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A numerical study was carried out on the electrostatic sticking of a charged paper to photoreceptor in electrostatic transfer process for electrophotography. Numerical procedures to predict sticking of the paper were presented which consists of (1) determination of initial angle of the paper, (2) estimation of electric field intensity, (3) estimation of charge on paper created by Paschen's air breakdown, (4) estimation of electrostatic force acting on the paper and (5) calculation of deformation of paper. Deformation of the charged paper in electric field was numerically simulated according to the procedures and the dependencies of paper sticking on photoreceptor size and initial angle of paper were quantitatively clarified. It is clarified that the smaller and softer photoreceptor improves sticking of paper.

The power transmission tower’s ground electrode defect will affect its normal current dispersion function and threaten the power system’s safe and stable operation and even personal safety. Aiming at the problem that the buried grounding grid is difficult to be detected, this paper proposes a method for identifying the ground electrode defects of transmission towers based on single-side multi-point excited ultrasonic guided waves. The geometric model, ultrasonic excitation model, and physical model are established, and the feasibility of ultrasonic guided wave detection is verified through the simulation and experiment. In actual inspection, it is equally important to determine the specific location of the defect. Therefore, a multi-point excitation method is proposed to determine the defect’s actual position by combining the ultrasonic guided wave signals at different excitation positions. Besides, the precise quantification of flat steel grounding electrode defects is achieved through the feature extraction-neural network method. Field test results show that, compared with the commercial double-sided excitation transducer, the single-sided excitation transducer proposed in this paper has a lower defect quantization error in defect quantification. The average quantization error is reduced by approximately 76%.

The aim of this paper is to present the impact of the leakage flux on magnetic shunts and tank walls of power transformers from vibrational point of view. The experimental studies of the large power transformers show that tank vibrations and the resulting acoustic emission at load condition are significantly higher than at no-load condition. The paper presents 3D finite elements model in electromagnetic domain used for the analysis of magnetic forces applied to shunts at rated short circuit state which are the origin of tank vibration. The main finding of the work is that forces equivalent to the magnetostriction deformation of the shunt interior are comparable with magnetic forces resulting from the stray field and applied to the shunts’ surface.

An experimental study was undertaken to evaluate the mathematical modelling of the magnetorheological (MR) damper featuring annular radial gap on its valve. The experiment was conducted using a fatigue dynamic test machine under particular excitation frequency and amplitude to get force-velocity and force-displament characteristics. Meanwhile, the mathematical modelling was done using quasi-steady modelling approach. Simulation using adaptive neuro fuzzy inference (ANFIS) Algorithm (Gaussian and Generalized Bell) were also carried out to portray the damping force-displacement modelling that is used to compare with the experimental results. The experimental characteristics show that amplitudes excitation and current input affect the result damping force value. The comparison of the experimental and mathematical results presented in this paper shows a significant difference in damping force value and that the quasi-steady modelling could not significantly approach the damping force-velocity results. Moreover, the semi-active damper is compared to the passive damper. The results show that a semi-active damper performs better than a passive damper because it only requires a little power. Based on the damping force-displacement modelling, it can be seen that Gaussian has a higher accuracy rather than Generalized Bell. Discussion on the energy dissipation and equivalent damping coefficient were also accomodated in this paper. Having completed in mathematical modelling and simulation, the damper would be ready for further work in-vehicle application that is development of control system.

This paper presents the cogging torque calculation in radial-flux surface-mounted permanent-magnet machines based on energy approach, air-gap flux density and permeance functions. Magnet segmentation and teeth notching are two important techniques in reducing the cogging torque, so in this paper an analytical approach is investigated to model these effects on the produced cogging torque. This approach employs new methods to model the teeth notch and PM segments based on Fourier expansion and simplified flux distribution. The analysis results and comparisons verify the validity of the model that has advantages in sensitivity analysis and structure optimizations of surface-mounted permanent-magnet machines from the aspect of cogging torque. This model could be extended for other types of PM electrical machines.

This paper presents a novel method for solving multi-objective optimization problems based on single-objective cellular genetic algorithm. In the proposed multi-objective cellular genetic algorithm, the objectives are divided into the primary objective and the secondary objective according to the preferences of a decision maker. The primary objective is used as the driving force for individual updating, while the secondary objective is employed as the bias force to select neighbors. The proposed approach has ensured that the secondary objective is also evolving in the optimal direction, as evidenced by the numerical results on both a mathematical test function and a prototype metamaterial unit as reported in this paper.

This paper introduces an axial-flux self-bearing motor (ASBM) using two permanent magnet attractive type passive magnetic bearings (PMBs). The ASBM provides both functions of a disc motor and thrust magnetic bearing, and controls motor torque and axial force by single rotational magnetic flux. The PMB consists of a cylindrical permanent magnet and an iron shaft with conical edge, and it supports the rotor in radial directions. This motor has a simple structure and control system, and it is possible to reduce the size and cost. In this paper, the structure and control method are introduced, and the results of levitation and rotation tests whose non-contact rotation speed was achieved up to 1,500 rpm are shown.

