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The use of a cobalt-iron (VaCoFe) core is investigated as an alternative to silicon-iron (FeSi) in the design of interior permanent magnet synchronous motors (IPMSM). Considering VaCoFe and FeSi cores, a spoke-type IPMSM geometry is optimized for a torque range up to 40 N·m, providing a general comparative analysis between materials. This is done considering the application of a four-motor competition vehicle's powertrain. A genetic optimization algorithm is coupled to the motor's electromagnetic and thermal hybrid analytical/finite-element model to provide sufficiently accurate results within a feasible time. VaCoFe allows an estimated increase of up to 64% in torque for the same efficiency level, or up to 5% in efficiency for the same torque. After optimization and using a detailed time-dependent model, a potential 3.2% increase in efficiency, a core weight reduction of 4.1%, and a decrease of 9.6% in the motor's core volume were found for the VaCoFe at 20 N·m. In addition, for the same motor volume, the VaCoFe allows an increase of 51.9% in torque with an increase of 1.1% in efficiency when compared with FeSi. [ABSTRACT FROM AUTHOR]

The growing integration of renewable sources with grid poses challenges in the field of voltage and frequency control. This study features combined automatic voltage regulator and load frequency control model of a three-area power system network with each area containing thermal and diesel power plants along with the introduction of solar thermal power plant, wind, and geothermal power plants. The Harris Hawks Optimization (HHO) based centralized Model Predictive Controller (MPC) has been discussed and implemented for the effective and simultaneous control of voltage and frequency in all three areas of the wind integrated power plant. To further deal with increased oscillations in frequency profile of the system caused due to renewable integration, the electric vehicle (EV) participation has been considered in each area to provide an auxiliary control against frequency deviations. Effectiveness of the proposed EV based MPC-HHO algorithm has been successfully verified after adding different nonlinearities, parameter uncertainties, disturbances, and time-delays in the wind integrated power system. [ABSTRACT FROM AUTHOR]

Abstract To control the power hierarchy design of lithium-ion battery (LIB) built-up sets for electric vehicles (EVs), we offer intensive theoretical and experimental sets of choice anode/cathode architectonics that can be modulated in full-scale LIB built-up models. As primary structural tectonics, heterogeneous composite superstructures of full-cell-LIB (anode//cathode) electrodes were designed in closely packed flower agave rosettes TiO2@C (FRTO@C anode) and vertical-star-tower LiFePO4@C (VST@C cathode) building blocks to regulate the electron/ion movement in the three-dimensional axes and orientation pathways. The superpower hierarchy surfaces and multi-directional orientation components may create isosurface potential electrodes with mobile electron movements, in-to-out interplay electron dominances, and electron/charge cloud distributions. This study is the first to evaluate the hotkeys of choice anode/cathode architectonics to assemble different LIB–electrode platforms with high-mobility electron/ion flows and high-performance capacity functionalities. Density functional theory calculation revealed that the FRTO@C anode and VST-(i)@C cathode architectonics are a superior choice for the configuration of full-scale LIB built-up models. The integrated FRTO@C//VST-(i)@C full-scale LIB retains a huge discharge capacity (~ 94.2%), an average Coulombic efficiency of 99.85% after 2000 cycles at 1 C, and a high energy density of 127 Wh kg−1, thereby satisfying scale-up commercial EV requirements.

This study investigates the influence of stator coil pitch on the electromagnetic performance of squirrel‐cage induction machine (IM) with emphasis on the flux‐weakening (FW) capability for electric vehicle applications. Three different winding topologies, obtained by changing the coil pitch, namely integer‐slot distributed winding (ISDW), integer‐slot concentrated winding, and fractional‐slot concentrated winding (FSCW), are studied. Their merits and demerits are revealed by comparing their performances characteristics, including winding harmonic index, total axial length, average torque, torque ripple, power losses, efficiency, and FW capability. It is revealed that due to the very high Magnetomotive force (MMF) harmonics induced in the bar current, the bar copper loss of the IM with FSCW is significant. It is also revealed that the parasitic effects of the double‐layer winding configurations are lower than those of the single‐layer (SL) winding configurations. It is also demonstrated that for the slot/pole/phase combinations lower than two q≤2, the higher the coil pitch, the lower the parasitic effects and the higher the efficiency. Moreover, it is found that the combinations q≥2, especially those having longer coil pitch and higher stator slot number, and the SL combinations offer better FW capability. Finally, the Finite‐element analysis (FEA) results of IM with long‐pitch ISDWs are validated by experimental measurements. [ABSTRACT FROM AUTHOR]

