Which is better, AC motor or DC motor?

AC motor and DC motor are the two main types of motors. It can be said that these two motors almost cover all types of motors. The so-called motor is a machine that can realize the mutual conversion between motor current and mechanical energy.
Which is better, AC motor or DC motor
1. First of all, the external power supply of the two is different. DC motor uses DC as power supply; while AC motor uses AC as power supply.
2. From the structural point of view, the principle of the former is relatively simple, but the structure is complex and not easy to maintain; while the principle of the latter is complex but the structure is relatively simple, and it is easier to maintain than DC motor.
3. The magnetic field of DC motor is stationary, and the conductor moves in the magnetic field; the magnetic field of AC motor rotates, and the conductor does not move.
4. In terms of speed regulation, DC motor can achieve smooth and economical speed regulation without the cooperation of other equipment. It can achieve speed regulation by changing the input or excitation voltage and current; while AC motor cannot complete speed regulation by itself, and needs to use
frequency conversion equipment to achieve speed change.
5. The motor structures are different. DC motors use direct current and do not directly generate a rotating magnetic field. They rely on a commutator that rotates with the rotor to change the direction of the current entering the rotor at any time, so that the polarity of the magnetic field between the rotor and the stator is always opposite, so that the rotor can rotate. AC motors use alternating current, so as long as the stator coils are arranged in phase, they will naturally generate a rotating magnetic field. (1) Structurally, the principle of DC motors is relatively simple, but the structure is complex and not easy to maintain. The principle of AC motors is complex but the structure is relatively simple, and it is easier to maintain than DC motors. (2) DC motors use brushes and commutators to introduce current into the rotor armature, so that the rotor is forced to rotate in the stator magnetic field. AC motors (taking the commonly used AC asynchronous motor as an example) pass alternating current into the stator winding, thereby generating a rotating magnetic field in the stator-rotor air gap. The rotating magnetic field generates an induced current in the rotor winding, which in turn causes the rotor to rotate in the stator magnetic field.