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Renewable energy sources generate power intermittently, which poses challenges in meeting power demand. The use of transient energy storage systems (TESSs) has proven to be an effective solution to this issue. Hence, it is crucial to understand the impact of TESS components design on sizing the power‐train system during fast frequency response. While power‐train systems have been extensively discussed, the impact of dc‐link voltage on the TESS power‐* train and associated power electronics specification requirements has not been evaluated. This study uses a sodium‐nickel chloride (NaNiCl2) battery‐based TESS to assess different power‐train options. Specifically, the research investigates the impact of variations in dc‐link voltage due to battery regulation and state‐of‐charge (SoC) on the design of the TESS‐connected power‐train system, since these will be the major contributions to the power‐train system performance envelope. This paper also compares the performance of TESS power‐train systems with four different schemes. The power‐train models include the detailed modelling of energy sources, power electronic converters, and transformers based on published parameters and testing data. Additionally, the study proposes a performance index to evaluate the superiority of the four schemes in terms of voltage and current rating, efficiency and battery size. [ABSTRACT FROM AUTHOR]

This paper presents results from a design study on the feasibility of employing high-efficiency switched reluctance (SR) machines in minimal hybrid-electric vehicles. The application requirements are presented and highlight the constraining influences of the vehicle drive-line topology on the machine design. The benefit of continuous phase current excitation is reported for the first time, demonstrating that constant power at an extended-speed operation can be realized with a higher number of phase winding turns per pole than would otherwise be achieved with conventional discontinuous current control. Thus, the torque/Ampere capability, when operating at or below base speed, is not as significantly compromised, an important consideration for the power inverter rating and, hence, drive system cost. The design procedure and simulated results are validated by measurements from a prototype machine. The results demonstrate the potential of SR technology for high-performance low-cost automotive applications, which often combine arduous environmental and volumetric constraints. In addition, the results highlight the benefits of continuous current control for extended-speed operation. Index Terms--Automotive power-trains, electric vehicles, minimal hybrid-electric vehicles, switched reluctance machines.

Switched reluctance (SR) drive systems are a candidate technology for electric vehicle applications, particularly where a high degree of component integration is required within a thermally demanding environment--typical of engine-mounted power-assist solutions. This paper discusses the design, prototype realization, and test validation of an SR machine for a mild-hybrid power-assist starter/alternator application that has performance requirements of both high starting torque and a wide speed range at full power. While a number of papers on SR machine design for automotive starter/alternator applications have been published, a comprehensive case study discussing the design and application issues has not been published. This paper focuses on the impact of the performance requirements and volumetric and environmental constraints on the machine design. It is shown that a higher number of stator and rotor poles is more appropriate for the utilization of the available active volume. While various operation and fault scenarios have been presented for SR drive systems, this paper also discusses test observations that suggest the potential for the transient self-excitation of the SR generator via residual magnetization of the machine rotor--a fault scenario that has only been briefly reported on. Index Terms--Machine design, mild-hybrid electric vehicles, starter/generators, switch reluctance machines.

This paper provides systematic analysis and controller design methods for high-performance two-mass servo drives with an appraisal of the effects of supplementary filtering elements associated with practical systems. Implementation issues and the resulting performance achievable from proportional-integral, proportional-integral-derivative (PID), and resonance ratio control (RRC) controllers with regard to both closed-loop robustness and control of the process variable (load velocity), in response to a step reference speed or load-side disturbance, are presented. It is shown that the high-frequency gain of the controllers is a critical design variable for determining the resulting robustness of the closed-loop system when subject to unmodeled resonant modes, high-frequency noise from the derivative of quantized sensor signals, and process perturbations, and is strongly influenced by the location and number of filters present in the various feedback loops and, importantly, the ratio of their time constants. A complete design methodology is also presented to assign the time constants of the various loop filters, and their location, using a single user-definable variable, thereby reducing the time-consuming trial-and-error approach commonly employed using conventional tuning procedures. The technique employs both time- and frequency-domain design tools to address the conflicting requirements of robustness and control performance (overshoot, bandwidth, etc.). It is also shown that, since the PID and RRC controllers are closely related, they are theoretically able to impart identical closed-loop input-output dynamics. However, by virtue of the different feedback mechanisms employed, RRC is shown to provide superior closed-loop robustness. This paper demonstrates, and practically validates, the proposed techniques by showing significant performance enhancements from a commercial off-the-shelf servo-drive test platform. Index Terms--Acceleration control, motion control, resonance, robustness, surface acoustic wave devices, torque control, velocity control, vibration control.