This paper presents a new methodology to calculate eddy current losses and Lorentz forces in foil winding transformers. This methodology is based on the equivalent winding current distribution in the foil winding and the iron core obtained by means of the Semianalytic Integral Method (SAIM) [1]. The main advantage of the calculation technique presented in this paper is that it is based on mathematical expressions which are compact and easy to evaluate, thus achieving a considerablereduction in the overall time required to determine the design parameters of the transformer. The results obtained from the proposed formulation have been compared to those obtained using the finite element method (FEM) using as a case study a 10 MVA transformer and an excellent agreement between both techniques has been obtained. Fil: Díaz Flórez, Guillermo A.. Universidad de La Salle; Colombia Fil: Mombello, Enrique Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Energía Eléctrica. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; Argentina Fil: Voss, Stephan. Siemens A.G.; Alemania

This paper presented a coupled electromechanical model and numerical method to obtain the torque response in a gas turbine rotor through transient analysis. Firstly, the FE model of the rotor based on beam elements and the electrical model of the generator were established. Then a contact element was introduced in the FE model to consider the contact effect between discs of the gas turbine rotor. The 4th Runge-Kutta method and Newmark method were used to solve the coupled equations iteratively to obtain the numerical solution of the transient response. Finally, a case study was presented and the results show much differences with those obtained through the conventional uncoupled analysis. The method and results of this paper are important to the rotor dynamic analysis and design of the gas turbine rotor in engineering.

Constant-force behavior is an unique property of superelastic NiTi shape memory alloy (SMA) and could be used in designing constant-force elements in surgical devices. It is easily obtained by stretching an SMA wire. However, studies with SMA bending strips have seldom been reported before. According to the constant-force design principles of the bending strips obtained through simulations in previous paper, several prototypes were developed for experimental evaluation. This paper presents a proof of concept on the principles through experiments. The results show its availability as constant-force element for practical use.

In this paper, the gyrotropic bi-anisotropy of the chiral medium in substrate constitutive parameters (ξc and ηc )o f a rectangular microstrip patch antenna is introduced in order to observe its effects on the complex resonant frequency, half-power bandwidth and input impedance. Numerical calculations and analysis based on the dominant mode are carried out to show that the latter is directly related to the former. This paper is based on the Moment Method as full-wave spectral domain approach using sinusoidal basis functions. Two new results, namely the appearance of the difference (ξc − ηc )a nd sum (ξc + ηc )o f the two magneto-electric elements are obtained in the electric transverse components and Green tensor expressions, respectively. These new results can be considered as a generalisation form of the previously published work.

This paper presents the overview of previous studies on the eddy current testing of Carbon Fiber Reinforced Plastic (CFRP) composites. CFRP is composed of many unidirectional carbon fiber/epoxy plies stacked together, thus it has laminated structure and inhomogeneous nature. Eddy Current Testing (ECT) is an efficient and non-contact Nondestructive Testing (NDT) technique for conductive materials. The electrical conductivity of carbon fibers can be utilized by ECT system for fiber texture mapping and detection of defects that can cause the conductivity change. Recently a lot of attention has been paid to the electromagnetic properties characterization of CFRP material, fiber texture and defect detection, as well as the ECT technique enhancement. In this paper we will give the detailed information and results of these research works. In addition this paper also summarizes the available numerical simulation methods for the electromagnetic modeling of CFRP materials, and the calculation of eddy currents and ECT signals.

Design and analysis of a shaped-beam 12.2 GHz array-fed reflector antenna for broadcasting satellite application and its significant performance improvement are presented in this paper. In the beginning, an elementary design employing a cluster of feed horns illuminating a single reflector has been proposed for multi beam antenna (MBA) system to produce contoured beam for Peninsular Malaysia. In this configuration, the horn positions were determined precisely through a newly developed caustic locus graph, which is the simplified technique for calculating the exact feed locations in both elevation and azimuth plane. The accuracy of the two-dimensional caustic locus graph, which was developed based on a ray tracing approach, has been verified through EM simulations. A universal feed position equation, derived from the technique has been very useful in designing the multiple feed structures employed in this research to ensure optimum radiation to the exact locations on the earth. Based on the initial design (a cluster of feed horns) due to the small size of the coverage area, an issue with regards to physical constructability of the feed horns is raised. To solve this problem, the MBA is modified by utilizing 18-element microstrip array as the feed, where each element positions are calculated by using the same caustic model. In this approach, calculations of accurate feed positions and optimum excitation coefficients in widely distributed feed areas are considered as among the most critical aspects in designing the shaped-beam antenna system. By using the proposed solution, the preceding issue is solved and higher gain shaped-beam coverage with optimized radiation pattern is generated. This paper shows the results of the contoured beam antenna that have been achieved for beam scanned over a small coverage size of approximately 0.9° long and 0.5°wide. Small variation of radiation level, which is less than 3 dB within the EOC, is also demonstrated in the performance analysis.

