Design of Unskewed Interior Permanent Magnet Traction Motor with Asymmetric Flux Barriers and Shifted Magnets for Electric Vehicles

Abstract

Interior permanent magnet synchronous motors (IPMSMs) are commonly used in electric and hybrid electric vehicles. Nissan Leaf electric vehicle (EV) uses skewed-rotor IPMSM as a traction motor. This motor is considered as a benchmark in this work. Although, skewing improves the torque quality of the motor by reducing the torque ripple, it reduces the average torque and increases the motor manufacturing complexity and cost. This article proposes improvements to the benchmark motor torque quality without skewing. The proposed motor uses the same stator winding and rotor magnet topologies of the benchmark motor with the same geometric constraints and magnet volume. Modifications are applied to the placement of the magnets in the rotor and the shape of the flux barriers to achieve the performance requirements. The design procedure of the proposed unskewed design is illustrated. Moreover, the electromagnetic performance of the proposed design is investigated. The design shows competitive performance in terms of the average torque, torque ripple, cogging torque, and efficiency compared to the benchmark motor. The mechanical integrity of the design is also verified. The proposed design is found to be a suitable alternative to the benchmark traction motor with a reduced rotor weight and without skewing.     

Distributed Bayesian diagnosis for modular assembly systems—A case study

The growing interest in modular and distributed approaches for the design and control of intelligent manufacturing systems gives rise to new challenges. One of the major challenges that have not yet been well addressed is monitoring and diagnosis in distributed manufacturing systems. In this paper we propose the use of a multi-agent Bayesian framework known as Multiply Sectioned Bayesian Networks (MSBNs) as the basis for multi-agent distributed diagnosis in modular assembly systems. We use a close-to-industry case study to demonstrate how MSBNs can be used to build component-based Bayesian sub-models, how to verify the resultant models, and how to compile the multi-agent models into runtime structures to allow consistent multi-agent belief update and inference.     

A framework for state-space estimation with uncertain models

Develops a framework for state-space estimation when the parameters of the underlying linear model are subject to uncertainties. Compared with existing robust filters, the proposed filters perform regularization rather than deregularization. It is shown that, under certain stabilizability and detectability conditions, the steady-state filters are stable and that, for quadratically-stable models, the filters guarantee a bounded error variance. Moreover, the resulting filter structures are similar to various (time- and measurement-update, prediction, and information) forms of the Kalman filter, albeit ones that operate on corrected parameters rather than on the given nominal parameters. Simulation results and comparisons with ℋ_∞ guaranteed-cost, and set-valued state estimation filters are provided     

Fabrication and modification of polyvinylchloride based heterogeneous cation exchange membranes by simultaneously using Fe-Ni oxide nanoparticles and Ag nanolayer: Physico-chemical and antibacterial characteristics

Polyvinylchloride-blend-styrene butadiene rubber based nanocomposite cation exchange membranes were prepared by solution casting technique. Iron-oxide nanoparticles and Ag-nanolayer were simultaneously utilized as filler and surface modifier in membrane fabrication. The effects of Ag-nanolayer film thickness on membrane physicochemical and antibacterial characteristics of nanocomposite PVC-blend-SBR/Iron-oxide nanoparticles were studied. SEM images showed membrane roughness decreasing by Ag nanolayer thickness increasing. Membrane charge density and selectivity declined by Ag nanolayer coating up to 5 nm in membranes and then showed increasing trend by more nanolayer thickness. Ionic flux also showed increasing trend. Membranes showed good ability in E-Coli removal. 20 nm Ag-nanolayer coated membrane showed better performance compared to others.     

Volatiles Retention in the Drying of Skin Forming Materials PART 2: Natural Materials

ABSTRACT

The retention of ethanol as a simulated flavour was determined by drying single droplets in a horizontal wind tunnel, with fructose, reconstituted skim milk or coffee as the flavour encapaulant. Droplet temperature histories, ethanol content, and crust structure were evaluated for each encapsulant. No enhancement of volatile retention was obtained with the fructose eolutions irrespective of initial concentration, air velocity, or air temperature. Enhancement of the volatiles retention with the coffee and skim milk solutions correlated with an increase in initial solide concentration. resulting from selective diffusion phenomena and the formation of a resistant skin. In both cases air velocity had no significant effect upon volatiles retention. Skin forming materials with similar characteristics would be advantageous for flavour retention.     

Effects of DUT mismatch on the noise figure characterization: a comparative analysis of two Y-factor techniques

Device mismatch seriously degrades accuracy in noise figure characterization. The suitability of corrections to the gain definitions for a more precise noise figure evaluation for mismatched devices is investigated and compared to classical techniques. The effects of device mismatch on the noise figure of the noise-meter receiver and its impact on the final accuracy are analyzed.     

Comparison studies between cement and cement-kaolinite properties for incorporation of low-level radioactive wastes

Comparison between the properties of cement and cement mixed with 7.5% kaolinite was performed to choose the most suitable matrix to incorporate radio-active wastes. The cement-kaolinite mixtures were prepared as uncured, cured, and heated specimens. The physical properties of the cement-kaolinite mixture, namely density, porosity, and water absorption percent, were determined. Compressive strength, infrared spectra, thermal analysis, and the effect of gamma rays on the samples were studied. The studies were extended to the cement-kaolinite mixture in the presence of some chemical additives at different concentrations. Leachability of radioactive isotopes from the cement-kaolinite mixture was measured as a function of time. The physical and mechanical properties of cement were decreased in the presence of 7.5% kaolinite, whereas ¹³⁷Cs and ⁶⁰Co were less leached from the cement-kaolinite mixture.     

Corrosion inhibition of steel by hydrazine

The corrosion inhibition of steel in a closed system containing hydrazine at room temperature has been established. The steady-state potential measurements as well as weight loss measurements agree in indicating that hydrazine was found to behave in a similar manner to anodic inhibitors. A sharp ennoblement of potential occurs at concentration of 10^?2M accompanied by complete protection. The mechanism of inhibition by hydrazine is assumed to be due to its preferential adsorption on the local anodes inducing anodic polarization. After a certain critical concentration of hydrazine is reached complete blocking of the pores occurs which causes complete inhibition. For hydrazine-sulphate or hydrazine-chloride mixtures, a linear relationship is found between log hydrazine concentration and log maximum tolerated concentration of the aggressive ion. For hydrazine-sulphide mixtures, a concentration of 5 × 10^?2M hydrazine could tolerate a wide range of concentrations of sulphide ions.