PATENT CLAIM ANALYSIS

Application Number: 15748926
Application Type: Utility
Filing Date: 2018-01
Publication Date: 2019-01
Patent Classification: ["318", "400020"]

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.

Claim (Index 6):
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 includes the following steps:\n (1) establishing the model of five-phase IPM-FTLM; (2) dividing an IPM-FTLM into five phases: phase-A, phase-B, phase-C, phase-D and phase-E; wherein when the short-circuit faults occur in phase-B and phase-E, it is assumed that the open-circuit faults only occur in phase-B and phase-E, according to the principle of constant traveling-wave magnetic motive force (MMF) before and after fault; and wherein and the constraint about the sum of healthy phase currents is zero, and also the constraint about the amplitude of two adjacent phase-C and phase-D currents is equal, the healthy phase currents of fault-tolerant operation can be obtained after the open-circuit faults occur in phase-B and phase-E: { i A * = 1.381 \ue89e ( - i q * \ue89e sin \ue8a0 ( \u03b8 ) + i d * \ue89e cos \ue8a0 ( \u03b8 ) ) i C * = 2.235 \ue89e ( - i q * \ue89e sin ( \u03b8 - 3 5 \ue89e \u03c0 ) + i d * \ue89e cos ( \u03b8 - 3 5 \ue89e \u03c0 ) ) i D * = 2.235 \ue89e ( - i q * \ue89e sin ( \u03b8 + 3 5 \ue89e \u03c0 ) + i d * \ue89e cos ( \u03b8 + 3 5 \ue89e \u03c0 ) ) ; where i d * i q * are d-axis and q-axis current references in the synchronous rotating frame, respectively, \u03b8 = \u222b \u03c0 \ue89e \ue89e v \u03c4 \ue89e dt is electric angle, \u03bd is the electric speed of secondary, and \u03c4 is pole pitch;\n (3) transforming the variables in the remaining three-healthy-phase natural frame into the two-phase stationary frame with the extended Clark transformation matrix T post , which is three columns and two rows; wherein the inverse transformation matrix T post \u22121  is two columns and three rows; wherein T post , T post \u22121  and transposed matrix T post T  are obtained according to the healthy phase currents: \n T post = [ 0.618 \ue89e cos \ue89e \ue89e 0 1.28 cos \ue89e \ue89e 3 \ue89e \ue89e \u03c0 5 1.28 cos ( - 3 \ue89e \u03c0 5 ) 1.28 0 sin \ue89e 3 \ue89e \u03c0 5 4.043 sin ( - 3 \ue89e \u03c0 5 ) 4.043 ] T post - 1 = 2.235 \ue8a0 [ 0.618 \ue89e cos \ue89e \ue89e 0 0 cos \ue89e 3 \ue89e \u03c0 5 sin \ue89e 3 \ue89e \u03c0 5 cos ( - 3 \ue89e \u03c0 5 ) sin ( - 3 \ue89e \u03c0 5 ) ] T post T = [ 0.618 \ue89e cos \ue89e \ue89e 0 1.28 0 cos \ue89e 3 \ue89e \u03c0 5 1.28 sin \ue89e 3 \ue89e \u03c0 5 4.043 cos ( - 3 \ue89e \u03c0 5 ) 1.28 sin ( - 3 \ue89e \u03c0 5 ) 4.043 ] (4) restraining thrust force fluctuation caused by the short-circuit currents of fault phases with the healthy phase currents; wherein after calculating the short-circuit compensation currents (i A \u2033 i C \u2033 i D \u2033) of healthy phases which used to restrain thrust force fluctuation caused by the short-circuit currents of fault phases, the short-circuit compensation currents (i A \u2033 i C \u2033 i D \u2033) are transformed into currents (i \u03b1 \u2033 i \u03b2 \u2033) in two-phase stationary frame by using the extended Clark transformation matrix T post ; (5) transforming the remaining healthy three-phase currents (i A i C i D ) in natural frame into the currents (i \u03b1 \u2032 i \u03b2 \u2032) in two-phase stationary frame by using the extended Clark transformation matrix T post , and then the currents (i \u03b1 \u2032 i \u03b2 \u2032) subtract the currents (i \u03b1 \u2033 i \u03b2 \u2033) obtained in Step 4, and obtaining the currents (i \u03b1 i \u03b2 ); wherein the Park transformation matrix C 2s/2r  is used to transform the currents (i \u03b1 i \u03b2 ) into the currents (i d i q ) in the synchronous rotating frame; (5\u2032) subtracting the short-circuit compensation currents (i A \u2033 i C \u2033 i D \u2033) of healthy phases from the remaining healthy three-phase currents (i A i C i D ) in national frame, obtaining (i A \u2032 i C \u2032 i D \u2032) which are transformed into the currents (i d i q ) in synchronous rotating frame according to the extended Clark transformation matrix T post  and Park transformation matrix C 2s/2r ; (6) establishing the mathematical model of the five-phase IPM-FTLM with two nonadjacent short-circuit phase faults in the synchronous rotating frame; (7) designing the first-order inertia voltage feed-forward compensator, wherein the feed-forward compensation voltages (u d comp u q comp ) can be obtained by the current references (i d * i q *) of synchronous rotating frame going through the first-order inertia \u03c9\u03b1 s + \u03b1 ; and wherein control voltages (u d0 u q0 ) can be obtained