Optimal design and implementation of a drivetrain for an ultra-light electric vehicle

This paper presents an integrated design of a drivetrain for a single-person ultra-light electric vehicle (ULEV). To calculate losses and efficiency of the inverter, the permanent magnet synchronous machines (PMSMs) and the gearbox, parameterised analytical models are used. For the gearbox - which has a single gear ratio - the studied parameters are the gear ratio, the number of stages, the number of teeth and the module of each spur gear combination. The novelty of the paper is that it learns how the total average efficiency and the total mass of the drivetrain depend on the gear ratio, on the number of stages in the gearbox, on the motor parameters and on the chosen several driving cycles including the new European driving cycle (NEDC). On the basis of the presented results, it is possible to choose the right configuration of power electronics, PMSM and gearbox in order to have a good trade-off between high efficiency and low mass

Design, Modelling and Verification of Distributed Electric Drivetrain

The electric drivetrain in a battery electric vehicle (BEVs) consists of an electric machine, an inverter, and a transmission. The drivetrain topology of available BEVs, e.g., Nissan Leaf, is centralized with a single electric drivetrain used to propel the vehicle. However, the drivetrain components can be integrated mechanically, resulting in a more compact solution. Furthermore, multiple drivetrain units can propel the vehicle resulting in a distributed drive architecture, e.g., Tesla Model S. Such drivetrains provide an additional degree of control and topology optimization leading to cheaper and more efficient solutions. To reduce the cost, the drivetrain unit in a distributed drivetrain can be standardized. However, to standardize the drivetrain, the drivetrain needs to be dimensioned such that the performance of a range of different vehicles can be satisfied. This work investigates a method for dimensioning the torque and power of an electric drivetrain that could be standardized across different passenger and light-duty vehicles. A system modeling approach is used to verify the proposed method using drive cycle simulations. The laboratory verification of such drivetrain components using a conventional dyno test bench can be expensive. Therefore, alternative methods such as power-hardware-in-the-loop (PHIL) and mechanical-hardware-in-the-loop (MHIL) are investigated. The PHIL test method for verifying inverters can be inexpensive as it eliminates the need for rotating electric machines. In this method, the inverter is tested using a machine emulator consisting of a voltage source converter and a coupling network, e.g., inductors and transformer. The emulator is controlled so that currents and voltages at the terminals resemble a machine connected to a mechanical load. In this work, a 60-kW machine emulator is designed and experimentally verified. In the MHIL method, the real-time simulation of the system is combined with a dyno test bench. One drivetrain is implemented in the dyno test bench, while the remaining are simulated using a real-time simulator to utilize this method for distributed drivetrain systems. Including the remaining drivetrains in the real-time simulation eliminates the need for a full-scale dyno test bench, providing a less expensive method for laboratory verification. An MHIL test bench for verification of distributed drivetrain control and components is also designed and experimentally verified

Next generation electric drives for HEV/EV propulsion systems: Technology, trends and challenges

In recent decades, several factors such as environmental protection, fossil fuel scarcity, climate change and pollution have driven the research and development of a more clean and sustainable transport. In this context, several agencies and associations, such as the European Union H2020, the United States Council for Automotive Research (USCAR) and the United Nations Economic and Social Commission for Asia (UN ESCAP) have defined a set of quantitative and qualitative goals in terms of efficiency, reliability, power losses, power density and economical costs to be met by next generation hybrid and full electric vehicle (HEV/EV) drive systems. As a consequence, the automotive electric drives (which consists of the electric machine, power converter and their cooling systems) of future vehicles have to overcome a number of technological challenges in order to comply with the aforementioned technical objectives. In this context, this paper presents, for each component of the electric drive, a comprehensive review of the state of the art, current technologies, future trends and enabling technologies that will make possible next generation HEV/EVs.This work has been partially supported by the Department of Education, Linguistic Policy and Culture of the Basque Government within the fund for research groups of the Basque university system IT978-16, by the Ministerio de Economía y Competitividad of Spain within the project DPI2014-53685-C2-2-R and FEDER funds and by the Government of the Basque Country within the research program ELKARTEK as the project KT4TRANS (KK-2015/00047 and KK-2016/00061), as well as by the program to support the specialization of Ph.D researchers at UPV/EHU ESPDOC16/25

