Stator tooth shape optimization for double salient hybrid excitation generator based on asymmetric circuit analysis

2019 ◽  
Vol 38 (6) ◽  
pp. 1738-1755 ◽  
Author(s):  
Shuchun Yao ◽  
Wei Zhang
Keyword(s):  
Shape Optimization ◽  
Optimization Scheme ◽  
Voltage Fluctuation ◽  
Tooth Shape ◽  
Content Type ◽  
Dc Voltage ◽  
Excitation Generator ◽  
Finite Element Analysis Simulation ◽  
Hybrid Excitation ◽  
The Asymmetry

Purpose This paper aims to clarify the relationship between stator tooth shape and DC voltage fluctuation of a double salient hybrid excitation generator (DSHEG). It analyzes the asymmetrical characteristics of the magnetic circuit and inductance between each phase. The study aims to reduce voltage fluctuation by using a stator shape optimization scheme, which helps reducing inductance difference. Design/methodology/approach This paper opted for a method combined with theoretical analysis, simulation and experimental verification. The stator tooth optimization scheme is given based on theoretical asymmetrical analysis and Taguchi method. A series of two-dimensional finite element analysis simulation of different conditions are conducted. Two prototypes with different stator tooth shape are made and experiments are carried out. Findings The paper provides empirical insights into how the stator tooth shape influences the asymmetry of inductance and DC voltage fluctuation. Compensation adjustments to the stator tooth shape can narrow the inductance differences of each phase. It suggests that “LTL” shaped DSHEG has lower voltage ripple than “III” shaped DSHEG without sacrificing output power. Research limitations/implications Because of the chosen research approach, the gap between magnets and stator and end effect are not considered. Errors exist between simulation and experimental results. Practical implications The paper includes implications for other “C” shaped tooth optimization. Study on phase asymmetry of the special machine can further improve quality testing and simplify control strategy. Originality/value This paper analyzes the asymmetry of DSHEG and proposes an optimized stator tooth shape to reduce DC voltage fluctuation.

Adaptive response prediction for aerodynamic shape optimization

2017 ◽  
Vol 34 (5) ◽  
pp. 1485-1500
Author(s):  
Leifur Leifsson ◽  
Slawomir Koziel
Keyword(s):  
Shape Optimization ◽  
Adaptive Response ◽  
Simulation Models ◽  
Response Prediction ◽  
High Fidelity ◽  
High Fidelity Simulation ◽  
Aerodynamic Shape Optimization ◽  
Content Type ◽  
Aerodynamic Shape ◽  
Fidelity Model

Purpose The purpose of this paper is to reduce the overall computational time of aerodynamic shape optimization that involves accurate high-fidelity simulation models. Design/methodology/approach The proposed approach is based on the surrogate-based optimization paradigm. In particular, multi-fidelity surrogate models are used in the optimization process in place of the computationally expensive high-fidelity model. The multi-fidelity surrogate is constructed using physics-based low-fidelity models and a proper correction. This work introduces a novel correction methodology – referred to as the adaptive response prediction (ARP). The ARP technique corrects the low-fidelity model response, represented by the airfoil pressure distribution, through suitable horizontal and vertical adjustments. Findings Numerical investigations show the feasibility of solving real-world problems involving optimization of transonic airfoil shapes and accurate computational fluid dynamics simulation models of such surfaces. The results show that the proposed approach outperforms traditional surrogate-based approaches. Originality/value The proposed aerodynamic design optimization algorithm is novel and holistic. In particular, the ARP correction technique is original. The algorithm is useful for fast design of aerodynamic surfaces using high-fidelity simulation data in moderately sized search spaces, which is challenging using conventional methods because of excessive computational costs.

