Fault-tolerant control system and method for high-resistance connection fault of three-phase permanent magnet synchronous motor

Abstract

The invention discloses a fault-tolerant control system and method for a high-resistance connection fault of a three-phase permanent magnet synchronous motor, and belongs to the field of synchronous motor control, the fault-tolerant control system comprises a rotating speed loop control module, a current loop control module and an SVPWM modulation module, the rotating speed loop control module comprises an encoder and a resonant sliding mode controller, and the rotating speed loop control module is used for obtaining a target current component; the current loop control module is used for generating a voltage control signal based on a current difference value between the target current component and the corresponding real-time current component; the SVPWM modulation module is used for driving the to-be-monitored three-phase permanent magnet synchronous motor to operate based on the generated voltage control signal. According to the fault-tolerant control system and method for the high-resistance connection fault of the three-phase permanent magnet synchronous motor, the resonant sliding mode controller is adopted in the rotating speed loop, the self-adaptive notch filter is introduced into the current loop, and the torque ripple and the rotating speed fluctuation of the three-phase permanent magnet synchronous motor under the high-resistance connection fault can be effectively inhibited without additional hardware, so that the fault tolerance of the high-resistance connection fault of the three-phase permanent magnet synchronous motor is improved. And the fault-tolerant performance and the operation stability of the motor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of synchronous motor control, and in particular to a fault-tolerant control system and method for a three-phase permanent magnet synchronous motor with a high-resistance connection fault. Background Art

[0002] With the rapid development of modern industry and technology, electric motors, as a key power source, have a significant impact on the operational efficiency and stability of numerous applications. Permanent magnet synchronous motors, with their significant advantages of high reliability, high power density, and excellent controllability, have found widespread and in-depth application in cutting-edge fields such as flywheel energy storage systems, electric vehicles, industrial automation, and marine electric propulsion.

[0003] However, in the above-mentioned application scenarios, the working environment is often extremely harsh, with adverse factors such as high temperature, high humidity, strong electromagnetic interference, and mechanical vibration coexisting. At the same time, long-term high-load operation also makes the motor under tremendous pressure at all times, which greatly increases the risk of failure. Among them, high-resistance connection failure, as a typical representative of permanent magnet synchronous motor failure types, refers to the resistance between the output terminal of a certain phase inverter and the terminal of the motor is greater than the resistance of other phases, causing the three-phase current of the three-phase permanent magnet synchronous motor in the stationary coordinate system to be unbalanced. Among them, the current mapped to the dq axis (synchronous rotating coordinate system) of the permanent magnet synchronous motor is the second harmonic. This fault is usually caused by the terminal or connection part being subjected to long-term vibration, corrosion or pollution, resulting in damage to the contact surface, which in turn causes an abnormal increase in connection resistance.

[0004] Once a high-resistance connection fault occurs, it disrupts the original impedance balance of the stator's three-phase circuit, causing impedance inconsistency in the three-phase circuit and generating unbalanced current in the motor. However, traditional field-oriented control (FOC) methods are unable to effectively suppress this unbalanced current, resulting in significant fluctuations in the motor's electromagnetic torque. If this torque fluctuation is not effectively controlled in a timely manner, it will pose a serious threat to the stable operation of the motor. In extreme cases, it may even cause catastrophic damage to the entire drive system, leading to a series of serious consequences such as production interruptions, equipment failure, and safety accidents, resulting in huge economic losses to related industries. Summary of the Invention

[0005] The purpose of the present invention is to provide a fault-tolerant control system and method for a three-phase permanent magnet synchronous motor with a high-resistance connection fault, so as to solve the above-mentioned technical problems.

[0006] To achieve the above-mentioned objectives, the present invention provides a fault-tolerant control system for a three-phase permanent magnet synchronous motor with a high-resistance connection fault, comprising a speed loop control module, a current loop control module and an SVPWM modulation module, wherein the speed loop control module comprises an encoder and a resonant sliding mode controller, which is used to obtain the rotation angle of the three-phase permanent magnet synchronous motor to be monitored using the encoder, and then obtain the target current component in combination with the resonant sliding mode controller; the current loop control module is used to generate a voltage control signal based on the current difference between the target current component and the corresponding real-time current component; the SVPWM modulation module is used to drive the three-phase permanent magnet synchronous motor to be monitored to operate based on the generated voltage control signal.

