Electric vehicles (EVs) are propelled by electric traction drive systems (ETDSs), which consist of various components including an electric motor, power electronic converter, and gear box. During ...manufacturing, end-of-line testing is the ultimate step for ensuring the quality and performance of electric motors in electric vehicle (EV) traction drive systems (ETDSs). The outcome of end-of-line testing of electric motors is significantly influenced by the tolerances of their structural parameters, such as stator inner and outer diameters, magnet dimensions, air gaps, and other geometric parameters. The existing literature provides insights into parametric sensitivity, offering guidance for enhancing the reliability of end-of-line testing. In this manuscript, the importance of end-of-line testing and the role of manufacturing tolerances of e-motor structural parameters in the manufacturing process of ETDSs are discussed. The impact of tolerances of e-motor structural parameters on the test results, such as torque, efficiency, back EMF, and e-NV (noise and vibration), is investigated. Finally, key challenges and research gaps in this area are identified, and recommendations for future research to mitigate the drawbacks of end-of-line testing are provided.
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This paper investigates the torque ripple modeling and minimization for interior permanent magnet synchronous machines (PMSMs). At first, a novel torque ripple model is proposed in which the torque ...ripples resulted from the spatial harmonics of permanent magnet flux linkage, time harmonics of stator currents and the cogging torque are included. Based on the torque ripple model, a genetic algorithm (GA)-based harmonic current optimization approach is proposed for torque ripple minimization. In this approach, GA is applied to optimize both the magnitude and phase angle of the stator harmonic currents to minimize the peak-to-peak torque ripple, minimize the sum of squares of the harmonic currents, and maximize the average torque component produced by the injected harmonic currents. The results demonstrate that the magnitude of the harmonic current can be significantly reduced by optimizing the phase angles of these harmonic currents. This leads to further suppression of the torque ripple when compared with that of a case where phase angles are not considered in the optimization. Also, an increase of the average torque is achieved when the optimum harmonic currents are injected. The proposed model and approach are evaluated through both numerical and experimental investigations on a laboratory interior PMSM.
Integrated charging technology in electric vehicles is expected to reduce the overall cost as well as the weight of the vehicle, while leading to fast charging capability in the vehicle. ...Understanding the above, this paper puts an effort to exclusively investigate interior permanent magnet synchronous machine (IPMSM) drive incorporating damper bars in rotor for integrated charging application in electric vehicles. First, motivation for the employment of IPMSM with damper bars for integrated charging is provided and justified. Thereafter, a novel parameter determination method based on dq-axis theory to determine the parameters of a laboratory IPMSM with dampers is proposed and experimentally validated. The determined parameters are then employed to design, control, and compare the performance of an integrated charging system incorporating an IPMSM drive with and without damper bars. The developed system is then experimentally tested under both vehicle-to-grid and grid-to-vehicle modes, and results elicited from the investigations are discussed.
Power electronics and motor drive components existing in a conventional electric vehicle (EV) drivetrain employed to propel the EV can also be used to charge the battery under level 3 fast charging ...capacity. This integrated battery charging technology can be realized by employing the winding inductances of the three-phase interior permanent magnet synchronous motor (IPMSM) used for propulsion as line inductors while charging the EV's battery pack. The difference in the d - and q -axis inductances in the IPMSM offers unbalanced Thevenin impedances as viewed from stator terminals. This causes the voltages across the stator windings to become unbalanced when balanced three-phase currents synchronized with the grid utility voltages are forced into the three armature phases during charging. This paper first presents a case study employing a conventional laboratory IPMSM to illustrate the unbalanced phase winding impedance during an "emulated integrated charging" operation. Thereafter, the authors derive motivation to design and analyze an IPMSM with dampers in the rotor for propulsion and mitigation of the saliency effect, that is, the effect of unequal armature phase impedance at standstill during integrated charging. A novel design approach is presented and employed to design an IPMSM with dampers. Performance of the designed IPMSM with dampers is compared to that of the conventional IPMSM under both integrated charging and traction conditions. The proposed design is also validated experimentally using a laboratory IPMSM with dampers.
