Abstract:

The residual chi-square test method is difficult to detect and isolate accurately, the improved SPRT (sequential probability ratio test) method can detect the fault by iterative recurrence, but there is a delay and it is not sensitive to the end of the fault. Based on this, this paper analyzes the method of differentiating the size of the fault amplitude, and proposes a fault-tolerant method based on the fading memory idea. When the improved SPRT method detects the fault, the system is isolated and reconstructed. The filter is updated with the data that does not contain the fault information, and the fading factor is used to reduce the weight of the fault information so as to improve the filtering accuracy. Meanwhile, constructing the pseudo normal state, so that the method can judge the end of the fault in time. Simulation results show that the proposed method is suitable for multiple faults, which can improve filtering accuracy and enhance system reliability.

Key words: size of the fault amplitude, fading memory, pseudo normal state, judgment of the fault ending time