Analysis of the energy performance of an alternating-current drive under transient conditions

Abstract

The energy properties of an alternating-current drive are analyzed. The suggested method allows us to compare in an analytical form the energy quality indices of various drives under different means of electromagnetic- torque formation in an electrical machine. Using the relation between power and energy characteristics as functions of the energy state, the energy efficiency, and intensity of energy-conversion processes, as well as the usage efficiency of voltage and power applied to motor windings, are estimated. By means of the constructed relations between quality criteria, the developed method allows one to determine at the stage of design the main properties of an electric drive under static and dynamic conditions. Using energy-state functions and arguments based on means of electromagnetic-torque formation, the method allows us to determine the thermal state at selection or testing of an electrical machine on the basis of heating or overload conditions.