In electric power steering (EPS), spoke type brushless ac (BLAC) motors offer distinct advantages over other electric motor types in terms of torque smoothness, reliability and efficiency. This paper deals with the shape optimization of spoke type BLAC motor, in order to minimization cogging torque. In this paper examines, 3 step skewing rotor angle, optimizing rotor core edge and rotor overlap length for minimize cogging torque in spoke type BLAC motor. The methods were applied to existing machine designs and their performance was calculated using finite- element analysis (FEA). Prototypes of the machine designs were constructed and experimental results obtained. It is shown that the FEA predicted the cogging torque to be nearly reduce using those method.

There has been a 1000 kV ultra-high-voltage (UHV) AC transmission line running in China, but the related papers introducing the approach path of the helicopter live-line work platform (HLLWP) are still not presented. The model of the HLLWP approaching the transmission lines were established in this paper, based on the real parameters of helicopter MD500 and 1000 kV UHV AC transmission lines. Through calculating electrostatic field with the finite element method, the results of the electric field were obtained when the HLLWP was at different locations nearby a certain phase and approaching different phases. The surface electric fields on the HLLWP and operator’s conductive clothing at different locations were analyzed and then the optimal approaching paths of different phases based on the consideration of the HLLWP and operator’s safety were proposed to provide suggestions for the operations of the HLLWP. In the end, the experimental data was compared with the numerical result to prove the reliability of this method.

The paper presents a hybrid excited synchronous generator (HESG) with field windings and permanent magnets. This paper focuses on the analysis in the operating principle, rotor shape optimization, and inductance characteristic, based on finite element method. The measured voltage waveforms suggest that the rotor shape optimization in the study is a feasible solution to improve the quality of output voltage. Both the simulation and the tested results on generator performance verify further that the electric excitation can efficiently adjust the air-gap flux. Compared to conventional electric excited synchronous generator, the load capacity is improved due to relatively low armature inductance of the HESG.

This paper considers the pull-in of electromagnetic actuator with permanent magnet for the first time. The pull-in mechanism of electromagnetic actuator is explained from the perspective of system stiffness. Pull-in is about to occur when system stiffness becomes null. Based on the system stiffness analysis method, the pull-in parameters of an E-core electromag- netic actuator with permanent magnet are derived. Then, the effects of the permanent magnet on the derived pull-in parameters are studied. The analysis results show that the permanent magnet enlarges the pull-in displacement for its reluctance. If the permanent magnet length is more than three times as large as the initial displacement, pull-in would not occur. The effects of the permanent magnet on the pull-in current are complicated, especially the effects of the permanent magnet length. A method based on analyzing the roots of two properly defined equations is introduced to study the effects of the permanent magnet length on the pull-in current. The method is effective and simplifies the complicated analysis. Finally, numerical simulations are presented to validate the pull-in model and analysis methods in this paper. It is shown that the theoretical results are in a good agreement with the simulation results.

Most important journal papers in magnetics are selected from conference records with quick review and subject to stringent page limits. The literature as a result is unsatisfactory, inadequately attributing previous works and without sufficient details to replicate work presented. This paper therefore reviews mathematical optimization in synthesis and nondestructive evaluation (NDE) by the finite element method in magnetics. The review identifies the earliest papers. Thereafter this paper proposes and establishes the feasibility of coupled problem optimization using the genetic algorithm to avoid mesh induced minima which hurt gradient based methods. The genetic algorithm, while avoiding the need for derivatives, results in having to undertake even more numerous finite element solutions. Although the genetic algorithm has been applied in optimization, in coupled systems the number of object function evaluations doubles. We there examine the use of graphics processing units (GPUs) to handle the immense computational load. GPUs have recently been introduced in finite element analysis but their memory limits are often not recognized and are critically limiting when parallelizing the several solutions required in optimization. To overcome this limit, element-by-element finite element matrix processing is employed, making coupled problems practicable on GPUs. We overcome the memory limits faced by others.

Most of the electrical machines designed to have their stators on the outside and their rotors on the inside. However, it was noticed that the shaft fills a relatively high volume inside the machine without producing any torque. That means there is a wasted volume within the machine and this volume does not produce any torque. From this point of view, there are some trends in designing and building electrical machines to have their rotors outside the machine and their stators inside the machine. Here the example used for the machines using those designs is the permanent magnet (PM) machine, which is an electrical machines designed by the two different methods, inner and outer rotors to be used in many applications such as wind turbines and electric vehicle wheel motors. This paper is dedicated to prove that the external rotor permanent magnet machine is preferred for some significant reasons. The paper uses two approaches to demonstrate that. The first approach is using the geometrical volume of each machine to compare the torque capabilities in case of two possible topologies of the PM machines. The second approach is to compare the PM machine with another type of electrical machine, that has the same magnetic circuit topology and the rotor can be inside and outside as well.

