Fast Inductance Research Articles

A Deep Learning Approach to Improve the Control of Dynamic Wireless Power Transfer Systems

In this paper, an innovative approach for the fast estimation of the mutual inductance between transmitting and receiving coils for Dynamic Wireless Power Transfer Systems (DWPTSs) is implemented. To this end, a Convolutional Neural Network (CNN) is used; an image representing the geometry of two coils that are partially misaligned is the input of the CNN, while the output is the corresponding inductance value. Finite Element Analyses are used for the computation of the inductance values needed for CNN training. This way, thanks to a fast and accurate inductance estimated by the CNN, it is possible to properly manage the power converter devoted to charge the battery, avoiding the wind up of its controller when it attempts to transfer power in poor coupling conditions.

Rotating-Coordinate-Based Mutual Inductance Estimation for Drone In-Flight Wireless Charging Systems

This article proposes a fast and real-time mutual inductance estimation method for drone in-flight wireless charging systems against the continuous varying of relative position between coupling coils. In previous studies, many efforts have been made to achieve accurate mutual inductance estimation when fixed misalignment occurs in coupling coils. However, the critical challenge for in-flight wireless charging systems is to track variations of mutual inductance caused by continuously changed misalignments between coupling coils, which is rarely explored in previous studies. Accordingly, this article proposes a rotating-coordinate-based mutual inductance estimation method to track the variation of the mutual inductance timely. By applying the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> dynamic model, the proposed estimation method is effectively enhanced in terms of rapidity and implemented simply as well as eliminating wireless communication links. With the salient features of accuracy, rapidity, and real time, it can be an ideal solution against the continuous disturbance of mutual inductance, especially for drone in-flight wireless charging systems. In this article, both simulated and experimental results are given to verify the validity of the proposed rotating-coordinate-based estimation method, wherein the relative error of the mutual inductance estimation is within 1%, and the estimation rapidity is less than 4 ms.

Inductive Power Transfer System With Maximum Efficiency Tracking Control and Real-Time Mutual Inductance Estimation

To design simple and efficient inductive power transfer (IPT) systems, a minimum number of conversion stages and an effective maximum efficiency tracking (MET) are the primary design criteria. The MET control uses a fast mutual inductance estimation (MIE) algorithm to achieve fast tracking of the maximum efficiency point, especially when the variation of the gap distance and misalignment of the magnetic coupler are significant. The feedback control of the MET-MIE IPT system should be designed without a wireless communication channel to improve stability and robustness. In this article, a novel MET-MIE control strategy is proposed for achieving simplicity and high efficiency in IPT systems. Verifications are provided by simulations and experiments. It is shown that maximum efficiency can be tracked with less than 4&#x0025; error in MIE under significant variation of the gap distance and misalignment of the magnetic coupler.

AC loss modelling and experiment of two types of low-inductance solenoidal coils

Low-inductance solenoidal coils, which usually refer to the nonintersecting type and the braid type, have already been employed to build superconducting fault current limiters because of their fast recovery and low inductance characteristics. However, despite their usage there is still no systematical simulation work concerning the AC loss characteristics of the coils built with 2G high temperature superconducting tapes perhaps because of their complicated structure. In this paper, a new method is proposed to simulate both types of coils with 2D axisymmetric models solved by H formulation. Following the simulation work, AC losses of both types of low inductance solenoidal coils are compared numerically and experimentally, which verify that the model works well in simulating non-inductive coils. Finally, simulation works show that pitch has significant impact to AC loss of both types of coils and the inter-layer separation has different impact to the AC loss of braid type of coil in case of different applied currents. The model provides an effective tool for the design optimisation of SFCLs built with non-inductive solenoidal coils.

Multifunction Approach and Specialized Numerical Integration Algorithms for Fast Inductance Evaluations in Nonorthogonal PEEC Systems

This paper focuses on two special aspects regarding fast partial inductance computations in the nonorthogonal partial element equivalent circuit (PEEC) method. First, a multifunction PEEC algorithm is proposed, which is able to calculate partial inductances as efficient as possible for mixed environments with nonorthogonal as well as orthogonal cells. Second, a new numerical integration routine for the self-inductance terms of nonorthogonal cells is focused on by using averaged orthogonal subelements. It is presented that the slow convergence caused by the singularities is avoided and a fast evaluation of the self-terms is enabled consequently. The approach is verified by two examples where a good agreement is obtained when comparing the proposed results with analytical solutions as well as finite-element method reference results.

