Difference between synchronous generator and asynchronous generator

Generators are divided into two types: synchronous and asynchronous generators. When the load power factor is relatively low, the capacitor in the external circuit can play a role in reactive power compensation, improve the power factor and reduce the circuit current.

Synchronous generator is a synchronous motor that works as a generator. It is the most commonly used AC generator. It is widely used in hydropower, thermal power, nuclear power and diesel power generation. The structure of synchronous generator is divided into high speed and low (medium) speed according to its speed. The former is mostly used in thermal power plants and nuclear power plants; the latter is mostly linked with low-speed turbines or diesel engines. In terms of structure, high-speed synchronous generators mostly use hidden pole rotors, while low (medium) speed synchronous generators mostly use salient pole rotors.

An asynchronous generator is an AC generator that uses the interaction between the rotating magnetic field in the air gap between the stator and the rotor and the induced current in the rotor winding. An asynchronous generator is also called an "induction generator". An AC generator that uses the interaction between the rotating magnetic field in the air gap between the stator and the rotor and the induced current in the rotor winding. The direction of rotation of its rotor is the same as that of the rotating magnetic field, but the speed is slightly higher than the synchronous rotation of the rotating magnetic field.

The differences between synchronous generators and asynchronous generators are as follows:

1. Different working principles: Synchronous generators generate electricity by running synchronously with the power grid, while asynchronous generators generate electricity by creating a rotating magnetic field between the rotor and stator.

2. Different speed control methods: The speed of the synchronous generator is fixed, equal to the frequency of the power grid, and the output power is adjusted by controlling the power factor; while the speed of the asynchronous generator can be adjusted, which is controlled by changing the additional impedance or changing the rotor current.

3. Different starting methods: Synchronous generators must be started with the help of the power grid, while asynchronous generators can be started by a short external starter.

4. Different operating stability: Synchronous generators are relatively stable during operation and have higher efficiency and power factor; while asynchronous generators are prone to lose synchronization when the load fluctuates greatly, resulting in unstable output power and power factor.

5. Different application areas: Synchronous generators are usually used in large power grids and power systems with high power requirements, such as power stations and power plants; while asynchronous generators are more suitable for small micro-generator sets and industrial applications, such as steel, cement, metallurgy and other industries.