AC Excitation Control Of Coordinate Structure Hybrid Excitation Synchronous Generator

The permanent-magnet synchronous machine (PMSM) regulates the magnetic field difficultly. And it exist a disadvantage of high voltage regulation ratio when its load increases and temperature rises. In order to improve the regulation difficulty of the magnetic field and the voltage of PMSM, a coordinate structure hybrid excitation synchronous generator (HESG) with AC excitation is proposed in this thesis. The thesis mainly focuses on the mathematical model of HESG, the characteristic simulation and vector control method of AC excitation.Firstly, a brushless coordinate structure HESG with AC excitation is proposed. The structure and operation principle of the HESG are described. The electrical excitation part of HESG adopts brushless AC excitation. Since there is no additional air-gap in the magnetic circuit, the HESG has high electrical excitation efficiency and well environment adaptability.Secondly, the mathematical model of coordinate structure HESG is built. Based on the state equation of HESG, the simulation model of the HESG is established with S-function. Then the no-load characteristic, external behaviors and the regulation characteristic are simulated. The output voltage of the generator can be adjusted by regulating the amplitude and phase of the AC excitation current. Then, the vector control method is used to control AC excitation current. With the double feedback loop including excitation current inner-loop and voltage outer-loop, the vector control method implements the stabilized output voltage control of HESG. The simulation results verify the feasibility of the proposed HESG and the correctness of the mathematical model.Finally, the hardware circuit of AC excitation vector control system based on TMS320F2812is designed. The circuit includes DSP control module, excitation current driver module and generator rotor position detecting module.