Research On AC-excited Control System For High-head Impulse Turbine Generator Set

It is of great significance to develop and utilize water power,which is not only renewable but also without pollution when energy source scarcity and environment pollution are getting more and more serious.Water power generation technique is improved greatly thanks to that more and more countries all over the world pay attention to it.With the increasing scale of water power generation system,the research on water power generation technique has been focused on improving the operation efficiency of water power generation.This paper sets the operation and control of AC excitation VSCF control system for high-head impulse turbine generator as the research subject, it makes an in-depth study from theory to simulation.First, this dissertation analyzes the operation theory of AC excitation VSCF, including mathematic model of DFIG,coordinate transformation,DFIG operation characteristics and adopting vector control way with stator flux oriented,which establishes the theoretical foundation of succeeding study.The second, based on the introduction of the high-head impulse turbine operation characteristics, the optimal speed curve was educed, and the max efficiency capture scheme by the way of DFIG power control was put forward. Third, based on the analysis of existent techniques of water generator grid connection, this dissertation discusses the grid-connection control principle which fits for the occasion of the high-head impulse generator set, and control schemes which can be called grid-connection control with no-load was put forward. At the same time, the flux linkage and phase observer were designed. The every partial and general simulation model in Matlab/Simulink are made and the simulation results show the control schemes achieve grid-connection control with no-load.Finally, the calculation method of the reference power of DFIG was discussed in detail, and build the calculate models of voltage reward and the signal of rotor voltage. In order to realize decoupled control of DFIG active & reactive power and to capture the max efficiency,field oriented vector control technique was applied to DFIG control. A general control strategy based on stator flux oriented vector control was proposed as well. The every partial and general simulation model in Matlab/Simulink are made and the simulation results show the control schemes can the adjust active & reactive power of electricity meshwork independently.