Stator Current Control Methods
The torque and speed of an induction motor can be controlled by the stator current the motor behaviour is different from that with VSI. A constant current for 3-? induction motor can be obtained from 3-? current source inverter but the use of CSI has the disadvantage that it generates the harmonics in the system. The circuit of stator current control methods for controlling the speed of induction motor is shown in figure.
Figure shown 3- phase controlled rectifier gives controlled dc voltage which converters into constant current by using inductor I current source inverter is used to emulate the output frequency and therefore speed of 3-? induction motor. Figure shown 3-phase uncontrolled rectifier gives uncontrolled dc voltage which is regulated by chopper and then it is converted to constant current by inductor then CSI controls the speed 3-phase induction motor.