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This paper presents a novel active power control scheme for SRMs that are used as S/G units at MEAs; the proposed method uses a vector-controlled SAF, facilitating the acceleration of the SRM during starter mode and the efficient power control of the SRG at various operational points during generator mode. Moreover, an energy storage unit is incorporated in the SAF, aiming at enhancing the SRM's starting torque production and taking full advantage of the SRG's energy generation capability, through the appropriate phases’ magnetization regulation that is imposed by the developed adaptive SAF vector control. In addition, the proposed scheme provides enhanced FRTC during both modes of operation. The mathematical analysis is verified through MATLAB/Simulink simulations, while the performance of the S/G concept under study is evaluated via real-time CHIL tests, with the use of the dSPACE 1202 (MicroLabBox) platform and the 16-bit dsPIC30F4011 microcontroller. [ABSTRACT FROM AUTHOR]

This article studies the transmit beamforming security in the dual-functional radar-communication (DFRC) system, where the radar beam also serves as the artificial jamming to suppress potential eavesdropper channels. Unlike previous researches, which assumed that the lone target might be a potential eavesdropper on the adversary side, this paper analyses a more generic scenario in which the eavesdroppers’ channel state information (CSI) is unknown. The eavesdropping rate should be limited to guarantee transmission confidentiality, which is intractable owing to the unknown CSI. To address this issue, we present the long-term eavesdropping signal-to-interference-plus-noise ratio (SINR) as a more tractable security metric. Based on the long-term eavesdropping SINR, the sum rate maximization (SRM) and jamming power maximization (JPM) transmission scheme are investigated. For the SRM scheme, we propose a zero-forcing (ZF) suboptimal algorithm to solve the non-convex fractional programming (FP) problem, and for the JPM scheme, the resultant problem is solved via the semidefinite relaxation (SDR) technique. Finally, numerical results validate the effectiveness of the proposed beamforming approaches. [ABSTRACT FROM AUTHOR]

This paper proposes a traction unit that combines an interior permanent magnet motor and a PM-assisted synchronous reluctance motor for electric vehicles to improve traction performance, enhance energy efficiency, and reduce cost. The characteristics of three traction units are analyzed and compared, including (a) rear-wheel-drive configuration using one IPM motor; (b) all-wheel-drive configuration using two interior permanent magnet motors; and (c) all-wheel-drive with a combination of one interior permanent magnet motor and one PM-assisted synchronous reluctance as proposed in this paper. The operational characteristics of each motor to achieve a wide constant power speed range are first investigated. Then, the Urban Dynamometer Driving Schedule is utilized to compare and evaluate the operational characteristics, energy consumption, and most importantly, the efficiency of the traction units. Simulation results reveal that the overall efficiency of the proposed traction unit can be improved compared to the other configurations. The advantages and drawbacks of the proposed traction unit are also investigated. Finally, experiments are conducted to validate the analysis. [ABSTRACT FROM AUTHOR]

SRM is one of the most attractive electric machines to be used as a S/G in the future MEA thanks to its special physical characteristics that facilitate its direct coupling to the propulsive unit; however, the controllability of the SRG at different operational points, imposed by the specific application, is critical. In this article, a novel active power control scheme which uses a vector-controlled SAF is proposed, in order to efficiently drive the SRG in a wide set point range. Considering the highly non-linearity of the SRM operational behavior, an adaptive phases’ magnetization regulation is applied, aiming at taking full advantage of the SRG's energy production capability, in compliance with the MEA power system specifications and limitations. The mathematical analysis is verified through simulation results, while the SRG concept under study is validated via a RT CHIL implementation. [ABSTRACT FROM AUTHOR]

In this paper, a novel topology for the flywheel battery is proposed, based on the axial split phase (ASP) bearingless switched reluctance machine (BSRM) concept. The topology and operating principle of the ASP-BSRM are explained, the electromagnetic characteristics, torque, suspension force and coupling performance are analyzed by 3-D finite element analysis (FEA). In order to improve the torque and suspension force of the ASP-BSRM, the single variable method by FEA is adopt to screen out the sensitive structure parameters, and a new multi-objective optimization design mothed based on random forest regression (RFR) and differential evolution (DE) is proposed to optimize the key parameters. The 3-D FEA of the complete system is performed, and simulation results verify the proposed topology overcomes the dead zone of suspension force and realize the decoupling between torque and suspension forces. Besides, the optimized torque and suspension force are improved by 4.15% and 12.91%, respectively. An experimental prototype is built to provide an experimental basis for investigation of the actual operating characteristics. The experimental results of the system are evaluated under different operating conditions and compared with FEA results. [ABSTRACT FROM AUTHOR]

