A contactless slipring (CS) system utilizing inductive-power-transfer (IPT) technology is a good candidate for traditional mechanical slipring assemblies. However, suffering from the high harmonic currents in strong c...A contactless slipring (CS) system utilizing inductive-power-transfer (IPT) technology is a good candidate for traditional mechanical slipring assemblies. However, suffering from the high harmonic currents in strong coupling CS systems, the output power will deviate from the theoretical values estimated by the fundamental harmonic approximation (FHA) and its extension method, i.e., E-FHA, in which the power is transferred by both the fundamental current and the high order harmonic currents. In order to achieve high precise output estimation, a unified analysis is proposed in this paper. First, “Fundamental-harmonic Double Resonance Phenomenon” is revealed via impedance analysis, to address the nature of the high harmonic currents in strong coupling systems. Then, a unified output current expression owning high precision is derived, and followed by a unified fundamental load impedance. Discussions show that both the output and the fundamental load impedance of FHA, and E-FHA are the special cases of the unified expressions proposed. FHA and E-FHA are precise enough for the loose coupling system, whereas the proposed method is indispensable for the strong coupling system with k>0.4 . Finally, simulations and experimental measurements of a 1.6kW CS system, as well as the comparative studies related to FHA, E-FHA, and the proposed method, are presented, indicating that the proposed method is effective for high precise output estimation.展开更多
Emerging wide-bandgap(WBG)devices,such as silicon carbide(SiC)MOSFETs and gallium nitride(GaN)high-electron-mobility transistors(HEMTs)provide new opportunities to realize high efficiency,high power density,and high r...Emerging wide-bandgap(WBG)devices,such as silicon carbide(SiC)MOSFETs and gallium nitride(GaN)high-electron-mobility transistors(HEMTs)provide new opportunities to realize high efficiency,high power density,and high reliability in several kHz,1 kV input,and several kW output applications.However,the performance comparison between SiC MOSFETs and GaN HEMTs in high-voltage,high-frequency,medium-high-power DC conversion applications have not yet been investigated thoroughly.Two 1 kV,3 kW LLC prototypes with GaN and SiC devices are built to perform a careful comparison of the prototypes in terms of parameters,power density,zero voltage switch realization,and overall efficiency.This provides guidance for the appropriate evaluation of WBG devices in high-voltage,high-frequency,and medium-high-power applications.展开更多
基金the National Natural Science Foundation of China under Grants 51677086 and 51777093.
文摘A contactless slipring (CS) system utilizing inductive-power-transfer (IPT) technology is a good candidate for traditional mechanical slipring assemblies. However, suffering from the high harmonic currents in strong coupling CS systems, the output power will deviate from the theoretical values estimated by the fundamental harmonic approximation (FHA) and its extension method, i.e., E-FHA, in which the power is transferred by both the fundamental current and the high order harmonic currents. In order to achieve high precise output estimation, a unified analysis is proposed in this paper. First, “Fundamental-harmonic Double Resonance Phenomenon” is revealed via impedance analysis, to address the nature of the high harmonic currents in strong coupling systems. Then, a unified output current expression owning high precision is derived, and followed by a unified fundamental load impedance. Discussions show that both the output and the fundamental load impedance of FHA, and E-FHA are the special cases of the unified expressions proposed. FHA and E-FHA are precise enough for the loose coupling system, whereas the proposed method is indispensable for the strong coupling system with k>0.4 . Finally, simulations and experimental measurements of a 1.6kW CS system, as well as the comparative studies related to FHA, E-FHA, and the proposed method, are presented, indicating that the proposed method is effective for high precise output estimation.
基金Supported by Industrial Prospective and Key Core Technology Funding of Jiangsu Province(BE2019113).
文摘Emerging wide-bandgap(WBG)devices,such as silicon carbide(SiC)MOSFETs and gallium nitride(GaN)high-electron-mobility transistors(HEMTs)provide new opportunities to realize high efficiency,high power density,and high reliability in several kHz,1 kV input,and several kW output applications.However,the performance comparison between SiC MOSFETs and GaN HEMTs in high-voltage,high-frequency,medium-high-power DC conversion applications have not yet been investigated thoroughly.Two 1 kV,3 kW LLC prototypes with GaN and SiC devices are built to perform a careful comparison of the prototypes in terms of parameters,power density,zero voltage switch realization,and overall efficiency.This provides guidance for the appropriate evaluation of WBG devices in high-voltage,high-frequency,and medium-high-power applications.
