基于系统辨识建模的微网二次电压频率控制器参数设计方法

在采用由下垂或者虚拟同步机控制的逆变器构建的微网系统中,二次电压频率调节器参数优化是提高微网电压频率性能的关键。进行电压频率参数优化分析的前提是获取微网电压频率响应模型,但是由于微网系统结构复杂多样,系统内微源和负荷种类繁多,以及商业化电源广泛使用造成的电源模型难以获得等原因,给微网机理建模带来了很多困难。为解决上述问题,通过建立微网系统公共连接点电压频率响应模型结构,利用在微网中采样的运行数据以及系统辨识方法对模型中传递函数进行辨识,并利用辨识得到的模型对微网系统二次电压频率控制器进行参数优化。所提方法不仅可以在微网内部结构以及电源模型未知的情况下对微网进行建模,而且所建模型阶次低,便于调节器参数设计使用。最后,在微网实验平台上对所提方法的有效性进行了实验验证。

Parameter Design Method of Secondary Voltage and Frequency Regulation Controller in Microgrid Based on System Identification Modeling

Parameter optimization of secondary voltage and frequency regulation controllers plays a key role in improving voltage and frequency quality in microgrid, especially for a microgrid system which consists of inverters controlled by droop or virtual synchronous generator (VSG) control. In order to complete the process of parameters optimization, the first step is to construct the voltage and frequency response model of microgrid. However, due to the complex structure of the microgrid system, multiple kinds of micro-sources, loads and widely-used commercial power supply, it is difficult to obtain the source model, which brings about lots of difficulties in microgrid mechanism modeling. To solve the above problems, a model structure of voltage and frequency at point of common coupling (PCC) for microgrid system is established. The transfer function in the model is identified by system identification algorithm using operation data sampled in the microgrid, and the parameters of secondary voltage and frequency controller in microgrid system are optimized using identified model. The proposed method can model the microgrid without knowing the internal structure of microgrid or source model, and the order of built model is low which is convenient for parameter planning of regulator. Finally, effectiveness of the proposed method is verified on the test platform for microgrid.