Search Results (7)

The hybridization of multiple energy sources is crucial for electric vehicles to deliver the same performance as modern fossil fuel-based automobiles. This paper presents a torque and speed control strategy for an electric vehicle DC traction motor by regulating the power flow from two energy sources, namely battery and supercapacitor systems, to resist unpredictable disturbances. A control system with three control loops is applied to regulate the speed of the traction motor. The outer speed control loop is a nonlinear state feedback controller with a disturbance observer, which is capable of handling non-linear systems with unpredictable disturbances. The inner voltage and current control loop are precisely tuned PI controllers. Using an adaptive energy management method that varies depending on the state of charge of the source, the total reference current needed to support the load demand is split between two sources. A laboratory prototype system model is generated, and the performance is analyzed under motoring and regenerative braking conditions. For monitoring and controlling the system, the dSPACE DS1202 real-time simulator is employed. The performance of the proposed control system is evaluated and it is found that the settling time to settle within a tolerance band of 1% is 0.75 s. Full article

Electric vehicles (EVs) are gaining more and more traction as a viable option in the automotive sector. This mode of transportation is currently on track, according to current trends, to totally replace internal combustion engine (ICE) cars in the not-too-distant future. The economic system, the energy infrastructure, and the environment are just a few of the areas where electric vehicles could have a major impact. The transportation industry produces the second-most carbon dioxide gas from the combustion of fossil fuels, making it the second-highest contributor to global warming. A lot of people are looking to EVs, or electric vehicles, as a possible game-changing answer to this problem. Since an electric motor drives the electric vehicle’s propeller instead of an internal combustion engine, electric vehicles can reduce their carbon dioxide (CO₂) emissions compared to traditional automobiles. If coupled with renewable energy sources, EVs might theoretically become emission-free automobiles. In this paper, we will examine the various EV drive circuit types, including their construction and the benefits and drawbacks of employing each. This article discusses the current state of battery technology with an emphasis on EV batteries. This article discusses the best electric motor for EVs in terms of efficiency, power density, fault tolerance, dependability, cost, and more. Next, we conduct in-depth research into the difficulties and potential rewards of EV adoption in the future. While improvements in areas like charging times and battery performance are encouraging, government regulation of EVs remains a big non-technical barrier. Full article

High-performance Nd-Fe-B-based rare-earth permanent magnets play a crucial role in the application of traction motors equipped in new energy automobiles. In particular, the anisotropic hot-deformed (HD) Nd-Fe-B magnets prepared by the hot-press and hot-deformation process show great potential in achieving high coercivity due to their fine grain sizes of 200–400 nm, which are smaller by more than an order of magnitude compared to the traditional sintered Nd-Fe-B magnets. However, the current available coercivity of HD magnets is not as high as expected according to an empirical correlation between coercivity and grain size, only occupying about 25% of its full potential of the anisotropy field of the Nd₂Fe₁₄B phase. For the sake of achieving high-coercivity HD magnets, two major routes have been developed, namely the grain boundary diffusion process (GBDP) and the dual alloy diffusion process (DADP). In this review, the fundamentals and development of the HD Nd-Fe-B magnets are comprehensively summarized and discussed based on worldwide scientific research. The advances in the GBDP and DADP are investigated and summarized based on the latest progress and results. Additionally, the mechanisms of coercivity enhancement are discussed based on the numerous results of micromagnetic simulations to understand the structure–property relationships of the HD Nd-Fe-B magnets. Lastly, the magnetization reversal behaviors, based on the observation of magneto-optic Kerr effect microscopy, are analyzed to pinpoint the weak regions in the microstructure of the HD Nd-Fe-B magnets. Full article

