AC servo drive without current sensor

An AC (alternating current) servo drive without current sensor, used in an AC servo module and performing vector control for a servomotor with decoupling function, the AC servo drive comprising:

• a servomotor comprising a built-in encoder;
• a PI (proportional integration) controller receiving a command signal formed by an angle speed command and a rotation feedback signal from a speed estimator and generates a torque current signal Iq* for feedback to q axis;
• at least two first-order controllers using current feedback signal generated by the servo module as input current command signal for d, q axes and generating output voltage command signals Vd, Vq;
• a decoupling compensator using current feedback signal generated by the servo module as feedback current for decoupling and providing an decoupled and compensated control signal with the output voltage command signals;
• a coordinate converter performing d, q coordinate conversion for the decoupled and compensated control signal;
• a pulse width modulator receiving the coordinate-converted signal for generating a PWM (Pulse width modulation) signal and then sending the PWM signal to the servomotor for generating a rotational torque;
• a counter connected to the encoder and outputting the angle speed measurement signal for using as trigging timing signal of the coordinate converter and the PWM controller and an input signal for the speed estimator;
• a speed estimator estimating rotation speed of the servomotor based on the angle speed measurement signal of the counter and outputting an angle feedback signal to the decoupling compensator and forming a command signal for the PI controller with an angle speed command signal of the servo module.

An AC (alternating current) servo drive without current sensor, used in an AC servo module and performing vector control for servomotor with decoupling function, the AC servo drive comprising:

• a servomotor comprising a built-in encoder;
• at least two first-order controllers using current feedback signal generated by the servo module as input current command signal for d, q axes and generating output voltage command signals;
• a decoupling compensator using current feedback signal generated by the servo module as feedback current for decoupling and providing an decoupled and compensated control signal with the output voltage command signals;
• a coordinate converter performing d, q coordinate conversion for the decoupled and compensated control signal;
• a pulse width modulator receiving the coordinate-converted signal for generating a PWM (Pulse width modulation) signal and then sending the PWM signal to the servomotor for generating a rotational torque;
• a counter connected to the encoder and outputting the angle speed measurement signal for using as trigging timing signal of the coordinate converter and the PWM controller and an input signal for the speed estimator;
• a speed estimator estimating rotation speed of the servomotor based on the angle speed measurement signal of the counter and outputting an angle feedback signal to the decoupling compensator and forming a command signal for the PI controller with an angle speed command signal of the servo module.