Methods for suppressing harmonic currents in open-circuit faults of six-phase electrically excited doubly salient pole wind turbine generators

Abstract

This invention discloses a method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine, belonging to the field of motor control technology. First, based on full-order decoupling transformation fault-tolerant control, the reference value of the residual phase fault-tolerant current under a single-phase open-circuit fault in the six-phase electrically excited doubly salient pole motor is calculated. Second, the positive and negative sequence separation of the z1-z2 harmonic subplane currents of the six-phase electrically excited doubly salient pole motor is performed. Then, a proportional dual-resonant controller (PDR) is designed. Next, a positive and negative sequence rotating integrator is used to discretize the PDR. Finally, the z1-z2 harmonic subplane voltage signal generated by the PDR is used... u z1 , u z2 and α-β plane voltage signal u α , u β This generates drive signals for the converter power transistors. The invention can maintain stable system operation and effectively suppress harmonic currents when a single-phase open-circuit fault occurs in the motor.

Description

Technical Field

[0001] This invention relates to the field of wind turbine control technology, and in particular to a method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine. Background Technology

[0002] As a novel type of special reluctance motor, the electrically excited doubly salient pole motor (ESPPM) possesses advantages such as simple and reliable structure, flexible control, and good fault tolerance. It has attracted widespread attention in fields such as aviation and wind power generation. Furthermore, multiphase motors offer an effective way to improve motor fault tolerance; therefore, ESPPM exhibits excellent fault tolerance and is suitable for applications requiring high reliability. Currently, domestic and international research on fault-tolerant control of ESPPM primarily focuses on the motor's inherent fault tolerance, with limited research on fault-tolerant control technology for ESPPM, which is still in its early stages.

[0003] The invention, titled "Low Mutual Inductance Fault-Tolerant Six-Phase Bisaliency Brushless DC Motor" (China, Publication Date: May 22, 2018, Publication No.: 105449881A), discloses a fault-tolerant six-phase bisaliency brushless DC motor. It comprises a stator assembly and a rotor core arranged on the same shaft; the excitation element is linked to the stator coils of its corresponding two-phase stator windings, and the polarity of the excitation element and the linked stator windings are consistent. This achieves electrical isolation between the six-phase windings, exhibits good fault tolerance performance, and has low commutation torque ripple. However, this method requires design of the motor body, increasing cost and control complexity.

[0004] The invention, titled "Simplified Optimal Direct Current Control for Multiphase Permanent Magnet Fault-Tolerant Motors" (China, Publication Date: August 22, 2012, Publication No.: 101662257A), discloses a novel simplified optimal direct current control method for multiphase permanent magnet fault-tolerant motors. Based on the sinusoidal back EMF of the permanent magnet motor and aiming to minimize torque ripple, when an open-circuit or short-circuit fault occurs in a phase winding or power transistor of the permanent magnet fault-tolerant motor, the simplified optimal direct current control algorithm directly calculates the optimal given current for the normal phase winding, thereby compensating for the average output torque of the faulty phase and offsetting the ripple torque generated by the faulty phase, thus minimizing the torque ripple of the motor output while maintaining constant speed. However, this method does not establish a mathematical model after the fault, usually requiring offline calculation, and the current hysteresis control method is difficult to apply in high-power applications.

[0005] The invention, titled "Optimal Fault-Tolerant Control Method and System for Multiphase Motors Based on Online Current Optimization" (China, Publication Date: December 25, 2020, Publication No.: 110380667A), discloses an optimal fault-tolerant control method and system for multiphase motors based on online current optimization. This method reconstructs the mathematical model and vector space decoupling matrix after a fault, and then uses the reconstructed vectors to redistribute the current command to obtain the minimum loss current command value, thus achieving optimal fault-tolerant control of the motor current. This method can obtain the current command value with minimum loss under any load size within the maximum load range under any phase loss fault through online calculation, achieving excellent torque ripple suppression. However, this method requires reconstructing the mathematical model, and its modeling process is relatively complex, while fault switching is also quite difficult.

[0006] The invention, titled "A Multi-Phase Motor Phase-Loss Fault-Tolerant Operation Method Considering Multiple Degrees of Freedom" (China, Publication Date: April 29, 2022, Publication No.: 112910361A), discloses a multi-phase motor phase-loss fault-tolerant operation method considering multiple degrees of freedom. It mainly includes the calculation of fault-tolerant current reconstruction coefficients considering multiple degrees of freedom, a harmonic plane-based positive and negative sequence current decoupling controller using symmetrical component method, and a fundamental plane vector control strategy. This current reconstruction calculation method, in addition to the basic constraint of maintaining the magnetomotive force unchanged before and after the fault, utilizes the remaining degrees of freedom to constrain the injected current in the harmonic plane. The third harmonic plane vector trajectory is circular, and it is combined with the remaining harmonic plane degrees of freedom to perform optimization to minimize copper losses. The harmonic plane adopts a dual-PI current controller with positive and negative sequence decoupling, while the fundamental plane control method remains unchanged. This method can improve torque, reduce torque ripple, and decrease copper losses. However, this method only considers current constraints and ignores voltage constraints.

