Interturn Fault Severity Monitoring in Symmetrical Six-Phase PMSMs Using Subspace Negative-Sequence High-Frequency Current Residuals
Huidong Wang, Jianhui Hu, Yong Li
Abstract
This article proposes a fault severity monitoring method for interturn short-circuit fault (ISCF) based on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xy</i> subspace negative-sequence high-frequency (HF) current residuals in symmetrical six-phase permanent magnet synchronous machines. For six-phase machines, both the fundamental frequency and HF behaviors in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xy</i> subspace can be used to design fault indicators. However, another fault type, high-resistance connection faults (HRCFs) can cause similar <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xy</i> subspace fundamental current symptoms to ISCF. To avoid incorrectly identifying HRCF as ISCF, the proposed method uses the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xy</i> subspace negative-sequence HF current residuals to reduce the sensitivity to the HRCF. Moreover, the proposed method has high robustness for different work conditions and does not need additional sensors. Experimental results show the effectiveness of the proposed method for different fault severities and operations.