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In this paper, a Witricity-based high-power device is proposed for wireless charging of electric vehicles. According to the specific requirements of three-stage charging for electric vehicles, four compensation modes of theWitricity system are analyzed by the Loosely Coupled Theory among transformer coils and the Substitution Theorem in circuit theory. In addition, when combining voltage withstand levels, the current withstand capability, the switching frequency of electronic switching tubes, and the features of the resonant circuit, the series-parallel (SP) compensation mode is selected as the best compensation mode for matching the capacitor of the system. The performances of coils with different ferrite core arrangements are compared by simulations and models. The feasibility of the system is verified theoretically and the system functions are evaluated by the joint simulation of Simplorer and Maxwell. Finally, aWitricity-based high-power device is proposed as designed, and the correctness of theoretical analyses and simulation results are verified. [ABSTRACT FROM AUTHOR]

• A super-heating efficiency strategy for optimization of induction heating processes by focusing inner magnetic of coil is proposed. • Nearly 6.5-fold of the energy was saved by the focused induction heating method of the FIHM, comparing the traditional induction heating method. • A detailed effect mechanism for six structural parameters of FIHM on temperature and magnetic field is studied. • An experiment is carried out to verify the accuracy of optimization analysis and engineering feasibility. Induction heating has been widely applied in the energy and manufacturing industry for its energy-saving, low-cost, local high-efficiency heating, and noncontact benefits. However, the energy efficiency of the induced magnetic field is normally limited for the magnetic scattering effect. To improve the energy and hence heating efficiency, a focused induction heating method (FIHM) has been proposed in this work by using the conical ferrite to focus inner magnetic of the coil. Meanwhile, a numerical model has been established to predict the electromagnetic and thermal distribution during the FIHM process. Traditional induction heating head and two focused induction heating heads (solid ferrite head and drilled-ferrite head) are compared to reveal the influence mechanism of different induction heating heads on the soldering of the pin-through-hole. The results show that the FIHM with drilled-ferrite head can improve the heating efficiency significantly by approximately 6.5-fold when compared to traditional induction heating, leading to a corresponding outstanding temperature increase over 296 °C within 1.5 s. Furthermore, the detailed effect mechanism for the six structural parameters of the FIHM on the temperature and magnetic field is studied. This study finds that the distance from the ferrite to the tin ring has the most significant effect, causing a temperature difference of about 560 °C. Finally, all these findings have been validated by the soldering experiments, and robust interconnection of deep pin-through-hole joints has been achieved through FIHM without voids. The work provides a theoretical basis and practical guidance for induction heating techniques with excellent electromagnetics and engineering application potential. [ABSTRACT FROM AUTHOR]

Magnetically Insulated Line Oscillator (MILO) is a relatively new type of coaxial crossed field electron beam device, which is designed specifically to generate microwave power at the gigawatt level. Unlike other crossed-field microwave sources, the MILO uses self-magnetic field, produced by current flow in the central cathode rather than the field produced by an external magnet. This self magnetic field is used to cut off electron flow to the anode. In present work, a MILO is selected for performance improvement with typical design parameters and beam parameters (beam voltage, beam current). Here, authors has designed the MILO for as 600 kV applied voltage and 35 kA beam current using simple structure with simple cathode, ladder cathode, complex structure, taper structure and by increasing the number of cavities with simple cathode in simple structure. Total design and analysis is based on PIC 2D Code "MAGIC" which is also verified with published results where, total RF output power is 1.05 GW and energy is 80 Joule for simple MILO, which is increased upto ~6-8 GW in total power and 180 Joule in energy after doing improvement. [ABSTRACT FROM AUTHOR]

This paper focuses on a differential voltage measurement in low-voltage automotive devices whose subunits are separated with a low-side safety switch. In contrast to conventional applications with high-side switches, a common-mode voltage (CMV) with negative polarity exists at the input of the signal conditioning circuitry. To overcome the shortage of dedicated integrated circuits capable of withstanding negative CMV, the paper investigates single- and two-stage differential circuits with single-supplied operational amplifiers to find a cost-optimized counterpart. In addition, the proposed procedure tunes the circuit parameters in such a manner to obtain the largest possible full-scale range at the output. Though, such optimization results in very uncommon values for gain and reference voltages. This issue is additionally evaluated for reference voltages that are either cost-effective or more easily accessible to increase the circuit feasibility. Since the impact of resistances on circuits' behaviour could be diminished to a great extent using high-precision and matched pair resistors, the sensitivity analysis was investigated only for a reference voltage change. Furthermore, a reversed termination of measured voltages results in a simplified reference voltage selection without hindering circuits' performance, proven by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Analysis of a gyrotron with symmetrically double-ridge structure shows that the growth rate and efficiency are high only when high-order mode is combined with high-order harmonic. The results illustrate that the ridge TE3013 gyrotron is effective at decreasing dc magnetic field B0, and has a growth rate of 10-2 level, a saturation efficiency of 51% and an output power of QPw = 1800 MW. [ABSTRACT FROM AUTHOR]

Thermal dissipation properties of metal core printed circuit boards (MCPCBs) with a dielectric layer having an anisotropically assembled microstructure are presented for dissipating heat of high-power transistors. The proposed MCPCB with an anisotropic microstructure was fabricated by applying an electric field simultaneously during the hot-pressing process. The effect of the anisotropically assembled microstructure of the dielectric layer compared with the conventionally fabricated dielectric layer was an increase in thermal diffusivity by the enhanced connectivity of fillers. Thermal transient measurements of high-power transistors with the proposed MCPCB were compared with those of high-power transistors with a conventional MCPCB. The developed MCPCB showed better heat dissipation performance and lower thermal resistance. [ABSTRACT FROM PUBLISHER]

We report state-of-the-art measured performance of class-B dual-gate GaAs power FETs fabricated using a highly manufacturable SAG technology. The class-B devices use selective co-implantation for FET channel formation and demonstrate 640 mW/mm (for 2.5 mm FETs) of power at C-band with 45% PAE and 11.4-dB gain. [ABSTRACT FROM AUTHOR]