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Variable leakage flux (VLF) interior permanent-magnet synchronous machines (IPMSMs), which use intentional magnet leakage flux paths cross-coupled with the q-axis flux paths to reduce losses over driving cycles, have been introduced recently, but self-sensing has not been discussed for these machines. This paper focuses on the saliency angular offset attributes that are the primary metric for the well-established injection-based self-sensing methods. This paper begins by evaluating the effect of the intentionally designed cross-coupling in the VLF-IPMSM with rotor surface bridges on the saliency angular offset. This paper then proposes alternate rotor designs with side-loop structure that cause relatively linear and well-behaved cross-coupling that improves the load-dependent saliency angular offset characteristics. The effect of VLF properties on power conversion and driving cycle loss reduction capability is evaluated for the proposed designs. This paper also applies the concept of VLF design to conventional flux-weakening interior permanent-magnet machine rotor design and presents the loss reduction capability of such designs. [ABSTRACT FROM AUTHOR]

This paper presents the design and performance details of the Chevrolet Volt electric propulsion system. The propulsion system has two machines: One machine is operating mostly as a motor while the other machine is operating mostly as a generator. Both machines of the Volt electric drive system are permanent-magnet ac synchronous machine types with the magnets buried inside the rotor. The motor has distributed windings. However, as opposed to a conventional stranded winding, the Chevrolet Volt motor has bar-wound construction to improve the motor performance, particularly in the low to medium speed range. At higher speed, the skin and proximity effects in the stator bars lead to increased stator winding losses but are addressed in the design. The bar-wound construction also has excellent thermal performance, in both the steady-state and transient conditions, necessary for full electric vehicle (EV) driving. The generator uses concentrated windings. The concentrated winding construction has good slot fill and short end-turn length. These features resulted in good performance in the intended operational region and were an enabler for machine packaging inside the transmission. Both the machines exhibit excellent efficiency and exceptionally smooth and quiet operation. The machine design and construction details, as well as the measured thermal, electromagnetic, and acoustic noise performances, are presented in this paper. [ABSTRACT FROM AUTHOR]

Fractional-slot concentrated-winding (FSCW) interior permanent magnet synchronous motors (IPMSMs) have been attracting considerable attention due to their high power density, high efficiency, short end winding, high slot fill factor, low cogging torque, excellent flux-weakening, and fault tolerance capability. However, compared to integral-slot distributed-winding (ISDW) IPMSMs, the key challenge of using FSCW configurations is the significant rotor losses, particularly at high speed. To figure out the IPMSM with which winding configuration is more suitable for electric vehicle (EV) application, the thermal behaviors of four IPMSMs with ISDW, single-, double-, and four-layer FSCWs are comprehensively and comparatively investigated in this paper. First, electromagnetic design and loss analysis of the four IPMSMs are investigated to meet the EV traction motor requirements. Second, finite-element method is employed to investigate the thermal performance of the IPMSMs under different rotational speeds and torque overload capacities. Thirdly, experiments implemented on an ISDW prototype are carried out to validate the presented analysis method. Finally, some conclusions are drawn for a suitable winding configuration selection and the PM traction motor design. [ABSTRACT FROM AUTHOR]

A drive train system (DTS) powered by an ideal voltage source and driving a permanent-magnet synchronous motor (PMSM) is discussed in this paper. A two-level three-phase voltage source inverter is used as a means of power conditioning. This converter is not equipped with any harmonic filters on neither the ac nor the dc side. The mechanical part of the DTS is modeled as a double oscillator according to a drive train in an electric vehicle (EV). Various inverter modulation schemes are applied, namely, a single-phase hysteresis scheme, two-space vector-based hysteresis control schemes, for one, a stator aligned hysteresis and for another, a rotor aligned hysteresis, a modulation scheme based on pulsewidth modulation (PWM), such as sinusoidal modulation (including zero-sequence components) and space-vector pulsewidth modulation (SVPWM). The hysteresis-based pulsing methods are nondeterministic and build a current controller in their structure by nature. The other pulsing methods are deterministic due to their underlying PWM and require a separate control unit. The influence of these modulation schemes on the performance of the DTS is determined by assessing the level of inverter generated harmonics flowing to the PMSM and to the tires [downforce, (mechanical part)] as well as the resulting switching frequency (electrical part). The simulated results presented in the paper indicate that the pulsing frequency can be reduced by means of the hysteresis controller. In addition, the dispersion of the harmonic energy of the inverter generated spectrum partly compensate the absence of filters. [ABSTRACT FROM PUBLISHER]

This paper investigates a method to increase fuel economy of motors for an electric vehicle (EV) traction system. The low-torque region of an EV motor is frequently used in everyday urban driving and in fuel economy measurement. Pulsewidth modulation (PWM) carrier harmonic iron loss accounts for a high percentage of total loss for EV motors in this region. This paper reveals the relationship between phase current and carrier harmonic iron loss for a permanent-magnet synchronous motor (PMSM) in the low-torque region. Thus, a novel carrier harmonic loss reduction technique is proposed and applied to two sets of three-phase windings for a concentrated winding PMSM. The loss is successfully reduced in a 70-kW EV motor as well as a two-dimensional finite-element method (2-D-FEM) calculation. The efficiency of the developed motor is calculated and compared with that of a conventional motor in the JC08 mode driving cycle. [ABSTRACT FROM PUBLISHER]