Modeling Inductances of Wiring for a TES Array Read by FDM

Large Transition Edge Sensor (TES) arrays, required for the SAFARI imaging spectrometer on a planned SPICA space telescope, will be read out by Frequency Division Multiplexing (FDM). All the pixels are connected with densely packed and equally long superconducting wires. Inductive coupling between wire pairs forms critical performance issues. Mutual inductance is one of the origins of electronic crosstalk among pixels. We find that available literature is not complete in providing suitable calculation methods for the required modelling. In this paper, we describe a relatively fast inductance calculation method for long, arbitrary wires, which can be useful for analyzing crosstalk between pixels and can also be important for guiding wiring layout design. The mutual inductance between two wire loops is calculated using Neumann's formula by a double summation of analytical expressions implemented in Python. Self-inductance for a multi-segment wire can be calculated by the summation of self-inductance of each wire segment and the mutual inductance between all segments. Combining this method with other modelling techniques, we have simulated the inductances of an entire 160 pixel FDM test setup.

Inductance calculation of high-speed slotless permanent magnet machines

Purpose – The purpose of this paper is to give a simple, fast and universal inductance calculation approach of slotless-winding machines and comparison of inductances of toroidal, concentrated and helical-winding machines, since these winding types are widely used among low-power PM machines. Design/methodology/approach – Harmonic modeling approach is applied to model the magnetic field of the windings in order to calculate the synchronous inductances. The method is based on distinction between electromagnetic properties of different regions in the machine where each region is represented by its own governing equation describing the magnetic field. The governing equations are obtained from Maxwell’s equations by introducing vector potential in order to simplify the calculations. Findings – Results of the inductances of toroidal, concentrated and helical-winding slotless PM machines, which have the same torque and dimensions, obtained by the proposed analytical method are in good agreement with 3D FEM, where the relative difference is smaller than 15 percent. However, the calculation time of the analytical method is significantly less than in 3D FEM: seconds vs hours. Additionally, from the results it is concluded that the toroidal-winding machine has the highest inductance and DC resistance values among considered machines. Helical-winding machine has lowest inductance and DC resistance values. Inductance of concentrated-winding machine is between inductance of helical and toroidal windings; however, DC resistance of the concentrated windings is comparable with resistance toroidal windings. Originality/value – In this paper the inductance calculation based on harmonic modeling approach is extended for toroidal and helical-winding machines which makes the method applicable for most of the slotless machine types.

Fast and accurate inductance and coupling calculation for a multi-layer Nb process

Currently, fabrication processes for superconductive integrated circuits are moving to multiple wiring and shielding layers, some of which are placed below the main ground plane (GP) and device layers. The Advanced Industrial Science and Technology advanced process (ADP2) was the first such multi-layer Nb process with planarized passive transmission line and GP layers below the junction layer, and is at the time of writing still the most developed. This process allows complex circuit designs, and accurate inductance extraction helps to push the boundaries of the layouts possible. We show that the position of ground connections between ground layers influences the inductance of structures for which these GPs act as return path, and that this needs to be accounted for in modelling. However, due to the number of wiring layers and GPs, full layout modelling of large cells causes long calculation times. In this paper we discuss methods with which to reduce model size, and calibrate InductEx calculations using these methods against measured results. We show that model reduction followed by calibration results in fast calculation times while good accuracy is maintained. We also show that InductEx correctly handles coupling between conductors in a multi-layer layout, and how to model layouts to gauge unwanted coupling between power lines and single flux quantum electronics.

A Fast Inductance Computation Devoted to the Modeling of Healthy, Eccentric, and Saturated Induction Motors

This work deals with a detailed method for the calculation of induction motor inductances based on the convolution theorem. The integral form leading to the inductance expressions is derived from the 2D modified winding function approach, which takes into account the space harmonics, slot skewing, and radial and axial air-gap eccentricities. As first applications, a model is presented that allows teeth saturation to be taken into account by the corresponding air-gap permeance variation. Next, the idea is adapted to the rotor eccentricity modeling. It is shown that appropriate arrangements make it possible to use the convolution theorem for fast calculation of the inductances. The proposed method proves to be competitive compared to the conventional techniques of integration and even those employing equivalent analytical expressions. To demonstrate the effectiveness of the new proposed methodology, simulation tests based on the multiple coupled circuit model, experimental spectra, as well as time processing verification on a personal computer, are provided.

