Inductance Calculation Research Articles

Significant contributions of the Higgs mode and impurity-scattering self-energy corrections to the low-frequency complex conductivity in dc-biased superconducting devices

We investigate the complex conductivity of superconductors under a direct-current (dc) bias based on the well-established Keldysh-Eilenberger formalism of nonequilibrium superconductivity. This robust framework allows us to account for the Higgs mode and impurity-scattering self-energy corrections, which are now known to significantly impact the complex conductivity under a bias dc, especially near the resonance frequency of the Higgs mode. The purpose of this paper is to explore the effects of these contributions on the low-frequency complex conductivity relevant to superconducting device technologies. We begin by nonperturbatively calculating the equilibrium Green’s functions under a bias dc, followed by an analysis of the time-dependent perturbative components. This approach enables us to derive the complex conductivity formula for superconductors ranging from clean to dirty limits, applicable to any bias dc strength. We validate our theoretical approach by reproducing known results and experimentally observed features, such as the characteristic peak in σ1 and the dip in σ2 attributed to the Higgs mode. Our calculations reveal that the Higgs mode and impurity-scattering self-energy corrections significantly affect the complex conductivity even at low frequencies (ℏω≪Δ), relevant to superconducting device technologies. Specifically, we find that the real part of the low-frequency complex conductivity, σ1, exhibits a bias-dependent reduction up to ℏω∼0.1, a much higher frequency than previously considered. This finding allows for the suppression of dissipation in devices by tuning the bias dc. Additionally, through the calculation of the imaginary part of the complex conductivity, σ2, we evaluate the bias-dependent kinetic inductance for superconductors ranging from clean to dirty limits. The bias dependence becomes stronger as the mean free path decreases. Our dirty-limit results coincide with previous studies based on the oscillating superfluid density (the so-called slow experiment) scenario. This widely used scenario can be understood as a phenomenological implementation of the Higgs mode into the kinetic inductance calculation, now justified by our calculation based on the robust theory of nonequilibrium superconductivity, which microscopically treats the Higgs-mode contribution. These results highlight the importance of considering the Higgs mode and impurity-scattering self-energy corrections in the design and optimization of superconducting devices under a bias dc. Published by the American Physical Society 2024

Mutual Inductance Calculation of Rectangular Coils at Arbitrary Position With Bilateral Finite Magnetic Shields in Wireless Power Transfer Systems

Mutual Inductance Calculation of Rectangular Coils at Arbitrary Position With Bilateral Finite Magnetic Shields in Wireless Power Transfer Systems

Inductive Calculation of Superconformal Indices Based on Giant Graviton Expansion

Abstract We investigate a simple-sum giant graviton expansion of the superconformal indices of ${\cal N}=2$ superconformal field theories realized on D3-branes probing 7-brane backgrounds with constant axio-dilation field. The expansion is of self-dual type, and imposes strong constraints on the indices. By using the constraints we determine the first few terms in the superconformal indices for arbitrary rank $N$.

Inductance Calculation and Analysis of Axial-Flux Slotless Surface-Mounted Permanent Magnet Machine With Equidirectional Toroidal Winding

Inductance Calculation and Analysis of Axial-Flux Slotless Surface-Mounted Permanent Magnet Machine With Equidirectional Toroidal Winding

An approach of dynamic wireless charging structure for an electric vehicle based on mutual inductance calculation

An approach of dynamic wireless charging structure for an electric vehicle based on mutual inductance calculation

AC loss calculation of no-electrical-insulation HTS magnets using a field-circuit coupling method

Abstract No-electrical-insulation (NEI) magnets are gradually exhibiting significant appeal due to their robust thermal stability and elevated mechanical strength. However, when exposed to AC conditions, these magnets will suffer more significant AC losses in dynamic electromagnetic devices, such as motors and maglev systems. Presently, the numerical methods for predicting the electromagnetic and loss behavior of large-scale NEI magnets entail high computation costs due to the substantial degrees of freedom or complicated modeling strategies. Thus, we propose a fully finite element method, referred to as the field-circuit coupling method, to efficiently assess the overall behavior of NEI magnets while preserving adequate accuracy. This method couples the T-A formula and the single-turn equivalent circuit through a global voltage, to avoid the costly and complicated inductance calculations, and to simultaneously consider the induced current. By further integrating the homogenization method, the calculation speed can be increased up to ten times. Additionally, we study the critical current, and the electromagnetic and loss behavior of the NEI magnets based on the proposed model. We identify some measurement methods that offer more precise estimations of the critical current and the turn-to-turn contact resistance of NEI magnets. Meanwhile, the results indicate the severe impact of high AC fields on the losses, and emphasize the importance of a reliable shielding structure for operational safety. Finally, the influence of turn-to-turn contact resistivity on the loss behavior is also investigated, which can provide valuable insights for the design of NEI magnets in dynamic electromagnetic devices.