The severe drawback of slotted permanent magnet linear synchronous motor (PMLSM) is the detent force, partic- ularly when accurate positioning and constant low speed is required for numerically controlled machine tool. In this paper, a novel short-armature slotted type multi-segment permanent magnet linear synchronous motor (MSPMLSM) is proposed and constructed to reduce the detent force. It consists of a proper shift of the multiple segments of iron core relative to the PMs. The detent forces of MSPMLSMs with different number of segment are analyzed and simulated by finite element method (FEM). The proposed structure has been proved to be a very effective approach for the reduction of detent force. Then this paper presents the statistical and mathematical optimum design of a 3-segment PMLSM using response surface methodology (RSM) together with FEM to minimize the detent force. Full factorial design and steepest ascent method, one of the iterative search method, is proposed to establish optimal design area for applying RSM. Finally, the global optimal design is predicted and the optimally designed one is manufactured, and the numerical results and measured results are reported to validate the effectiveness of this proposed method.

In this paper, a precise approach is proposed to detect DE in induction motors under unbalanced voltages. To achieve this goal, one essential problem is dealt with: The frequencies of the components caused by the DE in the stator current spectrum are similar to some of the frequencies introduced by the unbalanced voltages. Thus, the present paper attempts to explain, analytically, experimentally and by simulation, the generation process of all frequency components that are a function of the unbalanced voltages and the DE. For that reason, a detailed analytical study for three-phase induction motor working with DE is performed. First, an analytical expression for the mutual inductances between stator phases and rotor loops under DE is derived using mixture of winding function and Fourier series approach. Then, both theoretical and simulation studies are presented in order to show how the stator current is influenced by the simultaneous presence of DE eccentricity and unbalance supply voltages. Finally, experimental results have been presented to validate the analytical and simulation results.

This paper presents a novel piezoelectric harvester to convert ambient vibrations into usable electrical energy. Unlike the normal cantilever beam structure, the piezoelectric harvester developed in this paper is based on the wafer-stack config- uration, which is appropriated for large force vibrations. Firstly, two electromechanical models (without and with a rectifier circuit), considering both the mechanical and electrical factors of the harvester, were built to characterize the harvested electri- cal power across the external load. Exact closed-form expressions of the electromechanical models have been given to analyze the maximum harvested power and the optimal resistance. It was shown that the harvested electrical power depends on the external vibration characteristics, the natural frequency, the mechanical damping factor, the normalized electrical load, the stiff- ness of the harvester and the overall electromechanical coupling coefficient of the harvester. Finally, a shake table experimental testing was conducted to evaluate the feasibility of the proposed piezoelectric wafer-stack harvester under standard sinusoidal loadings. Experimental results show that the harvester can generate a maximum 16 mW DC electrical power for sinusoidal loading with 3040 N amplitude and 2 Hz frequency, and the harvested electrical power is proportional to the strength of the exciting vibration.

The important research area associated with the Ultra-Sonic Motor (USM) is the contact problem between the stator and the rotor. Because the USM operates by the friction force between the rotor and the stator, the contact problem of the USM have to be taken into account to analyze the motor performance accurately. Consequently, various types of the analysis methods have been proposed based on a contact model which describes the complex nonlinear contact condition of the USM. In this paper, diverse types of contact analysis methods for a Travelling Wave Ultra-Sonic Motor (TWUSM) are clearly condensed and precisely examined. The governing equations for the analysis of the TWUSM performance are derived through a precise investigation of the relationship between the contact condition and the motor performance in this paper. Furthermore, the motor performance is analyzed using contact models and the calculated data are compared with the experimental results.

According to the lift-off effect of eddy current testing, a ferromagnetic absorbing coating thickness gauge was proposed in this paper. After comparison, hyperbolic regression model was adopted to estimate the relationship between the detecting coil impedance and the absorbing coating thickness. An efficient probe with high quality factor and temperature compensation was developed. At the same time, a novel and more flexible calibration method was designed in this paper to improve the measurement accuracy. The experimental results show that the thickness measurement error is less than 0.02 mm, which proves the validity of this absorbing coating thickness gauge.

This paper describes 2 types of 2 DOF magnetic suspension systems which suspend two iron balls or an iron stick type object. Both suspension system controls 2 DOF of suspended object(s). The magnetic suspension forces are controlled by a generator of magnetomotive force. This suspension system must control two degrees of freedom without mechanical contacts. In iron stick suspension system, a vertical displacement and a horizontal rotation of the object should be controlled. This paper proves the feasibility of these noncontact suspension systems. A theoretical analysis will be done on the model of these suspension systems and numerical simulations carried out for confirmation of performances.

In this paper the mechanical deflection of steel bars, of different length, in a flux focusing magnetic gear is studied. The mechanical deflection is caused by the magnetic attraction between the steel bars and the inner and outer rotor magnets of the magnetic gear. An iterative magnetomechanical approach using commercial finite element analysis software has been adopted. Two different diameter magnetic gear models with different axial lengths have been modeled and the deflection has been calculated for each model. Experimental verification for one model is also shown. The paper shows that when operating with a small air-gap and long axial length the mechanical deflection can become significant.