A demand for high efficiency traction motors has been accelerated by the promotion of electrified vehicles, such as battery and fuel cell electric vehicles. As a part of development of the high efficiency traction motor, this paper reports a comparative study on two kinds of hybrid excitation flux switching motors (HEFSM) as a variable flux machine. One is the conventional HEFSM, which consists of a stator with constantly magnetized-permanent magnets, field excitation coils (FECs) and three-phase armature windings, and a rotor with salient poles like a switched reluctance motor. The other is a HEFSM employing variably magnetizable-permanent magnets (VM-PMs) that replace a part in the FEC slot area in the conventional one. Based on the variable magnetization nature of VM-PMs, the latter HEFSM promises that the replacement of magnetomotive force (mmf) of FECs with that of the VM-PMs makes the motor efficiency better at both low- and high-speed under the low-torque condition, that is, at both urban driving or highway cruising. To verify that, finite element analysis- (FEA)-based design simulations, as well as experimental performance evaluations for the two kinds of HEFSM, were conducted under reasonable dimensional and electrical constraints. As a result, it is shown that the latter HEFSM can achieve higher motor efficiency at the low-torque and high-speed region while keeping the motor efficiency at the low-torque and low-speed region. Full article

This paper aims at providing a multisource data analysis, including direct data collection, focussed on daily average distances covered with motorized mobility. Its results can be used as a basis for policies involving a shift towards new propulsions, electric motors or hybrid electric vehicles (HEV) for road vehicles. A number of variables influence the propensity of drivers to use electric traction, even the option of plug-in hybrid electric vehicles (PHEV). This paper addresses one of these variables: the compliancy of electric traction—regarding both hybrid plug-in solutions and full-electric vehicles, in addition to the autonomy of batteries (range)—with the daily travels by road vehicles, mainly by automobiles. We want to understand whether the constraints leading towards a greater independence from crude oil rather than constraints concerning emissions, mainly in urban contexts, might be compliant with the habitual daily trips of drivers. We also want to understand if these daily trips have varied much during recent years and the consequences they may have on operational costs of plug-in automobiles. After introducing a general overview of road-motorized mobility in Italy, the paper compares data from other studies to provide an indication of average daily driving distances. This reveals how different recent analyses converge on a limited range of average road distances covered daily by Italians, which is compliant with ranges allowed by electric batteries, provided that their low energy density in comparison with that of oil-derived fuels do not arrive to imply a significant increase in vehicle mass. Subsequently, average distances in some EU countries are taken from the literature, and the results are also compared with U.S. data. The study extends the analysis of trends on the use of automobiles and road-vehicles to the international context by also addressing average daily distances covered for freight transport in some EU countries, thereby providing a further basis for comparison and for understanding whether the daily motorized mobility can be considered as a stable phenomenon. Finally, an analysis is provided of the economic operational advantages from using plug-in vehicles. Full article

Generally, design of the parts of an automobile is restricted by space especially components assembled in the engine room. Therefore traction motor for hybrid electric vehicle is designed by interior permanent magnet synchronous motor (IPMSM). The IPMSM has high power density and efficiency because it generates not only magnetic torque but also reluctance torque. However, IPMSM is difficult to design due to magnetic saturation and lots of analysis methods are required. Equivalent circuit analysis (ECA) is one of the design methods of IPMSM and it is generally used for characteristics analysis. Using the ECA, we can calculate the characteristics quickly. However, ECA can not estimate line current exactly because of saturation of magnetic core and flux weakening control. In order to perform the ECA exactly, calculation of parameters such as phase resistance, d- and q-axis inductance and no-load linkage flux are important. The phase resistance is simply calculated by using linear equation which is geometrical problem. However, dand q-axis inductance is nonlinear problem which is varied with current level and current angle. Therefore, nonlinear finite element analysis is necessary. Conventional ECA is considered only d- and q-axis inductance profile but no-load linkage flux is considered as constant value. However, no-load linkage flux of IPMSM is also varied according to current level and current angle similar with d- and q-axis inductance profile. Therefore, no-load linkage flux profile which is calculated case of current level and current angle should be considered in the ECA. In this paper, the calculation method of no-load linkage flux profile is introduced firstly and then characteristic of specific model is analyzed with proposed method. The result of line current from improved ECA is compared with experimental result and result of conventional ECA. Full article

In electric vehicles that use in-wheel motors, the right and left traction forces become unbalanced if a motor malfunctions by motor lock or loss of traction, generating yaw moment. Control methods were designed to reduce this effect by stopping the motor output on the opposite side of the same axle. By using a prototype “Eliica” car, the maximum yaw rate and lateral acceleration were compared for a breakdown of one motor with the results from the “Sensitivity to lateral wind” indicated in Z108-76 of the Japanese Automobile Standards Organization. Under redundancy control, the test results were confirmed to be below the tolerance limits Full article