[0007] Preferably, the current loop control module includes a current sensor, an adaptive notch filter and a PI controller, wherein the current sensor is used to collect the real-time three-phase current of the three-phase permanent magnet synchronous motor to be monitored, the PI controller is used to convert the real-time three-phase current into a real-time current component, and generate a voltage control signal based on the current difference between the target current component and the corresponding real-time current component, and the adaptive notch filter is used to extract the double frequency component existing in the target current component, and suppress the double frequency component appearing in the current loop based on the extracted double frequency component.

[0008] A method for a fault-tolerant control system for a three-phase permanent magnet synchronous motor with a high-resistance connection fault comprises the following steps:

[0009] S1. Generate q-axis target current component: Use an encoder to obtain the rotation angle of the three-phase permanent magnet synchronous motor to be monitored, and then obtain the actual speed of the three-phase permanent magnet synchronous motor to be monitored. Then, calculate the speed difference between the target speed and the actual speed to obtain the q-axis target current component;

[0010] S2. Generate voltage control signal: Convert the real-time three-phase current into real-time current components in a synchronously rotating coordinate system, calculate the current difference between the q-axis target current component and the d-axis target current and the real-time current components in the synchronously rotating coordinate system, and then input the current difference into the PI controller to generate a voltage control signal;

[0011] S3. Drive the monitored three-phase permanent magnet synchronous motor to operate based on the generated voltage control signal.

[0012] Preferably, step S1 specifically includes the following steps:

[0013] S11, set the acquisition time interval to Δt, the rotation angle under the time interval Δt to Δθ, and the actual speed of the three-phase permanent magnet synchronous motor to be monitored

[0014] S12, set the target speed to ω ref , calculate the speed difference between the target speed and the actual speed x = ω ref -ωm ;

[0015] S13. Input the rotational speed difference x into the resonant sliding mode controller to calculate the q-axis target current component i q ;

[0016] S131. Considering the double-frequency torque disturbance caused by the high-resistance fault, construct the mechanical equation of the three-phase permanent magnet synchronous motor to be monitored:

[0017]

[0018] where, K t represents the torque constant; T L represents the load torque; B represents the friction coefficient; ω m represents the mechanical angular velocity of the three-phase permanent magnet synchronous motor to be monitored; ΔTsin(2ω e t) represents the double-frequency torque disturbance caused by the high-resistance connection fault; ω e represents the electrical angular velocity of the three-phase permanent magnet synchronous motor to be monitored; J represents the moment of inertia;

[0019] S132. Input the rotational speed difference x into the resonant sliding mode controller. Considering the double-frequency disturbance component caused by the high-resistance fault, introduce a resonant term into the sliding surface and design the sliding surface function:

[0020] S = x + c∫x + K r G R x(2);

[0021] where, S represents the sliding surface function; c represents the integral coefficient; K r represents the resonant coefficient; G R represents the resonant function;

[0022] where,

[0023]

[0024] where, ω r represents the double fundamental frequency, and ω r = 2ω e , ω c represents the effective bandwidth of the resonant function;

[0025] S133. Sliding mode control based on the exponential reaching law:

[0026]

[0027] where, represents the derivative of the sliding surface function S with respect to time; ∈ and k both represent the reaching law parameters; sign(·) represents the switching function;

[0028] where,

[0029]

[0030] S134. Derivative the sliding surface function to obtain:

[0031]

[0032] Where, Indicates the derivative of actual speed with respect to time; G RD Represents the resonance function G R The differential of

[0033] in,

[0034]

[0035] Combining equations (6), (7), and (8), we can obtain the q-axis target current component i q :

[0036]

[0037] Preferably, step S2 specifically includes the following steps:

[0038] S21. Use a current sensor to collect the real-time three-phase current of the three-phase permanent magnet synchronous motor to be monitored, and set the three-phase current expression of the three-phase permanent magnet synchronous motor to be monitored in the stationary coordinate system after a high-resistance connection fault occurs as follows:

[0039]

[0040] In the formula, i a 、i b 、i c Respectively represent the A-phase, B-phase, and C-phase currents of the three-phase permanent magnet synchronous motor to be monitored; I + and I - Represent the amplitudes of positive sequence current and negative sequence current respectively; and They represent the initial phases of the positive sequence current and the negative sequence current respectively; ω represents the angular frequency of the three-phase permanent magnet synchronous motor to be monitored; t represents time;

