Fault-tolerant control method for turn-to-turn short circuit fault of five-phase FTFSCW-IPM motor based on open winding

Abstract

The invention provides a turn-to-turn short circuit fault-tolerant control method based on an open-winding five-phase FTFSCW-IPM motor, and the method comprises the following steps: building an open-winding five-phase FTFSCW-IPM motor mathematical model which comprises a flux linkage, a voltage, a torque and a motion equation; after the turn-to-turn short circuit fault is detected, an external resistor is connected, the fault reconstruction of the driving system is carried out, and a fault-tolerant control strategy is formulated for the reconstructed open-phase fault; and formulating a turn-to-turn short circuit fault-tolerant control strategy based on feed-forward compensation for the turn-to-turn short circuit fault and the open-phase fault after system reconstruction. The fault phase is connected with the external resistor, so that the short-circuit current of the fault phase can be effectively reduced, further diffusion of the fault is avoided, and stable and reliable operation of the open-winding five-phase motor driving system is ensured.

Description

Technical Field

[0001] The present invention relates to the field of multi-phase motor control, and in particular to a turn-to-turn short-circuit fault-tolerant control method based on an open-winding five-phase FTFSCW-IPM motor. Background Art

[0002] The open-winding five-phase permanent magnet fault-tolerant motor has excellent fault-tolerant performance, small torque ripple and wide speed regulation range, and has therefore received widespread attention and research in high-reliability fields such as electric vehicles.

[0003] In the open-winding motor drive system, due to the redundancy of power devices, the motor body becomes a vulnerable link that is prone to failure. Among them, the turn-to-turn short-circuit fault related to the motor winding is a relatively serious motor body fault. After the fault occurs, the fault phase will generate a large short-circuit current and bring torque pulsation, endangering the personal safety of the driver and passengers. In order to improve the operating ability of the drive system under the turn-to-turn short-circuit fault, two aspects can be considered. On the one hand, from the perspective of motor body design, the short-circuit current can be reduced through special slot-pole matching and fault-tolerant design to achieve phase-to-phase electrical, magnetic and thermal isolation; on the other hand, the torque pulsation can be suppressed by reconstructing the control strategy after the fault. Domestic and foreign scholars have conducted in-depth research on the diagnosis method of the turn-to-turn short-circuit fault of the motor winding and have achieved a series of results. However, the research on the fault-tolerant control of the motor winding short-circuit fault is generally aimed at the situation of the entire winding short circuit. There are relatively few studies on the fault-tolerant control after the turn-to-turn short-circuit fault, and due to the existence of harmonic space, the formulation of the fault-tolerant control strategy is relatively difficult.

[0004] Therefore, in order to solve the above problems, it is necessary to conduct a systematic study on the fault-tolerant control strategy after the inter-turn short-circuit fault, so as to reduce the phase current of the inter-turn short-circuit fault, avoid the further spread of the fault, and ensure the torque output performance. Summary of the invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the background technology, the present invention requests to disclose a fault-tolerant control method for inter-turn short-circuit fault of an open-winding five-phase FTFSCW-IPM motor. When an inter-turn short-circuit fault is detected, the method reconstructs the topology by connecting an external resistor to reduce the fault phase current, and divides the composite fault after the topology reconstruction into an open circuit fault and an inter-turn short-circuit fault. A carrier-based fault-tolerant control method is used for the open circuit fault. A mathematical model of the open-winding five-phase motor is established for the superposition of the open circuit fault and the inter-turn short-circuit fault. The compensation amount of the controller is estimated in real time by the zero-sequence voltage and the phase current after the fault, so as to eliminate the influence of the short-circuit current on the torque.

[0006] Technical solution: The present invention discloses a turn-to-turn short-circuit fault-tolerant control method for a five-phase FTFSCW-IPM motor based on an open winding:

[0007] S1. Establish a mathematical model of an open-winding five-phase FTFSCW-IPM motor, including flux, voltage, torque and motion equations;

[0008] S2. After detecting the occurrence of an inter-turn short-circuit fault, connect an external resistor to reconstruct the drive system fault, and formulate a fault-tolerant control strategy for the reconstructed open-phase fault;

[0009] S3. For the inter-turn short-circuit fault after system reconstruction and the phase failure fault in S2, a turn-to-turn short-circuit fault-tolerant control strategy based on feedforward compensation is formulated.