This paper presents a combinational-logic-based approach for identifying faults that could occur in the drivetrain of an electric vehicle (EV). A real-time simulation model of an EV is used to study the behavior of available sensor signals and control commands, with specific measured quantities, during vehicle operation. Those quantities could be, but are not limited to, mean values of the phase currents, DC bus current, traction motor speed (if available), in addition to control command quantities. Focus is given to these quantities which are abundant in vehicle inverters and controllers for no added sensing costs. Those quantities carry information of offsets and disturbances that could occur under faulty operating conditions compared to nominal operation, and are thus observed and studied under these conditions. Using such information, a method is developed using simple combinational logic and thresholds to diagnose a fault occurring at any time during a vehicle drive cycle. By combining features of measured quantities that behave similarly irrespective of when the fault occurs during a driving cycle, the proposed method is fault-time-insensitive. The proposed method is presented and validated by real-time simulations to capture over 20 different faults injected at different drive cycle times and in different drivetrain components—electric machine, inverter, transmission, and sensors. Results show that the proposed method is able to robustly and successfully diagnose different faults irrespective of when would they occur. [ABSTRACT FROM AUTHOR]

A mobile charging system (MCS) for electric vehicles (EVs) is presented in this paper. The proposed MCS has a 2-MWh energy storage capacity for charging five EVs simultaneously with 75-kW individual charging rates. The MCS would be rechargeable from the available power substations (three phase, 480 V) with 375-kW charging rate. The appropriate modular power interface is designed and implemented between the MCS, batteries of the EVs, and the power substations. Experimental validation is presented in this paper to demonstrate the system performance and effectiveness under rapid charging requirements. [ABSTRACT FROM AUTHOR]

A switched reluctance motor (SRM) is one of the candidates of rare-earth-free motors for hybrid electric vehicles (HEVs). An SRM has been developed with same interior permanent magnet synchronous motor (IPMSM) dimensions having competitive maximum torque, operating area, and maximum efficiency. However, this SRM has a windage loss of 1.3 kW due to the salient poles of the SRM driven at the maximum rotational speed. In addition, considerable acoustic noise is caused by the salient poles. In this paper, a simple design of a cylindrical outer shape rotor is proposed, and a comparison with the conventional SRM rotor is carried out. It is found that the efficiency is improved due to the windage loss reduction. It is also found that the acoustic noise is significantly reduced in the proposed rotor design. [ABSTRACT FROM AUTHOR]

The coordinated development of charging points reveals to be crucial in supporting the envisaged diffusion of electric vehicles, along with their proper design to ensure smart and fast charging performances and economic advantages for drivers. The integration of charging points with local generation and storage can enhance this process. In this paper, the structure of a modular electric vehicle supply infrastructure is proposed. It is based on the integration of photovoltaic rooftops, energy storage and electric vehicle stations in a dc microgrid, enabling coordination and control as well as the functions of bidirectional charging and the possibility to provide grid services at connection point. The main features of the technical demonstrator are described, along with the targeted innovations for system manager and final user, and the possible control functions involving operation planning, real-time control, and ancillary service market inclusion. [ABSTRACT FROM AUTHOR]

Load power sensitivity to voltage changes continuously in the distribution grid due to the increased variability of the load demand (e.g., electric vehicles charging) and generation production (e.g., photovoltaic). Classical sensitivity identification methods do not respect the fast dynamics of such changes: they require long data history and/or high computational power to update the load sensitivity. The proposed online load sensitivity identification (OLLI) approach is able to identify the load sensitivity in real time (e.g., every minute). This paper demonstrates that the OLLI can be achieved not only with the advanced smart transformer metering system but also with commercial industrial metering products. It is shown that OLLI is able to identify correctly the load sensitivity also in the presence of noise or fast stochastic variation of power consumption. The industrial metering-based OLLI application has been proven by means of a power-hardware-in-loop evaluation applied on an experimental microgrid. [ABSTRACT FROM AUTHOR]

There is significant interest in the development of switched reluctance machines (SRMs) for use in automotive traction applications. This has been driven by their low cost compared with rare earth permanent-magnet-based motors, driven by the high cost of rare earth permanent magnets, coupled with their potential for competitive torque densities. This paper describes the development of a variant of the SRM, utilizing a segmental rotor construction, which has previously been demonstrated to provide the potential for significant improvement in torque densities compared with SRMs with a conventional toothed rotor construction. This paper describes a strategy that has been developed to optimize the Segmental Rotor SRM to maximize efficiency with the aim of achieving performance equivalent to that of the 80-kW interior permanent-magnet machine utilized in Nissan's LEAF electric vehicle. Optimization applies a combination of static and dynamic analyses in order to achieve a full and computationally efficient assessment of motor performance across different regions of the torque speed envelope. Test results from a prototype motor are also presented. [ABSTRACT FROM PUBLISHER]

Since the mass and volume of electric machines are heavily dependent on their thermal constraints, it is important to find ways to analyze and simultaneously optimize their electromagnetic (EM) and thermal performances. This paper presents an approach for coupling the finite-element EM and thermal analyses of electrical machines using temperature-dependent material properties, so that temperatures inside a candidate machine can be predicted simultaneously with its EM performance. In addition to steady-state conditions, the coupled analysis has been extended in this paper to transient operation for machines that are required to deliver high torque/power for short intervals. Three 30-kW 10-pole 12-slot surface permanent magnet machines optimized for maximum torque density, minimum cost, and maximum efficiency, respectively, have been investigated. This coupled EM–thermal analysis makes it easier for designers to maximize the winding current density to achieve the highest possible torque/power ratings within thermal limits set by the winding insulation or demagnetization limits. [ABSTRACT FROM PUBLISHER]