Energy management of hybrid and battery electric vehicles

This work focuses on improving the fuel economy of parallel Hybrid Electric Vehicles (HEVs) and dual-motor Electric Vehicles (EVs) through energy management strategies. Both vehicle models have two propulsion branches, each powering a separate axle: An engine and an electric motor in the HEV and two electric motors in the EV. This similarity in the vehicle models emphasises the need for similar energy management solutions. In Part Energy Management of HEVs of this thesis, a high-fidelity parallel Through-The-Road (TTR) HEV model is developed to study and test conventional control strategies. The traditional control strategies serve as a guide for developing novel heuristic control strategies. The Equivalent Consumption Minimisation Strategy (ECMS) is an optimisation-based control strategy used as the benchmark in this part of the work. A family of rule-based energy management strategies is proposed for parallel HEVs, including the Torque-levelling Threshold-changing Strategy (TTS) and its simplified version, the Simplified Torque-levelling Threshold-changing Strategy (STTS). The TTS applies a concept of torque-levelling, which ensures the engine works efficiently by operating with a constant torque as the load demand crosses a certain threshold, unlike the load-following approach commonly used. However, the TTS requires finely tuned constant torque and threshold parameters, making it unsuitable for real-time applications. To address this, two feedback-like updating laws are incorporated into the TTS to determine the constant torque and threshold online for real-time applications. Real-time versions of these strategies, Real-time Torque-levelling Threshold-changing Strategy (RTTS) and Real-time Simplified Torque-levelling Threshold-changing Strategy (RSTTS) are developed using a novel Driving Pattern Recognition (DPR) algorithm. The effectiveness of the RTTS is demonstrated by implementing it on a high-fidelity parallel hybrid passenger car and benchmarking it against ECMS. In Part Energy Management of EVs of the thesis, a low-fidelity model of a novel EV powertrain with two electric propulsion systems, one at each axle, has been developed to study and test its energy management with one of the main conventional optimal control methods, Dynamic Programming (DP). The EV model uses two differently sized traction motors at the front and rear axles. The thermal dynamics of the utilised Permanent Magnet Synchronous Motors (PMSMs) are studied. DP is first implemented onto the Baseline model that does not include any PMSM thermal dynamics, referred to as the Baseline DP, which acts as a benchmark since it is the conventional case. The thermal dynamics of the traction motors are then introduced in the second DP problem formulation, referred to as the Thermal DP, which is compared against the Baseline DP to evaluate the possible benefits of energy efficiency by the more informed energy management optimisation formulation. The best method is chosen to include these thermal dynamics in the overall energy management control strategy without significantly compromising computational time.Open Acces

Autonomous Vehicle and Smart Traffic

Long-term forecasting of technology has become extremely difficult due to the rapid realization of any suggested idea. Communication and software technologies can compensate for the problems that may arise during the transition period between idea generation and realization. However, this rapid process can cause problems for the automotive industry and transportation systems.Autonomous vehicles are currently a hot topic within the transportation sector. This development is related to the compatibility of vehicles of the near future with the development of the infrastructure on which these vehicles will be based. There are certain problems regarding the solutions that are currently being worked on, such as how autonomous should vehicles be, their control mechanisms, driving safety, energy requirements, and environmental use. The problem is not just about the design of autonomous vehicles. The user transportation systems of these vehicles also need problem-free solutions. The problem should not only be seen as financial because sociological effects are an important part of this feature.In this book, valuable research on the modeling, systems, transportation, technological necessity, and logistics of autonomous vehicles is presented. The content of the book will help researchers to create ideas for their future studies and to open up the discussion of autonomous vehicles

