A dual-redundancy permanent magnet synchronous motor single-phase circuit fault free diagnosis self-fault-tolerant control method

Abstract

This invention belongs to the field of permanent magnet synchronous motor control and proposes a diagnostic-free, self-fault-tolerant control method for single-phase open-circuit faults in dual-redundant permanent magnet synchronous motors. Based on the vector space decoupling transformation of dual-redundant permanent magnet synchronous motors, this method constructs a unified control model applicable to both "normal phases" and "arbitrary single-phase open-circuit faults" by improving the xy subspace current control method. In the absence of faults, this method allows the motor to operate in a balanced power state across all phases. When a single-phase open-circuit fault occurs, this method can accurately disconnect the three-phase winding containing the faulty phase without any fault diagnosis, achieving fault-tolerant operation. Therefore, compared to traditional fault-tolerant control methods, this method avoids the risk of misdiagnosis and the fault operation process before diagnostic results are obtained, thereby improving reliability. Furthermore, fault-tolerant operation does not require refactoring the control structure or adjusting the reference current, simplifying the control process.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motor control, specifically relating to a fault-tolerant control method under motor phase loss faults. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in industrial fields due to their advantages such as high efficiency, high power factor, and high power density. However, traditional single-redundant PMSM systems lack hardware backup and cannot effectively tolerate faults such as phase loss, making them unsuitable for high-reliability applications such as aerospace and ship propulsion. In contrast, dual-redundant PMSMs, through phase redundancy design, can maintain normal system operation after a phase loss fault by appropriately adjusting the control strategy, thereby enhancing reliability.

[0003] Dual-redundant permanent magnet synchronous motors contain two independent sets of Y-connected three-phase windings, each designed according to the motor's rated voltage, current, and power rating. Under normal conditions, both sets of three-phase windings transmit power simultaneously (each operating at 50% of rated power). When a phase of the motor experiences an open-circuit fault, the three-phase winding containing the faulty phase can be disconnected. The motor continues to transmit power using a single, fully healthy three-phase winding (operating at rated power). However, although this method can effectively compensate for a phase loss fault, fault diagnosis remains a crucial prerequisite for fault-tolerant operation. Therefore, existing fault-tolerant control methods have the following problems:

[0004] (1) Before the specific fault diagnosis results are fully obtained, the fault operation status of the motor will continue to have an adverse effect on the system and may cause secondary damage.

[0005] (2) The risk of misdiagnosis of faults also reduces the reliability of fault-tolerant operation to some extent. Summary of the Invention

[0006] To address the phase-loss fault problem in dual-redundant permanent magnet synchronous motors, researching a control method that can achieve effective fault tolerance without fault diagnosis is of great significance for improving the reliability of the drive system. Therefore, this paper presents a self-fault-tolerant control method for single-phase circuit interruption in dual-redundant permanent magnet synchronous motors, specifically:

[0007] The control process is applicable to both situations where a phase loss fault has not occurred and situations where a phase loss fault has occurred, and is not limited by which phase the phase loss fault occurs. The control process is executed consistently, thereby eliminating the reliance on fault diagnosis for the control process. The control process includes the following steps:

[0008] Step 1: In each control cycle, the current of each phase of the motor is collected in real time, and the αβ subspace current i is obtained through vector space decoupling transformation. α iβ and the xy subspace current i x i y ;

[0009] Step 2: Perform a Park transformation on the αβ subspace current to obtain the dq subspace current i. d i q ;

[0010] Step 3: Perform closed-loop control on the dq subspace current to obtain the dq subspace reference voltage value u. d ref u q ref ;

[0011] Step 4: Decompose the xy subspace current into positive and negative sequence components to obtain the positive sequence current component i in the xy subspace. x_p i y_p and the negative sequence current component i in the xy subspace x_n i y_n ;

[0012] Step 5: For the xy subspace current, perform closed-loop control on the positive sequence current component to obtain the xy subspace positive sequence reference voltage value u. x_p ref u y_p ref Directly set the negative sequence reference voltage value u corresponding to the negative sequence current component. x_n ref =0、u y_n ref =0; Based on this, the overall reference voltage value u of the xy subspace is obtained. x ref u y ref ;

[0013] Step 6: Based on the dq subspace reference voltage values ​​obtained in Step 3 and the xy subspace reference voltage values ​​obtained in Step 5, perform space vector pulse width modulation to obtain the motor's phase drive signals S. A1 S B1 S C1 S A2 S B2 S C2 This completes the entire control process.

