Fault-tolerant field-oriented control method of five-phase interior permanent-magnet linear motor under two nonadjacent short-circuit phase faults

Patent metadata

Field	Value
Publication number	US-2019006973-A1
Application number	US-201615748926-A
Country	US
Kind code	A1
Filing date	Aug 17, 2016
Priority date	Jul 26, 2016
Publication date	Jan 3, 2019
Grant date	—

Abstract

The invention proposes a fault-tolerant field-oriented control method of five-phase interior permanent-magnet fault-tolerant linear motor (IPM-FTLM) with two nonadjacent short-circuit phase faults. Firstly, the extended Clark transformation matrix can be obtained according to the principle that magnetic motive force (MMF) keeps constant before and after the two-phase open-circuit faults, the constraint that the sum of healthy phase currents is zero and the adjacent two-phase current amplitude is equal. The back electric motive force (EMF) can be estimated by the transposed matrix. The nonlinear strong coupling system becomes the first-order inertia system when using the internal mode controller, the first-order inertia feed-forward voltage compensator and back-EMF observer, as the motor is with fault. Then, according to the principle that the sum of MMF of the healthy phase short-circuit compensation currents and two phases short-circuit fault currents is zero, the short-circuit compensation voltage can be obtained, and then these voltages add vector-controller output voltages, respectively. The invention not only restrains the thrust force fluctuation caused by two nonadjacent short-circuit phase faults, but also more importantly keeps the same dynamic and steady performance as the normal conditions, and also it has the constant switching frequency of voltage source inverter.

First claim

1 . (canceled)

2 . The fault-tolerant field-oriented control method of five-phase IPM-FTLM with two nonadjacent short-circuit phase faults of claim 6 wherein:
when the open-circuit phase faults only occur in phase-B and phase-E, it just needs to set the short-circuit compensation currents to zero in Step 4 and to set the short-circuit compensation voltages to zero in Step 9; This fault-tolerant field-oriented control method can achieve fault-tolerant operation of five-phase IPM-FTLM under the condition of two nonadjacent open-circuit phase faults;
when the open-circuit fault occurs in phase-B and short-circuit fault occurs in phase-E, it only needs to set the expression of short-circuit compensation current i sc _ B =0 in Step 4, and to set the expression of short-circuit compensation voltage e B =0 in Step 9; This fault-tolerant field-oriented control method can achieve fault-tolerant operation of five-phase IPM-FTLM under phase-B open-circuit fault and phase-E short-circuit fault;
when the short-circuit fault occurs in phase-B and the open-circuit fault occurs in phase-E, it just needs to set the expression of short-circuit compensation current i sc _ E =0 in Step 4, and to set the expression of short-circuit compensation voltage e E =0 in Step 9; This fault-tolerant field-oriented control method can achieve fault-tolerant operation of five-phase IPM-FTLM under phase-B short-circuit fault and phase-E open-circuit fault.

3 . The fault-tolerant field-oriented control method of five-phase IPM-FTLM with two nonadjacent short-circuit phase faults of claim 6 wherein Step 4 further comprises:
(4.1) supposing that phase-B and phase-E short-circuit currents are i sc _ B =I f cos(ωt−θ fB ) and i sc _ E =I f cos(ωt−θ fE ), respectively; where, I f is the amplitude of short-circuit current, and θ fB is angle between back-EMF of phase-B and short-circuit current of phase-B, θ fE is angle between back-EMF of phase-E and short-circuit current of phase-E, ω=πν/τ, ν is electric speed of the secondary and τ is pole pitch;
(4.2) according to the principle that the sum of healthy phase compensation currents used to restrain the thrust force fluctuation caused by short-circuit fault-phase currents is zero, and the sum of MMFs generated by the healthy phase compensation currents and short-circuit fault-phase currents is zero; obtaining the short-circuit compensation currents (i A ″ i C ″ i D ″) of healthy phases can be obtained:

{

i
A
″

=

-
0.1708



(

i
sc_B

+

i
sc_E

)

i
C
″

=

-
0.7236



i
sc_B

+

0.8944


i
sc_E

i
D
″

=

0.8944


i
sc_B

-

0.7236


i
sc_E

.

(4.3) transforming the healthy phase compensation currents (i A ″ i C ″ i D ″) with the extended Clark transformation matrix T post into the short-circuit compensation currents (i α ″ i β ″) in two-phase stationary frame, and it can be obtained:

{

i
α
″

=

-
0.1237



(

i
sc_B

+

i
sc_E

)

i
β
″

=

-
0.3806



(

i
sc_B

-

i
sc_E

)

Assignees

• Univ Jiangsu

Inventors

• Zhou Huawei
• Liu Guohai
• Ji Jinghua
• Zhao Wenxiang
• Chen Qian
• Chen Long

Classifications

• H02P21/50

  Vector control arrangements or methods not otherwise provided for in H02P21/00- H02P21/36 · CPC title

• B60K1/00

  Arrangement or mounting of electrical propulsion units (B60K7/00 takes precedence; arrangement or mounting of plural diverse prime-movers for mutual or common propulsion B60K6/00) · CPC title

• H02P29/0243

  the fault being a broken phase · CPC title

• H02P21/22

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

• H02P21/14 Primary

  Estimation or adaptation of machine parameters, e.g. flux, current or voltage · CPC title