Iron Core Inductor Research Articles

A model order reduction of hysteretic eddy-current fields in electric machines using Cauer ladder network method

This study aims to establish a hysteretic model order reduction method for electric machines using the Cauer ladder network (CLN) method. The first inductor of the CLN represents the hysteresis effect, which is computed using the scalar play model identified from the static I–ϕ (current–magnetic flux) loops. An iron-core inductor was analyzed, and pulse-width modulation (PWM) voltage input was applied to the coil. The proposed method yielded results that agreed with the transient finite element (FE) analysis and effectively reduced the computation time.

Variable Switching Frequency Scheme Minimizing Inductor Saturation Margin for Totem-Pole Rectifier Based on Frequency-Domain Ripple Analysis

Powdered iron core (PIC) inductors demand a considerable design margin to avoid magnetic saturation, limiting the converters’ power density. This article formulates a frequency-domain method to assess the saturation’s influence on the current ripple, and proposes an optimal variable switching frequency scheme to offset the harmonics growth. A Totem-Pole rectifier prototype is built to estimate this scheme. Its harmonics distortion is reduced by 0.69% without causing instability or extra power loss. Thus, deeper saturation is allowed for PIC inductors and the saturation margin is narrowed, shrinking inductor’s volume by 2/3 to reach a higher power density.

Dynamics of the electromechanical sieve with hysteretic iron-core inductor

Dynamics of the electromechanical sieve with hysteretic iron-core inductor

Model order reduction of nonlinear eddy-current field using parameterized CLN

PurposeThe authors derive a nonlinear MOR based on the Cauer ladder network (CLN) representation, which serves as an application of the parameterized MOR. Two parametrized CLN representations were developed to handle the nonlinear magnetic field. Simulations using the parameterized CLN were also conducted using an iron-cored inductor model under the first-order approximation.Design/methodology/approachThis work studies the effect of parameter variations on reduced systems and aims at developing a general formulation for parametrized model order reduction (MOR) methods with the dynamical transition of parameterized state.FindingsTerms including time derivatives of basis vectors appear in nonlinear state equations, in addition to the linear network equations of the CLN method. The terms are newly derived by an exact formulation of the parameterized CLN and are named parameter variation terms in this study. According to the simulation results, the parameter variation terms play a significant role in the nonlinear state equations when reluctivity is used, while they can be neglected when differential reluctivity is used.Practical implicationsThe computational time of nonlinear transient analyses can be greatly reduced by applying the parameterized CLN when the number of time steps is large.Originality/valueThe authors introduced a general representation for the dynamical behavior of the reduced system with time-varying parameters, which has not been theoretically discussed in previous studies. The effect of the parameter variations is numerically given as a form of parameter variation terms by the exact derivation of the nonlinear state equations. The influence of parameter variation terms was confirmed by simulation.

Fully printed resonance-free broadband conical inductors using engineered magnetic inks

The current technologies of 3D printing have a huge potential in the domain of printed radio frequency (RF) electronic components, such as resistors, capacitors, inductors, and transmission lines. In this paper, we present the design, fabrication, and characterization of fully 3-D printed conical inductors for broadband applications. The cores of these conical-shaped inductors were all printed by engineered magnetic/dielectric materials: the first one with a polymer core was printed by the aerosol-jet (AJ) printing technology as a reference, the second one with an iron-cobalt core fabricated by a paste-extrusion (PE) method using our developed iron-cobalt-based magnetic ink, and the third one with a core fabricated (by the PE method) using iron-based powder. The conical inductor was placed at a 45° angle by mounting it on a lattice support structure, and this configuration ensured a reduction of the parasitic capacitance between the inductor and the substrate. As a result, it was possible, to achieve a resonant-free broadband performance beyond the Ka-band (26.5–40 GHz), thereby outperforming the commercial off-the-shelf (COTS) products. Numerical simulations were also performed to explain the inductor performance and pinpoint the optimal model parameters. As suggested by the lumped circuit model, the operational frequency of the fully 3D printed iron-powder-based-core inductor could be as high as 67 GHz, which is nearly two times larger than the commercial iron core inductor.