[0041] S22. Convert the three-phase current in the stationary coordinate system into the real-time current components in the synchronous rotating coordinate system through the Clark transformation matrix and the Park transformation matrix:

[0042]

[0043] Where θ represents the rotation angle;

[0044] From θ=ωt, we can simplify formula (11) to obtain:

[0045]

[0046] Wherein, i sr represents the real-time current component in the synchronous rotating coordinate system; and respectively represent the positive-sequence current amplitude and the negative-sequence current amplitude on the d-axis; and respectively represent the positive-sequence current amplitude and the negative-sequence current amplitude on the q-axis; and and respectively represent the second-harmonic current components on the d-axis and the q-axis;

[0047] S23. Calculate the target current i q on the q-axis and the target current i d on the d-axis, and the current difference between them and the real-time current component in the synchronous rotating coordinate system, and input the current difference into a PI controller to generate a voltage control signal.

[0048] Preferably, in step S23, an adaptive notch filter is used to suppress the second harmonic. During this process, the parameters of the adaptive notch filter are dynamically adjusted through the LMS algorithm to track and cancel the second-harmonic component in the current loop in real time;

[0049] It specifically includes the following steps:

[0050] Set the difference between the real-time current component i sr (n) in the synchronous rotating coordinate system after the nth iteration and the second harmonic y(n) of the real-time current component extracted by the adaptive notch filter as e(n), then there is:

[0051] y(n) = w1(n)sin(ω nf t) + w2(n)cos(ω nf t) (13);

[0052] e(n) = i sr (n) - y(n) (14);

[0053] Wherein, ω nf represents the required notch frequency, and ω nf = 2ω; w1(n) and w2(n) both represent weight coefficients;

[0054] Update w1(n) and w2(n) using the LMS algorithm:

[0055]

[0056] Wherein, μ represents the step size factor; w1(n + 1) and w2(n + 1) represent the updated weight coefficients.

[0057] Therefore, the present invention adopts the above-mentioned fault-tolerant control system and method for high-resistance connection failure of the three-phase permanent magnet synchronous motor, which has the following beneficial effects:

[0058] 1. Effectively suppress torque ripple: An adaptive notch filter (ANF) is used in the current loop, and parameters are dynamically adjusted based on the LMS algorithm (least mean square algorithm). This can effectively and in real time offset the second harmonic current of the dq axes, reduce torque ripple, and improve motor operation smoothness. By introducing a resonant sliding mode controller (RSMC) in the speed loop and utilizing a sliding mode surface function containing a resonant term, the residual component can be accurately compensated and suppressed, ensuring stable motor operation under complex operating conditions.

[0059] 2. Improve speed control accuracy: The control strategy based on the speed difference can quickly and accurately track the target speed, effectively deal with the speed fluctuation problem caused by high resistance faults, and ensure that the actual motor speed closely follows the set value, meeting the speed accuracy requirements of various working conditions;

[0060] 3. Enhanced system fault tolerance: Without adding additional hardware, relying solely on algorithm optimization, the system can maintain stable operation when a high-resistance connection fault occurs in a three-phase permanent magnet synchronous motor, reducing the impact of the fault on motor performance and improving the motor's reliability and continued operation capability in the event of a fault.

[0061] 4. Optimize current control performance: Coordinate transformation combined with an adaptive notch filter can effectively separate and suppress the harmonic components in the current, allowing the current loop PI controller to focus on regulating the fundamental component, thereby making the motor current closer to the ideal state, improving the accuracy and speed of current control, and thus improving the overall efficiency and performance of the motor;

[0062] 5. Good versatility and scalability: Based on the improvement of the field-oriented control (FOC) strategy, it is easy to integrate with the existing motor control system, and the algorithm parameters can be flexibly adjusted and optimized according to different motor models and working conditions. It has wide applicability and potential for further expansion and upgrading in permanent magnet synchronous motor applications in various fields such as industry and home appliances.

[0063] In summary, the present invention can improve the output performance of a permanent magnet synchronous motor when a high-resistance connection fault occurs under traditional vector control, effectively improving equipment safety, and does not require additional hardware, is low-cost, and is simple to implement.

