1. Overview of AC motor
Ac motor is used to realize the conversion of mechanical energy and AC electric energy.
Due to the great development of AC power systems, AC motors have become the most commonly used motor. Ac motor compared with DC motor, because there is no commutator (see commutation of DC motor), so the structure is simple, easy to manufacture, more firm, easy to make high speed, high voltage, large current, large capacity motor. Ac motor power covers a large range, from a few watts to hundreds of thousands of kilowatts, or even millions of kilowatts. In the early 1980s, the largest turbogenerator had reached 1.5 million kilowatts.
The AC motor uses the magnetic field generated by the AC power supply to act on the annular current in the rotor, thus generating torque; The DC motor generates a fixed magnetic field through a magnet or electromagnet, and then generates a rotating magnetic field on the stator by the current to drive the rotor to rotate. Therefore, the AC motor controller needs to adjust the voltage and frequency to change the motor speed and torque, while the DC motor controller needs to adjust the current to change the speed and torque.
2. Performance characteristics of AC motor controller and DC motor controller
Ac motor controller and DC motor controller also have a big difference in performance characteristics. Ac motor controller has the characteristics of high efficiency and low noise, but electromagnetic noise and torque fluctuation will occur at low speed. The DC motor controller has the characteristics of fast response, high precision and smooth operation, but the power density is low and the volume is larger.
