what is id and iq in electric motor terms?
In AC motors, say induction motor, the stator field is rotating at synchronous speed, and induces rotating currents in the rotor, at a little less than synchronous speed. To study these currents one needs to know how the magnitude varies as well as the angle with respect to some reference. Because these are time-varying currents, it is helpful to choose a rotating frame of reference - a pair of axes called d and q at an arbitrary position on the stator rotating field. All currents can be referred to this reference frame, and would appear stationary (duh! you are rotating at synchronous speed - everything looks stationary). These currents are referred to as id and iq.
