Зависимость момента и токов в асинхронном двигателе при частотно-токовом управлении от соотношения параметров двигателя и управляющих сигналов

Abstract

The static adjustment characteristic of a servo drive’s power part equipped with a frequency- and current-controlled induction motor (IM) is analytically studied. All the analytical dependences are given in relative units. A practically important formula for the induction motor torque and stator current components as functions of the active and reactive current reference signals is obtained. The forms of calculated adjustment characteristics for different deviations of the reference signals from their desired ratios ensuring a linear dependence between the torque and reference signal are given. It is shown that a linear dependence between the IM torque and the control signal UQ can only be obtained at a certain rotor current variation frequency reference gain Кw= Кwlin , and it is shown how to control the electric drive proceeding from the pattern (convex or concave) of the characteristic M f U IM Q = ( ). In addition, analytical dependences for an IM with any number of pole pairs р are considered, and the parameter variation ranges within which the no-load characteristic’s nonlinearity due to saturation of the induction motor magnetic circuit may not be considered are indicated.