[0014] Step 1 includes:

[0015] For each phase current i in each control cycle A1 ~i C2 After data acquisition, the αβ subspace current i is obtained through the vector space decoupling transformation process shown in the following equation. αi β and the xy subspace current i x i y :

[0016] .

[0017] Step 2 includes:

[0018] The αβ subspace current i obtained by the vector space decoupling transformation α i β The dq subspace current i is obtained from the Park transformation process shown in the following equation. d i q :

[0019] ,

[0020] In the formula, θ e The electric angle of the motor rotor.

[0021] Step 3 includes:

[0022] Step 301: Set the dq subspace current i d The reference value is 0A, and the current i in the dq subspace is set. q The reference value is the outer loop control output value I of the rotational speed;

[0023] Step 302: Perform closed-loop control on the dq subspace current. The closed-loop controller adopts a proportional-integral resonant structure with a resonant frequency of twice the fundamental frequency. The transfer function of the closed-loop controller is G. PIR_(dq) (s) can be specifically expressed as:

[0024] ,

[0025] In the formula, K p_(dq) K is the proportionality coefficient. i_(dq) K is the integral coefficient. r_(dq) ω is the resonance coefficient. c_(dq) ω is the resonant bandwidth. e The fundamental frequency electrical angular velocity;

[0026] Step 303: Use the output value of the dq subspace current closed-loop controller as the dq subspace reference voltage value u. d ref u q ref .

[0027] Step 4 includes:

[0028] Step 401: Convert the x-axis component i of the xy subspace current x Shifting 90° to the right yields the x-axis phase-shifted current i.x_shift_-90° Simultaneously, the y-axis component i of the current in the xy subspace is... y Shifting 90° to the left yields the y-axis phase-shifted current i. y_shift_+90° ;

[0029] Step 402: Obtain the positive-sequence current component i in the decomposed xy subspace using the following two equations. x_p i y_p and the negative sequence current component i in the xy subspace x_n i y_n :

[0030] ,

[0031] .

[0032] Step 5 includes:

[0033] Step 501: For the positive sequence current component i in the xy subspace x_p i y_p This is incorporated into closed-loop control, and a corresponding current reference value i is set. x_p ref i y_p ref for:

[0034] ;

[0035] Step 502: When performing closed-loop control on the positive sequence current component of the xy subspace, the closed-loop controller adopts a proportional resonant structure, and the closed-loop controller transfer function G... PR_(xy_p) (s) can be specifically expressed as:

[0036] ,

[0037] In the formula, K p_(xy_p) K is the proportionality coefficient. r_(xy_p) ω is the resonance coefficient. c_(xy_p) The resonant bandwidth;

[0038] Step 503: When performing closed-loop control on the positive sequence current component of the xy subspace, the output value of the closed-loop controller for the positive sequence current component of the xy subspace is used as the positive sequence reference voltage value u of the xy subspace. x_p ref u y_p ref ;

[0039] Step 504: For the negative sequence current component i in the xy subspace x_n i y_n This excludes it from closed-loop control, and directly sets the negative sequence reference voltage value u in the xy subspace. x_nref =0、u y_n ref =0;

[0040] Step 505: By adding the positive-sequence reference voltage value of the xy subspace obtained in step 503 to the negative-sequence reference voltage value of the xy subspace set in step 504, the overall reference voltage value u of the xy subspace is obtained. x ref u y ref ,Right now:

[0041] .

[0042] Step 6 includes:

[0043] Step 601: Apply the dq subspace reference voltage value u obtained in step 3. d ref u q ref Performing the inverse Park transform shown in the following equation yields the reference voltage value u in the αβ subspace. α ref u β ref :

[0044] ;

[0045] Step 602: Based on the classical vector space decoupling model, select a synthesizable αβ subspace reference voltage value u. α ref u β ref and xy subspace reference voltage value u x ref u y ref The basic voltage vector is obtained, and the driving signal S of each phase of the motor is derived by calculating the duration of action of each vector. A1 S B1 S C1 S A2 S B2 S C2 .

