Papers by Keyword: Circuit Model

Abstract: Composite La_0.88Bi_0.12Mn₀.₈₀Ni_0.20O₃ was synthesized using the conventional solid-state reaction method with sintering temperature of 1200 °C for 12 hours and the dielectric properties investigated. The X-ray diffraction result shows that the composite has a rhombohedral structure with lattice parameter of a = b = c = 5.5136 Ǻ. Scanning electron microscope shows grains with approximately from 0.8 to 5.4 μm in size with presence of voids. The dielectric permittivity, εʹ and dielectric loss, εʺ were measured in the range of 298 K to 473 K where both are temperature and frequency dependent. At 1 kHz to 100 kHz, the εʹ is around 10000 and the dielectric loss tangent, tan δ is below 1.5. The electric behavior of this composite is best represented by Quasi-dc model which consists of two universal capacitors in parallel. Parameters value from the fitting indicated that high correlations of electrons between inter and intra-clusters. The activation energy, E_a calculated from the conductivity of the sample gives a value of 0.116 eV. Vibrating sample magnetometer shows that the La_0.88Bi_0.12Mn₀.₈₀Ni_0.20O₃ has a magnetic coercivity, H_c of 36.109 G and retentivity, B_r, valued 2.7504 x 10^-3 emu/g.

Abstract: Ceramic sample of La_0.70Ba_0.30Mn_0.40Ti_0.60O₃ oxide has been prepared by the conventional solid-state reaction method. The sintered sample was characterized by using x-ray diffraction (XRD) and low frequency LCR meter. XRD result shows that the sample has a cubic structure with the existence of impurity phase. The dielectric properties of La_0.70Ba_0.30Mn_0.40Ti_0.60O₃ measured from room temperature to 200°C shows that the dielectric permittivity is temperature dependence with strong dispersion at low frequencies. A circuit model based on the universal capacitor response function is also being used to represent the dielectric properties of the sample.

Abstract: Since the manufacture of memcapacitor is complicated and memcapacitors are not commercially available yet, the memcapacitor models are of importance for the research on memcapacitor characteristics and its application. Based on the analysis of the mathematical model of the memcapacitor and its typical characteristics, the memcapacitor model is designed. Some simulation is done to validate the function of the proposed circuit model.

Abstract: Abstract. A fast and accurate equivalent circuit model for spiral inductors on lossy silicon substrate is presented and the parameters of the model are extracted without applying any fitting and optimized methods. In this model, the lateral resistance and inductance of substrate are introduced to model the eddy-current losses induced by magnetic coupling between the spiral and the substrate. FastHenry method is used to extract the inductances of spiral, substrate, and the mutual inductance between them. A numerical formulation is used to efficiently capture the proximity and skin effects in metal tracks. The proposed model is used to predict the performance of two typical spiral inductors fabricated in CMOS technology. The model shows excellent accuracy and efficiency by the comparison with measure results at the frequency from 100MHz to 10GHz.

Abstract: A circuit model of nonlinear inductor with magnetic core based on duality theory is presented in this paper. The presented circuit model of the nonlinear inductor can reflect the magnetic circuit topological structure of the magnetic core very well. The circuit model of the nonlinear inductor based on duality theory was implemented in the PSCAD software for verification. The transient temporal simulation was made at 50 Hz and 500 Hz. The validation of the circuit model based on duality theory has been verified by comparing the simulation results obtained by PSCAD software and ANSOFT software.

Abstract: Simple, physics-based, and accurate circuit models are reported for GaN power HEMTs and inductors; these models are then used to design high-performance chip-scale synchronous buck (SB) power converters to provide agile point-of-load (POL) low-voltage ( down to 1V) high-current (up to 10A) power to portable mobile devices from a battery. Excellent agreement between the measured and simulated results is demonstrated for load regulation for a 19V/1.2V, 800 kHz SB converter; for comparison, the same converter performance using the best commercially available state-of-the-art silicon power MOSFETs is also evaluated. It is shown that the conventional approach used for estimating power loss of a SB power converter is in error; a new application-specific Figure of Merit (FOM) for power switches is proposed that accounts for both input and output switching losses.

Abstract: Based on the platform of laser-triggered surface flashover in pulsed voltage, experiment of laser-triggered surface flashover switch is carried out in vacuum condition with pulsed voltage. The switch consists of flat electrodes and columned insulator. A single/double harmonic, with wavelength λ of 1064/532 nm, Q-switched Nd: YAG laser is applied to trigger the switch. The results of experiment show that switch delay time and jitter time decrease with increase of pulsed voltage and laser energy density. Based on the waveforms of switch voltage and switch current, the circuit model of laser-trigger flashover switch is set up by circuit method in the paper. The parameters of the circuit model are calculated through the waveforms of the experiment, and the waveforms of switch voltage and switch current are obtain through circuit simulation. The simulation waveforms of the switch model are consistent with the waveforms of the experiment.

Abstract: The high increase of power electronic devices use (speed control, lighting, heating, automotive, etc...) requires the electrical, thermal and electromagnetic behavior studies. In this paper we developed a model to predict the conducted EMI level in a DC/DC converter. Measurement methodology was done using a network analyzer in order to evaluate the equivalent impedance model of each converter element. The full circuit model is then implemented in the Saber® simulation tool using time domain simulation followed by fast Fourier transformation (FFT) in the frequency range 150 KHz -100 MHz. A comparison between simulation results and those obtained by measurements is used to validate the developed model.

Abstract: This paper theoretically analyzes the transfer impedance of a plane current probe. The plane current probe is an effective device that is used to measure conducted current flowing on the surface of a metal structure. One of the hot topics for plane current probe is to obtain its transfer impedance. Most research concentrates on designing calibration devices and measuring the values of the transfer impedance. However, they all do not carry out theoretical study on transfer impedance. In this paper, the equivalent circuit of the signal detection system of the probe was established based on a transformer model. Furthermore, the expression of transfer impedance was derived from the equivalent circuit. The curve shape of transfer impedance obtained from this study has a good agreement with the measured ones. This fact validates the equivalent circuit and the theoretical formula. Subsequently, influence on the value of transfer impedance was analyzed based on the expression with change of some parameters, e.g., turns of coil winding, dimension of ferrite core, permeability of ferrite core, distributed capacitance. The result gained from the above analysis will provide guidance on the design and application of the plane current probe.