基于交流励磁双馈电机变速恒频风力发电系统的研究

The Study of AC Excited Doubly-Fed Motor VSCF Wind Power Generation System

能源紧缺问题日益突出,利用最环保、清洁的新能源之一的风能,对于缓解能源压力有着重要的意义。不同于常规风力发电系统,交流励磁双馈风力发电系统其变频策略在转子侧,转子回路仅处理双向流动的转差功率,所以变频器体积小、成本低,而且机电系统之间实现了柔性连接。文章针对双馈电机变速恒频风电系统及其控制策略进行探讨,介绍了整流器的原理,建立了PWM整流器的数学模型,采用矢量控制策略对网侧PWM整流器的有功和无功进行解耦,并推导出表达式。对双闭环整流器结构进行了分析,解释了如何设计控制系统中的调节器,如何确定主电路参数。并对双闭环PWM整流器进行了仿真,得出了仿真结论。采用定子磁链定向的控制方式对定子端有功功率和无功功率进行解耦,借助定、转子间磁链的耦合,推导出转子电压与定子电流间的关系式。搭建了基于定子磁链定向的风力发电系统的控制框图,分析了系统的控制策略,对风速变化时,如何通过调节转子电压来改变转子侧功率流动,从而追踪风机最佳功率的过程进行了详细的阐述。

Because the energy shortage problem has become increasingly prominent,the use of wind which is one of the most environmentally friendly,clean energy to ease the pressure on the energy has an important significance.Different to the conventional wind power generation system,the conversion strategy of AC excited doubly fed wind power generation system is on the side of the rotor and the rotor circuit only deals with bidirectional flow of power,so frequency converter has the advantages of small volume,low cost and electromechanical system realized flexible connection.This article discussed the doubly-fed motor VSCF wind power system and control strategies,introduced the principle of rectifier,established the mathematical model of PWM rectifier.It also used the vector control strategy of grid side PWM rectifier active power and reactive power decoupling to derive the expression.This article explained how to design the controller in the control system and determine the main circuit parameters by analyzing the structure of double closed loop rectifier.The double closed loop PWM rectifier was simulated,and the simulation results were obtained.The stator flux oriented control method was used to decouple the active power and reactive power of stator end.The relationship between rotor voltage and stator current was deduced by coupling of stator and rotor flux linkage.The control diagram based on stator flux orientation of wind power generation system was set up and the system control strategy was analyzed.It also exposed how to adjust the rotor voltage to track the optimum power turbine process when the power flowing changed.