This paper proposes controller design and tuning methodologies that facilitate the rejection of periodic load-side disturbances applied to a torsional mechanical system while simultaneously compensating for the observer's inherent phase delay. This facilitates the use of lower-bandwidth practically realizable disturbance observers. The merits of implementing full- and reduced-order observers are investigated, with the latter being implemented with a new low-cost servo-machine-integrated high-bandwidth torque-sensing device based on surface acoustic wave (SAW) technology. Specifically, the authors' previous work based on proportional-integral-derivative (PID) and resonance ratio control (RRC) controllers (IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1226-1237, Aug. 2006) is augmented with observer disturbance feedback. It is shown that higher-bandwidth disturbance observers are required to maximize disturbance attenuation over the low-frequency band (as well as the desired rejection frequency), thereby attenuating a wide range of possible frequencies. In such cases, therefore, it is shown that the RRC controller is the preferred solution since it can employ significantly higher observer bandwidth, when compared to PID counterparts, by virtue of reduced noise sensitivity. Furthermore, it is demonstrated that the prototype servo-machine-integrated 20-N * m SAW torque transducer is not unduly affected by machine-generated electromagnetic noise and exhibits similar dynamic behavior as a conventional instrument inline torque transducer. Index Terms--Filter noise, motion control, motor drives, observers, resonance, state feedback, surface acoustic wave (SAW) devices, velocity control.

This paper provides a systematic comparative study of compensation schemes for the coordinated motion control of two-inertia mechanical systems. Specifically, classical proportional-integral (PI), proportional-integral-derivative (PID), and resonance ratio control (RRC) are considered, with an enhanced structure based on RRC, termed RRC+, being proposed. Motor-side and load-side dynamics for each control structure are identified, with the 'integral of time multiplied by absolute error' performance index being employed as a benchmark metric. PID and RRC control schemes are shown to be identical from a closed-loop perspective, albeit employing different feedback sensing mechanisms. A qualitative study of the practical effects of employing each methodology shows that RRC-type structures provide preferred solutions if low-cost high-performance torque transducers can be employed, for instance, those based on surface acoustic wave technologies. Moreover, the extra degree of freedom afforded by both PID and RRC, as compared with the basic PI, is shown to be sufficient to simultaneously induce optimal closed-loop performance and independent selection of virtual inertia ratio. Furthermore, the proposed RRC+ scheme is subsequently shown to additionally facilitate independent assignment of closed-loop bandwidth. Summary attributes of the investigation are validated by both simulation studies and by realization of the methodologies for control of a custom-designed two-inertia system. Index Terms--Acceleration control, motion control, resonance, surface acoustic wave (SAW) devices, torque control, velocity control, vibration control.

The testing of scale model propulsors is an essential part of any marine propulsion design process. The fluctuating force module (FFM) is a self contained, instrumented propulsor drive system designed to be an integral part of a scaled propulsor test facility. The paper describes a novel electromagnetic test facility which provides a static axial thrust of 0-1 kN and triaxial dynamic forces of 0.3-3 Nrms, at frequencies of 80-800 Hz, to an equivalent propulsor mass rotating at speeds of 0-900 rpm, in order to calibrate the FFM force measurement systems. Index Terms--Permanent magnet actuators, propulsor calibration facility, static and dynamic force actuators, surface acoustic f wave force measurement.