Critical Aspects of Electric Motor Drive Controllers and Mitigation of Torque Ripple - Review

Electric vehicles (EVs) are playing a vital role in sustainable transportation. It is estimated that by 2030, Battery EVs will become mainstream for passenger car transportation. Even though EVs are gaining interest in sustainable transportation, the future of EV power transmission is facing vital concerns and open research challenges. Considering the case of torque ripple mitigation and improved reliability control techniques in motors, many motor drive control algorithms fail to provide efficient control. To efficiently address this issue, control techniques such as Field Orientation Control (FOC), Direct Torque Control (DTC), Model Predictive Control (MPC), Sliding Mode Control (SMC), and Intelligent Control (IC) techniques are used in the motor drive control algorithms. This literature survey exclusively compares the various advanced control techniques for conventionally used EV motors such as Permanent Magnet Synchronous Motor (PMSM), Brushless Direct Current Motor (BLDC), Switched Reluctance Motor (SRM), and Induction Motors (IM). Furthermore, this paper discusses the EV-motors history, types of EVmotors, EV-motor drives powertrain mathematical modelling, and design procedure of EV-motors. The hardware results have also been compared with different control techniques for BLDC and SRM hub motors. Future direction towards the design of EV by critical selection of motors and their control techniques to minimize the torque ripple and other research opportunities to enhance the performance of EVs are also presented.publishedVersio

MODELING, SIMULATION AND CONTROL OF HYBRID ELECTRIC VEHICLE DRIVE WHILE MINIMIZING ENERGY INPUT REQUIREMENTS USING OPTIMIZED GEAR RATIOS

This project was conducted to analyze (model and simulate) and optimize an electric motor based drive system to propel a typical passenger vehicle in an urban driving environment. Although there are many HEV and EV type systems on the market today, this paper chose the Toyota Prius HEV system as a baseline using a brushless AC motor. Although a vehicle can be driven many ways, a more standardized Urban Dynamometer Driving Schedule, UDDS, was chosen to simulate real driving conditions. This schedule is determined by the US Environmental Protection Agency, EPA, and is intended to represent the city driving conditions for a typical passenger vehicle in a city environment. A high level modeling and simulation approach for vehicle and motor drive was taken to focus on motor operation and gear ratios from the electric to the mechanical drive system. Vehicle battery being the limiting factor in the range of the HEV vehicle, the energy usage of the battery was optimized to ensure lowest energy dissipation, thus gaining the most mileage out of the vehicle. How to maximize the drive mileage for a given battery size? There are multiple dynamic factors that affect the battery usage and efficiency. Factors such as road conditions, vehicle speed, weather, weight, and aerodynamics are amongst the many that govern battery mileage. Gear ratios and selection also play a crucial role in the loading and efficiency of the motor, thus affecting the battery mileage. In this project, the gear ratios between the electric motor and the vehicle drive shaft were the focus for this optimization. As part of the overall system model, gears and gear ratios were modeled and simulated to determine their optimum ratios for finding the minimum energy usage point for the battery

