A self-healing fault-tolerant control method, device and system for an induction motor drive system

Abstract

This invention discloses a self-healing fault-tolerant control method, apparatus, and system for an induction motor drive system. The method calculates a mode switching flag and a fault diagnosis flag at each instant. The system then calculates the voltage vector in the appropriate mode based on these flags to control the motor. Since a power switch fault only affects half a current cycle, the additional healthy power switch on the same bridge arm can continue to operate normally in the other half of the cycle. Within one current cycle, the system alternates between healthy mode and fault-tolerant mode, significantly reducing torque loss caused by power switch faults. Furthermore, because the mode switching flag is calculated twice at each instant, even if a misdiagnosis causes an error in the calculation, it will be corrected by subsequent calculations. This avoids misdiagnosis causing the motor to continuously operate in an inappropriate fault-tolerant mode, thereby improving system reliability.

Description

Technical Field

[0001] This invention belongs to the field of electric motors, and more specifically, relates to a self-healing fault-tolerant control method, device, and system for an induction motor drive system. Background Technology

[0002] Motor drive systems are widely used in industrial manufacturing, aerospace, transportation, and other fields, with induction motors being the vast majority. In recent years, the demand for the safety and reliability of motor drive systems has been increasing in many applications. As the core component for energy conversion in motor drive systems, studying the fault tolerance of inverters after power switch failures is of great significance.

[0003] Currently, most fault-tolerance methods require additional hardware, which increases both cost and unreliability.

[0004] Therefore, how to achieve fault tolerance of the power switch in an induction motor drive system without adding extra hardware is a problem that urgently needs to be solved. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a self-healing fault-tolerant control method, device, and system for an induction motor drive system, aiming to achieve fault tolerance of its power switch without hardware structure switching.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a self-healing fault-tolerant control method for an induction motor drive system is provided, comprising:

[0007] S1, determine the mode judgment flag quantity F based on the three-phase deviation components of the reference stator flux linkage of the induction motor at the previous moment and the stator flux linkage at the current moment. s and fault location marker quantity F l ;

[0008] Wherein, if any one of the three-phase deviation components is greater than a preset threshold, then F s The value of F is updated to 1. l The value of is updated to x, where x is the phase with polarity opposite to the other two phases in the three-phase deviation component, x∈(a,b,c). If it does not exist, then F s and F l The value remains unchanged;

[0009] S2, if F s =1, then according to F l The value of F is used to calculate the reference stator flux linkage at the current moment in fault-tolerant mode, in order to obtain the voltage vector in fault-tolerant mode; if F s =0, then calculate the reference stator flux linkage at the current moment in health mode to obtain the voltage vector in health mode;

[0010] S3, determine whether the deviation between the amplitude of the reference stator flux linkage at the current moment obtained in S2 and the amplitude of the rated stator flux linkage is less than a preset threshold. If so, then set F... s The value of F is updated to 0; otherwise, F is updated to 0. s The value remains unchanged.

[0011] According to a second aspect of the present invention, a self-healing fault-tolerant control device for an induction motor drive system is provided, comprising:

[0012] The first processing module is used to determine the mode judgment flag F based on the three-phase deviation components of the reference stator flux linkage of the induction motor at the previous moment and the stator flux linkage at the current moment. s and fault location marker quantity F l ;

[0013] Wherein, if any one of the three-phase deviation components is greater than a preset threshold, then F s The value of F is updated to 1. l The value of is updated to x, where x is the phase with polarity opposite to the other two phases in the three-phase deviation component, x∈(a,b,c). If it does not exist, then F s and F l The value remains unchanged;

[0014] The second processing module is used if F s =1, then according to F l The value of F is used to calculate the reference stator flux linkage at the current moment in fault-tolerant mode, in order to obtain the voltage vector in fault-tolerant mode; if F s =0, then calculate the reference stator flux linkage at the current moment in health mode to obtain the voltage vector in health mode;

[0015] The third processing module is used to determine whether the deviation between the amplitude of the reference stator flux linkage at the current moment and the amplitude of the rated stator flux linkage is less than a preset threshold. If so, then F... s The value of F is updated to 0; otherwise, F is updated to 0. s The value remains unchanged.

