Fault-tolerant permanent-magnet Vernier cylindrical electric motor with electromagnetic suspension and fault-tolerant vector control method for short circuit of two adjacent phases

Patent metadata

Field	Value
Publication number	US-10505483-B2
Application number	US-201916257178-A
Country	US
Kind code	B2
Filing date	Jan 25, 2019
Priority date	Jul 26, 2016
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

Disclosed are fault-tolerant permanent-magnet vernier cylindrical electric motors with an electromagnetic suspension and a fault-tolerant vector control method for a short circuit of two adjacent phases. The fault-tolerant permanent-magnet vernier cylindrical electric motor with an electromagnetic suspension and the fault-tolerant vector control method for a short circuit of two adjacent phases suppress motor thrust ripples caused by a fault of two adjacent phases of an electric motor. The dynamic performance and the steady-state performance thereof are consistent with those under a normal state, and the switching frequency of a voltage source inverter is constant.

First claim

What is claimed is:

1. A five-phase tubular vernier permanent-magnet (TVPM) motor for electromagnetic suspension comprises an inner stator, an outer stator, and a long mover between the inner stator and the outer stator,
wherein a length of the inner stator and the outer stator is equal and is smaller than a length of the long mover, the inner stator and the outer stator are integrally connected by an E-type non-magnetic material tube which is directly fixed to the carriage, while the suspension spring is installed between the long mover and the E-type non-magnetic material tube, an other side of the long mover is directly connected to a chassis or a tire, the middle opening direction of E-shaped non-magnetic material tube is the moving direction of the long mover,
wherein an air gap g 1 is located between the outer stator and the long mover, an air gap g 2 is located between the inner stator and the long mover, the air gap g 1 and g 2 should satisfy: g 1 >g 2 , and g 1 and g 2 are greater than zero, wherein the inner stator and outer stator are adopted different structures, wherein permanent magnets (PMs) are surface-mounted or embedded in the inner stator, and armature coil windings are placed in the outer stator,
wherein the long mover is composed of n c pieces of flux-modulated rings which are uniformly arranged along an axial direction of the motor, wherein pieces of flux-modulated rings and the inner stator armatures are composed of permeability magnetic material, the non-magnetic material is placed between an adjacent double-piece of flux-modulated rings, the number n c of the flux-modulated rings, the pole pairs n p of the PMs and the pole pairs n w of the coil windings satisfy the following relationship: n c =n p +n w , wherein a vernier modulation effect is achieved.

2. The TVPM motor for electromagnetic suspension of claim 1 , wherein the outer stator comprises an outer stator armature iron core, coil windings, and armature teeth and fault-tolerant teeth (FTT), wherein the outer stator armature iron core is made of permeability magnetic materials, wherein the number of the armature teeth is equal to that of FTT, wherein the FTT interleaving the armature teeth are employed, wherein the FTT is placed between the adjacent double armature teeth, wherein a radial thickness of the FTT is equal to a sum of a radial thickness of the pole shoe and the armature tooth, while the axial thickness of the armature tooth is greater than that of the FTT and less than that of the pole shoe, wherein the coil windings are divided to m phases, and m is a positive integer which is no less than 1, wherein each phase windings are composed of two sets of coil windings, and fractional-slot concentrated-windings and phase separation mode are adopted, only one coil winding is placed in each armature slots, the number of armature teeth is 2m, and the number of FTT is 2m.

3. The TVPM motor for electromagnetic suspension of claim 1 , wherein the PMs in the inner stator can be adopted with radial consequent pole excitation mode, radial alternating excitation mode, axial alternating excitation mode, or arrays excitation mode,
wherein when the PMs are adopted with radial consequent pole excitation mode or radial alternating excitation mode, the PMs are axially segmented to reduce eddy-current loss in the PMs,
wherein when the PMs are in an arrays form to enhance flux-concentrating effect, each pair of PMs has two PM arrays, which is composed of several odd-numbered PMs, wherein the middle PM is alternately excited in the radial direction, while the magnetic directions of the PMs on both sides are pointed into the middle radial excited PM in the axial direction, wherein the number of pole pairs of PMs in inner stator is n p .

4. The TVPM motor for electromagnetic suspension of claim 1 , wherein the motor is configured for a tubular motor with 2*n p /n s pole-slot ratio, wherein the motor is configured to adjust a number of flux-modulated rings to satisfy a modulation ratio according to a different pole-slot radio, wherein a modulation effect is achieved.

5. A fault-tolerant field-oriented control (FT-FOC) method of controlling a TVPM motor for electromagnetic suspension under adjacent double-phase short-circuit faults, the motor comprising five phases, including phase-A, phase-B, phase-C, phase-D, and phase-E, wherein the FT-FOC method under adjacent double-phase short-circuit faults comprises the following steps:
(1) providing a five-phase TVPM motor for electromagnetic suspension model;
(2) providing a TVPM motor for electromagnetic suspension having five stages, including phase-A, phase-B, phase-C, phase-D, and phase-E, wherein when short-circuit faults occur on phase-C and phase-D, it is assumed that only the open-circuit faults occur on the phase-C and phase-D, wherein according to a principle that the traveling wave magneto-motive forces (MMFs) is invariant before and after the faults, the constraint that the sum of the currents in remaining healthy phases is zero, and the constraint that the amplitudes of the currents in phase-B and phase-E are equal, the fault-tolerant currents in the remaining healthy phases of the motor with phase-C and phase-D open-circuit faults are achieved, which can be expressed as

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A

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sin
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Assignees

• Univ Jiangsu

Inventors

• Zhou Huawei
• Lu Zhen
• Liu Guohai
• Zhao Wenxiang
• Ji Jinghua
• Chen Long

Classifications

• H02P29/028

  the motor continuing operation despite the fault condition, e.g. eliminating, compensating for or remedying the fault · CPC title

• H02P21/05

  specially adapted for damping motor oscillations, e.g. for reducing hunting · CPC title

• H02P29/024

  Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load · CPC title

• H02K1/17

  Stator cores with permanent magnets · CPC title

• H02P21/22 Primary

  Current control, e.g. using a current control loop · CPC title