Nonlinear Inductance Research Articles

Properties of TiN for Detector and Amplifier Applications

We have experimentally explored and carefully characterized the important properties of TiN, including the resistivity, nonlinear kinetic inductance, the anomalous electro-dynamical response, and the two-level-system induced frequency shift and noise. We suggest that some of these properties, which are not well understood and are different from conventional superconductors, need further study and special consideration in kinetic inductance detector and parametric amplifier applications.

Bouc–Wen Hysteresis Model Identification by the Metric-Topological Evolutionary Optimization

From a computational point of view, the identification of Bouc-Wen (BW) hysteresis model is a hard task due to the large number of parameters to be found. This is one of the reasons for which it is rarely used for modeling magnetic hysteresis, where other hysteresis models are widely used (e.g., Preisach and Jiles-Atherton). However, the opportunities that the differential expression of BW model could offer for its use in more complex computation task (e.g., nonlinear inductors inserted into a circuit and so on) justify a deeper investigation on its adoption in ferromagnetism. In this paper, using a new hybrid heuristic called metric-topological-evolutionary optimization (MeTEO), the BW identification is presented. MeTEO is a powerful algorithm based on a synergic and strategic use of three evolutionary heuristics: 1) the flock-of-starlings optimization, which shows not only high exploration capability, but also a lack of convergence; 2) the particle swarm optimization, which has a good convergence capability; and 3) the bacterial chemotaxis algorithm, which has no collective behavior or exploration skill, but has high convergence capability. MeTEO is designed to use parallel architectures and exploits the fitness modification technique. Numerical validations are presented in comparison with the performances obtained using other approaches available in the literature.

Simulation and Analysis of Superconducting Traveling-Wave Parametric Amplifiers

Superconducting parametric amplifiers have great promise for quantum-limited readout of superconducting qubits and detectors. Until recently, most superconducting parametric amplifiers had been based on resonant structures, limiting their bandwidth and dynamic range. Broadband traveling-wave parametric amplifiers based both on the nonlinear kinetic inductance of superconducting thin films and on Josephson junctions are in development. By modifying the dispersion property of the amplifier circuit, referred to as dispersion engineering, the gain can be greatly enhanced and the size can be reduced. We present two theoretical frameworks for analyzing and understanding such parametric amplifiers: 1) generalized coupled-mode equations and 2) a finite difference time domain (FDTD) model combined with a small signal analysis. We show how these analytical and numerical tools may be used to understand device performance.

Estimation of phase inductance profile in a three-phase 6/4 pole switched reluctance machine

This paper presents a non-linear inductance profile estimation of a Switched Reluctance Machine (SRM) using real-time applicable modelling techniques. The estimation techniques are based on regression analysis and Adaptive Neuro-Fuzzy Inference System (ANFIS). Mathematical models of phase inductance L(I,θ) using both the techniques have been successfully tested for various values of phase currents (Iph) and rotor positions (θ) of a non-linear SRM. It is observed that the proposed techniques are highly suitable for inductance L(I,θ) modelling of SRM, which is found to be in good agreement with the training data used for modelling.

High-Performance Electromechanical Actuator Dynamic Heat Generation Modeling

All-electric aircraft is a high-priority goal in the avionics community. Both increased reliability and efficiency are the promised implications of this move. But, thermal management has become a significant problem that must be resolved before reaching this goal. Electromechanical actuators (EMAs) are of special concern. Advanced analysis technologies such as the finite element method (FEM) and intelligent control systems such as field-oriented control (FOC) are being used to better understand the source of the heat and to eliminate as much of it as possible. This paper describes the nonlinear, lumped-element, integrated modeling of a permanent magnet (PM) motor used in an EMA. The parameters, including nonlinear inductance, rotor flux linkage, and thermal resistances and capacitances, are tuned using FEM models of a real, commercial actuator. The FOC scheme and the lumped-element thermal model are also described.

