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Wenshan Li,Xuhui Wen,Jian Zhang,Youlong Wang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.6
This paper describes a narrow pulse suppression method that is called hybrid modulation strategy for T-type neutral point clamped (TNPC) three-level converters. Conventional VSVPWM does not function well in high-frequency TNPC converters due to the problem of narrow pulses during the permanent magnet synchronous motor (PMSM) starting process. The narrow pulse phenomenon occurs when the ON/OFF state time of the driving pulse is less than the minimum time required by the power devices. The narrow pulse threatens the safe operation of power devices and results in a high surge voltage and electromagnetic interference. In addition, neutral point voltage unbalance is caused by the narrow pulse in motor starting process. The eff ects of the narrow pulse on the surge voltage and the neutral point voltage are both discussed in this paper. The minimum pulse width function is designed to defi ne the relationship between the gate drive signal and the modulation strategy. The switch pattern limited region of the virtual space vector modulation strategy is analyzed by the minimum pulse width function under both low and high modulation indexes. A resistance inductance load and a PMSM drive system test setup based on a TNPC three-level converter are both established to verify the analysis and eff ectiveness of the proposed method.
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Review of Magnetic Coupling Resonance Wireless Energy Transmission
Bin Zhu,Jincheng Li,Wenshan Hu,Xingran Gao 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.3
This paper reviews the magnetic coupling resonance wireless energy transmission from the principle, models and theories based on the development and classification of wireless energy transmission technologies. Firstly, it introduces MIT coupled mode theory and the main circuit theory models and experiments, summarizes and illustrates the characteristics of the two theories. Secondly, it introduces the worldwide research progress in this area, including the circuit theories, three-coil energy transfer systems, multi-receptor, four-coil energy transfer systems, frequency tunable resonance body, adaptive tuning and frequency division, the loss distribution, new materials, mutual inductance coupling and frequency tracking. Finally combined with the main research content of magnetically coupled resonant wireless energy transmission, it points out the existing problems and the direction for the studies of the theory and application next step.
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