[0010] Among them, in S1:

[0011] Motor stator flux equation:

[0012] ψ s =L s I s +ψ m (6)

[0013] in: Represents the total flux matrix of each phase;

[0014] represents the stator winding inductance matrix;

[0015] represents the five-phase current matrix;

[0016] represents the permanent magnet flux matrix of the rotor permanent magnet coupled in each phase, represents the electrical angle, γ is a constant of 0.4π;

[0017] Where: a ,ψ b ,ψ c ,ψ d ,ψ e ,ψ PM They are the armature winding flux and permanent magnet flux amplitude respectively; i a ,i b ,i c ,i d ,i e are the currents of each phase of the five-phase armature winding; L aa =L bb =L cc =L dd =L ee =L s is the self-inductance of each phase winding;

[0018] M xy =L m(x=a,b,c,d,e,y=a,b,c,d,e,x≠y) is the mutual inductance between the phase windings;

[0019] The mathematical model of the five-phase motor voltage in the rotating dq coordinate is:

[0020]

[0021] Where: u dq ,i dq ,= f , respectively represent the dq axis components of stator voltage, current and flux; L d ,L q represents the AC and DC axis inductance of the motor; ωe is the rotor electrical angular velocity;

[0022] The mechanical motion equation of the open-winding five-phase FTFSCW-IPM motor is:

[0023]

[0024] Where: T e is the electromagnetic torque, T l is the load torque, J is the moment of inertia, ωe is the mechanical angular velocity, and B is the friction coefficient of the drive system;

[0025] The fault-tolerant IPM torque equation becomes:

[0026]

[0027] There is no third harmonic in the motor back electromotive force of the present invention, and the salient pole effect is not obvious. To facilitate modeling and controller design, the torque equation is simplified to:

[0028]

[0029] Further, in S2: it is recorded that a phase failure occurs in the A-phase winding, and an equal-amplitude fault-tolerant control method is adopted;

[0030] After a phase failure occurs, the equal magnetic motive force principle gives

[0031]

[0032] Where: i′ x (x=B,C,D,E) is the target current after the phase failure. According to the equal amplitude constraint condition, the following equation is obtained:

[0033] i′ B = -i′ D i′ C = -i′ E (7)

[0034] The target current after a phase failure is expressed as:

[0035]

[0036] According to equation (8), the current after the phase failure is controlled, and the carrier-based fault-tolerant control strategy is adopted to achieve stable torque output;

[0037] According to formula (8), the residual phase current can be projected onto the α-β plane, γ plane and zero-sequence plane. To ensure that the electromechanical energy conversion process only occurs on the fundamental wave plane, the transformation vectors on the γ plane and the zero plane are required to be perpendicular to the vectors on the α-β plane. The Clarke inverse transformation matrix T F It is expressed as:

[0038]

[0039] According to formula (9), the Clarke transformation matrix is ​​derived as

[0040]

[0041] Since there is no electromechanical energy conversion in the γ plane and the zero plane, the Parker transformation matrix T P As shown below:

[0042]

[0043] According to equations (9)-(11), fault-tolerant control for phase failure is achieved, and stable torque output is achieved.