A new jig-shape optimization method for the high aspect ratio wing

2018 ◽  
Vol 91 (1) ◽  
pp. 124-133
Author(s):  
Zhe Yuan ◽  
Shihui Huo ◽  
Jianting Ren
Keyword(s):  
Aspect Ratio ◽  
Shape Optimization ◽  
High Aspect Ratio ◽  
Optimization Design ◽  
Design Method ◽  
Aircraft Design ◽  
Optimization Method ◽  
Attack Angle ◽  
Structural Deformation ◽  
Content Type

Purpose Computational efficiency is always the major concern in aircraft design. The purpose of this research is to investigate an efficient jig-shape optimization design method. A new jig-shape optimization method is presented in the current study and its application on the high aspect ratio wing is discussed. Design/methodology/approach First, the effects of bending and torsion on aerodynamic distribution were discussed. The effect of bending deformation was equivalent to the change of attack angle through a new equivalent method. The equivalent attack angle showed a linear dependence on the quadratic function of bending. Then, a new jig-shape optimization method taking integrated structural deformation into account was proposed. The method was realized by four substeps: object decomposition, optimization design, inversion and evaluation. Findings After the new jig-shape optimization design, both aerodynamic distribution and structural configuration have satisfactory results. Meanwhile, the method takes both bending and torsion deformation into account. Practical implications The new jig-shape optimization method can be well used for the high aspect ratio wing. Originality/value The new method is an innovation based on the traditional single parameter design method. It is suitable for engineering application.

Modeling and simulation analysis of the hybrid excitation synchronous machine system utilizing tooth harmonic for excitation

2016 ◽  
Vol 35 (2) ◽  
pp. 540-555 ◽  
Author(s):  
Yonghong Xia ◽  
Junbo Liu ◽  
Bo Xu ◽  
Hongjian Wu
Keyword(s):  
Permanent Magnet ◽  
Operation Mode ◽  
Structural Features ◽  
Current Waveform ◽  
Standard State ◽  
State Equations ◽  
Permanent Magnet Machine ◽  
Content Type ◽  
Machine System ◽  
Hybrid Excitation

Purpose – The purpose of this paper is to propose a novel hybrid excitation permanent magnet synchronous generator (HEPMSG) utilizing tooth harmonic for excitation, the structural features and operation principle of which are also described. Design/methodology/approach – To obtain the operation performance quickly, this paper derives the mathematical model of the machine system represented by circuit, and analyzes the operation mode of rectifier circuit in the tooth harmonic excitation system, then the standard state equations for each operation mode are obtained. Combining the inductance parameter of this machine with the load resistance and inductance, the armature current waveform, the field current waveform and tooth harmonic winding current waveform are obtained by using the numerical method to solve the standard state equation. Findings – Comparing with the experimental results, the availability of the principle and the validity of the model of the machine system are verified. Practical implications – This HEPMSG is a new brushless self-excited and self-regulated generator, which is suitable for an independent power source. Originality/value – Unlike the existing hybrid excitation permanent magnet machine, this HEPMSG utilized the inherent tooth harmonic EMF of the rotor to adjust the air-gap magnetic field of the permanent magnet machine.

Suppressing the Effects of DC Voltage Fluctuation in PWM Inverters by Using Virtual Impedance

2021 ◽  
Author(s):  
Tri Ardriani ◽  
Lukas Antonio Budiwicaksana ◽  
Adinda Ihsani Putri ◽  
Jihad Furqani ◽  
Arwindra Rizqiawan ◽  
...  
Keyword(s):  
Voltage Fluctuation ◽  
Dc Voltage ◽  
Virtual Impedance

A Simple Control Method of Output Voltage for Three-Phase Multilevel Inverter Considering the DC Voltage Fluctuation

2008 ◽  
Vol 128 (3) ◽  
pp. 244-250
Author(s):  
Kenji Amei ◽  
Kenji Teshima ◽  
Youhei Tanizaki ◽  
Takahisa Ohji ◽  
Masaaki Sakui
Keyword(s):  
Output Voltage ◽  
Control Method ◽  
Multilevel Inverter ◽  
Voltage Fluctuation ◽  
Dc Voltage ◽  
Three Phase

Normally Bypassed Cascaded Sources Multilevel Inverter with RGA Optimization for Reduced Output Distortion and Formulaic Passive Filter Design

