Electromagnetic Design Research Articles

Unobstructive and safe-to-wear watt-level wireless charger

A wearable microgrid that centralizes and distributes harvested energy across different body regions can optimize power utilization and reduce overall battery weight. This setup underscores the importance of developing cable-free wireless power transfer (WPT) systems for mobile and portable devices to eliminate the risks posed by wired connections, especially in dynamic and hazardous environments. We introduce a thin, stretchable, and safe hand band capable of watt-level wireless charging through the widely adopted Qi protocol operating at 130 kHz. The implementation of non-adhesive fabric encapsulation serves to protect the 50-μm-thin spiral copper antenna from mechanical strain, ensuring an overall hand band stretchability of 50%. We also create a stretchable “Ferrofabric”, characterized by a magnetic permeability of 11.3 and a tensile modulus of 75.3 kPa, that provides magnetic shielding for the antenna without compromising wearability. The “Ferrofabric” improves the coil inductance but induces core loss in AC application. By fully understanding and managing loss mechanisms such as the skin effect, proximity effect, core loss, and joule heating, we achieve a wireless charging efficiency of 71% and power delivery of 3.81 W in the kHz frequency range. Our WPT hand band is unobstructive to hand motion and can charge a handheld smartphone as fast as a desktop charger or power a battery-free chest-laminated e-tattoo sensor, with well-managed thermal and electromagnetic safety. Through a holistic electromagnetic, structural, and thermal design, our device culminates in a safe, rugged, and versatile solution for wearable WPT systems.

Model Order Reduction Methods for Rotating Electrical Machines: A Review

Due to the rise of e-mobility applications, there is an increased demand to create more accurate control methods, which can reduce the loss in an e-drive system. The accurate modeling of the rotating machines needs to resolve a partial differential equation system that describes the thermal and mechanical behavior of the different parts in addition to the electromagnetic design. Due to these models’ limited resources and high computation demand, they cannot be used directly for real-time control. Model order reduction methods have been of growing interest in the past decades and offer solutions for this problem. According to the processed literature, many model order reduction-based methods are used for a wide range of problems. However, a paper has not been published that discusses a model order reduction-based real-time control model that is actually used in the industry. This paper aims to summarize and systematically review the model order reduction methods developed for rotating electrical machines in the last two decades and examine the possible usage of these methods for a real-time control problem.

Strain analysis and preliminary test of an all-superconducting high-field magnet generating 32.4 T direct-current magnetic field

Abstract A higher available magnetic field can give more flexibility for significant research and constructions. Inserting feasible high-temperature-superconducting (HTS) magnet inside low-temperature-superconducting (LTS) external is becoming an efficient method to build ultra-high-field (UHF) magnets. However, HTS insert magnets exhibited concentration of magnetic strain during the energization, significantly owing to the screening-current effect. This phenomenon affect the structural integrity of HTS magnets, posing a difficulty for UHF magnets to reach a center field larger than 30 T. In this paper, we report the recent progress of the 35 T all-superconducting UHF magnet project. The full-cycle development of this homemade UHF magnet was a strong collaboration with multiple domestic institutions in China. We used commercial REBa2Cu3O7-x (RE = rare earth element, REBCO) conductors to wind the 20 T HTS insert. Specifically, we optimized the electromagnetic design of this HTS insert with consideration of screening-current induced strain. We applied the no-insulation and metal-as-insulation winding techniques simultaneously to balance the time constant of the two nested REBCO coils. During the excitation test, the HTS insert maintained a 256 A operation current as designed for nearly 18 hours. With the energization of LTS external magnet, the entire facility reached a center field larger than 20 T for 16 hours, 30 T for 6.35 hours and 32 T for 2 hours. It finally reached a 32.4 T center field, at which point the LTS external quenched, inducing the HTS insert to quench as well. After quench, the HTS magnet can maintained 229 A operation current during the postmortem standalone test. This 32.4 T result exhibits effectiveness of considering the screening-current induced strain to enhance the structural integrity of REBCO magnets, and verifies the high reliability of REBCO magnets by generating a long-duration high field environment without any quench accident originating from the REBCO magnet.