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) Based on the control method proposed in this invention, the system can achieve both control under the condition of "normal phases" and fault-tolerant control under the condition of "any single-phase circuit failure" under the unified control structure and unified reference current before and after phase failure. Therefore, the realization of fault-tolerant operation does not depend on any fault diagnosis, thus effectively avoiding the risk of misdiagnosis and the fault operation process before the diagnosis result is obtained.

[0048] (2) Since fault-tolerant operation does not require reconfiguration of the control structure and adjustment of the reference current, the control process is simplified to a certain extent. Attached Figure Description

[0049] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0050] Figure 1 A schematic diagram of the basic structure of a dual-redundant permanent magnet synchronous motor drive system based on a single-phase circuit-free, self-fault-tolerant control method for dual-redundant permanent magnet synchronous motors.

[0051] Figure 2 A diagnostic-free, fault-tolerant control method for single-phase circuit interruption of a dual-redundant permanent magnet synchronous motor is presented, targeting the current control mode of the xy subspace.

[0052] Figure 3 The overall control block diagram is shown for a single-phase circuit-free, self-fault-tolerant control method for dual-redundant permanent magnet synchronous motors.

[0053] Figure 4 The dq subspace current waveform diagram is shown for a single-phase circuit-free, self-fault-tolerant control method for a dual-redundant permanent magnet synchronous motor.

[0054] Figure 5 The waveforms of motor speed and electromagnetic torque are shown for a single-phase circuit-free, self-fault-tolerant control method for a dual-redundant permanent magnet synchronous motor.

[0055] Figure 6 The waveform of the positive sequence current component in the xy subspace of a single-phase circuit-free, self-fault-tolerant control method for a dual-redundant permanent magnet synchronous motor is shown.

[0056] Figure 7 The waveform of the negative sequence current component in the xy subspace of a single-phase circuit-free, self-fault-tolerant control method for a dual-redundant permanent magnet synchronous motor is shown.

[0057] Figure 8 The current waveforms of each phase are shown in the diagram for a single-phase circuit-free, self-fault-tolerant control method for a dual-redundant permanent magnet synchronous motor. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0059] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0060] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0061] Example 1

[0062] Figure 1 This paper demonstrates the basic structure of a dual-redundant permanent magnet synchronous motor drive system. The motor comprises two sets of Y-connected three-phase windings (A1B1C1 winding and A2B2C2 winding), spatially separated by 30°, with their neutral points O1 and O2 isolated. Each set of three-phase windings is controlled by a separate three-phase inverter. The dual-redundant structure increases the system's fault tolerance to phase loss faults. However, this structure also introduces significant coupling between the different three-phase windings, increasing the analysis complexity. Therefore, a modeling and control method based on vector space decoupling transformation is widely used. This method effectively eliminates the influence of mutual inductance between different three-phase windings on the control process. Through vector space decoupling transformation, the voltage, current, and other variables of each phase of the motor are transformed into two mutually orthogonal subspaces: the αβ subspace and the xy subspace. Figure 1 The dual-redundant permanent magnet synchronous motor with a 30° phase shift in the dual Y region is shown in equation (1) as follows:

[0063] ;

[0064] In the formula, i A1 i B1 i C1 For the phase currents of the first set of three-phase windings, i A2 i B2 i C2 For the phase currents of the second set of three-phase windings, i α and i β Let i be the currents on the two orthogonal axes (α-axis and β-axis) of the αβ subspace, respectively. x and i y These are the currents on the two orthogonal axes (x-axis and y-axis) of the xy subspace, respectively.

[0065] Generally, the αβ subspace current is further subjected to the Park transformation to obtain the dq subspace current. The corresponding transformation process is shown in equation (2):

[0066] ;

[0067] In the formula, i d and i q Let θ be the current along the two orthogonal axes (d-axis and q-axis) of the dq subspace, respectively. e The electric angle of the motor rotor.

[0068] As can be seen from equations (1) and (2), by controlling the dq subspace current and xy subspace current under the vector space decoupling model, the effective control of the current of each phase of the motor can be indirectly achieved.

[0069] Under the vector space decoupling model, the electromagnetic torque T of the dual-redundant permanent magnet synchronous motor is... e The expression for is shown in equation (3):

[0070] ;

[0071] In the formula, n p ψ is the number of pole pairs of the motor. f For permanent magnet flux linkage, L d and L q These are the d-axis and q-axis inductances of the dq subspace, respectively.

