEV presents better performance in urban cycles that in road cycles, saving 57,6 per cent of the consumed energy in urban cycles and 11,4 per cent in road cycles.

In this research study, the feasibility of using one of the Hybrid Permanent Magnet (HPM) machine topologies acting as a generator with a passive rectification stage is considered. The primary application area is in the power-train of a series hybrid electric vehicle where the concept will be considered as an alternative to brushless PM machines interfacing to the vehicle power-train via active power electronic converters. The electro-magnetic design of the two main parts in the selected HPM generator topology and their individual system behaviour at normal and rated conditions will be studied. Prediction of the transient and steady state temperature in some of the HPM machine parts will be conducted based on commercial thermal analysis software. Two HPM machine stator winding configurations; 3-phase and 9-phase, with their relevant passive rectification stages will be analysed in terms of their terminal and DC-link output power along with the quality of the generated DC output voltage. An investigation of the operational characteristic of the HPM generator when delivering a fixed power at a fixed speed into a dynamic DC voltage source typical of a hybrid electric vehicle power-train subject to urban driving regimes will be presented. The research work will be a mixture of simulation studies using electro-magnetic finite element analysis (FEA), transient machine and system analysis via SimPower, a Matlab/Simulink toolbox set, along with test validation via a representative prototype HPM generator configuration and its interface to an experimental electrical system evaluation platform.

Inclusion of real physics based dynamics instead of conventional charts and maps, while capturing the transient behavior of the overall powertrain is the primary objective of this research effort. The multi-body model of the longitudinal car is described in detail, including mathematical models of tyres, suspensions, aerodynamic behaviour and continuous variable transmission (CVT). The PMSM and PMSG along with DC/AC, AC/DC are modeled in the d - q frame. A novel frictional torque function, predicting all mechanical and electrical losses except resistance loss, is proposed. The results of the proposed frictional torque function compare well with the results obtained from empirical sources. Average models for AC/DC, DC/AC and DC/DC converters are used to ensure the simplicity and feasibility of the simulation in acceptable time scale. Bidirectional converters fed-back the recaptured mechanical energy during regeneration to the battery. A switching-frequency dependent average model for soft-switching isolated DC/DC converter is used in this research. A generic dynamic Li-ion battery model has been chosen which expresses the electrochemical parameters of the battery directly in terms of electrical parameters of the circuit. A control oriented, fast and simple 0D model of the turbocharged diesel engine, combining mean value model and filling and emptying models has been presented in this work. Inlet manifold and exhaust manifolds are modeled as filling and emptying model, engine cylinder dynamics with mean value model, engine torque as a three dimensional map of indicated torque (Teng = f (ωeng,λ)), engine speed ωeng and air-fuel ratio λ, and flow characteristics of the compressor and turbine are modelled with mean value model. A novel control mechanism is proposed to control the fuel mass flow rate and relative air-fuel ratio. Simulation results of the present engine model are validated against a high-fidelity commercial Ricardo-wave model of the same engine. A novel DC-link control mechanism is proposed to simulate the transient operation of the series HEV powertrain during different modes of operation. The supervisory control is implemented to meet the driver’s demand for the traction power, at the same time avoiding over-discharging of the battery below certain threshold level, and optimizing the drive train efficiency, fuel consumption and emissions. On the basis of thermostat control and power follower, a novel “load follower” supervisory control strategy is proposed in the present work. A PI controller based driver model is developed and performance seems satisfactory while tracking the standard NEDC cycle. Simulation results are validated by energy balance computations and available transient and steady state data points for individual components as well as the overall powertrain. The research has successfully achieved the goal of developing a complete model for a series hybrid powertrain while capturing the transient performance of the all the components involved in the powertrain with module based, control oriented and forward facing modelling approach.

Interest in hybrid electric vehicles (HEVs) and electric vehicles (EVs) has increased rapidly over recent years from both industrial and academic viewpoints due to increasing concerns about environmental pollution and global oil usage. In the automotive sector, huge efforts have been invested in vehicle technology to improve efficiency and reduce carbon emissions with, for example, hybrid and electric vehicles. This thesis focuses on one design area of these vehicles – the transmission – with the aim of investigating the potential benefits of improved transmissions for HEVs and EVs. For HEVs, a novel transmission developed by Nexxtdrive based on a twin epicyclic design is analysed using a matrix method and its performance is compared with the more common single epicyclic arrangement used successfully in the Toyota Prius. Simulation models are then used to compare the performance of a typical HEV passenger car fitted with these two transmissions over standard driving cycles. The conclusion is that the twin epicyclic offers substantial improvements of up to 20% reduction in energy consumption, though the benefits are sensitive to the driving cycle used. For EVs, most designs to date have used a single fixed ratio transmission, and surprisingly little research has explored whether multi-geared transmissions offer any benefits. The research challenge is whether it is possible to optimise the usage of the electric motor in its region of high efficiency by controlling the transmission. Simulation results of two EV examples confirm that energy consumption benefits are indeed achievable – of between 7 and 14% depending on the driving cycle. Overall, the original aspects of this work – the analysis and modelling the twin epicyclic gearbox; the analysis and modelling the twin epicyclic system in a vehicle and a comparison of the results with single epicyclic system; and the analysis and modelling of EVs with and without a transmission system of varying levels of complexity – have shown that there are worthwhile performance benefits from using improved transmission designs for low carbon vehicles.