Analytical Calculation of Mutual Inductance of D-Shaped Coils Applied to High-Temperature Superconducting Magnet

Analytical Calculation of Mutual Inductance of D-Shaped Coils Applied to High-Temperature Superconducting Magnet

Increasing efficiency of induction motor

In this work was analyzed induction motor, its advantages and disadvantages, and methods of modify it in way increasing its reliability and power coefficient. Power coefficient is the parameter which shows how much energy is used for yield and which just converting into heat. For analysis used calculation of induction motor which commonly used for developing serial asynchronous motor. Based on that calculation has modulated physical process which conducting in active parts of motor. For calculation of induction in armature and magnetic flux passes in it was used numerical mathematical model. This type of electric motors is common used so increase its efficiency and power characteristics is the one of way to reduce energy consuming. The developed way of modernization of induction motors, and analyzed reliability of it.

A Novel Inductive Gradient Calculation Method for Electromagnetic Rail Launcher and Its Optimization

A Novel Inductive Gradient Calculation Method for Electromagnetic Rail Launcher and Its Optimization

Completely Analytical Calculation of Inductance for Circular Coils With Bilateral Finite Magnetic Cores at Arbitrary Position in WPT Systems

Completely Analytical Calculation of Inductance for Circular Coils With Bilateral Finite Magnetic Cores at Arbitrary Position in WPT Systems

Analytical method of mutual inductance for T-R rectangular coils perpendicular to the planar medium

Some studies indicate that for specific defect detection in eddy current testing (ECT), the transmitter-receiver (T-R) probe models with tangential rectangular transmitter coil exhibit effective detection performance. In this context, mutual inductance being a crucial parameter. The calculation of mutual inductance for vertically oriented T-R coils is more intricate compared to that of parallel T-R coils, which is currently predominantly focused on circular mutual inductance analysis. This paper presents a closed-form formula for the mutual inductance of rectangular T-R coils oriented vertically to the conductor based on the method of the second-order vector potential approach. In this model, a form function concerning the coil's position and shape is defined, allowing convenient extension to T-R coils of arbitrary shapes and positions. Simultaneously, the validity of the theory is tested against experimental measurements on different positions and frequencies of coil systems above an aluminum plate. The results indicate good agreement between theoretical and experimental results within the 100 Hz to 100 kHz range. Consequently, this model can offer guidance for the calculation of mutual inductance for vertically oriented rectangular T-R coils in ECT.

The Influence of the Design of Antenna and Chip Coupling Circuits on the Performance of Textronic RFID UHF Transponders

The objectives of this study were to design, investigate, and compare different designs of coupling circuits for textronic RFID transponders, particularly focusing on magnetic coupling between an antenna and a chip. The configuration of the inductively coupled antenna module and the microelectronic module housing the chip can be varied in several ways. This article explores various geometries of coupling circuits and assesses the effects of altering their dimensions on mutual inductance, chip voltage, and the transponder’s read range. The investigation comprised an analytical description of inductive coupling, calculations of mutual inductance and chip voltage based on simulation models of transponders, and laboratory measurements of the read range for selected configurations. The results obtained from this study demonstrate that various designs of textile transponders are capable of achieving satisfactory read ranges, with some configurations extending beyond 10 m. This significant range provides clothing designers with the flexibility to select transponder designs that best meet their specific aesthetic and functional requirements.

Calculation of mutual inductance between arbitrarily positioned planar spiral coils for wireless power applications

Mutual inductance is one of the main parameters required to determine the power link’s performance (output voltage, efficiency) in wireless power transfer. The coils are often misaligned angularly in these applications, which affects the mutual inductance and thus the performance. Hence, an accurate calculation of mutual inductance is necessary to decide the working region of the coil. This paper presents an analytical calculation of mutual inductance between two planar spiral coils under angular misalignment conditions. By solving the Neumann integral formula, mutual inductance is derived for constant current-carrying coils, and the final mutual inductance value is calculated numerically. The influence of angular misalignment of the coil, which can be due to nutation and spin angles, on mutual inductance is studied in detail. The mutual inductance of the spiral coil is calculated for different misalignment cases. The accuracy of the calculation results is verified by comparing it with conventional formulas (mainly the Liu, the Babic formula, and the Poletkin formula) and by simulation using the finite element method. The proposed method is a more generalized and simpler one that can be used to calculate the mutual inductance of any size of coils, either spiral or circular, with any lateral and angular misalignments. Finally, a couple of spiral coils are fabricated to validate it experimentally. The comparison of the simulation and experiment results with the calculation result shows its accuracy. Thus, the proposed method can be applied to compute mutual inductance in any angularly misaligned coupling coils for the optimization of the wireless power transfer and their design.