Sähköauton energiatehokkuuden parantaminen kaksiportaisen vaihdelaatikon avulla

Road transportation is one of the most significant carbon dioxide emission sources and about one tenth of European Union region emissions are produced by passenger cars. These emissions have been reduced successfully in Finland and also on European Union region and so far, the set goals have been reached. Car manufacturers have developed internal combustion engines which produce less emissions and this has reduced emissions of new registered cars. Nevertheless, there is limits to internal combustion engine development and emissions cannot be reduced infinitely with this development. Therefore, the number of cars using alternative fuels and energy sources has to grow. Electricity as an alternative fuel has been a choice in vehicle industry for a while. Limited driving range with a single battery charge has been a major barrier in electric vehicle fleet growth. Driving range can be extended by increasing battery capacity but there is volume, weight and cost boundaries that limit battery size. One option for increasing driving range is improving the energy efficiency of the electric vehicle when the on-board battery energy would be utilized more efficiently. This research focuses on improving electric vehicle energy efficiency with two-speed gearbox. Traditionally, the electric motor of an electric vehicle is coupled to driving wheels with a single-speed gearbox. Electric motor as a traction motor enables such drivetrain but with a single-speed gearbox the electric motor must operate in wide speed range. The use of wide speed range forces the motor to work in non-optimal speeds which effects on its energy efficiency. The possible energy efficiency improvement of electric vehicle with multi-speed gearbox is examined in this research. The benefits of two-speed gearbox were evaluated based on the simulation results provided by a developed simulation model. Evaluations were done by comparing the energy consumptions of the reference model to the model that utilizes a two-speed gearbox. Simulations also included an optimization study for determining the optimal gear ratios in order to minimize energy consumption. The results reveal that it is possible to improve energy efficiency with two-speed gearbox but it is heavily dependent on the motor efficiency map which in turn depends on the electric motor type. The benefit of a two-speed gearbox was slightly better in higher speed driving cycles.Liikenne on yksi merkittävimmistä hiilidioksidipäästöjä aiheuittavista lähteistä ja Euroopan Unionin alueella noin kymmenesosa kaikista päästöistä on peräisin henkilöautoista. Liikenteen päästöjä on rajoitettu onnistuneesti ja asetettuihin tavoitteisiin on toistaiseksi päästy niin Suomen kuin Euroopan Unionin osalta. Ajoneuvovalmistajat ovat onnistuneet kehittämään entistä vähäpäästöisempiä polttomoottoreita, mikä näkyy uusien autojen päästöjen pienentymisenä. Polttomoottorien kehitykselle on kuitenkin rajansa eikä liikenteen päästöjä voi rajattomasti pienentää tämän kehityksen avulla, joten vaihtoehtoisia polttoaineita käyttävien ajoneuvojen määrää on lisättävä. Sähkö vaihtoehtoisena polttoaineena on ollut jo pitkää ajoneuvotekniikan käytössä. Sähköautojen merkittävän lisääntymisen esteenä on kuitenkin ollut suhteellisen lyhyt ajomatka yhdellä latauksella, mikä on vaikuttanut vahvasti kuluttajien ostopäätöksiin. Ajomatkaa voidaan kasvattaa akkukapasiteettia lisäämällä, mutta koko ja hinta rajoittavat akkukapasiteetin kasvua. Yksi keino saavutettavan ajomatkan lisäämiseksi on parantaa sähköauton energiatehokkuutta, jolloin yhä suurempi osa mukana olevasta energiasta hyödynnetään ajoneuvon liikuttamiseen. Tässä tutkimuksessa keskitytään sähköauton energiatehokkuuden parantamisen tutkimiseen kaksiportaisen vaihdelaatikon avulla. Perinteisesti sähköautoissa on käytetty kiinteällä välityssuhteella olevaa vaihdetta moottorin ja vetävien pyörin välillä. Voimanlähteenä sähkömoottori mahdollistaa kyseisen voimalinjan, mutta tällöin sähkömoottori toimii laajalla kierroslukualueella, jolloin se ei toimi sen parhaalla mahdollisella hyötysuhteella. Tässä tutkimuksessa tutkitaan simulointien avulla kaksiportaisen vaihteiston vaikutusta sähkömoottorin hyötysuhteeseen ja sen vaikutusta sähköauton energiatehokkuuteen. Tutkimus suoritettiin simulointimallilla, jonka avulla kaksiportaisen vaihteiston hyötyjä voitiin arvioida. Arviointi tehtiin vertailemalla energiankulutusta referenssimallin ja kaksiportaisen vaihteiston sisältävän mallin välillä. Työ sisälsi myös optimoinnin, jolla pyrittiin löytämään välityssuhteet energiankulutuksen minimoimiseksi. Työn tuloksista nähdään, että kaksiportaisen vaihteiston avulla saavutetaan parempi energiatehokkuus, mutta tulokset ovat voimakkaasti riippuvia käytettävän moottorin hyötysuhdekartasta, joka puolestaan riippuu moottorityypistä. Kaksiportaisen vaihteiston hyödyt tulivat paremmin esiin ajosykleillä, joissa on korkeampia ajonopeuksia