A wave-transparent electrothermal sandwich composite for high-efficient anti-icing/de-icing

Light-weight composite materials with multifunction are widely used on aircrafts, antennas and wind turbines. Its anti-icing/de-icing is still a great challenge due to its poor heat transmission and low heat resistance. To address these issues, a novel electrothermal sandwich composite (NESC) was prepared by hot pressing an electrothermal film into load-bearing composite materials. By optimizing the ingredient of boron nitride nanoparticle, the heat diffusion rate was improved by 86 %, saving ∼14 % of energy consumption for complete anti-icing in dynamic icing conditions compared to samples without thermal conductivity enhancement. Furthermore, high electromagnetic transmittance up to 80 % of NESC was ensured through electromagnetic design. Besides the high-efficient and electromagnetic compatible anti-icing performance, NESC also performs high resistance to acid/alkali, abrasion and impact, good heating uniformity, stable photothermal effect, and potential of large-area manufacture. This paper presents a promising solution for durable, multi-functional, compatible, and energy-saving composites for anti-icing and de-icing.

Electromagnetic Design and Mechanical Analysis of a 28.2-T/1.2-GHz High-Field NMR Magnet

Electromagnetic Design and Mechanical Analysis of a 28.2-T/1.2-GHz High-Field NMR Magnet

Efficient linear analysis of coupled-cavity traveling-wave tubes using minimum number of dispersion frequency points

Coupled-cavity traveling-wave tubes (CCTWTs) are high-power amplifiers operating in the microwave and millimeter-wave regions of the spectrum, utilizing beam-wave coupling within an electromagnetic slow-wave structure (SWS). The linear (small-signal) analysis of these amplifiers is a crucial initial step in their electromagnetic design. This paper presents and evaluates a method for analyzing these structures in the linear regime using only three frequency points from the SWS. The results obtained from this method are compared with full-wave particle-in-cell simulations, demonstrating satisfactory agreement. This approach offers a rapid analysis method for examining CCTWTs in the linear state, eliminating the need for lumped circuit modeling and detailed knowledge of the SWS dispersion characteristics.

Design, analysis, and optimization of PMSM for ultra-deep water pile hammer application

With the development of global deepwater oil and gas and offshore wind power resources, there is an increasing demand for ultra-deep water pile hammers (UDPH). In this paper, a permanent magnet synchronous motor (PMSM) with oil fill is proposed for UDPH on the basis of underwater 2500 m depth and 450 kJ impact energy requirements. First, the rated parameters of the PMSM are calculated based on the power required by hydraulic pumps, and then, the method of combining empirical formulas and path algorithms is used to complete the electromagnetic scheme design. Second, finite element analysis of the electromagnetic field is carried out by Maxwell under both no-load and load conditions to verify the rationality of the PMSM. Furthermore, aiming at improving efficiency and reducing cogging, parameter optimization is carried out by a robust parameter optimization design method, and the optimal parameter scheme of the PMSM is obtained. In addition, loss analysis and temperature field coupling calculations of the optimized PMSM are conducted to verify that the temperature of this motor can meet the requirements under different working conditions. Finally, a comparative analysis is conducted between the proposed PMSM and the three-phase asynchronous motor used in the underwater 2,500 m-450 kJ UDPH. The results indicate that the new PMSM introduced in this paper demonstrates significant advantages in terms of weight, volume, and efficiency; moreover, the new PMSM is reasonable and more suitable for UDPH. Therefore, the PMSM proposed in this paper is reasonable and can provide a theoretical basis for improving the traditional UDPH.

Improvement of titanium film uniformity by magnetron sputtering with electromagnetic coil design

A novel magnetron assembly based on a combination of permanent magnet and adjustable electromagnetic coil is proposed for improved uniformity of the magnetron sputtering deposition process. The design of the magnetron sputtering system containing a rotating substrate and an off-axis arranged magnetron. A numerical framework has been developed to describe the evolution of the plasma density and distribution of sputtered particles. Specifically, the finite element method (FEM) was used to calculate the magnetic field and to model the magnetron sputtering discharge, and binary-collision Monte Carlo method was used to determine the transport of sputtered atoms to the substrate. Through parametric analyses, it was found that increasing the substrate-to-target distance, gas pressure, and coil current intensity benefits the uniform distribution of particles. The condition where the off-axis displacement of the magnetron effectively enhances uniformity. A strategy for optimizing deposition uniformity by combining adjustable current with an off-axis magnetron arrangement was proposed, which reduce the non-uniformity of film thickness by 77.6 % compared to the traditional fixed magnetic field model.