A list of regular papers published in the July 2020 issue of "IEEE Transactions on Vehicular Technology" is presented, including "Impact of Big Vehicle Shadowing on Vehicle-to-Vehicle Communications," "Demand-Aware Provisioning of Electric Vehicles Fast Charging Infrastructure" and "Adaptive Switching Spatial-Temporal Fusion Detection for Remote Flying Drones."

This paper makes the case that Switched Reluctance Motor (SRM) is an exceptionally attractive technology to respond to the increasing demand in propulsion applications for high-efficiency, high-performance, and low-cost motors with a more secure supply chain. The paper also presents methods to effectively reduce torque ripple and acoustic noise, which have been the major issues impeding the widespread use of SRMs. Finally, SRM designs for two propulsion motors, one for an e-bike and the other for a hybrid electric vehicle application, are presented which have been proposed to replace permanent magnet machines. [ABSTRACT FROM AUTHOR]

This paper presents the development and control of an electric vehicle (EV) synchronous reluctance motor (SynRM) drive. A bilateral DC/DC converter is used as an interface between the battery and the motor drive. The boostable and well-regulated DC-link voltage with robust regulation control can enhance the motor driving performance in wide speed range. And the regenerative braking energy can be successfully recovered to the battery. In SynRM drive, the robust current PWM switching control considering inherent slotting effects and robust speed model reference control are made. Moreover, an adaptive commutation scheme (ACS) is developed to automatically set the commutation instant for achieving the motor total loss minimization. The dynamic and static driving characteristics of the established EV SynRM drive in various conditions are verified experimentally. [ABSTRACT FROM AUTHOR]

In this paper, an exterior-rotor direct-drive electric bicycle (E-Bike) switched reluctance motor has been designed, based on the performance parameters and dimensional constraints of a commercially available permanent magnet e-bike motor. Motor dimensions have been adjusted to find the best balance between power factor and motor efficiency. The efficiency maps for different rotor pole configurations are compared for 3-phase SRMs with 12 stator poles. The firing angles for each efficiency map operating point are optimized using multi-objective Genetic Algorithm optimization. During the design process, several design parameters have been evaluated and their effects have been investigated. The final design characteristics of the 12/16 SRM e-bike motor are validated experimentally. [ABSTRACT FROM AUTHOR]

This paper presents a switched reluctance motor (SRM) torque ripple reduction strategy with deadbeat current control and active thermal management. In this method, the SRM torque is indirectly controlled by the phase current. A deadbeat current control method is used to improve the SRM phase current control accuracy, so that SRM torque control error can be reduced significantly. According to the online measurement of the power switching device temperature, the switching frequency will be reduced to prevent the SRM power converter from being damaged by over-temperature. The feasibility and effectiveness of the proposed strategy have been verified in both simulation and experimental studies. [ABSTRACT FROM AUTHOR]

This work presents the analysis, design and optimization of a permanent magnet synchronous motor (PMSM) for an electric vehicle (EV) used for campus patrol with a specific drive cycle. Firstly, based on the collected data like the parameters and speed from a test EV on the campus road, the dynamic calculation of the EV is conducted to decide the rated power and speed range of the drive PMSM. Secondly, according to these requirements, an initial design and some basic design parameters are obtained. Thirdly, optimization process is implemented to improve the performance of the designed PMSM. The permanent magnet (PM) structure, airgap length and stator core geometry are optimized respectively in this step. Different optimization processes are proposed to meet multiple optimization objectives simultaneously. Based on the finite element analysis (FEA) method, it is found that the harmonic of the optimized PMSM is lower than that of the initial design, and the torque ripple is reduced by 24%. The effectiveness of optimization on the core loss and PM eddy loss is validated and the temperature rise is suppressed effectively. Finally, a prototype is fabricated for the optimized PMSM and an experimental platform is developed. The test results verify that the optimized PMSM meets the requirements of the specific campus patrol EV well. [ABSTRACT FROM AUTHOR]

