The failure rate of converters is higher than any other components in the directly driven permanent magnet synchronous generator (D PMSG) based wind power generation systems. Contraposing the changes of the system operating characteristics after converter fault

this paper presents a in depth study on the operating conditions of converter after an open circuit fault based on the mathematical model of converters. The studies show that the system is still sustainable after an open circuit fault of a switch tube

but the operation condition of the converter will be affected and the current waves of the corresponding side will distort. The model of D PMSG based wind power generation system is developed using MATLAB/Simulink

and the experiment platform for the D PMSG based wind power generation is given as well. Simulations and experiments are performed under three different types of open circuit faults. The effects of faults on the system operation characteristics are investigated by the calculation and analysis of some key parameters

such as generator side current

grid side current

DC bus voltage

active power output ratio

and total harmonic distortion. The simulation and experimental results show that an open circuit fault in one converter has little effects on the normal operation of the converter at the other side

but waves of the phase currents at the corresponding side of fault components will distort.