Showing papers by "Yongjian Li published in 2016"
TL;DR: In this article, an innovative dynamic wireless charging system based on magnetic coupled resonant power transmission is presented, where the structures of the transmitting coil and receiving coil are researched and improved.
Abstract: Wireless charging electric vehicles (EV) is the development trend of EV. However, the battery taken by EVs has the disadvantages of big volume, long time to recharge, and limited driving distance. In this paper, an innovative dynamic wireless charging system based on magnetic coupled resonant power transmission is presented. The transmitting coil of this charging system can selectively turn ON/OFF for charging vehicles while driving. The structures of the transmitting coil and receiving coil are researched and improved. In addition, the dispersed coupling structure named grouped periodic series spiral coupler is proposed, and its characteristics are described. A simulation of coupling coefficients at different $D$ values is carried out. A prototype is built to experiment on the dynamic wireless charging process of EV. Meanwhile, the coil coupling and variation of transmission efficiency are analyzed. The comparison of the experiment indicated that the EV can obtain a stable charging process under 25 mm transmission distance using the improved receiving coil with $R$ : $H$ : $D=4:5:13$ . Moreover, the dynamic charging process is relatively stable without an obvious fluctuation while passing the interval between two transmitting coils, and the transmission efficiency is promoted by 50%.
119 citations
TL;DR: In this paper, a 3D magnetic properties' testing method is proposed to measure the dynamic magnetic hysteresis properties of a laminated non-grain-oriented silicon steel sample.
Abstract: Magnetic properties of silicon steel laminations are important features in power transformer and electrical machine design and manufacture. Conventional testing methods such as Epstein Frame and Single Sheet Tester may only consider one direction or one sheet, which may deviate from the real application, particularly in core loss calculation. A 3-D magnetic properties' testing method is proposed in this paper. By using the designed special surface B-H sensing coils, the dynamic magnetic hysteresis properties of a laminated non-grain-oriented silicon steel sample are accurately measured. The relationship between B and H in alternating, 2-D rotational, and 3-D spherical rotational excitations, from 50 to 200 Hz, is studied and analyzed. In order to control the B waveform better, the harmonics of B
x
and B
y
signals are analyzed at 50 Hz. The alternating core losses in the rolling, transverse, and laminated directions and the rotational core losses in the xoy plane of this sample at 50, 100, and 200 Hz are calculated and analyzed. Moreover, the core losses in the three directions are well predicted by means of total core loss separation theory.
9 citations
TL;DR: In this paper, a calculation model of anomalous loss in magnetic materials is built on the basis of the production and domain wall motion and a macrophysical interpretation of this model is described in detail, and a testing method to determine the microstatistical characteristic parameters is proposed due to the pure anomalous losses obtained by the separation of total experimental core losses in electrical steel sheets.
Abstract: By using statistical approaches, a calculation model of anomalous loss in magnetic materials is built on the basis of the production of anomalous loss and domain wall motion. Based on that, a macrophysical interpretation of this model is described in detail, and a testing method to determine the microstatistical characteristic parameters is proposed due to the pure anomalous loss obtained by the separation of total experimental core losses in electrical steel sheets. Meanwhile, the characteristics of the coefficient of anomalous loss are analyzed. In addition, rotating anomalous loss can be extended in this model. Therefore, under trusted error range, the separated and predicted values of alternating and three-dimensional rotating anomalous losses are compared and analyzed, respectively. The results clearly underline the necessity of achieving more accurate loss coefficients.
9 citations
TL;DR: In this paper, a new method of three-dimensional magnetic properties measurement is used for complex magnetic properties of the laminated silicon steels, which can provide dynamic and comprehensive data to design and evaluate performance of electrical machines and power transformers.
Abstract: Comprehensive magnetic properties of the laminated silicon steels are key factors in magnetic core design, which should be measured and modeled by using a new testing method. Comparing with traditional Epstein frame and single sheet tester, a new method of three-dimensional magnetic properties measurement is used for complex magnetic properties of the laminated silicon steels. The comparison of magnetizations between the rolling or transverse direction and the laminated direction are illustrated. Both magnetic hysteresis and core loss features of the silicon steels specimen are measured and analyzed considering the laminated direction. The hysteresis loss, classical eddy current loss, and excess loss are analyzed and compared in different directions. This study can provide dynamic and comprehensive data to design and evaluate performance of electrical machines and power transformers.
9 citations
TL;DR: In this paper, the effects of the eddy currents in the permanent magnet during the magnetizing process on residual flux distribution have been also analyzed, and the effectiveness of the T-Ω method used in the magnetization process of permanent magnets was certified by a comparison between the calculated average magnetization ratios and the measured ones.
Abstract: When analyzing magnetic field distribution of the permanent magnets during the magnetizing process, it is important to couple the system equations of analysis method to the equation for the electric circuit. In this paper, the equations to calculate the residual flux distribution of permanent magnets using the T-Ω method taking into account the magnetizing process that uses the discharge current of a capacitor were developed. The effects of the eddy currents in the permanent magnet during the magnetizing process on residual flux distribution have been also analyzed. These calculated results are very useful for obtaining the optimum conditions for the magnetizing process. The effectiveness of the T-Ω method used in the magnetizing process of permanent magnets was certified by a comparison between the calculated average magnetization ratios and the measured ones.
1 citations
01 Nov 2016
TL;DR: In this paper, a finite element method considering the micro eddy current is proposed, and the algorithm is discretized and implemented by Matlab, in order to verify the algorithm, a magnetic ring of nanocrystalline soft magnetic is measured at 50k Hz and 100 kHz.
Abstract: The eddy current effect of laminated steel is significant to the design of high frequency transformer(10 kHz–100 kHz). In this paper, the finite element method considering the micro eddy current is proposed. And, the algorithm is discretized and implemented by Matlab. In order to verify the algorithm, a magnetic ring of nanocrystalline soft magnetic is measured at 50k Hz and 100 kHz. The simulation results prove the validity of the proposed algorithm.