Loss Of Induction Research Articles

High-Frequency High-Magnetic Flux Variation Foil Winding AC Inductor Design with the Vertical Penetrating Magnetic Field Elimination

In traditional inductor design with planar windings, the magnetic field distribution may not be well-organized, leading to significant winding loss, particularly at high switching frequencies. This study explores the relationship between current distribution and magnetic field distribution in the winding region. Unlike conventional magnetic flux distribution, which directs a large portion of the magnetic field vertically through the windings in the winding region, this work introduces a structure that maintains most of the magnetic flux parallel to the foil windings through the application of quasi-distributed air gaps. This paper presents a design methodology for a high-frequency foil winding inductor with high flux variation. Building on this concept, a high-power density, low loss inductor with foil windings is designed based on the four-switch buck-boost (FSBB) converter. Experimental results demonstrate that the proposed inductor design significantly reduces winding loss in inductors with planar windings.

Core losses analysis of the LCL filter inductor for SiC-based inverter

The ability of SiC devices to switch at high speed allows increasing significantly the power density in both converters and passive components, reducing their required size. To mitigate harmonic injection form inverters into the grid, in order to comply with power quality standards, an accurate filter design is required. Given its excellent performance, an LCL filter is the configuration most suitable in grid-connected power converters. Several parameters must be considered when designing an effective LCL filter, and the inverter-side inductor assumes a special importance because of its relevance to suppress high frequency harmonic content at the inverter side. One of the most relevant issues to be considered in the process of designing the LCL filter is the evaluation of core losses in the inverter-side inductor, which will determine the final temperature of the inductor. This paper analyses the core losses of the inverter-side inductor of an LCL filter. The proposed method is based on the computation of the current harmonics generated by the inverter and on Steinmetz’s empirical equation. As a result, core losses calculated taking into account several carrier and sideband harmonics show good agreement with the experimental values. When current harmonics are estimated by simulation, as it is done in the proposed design procedure, results are less accurate, but precise enough for a design procedure.

Technical Reviews of Power Loss Optimization in High-Frequency PSiPs—In Relation to Power Switches and Power Inductors

Power losses of switches and inductors are consistent challenges that hinder the development of high-frequency power supply in package (PSiP). This paper investigates the roadmap for power loss optimizations of switches and inductors in high-frequency PSiPs. Firstly, a size and parallel quantity design method to reduce power loss in an integrated Si LDMOSFET is provided with comprehensive consideration of switching frequency and power levels. Secondly, quality factors of different air-core inductors are analyzed with consideration of geometric parameters and skin effect, which provides the winding structure optimization to reduce power losses. The power losses of the integrated Si LDMOSFET and air-core inductors are both reduced to less than 10% of the output power at 1~100 MHz switching frequency and 0.1~10 W power level. Finally, based on the above optimizations, power losses of switches and inductors are calculated with switching frequency and power level. Combining the calculated results, this paper predicts the efficiency boundaries of PSiPs. Upon efficiency normalization with consideration of input and output voltage levels, all the predictions are consistent with the published literature. The efficiency predication error is 1~15% at 1~100 MHz switching frequency and 0.1~10 W power level. The above power loss optimizations improve the efficiency, which provides potential roadmaps for achieving high-frequency PSiPs.

Modeling and Control of a DC-DC Buck–Boost Converter with Non-Linear Power Inductor Operating in Saturation Region Considering Electrical Losses

The present work proposes a nonlinear model of a buck–boost DC-DC power converter considering the nonlinear magnetic characteristics of the power inductor and electrical losses of the system. The Euler–Lagrange formalism is used for formulating the proposed model. Previous research works have reported mathematical models to describe power inductor dynamics. However, a gap in the literature remains regarding modeling this kind of element when it operates within power converters. Also, a linear-based controller scheme is proposed to regulate a non-ideal buck–boost DC-DC power converter. A methodology for tuning the proposed controller is presented, which considers the nonlinear model structure of the power converter, the linearization procedure based on an identification process, and a frequency domain analysis based on the approximated linear model. Finally, the tuned control scheme is tested on the nonlinear model of the power converter under several operational conditions showing excellent performance by effectively regulating the output voltage. The results are compared with those derived from alternative control strategies, and a better performance is generally obtained.

