Быстроходные электромеханические преобразователи энергии: оптимизация геометрии активной зоны ротора на основе требований механической прочности

Abstract

AC machines with the nominal rotation frequency higher than 3000 rpm find increasingly growing use. These machines are made with bulky rotors for ensuring mechanical strength, and the slots in them are made with a rectangular shape, usually with a wedge (for retention of the field winding or permanent magnets, or short-circuited winding bars), or with a trapezoid shape. An investigation of the bulky rotor tooth zone design has shown that, given a specified stress at the tooth base, the maximal area of rotor slots with their optimal height can be obtained. In this way, the maximum MMF of the rotor (at the specified current density) and, hence, the maximum value of the machine nominal power are achieved. In the article, the problem of determining the optimal tooth zone geometry in a bulky rotor is solved for the general case of using a trapezoid slot with any ratio of the slot widths at the base and under the wedge, and with any value of the averaged specific mass. The problem has been solved for arbitrary runaway rotation frequency (n≥3600 rpm). An example of optimizing the rotor tooth zone is given.