Improving the efficiency of a variable frequency asynchronous electric drive

Asynchronous electric drives hold leading positions in the global structure of electricity consumption. That's why the development and implementation of an energy-efficient asynchronous electric drive are always economically feasible and important. The aim of this article is to develop an algorithm to minimize losses of asynchronous electric drive power. The article offers methods to optimize the level of losses in the winding of an electric motor, powered in a steady-state mode by a frequency converter with a scalar control. The substitution scheme for an asynchronous electric drive is considered as a consistent set of conductivities for the stator and rotor wirings. The research tasks were solved based on theoretical and experimental methods, including mathematical and physical simulation of studied processes using modern measuring and computation devices as well as statistic treatment of experimental data. The article offers methods to minimize the losses of power in the winding of an electric motor, powered in a steady-state mode by a frequency converter with a scalar control. The offered method is significantly different in that it uses the substitution for an asynchronous electric drive expressed as a consistent set of conductivities for the stator and motor wirings and the use of the energy efficiency ratio which determines the losses of power in an asynchronous drive for assessing the efficiency of a drive. The main principle for optimal frequency control of an asynchronous engine in terms of energy efficiency was formulated. The laboratory bench for studying the modes of frequency-controlled electric drives was built. The tested drive AIR100S4 showed an increase in energy efficiency ratio from 0.59 to 0.67. (paper)