The continuous increase of electric vehicles (EVs) is expected to introduce several challenges to power systems among which is the deteriorating reliability of power supply. This paper proposes two adequacy metrics to quantify the maximum permissible EV loads for a power system without deteriorating its reliability and the required improvements to power systems to accommodate high penetrations of EVs, which are defined as follows: 1) extra effective available energy for EVs’ charging (EEAE-EVs) and 2) extra effective required generation to accommodate EVs (EERG-EVs). The EEAE-EVs provides a measure for the maximum amount of EV loads that a power system can accommodate without adding new generation while maintaining its reliability. The EERG-EVs provides a measure to the minimum amount of new generation that is needed to restore the reliability level of a power system if the load of EVs exceeds the maximum permissible load of the system. These metrics provide a decision aid to power system planners and operators on when and how to perform generation expansion. The importance of the proposed metrics is demonstrated on the IEEE Reliability Test System (IEEE RTS) with real EV charging data. The sequential Monte Carlo simulation method is used in evaluating the well known power system reliability indices, the EEAE-EVs, and the EERG-EVs. The results show that a power system can accommodate EV loads without deteriorating its reliability as long as EV loads do not exceed the EEAE-EVs of the system. For the IEEE RTS, the EERG-EVs shows that the amount of the required generation to maintain system reliability is about half of the added EV loads from 330–660 MW. [ABSTRACT FROM AUTHOR]

In this paper, the intermittent control is proposed for switched reluctance machine (SRM) drive to both increase the efficiency and decrease the cost of the traction system for low-cost electric vehicles. With the purpose of maintaining the average machine torque required by the load, the intermittent control imposes a higher phase torque during a shorter time. The simulation and experimental results achieved with three different SRMs show that the intermittent control increases the system efficiency by reducing the converter losses and the core losses. Additionally, three different strategies of the control have been proposed to analyze their impact automotive application based on the criteria of efficiency, machine vibration, and torque pulsation. It can also be easily applied for any SRMs using average-torque-control-based methods. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are recently gaining traction in the power sector due to various challenges and opportunities they provide to utility operators. For electric utilities that incorporate demand side management (DSM) programs, EVs could become either a burden or an advantage depending on their charging control strategy and the signaling of the DSM program. This paper proposes a decentralized fuzzy-based controller to successfully integrate and coordinate the charging of EVs that ensures fair charging of EVs at different point of connections (POCs) in the distribution grid where voltage conditions might not be the same. The controller operates in an autonomous mode that reduces the monetary cost of the communication overhead and preserves bandwidth. The proposed controller takes into consideration the owner requirements in terms of energy needed and time to charge, the voltage at the POC with the grid, and the pricing signal coming from the utility. The controller is tested under different DSM programs that exist in the literature. This paper also proposes a new DSM program that is capable of benefiting from EVs as prosumers that can provide grid services. The controller's performance was validated through MATLAB simulations that showed the controller's ability to successfully coordinate the charging of EVs in a fair manner and achieve flat system peaks without any rebound effect. The controller was also successfully tested in the presence of voltage control units, such as capacitor banks, and in the presence of distributed generations. [ABSTRACT FROM AUTHOR]

This paper presents the performances of a surface-mounted permanent-magnet synchronous machine (SM-PMSM) from the electromagnetic and structural analysis point of view, which are evaluated numerically and through tests. The goal is to evaluate the possibility to use this SM-PMSM for the propulsion of a light-electric vehicle (L-EV), knowing that on one hand it has the best power density and, on the other hand, a torque wave with high ripples induces vibration and noise. This paper discusses the limits and the advantages for such a propulsion solution in order to evaluate its suitability for the L-EV applications. [ABSTRACT FROM PUBLISHER]

This paper proposes a new position sensorless control for interior permanent-magnet synchronous motor (IPMSM) drives fed by overmodulation mode pulsewidth modulation (PWM) voltage source inverter. It is attractive to expand the speed range of the IPMSM for application to electric vehicles, electrical household appliances, and so on. An overmodulation mode PWM voltage-source inverter makes it possible to solve problems such as efficiency, wide speed range operation, and so on. Most position sensorless controls based on inverter output voltage knowledge, however, cannot directly be utilized because the voltage reference obtained by the controller is not equal to the inverter output voltage. This paper proposes unknown input observer to estimate rotor position without voltage knowledge, and investigates robustness to inductance variation. [ABSTRACT FROM AUTHOR]

The paper discusses the development status of the inductive power transmission for automotive applications. This technology is, in fact, gaining the interest of electric vehicle manufacturers as an effective strategy to improve the market penetration of electric mobility. Starting from the origin of this technology, the paper presents an overview of the current state of the art as well as the current research and industrial projects. Particular attention is devoted to the description of a prototypal system for the dynamic inductive power transmission whose goal is to extend the battery range by a fast partial recharging during the movement of the vehicle. [ABSTRACT FROM AUTHOR]

