Quasi-Fault-Tolerant Control for Open-End Winding Five-Phase PMSM With High-Resistance Connection Failure Using Time-Variant Transform Techniques

In the field of electrified ship propulsion, system reliability is paramount due to the essential nature of continuous operation. Multiphase permanent magnet synchronous motors (PMSMs) are vital for their high efficiency and power density. Nonetheless, system reliability may be jeopardized by high-resistance connections (HRCs) failure, which can cause performance to deteriorate and may lead to open-circuit failures. To address the existing HRC fault-tolerant control (FTC) failure to achieve the same performance during normal and FTC operations, this study introduces a quasi-FTC (QFTC) strategy without needing algorithmic switching when HRC failure occurs. The proposed QFTC strategy utilizes a time-variant transformation technique to dynamically regulate the current reference output, compensating for resistance variations encountered during HRC failure. The QFTC strategy proactively manages electrical parameters when HRC failure occurs, thereby reducing power losses, preserving torque output, and enhancing the reliability of the propulsion system. Finally, the effectiveness of the proposed QFTC strategy is verified through experimental validation. The experimental results show that the proposed QFTC strategy increases the drive system efficiency by up to 3.36% compared to the one without FTC.