Optimum number of cascade cells for multilevel inverter considering redundancy strategies based on cost and reliability optimization

AbstractThis paper proposes an economical reliability‐oriented solution to determine the optimal number of cascade cells and redundancies for STATCOM using a Non‐Dominated Sorting Genetic (NSGA‐II) algorithm based on different redundancy configuration schemes. A multi‐objective optimization framework is presented, to minimize the total cost and maximize its reliability index by considering power quality issues. In the presented model, a new cost modelling is introduced considering the cost of inductor loss. The multilevel cascade topology with staircase modulation strategy is also taken into account. The effectiveness of the proposed optimization framework is validated by the NSGA‐II algorithm compared to the results of goal attainment and goal programming as decomposition single‐objective optimization methods. The results verify that the proposed multi‐objective optimization framework could be useful in the optimal selection of high‐voltage STATCOM levels in the presence of redundancies while ensuring the required level of reliability at the minimum cost. Also, the presented NSGA‐II optimization algorithm is applicable to maintain both objective functions at an acceptable value.

Magnetic Properties of the Soft Magnetic Composites Prepared Using Mixtures of Carbonyl Iron, FeSiCr, and FeSiAl Alloy Powders.

The effect of carbonyl iron powder, FeSiCr alloy powder, and annealed FeSiAl alloy powder, both individually and in binary combinations, on the density, microstructure, and magnetic properties (including permeability and power loss) of inductors manufactured by molding compaction was investigated in this study. The investigation demonstrates that hysteresis loss dominates power loss in the tested frequency range. Due to higher compacted density and reduced coercivity, adding 50% carbonyl iron powder to annealed powder resulted in the lowest hysteresis loss, allowing for domain wall movement. On the other hand, adding 50% FeSiCr alloy powder to annealed powder resulted in higher hysteresis loss due to impurity components hindering domain wall motion. Due to extreme plastic deformation, the carbonyl iron powder and FeSiCr alloy powder combinations displayed the most significant hysteresis loss. Eddy current loss followed the same trends as hysteresis loss in the mixtures. This study provides important insights for refining the soft magnetic composite design to obtain higher magnetic performance, while minimizing power loss.

AC Copper Loss Reduction in Planar Inductors With Magnetic Building Blocks-Based Gapless Parallel Symmetrical Magnetoresistance Structure

Fringing and proximity effects are the main reasons for serious ac copper loss in high-frequency planar inductors. In this article, a novel air-gapless core structure based on magnetic building blocks with magnetoresistance parallel and symmetrically distributed relative to the windings is proposed, in which two magnetic building blocks parallel to the PCB windings are made of metal soft magnetic material with low relative permeability and three magnetic building blocks perpendicular to windings are made of ferrite with high relative permeability. Equivalent magnetic circuit models and theoretical analysis for the proposed core structure reveal that even if the interleaved winding structure fails in the inductor, a better distribution of magnetomotive force can be obtained by optimizing the distribution of magnetoresistance. Compared with the conventional inductors using stand airgaps, both the fringing and proximity effects can be weakened by the designed parallel symmetrical magnetoresistance core structure, which has been verified in three-dimensional finite element analysis (FEA)-based simulations. The FEA calculated results show that the proposed optimized core structure can achieve a 46% reduction in ac resistance, and this advantage will extend with increasing frequency over a certain frequency range. The experimental validation includes converter efficiency test and inductor loss test on a high-frequency critical conduction mode Boost converter has been carried out, the maximum efficiency improvement was 1.4% and the inductor loss reduction is also verified.

Analytical Modeling of High-Frequency Winding Loss in Round-Wire Toroidal Inductors

Toroidal inductors are used in many industrial applications in which they are key components regarding cost and volume. In the inductor design process, it is paramount to accurately estimate its high-frequency winding loss. Finite element analysis (FEA) software and analytical models can be used for this purpose. However, the former employs too much time and the latter lacks accuracy when applied to toroidal windings, leading to an overestimation that can exceed 200%. As a consequence, designers would benefit from a reliable method to calculate high-frequency loss in toroidal windings. This paper proposes an analytical model that considers the 2-D characteristic of the magnetic field and the geometrical particularities of toroidal windings. Furthermore, it provides an easy-to-use method, which avoids the unaffordable computational cost of FEA software. Simulations and experimental measurements are carried out for six toroidal power inductors, from 10 Hz up to 200 kHz. Three different well-known state-of-the-art analytical models are used for comparison purposes. The results obtained with the proposed model are in good agreement with those from FEA and the experiments. The proposed model shows a maximum deviation below 20%, while the overestimation of the existing analytical methods reaches values from 93% to 226%.

