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.
Preliminary investigation of an invertor-fed 5-phase induction motor
The paper reports some preliminary experiments on an invertor-fed 5-phase induction motor, and shows measured values of instantaneous current and torque. These are compared with the values predicted by a dual analogue. The amplitude of the torque fluctuation is approximately one third of that of the corresponding 3-phase motor.