Une des voies d’amélioration des véhicules hybrides et électriques est l’utilisation de moteurs tournant plus vite, jusqu’à plus de 42.000tr/min. Le but est d’augmenter la densité de puissance et le rendement des groupes motopropulseurs. Pour utiliser ces moteurs de nouveaux réducteurs mécaniques doivent être développés. Cela doit se faire sans générer de surcoût important face aux solutions utilisées à basse vitesse et en assurant un niveau de performance énergétique élevé. Cette thèse se situe en amont de la phase de conception d’un réducteur haute vitesse lubrifié par barbotage. Elle a pour but d’identifier les problèmes d’échauffement et de pertes de puissance ainsi que de proposer des pistes d’amélioration énergétique. Ce travaille propose la modélisation thermomécanique de l’étage grande vitesse (GV) du réducteur, réalisée à l’aide de la méthode des réseaux thermiques. Ce modèle couple les pertes de puissance avec les températures. Une attention particulière est portée sur la modélisation des roulements de l’arbre GV. Un nouveau modèle thermomécanique de roulement est développé. Les pertes par barbotage deviennent importantes à grande vitesse. Une méthode permettant de fortement les réduire est caractérisée
A way to improve both electric and hybrid vehicles is to use high speed motors, operating over than 42.000rpm. The goal is to increase the power density and the efficiency of powertrains. Using these new motors, new gearboxes should be developed. This must be done without generating significant additional cost regarding already mastered low speed solutions. High energy performance level also has to be maintained. This PhD comes before the design phase of a high-speed oil bath lubricated gearbox. It aims to identify the warm-up and power loss problems, and propose ways to improve efficiency. This work proposes a thermomechanical modelling of the gearbox’s first stage, using the thermal network method. This model links power losses with temperatures. Particular attention is paid to high speed bearing modelling. A new thermomechanical model of rolling element bearing is developed. As churning losses being significant at high speeds, a method to greatly reduce this power loss is characterized

Thesis (M.S.)--West Virginia University, 2000.
Title from document title page. Document formatted into pages; contains xii, 112 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 111-112).

Thesis (M.S.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains xiii, 93 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 90-93).

Thesis (M.S.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains viii, 109 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 71-72).

This thesis focuses on the feasibility of designing a commercial hybrid electric vehicle (HEV). In this work, relevant system models are developed for the vehicle including powertrain, braking system, electrical machines and battery. Based on these models ten different HEV configurations are assembled for detailed assessment of fuel consumption. This thesis also proposes a smart power management strategy which could be applied to any kind of HEV configuration. The suggested expert system deals with the external information about the driving conditions and modes of the driver as well as the internal states of the internal combustion engine efficiency and the state of charge of the battery, and decides on the power distribution between two different power supplies based on the predefined algorithms. The study illustrates the characteristics of the powertrain components for various HEV configurations. The work also shows the power flow of HEV configurations with the developed smart power management system and therefore, the effectiveness of power management strategies has been evaluated in detail.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.
Includes bibliographical references (p. 63-65).
Hybrid Electric Vehicles (HEVs) with path-forecasting belong to the class of fuel efficient vehicles, which use external sensory information and powertrains with multiple operating modes in order to increase fuel economy. Their main characteristic is that the decision to charge and discharge the battery is made in part by using a prediction of future road conditions. The increasing presence of GPS navigational systems in the standard feature sets of the modern vehicles suggests that path predictive methods applied to HEVs constitute one of the most promising directions towards the solution of serious problems of our era, such as the energy problem, the increasing cost of oil, and the greenhouse gas emissions. In the current project we are given a route and an HEV simulation model, and we aim to minimize the fuel consumption of the vehicle along the route. Towards this direction, we adopt a novel way of decomposing the route into a series of route segments connected to each other and linking the origin to the destination. For each route segment, the road grade, the segment length, and the nominal speed are available. Then, the main idea of our method is to prescribe those set-points of the state of charge of the battery for each road segment, that result in the most fuel efficient travel between the origin and the destination.
by Georgia-Evangelina Katsargyri.
S.M.