Three phase induction motors employ a simple construction made up of a stator protected with electromagnets, and a rotor composed of conductors shorted at each end, arranged as a “squirrel cage”. 
They focus on the theory of induction where a rotating electro-magnetic field it created through the use of a three-phase current at the stators electromagnets. This in turn induces a current in the rotor’s conductors, which in turns produces rotor’s magnetic field that tries to follow stator’s magnetic field, pulling the rotor into rotation.
Benefits of AC Induction Motors are:
Induction motors are basic and rugged in building. They are more robust and can operate in any environmental condition
Induction motors are cheaper in expense because of simple rotor construction, lack of brushes, commutators, and slide rings
They are free of maintenance motors unlike dc motors because of the absence of brushes, commutators and slip rings
Induction motors can be operated in polluted and explosive conditions as they don’t have Induction in Motor brushes which can cause sparks
AC Induction motors are Asynchronous Machines and therefore the rotor does not change at the precise same speed because the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary to be able to create the induction in to the rotor. The difference between your two is named the slip. Slip should be kept in a optimal range in order for the motor to use efficiently. Roboteq AC Induction controllers can be configured to operate in another of three modes:
Scallar (or Volts per Hertz): an Open up loop mode where a command causes a simultaneous, fixed-ratio Frequency and Voltage change.
Controlled Slip: a Closed Loop speed where voltage and frequency are controlled in order to keep slip within a narrow range while working at a desired speed.
Field Oriented Control (Vector Drive): a Closed Loop Acceleration and Torque control that functions by optimizing the rotating field of the stator vs. this of the induced field in the rotor.
Find this video from Learning Engineering for a visual illustration on how AC Induction Motors are constructed and work.