Optimization of motor and gearbox for an ultra light electric vehicle

The integrated design of the drivetrain of a single person ultra light electric vehicle powered by batteries is optimized towards high efficiency and low mass. The drivetrain of each front wheel consists of an outer rotor permanent magnet synchronous motor (PMSM), a gearbox and the power electronics with converter and control print. The complete drivetrain is optimized for the New European Driving Cycle and the Federal Test Procedure. For the optimization of the complete drivetrain analytical models are used to calculate the losses and the efficiency. The analytical models are fast, and useful for designing a good PMSM in combination with a gearbox. The optimization of the drivetrain over the driving cycles makes it possible to choose the optimal combination of motor and gearbox for different gear ratios in order to have high efficiency and low weight. Comparing a single-stage gearbox with a twostage gearbox, a single-stage gearbox has a higher efficiency, but also a higher weight than a two-stage gearbox with the same properties. The optimization of the dynamic behavior of the drivetrain over the driving cycles yields a compromise between the total efficiency and the total mass of the drivetrain. The optimum choice will depend on the intended use of the vehicle (drive cycle)

Advanced gearbox technology

An advanced 13,000 HP, counterrotating (CR) gearbox was designed and successfully tested to provide a technology base for future designs of geared propfan propulsion systems for both commercial and military aircraft. The advanced technology CR gearbox was designed for high efficiency, low weight, long life, and improved maintainability. The differential planetary CR gearbox features double helical gears, double row cylindrical roller bearings integral with planet gears, tapered roller prop support bearings, and a flexible ring gear and diaphragm to provide load sharing. A new Allison propfan back-to-back gearbox test facility was constructed. Extensive rotating and stationary instrumentation was used to measure temperature, strain, vibration, deflection and efficiency under representative flight operating conditions. The tests verified smooth, efficient gearbox operation. The highly-instrumented advanced CR gearbox was successfully tested to design speed and power (13,000 HP), and to a 115 percent overspeed condition. Measured CR gearbox efficiency was 99.3 percent at the design point based on heat loss to the oil. Tests demonstrated low vibration characteristics of double helical gearing, proper gear tooth load sharing, low stress levels, and the high load capacity of the prop tapered roller bearings. Applied external prop loads did not significantly affect gearbox temperature, vibration, or stress levels. Gearbox hardware was in excellent condition after the tests with no indication of distress

Energy efficiency measurement procedure for gearboxes in their entire operating range

Over the last decade, forced regulations and a growing social awareness with respect to energy efficiency have resulted in a renewed interest in the research for high efficient electrical machines. When an electrical motor is coupled to a machine, in many cases a gearbox or belt transmission is used. Research shows a lack of information on energy efficiency of these components. In comparison to electrical motors and drives, there is very few regulation and if efficiency values can be found in catalogues, there is no regulated test procedure available to validate the data. As a result, the reliability of these efficiency values is unknown and comparison between manufacturers and technologies is impossible. In this paper a test bench is proposed to measure the energy efficiency of a gearbox with an accuracy up to 0.4%. The test bench is used to measure the efficiency of gearboxes in their entire speed and torque range. Contour maps are used to visualize these measurement results. Moreover, a measurement campaign using different gearboxes is carried out to compare the energy efficiency in the manufacturers catalogue and the measured efficiency

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

Investigating the Effect of Water Contamination on Gearbox Lubrication based on Motor Control Data from a Sensorless Drive

Water is one of the most significant destructive contaminations to lubricants which in turn lead to more power consumption and early damage to rotating machines. This study explores the effect of water contents in gearbox lube oil on the responses of electrical supply parameters. A two stage gearbox based mechanical transmission system driven by a sensorless variable speed drive (VSD) is utilised to investigate experimentally any measurable changes in these signals that can be correlated with water contamination levels. Results show that the supply parameters obtained from both external measurements and the VSD control data can be correlated to the contamination levels of oil with water and hence can be based on for an instant diagnosis of water contamination. Particularly, the voltage and hence the power responses are more sensitive to the water contents than that of current because the VSD regulates more the voltage to adapt the small load changes due to the water induced lubrication degradation. Simultaneously, vibration also shows changes which agree with that of power supply parameters

Analysis of the efficiency of wind turbine gearboxes using the temperature variable

