An induction electric motor or asynchronous motor can be an AC electric electric motor in which the electric current in the rotor needed to create torque is obtained by electromagnetic induction from the magnetic field of the stator winding. … An induction motor’s rotor can be either wound type or squirrel-cage type.
Great things about AC Induction Motors are:
Induction motors are simple and rugged in structure. They are better quality and can operate in any environmental condition
Induction motors are cheaper in cost because of simple rotor construction, absence of brushes, commutators, and slip 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 environments as they don’t have brushes which can cause sparks
AC Induction motors are Asynchronous Devices and therefore the rotor does not turn at the precise same speed as the stator’s rotating magnetic field. Some difference in the rotor and stator speed is necessary to be able to create the induction 
into the rotor. The difference between the two is named the slip. Slip should be kept within an optimal range in order for the motor to use effectively. Roboteq AC Induction controllers could be configured to operate in another of three modes:
Scallar (or Volts per Hertz): an Open loop mode in which a order causes a simultaneous, fixed-ratio Frequency and Voltage alter.
ac motor Controlled Slip: a Shut Loop speed where voltage and frequency are controlled in order to keep slip inside a narrow range while working at a desired speed.
Field Oriented Control (Vector Drive): a Closed Loop Swiftness and Torque control that functions by optimizing the rotating field of the stator vs. this of the induced field in the rotor.
See this video from Learning Engineering for a visual illustration about how AC Induction Motors are constructed and work.