The Research On Direct Power Control Of Grid-connected Converters For Wind-power Generation System

Wind-power generation industry is growing rapidly now and in the following dozens of years all over the world. The dissertation focuses on the Direct Power Control of grid-connected three-phase voltage source PWM rectifiers in the experiment platform, which is used for the Direct-driven PMSM wind-power generation system.The dissertation establishes mathematical models of three-phase voltage source PWM rectifier in three-phase static coordinate system, two-phase static coordinate system and two-phase rotational coordinate system. Based on this, the dissertation analyses the Direct Power Control method and represents the process to realize it in detail. The method of main circuit design of three-phase voltage source PWM rectifier with Direct Power Control is narrated in the dissertation. The simulation demonstrates the viability of the method. The dissertation also gives some improvement methods to the normal Direct Power Control.The dissertation also introduces the most frequently used control method-voltage space vector.The main circuit and control circuit of the wind-power generation experiment platform are introduced. The control circuit includes power supply board, digital I/O board, DSP control board, drive board, drive powers supply board. The DSP control board has circumstantial description, including CPU unit, analogy signal disposal circuit and communicate unit. The dissertation simply introduces the program of the Direct Power Control, and gives some flow charts.The dissertation carries out single inverter test under zero load, back-to-back test of grid-connected converters, system test under partly load, system test with VSR rectifiers and system dynamic test with VSR rectifiers. The result confesses that the design requires have been achieved.