Observer-based fault diagnosis of power electronics systems

We propose a fault diagnosis method for power electronics systems that extends classical observer-based fault-sensitive detection filters for linear time-invariant systems to switched-linear systems commonly encountered in power electronics. The result is a piecewise-linear detection filter, which in the absence of faults, works the same way as an observer-it predicts the system states exactly. If a fault occurs, the state predicted by the filter differs from the true state of the system, and by appropriately choosing the filter gain, the filter residual has certain geometrical characteristics that makes the fault identifiable. An experimental platform to verify the feasibility of the proposed method is presented along with simulation and experimental results illustrating the feasibility and effectiveness of the method.