Some key features to be satisfied by electric motors catering a wide range of applications are high specific power, lower manufacturing cost, rugged construction, and fault‐tolerant operation. Switched reluctance motor is one such motor technology satisfying all the above requirements and is an emerging competitor to the induction and permanent magnet motors in domestic, industrial and electric vehicle applications. The present‐day research on this motor is moving towards improving efficiency at lower speeds, power density, and the torque density. Certain challenges in achieving the same are (a) minimising the losses, (b) mitigation of torque ripple, noise, and vibration, and (c) material advancements. A review based on the estimation and mitigation techniques of each of these over the past three to four decades has been dealt with in this study. The salient features and results in each section provide a clear understanding of how each of these challenges can be overcome in the aspect of design and control strategies. [ABSTRACT FROM AUTHOR]

Permanent magnet synchronous motors are widely accepted in automotive applications. The high torque density, high rotational speed with maximum efficiency in electric vehicle applications is technically challenging for motor design. However, these machines are expensive and difficult to work at high-temperature harsh environment due to permanent magnets demagnetisation features. Alternatively, switched reluctance motors can provide similar output characteristics and a wider speed. Thus these are considered to be more fault tolerant and more reliable. This study proposes a 20 kW, three-phase switched reluctance motor and analyse its overall performance and harmonic contents. The study is conducted by optimising the slot filling factor, excitation voltage and switching sequence of an asymmetrical half bridge converter. A finite element model is used to predict the core and copper losses and other influencing parameters. Simulation results are presented and analysed the effectiveness of the proposed switched reluctance motor (SRM).

In electric drive applications that are based on high‐speed induction motors (IMs) with an extended speed range, stator winding pole‐changing is a possible technique to avoid oversizing the driving motor. The electronic pole changing employed in multiphase IMs has gained recent interest because it avoids physical winding reconfiguration. The effective number of poles of the air gap flux distribution can be electronically altered by simply changing the applied current sequence to a multiphase stator. The main problem associated with this technique is the significant increase in machine magnetising current with the increase in effective pole number when conventional multiphase distributed windings are employed. This study proposes a new fractional‐slot concentrated winding layout with a special stator connection suitable for pole‐amplitude modulated IMs that offers a 2:1 pole ratio while maintaining equal magnetising current for both winding pole pairs. Moreover, constant power operation can be achieved for a speed range of over 4 pu. The main concept is discussed and verified through simulations and experimentally. The machine mathematical model and the required vector space decomposition‐based controller are also presented. [ABSTRACT FROM AUTHOR]

Permanent magnet synchronous motors are widely accepted in automotive applications. The high torque density, high rotational speed with maximum efficiency in electric vehicle applications is technically challenging for motor design. However, these machines are expensive and difficult to work at high-temperature harsh environment due to permanent magnets demagnetisation features. Alternatively, switched reluctance motors can provide similar output characteristics and a wider speed. Thus these are considered to be more fault tolerant and more reliable. This study proposes a 20 kW, three-phase switched reluctance motor and analyse its overall performance and harmonic contents. The study is conducted by optimising the slot filling factor, excitation voltage and switching sequence of an asymmetrical half bridge converter. A finite element model is used to predict the core and copper losses and other influencing parameters. Simulation results are presented and analysed the effectiveness of the proposed switched reluctance motor (SRM). [ABSTRACT FROM AUTHOR]

