Research On Dual PWM Converter Used In Doubly-Fed Wind-Power Generation System

Recently, energy sources consuming increasing continuously and environment empoison being serious gradually, force people to consider new and renewable energy development and utilization, Due to its obvious advantages, wind power has attracted the attention from vast majority countries. The wind power generation technology has also becomes research hotspot of scholars all over the world. The wind power generation system with variable-speed constant-frequency (VSCF) can capture energy as much as possible. In this kind of system, the control and design of the AC-excited power supply are of great importance. This thesis deals with the control of the dual PWM converter which is used in doubly-fed wind-power generation system.At first, the current research situation about the world wind power and wind power generation technology has been covered. After studying the mathematical model in static three-phase coordinate and in rotary two-phase coordinate, the stator field-oriented vector control strategy is issued. Decoupled control of doubly-fed induction generator (DFIG) active and reactive output power are realized. The principle and control of the maximal wind power capture operation have been researched according to the characteristic of the wind power capturing and wind power generator. The results of simulation under MATLAB/SIMULINK validate the validity of the controlling strategy.The topology and mathematical model of grid-side PWM converter are analyzed. Voltage and current double closed-loop control strategy and predictive current control strategy are proposed. The control principle of grid-side PWM converter, the function of which is to control the input power factor at grid side and DC bus voltage, was designed on the basis of the closed-loop field oriented vector control.At last, simulating system of VSCF wind generating is designed based on DSP .It is composed of a 5.5kW DFIG and grid-side and rotor-side PWM converter which controlled by dual DSP controllers. The design of signal processing circuit, IPM drive circuit, quadrature encoder pulse circuit, protection circuit, communication interface circuit and relay output circuit have been detailed proposed.