This paper discusses high frequency acoustic noise generated by an IH cooker. Mechanism of the high frequency acoustic noise generation is clarified by experimental study. Recently, influence of the electromagnetic wave on the human body is worried. They symptoms some users of home electronic appliances feel are headache and nausea. There is a report that other users who are using IH cooking heater also feel these symptoms. We have discovered that the high frequency acoustic noise, which is generated from an IH cooker, indicates strong-level sound pressure. High frequency strong acoustic noise must not be ignored, because its danger on our health is reported scientifically and medical standpoints. Then, it becomes necessary to examine the suppressing method of high frequency acoustic noise. In this paper, generating mechanism of the high frequency (20 kHz∼) acoustic noise is clarified by the experiments.

This paper presents a new eddy current modeling approach in which the edge field contribution for a finite width conducting plate is accounted for. The 3-D steady-state analytic eddy current model accounts for the source field contributions from oscillatory as well as translational velocity motional effects. The paper discusses the modeling inaccuracies caused by neglecting the source field contributions on the edges of the conductive plate. The new modeling approach is validated by comparing the analytic calculations with a 3-D steady-state finite element analysis model.

This paper compares the power loss and weight of multiobjective optimal (MO) designed isolated DC-DC power converters based on Si and SiC technologies. To that end, a computer-aided design (CAD) tool previously published by the authors and dedicated to the MO design of isolated DC-DC power converters with genetic algorithms is used. The design problem requires the minimization of the power loss and the weight of the converter while ensuring the satisfaction of several constraints. The results show clearly that the wide band gap (WBG) semiconductor devices, typically the SiC technology for the power and voltage levels considered in this paper, lead to lighter converter with less power loss than classical Si devices. The use of our tool allows to precisely quantify that gain within a multiobjective optimization framework.

This paper deals with the dynamic analysis for the calculation of the support forces in a rotating elastic rod when subjected to simple types of axial forces. For simplicity the model starts with a linear straight spring and a lumped mass and expands into a distributed system. The analysis shows a shift in the natural frequency of the support forces, due to rotation and additional axial oscillations, these are highly influenced by both the axial and the shear forces, which are induced by the centripetal and Coriolis forces, respectively. Based on this finding, the paper shows that it is not possible to take advantage of the inertial forces and create long-term inertial thrust, even if the rotation is synchronized with the shifted natural frequency. The discussion includes extensions into the electromagnetic realm by comparing the mechanical system with its electrical equivalent.

In this paper, for the very first time, four corners truncated triple band square patch antenna loaded with Split ring resonator (SRR) structure has been reported. Based on truncated square patch antenna, it has a double split square ring resonant structure embedded in the center of the substrate of the square patch antenna. The resonant structure has a strong electric response in a certain frequency of interest, and can be used to construct metamaterial. The antenna is designed to function in triple bands in the frequency range of 0.5-2.0 GHz. The comparison of the metamaterial design with the conventional dielectric material design is also shown in the paper. Design results are obtained by a High Frequency Structure Simulator which is used for simulating microwave passive components.

In this paper, a 3D numerical simulation method was put forward by coupling magnetic-structural fields, and its reliability was verified through comparing with the experimental data offered by Suzuki. According to the characteristics of electromagnetic expansion of metal tube, this simulation method was used to analyze the uniformity of tube expansion when the length of tube was less than that of the coil. Meanwhile, a curve of homogeneity of electromagnetic tube expansion with different aspect ratios (ratio of length to diameter) of tube was given based on the criterion of uniformity on deformation at the condition of specific parameters presented in this paper. By analyzing the mechanical characteristics of tube expansion, a length range of tube was found where the tube deformed uniformly. The results derived from this paper provided a good guidance for optimization design of electromagnetic ring expansion experiments which will be conducted on and this could ultimately promote the application of electromagnetic forming.

In this paper, a novel control scheme of PID type internal model control (PID-IMC) using neural network (NN) is proposed for the position control of ultrasonic motor (USM). In the proposed scheme, a new NN controller combined with particle swarm optimization (PSO) based on probability is introduced. The NN controller is employed for tuning the control parameter in PID-IMC for compensating the characteristic changes and non-linearity in USM. On one hand, the application of the proposed method avoids the Jacobian estimation in conventional back-propagation (BP) type NN. On the other hand, the PSO based on probability, originated from tribes-PSO, simplifies the PSO setting by reducing the parameters to be set in USM control. For confirming the effectiveness of the proposed method in position control, a group of experiments have been done on an existent USM servo system and the results are studied in this paper.

