双馈风力发电交流励磁电源研究

Research on AC Excitation Doubly-fed Wind Power Generation

目前用于双馈风力发电机的交流励磁电源是背靠背的两电平电压型PWM变换器的主电路结构形式，论文选择电压型结构进行深入研究。在建立三相静止坐标系下PWM变换器的数学模型，得到两相静止坐标系下的数学模型，通过有功功率和无功功率变化率的的求解，给出无差拍预测直接功率控制策略中每个电压矢量作用时间。从消除功率误差和获得最小开关损耗的角度出发，给出PWM变换器直接功率控制中电压矢量选择的基本原则和策略，将电网电压周期划分为12个扇区，基于变换器电压角度位置来划分比基于电网电压角度位置划分更能较小开关损耗，避免辅矢量作用时间不合理的现象，该无差拍预测直接功率控制策略的矢量选择方法不仅实现简单，而且可以消除有功功率和无功功率的稳态误差，减小变换器交流侧电流的谐波含量。

The circuit structure of the two-level back-voltage type PWM converter, which is selected and depth studied in the paper, is currently used for DFIG AC excitation power. The two-phase coordinate mathematical model is given based on the three-phase stationary coordinate mathematical model of the PWM converter is estabhshed. Through the active and reactive power change rate of solving given deadbeat predictive direct power control strategy each voltage vector duration of action. By given the direct power PWM convertor basic principles and policy control vokage vector selected grid voltage cycle will be divided into 12 sectors. To eliminate errors and obtain power from a minimum switching loss perspective used the angular position of the voltage converter to divide ratio better than the angular position of the grid voltage divide into smaller more switching losses and avoid secondary vector time. The deadbeat predictive power direct vector control strategy selection method is not only simple, but also can eliminate the active and reactive power the steady-state error, reduce the harmonic content of the converter AC side current.