Power Adaption Design for Multifrequency Wireless Power Transfer System

The warpage of individual IC panel/package or whole molded strips keeps changing with temperature during the assembly processes from die bonding, wire bonding, molding, post-mold cure to soldering reflow. How to optimize package design and properties of all assembly materials to obtain acceptable warpage level both at room temperature and reflow temperature becomes more challenging. In this study, finite element analysis (FEA) simulation was performed in warpage prediction of three types of advanced laminated IC packages (PBGA, CSP BGA and PoP BGA). Shadow Morie system was used in monitoring warpage deviation under temperature profile from -55degC to 260degC. Calibration or correction of FEA results can be performed by introducing experimental results from Shadow Morie measurement to fine-tune the modeling so as to obtain more accurate prediction

With the development of inductive wireless power transfer technology (IPT), electromagnetic compatibility (EMC) of the IPT system has attracted much attention. In this paper, the equivalent AC impedance model of LCC/S topology is established, and the conclusion that the output characteristics and power transfer efficiency (PTE) are related to mutual inductance M is obtained. To solve the problem of excessively large magnetic flux leakage of loosely coupling transformer (LCT), magnetic coupler with vertical and horizontal shielding is designed based on the method of magnetic flux constraint, and its finite element analysis (FEA) 3D model is established. A prototype is built for experiments. The maximum transmission efficiency of the prototype is 90.33%, and the minimum transmission efficiency is 88.20%. The FEA simulation and experimental results verify the feasibility of the magnetic shielding structure design method. The results show that the novel proposed magnetic shielding structure increases the strength of magnetic field, effectively reduces the eddy current loss caused by magnetic field leakage, and increases the anti-misalignment ability of the system.

Although a compliant gripper is a type of compliant mechanism, existing analytical models rarely account for the real mechanical behavior of the flexible parts within the gripper. In this work, an in-plane motion flexure-based compliant gripper is presented, modeled, and analyzed. An analytical methodology based on the Compliance Matrix Method (CMM) is proposed to compute the relationship between input and output forces and displacements in two different coordinate frames using a single unified expression that represents the real mechanical behavior of the system. The analytical model is validated through Finite Element Analysis (FEA) simulations and experimental tests performed on additively manufactured prototypes. Additionally, the model is used to analyze output displacements resulting from variations in geometric parameters, with results validated through FEA simulations. This demonstrates the method’s utility in optimizing gripper design during early development stages prior to fabrication. The proposed analytical model accurately estimates the compliant gripper’s kinetostatic behavior, achieving less than 5% difference compared to FEA and experimental results. Furthermore, the model is adaptable and can be extended for the kinetostatic analysis of other compliant grippers with similar flexure-based architectures.

Acoustic emission (AE) testing and Lamb wave inspection techniques have been widely used in non-destructive testing and structural health monitoring. For thin plates, the AEs arising from structural defect development (e.g., fatigue crack propagation) propagate as Lamb waves, and Lamb wave modes can be used to provide important information about the growth and localisation of defects. However, few sensors can be used to achieve the in situ wavenumber–frequency modal decomposition of AEs. This study explores the ability of a new multi-element piezoelectric sensor array to decompose AEs excited by pencil lead breaks (PLBs) on a thin isotropic plate. In this study, AEs were generated by out-of-plane (transverse) and in-plane (longitudinal) PLBs applied at the edge of the plate, and waveforms were recorded by both the new sensor array and a commercial AE sensor. Finite element analysis (FEA) simulations of PLBs were also conducted and the results were compared with the experimental results. To identify the wave modes present, the longitudinal and transverse PLB test results recorded by the new sensor array at five different plate locations were compared with FEA simulations using the same arrangement. Two-dimensional fast Fourier Transforms were then applied to the AE wavefields. It was found that the AE modal composition was dependent on the orientation of the PLB direction. The results suggest that this new sensor array can be used to identify the AE wave modes excited by PLBs in both in-plane and out-of-plane directions.

Enhancing power density and reliability of power electronics is extremely important in power electronics applications. One of the key challenges in the design process is to design the optimum heat sink. In this paper, an algorithm is proposed to design air-cooled heat sinks using genetic algorithm (GA) and finite element analysis (FEA) simulations. While the GA generates a population of candidate heat sinks in each iteration, FEA simulations are used to evaluate the fitness function of each. The fitness function considered in this paper is the maximum junction temperature of the semiconductor devices. With an approach that prefers “survival of the fittest”, a heat sink providing better performance than the conventional heat sinks is obtained. The simulation and experimental evaluations of the optimized air-cooled heat sink are also included in the paper.