Various technologies have ever been developed to minimize the detent force of linear motors. Although the traditional modular structure can effectively reduce the detent force, the width of the flux barrier and the number of units severely limit its application. To solve these, this paper proposes a new modular type of tubular permanent magnet synchronous linear motor (TPMSLM), which consists of two identical unit motors. For simplification, a subdomain analytical method of the unit motor is firstly established, and its accuracy is verified by a comparison with that of the finite element method. Using the two approaches, the important parameters of the motor are analyzed. A modified two-unit modular TPMSLM is also proposed through the star vectograms of the electromotive force, which achieves thrust performance similar to the traditional three-unit modular TPMSLM with a smaller axial size. Moreover, to make full use of the volume of the flux barrier, end teeth are added at both ends of the unit motors. The simulation results indicate that a reasonable end tooth structure can not only reduce the magnetic leakage phenomenon of the end but also effectively improve the thrust of the motor.

This paper discusses the impact of the adjacent channels on the 1-dB compression point, the IP3 and the IP5 of Radio Frequency (RF) amplifier by n-tone test. By combining the theoretical derivation and software simulation, the model analysis for the third/five order polynomial nonlinear amplifier has been achieved. Moreover, the control variable method is adopted to draw the curves for the input/output signals. The research shows that the 1-dB compression point, the IP3 and the IP5 drop as n increases, and they all have symmetry for a given n. The fifth-order polynomial nonlinear amplifier model is proposed, the research shows that the adjacent channels have a great impact on the 1-dB compression point, the IP3 and the IP5 of the desired channel. This effect must be taken into account in actual RF amplifier designs and wireless communication architectures.

Ships made of ferromagnetic metals interfere with Earth's magnetic field in their surrounding. The disturbance of the magnetic field makes possible localization and even identification of the ship, which could determine a threat to the ship. The measurement of the magnetic field around the ship enables to determine its magnetic signature. The paper presents a multidipoles model of the ship magnetic field, which allows to determine parameters of the ship magnetic signature. The ship built of ferromagnetic elements disrupts Earth's magneticfield in its surrounding. This disor- der is defined as the ship's own magnetic field. This field contains constant and induced components(2). Thecharacteristicfeaturesofthe ship'sownmagneticfield are called magnetic signature(2,4). Magnetic signature allows to specify the distribution of the magnetic field around the ship. Magnetic signature can be determined using numerical modeling or the measurement method (3). The numerical modeling of the ship's magnetic field with commercial software has limited capacity, because the thickness of ship's metal sheets is very small in comparison with its size (3). That makes it necessary to use a dense grid of a huge number of finite elements. Additionally, the existence of the ship's permanent magnetism complicates the numerical modeling. The paper proposes a new computational method for measuring anddeterminingthe magneticsignatureofa ship, whichis basedon measurementof themagneticfieldin selected points in space around the ship, and then on creating a model of the multidipoles magnetic field of the ship. In the multidipoles model of magneticfield, a certain numberof magnetic dipoles distributed in space inside the ship are assumed. Subsequently, the spatial distribution, the values and directions of the magnetic dipole moments are found using the optimization method. The multidipoles model allows to reconstruct the ship's multidipoles magnetic field distribution in the ship's surrounding (2,4). 2. The own ship's magnetic field Measurements of the ship magnetic flux density are carried out on the measuring range. In practice, the magnetic field distribution is measured along a certain trajectory around the ship at one depth. Due to the passive protection of the ship, knowledge of the distribution of the magnetic field across the lower half-spaceinthevicinity oftheshipisrequired. Thereforeoneneedsaneffectivemethodfordetermining

This paper deals with the optimum design focused on an LHS (Latin hypercube sampling) experiment with the many design variables of a developed motor and comparison of the optimum algorithm. The effective design variables are selected by screening and analysis of means (ANOM). In this paper, the optimum design is achieved by using the comparison response surface methodology (RSM) with the genetic algorithm (GA) method as the multiobjective optimum design. The torque ripple ratio is satisfied with a design goal within 3%. Therefore, multiobjective optimum design is considered between average torque and efficiency. The simulation results are compared with the experiment and show a deviation below 5%.

This paper presents the structure design and analysis of inner-rotor type axial-flux permanent magnet synchronous machines(AFPMs). The major sources of vibration in electric machines such as motors and generators are electric magnetic force distributed on both stators. The rotor suffers from unbalanced magnetic force when air gas are not symmetric on dual sides. In this paper, natural frequencies, mode shapes, and deformation were studied at normal and fault operations.

This paper presents a multi-material topology optimization for the design of permanent magnet synchronous motors (PMSMs). Specifically, structural shapes of permanent magnet (PM) and iron core in a PMSM rotor are simultaneously designed together with the orientation of PM magnetization. For a co-design of PM and iron core, relative permeability and residual magnetic flux density are interpolated by the three-field density approach based on the Helmholtz filtering and regularized Heaviside step function. Here, the Helmholtz filtering aims to attain smooth border in design results, and the Heaviside function enables us to acquire a clear border (i.e. zero-one design) without intermediate densities. The optimization goal is set as maximizing the average torque of PMSMs. The average torque is calculated by Maxwell stress tensor (MST) method considering a maximum torque per ampere (MTPA) control. To validate the effectiveness of the proposed multi-material topology optimization approach, a PMSM rotor with 4 poles and 12 slots is designed. In addition, design results at various settings of input current amplitude and PM strength are compared and discussed. When the input current is stronger than the PM strength, rotor PM and iron core are designed for utilizing both PM and reluctance torque components like V-shape interior PMSMs. On the other hand, in the case of stronger PM strength, PM is designed near the air-gap, which utilizes only PM torque component like surface PMSMs.

