Several factors including fossil fuels scarcity, prices volatility, greenhouse gas emissions or current pollution levels in metropolitan areas are forcing the development of greener transportation ...systems based on more efficient electric and hybrid vehicles. Most of the current hybrid electric vehicles use electric motors containing powerful rare-earth permanent magnets. However, both private companies and estates are aware of possible future shortages, price uncertainty and geographical concentration of some critical rare-earth elements needed to manufacture such magnets. Therefore, there is a growing interest in developing electric motors for vehicular propulsion systems without rare-earth permanent magnets. In this paper this problematic is addressed and the state-of-the-art of the electric motor technologies for vehicular propulsion systems is reviewed, where the features required, design considerations and restrictions are addressed.
Layered lithium nickel-rich oxides, LiNi1−xMxO2 (M=metal), have attracted significant interest as the cathode material for rechargeable lithium batteries owing to their high capacity, excellent rate ...capability and low cost. However, their low thermal-abuse tolerance and poor cycle life, especially at elevated temperature, prohibit their use in practical batteries. Here, we report on a concentration-gradient cathode material for rechargeable lithium batteries based on a layered lithium nickel cobalt manganese oxide. In this material, each particle has a central bulk that is rich in Ni and a Mn-rich outer layer with decreasing Ni concentration and increasing Mn and Co concentrations as the surface is approached. The former provides high capacity, whereas the latter improves the thermal stability. A half cell using our concentration-gradient cathode material achieved a high capacity of 209 mA h g−1 and retained 96% of this capacity after 50 charge-discharge cycles under an aggressive test profile (55 C between 3.0 and 4.4 V). Our concentration-gradient material also showed superior performance in thermal-abuse tests compared with the bulk composition LiNi0.8Co0.1Mn0.1O2 used as reference. These results suggest that our cathode material could enable production of batteries that meet the demanding performance and safety requirements of plug-in hybrid electric vehicles.
The electric motor market has witnessed a major change in the last decade in several aspects: in structure, with company mergers contributing to a more global market, in content with ...energy-efficiency policies, and in its economy due to increasing electricity prices, all aspects contributing to push the market towards more energy-efficient electric motors.
Additionally, the growing market penetration of Variable Speed Drives (VSD), introducing large energy savings in systems with variable loads, was accompanied by a growing concern over their operating efficiency in full and especially in part-load, as well as in stand-by mode.
A Motor Driven Unit (MDU) consists of the core components of a motor system: electric motor, variable speed drive (VSD), mechanical transmission and end-use application, like a pump or fan. Regulating the entire Motor Driven Unit (MDU) would translate into 1400 TWh of cost-effective electricity savings (7% of the World motor systems electricity consumption), with a corresponding reduction in emissions of 469 Mton of CO2eq by 2040. Even larger potential energy savings can be made available by the optimization of the entire motor systems, which translates into 3100 TWh of global electricity savings by 2040. Still to date, Minimum Energy Performance Standards (MEPS) have been mostly targeted at individual components only. Difficulties arise in the standardization of measuring and classifying the entire MDU but the larger energy savings achievable by the motor system is leading to the launch a combined system standard by the International Electrotechnical Committee (IEC) and the International Organization for Standardization (ISO).
MEPS and standardization at the component and MDU level must be carefully complemented to achieve the maximum energy savings and carbon emission reductions.
This paper carries out novel technical, economic and environmental analyses of introducing new policy measures (standards and MEPS) for both individual components and MDUs.
•A review of international regulatory options for electric motors is given.•An analysis of the environmental impacts and electricity consumption of motors and its improvement potential is made.•A review of new technology developments in motors and drives is made.•Impact on global electricity consumption and GHG emissions of introducing system energy efficiency regulation is estimated.•Current standardisation status is analysed and challenges for future system approach are identified.
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Sustainable management strategies for securing long–term supply of rare earth elements is priority for Europe due to a complex and interlinked production chain and its dependence on ...Chinese export. Among rare earth elements, neodymium captured most attention due to its essential role in a wide spectrum of applications including green–energy technologies such as wind turbines and electric vehicles. Being complementary to primary production, end–of–life recycling would diversify neodymium supply, relieve the Chinese dominance on primary production and contrast the balance problem. However, neodymium recycling at end–of–life is not yet in place.
