Research On A4-phase Fault-tolerant PMSM Motor For Electric Vehicle Applications

As electric vehicles gain world-wide popularity, it’s necessary that EVs have ahigh reliability. The multi-phase machine, with its high power density and efficiency,is suitable for electric vehicle applications. What’s more, the multi-phase machine iscapable of faut-tolerance once properly designed. This paper focuses on the researchon a4-phase faut-tolerant PMSM motor, which is able to produce the same torque asbefore faulted for a period of time.First of all, his paper lists the requiements of multi-phase faut-tolerant PMSMmachines and their desigh priciples. With necessary analysis, this paper arrives at a14slots/16poles4-phase faut-tolerant PMSM, where fractional-slot concentratedwindings are applied. EMF of the windings are analysed and harmonic waves aregiven.Then, a model is designed with MathCAD and analyzed by Flux priliminarily.Magentic density, back EMF and no-load torque are studied. To get a better backEMF, so much measures are taken as varying embrace and applying eccentricity topermanent magnets. The back EMF reaches the lowest THD of5.6%when embraceis0.7and the difference between the thickest part and the thinnest of a PM is1.5mm.Finally, fauty conditions, including one-phase open, two-phase open andone-phase short conditions, are analyzed and simulated by Matlab and Flux, on thebasis of which, two current control strategies are compared. Furthermore, theone-phase short-cicuit fault is simulated, proving the motor’s capability to suppressshort-circuit current.