Analytical Design Procedure Research Articles

A Manufacturing Driven Design Methodology to Lightweighting of the Structural Elements of a Permanent Magnet Electrical Machine Rotor

It is common practice for electrical machines to be designed with a focus predominantly on the electromagnetic performance. The mechanical design is then subsequently undertaken to meet various mechanical performance criteria, with this finalised design then passed on for manufacture. In many cases, the manufacturing constraints have not been taken fully into consideration during the electromagnetic or more particularly the mechanical design and hence some changes are required to the design to make it manufacturable. This in turn can lead to a non-optimal machine being manufactured. If manufacturing constraints and opportunities are regarded as key quantitative inputs to the design process, not only can these post-design changes be minimised, but benefits of the manufacturing process can be exploited to produce a superior product. This paper proposes a methodology to fully integrate the mechanical design and manufacturing process routes into electrical machine design and illustrates its utility within the context of light-weighting of a permanent magnet rotor for an aerospace electrical machine. Within the proposed methodology, several alternative configurations of the rotor are considered with applicable manufacturing routes identified at the initial stages of design and an analytical design procedure to fulfil the application and performance criteria is developed. Different manufacturing materials and constraints as well as the impact of manufacturing process are identified to be embedded into the design procedures. Finally, the paper demonstrates an application of this methodology together with a discussion of the features which offer promise in achieving economically lighter weight design through integration of manufacturing into the design procedure.

Contribution of the generalized nonunique inverses to the minimum-energy control theory: The inverse model control investigation

The innovative analytical approach to the minimum-energy design problem of the inverse model control (IMC) state-space structures is presented in this work. Following the recent papers, it should be concluded that the optimal behavior of the IMC strategy cannot longer be associated with the application of the well-known Moore–Penrose minimum-norm inverse. However, the minimum-energy IMC-oriented scheme has only be obtained through heuristic methods. Nevertheless, in the recent authors’ work, it has been proven for the first time that such an issue can be considered in an analytical manner. Yet, the obtained results have only been valid for the second-order state-space systems. Therefore, the motivation instance proposed in the manuscript, confirming the possibility of extending such paradigm to higher-order plants, will certainly contribute to the introduction of the new unified minimum-energy IMC theory canon. Since the nonunique σ and H inverses can successfully be employed in the robustification of the discussed control strategy, they can also be helpful in the case of our essential considerations. Thus, from now on the yet unexplored research area can now be investigated in the analytical manner, what has never been seen before in the modern IMC-originated control theory and practice. The predefined methodology clearly fills the gap in the analytical control design procedures and opens a new chapter in the knowledge related to the well-known and broadly accepted multivariable control canons.

Labour market localisation policies and organizational responses: an analysis of the aims and effects of the Saudi Nitaqat reforms

PurposeThe aim of this paper is twofold. First, to understand the degree to which the intended outcomes of Saudi’s Nitaqat labour market policy corresponds to the actual responses from private companies. Second, to investigate how these gaps between policy intentions and actual outcomes have informed recent changes to Nitaqat policy.Design/methodology/approachThis paper uses a qualitative approach with a case study design and thematic analysis procedures. Data were obtained from the following three sources: semi-structured interviews completed during the early stage of Nitaqat in 2013–2014 with nine policymakers and 44 key stakeholders from six private Saudi companies; policy documents and gray literature on the aims and effects of the Nitaqat program; and available peer-reviewed literature on the subject.FindingsThis paper sets out and analyses the following four main goals of Nitaqat: First, to increase the Saudi national employment rate, second, increase company efficiency, third, improve human resource capabilities, and fourth, increase female labour participation. This paper reveals that although Nitaqat has certainly resulted in a positive change in some of these areas, in other areas, there remain gaps between the intentions and the actual effects of Nitaqat. This paper analyses recent changes to Nitaqat and argues that further changes may be needed to achieve the full goals of Nitaqat.Originality/valueThis paper’s originality lies in its analysis of the aims of labour market policies and organisational responses. It highlights the reasons for disconnections between the policy aims and organisational practices and explores how policymakers react and respond to these implementation gaps.

On the Electromagnetic Performance Prediction of Turbo Synchronous Condensers Based on Wound-Field Flux Switching Machine Design

The revival of the old synchronous condenser (SC) technology is presently occurring. Hence, this study is proposed on the electromagnetic design and evaluation of turbo wound-field flux switching machines (WF-FSMs) for SC operation, for the first time. Unlike classical wound-field rotating machines, WF-FSMs do not need brushless exciters while possessing a robust topology. A design process based on the frozen permeability technique in static 2-D finite element analysis script-based package, which enhances both iterative and analytic adjudications, is proposed to accurately predict the SC operation. To attain the specific design requirements (~300 MVAR, 16 kV), a global-optimized model (GOM) of the SC machine is obtained through a stochastic optimization process involving multiple objectives. Based on the GOM, simple torque ripple minimization techniques are implemented, from which a final benchmark design is selected. The proposed SC analytical design procedure is then tested and the expected V-curves clearly obtained. The whole design approach is further verified by experimenting on a small-scale prototype, which when synchronized to the grid, confirms the novelty and feasibility of the proposed SC design and operation.