[0064] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a structural block diagram of the fault-tolerant control system for a three-phase permanent magnet synchronous motor with high-resistance connection failure according to the present invention;

[0066] Figure 2 Topological circuit diagram of the three - phase permanent - magnet synchronous motor of the present invention during high - resistance fault;

[0067] Figure 3 Principle block diagram of the adaptive notch filter of the fault - tolerant control system for high - resistance connection fault of the three - phase permanent - magnet synchronous motor of the present invention;

[0068] Figure 4 Schematic diagram for extracting harmonic components in the q - axis current using the adaptive notch filter of the present invention;

[0069] Figure 5 Torque comparison simulation result diagram of the fault - tolerant control method proposed by the present invention and the traditional method under high - resistance connection fault;

[0070] Figure 6 Speed comparison simulation result diagram of the fault - tolerant control method proposed by the present invention and the traditional method under high - resistance connection fault. Detailed implementation manners

[0071] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following further details the embodiments of the present invention with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout.

[0072] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non - exclusive inclusion. For example, a process, method, system, product or server that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0073] The following details the embodiments of the present invention with reference to the drawings.

[0074] As Figure 1-Figure 5As shown, a fault-tolerant control system for a three-phase permanent magnet synchronous motor with a high-resistance connection fault includes a speed loop control module, a current loop control module and an SVPWM modulation module, wherein the speed loop control module includes an encoder and a resonant sliding mode controller, which is used to use the encoder to obtain the rotation angle of the three-phase permanent magnet synchronous motor to be monitored, and then combine with the resonant sliding mode controller to obtain the target current component; the current loop control module is used to generate a voltage control signal based on the current difference between the target current component and the corresponding real-time current component; the SVPWM modulation module is used to drive the three-phase permanent magnet synchronous motor to be monitored to operate based on the generated voltage control signal.

[0075] The current loop control module includes a current sensor, an adaptive notch filter and a PI controller, wherein the current sensor is used to collect the real-time three-phase current of the three-phase permanent magnet synchronous motor to be monitored, the PI controller is used to convert the real-time three-phase current into real-time current components, and generate a voltage control signal based on the current difference between the target current component and the corresponding real-time current component, and the adaptive notch filter is used to extract the double frequency component existing in the target current component, and suppress the double frequency component appearing in the current loop based on the extracted double frequency component.

[0076] A method for a fault-tolerant control system for a three-phase permanent magnet synchronous motor with a high-resistance connection fault comprises the following steps:

[0077] S1. Generate q-axis target current component: Use an encoder to obtain the rotation angle of the three-phase permanent magnet synchronous motor to be monitored, and then obtain the actual speed of the three-phase permanent magnet synchronous motor to be monitored. Then, calculate the speed difference between the target speed and the actual speed to obtain the q-axis target current component, and regard the q-axis target current component as the input reference signal of the q-axis component in the current loop;

[0078] Step S1 specifically includes the following steps:

[0079] S11, set the acquisition time interval to Δt, the rotation angle under the time interval Δt to Δθ, and the actual speed of the three-phase permanent magnet synchronous motor to be monitored

[0080] S12, set the target speed to ω ref , calculate the speed difference between the target speed and the actual speed x = ω ref -ω m ;

[0081] S13, input the speed difference x into the resonant sliding mode controller, calculate the q-axis target current component i q ;

[0082] S131. Considering the double frequency torque disturbance caused by high resistance fault, the mechanical equation of the three-phase permanent magnet synchronous motor to be monitored is constructed:

[0083]

[0084] In the formula, K t represents the torque constant; T L represents the load torque; B represents the friction coefficient; ω m represents the mechanical angular velocity of the three-phase permanent magnet synchronous motor to be monitored; ΔTsin(2ω e t) represents the double-frequency torque disturbance caused by the high-resistance connection fault; ω e represents the electrical angular velocity of the three-phase permanent magnet synchronous motor to be monitored; J represents the moment of inertia;

[0085] S132. Input the speed difference x into the resonant sliding mode controller. Considering the double-frequency disturbance component caused by the high-resistance fault, introduce a resonant term into the sliding mode surface and design the sliding mode surface function:

[0086] S = x + c∫x + K r G R x(2);

[0087] In the formula, S represents the sliding mode surface function; c represents the integral coefficient; K r represents the resonant coefficient; G R represents the resonant function;

[0088] Among them,

[0089]