While interior permanent magnet (IPM) machines have been considered state of the art for traction motors, synchronous reluctance (SynRel) motors with advanced materials can provide a competitive alternative. IPM machines typically utilize neodymium iron boron permanent magnets, which pose an issue in terms of price, sustainability, demagnetization at higher operating temperatures, and uncontrolled generation. On the other hand, SynRel machines do not contain any magnets and are free from these issues. However, the absence of magnets as well as the presence of bridges and centerposts limit the flux-weakening capability of a SynRel machine, and limit the achievable constant power speed ratio without having to significantly oversize the machine and/or the power converter. In this paper, a new material referred to as the dual-phase magnetic material, where nonmagnetic regions can be selectively introduced within each lamination, will be evaluated for SynRel designs. The dual-phase feature of this material enables nonmagnetic bridges and posts, eliminating one of the key limitations of the SynRel designs in terms of torque density and flux weakening. This paper will present the design, analysis, and test results of an advanced proof-of-concept SynRel design utilizing dual-phase material with traction applications as the ultimate target application. [ABSTRACT FROM PUBLISHER]

Electric vehicles (EVs) and their application raise new questions and demands. Accordingly, the charging process of EVs is a novelty in everyday life when using such vehicles. This paper presents results of user charging behavior within a field test. In the field test, 500 people with above average yearly mileage took part in integrating the vehicles into their everyday lives. For the results of this paper, the charging behavior of 200 test people is taken into account. The differences in user behavior between battery electric vehicles (BEVs) and extended range electric vehicles (EREVs) are discussed. The results indicate that there are various opportunities for grid services based on EVs, as the vehicles are connected or parked close to a charging station the majority of the time. Moreover, the results also show deviating user behavior for the BEVs and EREVs. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid excitation synchronous machine (HESM) with magnetic shunting rotor is designed for electric vehicle traction applications with consideration of electromagnetic performance and mechanical strength. The HESM with magnetic shunting rotor is a topology of brushless HESM with extended magnetic bridge to embed field windings. The rotor core extends along the axial direction and the increase of rotor length is inevitable, which reduces torque density. In order to improve torque density, the excitation structure is optimized by built-in field windings and the HESM with one-end built-in field windings is presented. To improve the flux regulation capability and decrease the magnet consumption further, the HESM with dual-end built-in field windings is proposed and investigated. The comparative study of the performances of the original HESM and the HESMs with one/dual-end built-in field windings is carried out by three-dimensional finite element method (FEM). An original HESM prototype and a permanent magnet synchronous machine prototype have been developed and the experimental results, which agree well with the FE-predicted results, confirm the advantages of HESM and the validity of FEM used in predictions in this paper. [ABSTRACT FROM PUBLISHER]

This paper presents the performance analysis and comparison of two types of bidirectional dc–dc converters—cascaded buck–boost capacitor in the middle and cascaded buck–boost inductor in the middle for use in plug-in electric and hybrid electric vehicles. The comparison of the two converters is based on device requirements, rating of switches and components, control strategy, and performance. Each of the converter topologies has some advantages over the other in certain aspects. Efficiency analysis has been carried out for specific scenarios in vehicle applications. The simulation and experimental results are provided for both converter types. [ABSTRACT FROM PUBLISHER]

This paper mainly studies the effect of the winding layer number on the performance of interior permanent-magnet (IPM) synchronous machines equipped with fractional-slot concentrated windings (FSCWs) for electric vehicle applications. In order to quantitatively evaluate FSCW-IPM machines with different numbers of winding layers, three models with single-, double-, and four-layer winding configurations have been built to compare back electromagnetic force, average torque, torque ripple, core losses, copper losses, flux-weakening capability, overload capability, etc. Both theoretical and finite-element analysis results illustrate that multilayer windings yield lower $d$-axis inductance and weaker flux-weakening capability but better overload capability. It is also shown that torque ripple and core losses are significantly reduced in machines with multilayer windings. [ABSTRACT FROM AUTHOR]

This paper presents the physical construction and test results of two new demonstrators of a motor integrated permanent magnet gear (MIPMG), which is a second version of an already tested demonstrator. The demonstrators will be used as traction units for a battery electrical vehicle and the background for the specifications are elaborated. Simulated and measured results of rotational losses of the first and second versions are compared. The efficiency of the new design is investigated and compared with three direct-drive motors in a few operating points, and the MIPMG v.2 seems superior when used as a traction unit in urban traffic. [ABSTRACT FROM PUBLISHER]

This paper studies the characteristics of battery packs with parallel-connected lithium-ion battery (LiB) cells. To investigate the influence of the cell inconsistency problem in parallel-connected cells, a group of different degraded LiB cells were selected to build various battery packs and test them using a battery test bench. The physical model was developed to simulate the operation of the parallel-connected packs. The experimental results and simulation indicate that, with different degraded cells in parallel, there could be capacity loss and large difference in discharge current, which may cause further accelerated degradation and a more serious inconsistency problem. [ABSTRACT FROM PUBLISHER]

