Showing papers on "Magnetic core published in 2019"

Additive manufacturing of soft magnetic materials and components

Abstract: Additive manufacturing of soft magnetic materials and components based on laser powder bed fusion (L-PBF) offers new opportunities for soft magnetic core materials in efficient energy converters. For more favorable material compositions like FeSi6.7 (strategy 1) with larger electrical resistivity and close-to-zero magnetostriction a maximum permeability of μmax = 31,000, minimum coercivity of Hc = 16 A/m and hysteresis losses of 0.7 W/kg at 1 T and 50 Hz have been realized. To further reduce eddy current losses significantly, novel topological structures like inner slits (strategy 2) and multilayered structures of alternating layers of electrically insulating material and soft magnetic material (strategy 3) are suggested. Feasibility, functionality and potential of the different strategies (and combinations thereof) are discussed based on first prototypes and supporting simulations. The results are compared to conventional electrical steel and SMC (soft magnetic composites).

Principle and Analysis of Doubly Salient PM Motor With Π-Shaped Stator Iron Core Segments

Abstract: This paper investigates a novel three-phase doubly salient permanent magnet (DSPM) motor. Because of the adoption of Π-shaped stator iron core segments, the asymmetrical magnetic circuit among different phases occurring in conventional DSPM motors with E-shaped stator iron core segments can be avoided, so that balanced and sinusoidal three-phase PM flux linkage and no-load electromotive force (EMF) can be achieved. First, based on a 12/7 stator/rotor pole combination, the operation principle of Π-core DSPM motor is discussed using the least magnetic reluctance principle. Then, the general airgap field modulation theory is extended to the Π-core DSPM motor for explaining its operation principle further and armature winding connection. The finite element analysis is used to validate theoretical analysis, as well as to calculate its electromagnetic performances. The results show that the 12/7-pole Π-core DSPM motor possesses higher average torque output capability and lower torque ripple compared with the 12/8-pole E-core counterpart. Finally, a 12/7-pole Π-core DSPM motor is built and tested so as to experimentally verify the theoretical analysis.

High- Q Three-Dimensional Microfabricated Magnetic-Core Toroidal Inductors for Power Supplies in Package

Abstract: The integration of power inductors is a roadblock in realizing highly miniaturized power supply in package (PSiP) and power supply on chip. Inductors in such power systems are used for energy storage and filtering, but they dominate in size and loss. This paper presents a novel three-dimensional in-silicon through-silicon via (TSV) magnetic-core toroidal inductor for PSiP. The magnetic powder based core is embedded into a TSV air-core inductor using a casting method. The unique air-core inductor design with a hollow core and suspended windings enables a complete core filling with microscale magnetic powders. The proposed casting method is simple, scalable, and generic for a wide range of magnetic powders. TSV magnetic-core inductors are fabricated in a compact size of 2.4 mm × 2.4 mm × 0.28 mm with the core content varying from 63 to 88 wt% of soft ferrite NiZn powders. The TSV magnetic-core toroidal inductors are fabricated and electrically characterized. Small-signal measurements show a threefold higher inductance of 112 nH and a 30% higher quality factor of 14.3 at 12.5 MHz for magnetic-core inductors compared with similar TSV air-core inductors. The small-signal measurement results are verified by the modeled results. The total core loss is characterized by large-signal measurements. A suitable inductor is implemented in a 12-MHz buck converter that operates in a zero-voltage-switching mode. The converter achieves a peak efficiency of 71.6% and an output power of 2.4 W while converting 12 to 5 Vdc.

A Simple and Efficient Quasi-3D Magnetic Equivalent Circuit for Surface Axial Flux Permanent Magnet Synchronous Machines

Abstract: This paper presents a simple and efficient magnetic equivalent circuit (MEC) model for surface axial flux permanent magnet synchronous machines. The MEC model is used to solve all the electromagnetic properties of the machine including the no load, full load voltages, cogging torque, torque ripple, and stator iron core losses. Moreover, this approach can be extended for all surface permanent magnet synchronous machines. The main novelty of this approach is the development of a static system, which accounts for the rotation. The model takes into account the rotor rotation via time-dependent permanent magnet magnetization sources. The static system matrix facilitates a very fast solving. In addition, to take into account the three-dimensional (3-D) effect, a multislicing of the machine in the radial direction is done. This boosts the simulation time to only 60 s for six slices and 50 time steps including the nonlinear behavior of the stator elements with a great accuracy. Additionally, the number of elements in the MEC can be adjusted to reduce the computational time. This model is verified by means of 3-D and two-dimensional (2-D) multislice finite-element models. In addition, experimental validations are also provided at the end.