Design of External Rotor Ferrite-Assisted Synchronous Reluctance Motor for High Power Density

The rare-earth (RE) permanent magnets (PM) have been increasingly adopted in traction motor application. However, the RE PM is expensive, less abundant, and has cost uncertainties due to limited market suppliers. This paper presents a new design of a RE-free five-phase ferrite permanent magnet-assisted synchronous reluctance motor (Fe-PMaSynRM) with the external rotor architecture with a high saliency ratio. In such architecture, the low magnetic coercivity and demagnetization risk of the ferrite PM is the challenge. This limits the number of flux barriers, saliency ratio, and reluctance torque. A precise analytical design procedure of rotor and stator configuration is presented with differential evolution numerical optimizations by utilizing a lumped parameter model. A 3.7 kW prototype is fabricated to validate the proposed idea.

Optimization of honeycomb sandwich floor panels made of polymer-matrix low-combustible composite materials based on high-strength carbon and glass fibers and adhesive binder

The article deals with the task of designing aircraft honeycomb sandwich floor panels considering experimental data on the mechanical properties of new high-strength low-combustible composite materials. The developed experimental and analytical design procedure and optimization algorithm are described. The design task is formulated in terms of nonlinear mathematical programming in which the mass per square meter of the construction is the objective function. The thickness of the base layers, the height of honeycomb core and some other parameters are considered as the design variables. The proposed visual interpretation of the optimal design task allows reducing possible design solutions based on the experimental data to an enumeration of a limited number of design alternates. The article presents a demo task and the results of designing floor panes for an advanced passenger aircraft in the aisle area using a new low-combustible composite material. The floor panel is regarded as a continuous multiply supported plate loaded with distributed load. The proposed grapho-analytical method makes it possible to form the area of rational designs that differ from the optimal one in terms of mass by a specified allowable value. The performed computational and experimental analysis shows that with the use of the new material, a floor panel can be designed with base layers made of carbon or fiberglass and lightweight honeycomb filler with the mass of a square meter from 2,9 to 3,4 kg, which is the state-of-the-art.

Optimal design of proportional‐resonant controller and its harmonic compensators for grid‐integrated renewable energy sources based three‐phase voltage source inverters

This paper proposes new analytical and optimal design procedures of the proportional-resonant (PR) controller and its harmonic compensators (HCs) for three-phase grid-connected voltage source inverters (VSIs) powered by renewable energy resources. The modeling and analysis based on stationary reference frame are performed for VSIs collaborated with an L-type filter. The theoretical verification and simulation validation of the proposed design guidelines are done to approve its effectiveness and robustness. Particle swarm, grey wolf and Harris hawks' optimization techniques are applied and compared for a proper selection of the parameters of the proposed PR controller and its HCs. To accomplish this study, multi-objective error functions are employed and compared to minimize the total harmonic distortion of the grid output current. The proposed PR controller and its HCs are tested, using MATLAB/Simulink, along with the allowable changes of inverter output active and reactive powers, and also under the grid voltage distortion. Moreover, their performance is evaluated according to IEEE and IEC harmonics standards, and compared with the conventional PI controller based on reference frame. Furthermore, the experimental validation for the proposed controllers is done based on the hardware-in-the-loop real-time simulator using C2000TM-microcontroller-LaunchPadXL-TMS320F28377S kit.

Psychological Test Feedback: Canadian Clinicians’ Perceptions and Practices

This study explores Canadian clinicians’ perceptions of test feedback (TFB) and how those perceptions influence their practice. This secondary analysis of open-ended qualitative data extends a previous study with similar research questions conducted by Jacobson et al. (2015). A case study design and consensual qualitative research (CQR) data analysis procedure was utilized to enhance the trustworthiness of the results. The findings indicate that clinicians give TFB in a variety of settings. Clinicians emphasize the importance of providing tailored and collaborative TFB, of attending to ethical issues related to TFB, and of improving academic training in TFB. Also, clinicians discuss unique situations in which feedback is provided to a third party rather than to the testing individual. Clinical implications such as increased practical training for providing TFB are discussed. Future research could investigate the outcomes of TFB provision.