[0044] Furthermore, in S3:

[0045] Short circuit resistance R f Indicates the degree of insulation damage of the faulty winding; i f Represents the current of the short-circuit loop; i′ A Represents the A-phase current after connecting to the external resistor; R a1 and L a1 is the resistance and inductance of the normal part of winding A; R a2 and L a2 is the resistance and inductance of the short-circuit loop; L x (x=A,B,C,D,E) represents the self-inductance of each phase winding, L x The value is equal to L s ; Mxy (x=a1,a2,B,C,D,E; y=a1,a2,B,C,D,E, x≠y) represents the mutual inductance between the x and y windings, and the mutual inductance value is equal to L m ;e x (x=A,B,C,D,E) represents the back electromotive force of each phase winding;

[0046] When a phase failure is superimposed on a short circuit failure and the A-phase winding is connected to an external resistor, the torque equation of the motor is expressed as:

[0047]

[0048] Where: m Represents the mechanical angular velocity of the rotor, μ = N f / N represents the short-circuit turns ratio, N f is the number of turns of the short-circuit winding, N is the total number of turns of the phase winding with short-circuit fault, e f is the electromotive force of the short-circuit circuit;

[0049] Based on the phase-failure fault-tolerant control, the torque ripple optimization control strategy is re-formulated;

[0050] Use the normal phase to cancel the current 'μi f -i′ A 'Influence on torque output, considering the inter-turn short-circuit fault and topology reconstruction, the relationship between the synchronous rotating coordinate system current and the stationary coordinate system current under the inter-turn short-circuit fault condition is as follows:

[0051]

[0052] According to formula (13), the dq axis current compensation is solved as:

[0053]

[0054] After a turn-to-turn short circuit fault occurs in the A-phase winding and the topology is reconstructed, ignoring the mutual inductance between the windings, the voltage equation of the open winding five-phase motor under fault can be expressed as:

[0055]

[0056] Where p is the Laplace operator, u0 and i0 are the zero-sequence voltage and zero-sequence current respectively. According to equation (15), the voltage equation is added to obtain

[0057] 5R s i0+5L s pi0-μR s i f -μL s pi f =5u0 (16)

[0058] By Laplace transforming equation (16), we can get:

[0059]

[0060] Formula (17) can accurately estimate the current compensation amount, and the remaining four-phase target voltage is expressed as:

[0061]

[0062] Where: k xp (x=d,q,γ,0) and k xi Respectively represent the proportional and integral coefficients of the controller;

[0063] Based on the above, the entire turn-to-turn short-circuit fault torque pulsation optimization control strategy is obtained to ensure the smooth output of torque of any phase in the event of a turn-to-turn short-circuit fault.

[0064] Furthermore, it also includes S4: using the MATLAB / Simulink simulation platform to build a corresponding control simulation model to verify the effectiveness of the control strategy in eliminating the torque pulsation caused by the inter-turn short circuit fault of the motor.

[0065] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0066] The optimized fault-tolerant control strategy can effectively reduce the short-circuit current of the fault phase by connecting the fault phase to an external resistor, avoid further propagation of the fault, and ensure the smooth and reliable operation of the open-winding five-phase motor drive system.

[0067] This optimization control strategy eliminates the influence of inter-turn short-circuit fault on torque output by means of feedforward compensation. Since the feedforward compensation amount is related to the short-circuit loop current and the short-circuit turns ratio and cannot be directly measured, the present invention estimates the current to be compensated in real time through the zero-sequence voltage and the remaining four-phase stator current;

[0068] This optimization control strategy can effectively suppress harmonic current and ensure stable torque output when short-circuit turns ratio occurs and load changes.

[0069] The fault-tolerant control method is simple, efficient, easy to operate in practice, and helps to transform theoretical innovations into engineering practice and practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is the fault-tolerant control block diagram of the open-winding five-phase FTFSCW-IPM motor with inter-turn short-circuit fault;

[0071] Figure 2 The winding structure of the open-winding five-phase FTFSCW-IPM motor after a turn-to-turn short-circuit fault occurs;

[0072] Figure 3 Currents in stationary and rotating coordinate systems;

[0073] Figure 4 Phase current and torque response diagram during the process from normal to fault-tolerant control;

[0074] Figure 5Phase current and torque response diagram when load changes during fault-tolerant control;

[0075] Figure 6 Phase current and torque response diagram when short-circuit turns ratio during fault-tolerant control;

[0076] Figure 7 The amount of compensation when the short-circuit turns ratio changes. DETAILED DESCRIPTION

[0077] The following is a detailed description in conjunction with the specific implementation methods and the accompanying drawings.