Modeling, Magnetic Design, Simulation Methods, and Experimental Evaluation of Various Powder Cores Used in Power Converters Considering Their DC Superimposition Characteristics

Abstract: Powder cores have been gaining much attention as one of the attractive magnetic cores used in power converters due to their superior features such as high saturation flux density and their capability to suppress fringing flux due to the distributed airgaps. However, powder cores have a unique feature that the relative permeability of the magnetic core varies depending on the magnetic field intensity. The comprehensive modeling of variable relative permeability, design method of powder cores, and computer simulation methods are not well discussed in the relevant literature. This paper proposes a novel modeling, magnetic design method, and simulation technique considering dc superimposition characteristics of powder cores. The modeling method relies on a simple novel model equation representing the behavior of the variable relative permeability under the dc current superimposition condition, which is helpful to evaluate the performance of powder cores and to properly design various magnetic components. In this evaluation, five different magnetic powder cores are used to show the accuracy and properness of the proposed method. Theoretical analysis has been presented and the effectiveness of the proposed methods has been evaluated through simulation and experimental tests.

Study on Vibration of Iron Core of Transformer and Reactor Based on Maxwell Stress and Anisotropic Magnetostriction

Abstract: In this paper, the magnetostrictive orthogonal calculation method is used to simulate the vibration of iron cores of the transformer and shunt reactor models. The two models have the same size except there is a 2 mm air gap in the middle core of the reactor model. The Maxwell stress and total stress on the two cores are quantitatively calculated. The calculated results show that the air gap has a great influence on the vibration of the shunt reactor core. The Maxwell stress is the main reason for the vibration of the reactor core, but the vibration of the transformer core is mainly caused by magnetostriction. Finally, the experimental platform is built to measure the vibration accelerations of the two models and verify the results of the simulation.

Hybrid Dynamical Model for Reluctance Actuators Including Saturation, Hysteresis, and Eddy Currents

Abstract: A novel hybrid dynamical model for single-coil, short-stroke reluctance actuators is presented in this paper. The model, which is partially based on the principles of magnetic equivalent circuits, includes the magnetic phenomena of hysteresis and saturation by means of the generalized Preisach model. In addition, the eddy currents induced in the iron core are also considered, and the flux fringing effect in the air is incorporated by using results from finite element simulations. An explicit solution of the dynamics without need of inverting the Preisach model is derived, and the hybrid automaton that results from combining the electromagnetic and motion equations is presented and discussed. Finally, an identification method to determine the model parameters is proposed and experimentally illustrated on a real actuator. The results are presented and the advantages of our modeling method are emphasized.

Integrated Matrix Transformer with Optimized PCB Winding for High-Efficiency High-Power-Density LLC Resonant Converter

Abstract: Both server and telecom power supply prefers LLC resonant converter with matrix transformer as DC/DC stage due to its high efficiency and high power density. With reduced labor intensive and lower profile, print circuit board (PCB) winding based matrix transformer is gaining more and more attention. A 4 layer PCB structure, with two layers for secondary side winding and another two layers for primary side winding, is general practice. In the case with even number of turns in primary side, each layer has half of the turns. However, with odd number of turns in primary side, it is impossible to physically get half of one turn. This paper proposes a novel winding structure that allows odd number of turns arranged in two layer PCB. Besides, four elemental transformers are integrated into a single planar magnetic core by flux cancellation. The winding width and core dimension are optimized to achieve lower loss and footprint. A 3 kW matrix transformer with 4 layer PCB winding is built up. Turns ratio of 3:1 is demonstrated as an example in each elemental transformer. The proposed winding layout method has simple structure, but shows low winding loss and good current sharing. The matrix transformer is demonstrated on a 500 kHz switching frequency wide band-gap device based LLC resonant converter. The prototype achieves a peak efficiency of almost 98.5% and a power density of 24.4 kW/L (400 W/in3).

