Research On Switching Control Of Multi-Energy Complementary Microgrid

With the rapid development of science and technology,the demand for electricity is increasing.Large power grid has been used as the main power supply channel of human beings because of its unique advantages,but this centralized power supply mode not only has high cost,but also causes irrecoverable harm to the environment.Therefore,flexible,efficient and clean microgrid came into being.But the volatility and randomness of independent distributed power sources such as photovoltaic and wind turbines in microgrid,which makes it very difficult to switch between grid-connected and isolated operation modes safely,smoothly and quickly.This thesis focuses on the switching stability of microgrid in the process of grid-connected/island mode switching operation control.Firstly,the grid-connected operation model and island operation model are established,and they are regarded as two subsystems;Cross backstepping method is used to design the switching controllers of the two subsystems,and the common Lyapunov function is constructed.Therefore,arbitrary switching law can be designed to ensure the stability of the grid-connected subsystem and the off-grid subsystem at any switching time.Then,considering the parameter uncertainty caused by resistance aging and other factors in the actual operation model of microgrid,a microgrid switching system model with uncertain parameters is established,and an adaptive switching controller is designed by combining the adaptive and cross backstepping method,and the common Lyapunov function of the switching system is constructed,so arbitrary switching rules can be designed to ensure the stability of the switching system.Then,in view of the uncertain parameters and external disturbances,such as noise and actuator failure,in the actual system of microgrid,the adaptive sliding mode technology is introduced,and the microgrid switching system model with uncertain parameters and external disturbances is established.The adaptive sliding mode switching controller is designed by integrating the adaptive sliding mode cross backstepping method,and the common Lyapunov function of the switching system is constructed,thus ensuring that any switching law can make the switching system stable.Finally,in order to solve the stability problem of the switching system of battery+photovoltaic+grid connection power supply and battery+photovoltaic network power supply in the multi-energy complementary microgrid,the switching system model is established at first,and then the switching controller is designed by using the cross backstepping method and the common Lyapunov function is constructed to ensure the stability of the switching system under any switching law.