Parasitic Parameters Research Articles

Wideband Electromagnetic Model and Analysis of Shielded-Pair Through-Silicon Vias

The 3-D multistrata integration puts forward high requirements for signal integrity. The shielded-pair through-silicon vias (SPTSVs) proposed in this paper feature superior transmission properties and high jamming immunity suitable for differential-mode and common-mode transmission. Based on the quasi-static field theory, a wideband impedance model of SPTSVs considering the proximity effect, the line-to-line crosstalk, and the eddy current effect is derived. The parasitic parameters calculated by the impedance model are further given. The finite-element analysis shows that the proposed model highly agrees with the 3-D full-wave simulation and the analytical calculation. In addition, the characteristics of the impedance and the transmission coefficient are deeply analyzed with different design parameters. Finally, the impacts of the substrate effect and the metal–oxide–semiconductor effect on electrical characteristics of SPTSVs are revealed.

Ecological determinants of avian malaria infections: An integrative analysis at landscape, mosquito and vertebrate community levels.

Vector and host communities, as well as habitat characteristics, may have important but different impacts on the prevalence, richness and evenness of vector-borne parasites. We investigated the relative importance of (1) the mosquito community composition, (2) the vertebrate community composition and (3) landscape characteristics on the prevalence, richness and evenness of avian Plasmodium. We hypothesized that parasite prevalence will be more affected by vector-related parameters, while host parameters should be also important to explain Plasmodium richness and evenness. We sampled 2,588 wild house sparrows (Passer domesticus) and 340,829 mosquitoes, and we performed vertebrate censuses at 45 localities in the Southwest of Spain. These localities included urban, rural and natural landscapes that were characterized by several habitat variables. Twelve Plasmodium lineages were identified in house sparrows corresponding to three major clades. Variation partitioning showed that landscape characteristics explained the highest fraction of variation in all response variables (21.0%-44.8%). Plasmodium prevalence was in addition explained by vector-related variables (5.4%) and its interaction with landscape (10.2%). Parasite richness and evenness were mostly explained by vertebrate community-related variables. The structuring role of landscape characteristics in vector and host communities was a key factor in determining parasite prevalence, richness and evenness, although the role of each factor differed according to the parasite parameters studied. These results show that the biotic and abiotic contexts are important to explain the transmission dynamics of mosquito-borne pathogens in the wild.

Improved SiC Power MOSFET Model Considering Nonlinear Junction Capacitances

Silicon carbide (SiC) power metal–oxide–semiconductor field-effect transistors (mosfet s) have been applied in high-power and high-frequency converters recently. To effectively predict characteristics of SiC power mosfet s in the design phase, a simple and valid model is needed. In this paper, a simple improved SiC power mosfet behavioral model is proposed using SPICE language. Key parameters in the model are analyzed and determined in detail, including parasitic parameters of the power module, steady-state characteristic parameters, and nonlinear parasitic capacitances. The effect of negative turn- off gate drive voltage is considered and a continuously differentiable function is proposed to describe the gate–source capacitance. Experimental validation is performed under a double pulse circuit employing an N -channel power mosfet half-bridge module CAS300M12BM2 (Cree Inc.) rated at 300 A/1200 V. The main switching dynamic characteristic parameters of the model have been compared with those of the measured results. The results show that taking gate–source capacitance as a linear value as most previous models do will cause significant turn- on deviations between experiment and simulation results, while the improved model is more accurate compared with the measured results.

Mitigation Conducted Emission Strategy Based on Transfer Function from a DC-Fed Wireless Charging System for Electric Vehicles

The large dv/dt and di/dt outputs of power devices in wireless charging system (WCS) in electric vehicles (EVs) always introduce conducted electromagnetic interference (EMI) emissions. This paper proposes a mitigation conducted emission strategy based on transfer function from a direct current fed (DC-fed) WCS for EVs. A complete test for the DC-fed WCS is set up to measure the conducted emission of DC power cables in a frequency range of 150 kHz–108 MHz. An equivalent circuit with high-frequency parasitic parameters for WCS for EV is built based on measurement results to obtain the characteristics of conducted emission from WCS. The transfer functions of differential mode (DM) interference and common mode (CM) interference were established. A judgment method of using transfer functions to determine the dominated interference mode responsible for EMI is proposed. From the comparison of simulation results between CM or DM and CM+DM interference, it can be seen that the CM interference is the dominated interference mode which causes the conducted EMI in WCS in EVs. A strategy of giving priority to the dominated interference mode is proposed for designing the CM interference filter. Finally, the conducted voltage experiment is performed to verify the mitigation conducted emission strategy. The conducted voltage of simulation and experiment is decreased respectively by 21.17 and 21.4 dBμV at resonance frequency 30 MHz. The conduced voltage at frequency range of 150 kHz–108 MHz can be mitigated to below the limit level-3 of CISPR25 standard (GB/T 18655-2010) by adding the CM interference filters.