This paper investigates the need of coordinated operation of conservation voltage reduction (CVR) in the presence of electric vehicle (EV) penetration in the active distribution network. In order to analyze the impact of both the technologies (CVR and EV), a time horizon-based model predictive Volt/VAR optimization (VVO) methodology has been introduced in smart grid framework. The proposed VVO methodology operates in centralized as well as local controls under different time scale of operation, including cloud transient effects on solar photovoltaic (PV) power output. Moreover, the control algorithms also consider the uncertainties in load demand and PV power generation. The VVO methodology has been validated with and without presence of EV loads in the distribution network. The VVO includes the impact of different EV charging loads having the ability of participation in reactive power support at selected charging points. This is also referred to as vehicle-to-grid operation in terms of reactive power dispatch only. Besides, the voltage and VAR regulation through smart inverters of PVs and EV charging station has been fruitfully utilized in global as well as local domain. A real-time Volt/VAR droop based controller has been introduced to control the smart inverters reactive power dispatch. To validate the developed methodology, a real-time cosimulation framework, using real-time digital simulator and Python interface, has been built. The proposed model predictive VVO algorithm has been tested and validated on a modified IEEE 34 bus test system. The simulated results reveal that significant CVR energy savings and losses reduction has been achieved without violating the system constraints. The voltage control algorithm works well in both slow and fast time scales. [ABSTRACT FROM AUTHOR]

The recently approved regulation about self-consumption in Spain will dramatically change the level of penetration of photovoltaic distributed generation combined with storage devices at residential level in short term. In this paper, we will study the impact of the massive installation of such technologies under the constraints imposed by the new regulation, over the terminal distribution network. As it will be demonstrated, this impact will be drastic in terms of energy demand, voltage profile, and load curves. [ABSTRACT FROM AUTHOR]

This paper describes a new design technique for electric-vehicle traction machines in order to achieve high efficiency against a defined driving cycle such as the New European Drive Cycle, while satisfying the required torque–speed operating range and other volumetric and thermal design constraints. This paper is undertaken as a part of the Personal Mobility Project funded by the European Union. By analyzing the energy distribution of a given driving cycle, the energy efficiency of the traction machine over the driving cycle can be characterized against a number of representative points, and the design optimization can be carried out with respect to these points. This dramatically reduces the computation time of the design optimization process, while improving the energy efficiency of the traction machines. The utility of the design technique has been illustrated through design case studies and its effectiveness validated by experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a voltage-limited finite-settling-step direct torque and flux control (FSS-DTFC) method with a constant switching frequency for torque-controlled interior permanent-magnet synchronous motors (IPMSMs). The proposed control law dynamically scales the voltage vectors on the hexagonal voltage boundary to ensure the maximum torque capabilities under the given operating conditions while simultaneously regulating the stator flux linkage magnitude under flux-weakening operation. Instead of relying on classical overmodulation methods at voltage limits, this paper developed two independent voltage truncation rules to facilitate the possible voltage vector choices. The analytical solution led to the dynamic voltage modification at each time step with respect to the available inverter voltage. The voltage-limited FSS-DTFC approach has potential advantages in achieving a fast transient torque trajectory and direct manipulation of the stator flux linkage while exploiting the maximum voltage excitation. [ABSTRACT FROM AUTHOR]

This paper discusses the development of new winding configuration for six-phase permanent-magnet (PM) machines with 18 slots and 8 poles, which eliminates and/or reduces undesirable space harmonics in the stator magnetomotive force. The proposed configuration improves power/torque density and efficiency with a reduction in eddy-current losses in the rotor permanent magnets and copper losses in end windings. To improve drive train availability for applications in electric vehicles (EVs), this paper proposes the design of a six-phase PM machine as two independent three-phase windings. A number of possible phase shifts between two sets of three-phase windings due to their slot–pole combination and winding configuration are investigated, and the optimum phase shift is selected by analyzing the harmonic distributions and their effect on machine performance, including the rotor eddy-current losses. The machine design is optimized for a given set of specifications for EVs, under electrical, thermal and volumetric constraints, and demonstrated by the experimental measurements on a prototype machine. [ABSTRACT FROM AUTHOR]

Future applications of wireless power transfer will include powering various devices in a room, charging electric vehicles in a parking area, charging moving robots, and so on. Therefore, practical wireless power transfer must be able to support complicated configurations, for example, combination of multireceiver and repeaters. Many past works have discussed methods for improving efficiency and, more recently, extended the methods to multireceiver systems. However, controllable power division among receivers is also an important feature as receivers nearer to the transmitter tend to absorb more power compared to further ones. In this paper, a new impedance matching and power division method utilizing impedance inverters only at the receiver sides is proposed. The mathematical equations in the proposed method are then generalized for arbitrary number of receivers and arbitrary number of repeaters. [ABSTRACT FROM PUBLISHER]

To minimize the ripple on the dc-link current and torque due to carrier signal injections, conventional saliency based self-sensing control schemes using voltage and current carrier signals for interior permanent magnet synchronous machines (IPMSMs) are optimized in this paper. Carrier signal oriented coordinates are introduced to model the high-frequency behavior of IPMSMs and are used for the analysis and signal processing of proposed methods. Moreover, stability issues are discussed in this paper. Experimental results on a commercial high voltage inverter for application in hybrid and electrical vehicles confirm the applicability of the proposed methods. [ABSTRACT FROM AUTHOR]

High reliability and wide range of speed regulation are key factors for motor drive system in electric vehicles (EVs). To meet the requirement for EV application, this paper proposes and investigates a new five-phase brushless fault-tolerant hybrid-excitation motor. This motor has several advantages over the conventional permanent magnet (PM) motor, such as high fault tolerance and adjustable flux. In addition, to realize flux regulation, based on the utilization of the high-harmonic component of the stator magnetic motive force (MMF), the rotor field winding and the rotor harmonic winding are designed. Unlike the existing hybrid-excitation machines with rotor PM, the proposed motor can achieve the balance between simple structure and no sliding contacts. Moreover, the topology and operation principle of the proposed motor are analyzed. Also, the characteristics of the proposed motor are investigated by using finite-element analysis and experiments with a 2 kW prototype machine. The experimental results are given to be consistent with the theoretical analysis, which validates the correctness of the theory. [ABSTRACT FROM AUTHOR]

