Integration Of Inductors Research Articles

Inductor integration for internal parallel inverters

SummaryIn addition to inheriting the merits of interleaved parallel inverters, the internal parallel structure (IPS) inverter has the advantages of reduced circulating current and lower switching loss. Currently, however, the suppression of circulating current and output current ripple individually results in an evident increase in the number and volume of inductors. In this work, an inductor integration scheme is developed to improve the IPS inverter. Two integrated inductors are developed for different application configurations. As a result, the circulating current and output current ripple are simultaneously suppressed by an integrated inductor, making each phase of the IPS inverter to be equipped with only one integrated inductor implemented by wounding two coils on one magnetic core. The feasibility of the inductor integration scheme for the IPS inverter is experimentally verified by a downscale prototype.

Single magnetic core based inductor integration for battery-friendly LCL-type interleaved interface

Interleaving operation of the two-phase Buck/Boost converter is beneficial for reducing current ripple and power sharing. It makes this converter considered an ideal battery interface. However, multiple inductors are required in this power interface. To overcome this issue, an inductor integration scheme is developed in this work to optimize the two-phase Buck/Boost converter. With this design, all inductors required in the converter are implemented by wounding three coils on one magnetic core, which effectively improves the utilization of magnetic cores and reduces the size and cost of the battery interface. Moreover, both phase current ripple and total current ripple are suppressed by this design. In addition to the design concept, the specific coil wounding scheme, magnetic flux analysis, air gap design, and active damping control are analyzed in detail. Finally, Maxwell simulation model of the integrated inductor and 240 V to 400 V prototype of the two-phase interleaved Buck/Boost converter are developed. Simulation and experimental results effectively verify the effectiveness of the design scheme and the correctness of the theoretical analysis.

Layout Optimization of Integrated Inductors and Capacitors Using TGV Technology

Layout Optimization of Integrated Inductors and Capacitors Using TGV Technology

Enhancing voltage gain and switching efficiency in a non-isolated buckboost converter through integrated switching inductor configuration

This research presents a novel investigation into advancing the operational efficiency and performance of non-isolated buck-boost converters utilized in photovoltaic (PV) systems as charging controllers. The focus of this study lies in the development and integration of a specialized switching inductor configuration, aiming to augment the converter's voltage gain while concurrently mitigating stress imposed on the converter switch. The converter's efficacy is of paramount importance, particularly during stepping-up operations where the duty cycle reduction, a consequence of the integrated switched inductor, contributes to reduced stress. The proposed converter architecture is characterized by its simplicity, necessitating only minimal components for implementation. These include a single capacitor, a pair of diodes, a duo of inductors, and a trifecta of switches. Operating nominally at 12 volts, the converter dynamically adjusts the voltage level in response to varying duty cycles: elevating it beyond the 35% threshold and inversely attenuating it below this parameter. A salient outcome of this endeavor is the curtailment of the dependency on an additional diode (D), resulting in streamlined circuitry. The conceptualized switching inductor model was rigorously assessed using the MATLAB/SIMULINK simulation environment, affording a comprehensive evaluation of its efficacy and robustness. This study thus underscores the viability and potential for significant enhancements in non-isolated buck-boost converter systems through inventive switching inductor integration.

Integrated Inductor Layout Optimization for Synthesis of Microwave LC-Filters in Si/SiGe/GaAs Systems on a Chip

The paper proposes models of planar symmetric octagonal inductors that differ in the method of inductance calculating and consideration of the structure and characteristics of the technological process. The equations in a closed form for calculating models of integral planar inductors of various configurations are derived. The models were verified by comparing the frequency response of the developed 14-18 GHz bandpass filter model with the frequency response of experimental samples produced in the SiGe 130 nm process. The AFC of the produced filter samples is in the range of the developed filter model AFCs at the extreme points of the manufacturing tolerance. The developed algorithm of optimization for integral planar inductors layouts according to the criterion of maximum quality factor at the required frequency is presented. The use of the developed algorithm for integral planar inductors layouts optimization makes it possible to synthesize integrated LC-filters in Si, SiGe and GaAs technological processes with minimal passband losses and maximum gain slopes. The optimization algorithm is implemented as the program in the MathCad software. The optimal inductor layout calculation according to the criterion of maximum quality factor in the program takes tens of seconds a few minutes depending on the technological process structure complexity.