SPICE-like Models for Nonlinear Capacitors and Inductors

Some new models for nonlinear capacitors and nonlinear inductors built with SPICE-like element primitives are presentedhere. They have the advantage that they can be used for simulation in SPICE of those circuits which contain nonlinearcapacitors controlled either in voltage or in charge, and nonlinear inductors controlled either in current or in flux. TheseSPICE-like models contain current sources whose controlling variables are charge time-derivative and sources whosecontrolling variables are flux time-derivative. For validation, the models are included in nonlinear circuits; their behavior isstudied by simulation using two different simulators and the results are compared.

Research on Nonlinear Modeling for Power Transformer over Wide Frequency Range

This paper proposes a new nonlinear broadband model of the power transformer which is both fit for steady state and transient simulation in power system. The model consists of high-frequency module and low-frequency module in parallel. Based on the black-box method, the high-frequency block is built in the form of π-type equivalent circuit, and the low-frequency block is in the form of conventional gamma-type circuit, in which core saturation characteristic is expressed by a nonlinear inductor. A power transformer is studied in the laboratory, simulations and experiments are carried out in case of power-frequency steady state, excitation currents distortions, lightning overvoltage, and very fast transient overvoltages (VFTO) respectively. The comparisons between the simulated and measured results verify the feasibility and validity of the model.

Measuring the superconducting coherence length in thin films using a two-coil experiment

We present measurements of the superconducting coherence length $\ensuremath{\xi}$ in thin ($d\ensuremath{\le}100\ensuremath{-}\AA{}$) films of MoGe and Nb using a combination of linear and nonlinear mutual inductance techniques. As the alternating current in the drive coil is increased at a fixed temperature, we see a crossover from linear to nonlinear coupling to the pickup coil, consistent with the unbinding of vortex-antivortex pairs as the peak pair momentum nears $\ensuremath{\hbar}/\ensuremath{\xi}$ and the unbinding barrier vanishes. We compare measurements of $\ensuremath{\xi}$ performed by this mutual inductance technique to values determined from the films' upper critical fields, thereby confirming the applicability of a recent calculation of the upper limit on a vortex-free state in our experiment.

Oscillating Pulse Generator Based on a Nonlinear Inductive Line

A chain of cascading LC sections consisting of series nonlinear inductors and parallel linear capacitors can be used to generate oscillating pulses. When a rectangular pulse is injected into the input of such a nonlinear inductive line (NLIL), the pulse undergoes modulation and exits at the output with oscillations in the waveform. This paper describes the implementation of high-voltage NLILs using commercial-off-the-shelf components. A pulser comprising of a storage capacitor and a fast semiconductor switch is used to provide the input pulse with approximate rectangular pulse shape. The design of the NLIL, which is a type of nonlinear lumped element transmission line (NLETL), is based on a NLETL circuit model developed earlier in-house. The nonlinear inductors made of ferrites are modeled using a simplified form of the Landau-Lifshitz-Gilbert (LLG) equation. A simple novel approach is proposed to determine the characteristic parameters in the LLG equation. Simulation results from the NLETL model are compared to the experimental results, and analyses on the voltage modulation and frequency content of the output pulses are performed. The use of crosslink capacitors in the line to modify the dispersive characteristics to enhance the performance is also investigated. With the results, the conditions and trends for producing oscillating pulses in NLILs are discussed.

SPMSM 인덕턴스 돌극성에 의한 전류리플 저감을 위한 PSO 알고리즘 기반의 H∞전류 제어기 설계

The useful method for determining parameters of weighting functions used to design the H<SUB>∞</SUB> current controller for attenuating the current ripple due to saliencies which SPMSM(Surface Permanent Magnet Synchronous Motor) also incorporates is described. To analyze the effect, the current ripple due to the structural and the saturation saliencies, the SPMSM model with nonlinear inductance function depending on the two independent variables, rotor position and stator current is simulated. After analysis, parameters of the weighting functions for H<SUB>∞</SUB> current controller is selected to satisfy the robust stability, robust performance and specific performance in time and frequency domain by using the PSO(Particle Swarm Optimization) algorithm in the linear SPMSM model. Especially, the robust performance is proved that the selected weighting functions play a role in reducing the current ripple caused by the saliencies of SPMSM at the desired frequency range by the simple experiment.