Control System Hardware Design, Analysis and Characterization of Electromagnetic Diaphragm Pump

In this article, a novel electromagnetic diaphragm pump design controlled by an Arduino NANO microcontroller is proposed to pump liquid inside the pumping chamber completely separated from mechanical and transmission parts. The prototype is primarily based on alternating the polarity of two electromagnets that attract or repel a permanent magnet located on a flexible diaphragm. The system hardware layout is completed by electronic components:. an Arduino NANO microcontroller created by Atmel, Headquarters San Jose, California. and display within the cabinet to control the polarization of the electromagnets and exhibit the temperature inside the pump. The electromagnetic pump and control system consist of innovative approaches as a solution for the treatment of unclean water and integration with solar panel systems. In addition, the measurement tests of the electromagnetic pump, including the temperatures of electromagnets and the quantity of the pumped liquid within the chamber, indicate a dependence on the selected speed of the electromagnet’s polarization. The electromagnetic pump achieves high efficiency as a combination of the temperature and the amount of liquid that can be regulated and controlled by the switching speed of the electromagnet’s polarization.

Square & H metasurfaces for SPR Increasing in long Wave-IR absorber

In the long-wave infrared (LWIR) spectrum, this paper suggests an electromagnetic (EM) waveband absorber design based on metamaterials. Germanium, gold, and magnesium oxide layers are arranged in a layered structure from top to bottom in the suggested model. Our proposed metamaterial structure’s upper surface is composed of metallic metasurfaces with H and square forms from various studies. The finite element method is used to evaluate the metamaterials’ electromagnetic properties in terms of absorbance and reflectance. It is observed that there is a particular size of the metamaterial at which extremely localized electromagnetic resonance occurs. Quantitative findings indicate that the suggested metamaterial design’s average absorption reaches 90 % in the 10 μm to 14 μm range across a wide variety of incidence angles (00 to 400 & 00 to 800) for both transverse electric (TE) and transverse magnetic (TM) polarization. It is evident from these data that the suggested model configuration has broad potential applications in manyoptoelectronic fields of study.

Innovative design to achieve a multi-band electromagnetic wave stealth.

Metamaterials have opened up a new field of electromagnetic wave stealth that can achieve cross-band electromagnetic wave stealth through high electromagnetic wave absorption and low infrared emission. However, traditional cross-band stealth metamaterials make covering the terahertz band challenging and have certain design flaws. This Letter introduces an innovative cross-band electromagnetic wave stealth metasurface design that can achieve cross-band stealth in the infrared, microwave, and THz bands. We use phase change materials and the gradient principle to achieve GHz and THz cross-band absorption. We also design surface height-covered low infrared emitting materials, which give them lower infrared emissivity. These functions give it enormous potential in military applications, and using phase change materials for cross-band absorption also provides new, to our knowledge, ideas for multifunctional stealth materials.

FEA-based pole arc optimization and sensitivity analysis of 8/6 SRM for EV application

The optimization of the pole arcs and sensitivity analysis of a 4-phase 8/6 Switched Reluctance Motor (SRM) using the Finite Element Analysis (FEA) technique for the Electric Vehicle (EV) application is presented in this article. The motor's power rating is estimated from the tractive force of an e-rickshaw(3-wheeler). Optimizing the pole arc in SRMs is essential for obtaining an optimal balance of performance, efficiency, and operating smoothness. This makes it a vital part of SRM design. The motor performance is analyzed by fixing the stator pole arc while varying the rotor pole arc and vice versa. The main performance attributes like torque, torque ripple, torque per rotor volume, and efficiency of an 8/6 SRM with various pole arc values are examined using the transient FEA method. A sensitivity analysis is conducted to evaluate the range of variation in the performance parameters of the motor when the pole arcs vary. Various performance indices, such as torque, torque ripple (TR), efficiency, and Torque Per Volume (TPV), are considered for the analysis. The sensitivity analysis is carried out based on the transient analysis. Finally, based on the findings, the optimal combination of pole arcs is determined and analyzed the performance using the FEA method. An electromagnetic design tool called Infolytica MOTORSOLVE is used to construct the FEA models and extract the characteristics.