The performance requirement of a squirrel cage induction motor (IM) for application in electric vehicle (EV), with high efficiency, power factor and breakdown torque, is a challenging task for a machine designer. A new 5 hp wide speed operating range IM suitable for EV application has been designed here. The parametric study to analyse the effect of stator and rotor slot dimensions on different performance parameters has been carried out. This parametric study forms the basis of the multi‐objective optimisation problem taken in this study. An evolutionary algorithm has been used for the IM design optimisation and its performance is compared to that of a conventional one. The optimised IM is then fabricated and tested in the laboratory to validate the simulation results. [ABSTRACT FROM AUTHOR]

This paper deals with a new high-voltage-gain zero-current switching bidirectional DC-DC converter for electric vehicles. The hard-switched non-isolated bidirectional converter integrated with auxiliary active switches and resonant elements were designed to attain the zero-current switching turn-off operation in the main IGBTs. This converter has dual characteristics as battery charge (buck) mode and discharge (boost) mode. By individual mode, all the active switches operate under zero-current switching turn-off operation for the minimized turn-off losses. The proposed converter has high voltage gain with reduced turn-off losses when operating in discharge mode and has low output voltage conversion in charge mode. The topology described with the aid of theoretical waveforms were tested using a laboratory prototype 70/300 V, 800 W system functioned under 50 kHz operating frequency. [ABSTRACT FROM AUTHOR]

A charge equalisation controller (CEC) was developed for continuously monitoring individual battery cells and equalising the charge or voltage levels of all cells in a series pack. A charge equalisation control algorithm was developed to equalise undercharged, overcharged, and unprotected cells through the use of a bidirectional fly‐back converter. The equalisation involves charging and discharging by employing constant current–constant voltage and discontinuous current mode proportional–integral (PI) control techniques. Particle swarm optimisation is applied to optimising the PI controller parameters that generate the regulated pulse width modulation switching signal for the converter. A CEC model was applied to 90 lithium‐ion battery cells (nominally 15.5 Ah and 3.7 V each) connected in series. The results showed that the developed CEC model performed well at equalising both undercharged and overcharged cells with ∼92% efficiency and equalised every cell within the safe operation range of 3.73–3.87 V. The developed system realises excellent equalisation speed, a simple design and efficiency with low power loss. Thus, the CEC model has great potential for implementation in real‐world electric vehicle energy storage systems. [ABSTRACT FROM AUTHOR]

Supercapacitor is being widely used in electric transportation applications, particularly in electric vehicles (EVs). In the EV, the supercapacitor mainly serves as energy storage system for accelerating the vehicle and/or capturing the braking energy due to its prominent features such as high power density and long life cycle. However, during the vehicle braking and/or accelerating, deep and fast supercapacitor charging‐discharging cycles increase the electric and thermal stresses on the supercapacitor bank. Under such circumstances, condition monitoring of the supercapacitor bank is essential in EVs for safe operation of the storage system. In this paper, an effective method for condition monitoring and fault diagnosis of the supercapacitor banks is proposed. First, it is shown that the equivalent series resistance (ESR) and double‐layer capacitance (CDL) can be used as the key signatures for indicating the state‐of‐health. Subsequently, the recursive extended least‐square algorithm (RELS) is used for online estimation of the ESR and capacitance of the supercapacitor bank. Based on a residual signal which is defined as the difference between the voltages of the supercapacitor bank and RELS algorithm, the abnormal conditions of the supercapacitor bank are distinguished. Experimental results are presented to confirm the feasibility and precision of the proposed method. [ABSTRACT FROM AUTHOR]

In recent years, electric mobility is becoming a growing reality because of the increase of the oil demand and cost as well as the environmental effect of the conventional internal combustion engines. Since about a decade, in the USA, a public–private cooperative research initiative, called FreedomCAR (US Drive by mid 2012) has been working for developing high efficiency and cost competitive technologies for the electrification of private transport. This research presents the design and the comparison of two high performance, radial magnetisation, interior permanent magnets and synchronous motors, according to the FreedomCAR targets, equipped with different rotor shape geometries. The first is characterised by a non‐uniform airgap, whereas the second presents a conventional rotor shape. Both the machines are equipped with the same stator and a fractional slot concentrated winding. This paper highlights the benefits for using a non‐uniform airgap rotor design, especially concerning the efficiency, that represents the most difficult target to be satisfied. [ABSTRACT FROM AUTHOR]