This paper investigates the comparative design optimizations of a five-phase outer-rotor flux-switching permanent magnet (FSPM) machine for in-wheel traction applications. To improve the comprehensive performance of the motor, two kinds of large-scale design optimizations under different operating conditions are performed and compared, including the traditional optimization performed at the rated operating point and the optimization targeting the whole driving cycles. Three driving cycles are taken into account, namely, the urban dynamometer driving schedule (UDDS), the highway fuel economy driving schedule (HWFET), and the combined UDDS/HWFET, representing the city, highway, and combined city/highway driving, respectively. Meanwhile, the computationally efficient finite-element analysis (CE-FEA) method, the cyclic representative operating points extraction technique, as well as the response surface methodology (in order to minimize the number of experiments when establishing the inverse machine model), are presented to reduce the computational effort and cost. From the results and discussion, it will be found that the optimization results against different operating conditions exhibit distinct characteristics in terms of geometry, efficiency, and energy loss distributions. For the traditional optimization performed at the rated operating point, the optimal design tends to reduce copper losses but suffer from high core losses; for UDDS, the optimal design tends to minimize both copper losses and PM eddy-current losses in the low-speed region; for HWFET, the optimal design tends to minimize core losses in the high-speed region; for the combined UDDS/HWFET, the optimal design tends to balance/compromise the loss components in both the low-speed and high-speed regions. Furthermore, the advantages of the adopted optimization methodologies versus the traditional procedure are highlighted. [ABSTRACT FROM AUTHOR]

This paper investigates the design principles and performance optimization for segmented-rotor switched reluctance motors (SRSRMs) with different rotor pole numbers for belt-driven starter generators of hybrid electric vehicles. For the design principles, several constraints are derived for the numbers of stator and rotor poles, the dimensions, and the number of winding turns. Two SRSRMs with 16/10 and 16/14 stator/rotor poles are presented according to these principles. For the performance optimization, the two motors are optimized individually for maximizing the torque. To evaluate the effect of different segmented-rotor numbers, the overall performances of the two SRSRMs are investigated and compared. It is found that the 16/14 SRSRM has higher flux linkage and static torque. The 16/14 SRSRM exhibits higher torque and lower torque ripple at low speed operation, whereas at high speed, the 16/10 SRSRM performs better in terms of torque and power densities. Compared with the 16/14 SRSRM, the 16/10 SRSRM has higher final steady speed under the same startup condition. The 16/10 SRSRM can achieve higher steady speed under starter mode and provide higher generated power under braking mode. Moreover, the 16/10 SRSRM exhibits higher efficiency in the most feasible speed range, especially in high speed range, and it has wider high-efficiency area. Finally, a 16/10 SRSRM is prototyped and tested to validate the simulation results. [ABSTRACT FROM AUTHOR]

The conventional field weakening algorithm is more dependent on parameters and computational complexity. Therefore, the concept of advanced angle β is introduced, and the conversion of constant torque operation mode to field weakening operation mode is realized by increasing β. In this paper, the conventional field weakening control and advanced angle field weakening are modeled and simulated showing results that the advanced angle field weakening control can make the motor switch smoothly between the constant torque operation mode and the field weakening mode. The dependence of the parameters of the motor is small and the algorithm is simpler. At the same time, the theory of field weakening control of permanent magnet synchronous motor is fused in the vehicle control and the controller is developed. The external characteristic curve of the motor is calibrated by setting up the back-to-back motor test bench. The function of the controller is verified by hardware-in-the-loop experiment. After vehicle verification, it is confirmed that the data can normally enter the field weakening zone to meet the torque response and high-efficiency range. Under the new European driving cycle (NEDC) operating conditions, the efficiency of the whole controller can reach 81.97%. [ABSTRACT FROM AUTHOR]

This paper presents a novel 12/15 radial field C-core switched reluctance motor (SRM) design, which offers combined advantages of axial field and conventional radial field SRM. In addition, the in-wheel implementation of motor with removable rotor without disturbing stator is one of the unique features. It makes this design more beneficial for electrical vehicle application. This arrangement offers good torque with low excitation current. In this paper, step-by-step design procedure of the proposed radial field C-core SRM is discussed. Parameters are calculated using computer-aided design. These parameters are justified with finite-element analysis and prototype model results. [ABSTRACT FROM AUTHOR]