Self-Tuning Multiport Resonant DC/DC Converter Based on Actively-Controlled Inductors for Hybrid Storage System Integration

In the field of electric mobility, in particular heavy-duty electric vehicles and long-haul trucks, the energy systems are susceptible to transients with different amplitudes and dynamics due to the high power demand. With the combination of high power and long distances, the available battery technologies become insufficient as a single energy source for such a system. Thus, the integration of hybrid energy storage systems (HESSs) with different energy capabilities, such as fuel cells, battery packs, and supercapacitors, is highly required. In this context, for leveraging HESSs in an efficient way, a resonant multiwinding transformer-based converter is proposed to interconnect these different energy storage systems (ESSs) since the resonant converters are able to operate at a wider range of switching frequencies and, hence, a wider soft-switching range. However, due to the multiple resonant circuits and possible parameter deviations, the control capability might be compromised. Thus, a multiport resonant dc/dc converter embedded with variable inductors is proposed to enhance the power flow management among these different ESSs with reduced conversion stages. Further, the proposed concept can also improve the immunity to parameter deviations on the resonant by compensating for possible variations at the resonant frequencies. Finally, simulations and experimental results of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{20} \;\text{kW}$</tex-math></inline-formula> four-port resonant dc/dc converter embedded with variable inductors are shown to prove the effectiveness of the proposed concept.

Impact of minor hysteresis loops in integrated inductors with ferromagnetic films

Integration of inductors on silicon chips is becoming more and more relevant for monolithic electronic applications. In this Letter, we investigate the impact of minor hysteresis loops in an integrated inductor with spiral geometry sandwiched between two soft magnetic layers made of MoNiFe/Cr multilayers. Despite high magnetic susceptibility and low coercivity of optimized multilayers, we find that the inductance is strongly dependent on the AC voltage applied to the device, showing a bell-shaped behavior. Comparing the measured inductance with magneto-optical Kerr effect and vibrating sample magnetometry measurements, we show that the low-signal behavior is limited by domain wall pinning/depinning, which determine the effective susceptibility associated with minor hysteresis loops driven by the applied AC voltage.

Radio-frequency circular integrated inductors sizing optimization using bio-inspired techniques

&lt;span lang="EN-US"&gt;In this article, a comparative study is accomplished between three of the most used swarm intelligence (SI) techniques; namely artificial bee colony (ABC), ant colony optimization (ACO), and particle swarm optimization (PSO) to carry out the optimal design of radio-frequency (&lt;/span&gt;&lt;span lang="EN-US"&gt;RF) spiral inductors, the three algorithms are applied to the cost function of RF circular inductors for 180 nm beyond 2.50 GHz, the aim is to ensure optimal performance with less error in inductance, and a high-quality factor when compared to electromagnetic simulation. Simulation experiments are achieved and performances regarding convergence velocity, robustness, and computing time are checked. Also, this paper shows an impact study of technological parameters and geometric features on the inductance and the quality factor of the studied integrated inductor. The building method of constraints design with algorithms used has given good results and electromagnetic simulations are of good accuracy with an error of 2.31% and 4.15% on the quality factor and inductance respectively. The simulation shows that ACO provides more accuracy in circuit size and fewer errors than ABC and PSO, while PSO and ABC are better in terms of convergence velocity.&lt;/span&gt;

Suppression of Eddy Current Loss in Multilayer NiFe-Polypyrrole Magnetic Cores Fabricated Using a Continuous Electrodeposition Process