[0072] Equation (3) shows the electromagnetic torque expression, which holds true both before and after phase loss. Therefore, to maintain a constant electromagnetic torque before and after phase loss, the dq subspace current after phase loss should be the same as before phase loss. For surface-mounted permanent magnet synchronous motors (L... d =L q The general expression for the ideal current in the dq subspace can be represented by equation (4):

[0073] ;

[0074] When a dual-redundant permanent magnet synchronous motor has no phase-loss fault, the current magnitudes of each phase should be balanced. Under this condition, when the control method shown in equation (4) is adopted, the ideal current i of each phase of the motor can be obtained from equations (1) and (2). A1_Normal ~i C2_Normal for:

[0075] ;

[0076] When a phase of a dual-redundant permanent magnet synchronous motor experiences an open-circuit fault, the three-phase winding containing the faulty phase should be disconnected, and the motor will rely on the remaining set of healthy three-phase windings for power output. To ensure constant output power before and after the phase disconnection, the current in the healthy three-phase windings should be increased to twice the value before the open-circuit fault. In other words, if the expression for each phase current under normal conditions is given by equation (5), then the ideal fault-tolerant current (ii) of each phase after an open-circuit fault occurs in a phase of the first set of three-phase windings... A1_FTC1 ~i C2_FTC1 It can be expressed by equation (6):

[0077] ;

[0078] Similarly, if a phase-loss fault occurs in the second set of three-phase windings, then the ideal fault-tolerant current (i) of each phase... A1_FTC2 ~i C2_FTC2 It can be expressed by equation (7):

[0079] ;

[0080] Based on equations (1) and (5), under normal conditions for each phase, the ideal current in the xy subspace of the vector space decoupling model is:

[0081] ;

[0082] Based on equations (1) and (6), it can be seen that when a phase of the first three-phase winding is disconnected, the ideal fault-tolerant current in the xy subspace of the vector space decoupling model is:

[0083] ;

[0084] Based on equations (1) and (7), it can be seen that when a phase of the second three-phase winding is disconnected, the ideal fault-tolerant current in the xy subspace of the vector space decoupling model is:

[0085] ;

[0086] By comparing equations (8), (9), and (10), it can be seen that the ideal current form of the xy subspace is not uniform under normal conditions and under different phase loss conditions. In other words, traditional fault-tolerant control methods rely on reliable fault diagnosis results to provide a reasonable xy subspace reference current, thereby achieving operation based on the effect shown in equation (5) before phase loss and fault-tolerant operation based on the effect shown in equation (6) or (7) after phase loss.

[0087] In contrast, this invention provides a phase loss self-fault-tolerant control method that does not rely on any fault diagnosis results. This method can achieve both operation based on the effect shown in equation (5) before phase loss and fault-tolerant operation based on the effect shown in equation (6) or equation (7) after phase loss, under a unified control structure and reference current before and after phase loss.

[0088] First, based on the symmetrical component method, the positive sequence component (i) of the ideal fault-tolerant current in the xy subspace after a phase of the first set of three-phase windings is disconnected, as shown in equation (9), can be extracted. x_p i y_p ) and negative order components (i x_n i y_n ), as shown in equations (11) and (12) respectively:

[0089] ;

[0090] ;

[0091] Similarly, equations (13) and (14) respectively give the positive-sequence and negative-sequence components of the ideal fault-tolerant current in the xy subspace after a phase of the second three-phase winding is disconnected, as shown in equation (10):

[0092] ;

[0093] ;

[0094] By comparing equations (11), (12), (13), and (14), it can be seen that when a phase-loss fault is located in a three-phase winding of a different set, the ideal fault-tolerant current in the xy subspace differs only in its negative-sequence component, while the positive-sequence component is completely consistent—both are 0A. Furthermore, under normal conditions for each phase, since the ideal current in the xy subspace is 0A (equation (8)), both the positive-sequence and negative-sequence components of the ideal current in the xy subspace are also 0A. In other words, regardless of whether a phase-loss fault occurs, and regardless of which phase the fault occurs in, the positive-sequence component of the ideal current in the xy subspace is always 0A. By fully utilizing the above characteristics, this invention proposes a novel control method that includes only the positive-sequence current component of the xy subspace in the closed-loop control, while excluding the negative-sequence current component from the closed-loop control, such as... Figure 2 As shown. The following is for... Figure 2 Further explanation of the control method shown.

