An Online Open-Circuit Fault Diagnosis and Fault Tolerant Scheme for Three-Phase AC-DC Converters with Model Predictive control

Abstract

This paper proposes an open-circuit fault diagnosis and fault-tolerant control to enhance the reliability of the AC-DC converter using model predictive control (MPC). A fault diagnosis method, which takes advantage of the known and unchanged switching state is proposed to identify single open-circuit fault. By introducing the healthy leg variables (HLVs), a generalized model including both normal and faulty operations is proposed and the fault-tolerant scheme can be integrated into the normal MPC scheme. With the proposed generalized model and fault- tolerant scheme, the AC-DC converter can autonomously recover from open-circuit faults and the continuous operation of three- phase AC-DC converters is maintained. Both the fault diagnosis and fault-tolerant schemes are based on the stationary frame, the phase-locked loop (PLL) is eliminated. Experimental results are presented to validate the effectiveness of the proposed integrated fault diagnosis and tolerant scheme.