Model for simulation of dynamic characteristics of the system frequency converter − AC induction motor

Model of system frequency converter – induction motor and its dynamic characteristics is analyzed. The model of variable – frequency electric drive in PSpice is elaborated. Three phase induction motor is modelled as equivalent two-phase motor in stationary reference frame. Frequency converter is modelled by replacement it by two voltage sources, used to supply phase windings of equivalent two – phase motor. Results of simulation: starting transients of current, speed and torque of motor at no load are presented and analysed. In the motor, supplied by frequency converter, active communicating processes in the windings cause pulsations of electromagnetic torque of high amplitude, what do not decay even after transient time is over. Analysis of speed starting transients shows, that in the motor, supplied by frequency converter, they 20% longer, than at three-phase supply