[0095] (1) Decomposition of positive and negative sequence current components

[0096] To decompose the positive and negative sequence components of the xy subspace current in each control cycle, we can first decompose the x-axis component i of the xy subspace current. x Shifting 90° to the right yields the x-axis phase-shifted current i. x_shift_-90° Simultaneously, the y-axis component i of the current in the xy subspace is... y Shifting 90° to the left yields the y-axis phase-shifted current i. y_shift_+90° Based on this, the positive-sequence current component i in the decomposed xy subspace can be obtained through equations (15) and (16). x_p iy_p and the negative sequence current component i in the xy subspace x_n i y_n :

[0097] ;

[0098] ;

[0099] (2) Setting method for closed-loop control reference value of positive sequence current component

[0100] As the foregoing analysis shows, the ideal positive-sequence current component in the xy subspace is 0A before the phase loss and after any single-phase circuit failure. Therefore, Figure 2 The reference current (i) for the positive sequence current component closed-loop control is shown. x_p ref i y_p ref Set to:

[0101] ;

[0102] (3) Structural configuration of the positive sequence current component closed-loop controller

[0103] exist Figure 2 In this design, the positive-sequence current component closed-loop controller adopts a proportional resonant controller. The transfer function of the corresponding controller is shown in equation (18):

[0104] ;

[0105] In the formula, K p_(xy_p) K is the proportionality coefficient. r_(xy_p) ω is the resonance coefficient. c_(xy_p) ω is the resonant bandwidth. e The fundamental frequency electrical angular velocity.

[0106] (4) Reference voltage setting method

[0107] Will Figure 2 The output value of the positive-sequence current component closed-loop controller shown is used as the positive-sequence reference voltage value u in the xy subspace. x_p ref u y_p ref Meanwhile, since the negative sequence current component of the xy subspace is not subject to closed-loop control, the negative sequence reference voltage value u of the xy subspace can be directly set. x_n ref =0、u y_n ref =0. Then, by adding the positive-sequence reference voltage value and the negative-sequence reference voltage value of the xy subspace, the overall reference voltage value u of the xy subspace can be obtained. x ref uy ref ,Right now:

[0108] ;

[0109] On the other hand, regarding the dq subspace current (i d i q Control, based on equation (4), setting i d The reference value is 0A, and i is set. q The reference value is the outer loop control output value I of the speed. When there is no phase loss fault in the motor, i can be controlled by the proportional-integral controller. d i q The control is in the ideal form shown in equation (4). However, when a phase loss fault occurs, the dq subspace will be introduced with a second-harmonic AC voltage disturbance. Therefore, in order to make i d i q Even in the case of a phase loss, the current is still controlled as shown in equation (4). A second-order resonant term can be introduced into the current controller to form a proportional-integral resonant controller. Furthermore, to achieve diagnostic-free self-fault-tolerant control, the current control method of the dq subspace should remain consistent before and after the phase loss. Therefore, regardless of whether a phase loss fault occurs, this invention uses a proportional-integral resonant controller for closed-loop control of the dq subspace current. The transfer function of the corresponding controller is shown in equation (20):

[0110] ;

[0111] In the formula, K p_(dq) K is the proportionality coefficient. i_(dq) K is the integral coefficient. r_(dq) ω is the resonance coefficient. c_(dq) This is the resonant bandwidth.

[0112] Furthermore, the output value of the dq subspace current closed-loop controller is the dq subspace reference voltage value u. d ref u q ref By analyzing u d ref u q ref By performing the inverse Park transformation shown in equation (21), the reference voltage value u in the αβ subspace can be obtained. α ref u β ref :

[0113] ;

[0114] Finally, based on the classical vector space decoupling model, a reference voltage value u that can be synthesized in the αβ subspace is selected. αref u β ref and xy subspace reference voltage value u x ref u y ref The basic voltage vector is obtained, and the driving signal S of each phase of the motor is derived by calculating the duration of action of each vector. A1 S B1 S C1 S A2 S B2 S C2 This enables control of the motor.

[0115] Based on the above analysis, Figure 3 An overall control block diagram of the control method proposed in this invention is provided.

[0116] The following uses a phase C2 open circuit fault as an example to illustrate... Figure 3 The principle of self-fault tolerance without diagnosis under the control method shown is explained.

