This study focuses on the design of the robust fault-tolerant control (FTC) system based on adaptive observer for uncertain linear time invariant (LTI) systems. In order to improve robustness, rapidity, and accuracy of traditional fault estimation algorithm, an adaptive fault estimation algorithm (AFEA) using an augmented observer is presented. By utilizing a new fault estimator model, an improved AFEA based on linear matrix inequality (LMI) technique is proposed to increase the performance. Furthermore, an observer-based state feedback fault-tolerant control strategy is designed, which guarantees the stability and performance of the faulty system. Moreover, the adaptive observer and the fault-tolerant controller are designed separately, whose performance can be considered, respectively. Finally, simulation results of an aircraft application are presented to illustrate the effectiveness of the proposed design methods.

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Distribution network reconstruction is important for the reliable operation of distribution network. This paper establishes a mathematical model by using random weight for multi-objective optimization. A new algorithm is proposed based on binary particle swarm optimization (BPSO) algorithm, which can quickly adjust topology and cut off load in limit state. The new algorithm improves the distribution network’s reliability with the advantages of lowest power loss, better load balance and highest power supply capacity. Finally, the performance of the proposed method is tested on IEEE 33-node power distribution system.

HVDC system based on modular multilevel converter(MMC) usually adopts fixed DC bus voltage to realize the start-up control of converter, which will have a great impact on AC network during charging process. This paper presents a constant power start-up control strategy based on MMC arm current control, which can effectively control active power, reactive power, output current and submodule(SM) capacitor voltage. Based on the existing two-stage start-up control mode, according to the output characteristics of arm voltage in controlled charging process, the circuit topology of DC side open circuit of converter is proposed, and the mathematical model is established. Based on the derived instantaneous arm power calculation method and the average sliding filter of SM capacitor voltage, the double closed-loop fast response controller of fixed AC power in controlled precharging stage is given. The safety of the power electronic equipment in the converter is effectively guaranteed and the impact of converter on ac power grid is greatly reduced. Finally, simulation models of conventional start-up method and proposed start-up method are built on MATLAB/Simulink platform to verify the validity and correctness of the proposed start-up control strategy.