Open circuit fault diagnosis technique of charging pile IGBT based on improved sliding mode observer

In order to solve the chattering and misjudgment problems of traditional sliding mode observer (SMO), an improved diagnosis method of sliding mode observer (ISMO) was proposed. By adaptive adjusting observer gain to improve the adaptability of system state, and introducing compensation to correct sliding mode switching error, the observation accuracy was improved. In fault detection, open fault feature extraction method is used to construct fault criteria, and dynamic fault detection strategy is combined to realize rapid and accurate identification of IGBT abnormal state. Experimental tests show that the method can effectively suppress buffeting under different working conditions, improve the sensitivity and accuracy of fault detection, and provide reliable guarantee for the safe operation of the charging pile power conversion system.