Hybrid electric vehicle fuel minimization by DC-DC converter dual-phase-shift control

The paper introduces an advanced DC-link variable voltage control methodology that improves significantly the fuel economy of series Hybrid Electric Vehicles (HEVs). The DC-link connects a rectifier, a Dual Active Bridge (DAB) DC-DC converter and an inverter, interfacing respectively the two sources and the load in a series HEV powertrain. The introduced Dual Phase Shift (DPS) proportional voltage conversion ratio control scheme is realized by manipulating the phase shifts of the gating signals in the DAB converter, to regulate the amount of DAB converter power flow in and out of the DC-link. Dynamic converter efficiency models are utilized to account for switching, conduction, copper and core losses. The control methodology is proposed on the basis of improving the individual efficiency of the DAB converter but with its parameters tuned to minimize the powertrain fuel consumption. Since DPS control has one additional degree of freedom as compared to Single Phase Shift (SPS) voltage control schemes, a Lagrange Multiplier optimization method is applied to minimize the leakage inductance peak current, the main cause for switching and conduction losses. The DPS control scheme is tested in simulations with a full HEV model and two associated conventional supervisory control algorithms, together with a tuned SPS proportional voltage conversion ratio control scheme, against a conventional PI control in which the DC-link voltage follows a constant reference. Nonlinear coupling difficulties associated with the integration of varying DC-link voltage in the powertrain are also exposed and addressed

Field weakening and sensorless control solutions for synchronous machines applied to electric vehicles.

184 p.La polución es uno de los mayores problemas en los países industrializados. Por ello, la electrificación del transporte por carretera está en pleno auge, favoreciendo la investigación y el desarrollo industrial. El desarrollo de sistemas de propulsión eficientes, fiables, compactos y económicos juega un papel fundamental para la introducción del vehículo eléctrico en el mercado.Las máquinas síncronas de imanes permanentes son, a día de hoy la tecnología más empleada en vehículos eléctricos e híbridos por sus características. Sin embargo, al depender del uso de tierras raras, se están investigando alternativas a este tipo de máquina, tales como las máquinas de reluctancia síncrona asistidas por imanes. Para este tipo de máquinas síncronas es necesario desarrollar estrategias de control eficientes y robustas. Las desviaciones de parámetros son comunes en estas máquinas debido a la saturación magnética y a otra serie de factores, tales como tolerancias de fabricación, dependencias en función de la temperatura de operación o envejecimiento. Las técnicas de control convencionales, especialmente las estrategias de debilitamiento de campo dependen, en general, del conocimiento previo de dichos parámetros. Si no son lo suficientemente robustos, pueden producir problemas de control en las regiones de debilitamiento de campo y debilitamiento de campo profundo. En este sentido, esta tesis presenta dos nuevas estrategias de control de debilitamiento de campo híbridas basadas en LUTs y reguladores VCT.Por otro lado, otro requisito indispensable para la industria de la automoción es la detección de faltas y la tolerancia a fallos. En este sentido, se presenta una nueva estrategia de control sensorless basada en una estructura PLL/HFI híbrida que permite al vehículo continuar operando de forma pseudo-óptima ante roturas en el sensor de posición y velocidad de la máquina eléctrica. En esta tesis, ambas propuestas se validan experimentalmente en un sistema de propulsión real para vehículo eléctrico que cuenta con una máquina de reluctancia síncrona asistidas por imanes de 51 kW