During integrated charging (IC) from a single phase ac utility employing permanent magnet machines, the magnetic field produced by the sinusoidal ac current passing through the stator windings: 1) ...affects the effective winding inductance used in the charger circuit as a function of different stator winding combinations and 2) produces oscillating torque of varying magnitudes as a function of rotor position. Understanding these challenges, this paper exclusively investigates the electromagnetic effects inside a surface-mounted permanent magnet synchronous machine (SPMSM) when it is used for IC operation in electric vehicles. Variation of oscillating electromagnetic torque magnitude as a function of rotor angle is investigated through finite-element analysis, and recommendations are provided to determine the lowest torque position favorable for IC operation. Thereafter, numerical investigations are conducted for five different stator winding combinations to analyze the issue of varying effective inductance as a result of magnetic coupling in the motor. Furthermore, a mathematical model is developed to obtain these inductances in the five winding configurations. Finally, the numerical investigations are validated by performing experimentations on a 21 hp SPMSM.
Understanding the need for steady-state and transient performance improvement in an interior permanent-magnet synchronous machine (IPMSM) drive, this paper exclusively investigates the IPMSM ...incorporating damper bars in the rotor of electric motor for electrified vehicles (EVs). First, motivation for the employment of damper bars in IPMSM is provided and justified with a case study. Thereafter, a mathematical model of an IPMSM drive with damper bars in the rotor has been developed based on dq-axis theory and validated through experiments performed on a laboratory IPMSM containing damper bars. The validated mathematical model has been then employed to arrive at satisfactory rotor bar parameters for an existing IPMSM on board a commercially available EV. Moreover, a replica of the existing onboard EV motor with and without incorporating dampers have been designed, and finite-element analysis has been performed to investigate various performance characteristics. Comparative performance analyzes of both the machines with and without damper bars under steady-state and transient conditions have been performed wherever necessary, and the results elicited have been discussed.
In this paper, three Vernier permanent-magnet (VPM) motor, namely the inner-rotor VPM (IR-VPM) motor, the outer-rotor VPM (OR-VPM) motor and the OR consequent-pole VPM (OR-CP-VPM) motor are proposed ...for the hybrid electric vehicle (HEV) applications. Owing to employment of toroidal-winding arrangement, the OR-VPM and the OR-CP-VPM motors can enjoy better material utilization and easier manufacturing process than its IR-VPM counterpart. Meanwhile the OR-CP-VPM motor can utilize the consequent-pole topology to minimize flux leakage that exists in conventional design. With the support of finite element method (FEM), the motor performances among the VPM motors and the profound interior permanent-magnet (IPM) motor can be compared quantitatively.
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This paper presents challenges in an ongoing project related to the design of a premium efficiency three-phase line start permanent magnet synchronous motor (LSPMSM) and proposes an exclusive ...solution through development of a novel magnetic circuit model. Since the LSPMSM is rapidly replacing the conventional induction motors in industrial applications such as pumps, fans and conveyors which require the machine to operate under both frequent start-stop and steady-state conditions for a wide range of time, a trade-off has to be reached between their starting performance and efficiency post-synchronization. Until now this has only been possible with time consuming FEA based design methodology. Hence, understanding the need and scanty availability of literature on simplistic and yet precise magnetic circuit based design of three-phase LSPMSM, this manuscript proposes exclusively a novel magnetic circuit model to design LSPMSM with improved starting performance. Firstly, the aforementioned design issues have been illustrated using different machine configurations developed. Further, a detailed procedure to deal with the design issues with the help of the developed magnetic circuit model is discussed and validated by developing a machine where the trade-off has been reached.
For permanent magnet synchronous machines (PMSMs), high performance control strategies rely on sensors to obtain accurate information of rotor position and speed. However, mechanical sensors are ...expensive and susceptible to harsh environment. Therefore, various sensorless control strategies have been proposed and intensively investigated for decades. Among them, sliding mode observer (SMO) based sensorless control method has drawn increasing attention due to its simple implementation and strong robustness. This paper presents a comprehensive review of SMO based sensorless control strategies for PMSMs reported in the literature. State-of-the-art SMO based sensorless control strategies have been reviewed and investigated, and the design of SMO under non-ideal conditions is presented as well. In addition, future research trends for SMO based sensorless control strategies are also discussed.
Understanding the importance and the scanty availability of research literature on parameter estimation of line-start permanent magnet synchronous machine (LSPMSM), this paper proposes a novel and ...yet fundamental approach towards parameter estimation. Experiments have been performed on a laboratory LSPMSM based on the proposed dq axis methodology and measurements have been validated by analyzing the performance of the machine under different conditions using a developed computer program and an experimental setup. Dynamic and steady state performance analyses have been subsequently performed using the determined parameters and the results have been presented under direct online (DOL) starting and a sudden increase in load torque.
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