Research On Fault Tolerant Control Of Uncertain Island AC Micro-grid System

As people's increasing demand for electrical energy has caused two serious problems:energy crisis and air pollution.Along with this,scholars from various countries have proposed distributed power generation technology to make it more effectively applied to the power system to achieve uninterrupted power supply to users.The proposal of micro-grid has avoided the disadvantages of distributed power generation and traditional power grid,and improved the utilization rate of distributed power and the continuous power supply time of the system.With the extensive promotion of micro-grids,its stability and reliability have become the focus of research.In this paper,the problem of disturbed uncertain island AC micro-grid control system,considering the failure faults of the actuator,is studied on the problem of robust fault diagnosis and fault-tolerant control.The main contents are summarized as follows:1)According to the topology map of the AC micro-grid system in the island mode,using Kirchhoff's law and Clarketransformation,the system is established under the situation that the micro-grid has the internal parameter perturbation and the external finite energy disturbance coexist in the actual operation,The state space model laid the foundation for the establishment of closed-loop failure models in subsequent chapters.2)Aiming at the disturbed uncertain island AC micro-grid control system,considering all possible actuator failure faults in the system,a robust H_?reliable fault-tolerant control method based on state feedback is proposed.Using the idea of integrity control and LMI toolbox,an appropriate Lyapunov function is constructed,a fault-tolerant controller with fixed gain is designed offline,and the method is simulated and verified.3)Aiming at possible actuator jamming failures and partial failures in the system,an adaptive H_?compensation control method is proposed.This method expands the possible failure range of the actuator,and increases the adjustability of the design method,and improves the conservative problem of the controller designed by the control method;adjusts the controller parameters online through the constructed adaptive law to compensate for the impact of the fault on the system in real time.4)From the perspective of fault type,the above two control methods have designed a fault-tolerant controller for uncertain island AC micro-grid system.However,the two methods consider the complexity and the form of actuator failure to be single,which makes the designed controller more conservative.Combining their respective advantages and considering the unpredictable system state,an active-passive hybrid fault-tolerant control method based on an adaptive fault estimation observer is proposed.First,designing fault-tolerant controller offline to mitigate system performance degradation and have a certain ability to suppress external interference;meanwhile,using adaptive fault estimation observers to estimate fault and state information;then,reconstructing the controller based on real-time fault information;finally,using MATLAB simulation platform to verify the effectiveness of the proposed method.