Crack orientation is a vital factor in the behavioral study of fractures, especially the study of crack propagation in structures that are under dynamic or fatigue loading. Indeed, many non-destructive testing (NDT) techniques have been developed recently for the detection of cracks such as the eddy current testing (ECT). However, the crack orientation has not been undertaken into consideration. In this paper, a NDT based on eddy current using 3D finite element modeling, is proposed for the determination of the crack orientation. The idea of this proposed technique benefits from the influences of crack orientation, which can be observed on the components of eddy current and the related magnetic flux density following the x, y axes, for the estimation of the crack angle orientation based on an interpolation criteria. The obtained results through the presented simulation prove the validity of the proposed technique for the detection of crack angle orientation.

This paper presents a new synchronized switch circuit for piezoelectric semi-active vibration control. Recently, Synchronized SwitchingDamping (SSD)controllershave been used to switchpiezoelectric materialsinorder to damp vibration. In contrary to standard active and passive piezoelectric damping, these switching shunt circuits allow a small implementation and require only little power and, moreover, they offer the advantage of self-adaptation with environmental variations and their broadband frequency efficiency. However, the control performance of previous SSD approaches relies on the electrical quality factor of the switch circuit. This paper presents a novel form of the SSD with a negative capacitance, which is to maintain the environmental adaptation and bypass the influence of the quality factor to the damping system. The expression of the vibration attenuation at the resonance frequency is derived, and the effectiveness of this new circuit design is demonstrated by comparing with SSDI and negative capacitance shunt passive control of a resonant cantilever composite beam with embedded piezoelectric patch. Theoretical predictions and experimental results show a remarkable attenuation on the vibration of cantilever beam, which excels the other two techniques.

The paper presents a physical structure optimizat ion of an integrated semiconductor device design: a power MOSFET and other vertical transistors are integrated within the same die, introducing a novel self supplied power transistor. This integrat ed optimal design leads to complex optimization problems with close constraints. The main constrain t deals with the avalanche phenomenon that is formulated by multiple integral expressions of nume rical functions. The paper focuses on two aspects: the integral formulation of the avalanche model and mor e specifically its gradient computation in the view of applying a gradient-based optimization algorithm, a nd the comparisons of several optimization methods on this problem. Keywords : Genetic optimization algorithms, gradient-based o ptimization algorithm, integration constraint, Power MOSFETs, design of monolithically integrated circuits.

This paper describes the development of a hand rehabilitation system for stroke patients. Our aim is to provide fine motion exercise for a hand and fingers. Thus, a hand rehabilitation device that assists patients' finger movements was developed. Because this device has 18 degrees of freedom of motion, it is diffcult for disabled patients to use it by themselves. Therefore, an appropriate control strategy and control system are required to allow its safe and effective use. In light of this requirement, a control system was constructed which is comprised of four separated controllers. This paper presents the structure of the control system and introduces the control protocols used in our hand rehabilitation system.

This paper analyzes pulse voltage operations of a two-to-four phase voltage-induction-type electrostatic motor (VITEM) to clarify the appropriate driving sequences. The paper also evaluates transient charge effects that can possibly enhance the thrust force. VITEM has been studied as a novel centimeter-sized electrostatic film motor whose power to the slider is supplied indirectly through its induction electrodes. Since a smooth synchronous driving was aimed in the past stud- ies, high-frequency AC voltages have been used for the driving. This paper demonstrates that straightforward usage of simple pulse sequences cannot realize continuous stepping driving, and proposes several different sets of modified pulse sequences to realize continuous stepping driving using low-switching-rate pulse voltages. In the experiments, the motor showed continuous stepwise driving with a step width of about half of the electrode pitch. In addition, transient characteristics of charges on films were evaluated experimentally under the pulse driving condition, and contribution for thrust force enhancement was clarified.

In this paper is presented an extensive theoretical study and some experimental results regarding an electromagnetic generator based on levitated magnet, designated to harvest energy from ambient vibrations. Generator optimization for achiev- ing the maximum values of transmissibility and electrical power was performed by considering a resonance frequency different from the natural frequency that is usually used in literature. The step response of the system, described analytically, is useful in the analysis of generators subject to sudden variations of the random vibration amplitude. The obtained experimental results indicate the possibilities of optimization and increase of the device power depending on the frequency and amplitude of external vibrations. The generator with levitated magnet studied in this paper, provided a maximum power of 27 mW when working as a quasi-linear oscillator and of 64 mW, respectively, when working as a non-linear oscillator.