[0117] (1) Before the phase loss fault occurs, the positive sequence current component (i) in the xy subspace x_p i y_p The positive-sequence current component will converge to 0A under the closed-loop control. Meanwhile, the negative-sequence current component is not affected by the closed-loop control. There is no external negative-sequence voltage excitation in the xy subspace (i.e., Figure 2 As shown u x_n ref =0、u y_n ref In the case of (=0), the negative sequence current component of the xy subspace (i) can be considered as... x_n i y_n The value is equal to 0. Therefore, before a phase loss fault occurs, Figure 3 The control method shown can make the xy subspace current (i x i y The current converges to the ideal form shown in equation (8), thereby causing the current in each phase of the motor to converge to the ideal form shown in equation (5).

[0118] (2) After the C2 phase open circuit fault occurs, due to i C2 Since they are forced to zero, after the vector space decoupling transformation shown in equation (1), the currents in each phase have the forced relationship shown in equation (22) between the αβ subspace current and the xy subspace current.

[0119] ;

[0120] When a phase loss fault occurs, the dq subspace current controller can enable i d i qWhen maintained in the form shown in equation (4), it can be seen from the inverse transformation of the Park transformation shown in equation (2) that the y-axis current i in the xy subspace after the phase loss fault is... y It has the following characteristics:

[0121] ;

[0122] In the case of a phase loss, since neither the control structure nor the reference current has changed since the fault, the positive sequence current component (i) in the xy subspace... x_p i y_p The positive-sequence current component will still converge to 0A under the positive-sequence current closed-loop control. On the other hand, even the negative-sequence current component (i) in the xy subspace... x_n i y_n It is not subject to closed-loop control, but because i y =i y_p +i y_n And i y Satisfying equation (23), therefore when the positive sequence current i along the y-axis... y_p When the phase loss gradually converges to 0A after the phase loss, the negative sequence current i on the y-axis is... y_n It will be adjusted synchronously to:

[0123] ;

[0124] Furthermore, due to the negative sequence component i in the xy subspace current x_n i y_n To determine the real-time i in each control cycle x i y The result obtained through positive and negative sequence decomposition means that regardless of the negative sequence current i along the y-axis... y_n Why is the negative sequence current i on the x-axis such that... x_n All will be with i y_n Maintain the same amplitude, and the phase is different from i. y_n Leading by 90°. Therefore, when the negative sequence current i along the y-axis... y_n When it takes the form shown in equation (24), the negative sequence current i on the x-axis x_n It must possess the characteristics shown in equation (25):

[0125] ;

[0126] As can be seen from equations (24) and (25), even if the negative sequence component of the xy subspace current is not subject to closed-loop control, both the positive and negative sequence current components can converge to the ideal fault-tolerant values ​​shown in equations (13) and (14) under the condition of phase C2 open circuit. Therefore, after the phase C2 open circuit fault occurs, Figure 3 The control method shown can make the xy subspace current (i x i yThe current converges to the ideal form shown in equation (10), thereby causing the current in each phase of the motor to converge to the ideal fault-tolerant form shown in equation (7).

[0127] When the faulty phase is another phase, a similar analysis method can be used to determine the cause. Figure 3 The control method shown can also cause the current in each phase of the motor to converge to the corresponding ideal fault-tolerant form. The specific analysis process will not be elaborated further. Therefore, relying on... Figure 3 The uniformity of the control model shown (i.e., regardless of whether there is a phase loss fault or which phase the phase loss fault occurs in, the control structure and reference current are not adjusted in any way) can achieve a self-fault-tolerant control effect without fault diagnosis after a single-phase open circuit fault occurs.

[0128] To verify the effectiveness of the proposed diagnostic-free self-fault-tolerant control method for single-phase open-circuit faults in dual-redundant permanent magnet synchronous motors, simulation software was used for analysis and verification. The simulation parameter settings are shown in Table 1. Based on the parameters in Table 1, i can be calculated. q The ideal value is I = 8.4A. Figures 4 to 8 The control effect of the proposed control method is demonstrated when the motor switches from a normal state to a B1 phase open circuit state. Throughout the entire process, the control system does not perform any fault diagnosis operations.