Metallic magnetic alloys are of interest as core materials in ultracompact or integrated inductors and transformers. However, when operated at high frequencies, such materials should comprise a multilayer stack of magnetic material laminations and electrically insulating interlayers to suppress eddy current loss. To achieve scalable and continuous fabrication of such a structure, sequential multilayer electrodeposition is an attractive approach. To achieve sequential electrodeposition, interlayer’s electrical conductivity should be sufficiently high to permit electrodeposition of subsequent layers, but sufficiently low to suppress eddy current loss. Polypyrrole, an electrodepositable polymer, was investigated as an interlayer material. Finite element modeling demonstrated a negligible difference in eddy current loss between NiFe/polypyrrole and NiFe/vacuum multilayers. Experimental verification of the efficacy was demonstrated as well. Compared with a single-layer NiFe inductor that has a comparable low-frequency (10 kHz) inductance value, a laminated ten-layer NiFe core showed higher inductance retention (88% of the low-frequency inductance for the laminated core versus 21% for the single-layer core) and lower ac resistance (1.68 versus <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$12.7~\Omega $ </tex-math></inline-formula> ) at 8 MHz, both of which are signs of suppressed eddy current. This scalable fabrication approach to high-frequency inductors will facilitate power converter miniaturizations.

Decoupled Magnetic Integration of Symmetrical LCL Filter With a Common-Mode Inductor for Single-Phase Grid-Connected Converters

High-frequency power electronic devices in grid-connected converters excited vast switching harmonics and electromagnetic interference (EMI) noises. Conventional <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> -type harmonic filters can well attenuate switching harmonics, but have a poor EMI suppression capability, especially for common-mode (CM) noise. Symmetrical filter structure and an additional EMI filter are generally needed to effectively suppress EMI in power converters, but this will inevitably increase the size and cost of the output filter. In order to tackle this issue without sacrificing the filter performance, this article proposes a decoupled magnetic integration of symmetrical <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filters with a CM inductor for single-phase grid-connected converters. The harmonic inductors of a symmetrical <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filter and a CM inductor are integrated on the side-limbs and middle-limb of an EE-type magnetic core, respectively. Due to the decoupled magnetic structure and the reasonable assignment of the windings, the magnetic coupling between converter-side inductors and grid-side inductors can be greatly canceled to improve the performance of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filters on the basis of the integration of CM inductor to suppress CM EMI. The detailed design guidance of the proposed integration method is presented. A single-phase decoupled magnetic integration filter is fabricated and tested, and the experimental results verify the effectiveness and feasibility of the proposed method.

Multi-Constraint Optimization and Co-Design of a 2-MHz All-GaN Based 700 W 95.6% Efficient LLC Converter

This paper analyzes and develops a multi-variable &amp; multi-constraint design optimization approach with the goal of minimizing power losses in a 2 MHz LLC resonant converter for next-generation data center applications. For a thorough co- design of a multi-MHz resonant converter, intricately curated performance constraints and associated design-based trade-offs are presented. In addition, accurate characterization, and parametric minimization of the AC resistance by optimal selection of transformer winding configuration, while achieving a controllable leakage flux for the resonant inductor integration into the high frequency planar transformer (HFPT) thereby reducing the effective winding losses by 6%. An all-GaN based 700 W, high power density (6.2 W/cm3) experimental proof-of-concept was built for a conversion from a variable input bus voltage (380–420 V) to 12 V stiff output at a resonant frequency of 2 MHz. The results portrayed a steady state peak efficiency of 95.65%, with an improvement of 2.2% over the state-of-the-art (SOA) operable at MHz frequency

A Low Loss Orthogonal Decoupling Magnetic Integrated Structure for Dual Active Bridge Converter

The volume of magnetic components (transformer and inductor) in a dual active bridge (DAB) converter is a crucial factor determining its power density. This article proposes an orthogonal decoupling magnetic integrated structure (ODMIS) for DAB converter, which aims to reduce the volume of the transformer and inductor. The integrated series inductor and magnetizing inductor do not affect each other in the ODMIS, so the design process of the transformer and inductor can be separated. The condition to realize magnetic circuits decoupling of the transformer and inductor is derived. The loss characteristics of the magnetic core are analyzed, and the optimal decoupling condition to minimize the core loss is also derived. A 400 V/6 kW/20 kHz DAB converter prototype is built to validate the effectiveness of the ODMIS. The measured full-load overall efficiency of the DAB test platform is 97.55%, and the power density of the magnetic integrated components is 10.08 kW/L. Finally, the prototype comparisons between the proposed ODMIS and two existing magnetic integrated structures and discrete magnetic component method are conducted, and the advanced feature of the ODMIS is illustrated.