[0078] like Figure 1 The open-winding five-phase FTFSCW-IPM motor turn-to-turn short-circuit fault tolerance control method shown includes the following steps:

[0079] S1. Establish a mathematical model of an open-winding five-phase FTFSCW-IPM motor, including flux, voltage, torque and motion equations;

[0080] S2. After detecting the occurrence of an inter-turn short-circuit fault, connect an external resistor to reconstruct the drive system fault, and formulate a fault-tolerant control strategy for the reconstructed open-phase fault;

[0081] S3, formulate a turn-to-turn short-circuit fault-tolerant control strategy based on feedforward compensation for the turn-to-turn short-circuit fault after system reconstruction combined with the phase failure fault in S2;

[0082] S4. Validity verification.

[0083] like Figure 2-7 As shown, the specific steps are as follows.

[0084] S1. Establish the mathematical model of the open-winding five-phase FTFSCW-IPM motor including flux, voltage, torque and motion equations.

[0085] Motor stator flux equation:

[0086] ψ s =L s I s +ψ m (11)

[0087] in: Represents the total flux matrix of each phase;

[0088] represents the stator winding inductance matrix;

[0089] represents the five-phase current matrix;

[0090] represents the permanent magnet flux matrix of the rotor permanent magnet coupled in each phase, Represents the electrical angle, γ is a constant 0.4π.

[0091] Where: a ,ψ b ,ψ c ,ψ d ,ψ e ,ψ PM They are the armature winding flux and permanent magnet flux amplitude respectively; i a ,i b ,i c ,i d ,i e , are the currents of each phase of the five-phase armature winding; L aa =L bb =L cc =L dd =L ee =L s is the self-inductance of each phase winding,

[0092] M xy =L m (x=a,b,c,d,e,y=a,b,c,d,e,x≠y) is the mutual inductance between the phase windings.

[0093] The mathematical model of the open-winding five-phase motor voltage in the rotating dq coordinate is:

[0094]

[0095] Where: u dq ,i dq ,ψ f , respectively represent the dq axis components of stator voltage, current and flux; L d ,L q It represents the AC and DC axis inductance of the motor; ωe is the rotor electrical angular velocity.

[0096] The mechanical motion equation of the open-winding five-phase FTFSCW-IPM motor is:

[0097]

[0098] Where: Tl is the load torque, J is the moment of inertia, ωe is the mechanical angular velocity, and B is the friction coefficient of the drive system.

[0099] The fault-tolerant IPM torque equation becomes:

[0100]

[0101] The open-winding five-phase FTFSCW-IPM motor corresponding to the present invention does not have a third harmonic in the back EMF, and the salient pole effect is not obvious. To facilitate modeling and controller design, the torque equation is simplified to:

[0102]

[0103] S2. After detecting the occurrence of an inter-turn short-circuit fault, connect an external resistor to reconstruct the drive system fault, and formulate a fault-tolerant control strategy for the reconstructed phase failure fault.

[0104] After a turn-to-turn short-circuit fault occurs in an open-winding five-phase permanent magnet fault-tolerant motor system, the current of the fault phase can be significantly reduced by disconnecting the short-circuited phase and connecting it to an external resistor. In this case, the fault under this topology can be equivalent to a phase failure and a turn-to-turn short-circuit fault, and corresponding fault-tolerant control strategies can be formulated respectively. The phase failure fault-tolerant control strategy is described in detail as follows:

[0105] Taking the A-phase winding as an example, when only the A-phase winding in the motor is considered to have a phase failure, the current of the remaining four-phase windings can be controlled to achieve smooth torque output. The principle of phase failure fault-tolerant control is to ensure that the magnetic motive force remains unchanged before and after the phase failure, which requires that the amplitude and phase of the remaining four-phase winding currents be adjusted accordingly to meet this requirement. Usually, due to different constraints, two typical fault-tolerant current optimization methods emerge. The first is the current equal amplitude method, and the second is the current minimum copper loss method. In order to limit the current amplitude, this article adopts the equal amplitude fault-tolerant control method. After a phase failure occurs, the principle of equal magnetic motive force can be used to obtain:

[0106]

[0107] Where: i′ x (x=B,C,D,E) is the target current after the phase failure. According to the equal amplitude constraint, the following equation can be obtained:

[0108] i′ B = -i′ D i′ C = -i′ E (7)

[0109] Therefore, the target current after a phase failure can be expressed as:

[0110]

[0111] It can be seen from formula (8) that the amplitude of the phase current after the fault is 1.382 times that of the normal state. When the current after the phase failure is controlled according to formula (8), the torque can be output smoothly. Usually, the target current can be used as a reference quantity, and the fault-tolerant control current can be obtained by using the hysteresis controller. However, the switching frequency of the hysteresis control is not fixed, and the switching frequency is large when the hysteresis loop width is narrow, and the corresponding switching loss increases. Therefore, in order to overcome the shortcomings of hysteresis control and ensure that the current relationship satisfies formula (8), this paper adopts a carrier-based fault-tolerant control strategy, the key of which is to obtain the coordinate transformation matrix after the fault.

[0112] According to equation (8), the residual phase current can be projected onto the α-β plane, γ plane and zero-sequence plane. To ensure that the electromechanical energy conversion process occurs only on the fundamental wave plane, the transformation vectors on the γ plane and the zero plane are required to be perpendicular to the vectors on the α-β plane. In this case, the Clarke inverse transformation matrix T F Finally it can be expressed as:

[0113]

[0114] According to formula (4), the Clarke transformation matrix can be derived as:

[0115]

[0116] Since there is no electromechanical energy conversion in the γ plane and the zero plane, the Parker transformation matrix T P It can be as follows:

[0117]

[0118] According to equations (9)-(11), fault-tolerant control for phase failure can be achieved, and stable torque output can be realized.

[0119] S3, formulate a turn-to-turn short-circuit fault-tolerant control strategy based on feedforward compensation for the turn-to-turn short-circuit fault after system reconstruction combined with the phase failure fault in S2;

[0120] Taking the turn-to-turn short circuit fault of phase A as an example, when the turn-to-turn short circuit fault is detected, Figure 2 As shown, the faulty phase is actively disconnected and connected to an external resistor R through a switch S, which is equivalent to the superposition of a phase failure and a turn-to-turn short circuit failure. The selection of the external resistor should be considered based on the magnitude of the back electromotive force and the magnitude of the current amplitude of phase A to be limited. Figure 2 In the short circuit resistance R f Indicates the degree of insulation damage of the faulty winding, i f Represents the current of the short-circuit loop; i′ A Represents the A-phase current after connecting to the external resistor; R a1 and L a1is the resistance and inductance of the normal part of winding A; R a2 and L a2 is the resistance and inductance of the short-circuit loop; L x (x=A,B,C,D,E) represents the self-inductance of each phase winding, L x The value is equal to L s ; Mxy (x=a1,a2,B,C,D,E; y=a1,a2,B,C,D,E, x≠y) represents the mutual inductance between the x and y windings, and the mutual inductance value is equal to L m ;e x (x=A, B, C, D, E) represents the back electromotive force of each phase winding.

[0121] When a phase failure is superimposed on a short circuit failure and the A phase winding is connected to an external resistor, Figure 2 It can be seen that the back electromotive force of phase A winding will continue to provide electrical energy for the short-circuit loop. In this case, the torque equation of the motor can be expressed as:

[0122]

[0123] Where: m Indicates the mechanical angular velocity of the rotor, μ = N f / N represents the short-circuit turns ratio, N f is the number of turns of the short-circuit winding, and N is the total number of turns of the phase winding with short-circuit fault between turns. f is the electromotive force of the short-circuit circuit. From (12), we can see that e A and 'μi f -i′ A The product term of ' will inevitably bring torque pulsation to the system and reduce the output performance of the drive system. Therefore, based on the phase-failure fault-tolerant control, it is necessary to re-formulate the torque pulsation optimization control strategy.