3D MEMS In-Chip Solenoid Inductor With High Inductance Density for Power MEMS Device

In this letter, we report the design and measurement of a 3D solenoid inductor that is embedded in a Si substrate and can integrate an iron core. Various inductor designs were fabricated with good structural integrity and repeatability via a CMOS-compatible MEMS fabrication process. The average inductance and quality factor peak-to-peak variation of the inductors was below 10%, which indicates that the fabrication process is repeatable. Among the inductors without iron cores, the highest quality factor (37.6 at 21 MHz) was found in a 5-turn inductor, and the highest inductance and inductance density (respectively, 86.6 nH and 21.7 nH/mm2) were found in a 20-turn inductor. Among the iron-core inductors, the 15-turn inductor had an inductance of 1063 nH and an inductance density of 354.3 nH/mm2, nearly 18 times higher than the same design without an iron core, which is the highest inductance density for a MEMS microinductor to the best of our knowledge. This type of inductor is an important component in RF MEMS and electromagnetic power MEMS devices and can improve their performance and efficiency.

Direct-write printed broadband inductors

The capability to additively manufacture fully-functioning electronic circuits is a frontier in 3D-printed electronics that will afford unprecedented scalability, miniaturization, and conformability of electronic circuits. The printed passives, such as resistors, capacitors, and inductors, however, are rarely capable of performances comparable to that of the commercially available versions. In this paper, we report a novel procedure that employs three-dimensional (3D) additive manufacturing techniques to fabricate high-frequency, tapered-solenoid type inductors for RF applications capable of wide bandwidth performance. The design includes a polymer support structure to reduce the parasitic capacitance between the inductor and the substrate, a tapered solid core, and conducting windings. Each design component is printed using aerosol-jet (AJ) printing methods on a grounded coplanar waveguide such that the small end of the conical-shaped inductor is connected to the transmission line and the base of the inductor is connected to ground. Two types of solid-core inductors were fabricated: one with a printed polymer core and another with a non-printed iron core. Scattering parameter measurements establish that the polymer and iron-core inductors, combined with a 45°-polymer support structure, can achieve usable bandwidths up to 18 GHz and 40 GHz, respectively, with low insertion loss. 3D model and circuit model simulations were also carried out to study inductor performance in terms of self-resonance and insertion loss.

Robust Lightning Indirect Effect Protection in Avionic Diagnostics: Combining Inductive Blocking Devices With Metal Oxide Varistors

The combination of iron core inductors and metal oxide varistors has been modeled and experimentally characterized to propose a robust protection system for indirect lightning effects in avionic environment. In particular, a numerical procedure to design transient limiters with high current rating, low clamping voltage, and low degradation rate is presented and described in detail. The protection systems are modeled using a circuital approach based on the diffusion equation, which is implemented in a finite difference time domain scheme. Two different modeling approaches to represent the nonlinearity and the hysteretic behavior of an iron core inductor are presented and discussed. Simulation results are verified by pin injection tests following the specific standards for avionic diagnostics.

Dynamics of a RLC series circuit with hysteretic iron-core inductor

Inductive devices with ferromagnetic core are widely used in many electronic circuits to store magnetic energy. They should be treated as nonlinear devices, and the nonlinearity of their characteristics arises from the dependence of inductance on current. Such inductors display saturation and hysteresis behaviors. In the present paper, we report a new mathematical model based on the experimental data of hysteresis for ferromagnetic core inductors. We used the model to determine analytically the expression of current in a RLC series circuit forced by an alternating source. Multi periodic and high amplitude chaotic signals are observed and good agreement is found between theoretical and experimental results.

Simulation of the Magnetic Freezing Process Applied to Foods

Magnetic field (MF) freezing of foods is an innovative process already developed at the industrial level. However, the real interaction among the variables taking place in the process is not yet given in the literature because the MF distribution inside the volume of the processing cell is still not well studied. This fact jeopardizes both drawing correct conclusions about the synergy produced by the programmed combination of physical agents and achieving an optimal design of the processing device. Three different representative magnetic freezing processes applied to foods are here dealt representing the modeling of the distribution of the MF around the foods. One of them is based on the application of a static MF produced from magnets in a laboratory freezer. Another one is promoted by the action of an oscillatory magnetic field (OMF) produced by an iron core inductor device disposed also in a laboratory freezer. The third one also is based on the action of an OMF produced by using air core inductor coils simulating the performance of a commercial food freezer. With the aim of understanding the interactions between foods and MF necessary to support beneficial actions of its presence during freezing, analytical, numerical modeling, and experimental procedures have been studied and are here reviewed. Taking into account the accuracy afforded by using modeling and considering also the difficulty of performing experimental determinations of MF inside the volume of the device during a real freezing process, the modeling procedure seems to be a very suitable and practical tool to know about the MF distribution in it. Due to the very different behaviors of the MF vectors that can be found depending on the design of the freezer and the location of the sample inside, it is recommended to perform a previous specific mathematical modeling for each planned MF freezing process applied to foods.

