Difference between Synchronous Generator and Asynchronous Generator

by Starlight Generator dieselgeneratortech

Synchronous generator, that is, an alternator with the same rotor speed as the rotating magnetic field of the stator. According to the structure, it can be divided into two types: a rotating armature and a rotating magnetic field.

Synchronous generators are one of the most commonly used alternators. In the modern power industry, it is widely used in hydropower, thermal power, nuclear power generation and diesel power generation.A synchronous motor that operates as a generator is one of the most commonly used alternators. In the modern power industry, it is widely used in hydropower, thermal power, nuclear power generation and diesel engine.

Electricity. Since the synchronous generator generally adopts DC excitation, when the single machine operates independently, the voltage of the generator can be conveniently adjusted by adjusting the excitation current. If it is integrated into the grid operation, the voltage is determined by the grid and cannot be changed. At this time, the result of adjusting the excitation current is to adjust the power factor and reactive power of the motor.

An asynchronous generator is an alternator that utilizes an air gap rotating magnetic field between a stator and a rotor to interact with an induced current in a rotor winding. According to the working principle, it is also called "induction generator". The speed is slightly higher than the synchronous speed. The output power increases or decreases with the slip rate. It can be excited by the power grid or self-excited with a power capacitor.

Economical efficiency

(1) The power station equipped with asynchronous generators has low investment cost due to the lack of DC excitation system and synchronous devices.

(2) Since there is no collector ring, brush, and rotor excitation winding, maintenance and operation costs are low.

(3) The asynchronous generator rotor is a rotor winding similar to the hidden pole and the non-synchronous generator. Therefore, the general efficiency is higher than that of the synchronous generator with the same capacity and the same speed. Under the same water source, the asynchronous generator can generate more power.

(4) The above economic advantages of asynchronous generators will be partially offset by the required excitation (or additional synchronous capacity or additional capacitors) of the asynchronous generator.

(5) The magnitude of the excitation required for the asynchronous generator is inversely proportional to the rated speed of the motor (ie, proportional to the number of pole pairs of the motor). The higher the speed, the lower the excitation of the target value.

(6) The area of the asynchronous generator power plant is smaller than that of the synchronous generator power plant