Owing to the advantages of high efficiency,high energy density,electrical isolation,low electromagnetic interference(EMI)and harmonic pollution,magnetic integration,wide output ranges,low voltage stress,and high opera...Owing to the advantages of high efficiency,high energy density,electrical isolation,low electromagnetic interference(EMI)and harmonic pollution,magnetic integration,wide output ranges,low voltage stress,and high operation frequency,the LLC resonant converters are widely used in various sectors of the electronics-based industries.The history and development of the LLC resonant converters are presented,their advantages are analyzed,three of the most popular LLC resonant converter topologies with detailed assessments of their strengths and drawbacks are elaborated.Furthermore,an important piece of research on the industrial applications of the LLC resonant converters is conducted,mainly including electric vehicle(EV)charging,photovoltaic systems,and light emitting diode(LED)lighting drivers and liquid crystal display(LCD)TV power supplies.Finally,the future evolution of the LLC resonant converter technology is discussed.展开更多
The analysis of the principle operation of the solar element is given in the work. The efficiency of the creation of combined high-efficiency converters of network energy in electric and thermal is indicated. A method...The analysis of the principle operation of the solar element is given in the work. The efficiency of the creation of combined high-efficiency converters of network energy in electric and thermal is indicated. A method for creating a combined photo thermo converter with a high value of the efficiency of a solar element has been found. A method for separating light from optical lenses is shown. The calculation of the light intensity into diffraction pattern is calculated using the Huygens-Fresnel principle. A new design of a highly efficient combined light-thermal converter into an electrical, with a solar element, operating on selective photoactive radiation is presented. The process of conversion of non-active radiation into electrical radiation by means of a thermo electronic converter is described. The ways of the solution of the problem connected with the reduction of the coefficient of its full effect as a function of temperature and characteristics are indicated.展开更多
In practical operations,low-frequency oscillation(LFO)occurs and leads to converter blocking when multiple electrical rail vehicles at the platform are powered by the traction network.This paper proposes a small-signa...In practical operations,low-frequency oscillation(LFO)occurs and leads to converter blocking when multiple electrical rail vehicles at the platform are powered by the traction network.This paper proposes a small-signal model in state-space form for multiple vehicle-grid systems based on a dynamic phasor.This model uses the phasor amplitude and phase as variables to accurately describe the dynamics of the converter phase-domain control.An eigenvalue based-method is introduced to investigate the LFO with advantages of acquiring all oscillatory modes and analyzing participation factors.Two low-frequency dominant modes are identified by eigenvalues.Mode shape reveals that one of the modes involves the oscillations between the grid-connected converters and the traction network,and the other one involves the oscillations among these converters.Then the sensitivities of these two low-frequency modes to different system parameters are analyzed.Participation factors of system state variables,when the number of connected vehicle increases,are compared.Finally,the theoretical analysis is verified by nonlinear time-domain simulations and the modal analysis based on the estimation of signal parameters via the rotational invariance techniques(ESPRIT)method.展开更多
基金Supported by the National Natural Science Foundation of China(51907032)the Natural Science Foundation of Guangdong Province(2018A030313365).
文摘Owing to the advantages of high efficiency,high energy density,electrical isolation,low electromagnetic interference(EMI)and harmonic pollution,magnetic integration,wide output ranges,low voltage stress,and high operation frequency,the LLC resonant converters are widely used in various sectors of the electronics-based industries.The history and development of the LLC resonant converters are presented,their advantages are analyzed,three of the most popular LLC resonant converter topologies with detailed assessments of their strengths and drawbacks are elaborated.Furthermore,an important piece of research on the industrial applications of the LLC resonant converters is conducted,mainly including electric vehicle(EV)charging,photovoltaic systems,and light emitting diode(LED)lighting drivers and liquid crystal display(LCD)TV power supplies.Finally,the future evolution of the LLC resonant converter technology is discussed.
文摘The analysis of the principle operation of the solar element is given in the work. The efficiency of the creation of combined high-efficiency converters of network energy in electric and thermal is indicated. A method for creating a combined photo thermo converter with a high value of the efficiency of a solar element has been found. A method for separating light from optical lenses is shown. The calculation of the light intensity into diffraction pattern is calculated using the Huygens-Fresnel principle. A new design of a highly efficient combined light-thermal converter into an electrical, with a solar element, operating on selective photoactive radiation is presented. The process of conversion of non-active radiation into electrical radiation by means of a thermo electronic converter is described. The ways of the solution of the problem connected with the reduction of the coefficient of its full effect as a function of temperature and characteristics are indicated.
基金This work was supported in part by the Fundamental Research Funds for the Central Universities of China(No.2682019CX20)in part by the Applied Basic Research Program of Science and Technology Plan Project of Sichuan Province of China(No.2020YJ0252)。
文摘In practical operations,low-frequency oscillation(LFO)occurs and leads to converter blocking when multiple electrical rail vehicles at the platform are powered by the traction network.This paper proposes a small-signal model in state-space form for multiple vehicle-grid systems based on a dynamic phasor.This model uses the phasor amplitude and phase as variables to accurately describe the dynamics of the converter phase-domain control.An eigenvalue based-method is introduced to investigate the LFO with advantages of acquiring all oscillatory modes and analyzing participation factors.Two low-frequency dominant modes are identified by eigenvalues.Mode shape reveals that one of the modes involves the oscillations between the grid-connected converters and the traction network,and the other one involves the oscillations among these converters.Then the sensitivities of these two low-frequency modes to different system parameters are analyzed.Participation factors of system state variables,when the number of connected vehicle increases,are compared.Finally,the theoretical analysis is verified by nonlinear time-domain simulations and the modal analysis based on the estimation of signal parameters via the rotational invariance techniques(ESPRIT)method.