Package-Scale Galvanic Isolators Based on Radio Frequency Coupling: Micro–Antenna Design

This paper presents the design of on-chip micro-antennas for package-scale galvanic isolators based on RF planar coupling. A step-by-step design procedure is proposed, which aims at the maximization of the weak electromagnetic coupling between the RX and TX antennas integrated on side-by-side co-packaged chips to enable both high isolation rating and common-mode transient immunity thanks to the high dielectric strength and low capacitive parasitics of a molding compound-based galvanic barrier, respectively. Micro-antenna design guidelines are drawn, highlighting the main relationship between coil coupling performance and their layout parameters, which are often in contrast with respect to traditional integrated inductor ones.

An Interleaved High Step-Up DC-DC Converter Based on Integration of Coupled Inductor and Built-in-Transformer With Switched-Capacitor Cells for Renewable Energy Applications

This paper proposes an interleaved high step-up DC-DC converter with the coupled inductor (CI) and built-in transformer (BIT) for renewable energy applications. Two double-winding (2W) CIs and one triple-winding (3W) BIT are integrated with the switched-capacitor (SC) voltage multiplier cells (VMCs) to achieve high-voltage gains without extreme duty cycles. The CIs and BIT turns-ratios provide two other degrees of freedom&#x2014;in addition to the duty cycle&#x2014;to adjust the voltage gain that leads to increased design flexibility. The diodes turn off naturally under the zero-current switching (ZCS) conditions because their current falling rates are controlled by the leakage inductances of the CIs and BIT; therefore, the diodes&#x2019; reverse-recovery problems are alleviated. Moreover, employing passive diode-capacitor clamp circuits, the voltage stresses of the switches are limited to a low value far less than the output voltage. Additionally, the leakage inductances energies are recycled and transferred to the output to further extend the voltage gain. Furthermore, due to the interleaved structure, the input current ripple and current stresses of the components are reduced. The proposed converter is analyzed in detail and then compared with similar converters that employed CIs and/or BIT along with passive/active clamp circuits for the MOSFETs. Finally, to verify the feasibility of the proposed converter, the experimental results of a 200 W prototype with output voltage of 400 V and voltage gain of 25 are presented.

Optimal Design of Fully Integrated Magnetic Structure for Wireless Charging of Electric Vehicles

Optimal design of a fully integrated magnetic structure for electric vehicle (EV) wireless charging is proposed in this article. The proposed approach helps save ferrite material, reduce the implementation cost, shrink the size of the converter, and improve the cost and power density. Typically, in a wireless charging system, an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> resonant network and the receiver dc–dc converter are used, which require a bulky inductor in their structures. The integration of resonant inductor with the transmitter-side coil has been studied in the literature to reduce the overall cost and improve the power density of an EV wireless charger. The integration of the dc–dc inductor with the vehicle-side receiver coil is also introduced in the literature. However, the full integration of both resonant inductor and dc–dc inductor into the transmitter and receiver coils of the wireless charging system creates new design challenges that have not been addressed before. In this article, the proposed fully integrated magnetic structure and its design challenges are studied in detail. A procedure for achieving the optimal design of the fully integrated structure is presented. An optimization problem is defined to design the best magnetic structure and select the best values for the resonant elements and dc–dc inductor. The outcome of this integration is an all-integrated magnetic structure, compact converter, and efficient wireless charger. A 2.2-kW/85-kHz system is built to verify the feasibility of the proposed integrated wireless charging system, and its performance is evaluated through the experiment.

An Integration Method of Resonant Switched-Capacitor Converters Based on Parasitic Inductance

The parasitic inductor can be used as resonant component to increase the power density in resonant converters. However, the parasitic inductance value of PCB copper traces is not large enough to achieve zero current switching in low and medium switching frequency conditions. To tackle this problem, a novel integration method to increase parasitic inductance value is proposed in this letter. The proposed method is based on direct coupling, which utilizes lateral structure and vertical structure to increase equivalent inductance between two parasitic inductors. The proposed method not only can achieve high efficiency, high power density, and very low profile design, but also can save the cost and space of discrete inductors for the designed prototype in low and medium frequency range. The comparison and design procedure of both lateral and vertical structures of the parasitic inductor are presented in details. Two 100-W prototypes employing gallium nitride devices are built to compare the discrete inductor solution with the proposed parasitic inductor integration method. The power density of the prototype using parasitic inductor is 62.5% higher than discrete inductance and has achieved a peak efficiency of 93.4%.

