限制转子电流的双馈风电机组虚拟同步控制策略

随着新能源的大规模开发利用,其在能源结构中的占比不断提高。为了维持大电网的平稳运行,要求双馈风机等新能源机组参与电网调频。双馈风机的转子侧变流器存在容量限制,而调频过程中转子电流变化可能会超出此限。为应对这一问题,首先分析了双馈风力发电机的数学模型,并得出了额定转速下dq系的转子电流控制模型；然后使用误差转化函数与李雅普诺夫方法,设计了限制转子电流的控制器,并与常规的虚拟同步控制相结合,提出了一种改进的虚拟同步控制策略,可以兼顾风机调频的需求与调频动态过程中转子电流的限制。通过仿真验证了所提出控制器参与电网调频的能力以及对于转子电流的良好控制。

Rotor Current PerformanceGuaranteed Virtual SynchronousControl for DoublyFed Induction Generators

With the rapid development and high penetration of renewable energy, it is becoming more important that renewable generators, including doublyfed induction generator (DFIG), participate in the frequency regulation of the power grid. However, the rotorside converter (RSC) of DFIGs usually had relatively small current limitations, which could be exceeded during frequency regulation. A novel rotor current performanceguaranteed virtual synchronous controller for DFIGs was proposed. Firstly, the DFIG model was analyzed and a current control model was developed. Then, using an error transformation function and Lyapunov synthesis, a performanceguaranteed controller was proposed to strictly guarantee the rotor current within the predefined bounds. Thus the proposed controller could well deal with the frequency regulation demand and the current limitation. Finally, the effectiveness of the controller was verified via simulations. The enhanced rotor current control effect brought by performanceguaranteed control was also examined.