Calculation of Electric Drives with Electric Machines of Unconventional Design

Abstract

The design procedure for electric drives operating in a zone of large overloads or having the motor with unconventional rotor design is presented. The calculation of the magnetic system is based on the finite-element method. In addition, the settings for the phase currents come from the control system. To reduce the time of calculation, an algorithm for parallelizing the calculations by the criterion of maximum acceleration was developed. A determination of the possibilities of design procedures depending on the number of processors and the nature of the problem to be solved is presented. It is shown that, if an electric drive has small overloads and they are in the tolerance zone, then it is more appropriate to give a preference to simplified design models and the parameters of an electric machine can be replaced by lumped ones. If an asynchronous electric drive operates with larger overloads (with an impact character of the torque of resistance or when frequent starting-brake operating modes with relatively large dynamic torque), it is appropriate to use refined design procedures. Electric drives with a complicated configuration of the magnetic system—for example, drives with a synchronous reluctance machine—require taking the distributed nature of the motor magnetic system into account. Moreover, there are electric-drive operating modes in the zone of large overloads by torque and with angles β < 30°, when higher demands are placed on the initial data of the design model.