[0090] In the formula, ω r represents the double fundamental frequency, and ω r = 2ω e , ω c represents the effective bandwidth of the resonant function controller;

[0091] S133. Sliding mode control based on the exponential reaching law:

[0092]

[0093] In the formula, represents the derivative of the sliding mode surface function S with respect to time; ∈ and k both represent the reaching law parameters; sign(·) represents the switching function;

[0094] Among them,

[0095]

[0096] S134. Take the derivative of the sliding mode surface function to obtain:

[0097]

[0098] In the formula, represents the derivative of the actual speed with respect to time; GRD Represents the resonance function G R The differential of

[0099] in,

[0100]

[0101] Combining equations (6), (7), and (8), we can obtain the q-axis target current component i q :

[0102]

[0103] The following stability analysis is performed on the resonant sliding mode control method of the present invention using the Lyapunov stability criterion:

[0104] Let Lyapunov function be V, and V is always greater than 0, and we have:

[0105]

[0106]

[0107] In the formula, Denotes the derivative of V, we know Therefore, the constructed sliding surface function can ensure the stability of the system and the speed difference is 0, which proves the effectiveness of the present invention.

[0108] S2. Generate voltage control signal: Convert the real-time three-phase current into real-time current components in a synchronously rotating coordinate system, calculate the current difference between the q-axis target current component and the d-axis target current and the real-time current components in the synchronously rotating coordinate system, and then input the current difference into the PI controller to generate a voltage control signal;

[0109] Step S2 specifically includes the following steps:

[0110] S21. Use a current sensor to collect the real-time three-phase current of the three-phase permanent magnet synchronous motor to be monitored, and set the three-phase current expression of the three-phase permanent magnet synchronous motor to be monitored in the stationary coordinate system after a high-resistance connection fault occurs as follows:

[0111]

[0112] In the formula, i a 、i b 、i c Respectively represent the A-phase, B-phase, and C-phase currents of the three-phase permanent magnet synchronous motor to be monitored; I + and I - Represent the amplitudes of positive sequence current and negative sequence current respectively; and respectively represent the initial phases of the positive-sequence current and the negative-sequence current; ω represents the angular frequency of the three-phase permanent magnet synchronous motor to be monitored; t represents time;

[0113] S22. Convert the three-phase current in the stationary coordinate system into the real-time current components in the synchronous rotating coordinate system through the Clark transformation matrix and the Park transformation matrix:

[0114]

[0115] In the formula, θ represents the rotation angle;

[0116] From θ = ωt, by simplifying formula (11), we get:

[0117]

[0118] In the formula, i sr represents the real-time current components in the synchronous rotating coordinate system; and respectively represent the amplitudes of the positive-sequence current and the negative-sequence current on the d-axis; and respectively represent the amplitudes of the positive-sequence current and the negative-sequence current on the q-axis; and and respectively represent the second harmonic current components on the d-axis and the q-axis;

[0119] S23. Calculate the current differences between the q-axis target current i q and the d-axis target current i d and the real-time current components in the synchronous rotating coordinate system, and input the current differences into the PI controller to generate a voltage control signal.

[0120] From the electromagnetic torque expression of the three-phase permanent magnet synchronous motor to be monitored:

[0121]

[0122] In the formula, T e represents the electromagnetic torque; p represents the number of pole pairs; ψ f represents the permanent magnet flux linkage of the three-phase permanent magnet synchronous motor to be monitored; L q and L d respectively represent the d-axis and q-axis inductances;

[0123] Substitute formulas (10), (11), and (12) into formula (16) to get:

[0124]

[0125] In the formula, T e0 、T e2 and T e4They represent the fundamental component, double frequency component and quadruple frequency component of the electromagnetic torque respectively; represents the phase of the double frequency component; A represents the amplitude of the double frequency component.

[0126] It can be seen that after a high-resistance connection fault occurs in the permanent magnet synchronous motor, a second harmonic current will be generated in the synchronous rotating coordinate system, causing the electromagnetic torque to pulsate at double and quadruple frequencies. Therefore, in step S23, an adaptive notch filter is used to suppress the second harmonic. In this process, the parameters of the adaptive notch filter are dynamically adjusted through the LMS algorithm to track and offset the second harmonic component in the current loop in real time. The LMS (Least Mean Squares) algorithm, as a method based on Wiener filtering theory, uses instantaneous values to estimate the gradient vector and continuously updates the weight coefficient of the adaptive filter by minimizing the energy of the error signal. It has significant advantages such as simple design and strong robustness.

