The control speed of the AC servo motor is very accurate, and the voltage signal can be converted into torque and speed to drive the control object. The servo motor rotor speed is controlled by the input signal and can react quickly. It is used as an actuator in the automatic control system, and has the characteristics of small electromechanical time constant, high linearity, and starting voltage, which can receive the received electrical signal. Converted to an angular displacement or angular velocity output on the motor shaft.
With the features of the AC servo motor,we can make a analysis like below:
At present, there are two types of rotor structures that are widely used: one is a squirrel-cage rotor made of a high-resistivity conductive material made of a high-resistivity conductive material, and the rotor is made slender in order to reduce the moment of inertia of the rotor; One is a hollow cup rotor made of aluminum alloy with a thin wall. In order to reduce the magnetic resistance of the magnetic circuit, a fixed inner stator is placed in the hollow cup rotor. The hollow cup rotor has a small moment of inertia, rapid response, and stable operation, so it is widely used.
When there is no control voltage in the AC servo motor, only the pulsating magnetic field generated by the field winding is present in the stator, and the rotor is stationary. When there is a control voltage, a rotating magnetic field is generated in the stator, and the rotor rotates in the direction of the rotating magnetic field. When the load is constant, the rotational speed of the motor varies with the magnitude of the control voltage. When the phase of the control voltage is opposite, the servo motor Will reverse.
The configuration of the AC servo motor stator is basically similar to that of a capacitive split phase single-phase asynchronous motor. The stator is equipped with two windings with 90° difference between each other, one is the field winding Rf, which is always connected to the AC voltage UF; the other It is the control winding L, which is connected to the control signal voltage UC. Therefore, the AC servo motor is also called two servo motors.