A one-dimensional tunable magnetic metamaterial

We present experimental data on a one-dimensional super-conducting metamaterial that is tunable over a broad frequency band. The basic building block of this magnetic thin-film medium is a single-junction (rf-) superconducting quantum interference device (SQUID). Due to the nonlinear inductance of such an element, its resonance frequency is tunable in situ by applying a dc magnetic field. We demonstrate that this results in tunable effective parameters of our metamaterial consisting of 54 rf-SQUIDs. In order to obtain the effective magnetic permeability μr,eff from the measured data, we employ a technique that uses only the complex transmission coefficient S₂₁.

On determination of inductances for circuit models of AC machines

Abstract The paper discuss a problem of determination of inductances for AC machine windings when saturation of magnetic circuit is not neglected. For such cases, computation of magnetic field distribution in the machine magnetic circuit is a starting point for post processing procedures leading to various values, among others the co-energy in a given area and linkage fluxes of windings. This paper shows how to determine winding inductances in a nonlinear magnetic circuit from these two values and also how to compute directly nonlinear inductances. Problem is not trivial because such inductances are not uniquely determined as for linear case. In the paper a definition of nonlinear inductances is proposed which makes the choice unique.

Design and Evaluation of a High-Frequency LTCC Inductor Substrate for a Three-Dimensional Integrated DC/DC Converter

High operating frequency and integration technique are two main approaches to achieve high power density for the switching mode power supply. The emerging gallium nitride (GaN)-based power device enables a multimegahertz high-efficiency point-of-load (POL) converter with high current capability. The low-temperature cofire ceramic (LTCC)-based integration technique successfully extends the three-dimensional (3-D) integrated POL module from the low current level to the high current level (>10 A). This paper presents the low-profile LTCC inductor substrate design and evaluation for a multimegahertz 3-D integrated POL converter with large output current. The detailed study about the impact of frequency on the LTCC inductor shows that the high frequency not only shrinks the volume of the inductor, but also simplifies the inductor structure. The comparison between the LTCC inductor and the discrete inductor demonstrates that the LTCC inductor dramatically boosts the converter light-load efficiency due to its nonlinear inductance. Because of the low-profile design, the power density of the single-phase POL module with LTCC inductor achieves 1.1 kW/in3 at 5 MHz. The performance of the LTCC inductor can be further improved by the inverse coupling, which results in more than 40% core thickness and core loss reduction. Therefore, the power density of a two-phase integrated POL module is pushed to 1.5 kW/in3, which is around ten times of the power density of state-of-the-art industry products with the same current level.

Nonlinear Transmission Lines Using Substrate Integrated Waveguides in LTCC

The generation and transmission of relatively short duration, broadband, peak pulse power bursts has numerous applications in the communications and defense sectors. In the past, nonlinear transmission lines (NLTLs) have been used to create such broadband pulses. While most NLTL designs are based on nonlinear capacitors or inductors arranged in a ladder network, the method presented here replaces the transmission line with a novel ferroelectric filled waveguide. When a large transient voltage is input to the guide the resulting electric field will cause the polarization field to move into the saturation region. This reduces the effective dielectric permittivity and thus the group velocity of the peak power portion of the wave is faster than all other portions of the pulse. This results in the middle portion of the pulse overtaking the leading edge and “piling-up” energy at the front edge of the pulse, creating what appears to be a temporal compression of the leading edge. The temporal compression results in increased harmonic spectral content. The simulated NLTLs can be fabricated using Substrate Integrated Waveguides (SIW) in low temperature cofired ceramics (LTCC). Closely spaced vias form trenches in the waveguide that are used to create space for the nonlinear dielectric and the trenches are filled with ferroelectric materials using a sol-gel method. The trench dimensions and type of ferroelectric fill material for each layer are determined using a genetic algorithm optimization routine that produces a maximum rise time compression of the input pulse.