Simulation and experimental analysis of alternating-current phenomenon in micro-EDM with a RC-type generator

In micro electrical discharge machining (micro-EDM) with a RC-type generator, due to the oscillation voltage on a sparking gap caused by the parasitic parameters in a discharge loop and the smaller discharge capacitor, the normal-discharge is usually accompanied by the alternating-current. In this research, the alternating-current phenomenon was analyzed comprehensively through theoretical analysis, electrical simulation and experimental verification. An electrical discharge model based on real experimental waveforms was provided, and the machining influences of alternating-current were investigated. It was found that the alternating-current was likely occur when the discharge capacitor restored significant energy at the end of the first normal-discharge, and it remarkably contributed to material removal on the workpiece under some conditions, which improved the machining efficiency at a limited expense. So, the process servo control and the strategy for tool wear prediction and compensation should consider the alternating-current effects or utilize it in the finishing regime and high-accuracy machining applications.

Parasitic parameters of thin film structures created on flexible substrates in PVD process

In the article the authors presented the results of the study of parasitic parameters of interdigitated electrodes (IDEs) produced in physical vacuum deposition process (PVD) on the elastic composite substrate — Cordura. Such structures can be the part of an entire electronic system created on textiles. Knowledge of the parasitic parameters of that structures allows for using them as the sensor of nonelectrical quantities. The measurements show the capacitive character of the created structures in the range of frequency up to 200kHz.

Instability Analysis and Oscillation Suppression of Enhancement-Mode GaN Devices in Half-Bridge Circuits

This paper analyzes the problem of instability in enhancement-mode gallium nitride (GaN) transistors based half-bridge circuits. The instability may cause sustained oscillation, resulting in overvoltage, excessive electromagnetic interference (EMI), and even device breakdown. GaN devices operate in the saturation region when they conduct reversely during the dead time. Under the influence of parasitic parameters, the GaN-based half-bridge circuit exhibits positive feedback under certain conditions, thus, resulting in sustained oscillation. A small-signal model is proposed to study this positive feedback phenomenon. Like the second-order under-damped system, damping ratio is defined to determine the system's stability. Based on the model, the influence of circuit parameters on instability is investigated and guidelines to suppress the oscillation are given. Reducing the common-source inductance, increasing the gate resistance of the inactive switch or connecting a diode in parallel to the inactive switch are some effective ways to suppress the oscillation. Finally, the analyses are verified by both simulation and experiment.

Reanalysis of Discharge Voltage of RC-type Generator in Micro-EDM

In micro electrical discharge machining (micro-EDM), RC-type generator is popular because of the short pulse duration with low pulse energy. According to the experimental waveforms captured in micro-EDM processing with a commercial RC-type generator, the discharge voltage had a relatively slow slope rate section during the discharge period, so a quasi maintaining-voltage assumption was proposed. Then, an electrical circuit model, considering the parasitic parameters, was established and the discharge process was analyzed theoretically. The calculated waveforms matched the experimental waveforms well, which supported the validation of the proposed electrical circuit model. The proposed electrical circuit model was also simulated and simulation results showed that the parasitic parameters would indeed have great effects on the discharge voltage.

Physical Investigation Into Effective Voltage Balancing by Temporary Clamp Technique for the Series Connection of IGBTs

The series connection of IGBTs is essential for high-voltage applications where fast switching performances need to be maintained. However, unbalanced voltage sharing is a major resistance to the converter application of this structure. There are a number of causes leading to voltage unbalance, such as different signal delays, parasitic parameters, tail currents, and so on. A temporary clamp scheme performed by active voltage control (AVC) has been proven to be effective in solving the unbalanced voltage-sharing issue. However, the basic physics has not been investigated. In this paper, the physical principle of voltage unbalance within IGBTs series operation is discussed. The carrier storage region differences are concluded to be the intrinsic cause of unbalanced voltage sharing. By using an accurate Fourier-series-based IGBT simulation model with appropriate assumptions, a physical explanation for temporary clamp is provided in detail. At the end of the tail current period when the excess carrier concentration becomes close to the intrinsic doping density, the temporary clamp is able to achieve satisfactory equal voltage sharing.

