Distinguishing between synchronous and asynchronous generators
The working principle of the generator is to convert mechanical energy into electrical energy. It is usually driven by a steam turbine, a water turbine or an internal combustion engine. The generator is divided into two major categories: DC generator and AC generator. The alternator can be divided into synchronous generator and asynchronous generator.
The most common use in modern power plants is synchronous generators. It is excited by DC current, which can provide both active power and reactive power to meet various load needs. The asynchronous generator does not have independent excitation windings, and has a simple structure and convenient operation, but cannot provide reactive power to the load.
For this reason, asynchronous alternators must be connected in parallel with other synchronous generators or connected to a considerable number of capacitors. The DC generator has a commutator, which has a complicated structure, is expensive, is prone to failure, is difficult to maintain, and is not as efficient as an alternator. Therefore, after the 1950s, the alternator was gradually replaced by a DC generator that was obtained by AC power rectification.