Artificial Inductance Concept to Compensate Nonlinear Inductance Effects in the Back EMF-Based Sensorless Control Method for PMSM

The back EMF-based sensorless control method is very popular for permanent magnet synchronous machines (PMSMs) in the medium- to high-speed operation range due to its simple structure. In this speed range, the accuracy of the estimated position is mainly affected by the inductance, which varies at different loading conditions due to saturation effects. In this paper, a new concept of using a constant artificial inductance to replace the actual varying machine inductance for position estimation is introduced. This facilitates greatly the analysis of the influence of inductance variation on the estimated position error, and gives a deep insight into this problem. It also provides a simple approach to achieve a globally minimized position error. A proper choice of the artificial machine inductance may reduce the maximum position error by 50% without considering the actual inductance variation in the control algorithm. Analytical and experimental results are given for validating the proposed theory.

Bifurcation, mode coupling and noise in a nonlinear multimode superconducting microwave resonator

The addition of nonlinearity to an harmonic resonator provides a route to complex dynamical behaviour of resonant modes, including coupling between them. We present a superconducting device that makes use of the nonlinearity of Josephson junctions to introduce a controlled, tunable, nonlinear inductance to a thin film coplanar waveguide resonator. Considering the device as a potential quantum optical component in the microwave regime, we create a sensitive bifurcation amplifier and then demonstrate spectroscopy of other resonant modes via the intermode coupling. We find that the sensitivity of the device approaches within a factor two quantitative agreement with a quantum model by Dykman but is limited by a noise that has its source(s) on-chip.

Nonlinear Modeling of Magnetic Inductor with Hysteresis in Pspice

A nonlinear modeling of magnetic inductor with hysteresis using PSpice is presented. The describing functions are used to model the high frequency hysteresis to make up the defect of Jile-Atherton static hysteresis mathematical model. The subcircuits which include the nonlinear magnetic inductor are used to the circuit of filter by PSpice. The hysteresis-related characteristic of intermodulation distortion and corner frequency can be predicted by the improved inductor subcircuit models have been verified experimentally.

Comparison of Four Different Types of Ferromagnetic Materials for Fault Current Limiter Applications

A comparison of neodymium, samarium-cobalt, aluminum-nickel-cobalt, and laminated steel is presented for use in fault current limiter applications. The ferromagnetic material properties are modeled using the Preisach method of hysteresis. The nonlinear inductance of each magnetic core is calculated and displayed. Only the material properties are changed during each consecutive simulation and are subjected to distribution system parameters to assess their fault current limitation applicability. Finite-element analysis is performed on the casing and coils of the mechanical design structure of the new hybrid fault current limiter. A new fault current limiter topology is presented and simulated in Piecewise Linear Electrical Circuit Simulation. The simulated results show the effect of different materials on the current limiter's performance. Conclusions are made that neodymium is the most suitable ferromagnetic material (of the materials tested) for fault current limiter applications.

Analysis and prediction of loudspeaker large-signal symptoms

Nonlinear lumped-parameter force factor Bl(x), stiffness Kms(x) and inductance Le(x) of electrodynamic loudspeakers change frequency responses and generate some nonlinear effects for large stimulus: harmonic and intermodulation distortion, DC component in diaphragm displacement, instability of vibration and jumping effects. By modeling the nonlinear system under large-signal conditions, relationship between the nonlinear parameters and large-signal behavior can be revealed and help to provide guidance to diagnose loudspeakers. Agreement between the measured and predicted responses of a real loudspeaker validates the modeling and enables new methods for loudspeaker diagnosis.

SPICE circuit model of voltage excitation fluxgate sensor

A simulation program with integrated circuit emphasis (SPICE) circuit model of voltage excitation fluxgate was proposed. It used the arctangent function to describe the hysteresis loop of fluxgate core, the excitation and measurement coils of the fluxgate were equivalent to a circuit model that contains a kind of non-linear time-varying inductance. Moreover, the expression of non-linear time-varying inductance has been given, which resolved fluxgate modelling itself into solving non-homogeneous ordinary differential equations with variable coefficient, and then the authors used HSPICE to solve the differential equations. The input and output characteristics of the dual-core fluxgate were simulated by this SPICE model. The results show that the model can better simulate the input and output characteristics of actual fluxgate, which verifies the validity of the model.