A comprehensive study of grid impedance and its reliability effects on variable frequency drive

<p class="Text">Grid impedance is one of the most important parameters for the satisfactory operation of variable frequency drive (VFD) and their interaction with other utilities connected to the same grid. In this research investigation a new approach to analytical evaluation and verification of grid impedance, and short circuit current is discussed. VFD under identical operating and loading conditions is connected to different grid capacities and configurations, being considered in this investigation. Grid impedance variation in terms of measured or estimated values, due to different grid connectivity affects the commutation of uncontrolled front-end rectifiers. This impacts the nonlinearity of input current wave shape, causing a significant change in current harmonics (THDi) and ripple current of DC link. This paper comprehensively investigates the reduction of DC capacitor lifetime and losses of DC inductor, and diode with various grid capacity and configurations under standard load conditions. High-frequency harmonics impact (2-9 kHz) on DC inductor losses is also analyzed. A VFD of 250 kW is considered for entire practical measurement including distortion effects and MATLAB simulation. This research may give a good insight into the sizing of VFD front-end devices. The reliability impact of VFD is also one of the important outcomes of this research.</p>

Analytical modelling of high‐frequency losses in toroidal inductors

AbstractToroidal inductors are widely used in power electronic systems. With the increasing switching frequency of power devices, the AC losses of high‐frequency inductor windings have become an issue that cannot be ignored in design. A method with low computational time cost and high accuracy is urgently needed by designers. This paper proposes a modified analytical method for winding loss calculation of toroidal inductors based on the one‐dimensional Dowell method and the two‐dimensional Ferreira method, and proposes a compensated analytical model considering the proximity effect of inter‐turn conductors of toroidal windings. The analytical method calculates the non‐linear porosity of toroidal windings, and can accurately solve the AC losses of toroidal inductors with arbitrary porosity winding encapsulation. The analytical results are in good agreement with the finite element method (FEM) and experimental data. The experimental measurement data verifies the validity of the proposed model within 1‐MHz frequency, the calculation error of the modified analytical method is less than 25%, and the calculation error of the compensated analytical model is reduced to 10%.

実験値とデータシート値と近似式から構築した電力変換器の損失モデルの実機検証

This paper proposes a losses-analysis model of a DC-output converter based on the approximated equations from measurements and a datasheet. Target verification circuit consists of a DC-voltage source, a smooth capacitor, two half bridge legs, and a load inductor connected to the midpoints of the half bridge legs, which controls the continuous average DC current of the load inductor. A use of self-measured data, compared with the use of datasheet values, enables expanding the ranges of the considerable target parameters. Hence, lesser order approximated equations can deal with more target parameters with less calculation period than that in a conventional time domain simulation. In this study, calculation flow of losses from losses of power devices and an inductor to circuit losses was developed. Subsequently, a semiconductor losses model and inductor losses model were developed via the linear least square method. Finally, a 400V experimental system was developed to verify the accuracy of the circuit losses at 16 specified operating conditions by varying three verification parameters, switching frequency, gate resistance, and inductance. The result shows that the losses calculated using the proposed model has good accuracy with an error of 1.9% to 10.6% to the measured result.

Determination of the Optimal Number of Phases of a Multiphase Bidirectional Chopper Considering AC Loss in Inductor

This study focuses on the loss of inductors in a multiphase bidirectional chopper, which is a DC-DC conversion system. The current at the inductors in a multiphase bidirectional chopper consists of a DC current equivalent to the load current and an AC current called ripple current. The discussion regarding the effect of the increased number of phases should include the loss due to the ripple current, which is caused by semiconductor switching. Therefore, this study clarifies the loss due to the ripple current from an experiment with an increase in temperature. From the extraction of AC loss from the total loss, it is demonstrated that the loss due to the ripple current is equivalent to the no-load loss in the multiphase bidirectional chopper. When the number of phases increases, the load loss decreases whereas the no-load loss increases. This relationship indicates that an optimal number of phases exist according to the load current. This study deduces an analytical solution for the optimal number of phases and applies the methodology for determining the optimal number of phases to an actual onboard bidirectional chopper for an onboard energy storage system and traction system as an example. The optimal number of phases differs depending on the application.