[0016] According to a third aspect of the present invention, a self-healing fault-tolerant control system for an induction motor drive system is provided, comprising: a computer-readable storage medium and a processor;

[0017] The computer-readable storage medium is used to store executable instructions;

[0018] The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the method as described in the first aspect.

[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0020] The self-healing fault-tolerant control method for an induction motor drive system provided by this invention can achieve self-healing fault tolerance of the induction motor drive system by adjusting only the motor control algorithm without adding any hardware or switching the hardware structure. Specifically, this method calculates a mode switching flag and a fault diagnosis flag at each moment. The system will then determine the mode based on the mode switching flag (i.e., the mode judgment flag F). s ) and fault diagnosis markers (i.e., fault location markers F) l The voltage vector in the appropriate mode is calculated to control the motor. Since a power switch failure only affects half a current cycle, the additional healthy power switch in the same bridge arm can continue to operate normally in the other half of the cycle. Within a current cycle, the system alternates between healthy mode and fault-tolerant mode, greatly reducing torque loss caused by power switch failure. In addition, since the mode switching flag is calculated twice at each moment, even if a mode switching flag is miscalculated due to a fault misdiagnosis, it will be corrected by subsequent calculations. This avoids the motor operating in an inappropriate fault-tolerant mode due to misdiagnosis, thereby improving system reliability. Attached Figure Description

[0021] Figure 1 This is one of the flowcharts of the self-healing fault-tolerant control method for an induction motor drive system provided in an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of a two-level three-phase induction motor drive system;

[0023] Figure 3 The second flowchart illustrates the self-healing fault-tolerant control method for an induction motor drive system provided in this embodiment of the invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] This invention provides a self-healing fault-tolerant control method for an induction motor drive system, such as... Figure 1 As shown, it includes:

[0026] S1, based on the three-phase deviation component Δψ of the reference stator flux linkage of the induction motor at the previous moment and the stator flux linkage at the current moment. sa ,Δψsb ,Δψ sc Determine the pattern judgment flag quantity F s and fault location marker quantity F l ;

[0027] If any one of the three-phase deviation components is greater than a preset threshold, then the mode judgment flag F is set to... s The value is updated to 1, and the fault location flag value F l The value of is updated to x, where x is the phase with polarity opposite to the other two phases in the three-phase deviation component, x∈(a,b,c); if it does not exist, then F s and F l The value remains unchanged.

[0028] Understandably, at the initial moment, referring to the stator flux linkage, F s F l The initial values ​​of all are 0.

[0029] Specifically, if Δψ sa ,Δψ sb ,Δψ sc There exists any value greater than the fault diagnosis threshold (i.e., the preset threshold) T. z Then F s If it is 1, then Fs remains unchanged; in F s When Δψ is 1, if Δψ sa ,Δψ sb ,Δψ sc If one phase in F has a polarity opposite to the other two phases, then F l The corresponding subscript (a, b, or c).

[0030] Understandably, theoretically speaking, when F s When Δψ is 1, sa ,Δψ sb ,Δψ sc There must be one phase whose polarity is opposite to the other two. However, due to external factors such as sampling errors, there may be a situation where one phase does not have a polarity opposite to the other two. If this situation occurs, then F is maintained. l The value remains unchanged.

[0031] Furthermore, the formula for calculating the three-phase deviation components between the reference stator flux at the previous moment and the stator flux at the current moment is as follows:

[0032]

[0033] Where, ψ sα *,k-1 Let ψ be the real component of the reference stator flux linkage at the previous moment. sβ *,k-1Let ψ be the imaginary component of the reference stator flux linkage at the previous moment. sα k Let ψ be the real component of the stator flux linkage at the current moment. sβ k This represents the imaginary component of the stator flux linkage at the current moment.

[0034] S2, if F s =1, then according to F l The value of F is used to calculate the reference stator flux linkage at the current moment in fault-tolerant mode, in order to obtain the voltage vector in fault-tolerant mode; if F s =0, then calculate the reference stator flux linkage at the current moment in the health mode to obtain the voltage vector in the health mode.

