Wenxiang Zhao, Ming Cheng, Ruiwu Cao, Jinghua Ji
2012 Electromagnetic Waves  
Redundant flux-switching permanent-magnet (R-FSPM) motor is a new fault-tolerant machine having PMs in the stator, offering high efficiency, high reliability, and robust structure. This paper proposes two remedial control strategies for fault-tolerant operations of the R-FSPM motor drive in the single-channel (SC) mode. First, by doubling the healthy-channel currents, the reduced torque due to one channel loss can be remedied, the so-called remedial brushless AC (BLAC) operation mode. Second,
more » ... ion mode. Second, by injecting harmonic current (IHC) considering harmonic back-EMF effect, the reduced torque can also be smoothly remedied, the so-c alled remedial IHC operation mode. Finally, both of the proposed remedial control strategies are verified by co-simulation and experimentation, hence confirming the validity of the proposed fault-tolerant R-FSPM motor drive. Permanent-magnet (PM) brushless motor drives are attracting extensive attention in high reliability applications, which are good candidates for EV applications [3] [4] [5] . By employing an arrangement of alternately wound teeth in the stator, a fractional-slot concentratedwindings PM machine, termed as rotor-PM machine, was proposed for fault-tolerant operation [6] . To operate the rotor-PM motor at flux weakening mode, an optimal torque control strategy was proposed in [7] . In addition, multi-phase PM motors have received great attention for fault-tolerant operation. In [8, 9] , a new five phase motor drive was proposed. The proposed control guarantees safe drive operation considering the 3rd harmonic components of back-electromotive-force (back-EMF). However, since PMs are located in the rotor, these conventional rotor-PM brushless machines, including the surfacemounted, inset and interior topologies, suffer from weak mechanical structure and difficulty of PM cooling [10] . Recently, a new class of doubly-salient motors having PMs in the stator, termed as stator-PM motors, has been proposed and investigated [11] . These stator-PM motors include the doublysalient PM (DSPM) type, flux-reversal PM (FRPM) type and fluxswitching PM (FSPM) type. Extensive research work has been performed to analyze this class of machines, showing that stator-PM motors incorporate the merits of high power density, strong mechanical integrity and good immunity from thermal problem. It has been identified that the DSPM motors can inherently offer faulttolerance [12] . Meanwhile, it has been verified that the FSPM motor can offer significantly higher power density than other stator-PM motors [13] [14] [15] . Very recently, by introducing the redundant technique to the FSPM machine topology, a new redundant FSPM (R-FSPM) motor has been proposed [16] . It is most viable for fault-tolerant operation of EVs, since it inherently offers high efficiency, high power density, maintenance-free operation, insignificant thermal influence on PMs and mechanically robust. Also in [16] , control strategies for postfault operation of up to two coils (not in the same channel, e.g., coils-A1 and -B2) have been investigated. However, it can't handle the fault of two or three coils in the same channel, such as coils-A1 and -B1. The purpose of this article is to propose two remedial control strategies for fault-tolerant operations of the R-FSPM motor drive in the single-channel (SC) operation mode. The structure and electromagnetic features of the R-FSPM motor will be briefly described in Section 2. In Section 3, two remedial operations, namely remedial brushless AC (BLAC) operation and remedial injecting harmonic current (IHC) operation, will be proposed. A co-simulation technique will be adopted in Section 4 to assess the performance of the proposed
doi:10.2528/pier11110405 fatcat:ux2mhogbercxlctcnikfytggoe