Research On Three-stage Brushless Synchronous Generator Excitation Control

In recent years, with global demand for energy, changes in the structure and the improvement of environmental protection requirements, micro-gas turbine generator develops rapidly. The distributed energy represented by three-stage brushless micro-gas turbine generator is a new trend of energy application in the world. Excitation control system plays important part in the generator's safe and stable operation as an important supersystem. Advanced control theory has made the performance of excitation control system improve gradually.This thesis was written on the basis of 75KW micro-gas turbine generator excitation control system. Completed the design of excitation control system with phased rectifier main circuit, DSP control chip and H∞control theory.Based on the working principle of three-stage brushless generator, designed the overall program for the excitation control system, made a detailed analysis and comparison for the three commonly used rectifier main circuit, in view of the problem of Buck circuit with common-mode interference and loss, as well as the advantages of phased rectifier main circuit with fast response and small DC output voltage ripple value,finally completed the design of excitation control system with phased rectifier main circuit.Soluted the formation problem of phase-shift trigger pulse with combination of hardware circuitry and software flow chart, while hardware circuit including shaping circuit, pulse amplification circuit and software program including synchronous signal capture, frequency measurement, phase-shifted pulse and so on.Established the system model, calculated PID parameter with stability boundary method tuning formula, and given the corresponding simulation results:Its transient response time met the requirement, but had no ability to deal with the problem of external disturbances and system parameter perturbation.Designed H∞output feedback controller of three-stage brushless generator with parameter perturbations, external disturbances such issues, solved the problem of the H∞ standard design with application of linear matrix inequality. The simulation results of H∞control system showed that the H∞controller, which achieved good effects in the excitation control system.