Ma Dazhong

Fault tolerant synchronization of chaotic systems based on T–S fuzzy model with fuzzy sampled-data controller

In this paper the fault tolerant synchronization of two chaotic systems based on fuzzy model and sample data is investigated. The problem of fault tolerant synchronization is formulated to study the global asymptotical stability of the error system with the fuzzy sampled-data controller which contains a state feedback controller and a fault compensator. The synchronization can be achieved no matter whether the fault occurs or not. To investigate the stability of the error system and facilitate the design of the fuzzy sampled-data controller, a Takagi–Sugeno (T–S) fuzzy model is employed to represent the chaotic system dynamics. To acquire good performance and produce a less conservative analysis result, a new parameter-dependent Lyapunov–Krasovksii functional and a relaxed stabilization technique are considered. The stability conditions based on linear matrix inequality are obtained to achieve the fault tolerant synchronization of the chaotic systems. Finally, a numerical simulation is shown to verify the results.

Storage control strategy for energy hub of We-Energy in the energy internet

This paper consider the role of energy hub in We-Energy (WE). WE is a novel energy accessing mode in order to match up Energy Internet. This new mode is proposed for the convenience of energy regulation, energy trading and information interaction. A new power flow expression of energy hub which contain storage is given in order to overcome the disadvantage of traditional power flow expression. The comparison between new power flow expression and traditional expression is also given in this paper. This study also investigates the optimal operation of using storage systems. To avoid the influence of forecast accuracy, a new control strategy of storages without the forecast based on historical data has been proposed in which economic problem has been given for an energy hub include both electricity, natural gas and heating storage. This new control strategy determines the optimal storage operation to minimize the total energy cost of the hub contained by WE. The proposed control strategy has been applied to two simple case studies which are used to compare the economic cost between the energy hub contain storage or not. The obtained simulation results demonstrate that the new control strategy can make great economic benefit for energy hub contain storage system.

Power Flow Calculation in the Voltage Output Stage

The distribution system represents the final stage in the transfer of power to the individual customers. In the distribution system analysis, the power flow calculation is the most basic and important calculation and is the foundation of the operation, plan, security, reliability analysis and optimization of the power system and is the foundation and springboard of the various electromagnetic transient analysis. A lot of uncertain factors exist in the distribution system. Uncertainty in the distribution system must be addressed in any analysis. In this situation, traditional certain power flow methods have limitation. The flow calculation in the fault condition is studied. The forward-backward sweep method is adopted to calculate fault power flow. The simulation research shows that the calculation results with the polynomial load model are proper in the practical application when the fault occurs.

New fuzzy hyperbolic fault detection filter for a class of nonlinear time-delay systems via LMI approach

In this paper, the fuzzy hyperbolic fault detection filter design problem for a class of uncertain nonlinear time-delay systems with unknown inputs is studied. The basic idea of our study is to use a reference residual model to formulate the fuzzy hyperbolic fault detection filter as a H∞ model-matching problem. The reference residual model designed according to the performance index is an optimal residual generator, which takes into account the robustness against disturbances and sensitivity to faults simultaneously. By using H∞ optimization control technique, the condition of the fuzzy hyperbolic fault detection filter for a class of nonlinear time-delay systems with unknown inputs are then presented via a linear matrix inequality formulation. An illustrative design example is employed to demonstrate the effectiveness of the proposed approach.