Networked control of distributed energy systems

This thesis reports a new method for stability analysis and maximum time delay estimation in networked control systems with applications to distributed energy systems. The proposed new method is based on using finite difference approximation for the delay term and then the Lyapunov system stability theorem is applied to derive the time delay boundary allowed to the system. The proposed method has been applied to networked control systems with state feedback controllers, with dynamic controllers, and to multi-units interconnected networked control systems. The proposed method is then extended to a class of networked control system with bounded nonlinearity and uncertainties. It is found that increasing the nonlinearity in the system will result in decreasing the maximum allowable time delay. Compared with most of the methods reported in the published literature, the new method is simple to use while the results are comparable. When the time delay is modelled using Markov Chain the stability of the networked control system is formulated as finding the solutions for Bilinear Matrix Inequalities. An improved V-K iteration algorithm is used to solve the Bilinear Matrix Inequalities in order to derive a controller to stabilize the systems.