Search results
1 – 5 of 5The purpose of this paper is to present a simple and effective method to search the optimal turn-on and turn-off angles on-line for the control of the switched reluctance motor…
Abstract
Purpose
The purpose of this paper is to present a simple and effective method to search the optimal turn-on and turn-off angles on-line for the control of the switched reluctance motor (SRM). The optimal turn-on and turn-off angles are defined as the ones that can meet torque production requirements with minimum copper loss.
Design/methodology/approach
The optimal turn-on and turn-off angles are first defined based on the analysis of the SRM losses and torque production principles. Then the algorithm for optimal angles searching is developed, and the searching parameters are determined through analytical computation. The optimal angles are approached on-line with iterative process. Simulation and experiments are finally performed to verify the proposed method.
Findings
The presented method can meet torque production requirements while copper loss is minimized. The optimal turn-on and turn-off angles are generally approached within five phase cycles for most of the SRM operation modes. Furthermore, the SRM drive system using the presented method exhibits good dynamics during starting and sudden load operations.
Practical implications
The presented method is simple, and implementation of it is easy. It is an eligible candidate for industrial applications where energy conversion efficiency is crucial.
Originality/value
The optimal turn-off angle definition that considers both torque production and copper loss minimization is proposed. The turn-on and turn-off angles are searched independently on-line with little SRM geometrical information. The searching steps are derived through analytical computation and qualitative analysis so that both the searching speed and algorithm convergence are balanced.
Details
Keywords
Fei Luo, Hai Jin, Xiaofei Liao and Qin Zhang
Peer‐to‐peer (P2P) communities have the capability to construct a powerful virtual supercomputer by assembling idle internet cycles. The purpose of this paper is to present the…
Abstract
Purpose
Peer‐to‐peer (P2P) communities have the capability to construct a powerful virtual supercomputer by assembling idle internet cycles. The purpose of this paper is to present the scheduling issues in an unstructured P2P‐based high performance computing (HPC) system to achieve high performance for applications.
Design/methodology/approach
A new application model is proposed for the system, where applications are parallelized in the program level. To address high performance for these applications, the system resources are controlled in a semi‐centralized 3‐layer network, where volunteers form many autonomous unstructured P2P domains. Furthermore, based on such a resource management policy, a job scheduling strategy is adopted, which is collaborated by global and domain scheduling. The global scheduling is responsible for the balance among domains, while the domain scheduling resolve workpiles' execution in a domain.
Findings
Theoretical analysis and a benchmark experiment show that the scheduling provides scalable and enormous computing capability in the P2P‐based HPC system.
Originality/value
The paper shows that scheduling helps P2HP (an unstructured P2P‐based HPC system) provide scalable and enormous computing capability for HPC applications.
Details
Keywords
Rafiu King Raji, Ning Li, Guiqiang Diao, Qin Luo and Hai Jin Liu
The purpose of this research is to ascertain the feasibility of fabricating polymer optical fibers (POFs) based textile structures by knitting with Polymethylmethacrylate (PMMA…
Abstract
Purpose
The purpose of this research is to ascertain the feasibility of fabricating polymer optical fibers (POFs) based textile structures by knitting with Polymethylmethacrylate (PMMA) based optical fibers for textile sensor application. It has long been established that by using the principles of physics, POFs have the capability to function as sensors, detecting strain, temperature and other variables. However, POF applications such as strain and pressure sensing using knitting techniques has since not been very successful due to a number of reasons. Commercially available PMMA-based optical fibers tend to be fragile and susceptible to breakages when subjected to stress during the knitting processes. Also light transmitted within these fibers is prone to leakage due to the curvature that results when optical fibers are interlaced or interlooped within fabric structures.
Design/methodology/approach
Using Stoll’s multi-gauge CMS 350 HP knitting machine, five fabric structures namely, 1 × 4 float knit structure, tunnel inlay knit structure, 3:1 fleece fabric and 2:1 fleece fabric structure respectively were used to knit sensor samples. The samples were subsequently tested for length of illumination and sensitivity relative to applied pressure.
Findings
The results of this preliminary study establish that embedding plastic optical fibers into a knitted structure during the fabric formation process for soft strain sensor application possible. The best illumination performance was recorded for tunnel inlay structure which had an average of 94 cm course length of POF being illuminated. Sensor sensitivity experiments also establish that the relative spectral intensity of the fiber is sensitive to both light and pressure. Problems encountered and recommendations for further research have also been discussed and proffered.
Research limitations/implications
Due to resource limitations, an innovative technique (use of precision weight set) was used to apply pressure to the sensors. Consequently, information regarding the extent of corresponding sensor deformation has not been used in this initial analysis.
Practical implications
Because the fundamental step toward finding a solution to any engineering problem is the acquisition of reliable data, and considering the fact that most of the popular technologies used for soft textile sensors are still bedeviled with the problem of signal instability and noise, the success of this application thus has the tendency to promote the wide spread adoption of POF sensors for smart apparel applications.
Originality/value
As far as research on soft strain sensors is concerned, to the best of the authors’ knowledge, this is the first study to have attempted to knit deformable sensors using commercially available POFs.
Details
Keywords
Jin-Hai He, Yu-Tao Pang, Xinzhi Dang and Wan-Cheng Yuan
The purpose of the study is to investigate and reveal this relationship of various engineering demand parameters (EDPs) of this structural type and intensity measures (IMs) under…
Abstract
Purpose
The purpose of the study is to investigate and reveal this relationship of various engineering demand parameters (EDPs) of this structural type and intensity measures (IMs) under intra-plate earthquakes.
Design/methodology/approach
The nonlinear finite element model used was calibrated first to the existing results of the shaking table test to verify the modeling technique.
Findings
This paper investigated the relationship between intensity measures and various engineering demand parameters of cable-stayed bridges using intra-plate earthquakes. The correlation analysis and Pearson coefficient are used to study the correlation between EDPs and IMs. The results showed that peak ground velocity (PGV)/peak ground acceleration, peak ground displacement and root-mean-square of displacement showed weak correlation with IMs. PGV, sustained maximum velocity, a peak value of spectral velocity, A95 parameter, Housner intensity and spectral acceleration at the fundamental period, the spectral velocity at the fundamental period and spectral displacement at the fundamental period were determined to be better predictors for various EDPs.
Originality/value
This paper investigated the correlation between the intensity measures of intra-plate earthquakes with the seismic responses of a typical long-span cable-stayed bridge in China. The nonlinear finite element model used was calibrated to the existing results of the shaking table test to verify the modeling technique. In total, 104 selected ground motions were applied to the calibrated model, and the responses of various components of the bridge were obtained. This study proposed PGV as the optimal IM.
Details
Keywords
This empirical study conceptualizes the institutional environment within which firms function in a transition economy as a number of dimensions, representing the externally set…
Abstract
This empirical study conceptualizes the institutional environment within which firms function in a transition economy as a number of dimensions, representing the externally set ‘rules of the game’ as perceived by senior managers. It then proposes a mediating model of the links between that environment and the commercial performance of enterprises in which incentive intensity is a key strategic choice, influenced by perceptions of the institutional setting and the influence of that choice is carried on to commercial performance by a set of managerial orientations. The model is tested using survey data from a sample of 959 Chinese enterprises.