The aim of this paper is to evaluate how lubricant selection affects gearbox efficiency and overall energy production by analysing real data from wind farms, monitored and controlled by a Supervisory Control and Data Acquisition (SCADA system). The turbines analysed worked with two or more oil types for the same amount of hours, which allowed to establish relations between the active power curves and wind velocity; oil temperature inside gearboxes and wind velocity; and oil temperature inside gearboxes and active power production. The results of this study evidenced a direct relation between oil characteristics and energy efficiency i.e. gearboxes working with mineral oil perform better then gearboxes working with synthetic oils. Those differences can be significant in terms of active power production. Also, it was observed oil degradation as function of temperature increase, with changes on viscosity, which reveals that temperature behaviour along the active power curve is strongly related to oil' characteristics. (C) 2018 Elsevier Ltd. All rights reserved.Agência financiadora Portuguese Foundation for Science and Technology (FCT) PTDC/AAG-TEC/1710/2014 MONITOR project - Atlantic Area EAPA_333/2016 Portuguese Foundation for Science and Technology under the Portuguese Researchers' Programme 2014 IF/00286/2014/CP1234 Marie Sklodowska-Curie Actions of the European Union's H2020-MSCA-IF-EF-RI-2016/under REA - 748747info:eu-repo/semantics/publishedVersionhttp://creativecommons.org/licenses/by/4.0

Mass-dimensional charakteristics of wind-driven powerplants with horizontal axis of rotation of wind wheel

В роботі проведено аналіз базових конструкцій вітроенергетичних установок з горизонтальною віссю обертання вітроколеса. Проведено порівняння маси, об'єму та енергоефективності цих установок. З'я-совано що найбільшу масу має вітроустановка, виконана за безредукторної схемою і вона ж забезпечує отримання найбільшого к.к.д. Схеми з редуктором і генератором на осі вітроколеса дозволяють майже в два рази зменшити масу вітроустановки в порівнянні з безредукторної схемою при близькому, хоча дещо меншому значенні к.к.д. Найменшу масу мають генератори вітроустановки у разі розміщення їх на лопатях вітроколеса, проте к.к.д. установки помітно менше в порівнянні з безредукторної і редукторного схемами. Схема з безконтактним струмознімачем дозволить підвищити надійність роботи вітроустановки і рівень вихідної напруги при зниженні маси її елементів порівняно редукторних схем. Комбінована схема вітроустановки дає можливість значно знизити її масу в порівнянні з редукторні схемами і отримати два незалежних джерела електроенергії..В работе проведен анализ базовых конструкций ветроэнергетических установок с горизонтальной осью вращения ветроколеса. Проведено сравнение массы, объема и энергоэффективности этих установок. Выяснено что наибольшую массу имеет ветроустановка, выполненная по безредукторной схеме и она же обеспечивает получение наибольшего к.п.д. Схемы с редуктором и генератором на оси ветроколеса позволяют почти в два раза уменьшить массу ветроустановки по сравнению с безредукторной схемой при близком, хотя несколько меньшем значении к.п.д. Наименьшую массу имеют генераторы ветроустановки в случае размещения их на лопастях ветроколеса, однако к.п.д. установки заметно меньше по сравнению с безредукторной и редукторными схемами. Схема с бесконтактным токосъемником позволит повысить надежность работы ветроустановки и уровень выходного напряжения при снижении массы её элементов сравнительно редукторных схем. Комбинированная схема ветроустановки дает возможность значительно снизить её массу по сравнению с редукторными схемами и получить два независимых источника электроэнергии

Development of Urban Electric Bus Drivetrain

The development of the drivetrain for a new series of urban electric buses is presented in the paper. The traction and design properties of several drive variants are compared. The efficiency of the drive was tested using simulation calculations of the vehicle rides based on data from real bus lines in Prague. The results of the design work and simulation calculations are presented in the paper

Floating Point Representations in Quantum Circuit Synthesis

We provide a non-deterministic quantum protocol that approximates the single qubit rotations R_x(2a^2 b^2)$ using R_x(2a) and R_x(2b) and a constant number of Clifford and T operations. We then use this method to construct a "floating point" implementation of a small rotation wherein we use the aforementioned method to construct the exponent part of the rotation and also to combine it with a mantissa. This causes the cost of the synthesis to depend more strongly on the relative (rather than absolute) precision required. We analyze the mean and variance of the \Tcount required to use our techniques and provide new lower bounds for the T-count for ancilla free synthesis of small single-qubit axial rotations. We further show that our techniques can use ancillas to beat these lower bounds with high probability. We also discuss the T-depth of our method and see that the vast majority of the cost of the resultant circuits can be shifted to parallel computation paths.Comment: Comments welcom

Investigations on the performances of the electrical generator of a rim-driven marine current turbine”

In this paper, the electrical generator of a rim-driven horizontal-axis current turbine is modeled in detail. Its main characteristics and performances are evaluated (efficiency, mass, cost, etc). This generator is of permanent magnet direct-driven synchronous type and is connected to a variable speed power electronics drive. It is then compared to a more traditional technology (a pod generator) in terms of mass and cost for a common set of specification. In addition, due to the specific geometry of the machine, the use of low-cost ferrite magnets is investigated in place of NdFeB magnets