Conjointly active and passive modelings with deep neural networks as fully automated optimizations for upper-mid band 6G communications

Today wireless systems include the fifth and sixth generations (5G and 6G) technologies and are growing day by day that result in exponentially increasing data traffic. For providing a reliable and high performance radio frequency (RF) designs especially for 6G networks, amplifiers and antenna as active and passive components play important roles. In the 5G/6G communication systems, the propagation loss is considerably large and its compensation requires high output power generated from the amplifiers for guaranteeing the satisfied quality of transmitted signal. From another point of view, the installed antennas must be able to optimally manage the radiated signals and handle/compensate nonlinear performances of the RF circuitry. Hence, advanced modeling and multi-objective optimization algorithms are required for designing and optimizing high performance amplifiers and antennas in terms of output power, gain, efficiency, linearity, and bandwidth. Concurrently optimizing active and passive components is not straightforward and typically it requires additional efforts by the RF designers. To tackle this drawback, a two-step methodology is proposed: (1) configuring the initial structure of active and passive devices, and (2) sizing the configured devices. In this work, various methods are introduced for structuring the topology of circuits and then artificial intelligence, including machine learning and neural networks, is preferred among other surrogate modelling for sizing the designs. These neural networks are satisfied due to the accurate modeling responses and are able to provide an automated optimization process leads to employ multi-objective optimization methods. In this work, an automated optimization process for comprehensive design of high-performance amplifiers with antennas through bottom-up optimization (BUO) method and long short-term memory (LSTM)-based deep neural networks (DNNs) is proposed. At the output layer of DNNs, the multi-objective multi-verse optimizer (MOMVO) method is employed for optimizing various specifications of active device (i.e., amplifier), and passive device (i.e., antenna), concurrently. In the presented method, all the electromagnetic (EM) design rules are implemented which results in reducing simulation time in the harmonic balance simulation environment that also provides ready to fabricate layouts. The novelty consists of the all-inclusive style that (1) reduces the manual breaks, aka time-to-market, and (2) delivers ready-to-fabricate layouts of the device that exhibits global optimum performances, automatically. The validation of the proposed method is verified by designing and optimizing high power amplifier (HPA) with antenna in the frequency band from 9.0 GHz to 9.6 GHz, suitable for upper-mid band 6G communications.

Electromagnetic and Thermomechanical Design Method of Graded Dielectric Streamlined Radome Accelerated by Artificial Intelligence

Electromagnetic and Thermomechanical Design Method of Graded Dielectric Streamlined Radome Accelerated by Artificial Intelligence

Electromagnetic Design of a REBCO Four-Pole Full-Pitched Armature Coil Composed of Trapezoidal Windings for Fully Superconducting Synchronous Motors

Electromagnetic Design of a REBCO Four-Pole Full-Pitched Armature Coil Composed of Trapezoidal Windings for Fully Superconducting Synchronous Motors

RF electromagnetic design and field tuning study of the coupled ladder RFQ-IH DTL structure

The coupled ladder RFQ-IH DTL structure is designed for transportable accelerator-based neutron source to accelerate the proton beam to 2.5 MeV with a peak current of 15 mA. The Kombinierte Null Grad Struktur (KONUS) dynamics scheme is chosen in the IH-DTL section to obtain compact structure, high transmission efficiency and small emittance growth. Three KONUS periods, including two quadrupole doublets are housed in the IH-DTL section. The field distribution of coupled structure is studied and the evaluation of the coupled field is quantified. The optimization voltage ratio and electric flatness are carried out based on three-dimension full model. In addition, the structure error analysis is performed to evaluate the acceptance of different errors. The tuning system is designed to compensate the machining and alignment errors and the field tuning strategy is proposed for the coupled cavity. The RF electromagnetic design and optimization, structure error analysis and field tuning will be comprehensively presented in this paper.