An integrated performance‐based design framework for building‐foundation systems

AbstractThis paper presents a framework for the inclusion of transient and residual foundation deformations within performance‐based seismic design of buildings. A refinement of existing displacement‐based design procedures is proposed that reduces iteration when obtaining the expected peak foundation rotation. Empirical equations are developed based on numerical time‐history analyses that provide an estimation of foundation residual deformations based on the foundation peak rotation. Additional complexities due to deformation within the foundation are discussed regarding how they influence the design and building performance. The design framework is complemented by a simplified analytical design procedure (i.e., hand calculations) to design building‐foundation systems. A design example is given for a six‐storey concrete wall building, which is analyzed by time‐history analysis to demonstrate the application and accuracy of the design procedure.

Multiband and Broadband Interference-Free Metallic Package Designs for Microwave Modules

This letter presents a technique for designing metallic packages and cavities hosting RF and/or digital electronic systems for minimizing the unintentional coupling due to cavity resonances. The method involves an appropriate design of the conductive lid by adding periodic structures, unit cells (UCs), characterized by metal pins of appropriate length. The technique proposed herein, based on a quick analytical design procedure, demonstrates that the use of two different UCs arranged by following specific layouts is able to offer either multiple bandgaps or an ultrawide bandgap. Three UCs geometry are analyzed for bandgaps at $X$ -, Ku -, and $K$ -bands; they are combined to achieve the two above-mentioned bandgap responses aimed at $X$ – Ku and $X$ – $K$ band applications. Both full-wave simulations and experimental results confirm the validity of the proposed technique.

Gaussian Circular 2D FIR Filters Designed Using Analytical Approach

This paper proposes an analytical design procedure for a particular class of 2D filters, namelyGaussian-shaped, circularly-symmetric FIR filters. We approach both low-pass and band-pass circular filters,which are adjustable in selectivity and peak frequency. The design starts from a given 1D Gaussian prototypefilter, approximated using the Chebyshev series. A frequency transformation is applied to derive the circularfilter. Several design examples are provided for both types of filters. The filters designed through this methodare efficient, their frequency response results in a factored or nested form, convenient for implementation.

Analytical design, electromagnetic field analysis and parametric sensitivity analysis of an external rotor permanent magnet-assisted synchronous reluctance motor

This paper deals with analytical design, electromagnetic field analysis and parametric sensitivity analysis of an external rotor permanent magnet-assisted synchronous reluctance motor (PMASynRM). In this work, parametric sensitivity analysis of rotor geometry is performed to obtaining the minimum torque ripple and maximum electromagnetic torque with employing numerical analysis based on two-dimensional finite element method (FEM). In order to determine the optimum operation effect of geometry parameters like the q axis insulation ratio and the flux barrier arm angle for the proposed machine with three barriers is investigated and sensitivity of structure for rotor geometrical variation is presented. The studied machine in this work is a three phase, six pole, external rotor PMASynRM, which is designed by analytical approach and analyzed to obtain the maximum torque and minimum torque ripple based on a parametric sensitivity analysis approach. The obtained results from the FEM-based sensitive analysis and electromagnetic field analysis confirm the analytical design procedure for the proposed PMASynRM.

Compact coupled resonators for small size dual‐frequency wireless power transfer (DF‐WPT) systems

This work introduces a novel design for high efficiency and compact size dual-frequency wireless power transfer (DF-WPT) systems. The proposed design is composed of two identical transmitting (Tx) and receiving (Rx) substrates. Each substrate has a microstrip feed line, a C-shaped coupled resonator on the top layer and a spiral coupled defected ground structure on the bottom layer. The system is analysed using J-inverters for the dual-frequencies (DFs) operation. The measured results show that the proposed DF-WPT system with a compact size of 20 × 20 mm2 is able to provide a stable WPT characteristic with total efficiencies of 91.2 and 79.4% at 0.28 and 0.49 GHz, respectively with a transmission distance of 6 mm. The proposed system achieved good agreements between the analytical design procedure, the circuit model, the electromagnetic simulations, and the measurements.

Proposition of a simplified analytical design procedure for lattice girder slabs with shuttering in cold-formed steel lipped channel section

ABSTRACT This paper presents an analytical procedure to determine the resistance of a new composite ribbed lattice slab system, composed by a lipped channel cold-formed steel (CFS) profile in minor bending fastened to a lattice girder by plastic connectors, as well as light filling elements and additional rebar. Motivated by the lack of standardized procedures for such system, this paper combines slab design prescriptions to create a computational tool that estimates load capacity and required propping during construction, serving as a basis for a design catalogue. Finally, a strong limitation of unpropped construction due to the low performance of the cold-formed profile under minor axis bending was observed, being the system able to reach spans up to 1.5 m between props in general.