Design and Comparison of a 10-kW Interleaved Boost Converter for PV Application Using Si and SiC Devices

Grid-connected photovoltaic (PV) inverters have a dc/dc converter connected to the PV for executing the maximum power point tracking. The design of an interleaved boost converter (IBC) with three switching legs for a 10-kW PV inverter is presented in this paper. This paper shows how the use of silicon carbide (SiC) switches and powdered iron core inductors enables the operation of the converter at a higher switching frequency and when increasing the converter power density. The IBC is designed using a 1.2-kV SiC MOSFET and Schottky diodes and Kool Mμ powdered iron inductors. The design is compared with an IBC built with a silicon (Si) IGBT, fast recovery Si diodes, and ferrite cores. The use of SiC devices reduces the switching loses drastically and there are no reverse recovery losses, resulting in improved efficiency. The higher frequency and higher saturation flux density of the powdered iron core enable the reduction in core size by three times. A 10-kW prototype is built and tested for both the Si and SiC designs and compared with theoretical estimations.

Implementation of minimisation techniques to construction optimisation of iron‐core inductor

In this study, the authors propose a modelling algorithm of inductors that provides a powerful tool for solving a variety of engineering optimisation problems. The algorithm has been developed in accordance with desire to consolidate cost benefit, losses minimisation and inductance maximisation, and finding the best manufacturing solution. A non-linear mathematical model for optimisation of three-phase, dry type double-E iron-core inductor has been presented in this study. Its purpose is to show that design of three-phase, air-cooled, network frequency inductors can be obtained using of new, adopted non-linear modelling algorithm-MISP (mixed-integer signomial programming), for minimising cost of materials (or inductor's mass) while ensuring the satisfaction of inductance value together with constraints imposed by overall measures, copper fill factor, maximum allowed induction, current density and temperature rise. The MISP is solved using branch-and-bound approach, specially implemented to inductor design problems. To confirm the result obtains by optimisation, inductor has been constructed according to the minimum loss criterion. The application is industry acceptable in cases if there are restrictions on the inductor weight. Also, where core dimensions are known, this approach can be used to design inductor by either maximising the inductance value or minimising total losses.

Different Techniques for Calculating Apparent and Incremental Inductances using Finite Element Method

This work focuses on using two-dimensional finite element method to calculate apparent and incremental inductances for 40W fluorescent lamp ballast with different loading conditions based on its design documents. Seven inductance calculation techniques are adopted by calculating ballast stored magnetic energy and flux linkage using ANSYS software. The calculated results for apparent inductances show a good agreement with the design and average measured values, while calculated incremental inductances have been verified by noting the behavior of core hysteresis loop experimentally. These seven techniques establish a good base for researchers and designers to obtain an accurate inductance profile for any iron-core inductor.

An Integrated Harmonic-Filtering Transformer for Low-Voltage Distribution Systems

In order to deal with the increasingly harmonic problems caused by nonlinear loads and the consequent distribution transformer noise problems in low-voltage distribution systems, a harmonic-filtering distribution transformer applied in the 10/0.38kV box-type substations is designed and fabricated. As a result, the passive harmonic filters are contained and installed in the substations to work together with the existing distribution transformers. However, due to the space and size physically confined in the substations, it is unsuitable to use air-core reactor based filters because of the large volume and electromagnetic interference. Therefore, PPFs with iron-core reactors are generally taken into account. However, there are undesired impacts on the filtering performance of them, affected by magnetic saturation in iron-core inductors, and serious noise pollution, caused by vibration, as the iron-core inductors operate in various conditions. In this paper, a new-type distribution transformer with filtering inductors integrated is presented, attempting to improve the situations described above.