Electromagnetic design of high-temperature superconducting electrodynamic suspension magnets

This paper introduces the electromagnetic design process for high-temperature superconducting (HTS) magnets used in electrodynamic suspension (EDS) systems. First, the winding process and detailed parameters of the magnets are described. Then, based on the full-field angle characteristic method, the critical current of the magnets is evaluated and the operating current is determined. Finally, the magnetic field distribution and charging delay of the magnets are assessed based on the design results. This paper provides a reference for the electromagnetic design of superconducting electromagnetic suspension magnets.

A 10 µH Inductance Standard in PCB Technology with Enhanced Protection against Magnetic Fields

Low-frequency working standards of inductance are generally uniformly wound toroids on a ceramic core. Planar inductors made using printed circuit board (PCB) technology are simple and cheap to manufacture in comparison to inductors wound on toroid cores, but they are significantly prone to the influence of external magnetic fields. In this paper, we propose the design of a PCB inductance working standard of 10 μH, consisting of a duplex system of planar PCB coils, electrostatic shielding, and an enclosure. Alongside an electromagnetic analysis and design procedure, the measurements on the manufactured prototype included the generated magnetic field, the thermal time constant of the enclosure, temperature coefficients, and its error analysis. The measurements show negligible generated magnetic fields (<1.68 nT at 7 cm, 49 mA, 10 kHz). The minimum thermal time constant of the enclosure is 1270 s and the temperature coefficient of resistance is 0.00384 1/℃. The presented method of temperature coefficient measurement using a climate chamber allows for measurements in the temperature range of 10 °C to 40 °C. In this temperature range, the results show an inductance variation of 0.05 µH at 50 kHz, while the uncertainty of inductance measurement at this frequency was 0.03 µH (k = 2).

Study the potential of micro laser sintering additive manufacturing technology for metallic 3D printing horn antenna structure

AbstractApplications for an antenna structure produced with additive manufacturing technology are numerous and promising. This study focuses explicitly on utilizing micro‐laser sintering (MLS) three‐dimensional (3D) printing technology to fabricate two rectangular horn antennas identical to a standard Pasternack® horn antenna, making the fabrication straightforward. The objective is to investigate how surface roughness affects antenna performance in a frequency range of 18 to 26.5 GHz. One antenna is polished and the other is left untouched, resulting in surface roughness of 4 and 6 µm, respectively, measured using a profilometer. Then, a vector network analyzer was used to assess their reflection coefficient, transmission characteristics, and radiation pattern and determine gains of 8.83 and 9.14 dBi for the polished and unpolished antennas, respectively. The study finds that both polished and unpolished antennas perform similarly, and their characteristics closely resembling simulated and standard antennas. Finally, the performance of the MLS‐printed metallic antennas is compared with horn antennas created using other 3D printing techniques. It reveals that the MLS‐printed metallic structures exhibit better performance, indicating that the MLS technology has great potential to print 3D metallic electromagnetic designs.

Optimization of electromagnetic layout for E-machine in electric vehicles: Achieving high performance, efficiency and NVH

The development of electric vehicles (EVs) presents the challenge of optimising electric machines to enhance efficiency, compactness, noise, vibration, harshness (NVH), and affordability, while reducing the dependence on heavy rare-earth materials to reduce the CO2 footprint of electric powertrains. This paper introduces a comprehensive optimization approach for the electromagnetic design of permanent magnet synchronous machines (PMSMs), employing a combination of Design of Experiment (DoE) and Robust Neural Networks (RNN). The optimization framework is utilised to comprehensively address the multiple objectives of an electric machine, including efficiency, noise, vibration, harshness (NVH), and cost. The integration of Artificial Intelligence (AI)-driven modelling has resulted in significant performance improvements, achieving up to 96% total efficiency over the entire load cycle with substantial NVH reductions of up to 20 dB, while reducing the magnet rare earth materials by 35% compared to the baseline. Furthermore, this methodology reduces the simulation time by up to 90%, demonstrating the potential of combining neural network optimization with conventional finite element simulation techniques. The validation of the AI-driven optimization approach with the measurement of the baseline and optimised electric machines for efficiency and vibration is demonstrated for correlation.