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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]

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]