Design And Research Of PWM Converter VSCF Of Doubly-fed Generator

Recently, energy sources consuming increasing continuously and environmentempoison being serious gradually, force people to consider new and renewableenergy development and utilization, Due to its obvious advantages, wind power hasattracted the becomes research hotspot of scholars all over the world. The wingpower generation system with variable-speed constant-frequency (VSCF) cancapture energy as much as possible. In this kind of system, the control and design ofthe AC-excited power supply are of great importance. This thesis deals with thecontrol of the dual PWM converter which is used in doubly-fed wind-powergeneration system.At first, this paper analyzes the fundamental principles of the dual PWMconverter VSCF excitation of wind power generation system , Discussed the functionand control method of PWM converter in the rotor side . Proposed the controlstrategy based on stator flux oriented vector through the research of themathematical model of DFIG in three-phase stationary coordinate system and thetwo-phase rotating coordinate system. In this paper, the stator voltage model fluxobserver is analyzed , proposed the method of stator flux observer by combine theintegral and low-pass filter. Authenticate its feasibility by Matlab/simulink.Secondly, in order to achieve the AC side unity power factor control and DCbus voltage control of the network-side PWM converter, this paper analyzes itstopology and mathematical models, focused on the grid voltage oriented vectorcontrol method of the double loop. The simulation results show that the dual PWMconverter has the characteristic of Input and output characteristics good, lowharmonics, energy can flow in both directions, high power factor and so on.Proposed the Method of design the double loop PWM converter system regulator byEndometrial control principle .Finally, the paper design s and analyzes the network side of the PWM converterwith LCL filter, and obtained , as the power increases, the converter side of the lineside current THD value decreases, and can be seen as the switching frequencyincreases, the converter Significantly reduce the inductance value side, help toreduce system cost, but the converter will increase heat loss, to be taken into account ,general consideration is needed.