Design of a Packaged Multi-radius Multi-path Solenoidal Inductor for Redistribution Layers

This paper proposes a three-dimensional solenoidal inductor using a “multi-radius multi-path” (MRMP) structure that targets integrated voltage regulators (IVRs). Multi-radius (MR) refers to the inclusion of additional turns inside the solenoid, and multi-path (MP) describes the division of a single metal into two paths to reduce non-uniformity in currents due to differences in length. Using an MRMP structure, we propose two new inductor designs for fan-out wafer-level packaging. A two-layer MRMP approach that implements the multi-path in an additional layer, and a one-layer MRMP configuration avoids the need for an additional layer by incorporating the multi-path in an inner turn. We compare inductance and quality performance according to the frequency of the two designs. When the MR technique is applied, the inductance increases due to the increase in the length of the inductor, but resistance also increases. As the frequency increases, alternating current (AC) resistance becomes dominant. The MP increases the quality factor by alleviating skin and proximity effects, which are the main causes of increased AC resistance. Analytical modeling is carried to rapidly estimate and optimize direct current inductance using partial inductance. To verify the improvement in efficiency due to the proposed inductor structure, we propose a prototype IVR that includes inductor loss and investigate the efficiency with circuit simulations using an IVR design with a conversion ratio of 3.6 V:1.8 V operating at 10 MHz. By using the two-layer MRMP inductor, the prototype IVR efficiency increases from 72.6% to 82.1%. A one-layer MRMP inductor, an IVR design with conversion ratio of 1.8 V:1.0 V and an operating frequency of 40 MHz, increases the maximum efficiency from 56.6% to 75.1%.

Accurate Efficiency and Power Densities Optimization of Output Inductor of Buck Derived Converters

In this article, inductor loss models are developed based on the experimental characterization of off-the-shelf components. The modelling steps and techniques are described and validated. It is shown that the model exhibits fairly good accuracy over a large range of ripple current frequency and magnitude. Then, these models are used, as an illustration, in order to present the possible optimization process of the tradeoff between switching frequency-current ripple magnitude and output inductors value in the case of a Buck-derived converter. This optimization has shown that a large current ripple may lead to minimized losses in some cases. The developed modelling technique aims to represent Joules and iron losses, as well as DC and AC losses of inductors. It is not based on physical behaviour description but on mathematical equations based on a set of experimental characterizations. The modelling technique is not suitable for designing the component itself but is useful for selecting the best component value in the manufacturer’s series of components. Since it remains difficult with the manufacturer datasheet to estimate AC losses accurately with respect to frequency and ripple current magnitude, a specific characterization is carried out to complement the available data.

A Second Order 1.8–1.9 GHz Tunable Active Band-Pass Filter with Improved Noise Performances

In this paper, a novel active tunable band-pass filter with improved noise performances is presented. This filter is based on a negative resistance circuit (or active capacitance), where the gain obtained with a transistor is used to compensate for inductor losses. Moreover, the capacitance of the resonator is obtained through a voltage-controlled reverse-biased varactor, which allows for frequency tuning. Despite the active component, the proposed filter also has good noise performance. Measurements show a tunability range from 1.816 GHz to 1.886 GHz, with a bandwidth of 38 MHz. The insertion loss maximum value is 0.4 dB, while the noise figure value has a minimum value of 2.5 dB at the center frequency within the tunability range.

Modeling Push–Pull Converter for Efficiency Improvement

In this paper, we model and analyze the power losses of push–pull converters. The proposed model considers conduction and dynamic power losses, as well as transformer and inductor losses. Transformer and inductor models include skin and proximity effects, as well as power losses in the core. Moreover, the model includes the diode recovery time losses. We derived the equations for both continuous and discontinuous current operating modes. All model parameters can be obtained either from the datasheets of the used components or by simple measurement techniques. The model is verified experimentally by measuring the efficiency of the 500 W push–pull converter prototype. Simulations and experimental validation are conducted using the assumption that the converter is used in a permanent magnet (PM) wind turbine generator.

