The Investigation And Implementation Of Diesel Generators Excitation Control Systems Based On The Microcomputer

As an important main power or backup power supply, the diesel generators has been widely used in the fields of the communications, the military, the hospitals and so on.Digital excitation controller has high precision and fast dynamic response, which has been one of the effective means that can ensure the stable operation of diesel generator sets.In this thesis, the status and development of diesel generator sets and synchronous generator excitation control system is introduced at first. The structure, principle and features of synchronous generator excitation control system is analyzed.The key technology like main circuit connection mode, start excitation loop, short-circuit protection and reactive compensation and deexcitation of self-excitation excitation control system is researched. On the basis of that, a brushless excitation control programme based on chopper wave regulator is put forward. The main circuit of excitation control system and the structure of excitation controller based on dual-CPU architecture is designed. The working principle of chopper wave regulator is discussed. The main circuit design of excitation control system based on chopper wave controller is achieved.According to the dual-CPU architecture of the excitation controller, a hardware design project is put forward in this thesis. The right CPU is choiced. In order to achieve the communications between the MCU and DSP, the communications programme of dual-port RAM is discussed. The specific communications interface circuit is given. In accordance with the excitation control system functional requirements, the external interface circuit including the switch input and output circuit, CAN bus interface and analog input circuit is designed.In the final of the paper, the software design of the excitation control system is discussed. The data-sampling algorithm of the excitation control system is analysed. AC sampling technology that adopt the Fourier algorithm is introduced. And the concrete computer implement method is given. In order to carry out the excitation control, the fuzzy PID control algorithm is selected. The specific fuzzy controller is designed. Simulation results showed that PID control algorithm is better than that conventional PID control system in improving the dynamic and steady-state performance aspects of the generator system.