Parallel computing applied to inductance calculation for flexible inductors

PurposeThe motivation for this research work is the need for an efficient software tool for inductance calculation of components in flexible electronics. A software package PROVOD has been developed and it has produced very accurate results but the applied numerical method can lead to a huge amount of calculations. The aim of this research is to apply the parallel computing to this specific computational technique and to investigate the impact of increasing the number of parallel executing threads.Design/methodology/approachThe largest possible amount of operations is put in parallel using the fact that the inductance between two segments is a sum of independent elements. OpenMP and Microsoft's Concurrency Runtime have been tested as parallel programming techniques.FindingsParallel computing with a different number of threads (up to 24) has been tested with OpenMP. A significant increase in computational speed (up to 21 times) has been obtained.Research limitations/implicationsThe research is limited by the available number of parallel processors.Practical implicationsAccurate and fast inductance calculation for flexible electronic components is possible to achieve. The impact of parallel processing is proven.Social implicationsThe proposed method of calculation acceleration of inductances can be helpful in the design and optimization of new flexible devices in electronics.Originality/valueParallel computing is applied to the design of flexible electronic components. It is shown that a large number of parallel processors can be efficiently used in this type of calculation. The obtained results are interesting for people involved in the design of flexible components, and generally, for researchers/engineers dealing with similar electromagnetic problems.

Analytic and Iterative Algorithms for Online Estimation of Coupling Inductance in Direct Power Control of Three-Phase Active Rectifiers

One of the best known control methods for three-phase active rectifiers is the so-called direct power control (DPC). The control algorithm of the DPC is primarily based on the regulation of instantaneous active and reactive power. Because the DPC method can operate without any grid voltage sensors, instantaneous power and grid phase voltages must be estimated. The value of the essential coupling inductor between the rectifier and its three-phase supply play an important role in these estimations. This value is theoretically known; however, the grid inductance, which is sometimes difficult to determine precisely, or the coupling inductor tolerance, among other factors, may lead to errors in the inductance value. These errors have a negative and considerable effect on the instantaneous power and grid voltage estimation. Therefore, they provoke an improper operation of the DPC algorithm and the rectifier itself. To avoid these drawbacks, two simple, fast and robust inductance online estimation algorithms (analytic and iterative) are proposed in this paper. The proper operation of both methods is shown by simulation and experimental results.

Novel efficient methods for inductance calculation of meander inductor

PurposePresent 3D electromagnetic simulators have high accuracy but they are time and memory expensive. Owing to a fast and simple expression for inductance is also necessary for initial inductor design. In this paper, new efficient methods for total inductance calculation of meander inductor, are given. By using an algorithm, it is possible to predict correctly all inductance variations introduced by varying geometry parameters such as number of turns, width of conductor or spacing between conductors.Design/methodology/approachThe starting point for the derivation of the recurrent formula is Greenhouse theory. Greenhouse decomposed inductor into its constituent segments. Meander inductor is divided into straight conductive segments. Then the total inductance of the meander inductor is a sum of self‐inductances of all segments and the negative and positive mutual inductances between all combinations of straight segments. The monomial equation for the total inductance of meander inductor has been obtained by fitting procedure. The fitting technique, using the method of least squares, finds the parameters of the monomial equation that minimize the sum of squares of the error between the accurate data and fitted equation. The paper presents new expression for inductance of meander inductor, in the monomial form, which is suitable for optimization via geometric programming. The computed inductances are compared with measured data from the literature.FindingsThe first, recurrent, expression has the advantage that it indicates to the designer how the relative contributions of self, positive, and negative mutual inductance are related to the geometrical parameters. The second expression presents the inductance of the meander inductor in the monomial form, so that the optimization of the inductor can be done by procedure of the geometric programming. Simplicity and relatively good accuracy are the advantages of this expression, but on the other hand the physical sense of the expression is being lost. Thus, the effects of various geometry parameters on inductance are analyzed using two expressions and the software tool INDCAL.Practical implicationsApplied flexible efficient methods for inductance calculation of meander inductor are able to significantly increase the speed of RF and sensor integrated circuit design.Originality/valueFor the first time a simple expression for fast inductance calculation for meander inductor in monomial form is presented. It is explained how such an expression is generated, which can be directly implemented in circuit simulators.

Compact form of expressions for inductance calculation of meander inductors

The quality of modeling and analyzing of RF IC with planar inductors extremely depends on accuracy of expression for inductance. In this paper efficient methods for total inductance calculation of meander inductor are given. By using proposed algorithm, we are able to predict correctly all inductance variations introduced by varying geometry parameters. Our. developed program gives possibility for fast and accurate inductance calculation for meander inductor, while new expression in monomial form is useful for optimization of this inductor. The results validations, given by proposed software tool are conformed by comparison with measured data from literature.

Differential Measurement of Fast Energy Discharge Capacitor, Inductance, and Resistance

A differential method to measure, simply and accurately, the equivalent series inductance (ESL) and the equivalent series resistance (ESR) of energy discharge capacitors is described and compared with other available methods. The differential method measures the ESL over a wide range of inductance, including extremely low inductance values, without elaborate equipment or intricate data interpretation. The differential method also determines the ESR of fast energy capacitors at frequencies approaching the capacitor self-resonant frequency.