Influence of Parasitic Inductances on Switching Performance of SiC MOSFET

Compared to the silicon power devices, silicon carbide device has shorter switch time. Hence, as a result of the faster transition of voltage (dv/dt) and current (di/dt) in SiC MOSFET, the influence of parasitic parameters on SiC MOSFET’s switching transient is more serious. This paper gives an experimental study of the influence of parasitic inductance on SiC MOSFET’s switching characteristics. Most significance parameters are the parasitic inductances of gate driver loop and power switching loop. These include the SiC MOSFET package’s parasitic inductance, interconnect inductance and the parasitic inductance of dc link PCB trace. This paper therefore focuses on analysis and comparison of different parasitic parameters under various operation conditions in terms of their effect on overvoltage, overcurrent and switching power loss.

采用BCB平整技术的高速850 nm垂直面发射激光器

Vertical-cavity surface-emitting lasers(VCSELs) are widely used in short-reached optical interconnects and data communication links because of their low energy consumption and high modulation speed. Capacitance, as the parasitic parameters, affects the modulation bandwidth. In this paper, parasitic capacitance of VCSELs is reduced by using a low-k benzocyclobutene(BCB) planarization technique. The detail BCB planarization technique has been discussed with optimal process parameters, which is useful for high-speed VCSEL fabrication. The small signal modulation bandwidth of the low-k BCB planarization VCSEL with 7 μm oxide aperture has been achieved to 15.2 GHz.

A Series Diode Method of Suppressing Parasitic Oscillation for Boost PFC Converter Operated in Discontinuous Conduction Mode

When a boost power factor correction converter operates in a discontinuous conduction mode, the nonzero characteristic of the average current in oscillation period and the initial value of the inductor current in a switching cycle are the main cause of the influence of the parasitic parameters on input current distortion. The effect of parasitic parameters oscillation is analyzed in detail, and a new method of series diode is proposed, which can effectively decrease the input current distortion and improve the power factor. Selection principles of series diode are given. Experimental results verify the correctness and the feasibility of the theoretical analysis.

Phase‐shift full bridge power supply based on SiC devices

In order to accurately obtain the switching characteristics of SiC MOSFET in practical application, a dual pulse test circuit is used to test the SiC MOSFET in this subject. By analysing the double pulse test circuit and taking into account the parasitic parameters, the effects of different gate resistances ( R g ) and the capacitance between gate and source ( C gs ) on the switching characteristics of the SiC MOSFET are summarised. Also, a phase-shifted full-bridge power supply based on SiC device is designed, which can be changed from 270 V direct current (DC) to 220 V alternating current (AC)/50 Hz, which consists of two stages. The first stage is the phase shifted full bridge ZVS DC/DC converter, which will boost the 270 V DC to the 350 V DC; the latter is a single-phase full bridge inverter, and the 350 V DC will be converted to the 220 V AC/50 Hz. The power supply uses the SiC MOSFET as the switch tube, which can reduce the switching loss, improve the switching frequency and reduce the volume of the transformer. A rectifier circuit using a SiC Schottky diode, with almost no reverse recovery process, greatly reduced the transformer side parasitic oscillation and improved the efficiency of the power supply. In this study, the design method of the parameters of the power supply is described in detail. Finally, the rationality of the design of the power supply parameters is verified by MATLAB/Simulink simulation and experimental prototypes.

Universal Pseudo-Differential Filter Using DDCC and DVCCs

In the paper, a universal preudo-differential second-order filter operating in voltage mode, where both intup and output are differential, is presented. The circuit is formed by one differential difference current conveyor (DDCC), two differential voltage current conveyors (DVCCs), and five passive elements. The filter is characterized by high input impedance, minimum number of passive elements that are all grounded, and high common-mode rejection ratio (CMRR). The proposed filter structure is able to realize all five standard frequency filter responses. Non-ideal analysis has been performed by considering the real parasitic parameters of the active elements. The optimization of passive element values has been done in terms of minimal shift of the pole-frequency and to obtain the maximum stop-band attenuation of the high-pass filter response. Functionality is verified by simulations and experimental measurements using readily available integrated circuit UCC-N1B 0520. DOI: http://dx.doi.org/10.5755/j01.eie.23.6.19694

