Modeling, analysis, and experimentation of chaos in a switched reluctance drive system

In this brief, modeling, analysis, and experimentation of chaos in a switched reluctance (SR) drive system using voltage pulsewidth modulation are presented. Based on the proposed nonlinear flux linkage model of the SR drive system, the computation time to evaluate the Poincaré map and its Jacobian matrix can be significantly shortened. Moreover, the stability analysis of the fundamental operation is conducted, leading to determine the stable parameter ranges and hence to avoid the occurrence of chaos. Both computer simulation and experimental measurement are given to verify the theoretical modeling and analysis.published_or_final_versio

Design of a new non-rare-earth magnetic variable gear for hybrid vehicular propulsion system

This study presents the design of a new non-rare-earth magnetic variable gear (MVG) with 16 electrically controlled gear ratios, which incorporates both the concept of the magnetic gear and the concept of the memory machine. The high-remanence low-coercivity permanent magnet material: namely, the aluminium–nickel–cobalt is adopted to realise the controllable gear ratios. The key is to design the stationary ring newly integrated with magnetising windings in such a way that 16 sets of gear ratios can be achieved so as to fulfil different driving requirements and road conditions. First, the original MVG, the improved MVG and the proposed MVG are discussed. Then, a comprehensive analysis of the proposed MVG is conducted. Consequently, the proposed MVG is extended to electronic-continuously variable transmission for hybrid vehicular propulsion. By using finite element analysis, the electromagnetic performances of three MVGs at various gear ratios are evaluated, hence validating the theoretical design. Moreover, the process of gear-ratio-changing is simulated and analysed. A quantitative comparison among these MVGs is also carried out. Hence, the corresponding validity can be further verified.postprin

Feeling entitled to more: Ostracism increases dishonest behavior

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Analysis of chaos in current-mode-controlled dc drive systems

In this paper, chaotic behavior in current-mode-controlled dc drive systems has been analyzed. The key is to derive an iterative map that describes the nonlinear system dynamics. Analytical modeling of fundamental and subharmonic oscillations as well as their stability analysis are presented. The results show that the current-mode-controlled dc drive systems generally exhibit chaotic behavior. To avoid the occurrence of chaos, the stable ranges of various system parameters are determined. Both computer simulation and experimental measurement are given to verify the theoretical analysis.published_or_final_versio

Dynamic bifurcation in dc drives

Dynamic bifurcation as well as chaotic behavior in a fixed-frequency current-mode controlled dc chopper-fed dc motor drive system is presented. The key is to derive an iterative map that describes the nonlinear dynamics of the system operating in the continuous conduction mode. It illustrates that different bifurcation diagrams can be obtained by varying different system parameters. Analytical modeling of period-1 and hence period-p orbits as well as their stability analysis using the characteristic multipliers are also presented. Hence, those stable ranges of various system parameters can be determined. Moreover, chaotic behavior is quantified by evaluating the Lyapunov exponents. The proposed approach is so general that it can readily be applied to other current-mode dc drives.published_or_final_versio

The Impact of a Structured Electronic Interacting Brainstorming Platform

SUMMARY: With the advancements in technology and the recent trends in how audit teams communicate, audit firms increasingly develop and rely on computer-mediated communications and online platforms in the conduct of audits. We examine the effects of two different electronic interacting brainstorming platforms, structured (idea inputs organized into trees and shown by categories/topics) and non-structured (idea inputs in chronological sequence), on audit team brainstorming performance. While the psychology literature suggests potential benefits from the structured brainstorming platforms, we find that, in a fraud hypothesis generation task, a structured brainstorming platform does not improve audit team fraud brainstorming performance (either quantity or quality of fraud hypotheses generated). Further, we find that a structured brainstorming platform reduces the differences in brainstorming performance and mental simulations between managers and seniors. This is because a structured brainstorming platform reduces managers’ performance, although it has no negative effects on seniors’ performance

Chaoization of switched reluctance motor drives

This paper presents a new technique for the chaoiztion of switched reluctance motor (SRM) drivers. Based on the chaotic modeling of SRM drives, effects of feedback controller gains on the stability of the rotor speed are investigated. In accordance, a control strategy combining piecewise proportional feedback and time-delayed feedback is proposed to produce bound-controllable oscillation around any specific rotor speed. To estimate the continuous influence of a certain control parameter, a Poincaré map sampling at every extreme points is constructed, then the bifurcation diagrams are drawn. Theoretical analysis and numerical simulation for a practical 12/8 motor driver are also given.published_or_final_versio

Subharmonics and chaos in switched reluctance motor drives

In this paper, the investigation of the nonlinear dynamics of an adjustable-speed switched reluctance motor (SRM) drive with voltage pulse width modulation (PWM) regulation is carried out. Nonlinear iterative mappings based on both nonlinear and approximately linear flux linkage models are derived, hence the corresponding subharmonic and chaotic behaviors are analyzed. Although both flux linkage models can produce similar results, the nonlinear one offers the merit of accuracy but with the sacrifice of computational time. Moreover, the bifurcation diagrams show that the system generally exhibits a period-doubling route to chaos.published_or_final_versio

A flexible AC distribution system device for a microgrid

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