Abrupt changes detection using wavelet-based denoising analysis

Switching power supply is an essential power supply method that exists in the development of the electronic information industry. Drive power supply has various quality problems, primarily due to the loss of power inductors; for power inductor capacity testing, making a feasibility assessment is of great significance. In this study, we present a wavelet-based approach for detecting sudden changes in the power inductor current curve. To reliably identify rapid changes in the saturation of the inductor current after energization, the discrete wavelet transform is utilized to analyze the signal within a specified subset of all scaling and translation values, displaying different local signal characteristics.

Investigating Substrate Loss in MEMS Acoustic Resonators and On-Chip Inductors.

This work studies the influence of substrate loss on the performance of acoustic resonators and on-chip inductors and investigates the effective substrate resistivity of seven commonly used substrates in silicon-based devices. The substrates include X-cut lithium niobate (LiNbO3) film with two different thicknesses (400 nm and 1.6 [Formula: see text]) on high-resistivity Si (HR-Si) and amorphous Si wafers, SiO2 film with two different thicknesses on HR-Si, and bare HR-Si. The effective resistivities of these substrates are extracted using coplanar waveguides (CPWs) over a frequency range from 1 to 40 GHz. Using the effective resistivity approach, the efficiency of two substrate loss reduction techniques-Si wafer removal and amorphous Si-in reducing substrate loss is quantified. Comparison of the extracted substrate resistivities of the suspended and un-suspended dielectric-on-Si structures and comparison of LiNbO3 on HR-Si and amorphous Si are carried out. Substrate loss reduction techniques are more advantageous for a thinner dielectric film and at a lower frequency range due to the higher filling factor of the electric field in the Si wafer. Finally, by comparison of the effective substrate resistivity of SiO2 film on an HR-Si with bare HR-Si, thick plasma-enhanced chemical vapor deposition (PECVD) SiO2 film is found to be a good insulation layer to reduce substrate loss.

Balance Techniques and PCB Winding Magnetics for Common-Mode EMI Noise Reduction in Three-Phase AC–DC Converters

In this article, balance technique is applied into two-channel interleaved three-phase ac–dc converters with critical conduction mode based soft switching modulation. By adding additional inductors and coupling them with the original ones, the realization of the balance becomes possible with proper design; thus reducing the common-mode (CM) EMI noise. The balance condition is derived, and the impact of balance technique on the circuit operation especially on the switching frequency variation is quantified in order to provide the design guideline. Based on the application of balance technique, instead of the commonly used litz-wire-based inductors, PCB winding coupled inductors are adopted and designed to effectively achieve the reduction of CM EMI noise. The design methodology and process are presented, and the design tradeoff is made between the inductor loss and the inductor footprint. Finally, the effect of CM EMI noise reduction and the system efficiency with balance techniques and PCB winding magnetics are tested on a 25-kW silicon-carbide-based soft-switching three-phase ac–dc converter prototype.

Inductor Design for Nonisolated Critical Soft Switching Converters Using Solid and Litz PCB and Wire Windings Leveraging Neural Network Model

High frequency and high efficiency inductor design method is proposed for the application of critical soft switching with large current ripple to improve the power density and efficiency of electrified energy conversion systems. Firstly for the theoretical design section, the core/coil size, number of turns, airgap, inductance are optimized to minimize the inductor losses. Secondly for the structural design section of coil, a 3D routing method of litz PCB winding is developed to reduce the AC copper losses. The strand number, trace width, thickness and layout of litz PCB are analyzed in detail. Different types of coil, including solid/litz types of PCB/wire windings, are compared and analyzed based on the high frequency copper loss reduction and space utilization. For the structural design section of core, E and I cores are optimized to reduce the volume and core losses. Specifically, E-E, E-I, I-I and E-Air types of core structures are designed and compared considering the core loss, volume reduction and airgap limitation for the stack of turns. Ten derived prototypes are built to benchmark with the commercial inductors. Power losses, temperature rise and cost are reduced by a factor of 10, 2.5 and 3 with the proposed core and coil structures.