Wireless power transfer (WPT) technology is a promising way for convenient and safe battery charging without any electrical contact, which may cause an unwanted electric spark or deliver dangerous ...electric current to the users. When transferring power from the source to the battery, strong electromagnetic fields (EMFs) are generated. Moreover, the inverter output contains a wide range of harmonics. Therefore, it is important to reduce the EMFs and electromagnetic interference (EMI) in a WPT system. For the first time, in this paper, we propose a new tightly coupled three-phase resonant magnetic field (TC-TPRMF) charger for a drone operating at 60 kHz, which can completely eliminate the third harmonic and its integer multiples in the output voltage. Furthermore, to reduce the selective EMI, the conduction angle control is proposed for the WPT charging system. Through a series of measurements, we verified that the proposed TC-TPRMF with the conduction angle control can reduce the seventh and 11th harmonics of the Tx current by 6.08 and 11.84 dBμA, respectively. The coil-to-coil power transfer efficiency and total system power transfer efficiency are maintained at 91% and 72%, respectively.
For wireless charging of electric vehicle (EV) batteries, high-frequency magnetic fields are generated from magnetically coupled coils. The large air-gap between two coils may cause high leakage of ...magnetic fields and it may also lower the power transfer efficiency (PTE). For the first time, in this paper, we propose a new set of coil design formulas for high-efficiency and low harmonic currents and a new design procedure for low leakage of magnetic fields for high-power wireless power transfer (WPT) system. Based on the proposed design procedure, a pair of magnetically coupled coils with magnetic field shielding for a 1-kW-class golf-cart WPT system is optimized via finite-element simulation and the proposed design formulas. We built a 1-kW-class wireless EV charging system for practical measurements of the PTE, the magnetic field strength around the golf cart, and voltage/current spectrums. The fabricated system has achieved a PTE of 96% at the operating frequency of 20.15 kHz with a 156-mm air gap between the coils. At the same time, the highest magnetic field strength measured around the golf cart is 19.8 mG, which is far below the relevant electromagnetic field safety guidelines (ICNIRP 1998/2010). In addition, the third harmonic component of the measured magnetic field is 39 dB lower than the fundamental component. These practical measurement results prove the effectiveness of the proposed coil design formulas and procedure of a WPT system for high-efficiency and low magnetic field leakage.
In this paper, we introduce the basic principles of wireless power transfer using magnetic field resonance and describe techniques for the design of a resonant magnetic coil, the formation of a ...magnetic field distribution, and electromagnetic field (EMF) noise suppression methods. The experimental results of wireless power transfer systems in consumer electronics applications are discussed in terms of issues related to their efficiency and EMF noise. Furthermore, we present a passive shielding method and a magnetic field cancellation method using a reactive resonant current loop and the utilization of these methods in an online electric vehicle (OLEV) system, in which an OLEV green transportation bus system absorbs wireless power from power cables underneath the road surface with only a minimal battery capacity.
The 3-D integration helps improve performance and density of electronic systems. However, since electrical and thermal performance for 3-D integration is related to each other, their codesign is ...required. Machine learning, a promising approach in artificial intelligence, has recently shown promise for addressing engineering optimization problems. In this paper, we apply machine learning for the optimization of 3-D integrated systems where the electrical performance and thermal performance need to be analyzed together for maximizing performance. In such systems, modeling can be challenging due to the multiscale geometries involved, which increases computation time per iteration. In this paper, we show that machine learning can be applied to such systems where multiple parameters can be optimized to achieve the desired performance using the minimum number of iterations. These results have been compared with other promising optimization methods in this paper. The results show that on an average, 4.4%, 31.1%, and 6.9% improvement in temperature gradient, CPU time, and skew are possible using machine learning, as compared with other methods.
In this article, we propose a double-sided electromagnetic bandgap (DS-EBG) structure for glass interposers (GIs) with low substrate loss to suppress power/ground noise. For the first time, we ...validated wideband power/ground noise suppression in the GI using the proposed DS-EBG structure based on dispersion analysis and experimental verification. We experimentally verified that the proposed DS-EBG structure achieved the power/ground noise suppression (below −40 dB) between 2.5 and 8.9 GHz in the GI. Derived stopband edges, <inline-formula> <tex-math notation="LaTeX">f_{L} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">f_{U} </tex-math></inline-formula> based on the dispersion analysis, and 3-D electromagnetic (EM) simulation showed a good correlation with measurements. The effectiveness of the proposed DS-EBG structure on the power/ground noise suppression is verified by analyzing noise propagation in the power distribution network and coupling to the GI channel. Using the 3-D EM simulation, we verified that the proposed DS-EBG structure suppressed the power/ground noise coupling and improved the eye diagram of the GI channel. Finally, we propose a design methodology to broaden the isolation bandgap or miniaturize the dimensions based on the dispersion analysis.