2019 ◽  
Vol 29 (02) ◽  
pp. 2050019
Author(s):  
G. Chitrakala ◽  
N. Stalin ◽  
V. Mohan
Keyword(s):  
Distributed Generation ◽  
Single Phase ◽  
Filter Design ◽  
Circuit Complexity ◽  
Optimization Scheme ◽  
Dc Voltage ◽  
Multilevel Inverters ◽  
Harmonic Content ◽  
Lc Filter

The distributed generation involving multiple photovoltaic sources and synthesizing high-quality ac voltage from those multiple dc sources are nascent research ambits. A host of multilevel inverters (MLIs) has been ascertained for performing above errand diligently, where the component count is obnoxious. The single phase seven-level inverter is an acquiescent compromise between the circuit complexity and the quality of the output. Further enhancement on the performance can be succored through optimizing dc link voltages and switching angles. This paper proposes a component count pruned MLI structure and also a refined genetic algorithm (RGA)-based optimization scheme for the computation of both dc link voltages and switching angles. Previous attempts for this problem have solved the switching angles with the objective of resulting minimum harmonic content in the staircase-shaped output voltage. The dc link voltage of each level is however assumed to be the same and constant. As an extension, RGA-based optimization of both dc link voltages and switching angles is triumphed. The harmonic profile of the proposed switching strategy is simulated and also corroborated by a hardware prototype. In practice, the proposed fundamental switched strategy is apposite, in which each dc voltage can be self-maintained and independently controlled. In addition, a method for designing the passive LC filter is also presented.

scholarly journals How emerging market resource-poor firms compete and outcompete advanced country resource-rich rivals

2018 ◽  
Vol 25 (3) ◽  
pp. 538-544 ◽  
Author(s):  
Xin Li
Keyword(s):  
Emerging Market ◽  
Competitive Dynamics ◽  
Market Position ◽  
Market Segments ◽  
Advanced Country ◽  
Content Type ◽  
Product Categories ◽  
Resource Poor ◽  
Three Stages ◽  
The Asymmetry

Purpose The purpose of this paper is to comment on Professor Ming-Jer Chen’s recent publication titled “Competitive dynamics: Eastern roots, Western growth” and present an asymmetry reversing perspective on the competitive dynamics between two nonobvious, invisible or indirect competitors, namely, how emerging market resource-poor firms compete and outcompete advanced country resource-rich rivals. Design/methodology/approach The author first identifies an important neglect in Professor Chen’s scholarship on competitive dynamics, i.e., the neglect of the ubiquity of the less visible competition between two actors who initially would not be considered as competitors. Then, the author proposes an asymmetry reversing theory (ART) of competitive dynamics to redress this neglect. The theory is presented in two parts. The first part describes the competitive dynamics between the two actors as a three-stage process of reversing the asymmetry in resource possession and market position between the resource-poor firm and its resource-rich rivals. The second part explains the key success factors for the resource-poor firm to go through each of the three stages. Findings The growth process of the resource-poor firm can be broadly divided into three stages: surviving, catching-up, and outcompeting. For ambitious yet pragmatic resource-poor firms, in the surviving stage, they often (have to) accept the asymmetry between themselves and their resource-rich rivals in terms of resource possession and market position, and try to avoid any direct competition with the strong incumbents. They often tactically appear to pursue different paths of development from those of the strong incumbents by focusing on particular product categories and market segments. Doing so allows the resource-poor firms to win times and spaces for non-interrupted growth. Once they have accumulated sufficient resources and market experiences, they start to reduce the asymmetry between themselves and their better-endowed rivals by entering the similar or same product categories and market segments. To effectively catch up and outcompete the incumbents, they often differentiate themselves from their rivals by offering cheaper products or services, adding new features to their products, providing extra services to their customers, inventing new business models, etc. Research limitations/implications One limitation of this paper is that the ART framework has so far been built on anecdotal evidences. It needs to be tested by empirical studies and refined further in the future. Another limitation is that the proposed theory is based on competitive dynamics between emerging market resource-poor firms and advanced country resource-rich firms. It needs to be tested whether this theory has applicability to any other firms. Originality/value This paper fills an important research gap in the competitive dynamics literature by proposing an asymmetry reversing theory of competitive dynamics between a weak latecomer and a strong incumbent in a competitive field.

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