Energy Efficiency Invariance Laws Acting in the Field of Multiphase Inverter-Fed AC Linear Motors
The study of AC inverter liner and non-linear drives in the case when the number of their phases is more then four allows finding out some basic laws of these systems which does not manifest themselves when the phase number is equal to three or four. Two previously unknown laws of energy efficiency invariance are established in the field of multiphase (i.e. having the number of phases more than four) AC inverter drives. The ignoring these laws lead necessarily to the decrease of the multiphase drive system energy efficiency.
Over-phase control of inverter multiphase AC linear drives
Abstract The over-phase control method of inverter multiphase (i.e. having number of phases more than four) AC linear drives is developed by the authors of this paper. Its application allows to improve considerably a number of the drive technical-and-economic characteristics (speed of response, reliability, mass-and-overall dimensions, etc.). This control method can be used not only in the field of electrical AC drives, but also in the systems for electromagnetic stirring of molten metals. In these systems the application of one of versions of the over-phase-control for multiphase inverter-fed linear stators allows to increase the intensity of electromagnetic stirring of molten metals by providing with continuous change of the quantity, space location, and configuration of the vortex areas in the metal mass during the process of the above-mentioned stirring.
Contribution à l'étude de la machine asynchrone double étoile : modélisation, alimentation et structure
Les machines multiphasees sont de plus en plus utilisees pour des raisons de fiabilite et de segmentation de puissance. Nous nous proposons d'en etudier un exemple, la machine asynchrone double etoile. L'etude s'articule autour d'un phenomene nefaste important, celui de l'apparition de courants de circulation statoriques lors d'une alimentation par onduleurs de tension. La modelisation nous permet tout d'abord d'expliquer precisement l'origine de ces courants afin de rechercher des solutions permettant de minimiser leur amplitude. L'alimentation en modulation de largeur d'impulsions est ensuite abordee et une nouvelle technique de modulation vectorielle, dans sa version continue et discontinue, est developpee. Nous nous interessons enfin a des solutions structurelles, par une etude approfondie des inductances de fuite statoriques, et proposons des configurations de bobinage appropriees. Cette etude est validee experimentalement sur un prototype de machine realisee pendant de la these.