[0129] Table 1 Simulation parameter settings for the dual-redundant permanent magnet synchronous motor drive system: ;

[0130] On the one hand, before a phase loss fault occurs, by Figure 4 It can be known that the actual current (i) in the dq subspace d i q All are controlled to the ideal value shown in equation (4), thereby making Figure 5 The motor speed and electromagnetic torque shown remain stable before the phase loss. Furthermore, by Figure 6 and Figure 7 It can be seen that the actual positive sequence current component (i) in the xy subspace x_p i y_p ) and negative sequence current component (i x_n i y_n Before the phase loss, all values ​​were 0A, which in turn caused i x i y All are ideal values ​​of 0A as shown in equation (8). Since the currents in the dq and xy subspaces have converged to their ideal values, the currents in each phase are balanced (satisfying equation (5)). This verifies that the control method proposed in this invention can make the motor operate in a balanced power state in each phase before phase loss.

[0131] On the other hand, after a phase loss fault occurs, by Figure 4 It can be known that i d i qBoth can be kept constant, thus ensuring Figure 5 The motor speed and electromagnetic torque shown were not affected by the phase loss fault. Meanwhile, i x_p i y_p Even after phase loss, all phases converge to 0A, verifying that... Figure 3 The effectiveness of closed-loop control of the positive-sequence current component in the xy subspace. Furthermore, in i q With a steady-state amplitude of I = 8.4A, it can be seen from equation (12) that the negative sequence component (i) of the ideal fault-tolerant current in the xy subspace under phase B1 disconnection is... x_n i y_n The amplitude is 8.4A. Figure 7 In the simulation verification results shown, under the B1 phase disconnection, i x_n i y_n The actual amplitude is approximately 8.4A. Therefore, even though the negative sequence current component of the xy subspace is not under closed-loop control, it still ensures that the corresponding current component tends to the ideal fault-tolerant value. The corresponding characteristics of the positive and negative sequence current components of the xy subspace ensure that after a phase loss, the power of the three-phase winding (A1B1C1) where the faulty phase is located is adjusted to zero, while another healthy three-phase winding (A2B2C2) bears all the power. The corresponding characteristics can be derived from... Figure 8 The current waveforms of each phase after the phase loss are shown, confirming this. Therefore, after a phase loss fault occurs, the control method proposed in this invention can accurately disconnect the three-phase winding containing the faulty phase without locating the specific faulty phase, achieving self-fault-tolerant operation.

Claims

1. A self-fault-tolerant, diagnostic-free control method for single-phase circuit interruption of a dual-redundant permanent magnet synchronous motor, characterized in that, The control process is applicable to both situations where a phase loss fault has not occurred and situations where a phase loss fault has occurred, and is not limited by which phase the phase loss fault occurs. The control process is executed consistently in all cases, thereby eliminating the reliance on fault diagnosis. The control process includes the following steps: Step 1: In each control cycle, the current of each phase of the motor is collected in real time, and the αβ subspace current i is obtained through vector space decoupling transformation. α i β and the xy subspace current i x i y ; Step 2: Perform a Park transformation on the αβ subspace current to obtain the dq subspace current i d i q ; Step 3: Perform closed-loop control on the dq subspace current to obtain the dq subspace reference voltage value u. d ref u q ref ; Step 4: Decompose the xy subspace current into positive and negative sequence components to obtain the positive sequence current component i in the xy subspace. x_p i y_p and the negative sequence current component i in the xy subspace x_n i y_n ; Step 5: For the xy subspace current, perform closed-loop control on the positive sequence current component to obtain the xy subspace positive sequence reference voltage value u. x_p ref u y_p ref Directly set the negative sequence reference voltage value u corresponding to the negative sequence current component. x_n ref =0、u y_n ref =0; Based on this, the overall reference voltage value u of the xy subspace is obtained. x ref u y ref ; Step 6: Based on the dq subspace reference voltage values ​​obtained in Step 3 and the xy subspace reference voltage values ​​obtained in Step 5, perform space vector pulse width modulation to obtain the motor's phase drive signals S. A1 S B1 S C1 S A2 S B2 S C2 This completes the entire control process.

