The Simulation Research Of Variable Speed Constant Frequency Doubly Fed Wind Power Generation System

The thesis presents simulation research of the excitation control technique in the VSCF-DFG(variable speed constant frequency-doubly fed generator)system for wind power generation, and the main contents are as follows:In dc-qc synchronous rotating reference frame, the mathematical model of stator-field orientation DFG is constructed, and the vector control method for independent regulation of generator stator output active and reactive power is analyzed.The double-SVPWM ( SVPWM ( space vector pulse width modulation )rectifier-SVPWM inverter)based AC-DC-AC bidirectional converter is adopted as excitation power for the good performance such as approximately sinusoidal input current and adjustable input power factor, as well as independently adjustable frequency, magnitude, and phase of output voltage; the design methods of the DC side capacitance and AC power side inductance of AC-DC-AC bidirectional converter are also analyzed.The control process under rated wind speed of VSCF-DFG for wind power generation is analyzed; the simulation model of DFG is constructed with MATLAB/SIMULINK, and the simulation results show that vector control based DFG not only can quickly response to the separate regulation of stator output active power, stator power factor and slip ratio, but also can obtain good tracking control; the simulation model of double-SVPWM based AC-DC-AC bidirectional converter excited VSCF doubly fed wind power generation system with stator-field orientation vector control is constructed, then the simulation research of regulation properties of stator output active power in three generation modes of sub, super, and cross synchronous speed and stator output reactive power is carried out, and the simulation results verify feasibility of control strategy for the system; the double-SVPWM based bidirectional converter is compared with double-SPWM(SPWM(sinusoidal pulse width modulation)rectifier-SPWM inverter), and the simulation results show that the former has higher utilization coefficient of DC voltage and lower THD(total harmonic distortion factor)of excitation voltage(current), which better satisfies the excitation control requirement of VSCF-DFG system for wind power generation.The work of this thesis will be helpful to the application research of excitation control technique in VSCF-DFG system for wind power generation.