Bond graph model-based fault accommodation in power electronic systems

The paper presents a bond graph model-based approach to active fault tolerant control (FTC) that makes use of residuals of analytical redundancy relations (ARRs). The latter ones are computed in order to decide whether a fault has occurred. Given a single fault hypothesis can be adopted, an advantage is that the time for isolating a fault among potential fault candidates that contribute to an ARR by means of parameter estimation may be saved and as long as ARR residuals are within their thresholds no input reconstruction at all is needed. It is shown that ARR residuals can be used for estimation of faults that can be isolated. ARR based input reconstruction is demonstrated by application to a buck-converter driven DC motor as a simple example of a switched power electronic system for which an averaged bond graph model is used. Scilab simulation runs confirm analytical results. If a required input cannot be determined analytically, it can be obtained by numerically solving a differential-algebraic equations (DAE) system.