Research And Design Of The VSCF System Base On Dual PWM Inverter System

In recent years, with the shortage of conventional energy, seriously air pollution andglobal warming problem, wind energy development has been paid more and more attention.Because compare to other wind power schemes has obvious advantages, doubly fedgeneration scheme occupies a major position of the wind power market which is rapidlyexpanding. Doubly fed wind power generation scheme base on doubly fed inductiongenerator (DFIG) and converter. DFIG stator is directly connected to the electric powersupply grid, high quality of electric energy was generated because the stator current wave issine. As the core of control system, converter can achieve maximum wind energy capture byadjusting DFIG stator active power, and adjust wattless power in the grid by adjusting DFIGstator reactive power.This paper studied around the dual PWM converter of DFIG system, the main researchcontents include control theoretic analysis, simulation, prototype development three aspects,respectively on the gird side and machine side. First, analyzed the control principle of the gridside converter, and the mathematical model of grid side converter, the basic converterprinciple, the method of coordinate transformation, the current decoupling method, powerfactor control method and double closed loop control strategy were discussed. Base on thecontrol strategy of the grid side converter, using Matlab modeling and simulating the gird sideconverter, verified the feasibility of the grid side converter control strategy. Then, analyzedthe control strategy of the machine side converter, the mathematical model of DFIG wasestablished in the three-phase static coordinate system, realized decoupling of the statorpower with coordinate transform and stator voltage oriented method. The method of windgenerator grid-connection with no-load was discussed. Using Matlab modeling and simulatingthe DFIG output power control system, establishment of the system model has guidance forthe follow-up hardware platform and the realization of software algorithm.Finally, this paper discussed the design of the main circuit based on IPM, the controlcircuit base on DSP and CPLD, and the software design of the system, Some experiment wasdone based on Software and hardware platform.