A new gm-boosting design technique for wideband inductorless low-noise transconductance amplifiers

In this paper, a new gm-boosting design technique for wideband inductorless low-noise transconductance amplifiers (LNTA) is presented, resulting in optimal input matching, and noise and linearity performance. The proposed technique in its basic form, relaxes the constraint on transconductance value of conventional gm-boosted common-gate LNTAs so that the overall transconductance can be selected regardless of input matching condition. In addition, the technique can be reconfigured for either optimum noise performance or linearity improvement while imposing negligible power and area overhead. Analytical derivation and practical design procedure for both task is thoroughly discussed. Implemented in a standard 0.18 μm CMOS process, for a reasonable power consumption of 6.7 mW, the proposed LNTA achieves about 24 mS transconductance and a minimum NF of 3.4 dB over a bandwidth of 0.4–2.1 GHz.

Lower order controller design using weighted singular perturbation approximation

Most of the analytical design procedures yield controllers of almost the same order as that of the plant. Resultantly, if the plant is of a high order, the controller obtained from these design procedures is also of a high order. The order of the controller should be practically acceptable for easy implementation. There are two indirect methods for designing a low order controller for high order plants: plant reduction and compensator reduction. In compensator reduction, the order of the controller designed for the original higher order plant is reduced. In plant reduction, the order of the plant is reduced for designing a lower order controller. The order of the controller or plant is reduced using model order reduction techniques. In this paper, we propose a hybrid algorithm (plant-compensator reduction) based on frequency-weighted singular perturbation approximation, which gives an improved performance as compared to existing algorithms. The proposed hybrid technique can be used with $H_{\infty}$, LQG, or any other loop shaping procedures to obtain a lower order controller. The proposed technique is validated on benchmark control problems.

Power divider based on vertical elliptical directional couplers with increased isolation and bandwidth

In this study, a novel high-isolation wideband divider based on multi-layer elliptical defected ground structure coupler is presented along with its analytical theory and design procedure. The proposed divider could be conveniently applied for high- power applications with less loss for the absence of isolation resistors. The simulation results show that in 3.1–10.6 GHz, the return loss S11 and S22 are −4 dB within 4–9 GHz, and the amplitude and phase difference between port 2 and port 3 is <1 dB and 2°, respectively.

Weighting Factors Optimization of Predictive Torque Control of Induction Motor by Multiobjective Genetic Algorithm

This study investigates the application of a multiobjective genetic algorithm for the obtaining of a set of weighting factors suitable for use in the model predictive torque control (MPTC) of an induction motor variable speed drive. The MPTC approach aims at minimizing a cost function at each step and has been highlighted for its fast torque response, easy incorporation of system constraints, and absence of voltage modulators. Nevertheless, its structure contains weighting factors in the cost function, which lacks an analytical design procedure. The nondominated sorting genetic algorithm II (NSGA-II) was designed for a tradeoff between torque and flux performances and average switching frequency of the system. Experimental results showed NSGA-II offered a Pareto set of feasible solutions, so that torque ripple, flux ripple, or average switching frequency can be minimized, depending on the solution chosen. Its application constitutes a project tool for MPTC weighting factors that adjusts several factors concomitantly and incorporates desired restrictions.

Low Leakage Electromagnetic Field Level and High Efficiency Using a Novel Hybrid Loop-Array Design for Wireless High Power Transfer System

In this paper, we first proposed a novel hybrid loop array (HLA) for low leakage electromagnetic field (EMF) level and high efficiency in a wireless high power transfer system. The proposed HLA effectively enhances the system efficiency and shields leakage EMF in a wireless power transfer (WPT) system using kHz range resonant frequency. The key originality of the proposed HLA is the combination of two types of loop coil; shielding loop coil (SLC) and amplifying loop coil (ALC). SLCs reduce leakage EMF, and ALCs significantly enhance the magnetic field from a Tx coil. The simulation and experiment results show that the proposed solution successfully overcomes the limitations of the existing solutions. Analytical modeling and design procedure are introduced and discussed. In addition, the experimental verification of the simulation result is included. We first designed and modeled an HLA considering the coupling effect of neighboring loop coils to evaluate its efficiency and leakage EMF. With the proposed HLA, we demonstrated a 9.36% improvement in the efficiency and 3 dBm reduction in the leakage EMF near the WPT system.

Dispersion-Engineered Guided-Wave Resonators in Anisotropic Single-Crystal Substrates - Part II: Numerical and Experimental Characterization.

In this part of the paper, numerical and experimental verification of the analytical design procedure is presented. Various waveguide-based test-vehicles, implemented in single crystal silicon and transduced by thin aluminum nitride films, are demonstrated. Silicon resonators with type-I and type-II dispersion characteristics are presented to experimentally verify the analytical mode synthesis technique for realization of high quality-factor silicon Lamb wave resonators.