Secondary Frequency Control for Islanded MG Based on Model-free Adaptive Control

The frequency response model of the microgrid (MG) is necessary for the design of the controller when performing secondary frequency control. However, due to such factors as the widespread application of commercial power sources, it is difficult to obtain micro-source models, which naturally increases the difficulty of controller design through mechanism modeling methods. Therefore, this paper proposes a secondary frequency control strategy for islanded MG based on model-free adaptive control (MFAC). Firstly, the problem of secondary frequency control is transformed into the target frequency tracking problem. Then, the model-free adaptive control algorithm and pseudo partial derivative (PDD) estimation and reset algorithm are designed based on the dynamic linear data model of the control system. Further, the regulation of the frequency is realized. This method is independent of the mathematic model of MG and only needs to use the input and output data during the operation of the MG without complex controller parameter tuning. It also has strong adaptability and portability for different MGs. Simulation results verify the effectiveness of the proposed scheme.