Current wireless power transfer (WPT) technology can only allow power transfer over a limited distance because, as the distance between the transmitter (Tx) and receiver (Rx) coils increases, the ...power transfer efficiency (PTE) decreases with a steep slope, while the electromagnetic field (EMF) leakage increases. In order to increase the PTE and decrease the EMF leakage simultaneously, we need to develop a method to concentrate the magnetic fields between the Tx and Rx coils. In this paper, we proposed a novel metamaterial structure to realize high efficiency and low EMF leakage. Metamaterials can confine the magnetic fields between the Tx and Rx coils by negative relative permeability. We designed and fabricated a thin metamaterial using a 1.6-mm dual layer printed circuit board (PCB) with a high dielectric constant substrate and a fine pattern to achieve a negative relative permeability with low loss at 6.78 MHz. The thin PCB-type metamaterial has a wide range of applications with low fabrication cost, light weight, and a simple fabrication process. We demonstrated a 44.2% improvement in the PTE and 3.49-dBm reduction in the EMF leakage around the WPT system at 20-cm distance. Furthermore, we first analyzed metamaterials from an EMF point of view using the 3-D magnetic field scanner. Finally, we discussed a combination of metamaterials and ferrites to further improve the PTE and reduce the EMF leakage for long-distance mobile WPT systems.
Wireless power transfer (WPT) technology has recently emerged as an innovative and promising technology, and its electromagnetic compatibility (EMC) has become a significant issue. In this study, we ...investigated the electromagnetic (EM) radiated emission and interference generated by WPT systems using resonant magnetic field coupling, especially in applications with multi-coil configurations. The change in coil resonance associated with multi-coil configurations was analyzed via the impedance profile. We measured the EM radiated emission and analyzed the results with respect to the coil resonance. An analog-to-digital converter chip was designed and fabricated to analyze the effect of electromagnetic interference (EMI). Based on measurement and simulation results, we verified that the EM radiated emission and interference increase at the series or parallel resonance peaks, depending on the source type. In addition, we verified that EMI can be reduced by using ferrite sheet shielding.
In this article, we propose a novel statistical eye-diagram estimation method considering nonlinear power/ground noise induced by parallel simultaneous switching output (SSO) buffers. Probability ...density functions (pdfs) of output step-responses affected by the SSO are derived based on the occurrence probability of each SSO pattern. From the derived output response pdfs, main-cursor (MC) pdfs and intersymbol interference (ISI) pdfs are defined. Statistical output responses are derived based on recursive convolution between the MC-pdfs and ISI-pdfs affecting each other. The proposed method, for the first time, considers steady-state responses affected by the SSO to estimate more accurate statistical eye-diagrams. The proposed method is verified by comparing the derived statistical eye-diagrams with eye diagrams obtained using full transient simulation. Also, bit error rate (BER) bathtub curves derived using the proposed method and full transient simulation are compared for verification. The proposed method is compared with the previous study to emphasize importance of the steady-state responses. Finally, the proposed method is expanded to consider previous bit patterns, which are also affected by the SSO.
In this article, we propose a near field analytical model of an electromagnetic interference reduction method using an n th harmonic frequency shielding coil with efficiency enhancement in a loosely ...coupled automotive wireless power transfer system. In general, in the loosely coupled automotive wireless power transfer system, the power transfer efficiency is relatively lower than a tightly coupled wireless power transfer system due to the low coupling. In addition, the electromagnetic interference at the n th harmonic frequency from the power source can interfere with nearby electronic devices. To reduce electromagnetic interference level and enhance efficiency, we proposed a shielding coil between a transmitter and a receiver coil. By using a near field analytical model of the magnetic field intensity and efficiency equations, we analyze based on the equations and obtain a proper value of the resonant frequency of the shielding coil. Therefore, we can achieve low levels of electromagnetic interference at the specific n th harmonic frequency and higher value of the power transfer efficiency in the loosely coupled automotive wireless power transfer system.
We propose a high-frequency scalable electrical model of a through silicon via (TSV). The proposed model includes not only the TSV, but also the bump and the redistribution layer (RDL), which are ...additional components when using TSVs for 3-D integrated circuit (IC) design. The proposed model is developed with analytic RLGC equations derived from the physical configuration. Each analytic equation is proposed as a function of design parameters of the TSV, bump, and RDL, and is therefore, scalable. The scalability of the proposed model is verified by simulation from the 3-D field solver with parameter variations, such as TSV diameter, pitch between TSVs, and TSV height. The proposed model is experimentally validated through measurements up to 20 GHz with fabricated test vehicles of a TSV channel, which includes TSVs, bumps, and RDLs. Based on the proposed scalable model, we analyze the electrical behaviors of a TSV channel with design parameter variations in the frequency domain. According to the frequency-domain analysis, the capacitive effect of a TSV is dominant under 2 GHz. On the other hand, as frequency increases over 2 GHz, the inductive effect from the RDLs becomes significant. The frequency dependent loss of a TSV channel, which is capacitive and resistive, is also analyzed in the time domain by eye-diagram measurements. Due to the frequency dependent loss, the voltage and timing margins decrease as the data rate increases.