2. The method for single-phase circuit breaking diagnosis-free self-fault-tolerant control of a dual-redundant permanent magnet synchronous motor according to claim 1, characterized in that, Step 1 includes: For each phase current i in each control cycle A1 ~i C2 After data acquisition, the αβ subspace current i is obtained through the vector space decoupling transformation process shown in the following equation. α i β and the xy subspace current i x i y : 。 3. The method for single-phase circuit breaking diagnosis-free self-fault-tolerant control of a dual-redundant permanent magnet synchronous motor according to claim 1, characterized in that, Step 2 includes: The αβ subspace current i obtained by the vector space decoupling transformation α i β The dq subspace current i is obtained from the Park transformation process shown in the following equation. d i q : ， In the formula, θ e The electric angle of the motor rotor.

4. The method for single-phase circuit breaking diagnosis-free self-fault-tolerant control of a dual-redundant permanent magnet synchronous motor according to claim 1, characterized in that, Step 3 includes: Step 301: Set the dq subspace current i d The reference value is 0A, and the current i in the dq subspace is set. q The reference value is the outer loop control output value I of the rotational speed; Step 302: Perform closed-loop control on the dq subspace current. The closed-loop controller adopts a proportional-integral resonant structure with a resonant frequency of twice the fundamental frequency. The transfer function of the closed-loop controller is G. PIR_(dq) (s) can be specifically expressed as: ， In the formula, K p_(dq) K is the proportionality coefficient. i_(dq) K is the integral coefficient. r_(dq) ω is the resonance coefficient. c_(dq) ω is the resonant bandwidth. e The fundamental frequency electrical angular velocity; Step 303: Use the output value of the dq subspace current closed-loop controller as the dq subspace reference voltage value u. d ref u q ref .

5. The method for single-phase circuit breaking diagnosis-free self-fault-tolerant control of a dual-redundant permanent magnet synchronous motor according to claim 1, characterized in that, Step 4 includes: Step 401: Convert the x-axis component i of the xy subspace current x Shifting 90° to the right yields the x-axis phase-shifted current i. x_shift_-90° Simultaneously, the y-axis component i of the current in the xy subspace is... y Shifting 90° to the left yields the y-axis phase-shifted current i. y_shift_+90° ; Step 402: Obtain the positive-sequence current component i in the decomposed xy subspace using the following two equations. x_p i y_p and the negative sequence current component i in the xy subspace x_n i y_n : ， 。 6. The method for single-phase circuit breaking diagnosis-free self-fault-tolerant control of a dual-redundant permanent magnet synchronous motor according to claim 1, characterized in that, Step 5 includes: Step 501: For the positive sequence current component i in the xy subspace x_p i y_p This is incorporated into closed-loop control, and a corresponding current reference value i is set. x_p ref i y_p ref for: ； Step 502: When performing closed-loop control on the positive sequence current component of the xy subspace, the closed-loop controller adopts a proportional resonant structure, and the closed-loop controller transfer function G... PR_(xy_p) (s) can be specifically expressed as: ， In the formula, K p_(xy_p) K is the proportionality coefficient. r_(xy_p) ω is the resonance coefficient. c_(xy_p) The resonant bandwidth; Step 503: When performing closed-loop control on the positive sequence current component of the xy subspace, the output value of the closed-loop controller for the positive sequence current component of the xy subspace is used as the positive sequence reference voltage value u of the xy subspace. x_p ref u y_p ref ; Step 504: For the negative sequence current component i in the xy subspace x_n i y_n This excludes it from closed-loop control, and directly sets the negative sequence reference voltage value u in the xy subspace. x_n ref =0、u y_n ref =0; Step 505: By adding the positive-sequence reference voltage value of the xy subspace obtained in step 503 to the negative-sequence reference voltage value of the xy subspace set in step 504, the overall reference voltage value u of the xy subspace is obtained. x ref u y ref ,Right now: 。 7. The method for single-phase circuit interruption-free self-fault-tolerant control of a dual-redundant permanent magnet synchronous motor according to claim 1, characterized in that, Step 6 includes: Step 601: Apply the dq subspace reference voltage value u obtained in step 3. d ref u q ref Performing the inverse Park transform shown in the following equation yields the reference voltage value u in the αβ subspace. α ref u β ref : ； Step 602: Based on the classical vector space decoupling model, select a synthesizable αβ subspace reference voltage value u. α ref u β ref and xy subspace reference voltage value u x ref u y ref The basic voltage vector is obtained, and the driving signal S of each phase of the motor is derived by calculating the duration of action of each vector. A1 S B1 S C1 S A2 S B2 S C2 .

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