Design and control of many electromagnetic actuators involve solving three dimensional (3D) magnetic fields of permanent magnets and/or electromagnets in the presence of magnetic conducting surfaces. This paper extends the distributed multipole (DMP) method, which offers compact but precise analysis for three dimensional magnetic fields in closed form, to account for the effects of magnetic conducting boundaries using the image method on the torque generated by electromagnetic actuators. We validate the proposed method referred to here as DMP-Image method by comparing the calculated torques against results computed by a finite element method (FEM). Wh ile two methods agree to within 5% in maximum torque, the DMP-image method takes less than 1% of the FEM computation time. Finally, we demonstrate the DMP-Image method to design a spherical motor in a class of multi-DOF actuators. While developed in the context of the multi-DOF actuators, the modeling methods presented in this paper are applicable to design of other PM-based actuators.

Electromagnetic welding (EMW) is a specific application of E lectromagnetic Forming (EMF), owing to the fact that the latter very often than not precedes the former, which means that the metallic parts to be welded get deformed before getting welded. This is a new application of electromagnetic field. This being so, there are not much efforts made for the electrical characterization of the equipment to improve it 's performance. The electrical parameter of the system are a nalyzed in detail in this paper for welding of aluminum strips of 1 mm and 2 mm thickness (width = 400 mm and length = 550 mm). The two bodies (to be welded) have necessarily to be separated from each other so that they acquire sufficient velocity bef ore collision. The collision velocity is the important paramet er in this process. The variation in collision velocity is co mputed for a range of separation distances. The optimum separation distance and minimum energy required for welding is computed and experimentally verified. The paper summarizes the analy sis comprising of computational work, substantiated by data for mechanical strength tests and the study of microstructure. The correlation between the quality of weld and collision velocity has been established.

This paper proposes a magnetic suspension system using a permanent magnet (PM) and a rotary actuator. In this suspension system, the suspension force is controlled by a variable magnetic flux path mechanism where the flux path is cha nged by varying the angle of the PM. The PM is magnetized in radial direction and driven by a rotary actuator. This system can change the magnetic polarity of the stator and generate a very small suspension force through rotating the PM to some special angles. Since the fixed cores sustain the gravitational forc e of the suspended object and the rotary actuator has a larger reducer, this system also can generate a very big suspension force comparing with the input force. In this paper, first the prototyp e and the principle of this magnetic suspension system are explained. And in order to verify the proposed principle, the IEM (integral element method) analysis and basic experiments for magnetic flux density and attractive force are performed. The model i s created, and the numerical simulation is carried out. Final ly, suspension experiments are executed, and the results support our proposal.

This paper presents measured iron loss properties of a rotating machine's stator core at each manufacturing stage. It is well known that the magnetic properties deteriorate in constructed cores due to stress in manufacturing process and the iron loss increases in comparison with one of the ideal material used in designing, and then the building factor becomes more than one. In this paper, knowledge obtained in development of a simplified evaluation method of iron losses in actual stator co res of rotating machines is presented.

This paper presents results of magnetic characteristic ana lysis of a magnetic flux concentration type surface magnet motor. Firstly influence of number of the rotor poles on the to rque characteristics was examined for fixed stator construc tion and then some constructions of the permanent magnet array were tested to reduce the cogging torque. Their magnetic flux distributions and torque characteristics were calculated by using the finite element method. Permanent magnets with strong magnetism are widely used in daily life. Especially, role of the permanent magnet material used in the motors is very important for our social life, because we can reduce input energy and improve efficiency by using the perma nent magnets. The magnetic energy of the permanent magnets is directly converted into the rotational force, without supplying current to generate the magnetic field of the field system such as the three-phase s ynchronous motors. Miniaturization of the motors utilizing the permanent magnets has being done with progress of the performance of the permanent magnet materials. Recently, technology to generate a strong magnetic filed ove r 4T in a local region by combining the NdFeB permanent magnets has been developed. As a result, it came to be able to obtain larger magnetic energy than that of the magnet pole's surface due to the resid ual magnetization. There is a possibility of a further characteristic improvement of the permanent magnet motors by using the powerful energy produced by combining the NdFeB permanent magnets. However, the applications of strong magnetic field to the permanent magnet motors are limited and a new appl ied technology has not progressed yet. In order to develop a small size and high power motor, higher magnetic flux density in the air gap needs to increase torque and power under a constant revolution speed. Concentration type permanent magnet arrangement is one of the effective solutions to generate high magnetic flux density as mentioned in the above. We have developed a new surface permanent magnet synchronous motor by using the concentrated permanent magnet arrangements. The same magnetic poles of the assembling permanent magnets on the rotor surface are faced to each other to generate larger magnetic flux density in the air gap. We call this the concentrated surface permanent magnet synchronous motor (CSPMSM). In this paper, the torque characteristics depending on magnet arrangements are numerically examined by using the finite element method (FEM).