Proposed Inductor Design for High Speed Digital Communication Systems through Divergence Analysis of Self Inductance and Variability in Permeability Values of Unaltered Human Hair

The Dielectric Losses associated with inductors play more considerable role at higher frequencies. Parasitic capacity determines the magnitude of these losses. The permeability is one of the factors that affect self-inductance of a solenoid directly. Change of medium from free space to any other element like iron or plastic may change the behavior of solenoid. Human hair is primarily composed of keratin. Keratin is considered as a good insulator. However an electric charge gained by the hairs due to friction and this phenomenon is called tribo-electric effect. It gives hair an ability to become charged with static electricity. The scenario tested with coils is wrapped around human hairs and the air between them as a medium. It is hypothesized that replacement of iron by human hair will vary the self-induction. The reference or test validation platform for the experiment was an air and iron core inductor. The reason behind this choice was its wide use in various applications like power supplies, metal detectors, car ignition coils and even in high speed digital systems. The observed values of induced e.m.f for the scenario are used to analyze the deviation in self-Inductance phenomenon. The theoretical model for the air and iron core solenoid is also compared with the resulting values to calculate and reaffirm the permeability values of the human hair especially for South Asian ethnic region.

A Vector Play Model for Finite-Element Eddy-Current Analysis Using the Newton-Raphson Method

The differentiation of the vector hysteretic function represented by a vector play model is discussed for efficient nonlinear electromagnetic field computation using the Newton-Raphson method. The combination of the nonlinear finite-element method and the vector play model achieves accurate representation of the AC anisotropic magnetic property of nonoriented silicon steel sheet under rotational magnetic flux conditions. The proposed method is successfully applied to the eddy-current analysis of iron-cored inductors excited by a current or voltage source.

New Behavioral Modeling for DC Motor Armatures Applied to Automotive EMC Characterization

This paper presents a high-frequency modeling method of direct current motor armatures dedicated to low-voltage automotive applications. The proposed model is based on a behavioral approach, which permits to reproduce impedance measurements. It takes into account some physical features and phenomena related to the motor armature. The influence of the skin effect in the windings, the magnetic field penetration in the core, and the armature manufacturing systematic error in the impedance evolution is considered with this model. The model was first developed from that of a basic iron core inductor and improved afterward in order to cover a high frequency range (from dc up to 1 GHz). Several identification methods were used to quantify the model parameters. Furthermore, the model was associated to a noise-current generator in order to estimate the conducted disturbances. These last ones are emitted by the motor in the RF range (100 kHz-108 MHz), knowing the operating conditions of current intensity, voltage, and speed.

Grain boundary effect on the β-boron electrical transport properties at high pressure

Using a diamond anvil cell, the variable-frequency alternate current impedance spectrum of β-boron has been measured upon increasing the pressure from 3.2 to 27.5 GPa. The analysis has established that both the bulk resistance and the grain boundary resistance of β-boron smoothly decrease with the pressure, and that a remarkable phenomenon of discontinuity occurs at 23.9 GPa; this critical value has been interpreted as the pressure threshold above which the van der Waals forces and the interactions between the β-boron grain boundaries significantly emerge. Thence, the grain boundary contribution to the total resistance dramatically declines and results in an enhanced conduction. Besides, the β-boron sample impedance imaginary part exhibits a typical iron-core inductor frequency characteristic.

Experimental Evaluation of AC Losses of a DC Restive SFCL Prototype

A DC resistive SFCL consists of an inductance and a quenching superconducting resistance embedded in diode bridge. The superconductor operates in nearly DC current conditions. This regime of operation drastically reduces the AC losses and makes it possible to implement the device by means of present state of the art superconductors. In this paper the AC losses of a laboratory scale prototype of DC resistive SFCL (a 200 V/60 A) are experimentally investigated. The prototype consists of a non inductive Bi2223 winding series connected with a conventional iron core inductor and embedded in a diode rectifier which is connected to the protected circuit. The AC losses are measured and compared with those occurring in pure AC operation at the same current.

Stability Analysis of Three-Phase PWM Converter with LCL Filter by Means of Nonlinear Model

In this paper the stability problem of the three phase PWM converters with LCL filter without additional passive or active damping is analyzed. The system with the converter current feedback is considered where the stability problem is more acute. The analysis is performed using two theoretical methods, the discrete z-domain root locus technique and the nonlinear model simulation. The system with two different LCL filters is considered, one with the iron core inductors and the other with the air core inductors. In that way the influence of the iron losses on the system stability is investigated. It is shown that the stability margins obtained by means of the nonlinear model simulation are somewhat wider than the ones obtained by the root locus technique. The theoretical results are validated by the measurements performed on a 40 kW laboratory setup.