In this paper, the zero sequence circulating current in open winding permanent magnet synchronous machine (OW-PMSM) drives with common dc bus is systematically analyzed for the first time. It is revealed that the zero sequence circulating current is affected by zero sequence back-electromotive force, cross coupling voltages in zero sequence from the machine side, pulse-width modulation induced zero sequence voltage, and inverter nonlinearity from the inverter side. Particularly, the influences from the cross coupling voltages in zero sequence and parasitic effect of inverter nonlinearity are investigated for the first time in this paper. Then, the synthetic model of the equivalent zero sequence circuit is proposed as well. Each cause is studied independently via analytical modeling, finite element analysis, and experiments. Meanwhile, to tackle this issue, the relevant suppression strategy using frequency adaptive proportional resonant controller is presented and tested on the 3 kW OW-PMSM platform. [ABSTRACT FROM AUTHOR]

This paper is focused on the reliability evaluation of an electric vehicle (EV) motor based on hairpin technology. Besides bearings (not discussed here), the weak point of an electric motor is its insulating system. For inverter-fed motors, the inception of partial discharges might lead to failure in a matter of days, and thus, deserves particular attention. Qualification and lifetime evaluation of inverter-fed machines are described in IEC 60034-18-41, which specifies accelerated aging procedures and considers partial discharge inception as the end-of-life criterion. This standard was used as a reference for this paper. The only exception is that insulation models were subjected to the mechanical stress profile reported in the ISO 16750-3-2012 standard since an automotive motor is subject to significant vibrations during its operation. From the tests performed, we observed that, with the hairpin technology, turn-to-turn is the weakest link in the insulation system. All the insulation models were partial discharge (PD) free from the beginning of the tests to breakdown and the root cause for breakdown was, in all cases, traced back to cracks on the surface of the insulation. This suggests that, depending on insulating enamel thickness and conductor geometry, some insulation systems are intrinsically PD free by design, despite the effect of aging. Considering the severe vibration profiles typical of EVs, and the principal breakdown mechanism (cracking of the insulation), mechanical stress coupled with thermal stress appears as the main aging driver. Therefore, this paper spotlights the lack of proper standards for the qualification of automotive electric motors and hints at the possibility that IEC 60034-18-41 considers dealing with motors that might be intrinsically partial discharge free even after long-term exposure to operational stresses. [ABSTRACT FROM PUBLISHER]

This paper proposes a state-of-the-art algorithm for a real-time charging recommendation for an electric vehicle driver based on an accurate real-time range indicator system to avoid range anxiety. The charging recommendation algorithm alerts the driver when charging is deemed required for the selected route. This algorithm determines the nearest charging location obtained using GPS based on an accurate estimation of state of charge (SoC) at the destination and when charging determines the optimum charging time required by the battery to have sufficient energy to reach the destination. The graphical user interface of the real-time range indicator system is also used to show the driver an accurate estimation of the remaining range to destination and the current SoC. The results from simulations of a range of routes validate the proposed algorithm. [ABSTRACT FROM AUTHOR]

A fully decentralized controlled (FDC) electric vehicle (EV) charger, where its design is intended to mitigate the charging impact on power grids, is proposed in this paper. The proposed FDC EV charger uses the parameters measured from the power grid, EV charger and EV battery pack to adjust the charging current. Fuzzy logic control is used in this paper to integrate these measured parameters into the proposed FDC EV charger. As the proposed charger can be realized without a centralized control center and information exchanges between EV chargers, an FDC scheme for EV charger can therefore be effectively achieved. A prototype of the proposed FDC EV charger with a rated power of 500 W is implemented. Experimental results verify that the proposed charger can automatically adjust the charging current according to variations in the power grid and EV. Simulations analyze the impact of 100 EVs with a rated power of 7 kW charged simultaneously. Simulation results show that the EV charging impact on power grids can be effectively mitigated by the proposed FDC EV chargers. [ABSTRACT FROM PUBLISHER]

This paper presents a control strategy study of a dual-wheel drive electric bicycle by taking the human–bicycle coupling into consideration. Containing two electric motors (one on the hub of each wheel), the bicycle is controlled by a fuzzy controller, which ensures a sharing of the total power between the front and rear motors. The goal of this paper is to develop a control method for an electric bicycle with regenerative braking and dual-wheel drive. The proposed method can achieve a better user experience (response time and speed control) than the one currently proposed to the market. The two motors are controlled by two separate torque references and the control algorithm is carefully designed in order to consider the coupling between human reaction time and motor driving response time. In addition, both wheels are equipped with kinetic energy recovering breaks allowing an increased autonomy. The developed controller also has the ability to adapt different road conditions, in the objective of user experience improvement and power saving. [ABSTRACT FROM PUBLISHER]

