VARIABLE FREQUENCY SPEED CONTROL SYSTEM FOR MOTOR

摘要

The present invention relates to a frequency conversion and speed regulation system of electric motor, comprising a electric motor, the electric motor including a first stator winding having the pole pair number G of a first winding for connecting to a high-voltage AC power supply; a second stator winding having the pole pair number D of a second winding; a rotor winding; a frequency conversion and speed regulation device, comprising: a rectifying unit, its input end being connected to the low-voltage AC power supply; a inverting unit, its input ends being connected to the output end of the rectifying unit, its output end being connected to the second stator winding; a first current detecting unit for detecting a three-phase current of the first stator winding; a second current detecting unit for detecting a three-phase current of the second stator winding; a controller, its input ends being connected to the first current detecting unit and the second current detecting unit, its output ends being connected to the input ends of the inverting unit. With this technical solution, a high-voltage large power electric motor can be controlled by using a frequency conversion and speed regulation device with the low-voltage small power.