FR-A701 INSTRUCTION MANUAL (Applied) - Automation Systems ...

Control mode(1) Speed controlSpeed control operation is performed to zero the difference between the speed command (ω*) and actual rotationdetection value (ωFB). At this time, the motor load is found and its result is transferred to the torque currentcontroller as a torque current command (iq*).(2) Torque current controlA voltage (Vq) is calculated to start a current (iq*) which is identical to the torque current command (iq) found bythe speed controller.(3) Magnetic flux controlThe magnetic flux (φ2) of the motor is derived from the excitation current (id). The excitation current command (id*)is calculated to use that motor magnetic flux (φ2) as a predetermined magnetic flux.(4) Excitation current controlA voltage (Vd) is calculated to start a current (id) which is identical to the excitation current command (id*) found bymagnetic flux control.(5) Output frequency calculationMotor slip (ωs) is calculated on the basis of the torque current value (iq) and magnetic flux (φ2). The outputfrequency (ω0) is found by adding that slip (ωs) to the feedback (ωFB) found by a feedback from the encoder.The above results are used to make PWM modulation and run the motor.74