Investigation on Power Dissipation in the Saturated Iron-Core Superconducting Fault Current Limiter

Abstract: This paper presents the power dissipation analysis on saturated iron-core superconducting fault current limiter (SISFCL). The modeling of SISFCL together with its power dissipation computation on a high-temperature superconducting (HTS) coil was executed by the H-formulation model implemented into the finite element method (FEM) software package COMSOL. The model was based on the practical three-phase 35-kV/90-MVA SISFCL. The ac magnetic field in the crucial parts of SISFCL was studied to discover the origin of power loss on the HTS coil. The instantaneous power dissipations in the HTS coil with increasing dc bias current were computed and compared. Analysis proved that power dissipation in the HTS coil of SISFCL should be taken into account for the real operation.

A Novel Reluctance Magnetic Gear for High-Speed Motor

Abstract: Magnetic gears are expected to be a maintenance-free system with low-noise and low-vibration characteristics by a noncontact power transmission. However, conventional magnetic gears are not suitable for use with high-speed motors because the mechanical strength is weak due to the use of permanent magnets in a high-speed rotor. Additionally, the magnet eddy current losses in the high-speed rotor seriously decrease the gear's efficiency during a high-speed operation. This paper presents a novel reluctance magnetic gear that can realize the high-speed drive and high efficiency. The high-speed rotor of the proposed magnetic gear is constructed by only an iron core. Therefore, the structure is very simple and robust, adding that it is possible to rotate in the high-speed region. Moreover, the proposed magnetic gear achieves high efficiency in the high-speed region because the magnet eddy current loss in the high-speed rotor is not generated because no magnets are used. The downsizing of the system and a high efficiency power transfer are realized by applying the proposed reluctance magnetic gear.

High-efficiency, High-density Isolated/Regulated 48V Bus Converter with a Novel Planar Magnetic Structure

Abstract: In this paper, an LLC converter utilizing gallium nitride (GaN) transistors is proposed for a 48V regulated and isolated bus converter. Compared to pulse width modulation (PWM) based topologies, the soft switching capability of an LLC allows operation at very high frequencies. In addition, the magnetic components size is reduced without sacrificing efficiency. A novel magnetic structure that integrates a matrix transformer and inductor with the same winding and magnetic core is proposed in this work, to allow a high-density and high-efficiency LLC converter design for a bus converter. A 40V-60V input and regulated 12V output converter is developed to deliver a 1 KW output power in a quarter brick form factor. The designed converter can achieve a power density of 700 W/in3 with a maximum efficiency of 97.82% at half load, dropping to 97.7% at full load operation.

An efficient equalizing method for lithium-ion batteries based on coupled inductor balancing

Abstract: This article developed a coupled inductor balancing method to overcome cell voltage variation among cells in series, for Lithium Ion (Li-ion) batteries in Electrical Vehicles (EV). For an "eight cells in series" example, the developed balance circuit has four inductors, one magnetic circuit with one winding per two cells, and one control switch per cell, as compared to the traditional inductor-based equalizer that needs N-1 inductors and magnetic circuits for N number of cells and more switches. Therefore, ultimately, a more efficient, cost-effective circuit and low bill of materials (BOM) will be built up. All switches are logic-level N-Channel metal-oxide-semiconductor field-effect transistors (MOSFETs) and they are controlled by a pair of complementary signals in a synchronous trigger pattern. In the proposed topology, less components and fast equalization are achieved compared to the conventional battery management system (BMS) technique for electrical vehicles based on the inductor balancing method. This scheme is suitable for fast equalization due to the inductor-based balancing method. The inductors are made with a well-chosen winding ratio and all are coupled with one magnetic core with an air gap. Theoretical derivation of the proposed circuit was well-presented, and numerical simulation relevant to the electrochemical storage devices was conducted to show the validity of the proposed balance circuit. A complete balance circuit was built to verify that the proposed circuit could resolve imbalance problems which existed inside battery modules.