Electromagnetic interference modeling and suppression techniques in variable-frequency drive systems

Electromagnetic interference (EMI) causes electromechanical damage to the motors and degrades the reliability of variable-frequency drive (VFD) systems. Unlike fundamental frequency components in motor drive systems, high-frequency EMI noise, coupled with the parasitic parameters of the trough system, are difficult to analyze and reduce. In this article, EMI modeling techniques for different function units in a VFD system, including induction motors, motor bearings, and rectifier-inverters, are reviewed and evaluated in terms of applied frequency range, model parameterization, and model accuracy. The EMI models for the motors are categorized based on modeling techniques and model topologies. Motor bearing and shaft models are also reviewed, and techniques that are used to eliminate bearing current are evaluated. Modeling techniques for conventional rectifier-inverter systems are also summarized. EMI noise suppression techniques, including passive filter, Wheatstone bridge balance, active filter, and optimized modulation, are reviewed and compared based on the VFD system models.

A 50-kW High-Frequency and High-Efficiency SiC Voltage Source Inverter for More Electric Aircraft

High power density is required for power converter in more electric aircraft due to the strict demands of volume and weight, which makes silicon carbide (SiC) extremely attractive for this application. In this paper, a prototype of 50-kW SiC two-level three-phase voltage source inverter is demonstrated with a gravimetric power density of 26 kW/kg (without inclusion of filter). A gate assisted circuit is introduced to reduce the switching loss. In addition, the ringings of voltage and current due to parasitic parameters during the switching transition can also be mitigated. A mathematical model with consideration of various parasitic parameters is developed, which illustrates the parasitic effects in high-speed switching SiC power module. The converter is operated at a switching frequency up to 100 kHz and a narrow dead band of 250 ns. The measured efficiency is 97.91%.

MHz zero‐voltage‐switched isolated resonant converter for wide‐output‐voltage application

This study proposes a MHz isolated resonant converter, which achieves buck–boost DC/DC conversion, zero-voltage switching and the resonant components absorb the parasitic parameters. The DC analysis method and MATLAB computational algorithm are proposed for acquiring the specific circuit characteristics, including the voltage conversion ratio, the rms value of switch current and peak voltage of the semiconductors. The active power and apparent power are also analysed to provide design basis of optimising efficiency. The proposed converter shows greater advantages on voltage stress, current stress and efficiency over traditional isolated Sepic multi-resonant converter. A wide-output-voltage prototype based on the proposed converter was built in the lab and the experimental results verify the theoretical analysis well.

A low-cost W-band SPDT switch with Q-MMIC concept using quartz substrate

In this paper, a high-performance PIN diode single-pole-double-throw (SPDT) switch for W-band application is developed. By employing quasi-monolithic millimeter-wave integrated circuit (Q-MMIC) technology, the cost of the switch is significantly reduced while maintaining performance and size with conventional MMIC counterpart. A 3-D PIN diode model is used to describe the diode characteristic under both forward and reverse biasing states. In order to alleviate parasitic parameters effect on performance of the switch, compensation structures are analyzed and adopted. The measurement results show the insertion loss is less than 2 dB from 82 to 100 GHz and the isolation is greater than 32 dB from 82 to 105 GHz. The total size of the SPDT switch is 2.1 mm × 4.3 mm.

Research on Fast Transient Pulse Group Suppression Filter

With the popularization of electronic products, the electromagnetic compatibility problem of electronic equipment is more and more prominent. The suppression of electric fast transient burst (EFT / B) generated by switching power supply is an important research content. Based on the principle of EFT / B, this paper analyzes the basic principles and methods of EFT filter design, and uses the "negative parameter cancellation method" to deal with the design of the filter according to the parasitic parameters of the components that make up the filter Sexual adjustment, to achieve effective suppression of EFT / B noise purposes.

Modulation system and modulation characteristics of high power semiconductor laser

In this paper, we studied the factors that affect the high frequency modulation performance of semiconductor laser in the process of direct modulation. The equivalent circuit model of LD is derived from the rate equation of semiconductor laser, which was established by using PSpice. We analyzed the effects of the parasitic parameters, the DC bias and the current modulation intensity on modulation characteristics of the laser, and put forward the corresponding methods to improve the performance of modulation. We designed a direct modulation system of semiconductor laser and simulated the system by OrCAD/PSpice. This system can output modulation semiconductor laser with frequency of 1 MHz and average power of 1.1 W.