[0035] That is, the voltage vector of the corresponding mode is selected based on the mode judgment flag, if F s If F is 1, select the voltage vector in fault-tolerant mode; if F s If the value is 0, select the voltage vector in health mode.

[0036] Furthermore, voltage vector Where, ψ s k and i s k These are the stator flux linkage and stator current at the current moment, respectively, R s T is the stator resistance. s The switching cycle.

[0037] The voltage vector in healthy mode is calculated based on the motor reference torque, the rotor flux linkage of the motor at the next moment, the motor current vector at the current moment, and the stator flux linkage, combined with the rated stator flux linkage amplitude. The voltage vector in fault-tolerant mode is calculated by combining the fault location marker.

[0038] Understandably, regardless of whether it's health mode or fault-tolerant mode, the formula for calculating the voltage vector is the same. However, in both healthy mode and fault-tolerant mode, the reference stator flux linkage ψ at the current moment... s * The calculation formulas are different, as follows:

[0039] In health mode, the relationships between the motor reference torque, the rotor flux linkage of the motor at the next moment, the motor current vector at the current moment, the stator flux linkage at the current moment, the rated stator flux linkage amplitude, and the voltage vector are as follows:

[0040] ψ s * =ψ m * ·e j∠ψs* ;

[0041] Where, ψm * The rated stator flux linkage amplitude, ∠ψ s * For reference stator flux linkage angle, |ψ r k+1 | represents the rotor flux linkage amplitude at the next moment, ∠ψ r k+1 The rotor flux angle at the next moment. n p L is the number of magnetic pole pairs. m Mutual inductance between motors;

[0042] In fault-tolerant mode, the relationship between the motor reference torque, the rotor flux linkage of the motor at the next moment, the motor current vector at the current moment, the stator flux linkage at the current moment, the fault location flag, and the voltage vector is as follows:

[0043] If F l =a, then:

[0044] If F l =b, then:

[0045]

[0046] If F l =c, then:

[0047]

[0048] in, τ σ =1 / (λL) r R σ ), τ r =L r / R r , ψ s k Let i be the stator flux linkage at the current moment. s k T is the stator current at the current moment. e * n is the reference torque for the motor. p L is the number of magnetic pole pairs. m For motor mutual inductance, L s For stator inductance, L r R is the rotor inductance. s R is the stator resistance. r For rotor resistance, This represents the real component of the stator flux linkage at the next moment. This represents the imaginary component of the stator flux linkage at the next moment. This represents the real component of the stator flux linkage at the current moment. Let T be the imaginary component of the stator flux linkage at the current moment. s For the switching cycle, This represents the real component of the current vector at the current moment. ω is the imaginary component of the current vector at the current moment. r This represents the motor speed.

[0049] Specifically, the reference torque of the motor is calculated based on the rotational speed and reference speed of the induction motor. Based on the received three-phase current and rotational speed of the motor at the current moment, the current vector, rotor flux linkage and stator flux linkage of the motor at the current moment are calculated, and the rotor flux linkage of the motor at the next moment is predicted.

[0050] Specifically, the relationship between the motor speed and the reference speed and the motor reference torque is as follows:

[0051] T e * =k p (ω r * -ω r )+k i ·∫(ω r * -ω r )

[0052] Where, ω r * For reference rotational speed, ω r T is the motor speed. e * k is the reference torque for the motor. p k i It is the gain factor.

[0053] The relationship between the motor's current vector and its three-phase current at the current moment is as follows:

[0054]

[0055] Among them, i s k Let i be the current vector at the current moment. a k i b k i c k This represents the three-phase current of each motor at the current moment.

[0056] The rotor flux linkage and stator flux linkage of each motor at the current moment are:

[0057]

[0058]

[0059] Where, τ r =L r / R r k r =L m / L r , ψ r k Let ψ be the rotor flux linkage at the current moment. s k Let L be the stator flux linkage at the current moment. r ,L s ,L m Represents rotor inductance, stator inductance, mutual inductance, and T. s R represents the sampling period. r Indicates rotor resistance, i s k ω represents the current vector of each motor at the current moment. r This represents the motor speed.

