A new hybrid model rotor flux observer, based on a new voltage model, is presented. In the first place, the voltage model of an induction machine was constructed by using the modeling method discussed in this paper an...A new hybrid model rotor flux observer, based on a new voltage model, is presented. In the first place, the voltage model of an induction machine was constructed by using the modeling method discussed in this paper and then the current model using a flux feedback was adopted in this flux observer. Secondly, the two models were com- bined via a filter and then the rotor flux observer was established. In the M-T synchronous coordinate, the observer was analyzed theoretically and several important functions were derived. A comparison between the observer and the traditional models was made using Matlab software. The simulation results show that the observer model had a better performance than the traditional model.展开更多
The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using po...The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using power converters they can be strongly non-harmonic, sometimes piecewise constants with zero spaces between them. Then, one deals with power series of time pulses. The impulse switching functions which are orthogonal ones can be derived from these series. The new impulse switching functions are created using Z-transform, inverse Z-transform and numerical series/sequences. The impulse switching functions created this way can be used for both steady- and transient state investigation of converters.展开更多
This paper presents an experimental investigation of the influence of a transversal flow deflector on the cooling of a heated block mounted on a flat plate.The deflector is inclined and therefore it guides the air flo...This paper presents an experimental investigation of the influence of a transversal flow deflector on the cooling of a heated block mounted on a flat plate.The deflector is inclined and therefore it guides the air flow to the upper surface of the block.This configuration is simulating the air-cooling of a rectangular integrated circuit or a current converter mounted on an electronic card.The electronic component is assumed dissipating low heat power,as such,air forced convection is still a sufficient cooling way even without fan or heat sink on the component.The measurements are given by hot and cold wires anemometers and by an InfraRed camera.The results give details of the effects of the deflection on the hydrodynamic and the thermal fields on and over the block for different inclination angles.They show that the deviation caused by the deflector may significantly enhance the heat transfer from the component.Deflection is also able to avoid local overheating of the electronic component.Optimum heat transfer rate and homogenised temperature are shown to be obtained with an inclination angle =30°.展开更多
基金Projects (00KJD470002, 03KJD470036) supported by the Natural Science Foundation of the Bureau of Education Jiangsu Province
文摘A new hybrid model rotor flux observer, based on a new voltage model, is presented. In the first place, the voltage model of an induction machine was constructed by using the modeling method discussed in this paper and then the current model using a flux feedback was adopted in this flux observer. Secondly, the two models were com- bined via a filter and then the rotor flux observer was established. In the M-T synchronous coordinate, the observer was analyzed theoretically and several important functions were derived. A comparison between the observer and the traditional models was made using Matlab software. The simulation results show that the observer model had a better performance than the traditional model.
文摘The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using power converters they can be strongly non-harmonic, sometimes piecewise constants with zero spaces between them. Then, one deals with power series of time pulses. The impulse switching functions which are orthogonal ones can be derived from these series. The new impulse switching functions are created using Z-transform, inverse Z-transform and numerical series/sequences. The impulse switching functions created this way can be used for both steady- and transient state investigation of converters.
基金support of the Comité Mixte Franco-Tunisien pour la Coopération Universitaire(ProjectCMCU 08G1131)
文摘This paper presents an experimental investigation of the influence of a transversal flow deflector on the cooling of a heated block mounted on a flat plate.The deflector is inclined and therefore it guides the air flow to the upper surface of the block.This configuration is simulating the air-cooling of a rectangular integrated circuit or a current converter mounted on an electronic card.The electronic component is assumed dissipating low heat power,as such,air forced convection is still a sufficient cooling way even without fan or heat sink on the component.The measurements are given by hot and cold wires anemometers and by an InfraRed camera.The results give details of the effects of the deflection on the hydrodynamic and the thermal fields on and over the block for different inclination angles.They show that the deviation caused by the deflector may significantly enhance the heat transfer from the component.Deflection is also able to avoid local overheating of the electronic component.Optimum heat transfer rate and homogenised temperature are shown to be obtained with an inclination angle =30°.
