Current behavior-based open-switch fault on-line diagnosis of inverters in PMSM drive systems

Abstract

The power switches of inverters in permanent magnet synchronous motor (PMSM) drive systems are prone to breaking down and may cause open-circuit fault (OC) due to high electrical and thermal stresses. This paper presents an OC fault diagnostic method of inverters in closed-loop controlled PMSM drive systems based on current behavior. A new detection scheme indicating the relationship between the OC fault and the current behavior variation are constructed. This scheme has the ability to detect the fault within one eighth of a current cycle. Meanwhile, a key transition model including 2 faulty states and 1 recovery state for the location of single-switch and double-switch OC faults are proposed for the first time. A total of 21 kinds of OC faults can be rapidly located. Experimental results validate that the proposed method has the advantage of fast fault diagnosis, accurate fault switch location and good robustness.