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Cognitive radio networks are attracting a lot of interest in wireless research community and industries which allow flexible use of utilized spectrum. The dynamic use of available spectrum bands needs proper spectrum handoff mechanism for switching to different operating frequencies based on vacant channels. Therefore, blocking probability, switching or handoff delay, link maintenance and failure...
Hybrid excited flux-switching machine (HEFS) is a novel brushless synchronous motor. Compared to conventional permanent magnet synchronous machine (PMSM) and permanent magnet flux switching (PMFS) machine, it has additional excitation winding in its stator to modulate the air-gap magnet field. In this paper, the topology and operating principle of HEFS is analyzed. Its dynamic mathematical models...
A two-dimensional (2D) rotary axisymmetric model has been developed to describe the formation and development of cathode spot in vacuum arc. The model includes hydrodynamic equations and thermal conductivity equation. Parameters used in this model come from experiments and other researchers' work. The simulation results show that when the energy flux density is 1.5∼3×1012W, discharge current is 1∼6A...
The paper describes a 3D semi-analytical harmonic modeling technique, which is capable to model eddy current distributions in conducting structures and the associated fields. The induced current density and magnetic fields in the spectral domain are described, where a spatially varying conductivity of a conducting region is incorporated in the solutions of magnetic-field quantities. An experimental...
This paper presents an efficient method to measure physical parameters of thin elastic layers by using an air-coupled ultrasound technique. In the method, surface densities of elastic thin layers are approximated through solely non-contact measurement of through-transmission of ultrasonic signals. A copper foil and a copper foil coated with carbon composite on both sides are used to experimentally...
Adaptive control of an interior permanent magnet synchronous motor (IPMSM) has been proposed for compensation of parameter uncertainties. However, the control Lyapunov function (CLF) utilized in the method has a problem that the function is not a global one. In this research, we devise a global control law by using a global CLF designed with the multilayer minimum projection method. Moreover, we show...
This paper details a co-design and modelling methodology to optimise the flip-chip assembly parameters so that the overall package and system meets performance and reliability specifications for LED lighting applications. A co-design methodology is employed between device level modelling and package level modelling in order enhance the flow of information. As part of this methodology, coupled electrical,...
Highly dynamic DC-machines, used in low power applications, often contain ironless or so called bell shaped windings. Because there is no massive iron core to support the windings, one of the limiting factors for the torque of the machine is the force on the single wires of the copper weave. Therefore, the knowledge of the force distribution on the single wires could be a helpful design criterion...
Three-dimensional system integration with through-silicon-vias (TSVs) is regarded as a promising solution to the “More-than-Moore” challenge to improve the performance of micro- and nano-electronic devices. However, the copper extrusion of TSVs during the back-end-of-the-line (BEOL) process and under service conditions poses serious reliability concerns. Substantial experimental and simulation work...
A method of extracting the effective copper surface roughness of a laminate in situ is introduced. The rough copper attenuation, as a function of surface roughness, is removed from the total attenuation. The residual loss is fit to coefficients, and an error is calculated based on the remaining surface roughness contribution. When the error is minimized or when the apparent surface roughness contribution...
Different from permanent magnet synchronous machine, switched reluctance motor(SRM) is featured as high local flux density, high current variation ratio in the winding with medium, high power and high speed. Therefore, hot spots in the winding could be caused by eddy current effect. When current flows through winding, skin effect is generated by the high frequency alternating current due to the high...
In order to investigate the reliability of micro-interconnecting copper pillar bump under thermal-electric coupling, the test chip with electrified daisy chain copper pillar bumps was designed and manufactured. And 9 sets of thermoelectric coupling accelerated life test were carried out respectively, which the resistance increased by 10% was considered as the failure threshold to get the mean-time-to-failure...
This paper focuses on the loss analysis and optimized design of DC-DC converter for battery module. By using the data measured from the experiment study of inductor loss and component datasheets to derive the inductor, MOSFET, and capacitor loss equations of bidirectional buck converter, boost converter, and buck-boost converter through numerical analysis. In addition, the charging and discharging...
A three-dimensional mathematical modeling and an analysis of the magnetic and temperature fields distribution in a lined inductor of melting-holding furnace for copper melting have been made. The analysis has been made based on the following objects properties: a complex geometry of the system; a non-linear conductivity dependence on the copper temperature; ferromagnetic properties of the iron magnetic...
Finite Element simulations are often used to study the reliability of solder joints subjected to thermal cycling. Packaging configurations are becoming more complex to accommodate better functionality and performance. Increased complexity leads to several challenges for FE models including difficulties modeling thin layers and interfaces, as well as keeping the total numbers of nodes and elements...
This study was aimed at quantifying critically relevant topics about the influence of intermetallic compounds (IMC) within power electronics reliability such as the influence of soldering profile on the growth rate of IMC in large area solder joints, estimation of IMC thickness during non-isothermal ageing and the impact of IMC thickness on reliability. To this end, test samples were soldered using...
This paper proposes a method based on the quadratic programming (QP) sequence for solving loss-minimizing current, which yields minimum loss of motor, of control system for interior permanent magnet synchronous motor (IPMSM) of electric vehicle. First, the efficiency optimization of IPMSM is modeled as a constrained programming problem, and then transformed it into linear constraint QP sequence. The...
This article proposes the research and simulation of general bars of medium voltage metal enclosed switchgear, made of aluminum bars with copper contacts, in order to find a similar or even more convenient solution than that of copper bars, both from a technical and economic point of view. The goal is to improve heat distribution at the passage of the current, in the bar and particularly in contacts,...
As the successor of H.264, High Efficient Video Coding (HEVC) standard includes various novel techniques, including Coding Tree Unit (CTU) structure and additional angular modes used in intra coding. These new techniques promote the coding efficiency on one hand, while increasing the computational complexity significantly on the other hand. In this paper, we propose a fast intra block partitioning...
This paper presents a mathematical model of temperature in solar thermal which are evinced in the second-order partial differential equation. The solar thermal analysis uses copper pipe, aluminium pipe, and anodized aluminium pipe to compare temperature distribution of water from three types of pipe. In a computer simulation, 3-D finite element method established in MATLAB program were applied for...
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