Efficiency invariance laws and development of multiphase AC inverter drives

The study of AC inverter drives in the case when the number of their phases is more than four allows to find 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. These laws ignoring leads necessarily to the decrease of the multiphase drive system energy efficiency.