In this work, we developed a dynamic material flow model to investigate neodymium stocks and flows in the EU–28 to 2016. The analysis enabled a detailed investigation of secondary sources of neodymium, which set essential boundary conditions for material recovery and recycling. We found that roughly up to 50% of the annual neodymium demand in the EU–28 could be met by domestic secondary supply, if latent recycling potentials were turned into actual capacity. Significant energy savings and GHG emissions cut could be also attained. However, product design, end–of–life collection, and scrap price issues are primary obstacles to neodymium recovery. Thus, unless going beyong those limits, establishing and maintaining a sustainable recycling chain for neodymium in the EU–28 will remain problematic.
•Hybrid intelligent model for classification of ball bearing faults.•Entropic features extracted from vibration signals.•Tested on both benchmark and real-world dataset.•Good results obtained ...including explanatory rules from decision trees.
In this paper, classification of ball bearing faults using vibration signals is presented. A review of condition monitoring using vibration signals with various intelligent systems is first presented. A hybrid intelligent model, FMM-RF, consisting of the Fuzzy Min-Max (FMM) neural network and the Random Forest (RF) model, is proposed. A benchmark problem is tested to evaluate the practicality of the FMM-RF model. The proposed model is then applied to a real-world dataset. In both cases, power spectrum and sample entropy features are used for classification. Results from both experiments show good accuracy achieved by the proposed FMM-RF model. In addition, a set of explanatory rules in the form of a decision tree is extracted to justify the predictions. The outcomes indicate the usefulness of FMM-RF in performing classification of ball bearing faults.
'Electric Motor Control' introduces practical drive techniques of electric motors to enable stable and efficient control of many application systems, also covering basic principles of ...high-performance motor control techniques, driving methods, control theories and power converters.
Motors systems are a major electricity consumer (about 70% of the industrial electricity consumption and about 35% in the non-residential buildings sector). Several studies showed the very large ...energy saving potential deriving from motor improved efficiency.
After a period of Voluntary Agreement with a somehow limited impact, the EU introduced in 2009 Minimum Efficiency Performance Standards (MEPS) with the Commission Regulation 640/2009, which specifies requirements regarding Ecodesign of electrical motors and the use of electronic speed drives (VSD). The Regulation is based on the findings of the first Energy using Products (EuP) study on motors (Lot 11), which highlighted the importance of introducing Minimum Efficiency Performance Standards (MEPS) relating to these products in the EU.
A new Ecodesign preparatory study (European Commission - Lot 30 on special motors and drives) has since then been carried out to evaluate the possibility of extending the scope of the Regulation to motors outside the current power range and to technologies other than three-phase induction motors.
Six policy options (PO) were identified, as well as their possible implementation timelines, that will lead to the reduction of environmental impacts taking into consideration the Life Cycle Cost and the best available technologies in the market.
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•Climate change and human toxicity important in LCA of electrical traction machines.•Complete manufacturing range within 1.7–2.0 g CO2-eq./km for all studied motors.•Copper production ...is significant for toxicity impacts and effects on human health.•Design focus: energy efficiency, housings, end-windings, laminates and disassembly.
Ongoing development of electrified road vehicles entails a risk of conflict between resource issues and the reduction of greenhouse gas emissions. In this study, the environmental impact of the core design and magnet material for three electric vehicle traction motors was explored with life cycle assessment (LCA): two permanent magnet synchronous machines with neodymium-dysprosium-iron-boron or samarium-cobalt magnets, and a permanent magnet-assisted synchronous reluctance machine (PM-assisted SynRM) with strontium-ferrite magnets. These combinations of motor types and magnets, although highly relevant for vehicles, are new subjects for LCA. The study included substantial data compilation, machine design and drive-cycle calculations. All motors handle equal take-off, top speed, and driving conditions. The production (except of magnets) and use phases are modeled for two countries – Sweden and the USA – to exemplify the effects of different electricity supply. Impacts on climate change and human toxicity were found to be most important. Complete manufacturing range within 1.7–2.0 g CO2-eq./km for all options. The PM-assisted SynRM has the highest efficiency and lowest emissions of CO2. Copper production is significant for toxicity impacts and effects on human health, with problematic emissions from mining. Resource depletion results are divergent depending on evaluation method, but a sensitivity analysis proved other results to be robust. Key motor design targets are identified: high energy efficiency, slender housings, compact end-windings, segmented laminates to reduce production scrap, and easy disassembly.
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