The trend in traction motor design and optimization is to achieve high torque and power densities, wider speed range, and high efficiency within the area defining the most frequent operating points. A fast tool to evaluate different variables within the torque-speed map is convenient for this purpose. In this context, starting from a preliminary motor design, and taking into account motor cross-coupling effects and power losses, this paper presents a new tool for evaluating the behavior of permanent magnet machines, such as synchronous reluctance machines, and permanent magnet assisted synchronous reluctance machines, in all operational points. Apart from the torque and efficiency, many other electrical variables can be obtained, such as the current space vector angle, power factor or electrical power among others. The proposed tool also allows optimizing the design of the machine under a pre-established control law, thus obtaining the current set point trajectory in the dq frame and allowing a fast and accurate evaluation of motor performance. The results obtained by means of the proposed simulation tool are compared against finite element analysis simulations and experimental data, thus validating the usefulness and accuracy of the proposed methodology. [ABSTRACT FROM AUTHOR]

This study presents a range optimization of a synchronous reluctance motor and a permanent-magnet-assisted synchronous reluctance motor according to a standard driving cycle, and the solutions obtained are compared. The proposed approach avoids the use of a finite-element analysis during the optimization process, thus greatly reducing the time required to obtain the optimal solution. This paper validates the optimal motors obtained in different domains, since the methodology takes into account a multiphysics design. Using two coupled reluctance and thermal networks, all possible working points in the torque–speed plane are obtained taking into account thermal effects, magnetic saturation, iron losses, as well as voltage and current constraints imposed by the inverter. The proposed approach allows a fast comparison of the solutions attained. The design and optimization methodology presented in this study can be applied to any driving cycle. [ABSTRACT FROM PUBLISHER]

This paper introduces an evolutionary optimization procedure for the design of permanent-magnet motors (PMMs) for electric vehicle (EV) applications, considering a specific drive cycle with multiple operating points. For the purposes of the analysis, the New European Drive Cycle (NEDC) has been employed with two alternative PMM configurations. Energy distribution over the NEDC for a small passenger's EV has been calculated and the equivalent multiple operating points have been extracted, using appropriate weights, in order to maintain an equal energy consumption basis, resulting in reduced computational cost. The proposed optimization technique is constituted of an adaptive differential evolution (DE) algorithm involving dynamic variation of the mutation factor, combined with finite-element (FE) and circuit models. The procedure is based on the precise calculation of the two axes input current components for each candidate solution and operating condition. The methodology introduced presents stable and fast convergence characteristics and has been applied to optimize the geometry of both surface-mounted and interior PMM configurations. The proposed motor is based on the thorough tradeoff among the two alternative optimized geometries and has been validated through measurements on a prototype. [ABSTRACT FROM PUBLISHER]

In this paper, an in-wheel switched reluctance motor (IW-SRM) is designed by using a Pareto-based multiobjective differential evolution algorithm (PMODEA) for electric vehicles (EVs). The performance of the IW-SRM varies by the dimension parameters of the motor. Estimation of optimum motor dimensions is a multiobjective optimization problem. In dimension optimization of the IW-SRM for direct-driven EVs, torque, torque per motor lamination volume, and efficiency are specified as objective functions. The PMODEA is proposed for the solution of the multiobjective optimization problem as designing IW-SRM, and nondominant optimum solution set consisting of motor dimensions is obtained. This study provides flexibility to the decision maker, in selection of desired one from the existing solution set. The analysis of the selected motor is realized by considering optimum dimensions via the finite-element method (FEM). Then, the IW-SRM is manufactured, and then, the experimental results are obtained for static and dynamic analysis. FEM analysis results are compared with the experimental results. Eventually, it is observed that the results are satisfactory. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) with a distributed drive train configuration offer great potential and flexibility for improving system efficiency, performance, reliability, and safety. This paper investigates a torque distribution scheme for a front- and rear-wheel-driven microsized EV to improve drive train efficiency over a wide torque and speed range. The loss model of the traction permanent-magnet (PM) motor is characterized in both the constant-torque and flux-weakening regions. The relationship between motor efficiency and torque at a given speed is then derived. It has been shown that maximum efficiency is achieved if the total torque required by the vehicle is equally shared between the two identical motors. In addition, the distribution of the energy consumption over a New European Driving Cycle (NEDC) is analyzed, and the regions of high speed and low torque are identified to have a high level of energy consumption; in these regions, motor efficiency improvement is the most important. Therefore, this paper further proposes to operate just one motor to provide the total required torque in the low-torque region. A clutch may be employed between one motor and gearbox (differential), thus “switching off” its idle loss (no-load loss and flux-weakening loss) and improving drive train efficiency. An online optimized torque distribution algorithm has been devised based on the motor efficiency map to determine whether the second motor should be disengaged by the clutch in the low-torque region. With the proposed optimization scheme, drive train efficiency can be improved by 4% over the NEDC. Experimental test results validate the proposed torque distribution strategy. [ABSTRACT FROM PUBLISHER]