Fully Integrated Switched-Inductor-Capacitor Voltage Regulator With 0.82-A/mm2 Peak Current Density and 78% Peak Power Efficiency

Fully integrated voltage regulators (FIVRs) can improve the performance and reduce the power consumption of a system-on-chip (SoC) by providing point-of-load voltage regulation with dynamic voltage scaling. The desirable attributes of FIVRs include high power efficiency, high power density, and fast transient response, which are difficult to achieve due to on-chip area constraint and parasitic effects. Low-quality and low-density on-chip inductors and capacitors are currently the main performance-limiting factors. This article presents a switched-inductor-capacitor (SIC) voltage converter that can operate more efficiently with compact on-chip air-cored metal-tracked inductors than existing step-down voltage converters. The SIC converter consists of an inductor, a flying capacitor, and three power switches, and it can provide fine-grained voltage regulation by using pulsewidth-modulation (PWM) control. The unique SIC converter topology eases the on-chip inductor integration by positioning the inductor at the input power supply and reducing the current stress of the inductor. A proof-of-concept fully integrated SIC voltage regulator is fabricated in a 65-nm CMOS process, with an area of 1.3 mm × 0.5 mm excluding pads. The output voltage can be regulated from 0.6 to 0.9 V given a 1.2-V input power supply. The output voltage ripple is below 56 mV over the entire range of output voltages and load currents. The peak power efficiency is 78% at an output of 0.9 V and 406 mA. The peak power density is 730 mW/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , and the peak current density is 820 mA/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Inductance Model of a Backside Integrated Power Inductor in 2.5D/3D Integration

Inductor integration is of vital importance for miniaturization of power supply on chips. In this paper, a backside integrated power inductor is presented. The inductor is placed at the backside of a silicon interposer and connected to the front side metal layers by through-silicon vias (TSVs) for area saving and simple fabrication. An inductance model is proposed to effectively capture the total inductance of the power inductor by an analytical method. The results obtained from the analytical model and finite element method exhibit good agreement with various design parameters and the error between the proposed model and measurement remains less than 7.91%, which indicates that the proposed model can predict the inductance suitably.

Phase shift control dual active bridge converter with integrated magnetics

Traditional dual active bridge converters use transformer leakage inductance instead of energy storage inductors for magnetic integration, but this method cannot accurately control the leakage inductance. A phase shift control dual active bridge converter base on integrated magnetics is proposed, in which one transformer and one inductor are integrated in an EE core. The size of the inductance can be accurately controlled. The transformer and the inductor are decoupled and integrated so that the two operating states do not affect each other. The weight and volume of the magnetic elements are reduced accordingly. The finite element analysis and magnetic circuit simulation of the integrated magnetics are carried out. Finally, the integrated magnetics are designed and applied to the 600W prototype to realize bidirectional power transmission and a weight reduction is about 36.24% and a volume reduction is about 35.84%. The correctness of the design is verified by experimental results.

Development of a Highly Densified Magnetic Sheet for Inductors and Advanced Processes through Silane Surface Treatment of Fe Nanopowder

For developing subminiature and highly integrated multilayer inductors, soft magnetic powder was used; however, its ferrite magnetic component is characterized by high resistivity and reduced direct current saturation, leading to the deterioration of the inductor under high currents. Therefore, herein, to improve the electromagnetic properties of thin-film inductors, Fe nanopowder was used to increase the volume fraction of magnetic sheets. Surface treatment was performed by using silane coupling agents, which improved the bonding strength and dispersibility of the Fe nanopowder with a heterogeneous epoxy binder. For uniform surface treatment on the nanopowder, the silane-treated powder was aged for 24 h, at a temperature of 3 °C. The surface-treated Fe nanopowder was used with a mixing ratio of the soft magnetic powder (coarse:fine:nano) of 7:2.5:0.5 wt.%; this was successful in producing a flexible and highly densified magnetic sheet. As a result, the volume fraction of the magnetic sheet for thin-film inductors to which a low-temperature aging-treated nanopowder was applied was significantly improved.