Patent ID: 7187152
Filing Date: 2007-03-06
Classification: G05B,H02P

Abstract:
1. An AC (alternating current) servo module without current sensor, comprising a servomotor and an AC servo drive connected to the AC servomotor, the AC servo drive comprising a PI (proportional integration) controller, at least two first-order controllers, a decoupling compensator, a coordinate converter, a pulse width modulator, a counter and a speed estimator to form an open-loop current circuit; wherein a built-in encoder in the servomotor receives a current command signal and produces feedback current signal for decoupling by program control, the feedback current signal and an angle speed feedback signal of the speed estimator form a decoupling current signal, the decoupling current signal and voltage command signals Vd, Vq of the first-order controller of d, q axes form a decoupled and compensated control signal to the coordinate converter, the decoupled and compensated control signal being converted to three-phase voltage command and processed by the pulse width modulator into a PWM (Pulse width modulation) signal and the PWM signal is sent to the servomotor to generate a rotational torque.