Open-Switch Fault Detection Based on Open-Winding Five-Phase Fault-Tolerant Permanent-Magnet Motor Drives

Abstract

The difficulty of open-switch fault detection in an open-winding inverter is that the fault at the diagonally opposite position within the H-bridge power cell has the same fault characteristics. To solve this problem, this paper proposes an open-switch fault detection method based on open-winding (OW) five-phase fault-tolerant permanent-magnet (FPFTPM) motor drives. The detection method includes three steps: first, the drives open-switch fault is detected by monitoring the component of the third harmonic residual in the stationary reference frame; second, the least squares iterative method based on the forgetting factor is used to identify the relationship between the residual components, which determines the faulty phase and the faulty phase current type; third, an online current injection test method is proposed to accurately identify the open-switch within the H-bridge power cell. Based on the above steps, the open-switch fault at the diagonally opposite position within the H-bridge power cell could be accurately identified. The novelty of the proposed method lies in the possibility that the open-switch fault detection of any switches within the one H-bridge power cell could be accurately achieved by an online current injection test and does not require hardware changes. The experimental results demonstrate the effectiveness of the proposed detection method.