Fault tolerant control of multicellular converter used in shunt active power filter

•Harmonic mitigation in wind energy conversion system based on DFIG.•Three-phase three cells multicellular converter combined with two-level converter used as grid side converter of wind energy conversion system.•Fault tolerant control is applied in order to increase the reliability of multicellular converter. Shunt active power filters (SAPF) topology based on multicellular converter are used in literature to compensate reactive power and mitigate harmonics generated by nonlinear loads with minimum voltage stress and reduced dv/dt, however a failure in switching devices or variation in parameters of multicellular converter injects a faulty current in electric power grid. This impacts power quality, increases mechanical vibrations, accelerates deterioration with increased temperature and can cause catastrophic damage in wind energy conversion system (WECS). Our contribution is the proposition of fault tolerant control (FTC) to increase the reliability of multicellular converter by the combining between multicellular topology and two-level topology. In this paper the multicellular converter is used as grid side converter (GSC) of wind energy conversion system (WECS) in order to mitigate harmonics generated by nonlinear load, minimize the mechanical vibrations, increase the performance and reliability of multicellular converter during switching devices failure and flying capacitor parameters variation. Simulation results demonstrate that total harmonic distortion (THD) of power grid current satisfies the limit of IEEE standard even when a fault occurs in switching devices or in flying capacitors of GSC.