Analysis on Transmission Characteristics of Dynamic Magnetic Coupling Mechanism of Racetrack Coil with Deflection Angles

In dynamic magnetically coupled contactless power transmission, the fluctuation of mutual inductance is caused by the relative motion between transmission and receiving coils, which affects the stability of power transmission. In order to reduce the fluctuation characteristics of power transmission, the mutual inductance calculation model of transmission mechanism including a racetrack coil with deflection angle is established by using Neumann formula, and the influence of different deflection angle and layout on mutual inductance fluctuation characteristics is analyse and compare. Then the power transmission system with LCC-S compensation for the transmission mechanism is established. The transmission characteristics of the racetrack coil with deflection angle are studied. The results show that reasonable design of the deflection angle can reduce the fluctuation of the mutual inductance and the power output in dynamic transmission. The fluctuation of power output can also be reduced by changing the distance between transmission coils and the length of straight side of receiving coils.

Calculation and regulation of mutual inductance of wireless charging coils with metal shielding materials based on multiple intelligent optimization algorithms

SummaryIn wireless charging systems for electric vehicles, fluctuations in coil mutual inductance can affect both system output power and efficiency. This paper introduces a coil mutual inductance model that accounts for metal shielding material. The formula for coil mutual inductance is derived using Maxwell's equations and boundary conditions. Additionally, the paper presents a tactic for adapting the mutual inductance with the aid of an intelligent optimization algorithm, which is utilized for steadying the mutual inductance of the transmission coil. Lastly, a model of the transmission coil is developed to authenticate the practicality of the mutual inductance equation and the adaptation scheme. Measurement and calculation results indicate that the difference between the calculated value of the mutual inductance formula and the actual mutual inductance value of the coil, following deflection and offset, is below 5%. Moreover, the algorithm, along with the employed adaptation strategy, consistently demonstrates effectiveness in maintaining the mutual inductance value within a predefined range. The temporal efficiency of the algorithm, as measured by the time taken to determine this coordinate position, is consistently under 1 s. This ensures that the algorithm exhibits a rapid response time, a crucial attribute in ensuring its practical utility.

D-Q Axis Inductance Analytical Calculation for Fractional-Slot Distributed Winding IPM Motor Based on Big-Small Pole Space Method

The d-q axis inductance is the crucial parameter for the interior permanent magnet (IPM) motor. In order to facilitate the design, analysis, and optimization of IPM motors, it is of great significance to develop an accurate and simplified inductance analytical calculation method. Among the existing calculation methods, the magnetic equivalent circuit (MEC) has advantages in the inductance calculation of the IPM motor due to the simple modeling, the fine processing of the saturation region and the visualization of the magnetic field distribution. However, the traditional MEC method is only applicable to the IPM motor with integer-slot distributed winding (ISDW) or fractional-slot concentrated winding (FSCW), while lacking of in-depth research on fractional-slot distributed winding (FSDW). The magnetic circuit topology of FSDW IPM motors is not as single as that of FSCW/ISDW IPM motors. It leads to problems in the traditional MEC method when dividing the d/q axis flux path in FSDW motors. To solve this problem and expand the applications of MEC method, a big-small pole space (BSPS) method is proposed after fully considering the common characteristics of MMF distribution and reluctance distribution in FSDW motors, which fills the gap of MEC method applied to FSDW motors. The BSPS method divides the d-axis flux path according to the asymmetry of the d-axis magnetomotive force (MMF). Based on the divided flux paths, an improved nonlinear MEC model that considers the saturation of stator and rotor is established to calculate d- and q-axis inductances. The results of finite element analysis (FEA) verify the validity of the proposed MEC model with different geometry parameters. Experimental results of an 84-pole/360-slot FSDW I-type IPM wind generator further confirm the validity of the proposed MEC model

Calculation of inductances and induced currents in cryogenic by-pass line for SIS100 particle accelerator at FAIR

Calculation of inductances and induced currents in cryogenic by-pass line for SIS100 particle accelerator at FAIR

Calculation of Resistances and Inductances in Multi-Conductor Systems Including Solid and Litz Wires Using the 2-D Boundary Element Method

Calculation of Resistances and Inductances in Multi-Conductor Systems Including Solid and Litz Wires Using the 2-D Boundary Element Method

A Sensorless Heavy Load Starting Control Method For SRMs With Residual Inductance Calculation and Polynomial Fitting

A Sensorless Heavy Load Starting Control Method For SRMs With Residual Inductance Calculation and Polynomial Fitting

Two-Dimensional Frequency-Dependent Resistance and Inductance Calculation Method for Magnetic Components With Round Conductors

Two-Dimensional Frequency-Dependent Resistance and Inductance Calculation Method for Magnetic Components With Round Conductors