[0127] It specifically includes the following steps:

[0128] Set the real-time current component i in the synchronous rotating coordinate system after the nth iteration sr The difference between (n) and the second harmonic y(n) of the real-time current component extracted by the adaptive notch filter in the synchronous rotating coordinate system is e(n), then:

[0129] y(n)=w1(n)sin(ω nf t)+w2(n)cos(ω nf t) (13);

[0130] e(n)=i sr (n)-y(n) (14);

[0131] In the formula, ω nf represents the desired notch frequency, and ω nf =2ω; w1(n) and w2(n) both represent weight coefficients;

[0132] Use the LMS algorithm to update w1(n) and w2(n):

[0133]

[0134] Where μ represents the step size factor; w1(n+1) and w2(n+1) represent the updated weight coefficients.

[0135] S3. Drive the monitored three-phase permanent magnet synchronous motor to operate based on the generated voltage control signal.

[0136] like Figure 5 and Figure 6As shown, after a high-resistance connection fault occurs in the permanent magnet synchronous motor, the present invention can suppress torque fluctuations, smooth the motor speed, and improve the motor performance, thus proving the effectiveness of the present invention.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A fault-tolerant control system for high-resistance connection faults of a three-phase permanent magnet synchronous motor, characterized in that: It includes a speed loop control module, a current loop control module, and an SVPWM modulation module. The speed loop control module includes an encoder and a resonant sliding mode controller, which are used to obtain the rotation angle of the three-phase permanent magnet synchronous motor to be monitored by using the encoder, and then obtain the target current component in combination with the resonant sliding mode controller; The current loop control module is used to generate a voltage control signal based on the current difference between the target current component and the corresponding real-time current component; The SVPWM modulation module is used to drive the operation of the three-phase permanent magnet synchronous motor to be monitored based on the generated voltage control signal.

2. The fault-tolerant control system for high-resistance connection faults of a three-phase permanent magnet synchronous motor according to claim 1, characterized in that: The current loop control module includes a current sensor, an adaptive notch filter, and a PI controller. Among them, the current sensor is used to collect the real-time three-phase current of the three-phase permanent magnet synchronous motor to be monitored. The PI controller is used to convert the real-time three-phase current into a real-time current component, and generate a voltage control signal based on the current difference between the target current component and the corresponding real-time current component. The adaptive notch filter is used to extract the second harmonic component existing in the target current component, and suppress the second harmonic component appearing in the current loop based on the extracted second harmonic component.

3. The method of the fault-tolerant control system for high-resistance connection faults of a three-phase permanent magnet synchronous motor according to claim 2 above, characterized in that: It includes the following steps: S1. Generate the q-axis target current component: Use the encoder to obtain the rotation angle of the three-phase permanent magnet synchronous motor to be monitored, and then obtain the actual speed of the three-phase permanent magnet synchronous motor to be monitored. Then, calculate the speed difference between the target speed and the actual speed to obtain the q-axis target current component; S2. Generate a voltage control signal: Convert the real-time three-phase current into a real-time current component in the synchronous rotating coordinate system, calculate the current difference between the q-axis target current component and the d-axis target current and the real-time current component in the synchronous rotating coordinate system, and then input the current difference into the PI controller to generate a voltage control signal; S3. Drive the operation of the three-phase permanent magnet synchronous motor to be monitored based on the generated voltage control signal.

