Introduction of asynchronous generators and synchronous generators
The difference between asynchronous generator and synchronous generator type:
They can be used for variable speed operation of the fan as long as the appropriate converter is used.
Asynchronous generators can be divided into different types according to their rotor structure:
(a) Cage asynchronous generator - the rotor is cage type. Because the structure is simple, reliable, cheap, and easy to access to the power grid, it is widely used in small and medium-sized units;
(b) Wire-wound doubly-fed asynchronous generator - the rotor is wire wound. The stator is directly connected to the grid to deliver electrical energy, and the wound rotor is also controlled by the frequency converter to deliver active or reactive power to the grid.
The type of synchronous generator type according to the magnetic pole that generates the rotating magnetic field can be further divided into:
(a) Electric Excitation Synchronous Generator - The rotor is a wire-wound salient pole that is excited by an external DC current to generate a magnetic field.
(b) Permanent magnet synchronous generator - The rotor is a permanent magnet pole made of ferrite material, usually low-speed multi-pole type, which does not require external excitation, which simplifies the structure of the generator and thus has various advantages.