[0060] The rotor flux linkage of the motor at the next moment will be:

[0061]

[0062] Where, ψ r k+1 For the rotor flux linkage at the next moment, ω r This represents the motor speed.

[0063] S3, determine whether the deviation between the amplitude of the reference stator flux linkage at the current moment and the amplitude of the rated stator flux linkage is less than a preset threshold. If so, then set F... s The value of F is updated to 0; otherwise, F is updated to 0. s The value remains unchanged.

[0064] At each time step, S1, S2, and S3 are executed sequentially.

[0065] Specifically, the relationship between the deviation between the current calculated reference stator flux linkage amplitude and the rated stator flux linkage amplitude and the mode judgment flag is as follows:

[0066]

[0067] Among them, |ψ s * |For reference stator flux linkage amplitude This is the rated stator flux linkage amplitude.

[0068] Furthermore, the induction motor is a three-phase induction motor, and the induction motor drive system is a multi-level three-phase induction motor drive system.

[0069] Taking a two-level three-phase induction motor drive system as an example, such as Figure 2 As shown, the two-level three-phase induction motor drive system includes DC capacitor bridge arm O, power bridge arm a, power bridge arm b, power bridge arm c, and induction motor. The system outputs speed and three-phase current to the outside and inputs voltage vector to control the motor internally.

[0070] The value of the preset threshold is affected by the accuracy of flux linkage estimation and the magnitude of flux linkage amplitude. Generally, it is acceptable as long as the changes before and after the fault can be distinguished. Preferably, the value range of the preset threshold is 0.01-0.1.

[0071] like Figure 3 As shown, the method provided by this invention includes: calculating the voltage vector in healthy mode based on the three-phase current and speed of the motor at the current moment, combined with the rated stator flux linkage amplitude; calculating the voltage vector in fault-tolerant mode based on the fault location flag; selecting an appropriate voltage vector based on the mode switching flag; obtaining the mode switching flag and the fault location flag based on the deviation between the reference stator flux linkage calculated at the previous moment and the stator flux linkage at the current moment; obtaining the mode switching flag based on the deviation between the reference stator flux linkage amplitude calculated at the current moment and the rated stator flux linkage amplitude; this invention achieves self-healing fault tolerance of the induction motor drive system after a power switch failure by alternating between the two modes in each current cycle, without the need for hardware switching, greatly improving reliability.

[0072] This invention provides a self-healing fault-tolerant control device for an induction motor drive system, comprising:

[0073] The first processing module is used to determine the three-phase deviation component Δψ between the reference stator flux linkage of the induction motor at the previous moment and the stator flux linkage at the current moment. sa ,Δψ sb ,Δψ sc Determine the pattern judgment flag quantity F s and fault location marker quantity F l ;

[0074] If any one of the three-phase deviation components is greater than a preset threshold, then the mode judgment flag F is set to... s The value is updated to 1, and the fault location flag value F l The value of is updated to x, where x is the phase with polarity opposite to the other two phases in the three-phase deviation component, x∈(a,b,c). If it does not exist, then F s and F l The value remains unchanged;

[0075] The second processing module is used if F s=1, then calculate the reference stator flux linkage at the current moment in fault-tolerant mode to obtain the voltage vector in fault-tolerant mode; if F s =0, then calculate the reference stator flux linkage at the current moment in health mode to obtain the voltage vector in health mode;

[0076] The third processing module is used to determine whether the deviation between the amplitude of the reference stator flux linkage at the current moment and the amplitude of the rated stator flux linkage is less than a preset threshold. If so, then F... s The value of F is updated to 0; otherwise, F is updated to 0. s The value remains unchanged.

[0077] This invention provides a self-healing fault-tolerant control system for an induction motor drive system, comprising: a computer-readable storage medium and a processor;

[0078] The computer-readable storage medium is used to store executable instructions;

[0079] The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the method as described in any of the above embodiments.

