The principle of brushless excitation Was founded in 1950 by g to Aaron, calculate well, originally used in aviation motor.For the first time in 1960 the Westinghouse has been successfully used in brushless excitation on large steam turbine generator.In 1964 Japan Fuji company success developed brushless small diesel generator set.From the 60 s and 70 s, more than ten years' time, the fast development of brushless excitation systems.On the small synchronous generator, has occupied the absolute dominant position.Each industrial developed countries in the world, all have developed their ownBrushless synchronous generatorSeries.The main series has become a widely used in recent years.Brushless excitation is has been recognized as the most promising way of excitation.

As is known to all, synchronous generator excitation with a dc current.In the past he excitation synchronous generator, the dc current is supplied by the dc exciter near.Dc exciter is a kind of belt mechanical commutator rotating armature alternator, closed its polyphase armature winding cutting due to the magnetic field produced polyphase alternating current (ac), due to mechanical commutator and brush commutation of the rectifier system function, on the brush direct current (dc) are obtained.Through another brush and slip ring system will receive the dc current to the rotor of synchronous generator excitation winding excitation.So the commutator of the dc exciter in principle is a rectifier, obviously can be replaced with a group of silicon diode.The development of power semiconductor devices to provide the conditions.Semiconductor devices and the generator rotor consolidation in turn, can cancel the commutator, slip ring, such as sliding contact parts, using one-way conductive properties of the diode can be multiphase alternator armature current into direct current, directly to the rotor field winding excitation, this is the brushless excitation system.

Brushless excitationThe features are:

1, no sliding contact parts, simple maintenance and high reliability, can run continuously for a long time and don't maintain, especially suitable for unattended automation in power station:

2, no rotating contact conductive part, won't produce sparks, so there is particularly applicable to flammable gases and dust under the condition of bad environment such as operation situation;Due to belong to his excitation synchronous generator, so easy to achieve parallel operation;

3, rotating diode type brushless generator dynamic performance is poorer, rotating thyristor type dynamic characteristic is good, but the line is too complicated;

4, brushless generator compared with other self-excitation constant voltage generator. The volume is larger, the heavier weight, material consumption and more effectively;

4,Additional processing time has increased significantly.But compared with the dc exciter type synchronous generator, has quite a both.