A Ćuk Converter Cell Balancing Technique by Using Coupled Inductors for Lithium-Based Batteries

Abstract: In this paper, a cuk converter balancing method by using a coupled inductor for lithium based batteries is investigated. The proposed circuit is an active balancing circuit that will equalize eight battery cells in a series. In electrical vehicles (EV), a battery management system (BMS) is a vital task to achieve the best performance of the batteries and longer lifetime. The problem of voltage difference in a battery pack is an important issue to be improved. To overcome the voltage differences in battery string, an equalizing method is mandatory. The conventional cuk converter requires 2(n-1) switches to balance n cells, while the proposed circuit requires only n switches for n cells in series. In addition, the proposed developed topology uses coupled inductors instead of un-coupled inductors, unlike the traditional cuk converter balancing method. Since the cuk balancing transfers the energy among two adjacent cells, it requires a proportionately long equalization time particularly for long string battery packs, but the coupled inductor cuk converter type overcomes this problem. The switches are N-channel metal-oxide field-effect transistor (MOSFET) to achieve lower drain-source on-resistance, RDS(on), and less voltage drop as compared to the P-channels. The switches are triggered by complementary signals. The coupled inductor is made in such a way to hold the same magnetizing inductance. It can be done by using five wires in one hand. The circuit contains five inductors, one magnetic core, with five winding for eight cells, and one capacitor for two cells. Therefore, the overall circuitry and complexity of the circuit are reduced, resulting in a more cost-effective and easy to implement circuit. The system also does not demand complicated control for battery equalizing. The experimental circuit was implemented and simulation results were obtained to confirm the validity of the proposed system.

Modified Series and Tapped Switched-Coupled-Inductors Quasi-Z-Source Networks

Abstract: This paper proposes two coupled-inductors-based Z-source networks, called the modified series and tapped switched-coupled-inductors quasi-Z-source networks (mSSCL-qZSN and mTSCL-qZSN, respectively). These networks offer high voltage gains with less-than-unity winding turn ratios $(n , resulting in a reduced inductive element size. Other advantages include a less number of active components and their lower ratings and a higher efficiency. In addition, a lower magnetic core size is required for the proposed ZSNs due to the lower peak magnetizing current. The performance principles and detailed comparative analysis are provided and confirmed through experiments on a 200-W dc–dc converter.

Dynamic magnetic characterization and magnetic particle imaging enhancement of magnetic-gold core-shell nanoparticles.

Abstract: Multifunctional nanoparticles with a magnetic core and gold shell structures are emerging multi-modal imaging probes for disease diagnosis, image-guided therapy, and theranostic applications. Owing to their multi-functional magnetic and plasmonic properties, these nanoparticles can be used as contrast agents in multiple complementary imaging modalities. Magnetic particle imaging (MPI) is a new pre-clinical imaging system that enables real-time imaging with high sensitivity and spatial resolution by detecting the dynamic responses of nanoparticle tracers. In this study, we evaluated the dynamic magnetic properties and MPI imaging performances of core-shell nanoparticles with a magnetic core coated with a gold shell. A change in AC hysteresis loops was detected before and after the formation of the gold shell on magnetic core nanoparticles, suggesting the influence of the core-shell interfacial effect on their dynamic magnetic properties. This alteration in the dynamic responses resulted in an enhancement of the MPI imaging capacity of magnetic nanoparticles. The gold shell coating also enabled a simple and effective functionalization of the nanoparticles with a brain glioma targeting ligand. The enhanced MPI imaging capacity and effective functionality suggest the potential application of the magnetic-gold core-shell nanoparticles for MPI disease diagnostics.

A 3-D Topology Optimization of Magnetic Cores for Wireless Power Transfer Device

Abstract: This paper presents the topology optimization of the magnetic core for a wireless power transfer (WPT) device. In this optimization, the coil and magnetic-core shapes for WPT are represented by the Gaussian basis functions. They are sequentially optimized using the genetic algorithm and 3-D finite-element analysis so that the coupling coefficient of the WPT device is maximized. Moreover, a robust optimization method is proposed to keep the interlinkage flux as large as possible against misalignment in the coils. It is shown by the computational and experimental results that the optimized device outperforms the conventional devices.