by the difference values, which are generated by the current references (i d * i q *) subtracting the feedback currents (i d i q ), going through the current internal mode controller \u03b1 \ue89e \ue89e L ( 1 + R sL ) ; and wherein the sums of the control voltages (u d0 u q0 ) and the feed-forward compensation voltages (u d comp u q comp ) are the voltage references (u d * u q *) in the synchronous rotating frame; and wherein the voltage references (u d * u q *) can be transformed into voltages (u \u03b1 * u \u03b2 *) in two-phase stationary frame by using Park inverse transformation matrix C 2r/2s ;\n (8) observing the back electromotive forces (EMFs) (e A e C e D ) of the healthy phases by the back-EMF observer according to T post T , C 2r/3s  and the permanent magnet linkage of the secondary: \n [ e A e C e D ] = \u03c9 ( T post T \ue89e C 2 \ue89e r / 2 \ue89e s \ue8a0 [ 0 2.5 \ue89e \u03bb m ] + 0.206 \ue89e \u03bb m \ue89e sin \ue89e \ue89e \u03b8 \ue8a0 [ 1 1 1 ] ) wherein the back-EMFs (e B e E ) of the faulty phases can be calculated according to the back-EMFs (e A e C e D ) of healthy phases: \u2003 { e B = e A + e C 2 \ue89e cos \ue89e 2 \ue89e \u03c0 5 e E = e A + e D 2 \ue89e cos \ue89e 2 \ue89e \u03c0 5 (9) verifying that the remaining healthy phase of the motor can output the short-circuit compensation currents (i A \u2033 i C \u2033 i D \u2033), which used to restrain thrust force fluctuation caused by short-circuit currents; wherein the short-circuit compensation voltages of the remaining healthy three-phases (u A \u2033 u C \u2033 u D \u2033) can be defined as { u A \u2033 = 0.1708 \ue89e ( e B + e E ) u C \u2033 = 0.7236 \ue89e e B - 0.8944 \ue89e e E u D \u2033 = - 0.8944 \ue89e e B + 0.7236 \ue89e e E , according to the relationship between phase-B short-circuit current i B =i sc _ B ; and wherein phase-B back-EMF e B , the relationship between phase-E short-circuit current i E =i sc _ E ; and phase-E back-EMF e E , and the mathematical expression of short-circuit compensation currents; wherein short-circuit compensation currents can be transformed into the short-circuit compensation voltages \u2003 { u \u03b1 \u2033 = 0.1237 \ue89e ( e B + e E ) u \u03b2 \u2033 = 0.3806 \ue89e ( e B - e E ) in two-phase stationary frame by using the extended Clark transformation matrix T post ;\n (10) adding the voltage references (u \u03b1 * u \u03b2 *) in two-phase stationary frame and short-circuit compensation voltages (u \u03b1 \u2033 u \u03b2 \u2033) are added up to the voltage references \n { u \u03b1 ** = u \u03b1 * + 0.1237 \ue89e ( e B + e E ) u \u03b2 ** = u \u03b2 * + 0.3806 \ue89e ( e B - e E ) ; wherein the voltage references (u \u03b1 ** u \u03b2 **) can be transformed into the voltage references (u A * u C * u D *) in national frame by using the extended Clark inverse transformation matrix T post \u22121 ; wherein voltage references (u A * u C * u D *) and the back-EMFs (e A e C e D ) of the remaining healthy phases are added up to the expected phase voltage references (u A ** u C ** u D **), respectively;\n (10\u2032) transforming the voltage references (u \u03b1 * u \u03b2 *) in two-phase stationary frame into the voltage references (u A * u C * u D *) in natural frame by using the extended Clark inverse transformation matrix T post \u22121 ; wherein the voltage references (u A * u C * u D *) add the short-circuit compensation voltages (u A \u2033 u C \u2033 u D \u2033) of remaining three healthy phases; wherein expected voltage references (u A ** u C ** u D \u2033) can be obtained by adding the back-EMFs (e A e C e D ) of the remaining healthy phases, respectively; and \n (11) reacting to the occurrence of two nonadjacent short-circuit phase faults the expected voltage references (u A ** u C ** u D **) of Step 10 are passed through the voltage source inverter, then the fault-tolerant vector non-disturbed operation of five-phase IPM-FTLM is accomplished by adopting carrier pulse width modulation (CPWM) method.

Metadata:
- Claim Count in Document: 9.0
- Percentile: 86.0
- Lexical Diversity: 1.87931
- Patent Class: 318.0
- Transitional Phrase Type: none
- Component Type: 0
- Foreign Priority: True
- Related Applications: ['15741629', '12720366', '14797940', '13859304', '12838442']

Analysis Scores:
- 35 USC 101 Eligibility (BERT): 0.6597734794860424
- 35 USC 102 Novelty (BERT): 0.5151261947629268
- Combined Prediction Score: 0.6453087510137309
- Mean Citation Score: 235.027966
- Max Citation Score: 273.48117
- Similarity Product: 189.5962004797429

Labels:
- Claim Label 101: 1
- Claim Label 102: 1
- Claim Label 103: 1
- Claim Label 112: 0
- Combined Label: 1
- Label 101 Adjusted: 1

Dataset: test