[0080] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-healing fault-tolerant control method of an induction motor drive system, characterized by, include: S1, determine the mode judgment flag quantity based on the three-phase deviation components of the reference stator flux linkage of the induction motor at the previous moment and the stator flux linkage at the current moment. and fault location marker quantity ; Wherein, if any one of the three-phase deviation components is greater than a preset threshold, then... The value is updated to 1. The value is updated to x , x The phase with polarity opposite to the other two in the three-phase deviation components ，x ∈( a,b,c If it does not exist, then and The value remains unchanged; S2, if According to The value is used to calculate the reference stator flux linkage at the current moment in fault-tolerant mode to obtain the voltage vector in fault-tolerant mode; if Then, calculate the reference stator flux linkage at the current moment in the health mode to obtain the voltage vector in the health mode; S3, determine whether the deviation between the amplitude of the reference stator flux linkage at the current moment obtained in S2 and the amplitude of the rated stator flux linkage is less than a preset threshold. If so, then... The value is updated to 0; otherwise, the value is updated to 0. The value remains unchanged; Wherein, voltage vector ;in, and These are the stator flux linkage and stator current at the current moment, respectively. For stator resistance, For switching cycles; Using the current reference stator flux linkage, in health mode, , This is the rated stator flux linkage amplitude. For reference stator flux linkage angle, The rotor flux linkage amplitude at the next moment. The rotor flux angle at the next moment. , The number of magnetic pole pairs Mutual inductance between motors; In fault-tolerant mode, if ,but: ; like ,but: ； like ,but: ； in, , , , , , The stator flux linkage at the current moment, The current is the stator current at the current moment. This is the reference torque for the motor. The number of magnetic pole pairs For mutual inductance of motors, For stator inductance, For rotor inductance, For stator resistance, For rotor resistance, This represents the real component of the stator flux linkage at the next moment. This represents the imaginary component of the stator flux linkage at the next moment. This represents the real component of the stator flux linkage at the current moment. This represents the imaginary component of the stator flux linkage at the current moment. For the switching cycle, This represents the real component of the current vector at the current moment. This is the imaginary component of the current vector at the current moment. This represents the motor speed.

2. The method as described in claim 1, characterized in that, The formula for calculating the three-phase deviation components between the reference stator flux linkage at the previous moment and the stator flux linkage at the current moment is as follows: ； in, This represents the real component of the reference stator flux linkage from the previous moment. This is the imaginary component of the reference stator flux linkage from the previous moment. Let be the real component of the stator flux linkage at the current moment. This represents the imaginary component of the stator flux linkage at the current moment.

3. The method as described in claim 1, characterized in that, The induction motor is a three-phase induction motor.

4. The method as described in claim 1 or 3, characterized in that, The induction motor drive system is a multi-level three-phase induction motor drive system.

5. A self-healing fault-tolerant control device for an induction motor drive system, used to implement the method as described in any one of claims 1-4, characterized in that, include: The first processing module is used to determine the mode judgment flag quantity based on the three-phase deviation components of the reference stator flux linkage of the induction motor at the previous moment and the stator flux linkage at the current moment. and fault location marker quantity ; Wherein, if any one of the three-phase deviation components is greater than a preset threshold, then... The value is updated to 1. The value is updated to x , x The phase with polarity opposite to the other two in the three-phase deviation components ，x ∈( a,b,c If it does not exist, then and The value remains unchanged; The second processing module is used for... According to The value is used to calculate the reference stator flux linkage at the current moment in fault-tolerant mode to obtain the voltage vector in fault-tolerant mode; if Then, calculate the reference stator flux linkage at the current moment in the health mode to obtain the voltage vector in the health mode; The third processing module is used to determine whether the deviation between the amplitude of the reference stator flux linkage at the current moment and the amplitude of the rated stator flux linkage is less than a preset threshold. If so, then... The value is updated to 0; otherwise, the value is updated to 0. The value remains unchanged.

6. A self-healing fault-tolerant control system for an induction motor drive system, characterized in that, include: Computer-readable storage media and processors; The computer-readable storage medium is used to store executable instructions; The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the method as described in any one of claims 1-4.

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