Title：Simulation of three-phase induction motor variable frequency speed control system ABSTRACT Three-phase asynchronous motors are induction motors, the stator currents pass into the after part of the flux through the circuit loop, and in which the induced current. Short-circuit loop current impede flux changes, causing a short circuit ring-ring and no part of the magnetic flux generated with the phase, to form the rotating magnetic field. After power-up, the rotor winding and the magnetic field due to the relative motion exists between the induced electromotive force and current, that is, there is a relatively rotating magnetic field and the rotor speed, and with the magnetic interaction of the electromagnetic torque, the rotor turn up, to achieve energy conversion. In this paper, three-phase asynchronous motor frequency control is analyzed. This paper summarizes the history and development of frequency control summary to explain the classification and characteristics of the inverter; followed by analysis of the inverter power supply harmonics on motor performance, including the impact of the motor power factor and motor loss of influence; in based on the analysis of inverter-driven induction motor, the article concluded with induction motor variable frequency control system analysis.
KEY WORDS：Three-phase motor; frequency control; system simulation TYPE OF THESIS：Project Design