Electromagnetic Performance Analysis of Consequent-Pole PM Machine With Asymmetric Magnetic Pole

Abstract: The permanent magnet (PM) machine with consequent-pole (CP) rotor can improve the PM utilization ratio. However, the replacement of the PMs with the same polarity by the salient iron core deteriorate the electromagnetic performance of the machine, including higher torque ripple and unipolar leakage flux. Therefore, a CP PM machine with asymmetric magnetic pole (AMP) structure is proposed, through which the smaller torque ripple and unipolar leakage flux can be obtained, without deteriorating the torque characteristics compared with the traditional CP PM machine. Furthermore, the electromagnetic performance and the unipolar end leakage flux of the AMP and traditional CP PM machines are investigated by the finite-element method (FEM). It is demonstrated that AMP structure can reduce the cogging torque and torque ripple; furthermore, the unipolar leakage flux can be suppressed effectively. Finally, the prototype with AMP and CP PM rotor are fabricated and tested to verify the theoretical and FE analysis.

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

Abstract: 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.

FeNi nanotubes: perspective tool for targeted delivery

Abstract: Targeted delivery of drugs and proteins by magnetic field is a promising method to treat cancer that reduces undesired systemic toxicity of drugs. In this method, the therapeutic agent is attached through links to functional groups with magnetic nanostructure and injected into the blood to be transported to the problem area. To provide a local effect of drug treatment, nanostructures are concentrated and fixed in the selected area by the external magnetic field (magnet). After the exposure, carriers are removed from the circulatory system by magnetic field. In this study, Fe20Ni80 nanotubes are considered as carriers for targeted delivery of drugs and proteins. A simple synthesis method is proposed to form these structures by electrodeposition in PET template pores, and structural and magnetic properties are studied in detail. Nanotubes have polycrystalline walls providing mechanical strength of carriers and magnetic anisotropy that allow controlling the nanostructure movement under the exposure of by magnetic field. Moreover, potential advantages of magnetic nanotubes are discussed in comparison with other carrier types. Most sufficient of them is predictable behavior in magnetic field due to the absence of magnetic core, low specific density that allows floating in biological media, and large specific surface area providing the attachment of a larger number of payloads for the targeted delivery. A method of coating nanotube surfaces with PMMA is proposed to exclude possible negative impact of the carrier material and to form functional bonds for the payload connection. Cytotoxicity studies of coated and uncoated nanotubes are carried out to understand their influence on the biological media.

A Soft-Switching Non-Inverting Buck–Boost Converter With Efficiency and Performance Improvement

Abstract: This letter proposed a new soft-switching non-inverting buck–boost converter (NIBBC) by introducing the magnetic coupling effect to an existing soft-switching dc/dc converter. The new NIBBC obtains two superiorities: one magnetic core is removed to improve the efficiency; the magnetic coupling effect can give an adjustable soft-switching range. Operating principles and converter characteristics of the new NIBBC are presented. An experimental prototype of the new NIBBC is built, and switching waveforms and the efficiency are measured. Experimental results show that the new NIBBC can obtain soft-switching conditions and has efficiency improvement comparing to hard-switching converter and another soft-switching dc/dc converter.

Analytical Prediction of Iron-Core Losses in Flux-Modulated Permanent-Magnet Synchronous Machines

Abstract: In this paper, an analytical approach allowing the prediction of iron-core losses in flux-modulated permanent-magnet synchronous machines. According to the Maxwell–Fourier method (viz., the multi-layer model) and Cauchy’s product theorem, the magnetic field distribution is determined in different parts of machine by considering the iron permeability on the basis of solving both Poisson’s and Laplace’s equations. Next to the dc bias flux density and the minor hysteresis loops, which are taken into account, the Bertotti’s model and the flux variation locus are employed to calculate the iron-core losses under load and no-load conditions in post-processing from the magnetic field analytical calculation. Finally, in order to validate the proposed analytical method, the results are verified by the comparison with the finite-element method. The comparisons show good results of the proposed model.