This paper presents the stability analysis of dc distributed power systems with multiple converter-controlled loads. The load converters are tightly controlled, behaving as constant power loads with low-damped $LC\;$ filters. The dynamic behavior of the system in high frequency range is often not studied with the classical tools based on conventional averaging techniques. However, dc power systems with the reduced size filter, and consequently, the high resonant frequency, are widely used in transportation applications. In this paper, the stability analysis of the system is established based on a discrete-time model of the system, taking into account the switching frequency and intrinsic nonlinearities of the system model. The impacts of the filter parameters and interactions among the constant power loads are investigated with the proposed discrete-time method. Moreover, an active stabilizer is developed and included in the dynamic model of the system, in order to extend the stability margin. The theoretical observations are then validated experimentally on a laboratory hardware prototype. [ABSTRACT FROM AUTHOR]

In this paper, comparison between simulation and experimental testing of an electric hybrid telehandler vehicle is presented. A new hybridization factor for working vehicles is introduced, taking into account driving and loading power, to classify the hybrid architecture choices. The research is inserted in the frame of a cooperation project between Politecnico di Italy, and Merlo SPA, Italy, main Italian telehandler producer. The numerical model built in MATLAB/SIMULINK is used to simulate the performance level of the vehicle in different working conditions in order to study a typical telehandler cycle. The comparison between experimental and simulated results shows a very good agreement in different operating conditions. Performance level of the electric hybrid vehicle satisfies the requirements and reaches the same level of a conventional telescopic machine, but with a remarkable reduction of energy and consequently fuel consumption. [ABSTRACT FROM AUTHOR]

An improved bridgeless (BL) Cuk converter-based electric vehicle (EV) battery charger with high power factor and increased efficiency is designed and developed in this paper. It provides low cost and high-power-density-based charging solution for the EV. This charger incorporates less number of devices operating over one switching cycle, which reduces the additional conduction loss incurred by a diode bridge rectifier of the conventional charger. Hence, it improves the charger's efficiency. The added advantage of the proposed topology is that the unwanted capacitive coupling loop is removed, as well as the unwanted conduction through the body diode of the inactive switch in the previously developed BL Cuk converter is avoided. This significantly improves the charger's efficiency. For the constant current and constant voltage charging, the commands are synchronized by a flyback converter. The proposed charger draws a sinusoidal current from ac mains and the total harmonic distortion in the supply current is reduced to the limits specified by the IEC 61000-3-2 guidelines. The improved efficiency and power quality indices of the proposed charger are investigated to demonstrate its satisfactory charging operation at all operating conditions. [ABSTRACT FROM AUTHOR]

This paper deals with the control and implementation of solar photovoltaic (PV) array-based multi-objective bi-directional charger beneficial for electric vehicle (EV), household load, and utility. For EV, the charger provides the charging facility. For household load, the charger acts as a standalone inverter, and for utility the charger acts as an active power filter. However, for providing the multi-functionality and the multi-mode operation capability of the charger, a reconfigurable control strategy is proposed. Moreover, an adaptive dc-link voltage strategy is proposed for achieving the optimum voltage at dc link under all voltage conditions for achieving minimum ripple in grid currents. The charger also uses a voltage synchronization strategy for achieving the seamless mode transition between the grid-connected and standalone modes. In grid-connected mode, the charger uses a double second-order generalized integrator-based positive sequence estimator along with the improved linear sinusoidal tracer-based algorithm for generating the balanced and sinusoidal reference grid currents, under the unbalanced and distorted grid voltages. The charger is implemented in the laboratory, and the performance is presented under various steady-state and dynamic conditions. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive solution that allows a wirelessly connected electric vehicle (EV) to be autonomously charged and discharged, during long-term parking and/or transient stops. A bilayer power flow controller for bidirectional wireless power transfer system (BWPTS) in EVs applications is proposed. The proposed controller can manage the power flow between the EV and surrounding infrastructures, such as utility grid, home micro-grid, building micro-grid, road, or another vehicle. It consists of two control layers; the first is responsible for communicating with the surrounding infrastructures and gathering information from the vehicle operator, charging station, utility grid, and battery management system. These data are analyzed to generate the reference power signal with information about the mode of operation (charge, discharge, or abstain) and rate. The second layer receives the reference signal and predicts the control parameters for the resonant converters (on both the vehicle and grid sides) to track the desired power. The proposed algorithm is adaptively estimating the mutual inductance to consider the misalignments in the system, based on a new simple real-time mutual estimation algorithm using a single voltage measurement from the vehicle side. The second control layer is designed based on an accurate analytical model for the BWPTS's power flow. For verification purposes, a prototype for BWPTS was built and driven by the proposed controller, which was implemented using a field-programmable gate array integrated circuit. Also, a vehicle-level simulation was performed to validate the operation of the proposed controller in quasi-dynamic wireless charging at traffic signals. The proposed controller shows fast and stable response during both the transient and steady-state operation in comparison with the conventional proportional-integral controller. [ABSTRACT FROM AUTHOR]

This paper proposes an interactive decision-making model for the operations of electric vehicles (EVs) and power grid, in the perspective of energy and reserve. In this model, EVs optimize their energy and reserve plans considering prices set by the power grid. Meanwhile, the power grid aims to obtain the optimal energy and reserve prices for EVs, in order to maximize its benefits. Afterward, we use the generalized Stackelberg game to formulate the interactive decision-making model, and prove the existence and uniqueness of the generalized Stackelberg equilibrium. Finally, simulation results verify that the proposed interactive model can well enhance benefits of EVs while guaranteeing their quality of charging services. [ABSTRACT FROM AUTHOR]

