sentences:  Field Oriented Control is a closed loop strategy composed of two current controllers (an inner loop and outer loop cascade design) necessary for controlling the torque, and one speed controller.Constant torque angle control
  
  In this control strategy the d axis current is kept zero, while the vector current is align with the q axis in order to maintain the torque angle equal with 90o.This is one of the most used control strategy because of the simplicity, by controlling only the Iqs current.