This paper presents a critical review of the drivelines in all-electric vehicles (EVs). The motor topologies that are the best candidates to be used in EVs are presented. The advantages and disadvantages of each electric motor type are discussed from a system perspective. A survey of the electric motors used in commercial EVs is presented. The survey shows that car manufacturers are very conservative when it comes to introducing new technologies. Most of the EVs on the market mount a single induction or permanent-magnet (PM) motor with a traditional mechanic driveline with a differential. This paper illustrates that comparisons between the different motors are difficult by the large number of parameters and the lack of a recommended test scheme. The authors propose that a standardized drive cycle be used to test and compare motors. [ABSTRACT FROM PUBLISHER]

This paper presents an innovative torque control strategy for a switched reluctance machine (SRM) operating in continuous-conduction mode (CCM). The proposed strategy was first designed to control the torque in discontinuous-conduction mode and then extended to operate in CCM as well. With CCM, the torque can be increased at high speed without modifying the number of turns, the source voltage, or the converter; it is achieved through the control. Reviews of past control strategies, as well as the principle of this mode and its influence on the machine performance, are presented. The advantages and drawbacks of the proposed strategy are outlined. In particular, the power and torque densities of the SRM are improved so that this machine becomes comparable with ac machines without the drawback of field weakening. A new control law has been studied and implemented; simulation and experimental results are provided to demonstrate the effectiveness of the proposed control. [ABSTRACT FROM PUBLISHER]

This paper presents three criteria for evaluating the motoring operations of switched reluctance motor (SRM) drives for electric vehicles (EVs). They imply motoring torque, copper loss, and torque ripple, respectively. The effects of the turn-off and turn-on angles on these criteria are investigated under hysteresis current control. To fulfill the best motoring operation, consequently, the multiobjective optimization function is developed by using three weight factors and three groups of base values: the correct balance between the maximum average torque, the maximum average torque per root mean square current, and the maximum torque smoothness factor. The study in this paper shows that the turn-off and the turn-on angles can be optimized to maximize the developed multiobjective function. In addition, the control method for the best motoring operation of SRM drives in EVs is proposed. In this method, two angular controllers are proposed to automatically tune the turn-off and turn-on angles to obtain high motoring torque, low copper loss, and low torque ripple. Simulations and experimental results have demonstrated the proposed optimal control method. Therefore, this paper offers a valuable and feasible approach for implementing the best motoring operation of SRM drives for EVs. [ABSTRACT FROM AUTHOR]

This paper presents a compact battery-powered switched-reluctance motor (SRM) drive for an electric vehicle with voltage-boosting and on-board power-factor-corrected-charging capabilities. Although the boost-type front-end DC/DC converter is externally equipped, the on-board charger is formed by the embedded components of SRM windings and converter. In the driving mode, the DC/DC boost converter is controlled to establish boostable well-regulated DC-link voltage for the SRM drive from the battery. During demagnetization of each stroke, the winding stored energy is automatically recovered back to the battery. Moreover, the regenerative braking is achieved by properly setting the SRM in the regenerating mode. The controls of two power stages are properly designed and digitally realized using a common digital signal processor. Good winding current and speed dynamic responses of the SRM drive are obtained. In addition, the static operation characteristics are also improved. In the charging mode, the power devices that were embedded in the SRM converter and the three motor-phase windings are used to form a buck-boost switch-mode rectifier to charge the battery from utility with good power quality. All constituted circuit components of the charger are placed on board, and only the insertion of power cords is needed. [ABSTRACT FROM AUTHOR]