A multidoped spinel, LiCoxNiyMn2−x−yO4 (x=y=0.1), that is of interest as a cathode material for rechargeable lithium batteries has been synthesized by the sol–gel method and characterized by X-ray diffraction (XRD) and electrochemical methods. Electrochemical experiments show that compared with Ni-doped spinel, Co-doped spinel delivers higher initial capacity, but its rate capability is poor. It is interesting to note that the initial capacity is enhanced, significantly when Co is doped into the Ni-doped spinel LiMn2O4, while the rate capability is retained. In other words, the multidoped spinel, LiCoxNiyMn2−x−yO4 shows the best features of the single-doped spinels, LiCoxMn2−xO4 and LiNiyMn2−yO4. Voltage versus capacity studies indicate that the phase transitions are reduced significantly for the multidoped spinel, LiCoxNiyMn2−x−yO4, during charging and discharging. X-ray diffraction data reveal that the diffraction peak intensity ratio of the typical peaks for the cubic phase (3 1 1) and (4 0 0), does not change after charging for the multidoped spinel, LiCoxNiyMn2−x−yO4. This suggests that cation disordering is completely prevented in this multidoped spinel material. [Copyright &y& Elsevier]

• Time and frequency domain tests are performed for a commercial Li-ion battery pack. • Different RC networks have been used to modeling the battery pack. • A Genetic Algorithm is applied to optimize the parameters of the battery model. • A hardware-in-the-loop simulations platform reproduces real driving cycles of an electric vehicle. • A low-order model reproduces with high accuracy the behavior of the battery pack. This article presents the optimization procedure based on genetics algorithms (GA) to obtain an equivalent electric circuit model (EECM) of a Li-ion battery pack. In the first part, a series of experimental tests in time and frequency domains were carried out. These tests were used to identify the parameters of the EECM under different State-of-Charge (SoC) for a commercial battery-pack. Each EECM consists of a voltage source connected in series with a resistor and a set of k networks composed of a resistor in parallel with a capacitor, where k = 1, 2 o 3 (1RC, 2RC, and 3RC). Subsequently, parametric identification of the EECM was performed using optimization techniques. At this stage, the topology that gives the lowest estimation error was determined, where the options analyzed were to use 1RC, 2RC, or 3RC networks. The objective function consists of minimizing the mean square error between measured and calculated impedances of the different proposed circuit models. GA was used to solve this optimization problem. The minimum error obtained was 1.07% and 1.05% for the EECM with 2RC and 3RC networks, respectively. Finally, these EECMs were implemented in Matlab®/Simulink to validate the Li-ion battery-pack model response for an electric vehicle application. A hardware-in-the-loop (HIL) simulation platform was developed to simulate the performance of an electric vehicle (EV) under different driving cycles. The results show that the GA-based approach allows obtained an EECM of low order to represent the highly dynamic behavior of a Li-ion battery with high accuracy. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new soft‐switching non‐isolated bidirectional converter (BDC) for the energy storage systems in DC traction. For this proposed converter, the soft commutation is achieved by turning on the main power switches with the help of auxiliary active switches, the inductor, the capacitor, and diodes. The basic operation of the converter is characterized as two operating types: boost and buck. The switching devices obtained zero voltage transition (ZVT) in both operating types, but the major advantage of this topology is achieved by reducing turn‐on losses with improved efficiency and minimizing reverse recovery time of IGBTs' anti‐parallel diodes. This paper mainly describes the principles of operation, design analysis, simulation, and implementation of DC‐DC converter of laboratory prototype with 150 V/250 V system under 1‐kW output power. [ABSTRACT FROM AUTHOR]