1960 years ago,Synchronous generator excitation system The excitation power unit, generally adopts dc exciter.Type excitation control unit adopts mechanical and electrical or electromagnetic type regulator.As the interconnection and the enlargement of capacity of power system, the excitation system has not up to the need of modern electric power system and large capacity units.Thereafter, the development of electronic technology has a semiconductor excitation system, the application of high power thyristor will ac excitation power supply for dc supply generator exciting winding, thus cancel the traditional dc exciter, the evolution of excitation system for the semiconductor.Actual operation experience for many years showed that semiconductors(At this stage mainly thyristor)Excitation system is the developing direction of excitation system.

Excitation regulator by electromechanical or electromagnetic development to analog integrated circuit regulator, until today Digital excitation regulator(AVR) gradually appear.On the synchronous generator at present a lot of use or analog regulator.But a generator capacity and power grid scale increasing, generators and power system of excitation controlIn rapidity, reliability, versatility, etc, put forward the higher request, analogue regulator（AVR）Is not up to the needs of the development of.Excitation control at the same time in the continuous development of practice and theory, and the application of computer technology and electronic technology, the replace the analog excitation regulator digital AVR, become the direction of development.