Experimental Assessments of a Triple Redundant Nine-Phase Fault-Tolerant PMA SynRM Drive

Abstract

Abstract-Fault tolerant machine drives are key enabling technologies in safety critical applications. The machine drives are expected to exhibit high performance in healthy conditions and accommodate as many faults as possible, namely open circuit or short circuit in the machine and inverter or even an inter-turn short circuit. This paper aims to assess a triple redundant 9-phase (3x3-phase) permanent magnet assisted synchronous reluctance machine (PMA SynRM) drive by comprehensive experimental tests under both healthy and fault conditions on a 35kW machine drive prototype. The healthy performance, fault behavior, fault detection and mitigation strategy are presented and assessed by extensive tests which demonstrate that the machine drive exhibits high performance and excellent fault tolerance with simple and cost-effective implementation. Therefore, the proposed machine drive has proven to be a practical candidate for safety critical applications.

Modeling and Experimental Verification of an Unconventional 9-Phase Asymmetric Winding PM Motor Dedicated to Electric Traction Applications

“…where either voltage, current, flux linkage or the other machine terms can be represented by means of f . The flux linkages in qd0 axes can be written with (10), as shown at the bottom of this page by using (9). In order to continue the analysis, we need to know the stator inductance matrix and magnet flux linkages.…”

Stator Turn Fault Modeling for a Triple Redundant 3 × 3-Phase PMA SynRM

“…However, although the different 3-phase sets are physically, thermally and electrically isolated, they are not magnetically isolated [20,21]. The STF behavior is not only affected by the currents in the fault set, but also influenced by the currents in the other 3-phase sets.…”

“…The electrical isolation is achieved by using three standard 3phase inverters to drive each set. This machine has been shown to be tolerant to the worst short-circuit fault -a single turn STF with application of TSC via inverter as the mitigation action [20]. After TSC, the resultant short circuit phase currents will essentially nullify the flux linkage in the fault turns and consequently, the STF current is reduced to a much lower value which is thermally sustainable for the machine.…”

A Turn Fault Mitigation Strategy Based on Current Injection Technique for a Triple Three-Phase PMA SynRM

“…Further a turn fault can be mitigated by application of TSC to the fault 3-phase set. However, the resultant turn fault current differs depending on fault location in the coils [16,19]. In the worst case, the turn fault current reaches 3.2pu.…”