[0124] Considering the current 'μi f -i′ A 'It cannot be directly measured and controlled. In order to eliminate its influence on the torque output, it is necessary to use the remaining four normal phases to offset it. Considering the inter-turn short-circuit fault and topology reconstruction, the relationship between the current in the stationary coordinate system and the current in the rotating coordinate system is as follows: Figure 3 As shown in (b). Since the projection of phase A current on the α axis is Figure 3 (a) Compared with the α-axis current, it increases by 0.4 (μi f -i′ A )'. In the figure, i cd and i cq are the compensation amounts of dq axis current respectively.

[0125] To obtain the compensation current, according to Figure 3(b), the relationship between the synchronous rotating coordinate system current and the stationary coordinate system current under the condition of inter-turn short circuit fault can be obtained as follows:

[0126]

[0127] According to formula (13), the dq axis current compensation can be solved as:

[0128]

[0129] It can be seen from formula (14) that the compensation amount of dq axis current is related to the short-circuit turns ratio, short-circuit current, A phase current and rotor position. Since the short-circuit current and short-circuit turns ratio cannot be measured directly, the current cannot be compensated directly. After the A phase winding has an inter-turn short-circuit fault and the topology is reconstructed, ignoring the mutual inductance between the windings, the voltage equation of the open winding five-phase motor under fault can be expressed as:

[0130]

[0131] Where p is the Laplace operator, u0 and i0 are the zero-sequence voltage and zero-sequence current respectively. According to equation (15), adding the voltage equations can be obtained:

[0132] 5R s i0+5L s pi0-μR s i f -μL s pi f =5u0 (16)

[0133] By performing Laplace transformation on equation (16), we can obtain:

[0134]

[0135] From formula (12), we can see that 'μi f -i′ A 'Real-time estimation can be performed through the zero-sequence voltage and the remaining four-phase normal phase current. The zero-sequence voltage can be obtained from the phase voltage of the five-phase winding, and the A-phase voltage can be obtained based on the current i' flowing through the external resistor R A The voltage of the remaining four normal phases can be obtained by calculating the duty cycle of each phase. Even if the short-circuit turns ratio and short-circuit current change, equation (17) can still accurately estimate the current compensation amount. The target voltage of the remaining four phases can be expressed as:

[0136]

[0137] Where: k xp (x=d,q,γ,0) and k xiRepresent the proportional and integral coefficients of the controller respectively. The block diagram of the entire turn-to-turn short-circuit fault torque ripple optimization control strategy is as follows: Figure 5 Compared with normal operation, the dq axis of this fault-tolerant control strategy increases the compensation current. In the current harmonic space, the harmonic current to be controlled is determined by i d3 、i q3 becomes i γ Based on this control block diagram, the torque of any phase can be output smoothly when there is a turn-to-turn short circuit fault.

[0138] S4. In order to verify the effectiveness of the fault-tolerant control strategy after the inter-turn short-circuit fault proposed in the present invention, we use the MATLAB / Simulink simulation platform to build a corresponding control simulation model. During the simulation, the motor speed is 600r / min, the torque is 6N·m, and the external resistance during topology reconstruction is selected as 150Ω to ensure that the short-circuit phase current is within 1A. The simulation results are shown in Figure 2. Figures 4 to 7 shown.

[0139] Figure 4 (a)-(b) are the phase current waveforms and torque waveforms of fault-tolerant control when a turn-to-turn short-circuit fault occurs. The short-circuit turn ratio μ=0.577, and the short-circuit resistance R f =2Ω. At t=0.08s, a turn-to-turn short circuit fault occurs, and the A-phase winding is actively disconnected. The current waveform is distorted, and the torque pulsates greatly. At t=0.12s, the A-phase winding is connected to an external resistor, and the torque pulsation optimization control strategy is adopted. It can be seen that after t=0.12s, the torque pulsation is effectively suppressed and the current waveform returns to a sinusoidal state. Due to the external resistor, the A-phase winding current i′ A The current amplitude is small, which can avoid further spread of the fault.