4. The method of the fault-tolerant control system for high-resistance connection faults of a three-phase permanent magnet synchronous motor according to claim 3, characterized in that: Step S1 specifically includes the following steps: S11. Set the acquisition time interval as Δt, and the rotation angle under the time interval Δt is Δθ. Then the actual speed of the three-phase permanent magnet synchronous motor to be monitored S12. Set the target rotational speed to ω ref , calculate the rotational speed difference x between the target rotational speed and the actual rotational speed, where x = ω ref - ω m ; S13. Input the rotational speed difference x into the resonant sliding mode controller to calculate the q-axis target current component i q ; S131. Considering the second harmonic torque disturbance caused by the high-resistance fault, construct the mechanical equation of the three-phase permanent magnet synchronous motor to be monitored: Where K t represents the torque constant; T L represents the load torque; B represents the friction coefficient; ω m represents the mechanical angular velocity of the three-phase permanent magnet synchronous motor to be monitored; ΔTsin(2ω e t) represents the double-frequency torque disturbance caused by the high-resistance connection fault; ω e represents the electrical angular velocity of the three-phase permanent magnet synchronous motor to be monitored; J represents the moment of inertia; S132. Input the speed difference x into the resonant sliding mode controller. Considering the second harmonic disturbance component caused by the high-resistance fault, introduce a resonant term in the sliding mode surface and design the sliding mode surface function: S = x + c∫x + K r G R x(2); where S represents the sliding mode surface function; c represents the integral coefficient; K r represents the resonance coefficient; G R represents the resonance function; Among them, where ω r represents the double fundamental frequency, and ω r = 2ω e , ω c represents the effective bandwidth of the resonance function; S133. Sliding mode control based on the exponential reaching law: In the formula, represents the derivative of the sliding mode surface function S with respect to time; both ∈ and k represent reaching law parameters; sign(·) represents the switching function; Among them, S134. Take the derivative of the sliding mode surface function to obtain: In the formula, represents the derivative of the actual rotational speed with respect to time; G RD represents the differential of the harmonic function G R . Among them, Combining equations (6), (7), and (8), we can obtain the q-axis target current component i q :

5. The method of the fault-tolerant control system for high-resistance connection faults of a three-phase permanent magnet synchronous motor according to claim 4, characterized in that: Step S2 specifically includes the following steps: S21. Use the current sensor to collect the real-time three-phase current of the three-phase permanent magnet synchronous motor to be monitored, and set the three-phase current expression of the three-phase permanent magnet synchronous motor to be monitored in the stationary coordinate system after the high-resistance connection fault occurs as follows: Where, i a , i b , i c respectively represent the currents of phase A, phase B, and phase C of the three-phase permanent magnet synchronous motor to be monitored; I + and I - respectively represent the amplitudes of the positive-sequence current and the negative-sequence current; and respectively represent the initial phases of the positive-sequence current and the negative-sequence current; ω represents the angular frequency of the three-phase permanent magnet synchronous motor to be monitored; t represents time; S22. Convert the three-phase current in the stationary coordinate system into a real-time current component in the synchronous rotating coordinate system through the Clark transformation matrix and the Park transformation matrix: In the formula, θ represents the rotation angle; From θ = ωt, abbreviate formula (11) to get: where, i sr represents the real-time current component in the synchronous rotating coordinate system; and represent the positive-sequence current amplitude and negative-sequence current amplitude on the d-axis respectively; and represent the positive-sequence current amplitude and negative-sequence current amplitude on the q-axis respectively; and and represent the second harmonic current components on the d-axis and q-axis respectively; S23. Calculate the q-axis target current i q and the d-axis target current i d and the current difference between the real-time current components in the synchronous rotating coordinate system, and input the current difference into a PI controller to generate a voltage control signal.

6. The method of the fault-tolerant control system for high-resistance connection faults of a three-phase permanent magnet synchronous motor according to claim 5, characterized in that: In step S23, use the adaptive notch filter to suppress the second harmonic. In this process, dynamically adjust the parameters of the adaptive notch filter through the LMS algorithm to track and cancel the second harmonic component in the current loop in real time; It specifically includes the following steps: Set the difference between the real-time current component \(i^{(n)}\) in the synchronous rotating coordinate system after the \(n\)th iteration and the second harmonic \(y(n)\) of the real-time current component extracted by the adaptive notch filter in the synchronous rotating coordinate system to be \(e(n)\), then we have: sr (n) and the second harmonic y(n) of the real-time current component extracted by the adaptive notch filter in the synchronous rotating coordinate system is e(n), then there is: y(n) = w1(n)sin(ω nf t) + w2(n)cos(ω nf t) (13); e(n) = i sr (n) - y(n) (14); where ω nf represents the required notch frequency, and ω nf = 2ω; both w1(n) and w2(n) represent weighting coefficients; Update \(w_1(n)\) and \(w_2(n)\) using the LMS algorithm: Where \(\mu\) represents the step size factor; \(w_1(n + 1)\) and \(w_2(n + 1)\) represent the updated weight coefficients.

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