Research And Application Of Buck Converter In The Synchronous Generator Excitation Control System

Micro-turbine generator excitation system is not only the key issue which is the impact of China's technological development of micro-turbine power, but also one of the issues to be settled urgently which is the localization of micro-turbine power supply system.Buck converter technology is one of the main technical of a micro-turbine generator excitation system, through the Buck converter was well analysised and controlled, the entire system will works reliably and stably.Under this background, this thesis was written on the basis of micro-turbine excitation control system which was developed by Northeastern University and Shenyang Aerospace Xinguang Group. A Buck converter control system for the 75kW brushless synchronous generator excitation was designed in this thesis with the help of IGBT as power switch component and DSP as control chip, site debugging was completed, the results reached the design requirements.The main works of this thesis are shown as follows:(1) The entire scheme of hardware for the excitation control system was designed, including the rectifier, depressurization and filtration of the Buck converter. The sampling module, the frequency tracking module, the communication module, the PWM driver module were designed after well studing.(2) For the Situation of more serious noise environment, the electromagnetic compatibility of Buck convertor of the excitation control system had been analysised and improved, and the protection circuit was designed.(3) The auxiliary closed-loop control was increased based on the original excitation control system to control the output voltage of the Buck converter steadily which made the whole excitation control system running faster and steadier. In the modeling design of the Buck converter, the state space average method and fuzzy modeling method were employed. The simulation result proved that fuzzy modeling method was the optimum control method.(4) For the nonlinear response in the program, the T-S fuzzy control was used in the excitation system to design the fuzzy controller, then the results was simulated and compared to the results which was obtained by PID, it proved that the method in the thesis was valid.(5) Due to the more stability required in the system and the more complexity of the environment, the precise state parameter was difficult to acquire, as a result, the fuzzy observer was designed, further the observer and controller were united in the frame of LMI, then utilized the LMI tool in Matlab to get the parameter of the observer and controller, at last simulating the results to get the better effect than the general PID control method.