[0140] Figure 5 (a)-(b) are the simulation results under the condition of fault-tolerant control with time-varying load. At t=0.08s, the motor has a turn-to-turn short circuit fault and the fault-tolerant control strategy is applied at the same time. It can be seen that the torque does not change significantly during the fault-tolerant control switching process, which is similar to the normal operating torque; after t=0.12s, the load changes from 3N·m to 7N·m. During this process, the current amplitude increases and the sinusoidality is good. The torque switching process is smooth, which shows the effectiveness of the fault-tolerant control strategy.

[0141] Figure 6 (a)-(b) are the simulation results when the inter-turn short-circuit turns ratio changes during the fault-tolerant operation process. After t=0.12s, the short-circuit turns ratio changes from 0.18 to 0.577. It can be seen that after the short-circuit turns ratio changes, the motor phase current increases, while the torque continues to maintain a stable output; Figure 7The fitting between the estimated value and the actual value of the current compensation amount during the change of the short-circuit turns ratio is studied. It can be seen that the current compensation amount can still be accurately estimated when the short-circuit turns ratio changes.

[0142] These data demonstrate the effectiveness of the turn-to-turn short-circuit fault-tolerant control method based on the open-winding five-phase FTFSCW-IPM motor proposed in this invention.

Claims

1. A five-phase FTFSCW-IPM motor turn-to-turn short-circuit fault tolerance control method based on open winding, characterized in that: The following steps are involved: S1. Establish a mathematical model of an open-winding five-phase FTFSCW-IPM motor, including flux, voltage, torque and motion equations; S2. After detecting the occurrence of an inter-turn short-circuit fault, connect an external resistor to reconstruct the drive system fault, and formulate a fault-tolerant control strategy for the reconstructed open-phase fault; S3. For the inter-turn short-circuit fault after system reconstruction and the phase failure fault in S2, a turn-to-turn short-circuit fault-tolerant control strategy based on feedforward compensation is formulated.

2. The turn-to-turn short-circuit fault-tolerant control method based on an open-winding five-phase FTFSCW-IPM motor according to claim 1 is characterized in that: In S1: Motor stator flux equation: ψ s =L s I s +ψ m (1) Among them: Represents the total flux matrix of each phase; represents the stator winding inductance matrix; represents the five-phase current matrix; represents the permanent magnet flux matrix of the rotor permanent magnet coupled in each phase, represents the electrical angle, γ is a constant of 0.4π; Where: a ,ψ b ,ψ c ,ψ d ,ψ e ,ψ PM They are the armature winding flux and permanent magnet flux amplitude respectively; i a ,i b ,i c ,i d ,i e are the currents of each phase of the five-phase armature winding; L aa =L bb =L cc =L dd =L ee =L s is the self-inductance of each phase winding; M xy =L m (x=a,b,c,d,e,y=a,b,c,d,e,x≠y) is the mutual inductance between the phase windings; The mathematical model of the five-phase motor voltage in the rotating dq coordinate is: Where: u dq ,i dq ,ψ f , respectively represent the dq axis components of stator voltage, current and flux; L d ,L q represents the AC and DC axis inductance of the motor; ωe is the rotor electrical angular velocity; The mechanical motion equation of the open-winding five-phase FTFSCW-IPM motor is: Where: T e is the electromagnetic torque, T l is the load torque, J is the moment of inertia, ωe is the mechanical angular velocity, and B is the friction coefficient of the drive system; The fault-tolerant IPM torque equation becomes: There is no third harmonic in the motor back electromotive force of the present invention, and the salient pole effect is not obvious. To facilitate modeling and controller design, the torque equation is simplified to:

3. The turn-to-turn short-circuit fault tolerance control method based on the open-winding five-phase FTFSCW-IPM motor according to claim 2 is characterized in that: In S2: when a phase failure occurs in the A-phase winding, an equal-amplitude fault-tolerant control method is adopted; After a phase failure occurs, the equal magnetic motive force principle gives Where: i′ x (x=B,C,D,E) is the target current after the phase failure. According to the equal amplitude constraint condition, the following equation is obtained: i′ B =-i′ D i′ C =-i′ E (7) The target current after a phase failure is expressed as: According to equation (8), the current after the phase failure is controlled, and the carrier-based fault-tolerant control strategy is adopted to achieve stable torque output; According to formula (8), the residual phase current can be projected onto the α-β plane, γ plane and zero-sequence plane. To ensure that the electromechanical energy conversion process only occurs on the fundamental wave plane, the transformation vectors on the γ plane and the zero plane are required to be perpendicular to the vectors on the α-β plane. The Clarke inverse transformation matrix T F It is expressed as: According to formula (9), the Clarke transformation matrix is ​​derived as Since there is no electromechanical energy conversion in the γ plane and the zero plane, the Parker transformation matrix T P As shown below: According to equations (9)-(11), fault-tolerant control for phase failure is achieved, and stable torque output is achieved.

4. The turn-to-turn short-circuit fault tolerance control method based on the open-winding five-phase FTFSCW-IPM motor according to claim 3 is characterized in that: In S3: Short circuit resistance R f Indicates the degree of insulation damage of the faulty winding; i f Represents the current of the short-circuit loop; i′ A Represents the A-phase current after connecting to the external resistor; R a1 and L a1 is the resistance and inductance of the normal part of winding A; R a2 and L a2 is the resistance and inductance of the short-circuit loop; L x (x=A,B,C,D,E) represents the self-inductance of each phase winding, L x The value is equal to L s ; Mxy (x=a1,a2,B,C,D,E; y=a1,a2,B,C,D,E, x≠y) represents the mutual inductance between the x and y windings, and the mutual inductance value is equal to L m ;e x (x=A,B,C,D,E) represents the back electromotive force of each phase winding; When a phase failure is superimposed on a short circuit failure and the A-phase winding is connected to an external resistor, the torque equation of the motor is expressed as: Where: m Indicates the mechanical angular velocity of the rotor, μ = N f / N represents the short-circuit turns ratio, N f is the number of turns of the short-circuit winding, N is the total number of turns of the phase winding with short-circuit fault, e f is the electromotive force of the short-circuit circuit; Based on the phase-failure fault-tolerant control, the torque ripple optimization control strategy is re-formulated; Use the normal phase to cancel the current 'μi f -i′ A 'Influence on torque output, considering the inter-turn short-circuit fault and topology reconstruction, the relationship between the synchronous rotating coordinate system current and the stationary coordinate system current under the inter-turn short-circuit fault condition is as follows: According to formula (13), the dq axis current compensation is solved as: After a turn-to-turn short circuit fault occurs in the A-phase winding and the topology is reconstructed, ignoring the mutual inductance between the windings, the voltage equation of the open winding five-phase motor under fault can be expressed as: Where; Where p is the Laplace operator, u0 and i0 are the zero-sequence voltage and zero-sequence current respectively. According to equation (15), the voltage equation is added to obtain 5R s i0+5L s pi0-μR s i f -μL s pi f =5u0 (16) By Laplace transforming equation (16), we can get: Formula (17) can accurately estimate the current compensation amount, and the remaining four-phase target voltage is expressed as: Where: k xp (x=d,q,γ,0) and k xi Respectively represent the proportional and integral coefficients of the controller; Based on the above, the entire turn-to-turn short-circuit fault torque pulsation optimization control strategy is obtained to ensure the smooth output of torque of any phase in the event of a turn-to-turn short-circuit fault.

5. The turn-to-turn short-circuit fault tolerance control method based on open-winding five-phase FTFSCW-IPM motor according to claim 1 is characterized in that: It also includes S4: using the MATLAB / Simulink simulation platform to build a corresponding control simulation model to verify the effectiveness of the control strategy in eliminating the torque pulsation caused by the inter-turn short circuit fault of the motor.

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