Recent developments in Generative AI enable creators to stylize 3D models based on text prompts. These methods change the 3D model geometry, which can compromise the model’s structural integrity once fabricated. We present MechStyle, a system that enables creators to stylize 3D printable models while preserving their structural integrity. MechStyle accomplishes this by augmenting the Generative AI-based stylization process with feedback from a Finite Element Analysis (FEA) simulation. As the stylization process modifies the geometry to approximate the desired style, feedback from the FEA simulation reduces modifications to regions with increased stress. We evaluate the effectiveness of FEA simulation feedback in the augmented stylization process by comparing three stylization control strategies. We also investigate the time efficiency of our approach by comparing three adaptive scheduling strategies. Finally, we demonstrate MechStyle’s user interface that allows users to generate stylized and structurally viable 3D models and provide five example applications.

Wireless power transfer (WPT) systems for Electric Vehicles (EVs) are designed to meet specifications such as stray field, power transfer, efficiency, and ground clearance. Typical design approaches include iterative analysis of predetermined coil geometries to identify candidates that meet these constraints. This work instead directly generates WPT coil shapes and magnetic fields to meet specifications and constraints through the optimization of Fourier basis function coefficients. The proposed Fourier Analysis Method (FAM) applies to arbitrary planar coil geometries and does not rely on iterative finite-element analysis (FEA) simulations. This flexibility allows for rapid design evaluation across a larger range of coil geometries and design specifications. A prototype coil is built to compare FAM outputs to experimental measurements and FEA simulations. The FAM is then used to illustrate the tradeoff of coil current and stray field for a given power level showing that the method is capable of generating optimized coil shapes to meet arbitrary field constraints.

This article presents the theoretical analysis and numerical modeling of various cogging torque suppression methods of the slotted limited angle torque motor (LATM). The relationship between the cogging torque, the output characteristics, and the structure parameters of new methods is revealed by derived equations and finite-element analysis (FEA), which provides a theoretical basis for the optimization of the slotted LATM. The effectiveness of the best suppression method is verified by the prototype experiment. In addition, a method to predict torque distortion caused by armature reaction is proposed and it is verified by the finite-element simulation and prototype experiment.

Conventional finite element analysis (FEA) performed in electromagnetic-vibration coupling calculation of motor suffers from several significant drawbacks, such as large memory space, high computational cost and heavy reliance on mesh quality for accurate solution. With the traditional meshless method, special attention needs to be paid to correctly impose the boundary condition like FEA. Besides, the matrix is easily prone to be ill-conditioned due to introducing large amount of higher-order basis functions. We propose a novel multi-physical coupling method combining FEA and optimized meshless method. The proposed methodology is further evaluated on the vibration analysis of a 12-slot 10-pole permanent magnet synchronous motor (PMSM). Firstly, 2D stator electromagnetic force is simulated and derived based on the local Jacobian derivative method through FEA. The electromagnetic force spectrum is calculated using FFT analysis and further imported into commercial meshless structural simulation software SimSolid for stator harmonic response analysis. Correct force boundary condition and data mapping between meshless and FEA simulation interface are key to the accuracy of the proposed combined multi-physical modeling methodology. This is achieved by introducing new high-dimensional ramp function in the transition region between FEA and meshless domains, which are defined with the shape functions composed of the FEA and meshless method. This function satisfies the continuity and consistency of the displacement function and ensures the convergence of coupled FEA-meshless method. Subsequently, construction of basis function is key to the establishment of convention meshless discrete equation for the elastic problem of rotating machinery. This is designed by using moving least square theory in cylindrical coordinate system. A harmonic response with meshless method is analyzed by using the mode superposition method to obtain detailed mode shape data, acceleration and displacement distribution of stator. Finally, the tangential continuity and robustness are not well considered in the traditional simulation with FEA coupled meshless method. To mitigate this problem, we propose an optimized meshless method based on modified local basis functions to recalculate the harmonic response motion. Then, the coupling electromagnetic-vibration simulation results of traditional coupled FEA-meshless method, optimized coupled FEA-meshless method and complete FEA coupled method are compared. It is worth noting that the optimized method significantly improves accuracy, robustness and computational speed at the same time. In short, the proposed electromagnetic-structure coupling calculation method provides a novel alternative for the multi-physical coupling calculation of rotating machinery combining FEA and meshless simulation methods.

