Method and system of sensorless field orientation control for an AC motor

A field orientation control system for an AC motor, comprising:

• a current controller which performs control so that a high-frequency voltage of a constant magnitude may be inputted to the AC motor;
• and
• a field orientation controller which receives the output current from the AC motor, divides the output current from the AC motor into factors of an estimated flux axis and an axis orthogonal to the estimated flux axis, and determines the position and the speed of the actual flux axis by using the difference between the current factors on the estimated flux axis and the axis orthogonal to the estimated flux axis.

A field orientation control system for an AC motor, comprising:

• a current controller which performs control so that a high-frequency voltage of a constant magnitude may be inputted to the AC motor;
• and
• a field orientation controller which receives the output current of the AC motor, divides the output current from the AC motor into ids and iqs which are factors on two measurement flux axes in the stationary reference frame, divides the signal whose phase is different from the phase of the injected high-frequency voltage by π/2 into sds and sqs which are factors on two measurement flux axes in the stationary reference, obtains signal Q which is the difference between the product of sqs by ids and the product of sds by iqs, and determines the position and the speed of the flux axis from the signal Q.