Research and Modeling on the Characteristic Changes of EMI Filter Passive Components under the Influence of Aging

At present,the power density of power electronic devices in data centers and electric vehicles is constantly increasing,and numerous electronic components are concentrated in a tight,high-temperature environment,which aggravates the performance degradation of electronic components.Consequently,X and Y capacitors,common-mode inductors,and differential-mode inductors used for electromagnetic interference(EMI)suppression suffer from aging effects,and their performance continues to decline.However,the electromagnetic compatibility test is often conducted immediately after the power electronic equipment leaves the factory.The electromagnetic compatibility of power electronic equipment is affected by aging,which is not assessed in current industrial testing.This study conducts aging experiments on passive electronic components in EMI filters and measures the impedance in the frequency range from 150 kHz to 30 MHz.Subsequently,a multi-element aging model based on electromagnetic field analysis is established.The proposed model is suitable for electromagnetic compatibility analysis considering aging.Finally,the aging performance of a commercial two-stage EMI filter is predicted to verify the model proposed in the study.The proposed model explains the degeneration of the EMI filter with aging in the frequency range of 150 kHz to 1 MHz,with a maximum amplitude error of 0.58 dB and phase error of 1.0°.

Suppression of ferroresonance using passive memristor emulator

Power system inherently consists of capacitance and inductance in its components. Equipment with saturable inductance and circuit capacitance provides circumstances of generating ferroresonance, resulting in overvoltage and overcurrent in the connected system. The effects of ferroresonance result in insulation failure and hence damage to the equipment is unavoidable. Though many devices are proposed for mitigating such circumstances, a promising technology of using memristors may provide better performance than others in the future. A memristor emulator using the N-channel JFET J310 is used in this work. Unlike other electronic components that replicate memristor properties, the chosen memristor emulator is a passive device since it does not need any external power supply. Simulation and experimental results verify the design of a memristor emulator and the characteristics of an ideal memristor. Experimental results prove that the memristor emulator can suppress the fundamental ferroresonance induced in a prototype single phase transformer. The results of the harmonic analysis also validate the memristor performance against the conventional technique.

The Art of Power Dividing:A Review for State-of-the-Art Planar Power Dividers

In this paper,massive state-of-theart planar power dividers are presented and discussed. The innovations of these superiorly-performanced power dividers lie in the performance breakthrough,physical configurations and function integrations. Eventually,based on the trend presented,the future of the power dividers is predicted. This paper might have inspiration significance to illuminate the way for the development of power dividers.

Investigation on Suspended Stripline and End-Coupled Bandpass Filter

In this paper, the variational method combined with Green's function is used to analyze the characteristics of suspended, stripline. The result is in good agreement with references. The design of mm-wave end-coupled bandpass filter with suspended substrate is discussed. The computer programs for design of suspended stripline and bandpass filter are established.

Multi-Gbit/s 60 GHz Transceiver Analysis Using FDM Architecture and Six-Port Circuit

This paper presents an analysis and validation by advanced system simulation of compact and low-cost six-port transceivers for future wireless local area networks （WLANs） operating at millimeter-wave frequencies. To obtain realistic simulation results, a six-port model based on the measurement results of a fabricated V-band hybrid coupler, the core component, is used. A frequency-division multiplexing scheme is used by introducing four quadrature phase-shift keying （QPSK） channels in the wireless communication link. The data rate achieved is about 4 Gbit/s. The operating frequency is in the 60-64 GHz unlicensed band. Bit error rate （BER） results are presented, and a comparison is made between single-carrier and multicarrier architectures. The proposed wireless system can be considered an efficient candidate for millimeter-wave communication systems operating at quasi-optical data rates.

A Novel Computing Method for Mutual Inductance

The design process for integrated inductors generally requires a geometry optimization step. During this step, many geometries must be simulated and fast and accurate formulae are therefore required for the computation of self and mutual inductances of turns. This paper especially deals with numerical evaluation of the mutual inductance of two coaxial circular wire loops. Several computation methods are presented and compared. Finally, an expression is built-up and proven to be very few computing time consuming and 1% accurate for any kind of geometry. The application of this expression to integrated inductive components modelization is recalled to mind, however, this work gives a general and fast computable solution to the electromagnetic problem.

Functional Fibers and Functional Fiber‑Based Components for High‑Power Lasers

The success of high-power fiber lasers is fueled by maturation of active and passive fibers,combined with the availability of high-power fiber-based components.In this contribution,we first overview the enormous potential of rare-earth doped fibers in spectral coverage and recent developments of key fiber-based components employed in high-power laser systems.Subsequently,the emerging functional active and passive fibers in recent years,which exhibit tremendous advantages in balancing or mitigating parasitic nonlinearities hindering high-power transmission,are outlined from the perspectives of geo-metric and material engineering.Finally,novel functional applications of conventional fiber-based components for nonlinear suppression or spatial mode selection,and correspondingly,the high-power progress of function fiber-based components in power handling are introduced,which suggest more flexible controllability on high-power laser operations.

CPW Circulators with Barium Ferrite Thin Films

A miniaturized circulator using barium ferrite films with a coplanar waveguide （CPW） structure is designed and optimized by high frequency electromagnetic field simulations based on finite element methods. The best circulation performance of the film circulator based on 10 pm thick barium ferrite thin films is obtained with an insertion loss of 0.13 dB and an isolation of 22.89 dB around 36.9 GHz. The microwave characteristics of film circulators with CPW and CPW with ground （CPWG） structures have been compared. The influences of the gap between the ground and the signal line, and the ferromagnetic resonance line width on the microwave properties are also studied.

Topology of Current-limiting and Energy-transferring DC Circuit Breaker for DC Distribution Networks

With the development of power electronic technologies and distributed power generation,DC distribution networks attract increasing attention due to their various advantages compared with traditional AC distribution networks.However,DC fault protection is one of the major issues in DC distribution networks.To improve their reliability and protect the semiconductor devices under DC faults,a current-limiting and energy-transferring DC circuit breaker topology is proposed in this paper.By applying passive components and thyristors,the proposed topology is capable of quickly limiting the fault current and transferring the faulty energy.The working principle,mathematical model and parameter designing method of the proposed topology are presented in this paper.The simulation results verify that the proposed DC circuit breaker could effectively limit the fault current and quickly interrupt the fault current.Cost and conduction power loss evaluation proves the practicality of the proposed topology in medium-voltage DC distribution networks.