In this paper, we develop formulation of a multi-objective optimization problem (MOOP) to optimally size a battery unit (BU) ultracapacitor (UC) hybrid energy storage system (HESS) for plug-in electric vehicle (EV). In this application, the objectives were to minimize cost, weight, volume of the HESS simultaneously maximizing the remaining cycle life of the BU at the end of the driving cycle. The MOOP is solved by the non-dominated sorting genetic algorithm type 2 algorithm. Detailed mathematical models for the BU and UC are given. The thermal effect on performance and sizing are also included in the formulation. The power demand by the EV powertrain is shared amongst the BU and HESS by two methods: First is by using wavelet transformation, while the second is by using power split ratio. The ratio of the power (i.e., power split) handled by each storage unit was determined by the optimizer. A sensitivity analysis was conducted for the power splitting ratio verification. The problem was solved for using the urban dynamometer driving schedule and the highway fuel economy test driving profiles. This has resulted in sizing of an HESS with lower cost, volume, and weight than those existing in literature. Finally, the effect of changing the motor type on the MOOP result was investigated. [ABSTRACT FROM AUTHOR]

Switched reluctance machines (SRMs) are witnessing increased interests and applications in the industry and scientific communities thanks to the advantages of rigid structures, high reliability and robustness, the absence of permanent magnets, fast dynamic response, and low manufacturing cost. SRMs have become a feasible and popular alternative to conventional electric machines, such as induction machines and permanent magnet machines, with variable speed drives in many applications. Since improving the electromagnetic and thermal performances of an SRM at the design stage is of significant value, this paper presents an in-depth literature review on the status and potential trends of the technology pertinent to the design and optimization of SRMs in the following aspects: the mathematical modeling of the electromagnetic and thermal fields in SRMs, the enhancement of the performances in terms of the torque ripple, acoustic noise, efficiency, and torque density, and the multiobjective design optimization incorporating all the above factors. Finally, the presence of SRMs and their design considerations for specific applications in electric vehicles, aircraft and aerospace systems, wind generators, high speed, and energy storage systems are extensively discussed in this paper. The existing approaches advancing the SRM technologies are systematically and comprehensively summarized and compared for each category. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are characterized by having a very good performance in terms of efficiency, lifetime, and self-discharge, which allowed them to become the major player in the electric vehicle (EV) applications. However, they were not able to totally overcome the EV range anxiety. Thus, a research is carried out nowadays to develop batteries with even higher gravimetric energy density, which should allow a substantial range increase. One of the technologies, which should be able to meet the range requirements is the lithium–sulfur (Li–S) battery. Thanks to the extensive research and development efforts, these cells are close to enter the market, being evaluate in various projects. In this paper, we have proposed an electrical circuit model for a Li–S pouch cell, which was parameterized based on extensive electrochemical impedance spectroscopy measurements. The developed model was verified using static and pulse discharge profiles, showing a good accuracy in predicting the voltage of the tested Li–S battery cell. [ABSTRACT FROM AUTHOR]

The impact of GaN mosfet and the performance of three-phase traction inverter for electric vehicles are closely investigated in this paper. Two versions of inverter have been illustrated: first one with Si-IGBTs, whereas the second one is built with GaN-mosfets with similar rating of voltage and current. The loss model is expounded for both the inverters; thereafter total losses are calculated considering New European Driving Cycle profile along the speed and torque of the permanent magnet synchronous motors. Further, for close-loop operation of propulsion drive, predictive current controller is proposed and compared with conventional PI controller while to control the speed, only PI controller is used. Moreover, the losses of both types of inverters are compared and the compared result confirmed that the inverter built up with GaN-mosfets with proposed current controller increases the efficiency of the propulsion drive leads to enhancement in driving range of the vehicles. [ABSTRACT FROM AUTHOR]

In this paper, an integrated model for acoustic evaluation of electric vehicles is introduced. The paper focuses on the force excitation part of the model. The analysis is performed for permanent magnet synchronous machines. The excitation forces are placed on the stator teeth and calculated for a structure dynamic model of the power train. A model for the acoustic emission is adapted, and finally, the psychoacoustical behavior is characterized at the position of the driver of the e-car. An approach for the design of the rotor pole topology is introduced to ensure a beneficial acoustic behavior under consideration of air gap flux density and related force densities on the stator teeth. The calculation is performed using finite-element analysis simulation, but also analytical design methods are considered. Objective of this comparison is a very short computation time and, therefore, an efficient simulation process. The model is validated by measurements on test benches. [ABSTRACT FROM PUBLISHER]

Electric vehicles (EVs) provide a feasible solution to reduce greenhouse gas emissions and thus become a hot topic for research and development. Switched reluctance motors (SRMs) are one of the promised motors for EV applications. In order to extend the EVs’ driving miles, the use of photovoltaic (PV) panels on the vehicle helps to decrease the reliance on vehicle batteries. Based on the phase winding characteristics of SRMs, a tri-port converter is proposed in this paper to control the energy flow among the PV panel, battery, and SRM. Six operating modes are presented, four of which are developed for driving and two for standstill onboard charging. In the driving modes, the energy decoupling control for maximum power point tracking (MPPT) of the PV panel and speed control of the SRM are realized. In the standstill charging modes, a grid-connected charging topology is developed without a need for external hardware. When the PV panel directly charges the battery, a multisection charging control strategy is used to optimize energy utilization. Simulation results based on MATLAB/Simulink and experiments prove the effectiveness of the proposed tri-port converter, which have potential economic implications to improve the market acceptance of EVs. [ABSTRACT FROM PUBLISHER]