8.5 A Fully Integrated Voltage Regulator in 14nm CMOS with Package-Embedded Air-Core Inductor Featuring Self-Trimmed, Digitally Controlled Variable On-Time Discontinuous Conduction Mode Operation

Abstract: Fully Integrated Voltage Regulators (FIVR) with package-embedded air-core inductors [1] or on-die solenoid inductors with planar magnetic core [2] promise efficient power delivery and fine-grain wide-range DVFS in complex SoCs while providing fast transient response. The FIVR must provide high conversion efficiency across a wide operating range of output voltages and load currents, including light to medium loads, to maximize the overall energy efficiency of the SoC across different power states. Phase shedding and switch scaling have been used for high-frequency FIVR designs with pulse-width modulation (PWM) control in continuous conduction mode (CCM) to maintain high efficiency for large load currents [1–5], and pulse-frequency modulation (PFM) and hysteretic control have been used to achieve high efficiency across light to medium loads [3–5]. In this paper, we present an FIVR in 14nm CMOS with a 2.5nH air-core inductor embedded in an ultrathin coreless package $( 200 \mu m$ thick) (Fig. 8.5.7), featuring self-trimmed, soft-switched and digitally controlled variable ON-time DCM operation up to 70MHz to achieve high conversion efficiencies across light to medium load currents ranging from 5mA to 500mA and wide 0.7-1.2V output voltage range. The FIVR uses a cascoded thin-gate powertrain (Fig. 8.5.1) to support input voltages up to 2Vmax with the cascode bias rail set at $V_{in} /2$ which consumes $\lt/p\gt\lt1$ uA at light load. A small thick-gate device is connected across the inductor to dampen oscillations when the power stage is in a high-impedance state. The output voltage is monitored by a comparator with sub-ns response time which triggers an inductor current pulse when the output drops below the reference voltage. A resistor divider with a feedforward capacitor is used to achieve fast response time.

Soft-Switching Voltage-Demultiplier-Cell-Based High Step-Down DC–DC Converter

Abstract: A novel high step-down dc–dc converter with voltage demultiplier cell is proposed in this paper, which is widely used in the high step-down applications such as electric vehicle and digital circuits. The combination of switched-capacitor and coupled-inductor is employed to build extended voltage demultiplier in the proposed converter, which makes a quite higher voltage conversion ratio than that of the existing counterparts. Thus, the proposed converter can achieve extremely low output voltage with an appropriate duty ratio, and the extreme duty cycle is avoided. Accordingly, voltage stress on power switches is greatly reduced. Then, mosfet s with low conduction resistance could be utilized to reduce conduction loss. Importantly, zero-voltage switching could be achieved for the main switch, which promotes the conversion efficiency further. In addition, the coupled inductor operates not only as a filter inductor, but also as a transformer when the main switch is in the off state, which reduces the volume of the magnetic core and improves the power density of the converter. The operation principle, performance analysis, design considerations of the proposed converter and performance comparison with recent counterparts are discussed in detail, and finally, an experimental prototype is built to verify the theoretical analysis and performance of the proposed converter.

A new type of DC superconducting fault current limiter

Abstract: A new type of Superconducting Fault Current Limiter (SFCL) for dc applications is proposed. This SFCL consists of a current transmission/limiting coil, an iron-core, and a set of superconductor rings. The superconductor rings are placed between the current transmission/limiting coil and the iron-core. For application, the current transmission/limiting coil is connected in series to a dc transmission line. During normal power transmission, magnetic flux coupling between the current transmission/limiting coil and the iron-core is prevented by the magnetic shielding of the superconductor rings, and the current transmission coil has low impedance. Because of shielding effect of the superconductor rings iron-core has high permeability at the beginning of short circuit, current-limiting coil can effectively limit fault current rise. When the fault current reaches a certain level, the superconductor rings will quench and the shielding effect is greatly reduced. The current-limiting coil strengthens the coupling with the iron core, increases the inductance, and will suppress the further increase of the fault current. A laboratory proof-of-concept prototype was made to demonstrate the feasibility of the idea. Experiments have been carried out with the prototype. In this paper, we will introduce the detailed information of the principle, the prototype, and the experimental results. In addition, a design of the new type of dc SFCL is installed in a ±160 kV high-voltage direct current system.

Direct-write printed broadband inductors

Abstract: 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.