An energy-efficient high-powermulti-coil wireless power transfer system (WPT) has been studied in this paper. The proposed system was first analyzed and examined using theoretical modeling; this was followed by finite element analysis and circuit simulation to confirm the goal. As the air gap between the transmitter and receiver coils widens, the coupling coefficient of a WPT system will drop. A large-air-gap WPT system’s coupling coefficient can be raised by adding relay coils between the transmitting and receiving coils. On the other hand, an increased coupling coefficient improves the system’s overall power transfer efficiency. The suggested multi-coil system, which has an air gap of 15 cm and a lateral misalignment of 3 cm between the transmitting and receiving coils, has been simulated and verified using the Maxwell 3-D finite element tool and Ansys Simplorer circuit simulation software.

This paper proposes a new design concept of small air-gap bidirectional Wireless Power Transfer (WPT) system using Dual Active Bridge (DAB) topology. The wireless charging coils are considered as a weakly coupled transformer having relatively high leakage inductance, and thus the new design can obtain soft switching without implementing resonant capacitor or external inductor. This design has a simple construction and can enable bidirectional inductive power transfer with superior performance compared to the traditional large air-gap system. The new system can transfer high power via a compact coil structure thanks to smaller air gap. Moreover, soft-switching operation enables significant improvement in efficiency. The proposed design enables electrical vehicles and smart wheels to use batteries for supporting grid silently and seamlessly. This paper considers the application of smart wheel charger and presents an analytical design of the system using finite element analysis and circuit simulation. As a result, the design can achieve 97% efficiency at 3-kW, 85-kHz operation.

Optimal parameter selection is a crucial step in improving the quality of electronic packaging processes. Traditional approaches usually start with a set of physical experiments and then employ Design of Experiment (DOE) based response surface methodology (RSM) to find the parameter settings that will optimize a desired system response. Nowadays deterministic computer simulations such as Finite Element Analysis (FEA) are often used to replace physical experiments when evaluating a system response, e.g., the stress level in an electronic packaging. However, FEA simulations are usually computationally expensive due to their inherent complexity. In order to find the optimal parameters, it is not practical to use FEA simulations to calculate system responses over a large number of parameter combinations. Nor will it be effective to blindly use DOE-based response surface methodology to analyze the deterministic FEA outputs. In this paper, we will utilize a spatial statistical method (i.e., the Kriging model) for analyzing deterministic FEA outputs from an electronic packaging process. We suggest a sequential method when using the Kriging model to search for the optimal parameter values that minimize the stress level in the electronic packaging. Compared with the traditional RSM, our sequential parameter selection method entertains several advantages: it can remarkably reduce the total number of FEA simulations required for optimization, it makes the optimal solution insensitive to the choice of the initial simulation setting, and it can also depict the response surface and the associated uncertainty over the entire parameter space.

A novel multimodal piezoelectric energy harvester with rotating-DOF for low-frequency vibration

Wireless power transfer in seawater removes the inherent risks and complexities of mating conductive surfaces in seawater. An effective underwater wireless power transfer system for subsea vehicles must maintain power transfer despite the potential for dynamic misalignment between the power transmission and receive elements and therefore requires an adaptive system. We describe the development and characterization of a subsea wireless power system, including a transmit-receive coil pair optimized for seawater performance. Built on the adaptive resonant wireless power transfer technology of WiBotic, Inc., the system automatically adjusts for misalignment and separation between the transmit and receive coils. We demonstrate that transmit-receive coil pairs can be effectively tuned to provide adaptive wireless power transfer in salt water, with no significant effects of increased pressure at depth. Furthermore, we describe the full system marinization of the wireless power system and its application to a system that uses a wave energy converter for subsea vehicle charging.

PowerSynth is a multiobjective optimization tool for rapid design and verification of power semiconductor modules. By using reduced order models for the calculation of electrical parasitics of the layout and thermal coupling between devices, optimal trace layout and die placement can be simultaneously achieved orders of magnitude faster than conventional finite element analysis (FEA) techniques. An overview of the tool, its modeling methods, model validation, and module layout optimization are presented. The electrical and thermal models are validated against FEA simulations and physical measurements of built modules generated from the tool. The FEA comparisons are performed with FastHenry and ANSYS Icepak to evaluate electrical parasitics and thermal behavior, respectively. A sample hardware prototype based on a half-bridge circuit topology is chosen for testing. Excellent agreement between the FEA simulations, experimental measurements, and PowerSynth predictions are demonstrated. Additionally, when compared with conventional simulation runtime and workflow, PowerSynth takes considerably less computation and user time to produce several candidate layout solutions from which a designer may easily balance selected tradeoffs.