[0007] How to solve the above-mentioned technical problems is the challenge facing this invention. Summary of the Invention

[0008] The purpose of this invention is to address the technical problem that existing six-phase electrically excited doubly salient pole wind turbines ignore the presence of negative sequence current in the current harmonics when encountering a single-phase open-circuit fault, resulting in current fluctuations and affecting the stable operation of the motor. This invention proposes a method for suppressing harmonic currents during open-circuit faults in six-phase electrically excited doubly salient pole wind turbines. This invention can maintain stable system operation when a single-phase open-circuit fault occurs in the motor and effectively suppress harmonic currents, thereby improving the reliability and output performance of the power generation system.

[0009] To better achieve the above-mentioned objectives, this invention is implemented through the following technical solution: a method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine, comprising the following steps:

[0010] Step S1: Based on full-order decoupling transformation fault-tolerant control, with the constraint that the magnetomotive force remains unchanged before and after fault-tolerant operation, and with the maximum torque-current ratio as the objective, calculate the reference value of the residual phase fault-tolerant current under a single-phase open-circuit fault of a six-phase electrically excited doubly salient pole wind turbine generator.

[0011] Step S2: Based on the generalized symmetric component method, the positive and negative sequence separation of the z1-z2 harmonic subplane currents of the six-phase electrically excited doubly salient pole wind turbine is performed;

[0012] Step S3: Based on the positive and negative sequence separation of the z1-z2 harmonic subplane current in step S2, design a proportional dual-resonant controller (PDR) to suppress the fifth positive and negative sequence harmonic currents of the z1-z2 harmonic subplane of the six-phase electrically excited doubly salient pole wind turbine.

[0013] Step S4: Combine the rotation factor and use a positive and negative sequence rotating integrator (PDR) for discretization to achieve suppression of positive and negative sequence harmonic currents;

[0014] Step S5: Based on the z1-z2 harmonic subplane voltage signal generated by the proportional dual resonant controller PDR u z1 , u z2 and the α-β plane voltage signal of traditional vector control u α , u β Vector control is used to generate the drive signal for the converter power transistor.

[0015] Preferably, in step S1, when the six-phase electrically excited doubly salient pole wind turbine generator... w When a phase open-circuit fault occurs, the expression for the reference value of the remaining phase fault-tolerant current is:

[0016]

[0017] in, i a , i b , i c , i u , i v These are the armature winding currents of each remaining phase of a six-phase electrically excited doubly salient pole wind turbine generator. I m This represents the amplitude of the phase current before a fault occurs in a six-phase electrically excited doubly salient pole wind turbine generator. θ The electrical angle of the rotor of a six-phase electrically excited doubly salient pole wind turbine generator.

[0018] Preferably, in step S2, the generalized symmetric component transformation matrix...T k for:

[0019]

[0020] in, T k It is a generalized symmetric component transformation matrix. a For rotation factor, , k Let be the harmonic order; the expressions for the positive-sequence component and the negative-sequence component of the fifth harmonic after transformation are as follows:

[0021]

[0022] Mapping it to the z1-z2 harmonic subplane, the current expressions for the positive-sequence component and the negative-sequence component of the fifth harmonic are as follows:

[0023] ;

[0024] in, i 5+ This represents the positive-sequence component of the fifth harmonic. i 5- This represents the negative sequence component of the fifth harmonic. j The imaginary unit, i p1 , i p2 Let be the real and imaginary parts of the orthogonal component. i n1 , i n2 For the real and imaginary parts of the negative-order component.

[0025] Preferably, in step S3, the transfer function of the proportional dual resonant controller (PDR) is designed as follows:

[0026] ;

[0027] in, G PDR ( s ) represents the transfer function of the proportional dual resonant controller (PDR). K p For proportional gain; K r+ For positive sequence resonant gain, K r- To achieve negative sequence resonant gain, adjust... K r+ , K r- To achieve independent control of positive and negative order components; ω cThis refers to the system bandwidth frequency; s The differential factor; k For harmonic order; ω + The resonant frequency of the positive sequence component of the current harmonic. ω - It is the resonant frequency of the negative sequence component of the current harmonic.

[0028] Preferably, in step S4, the transfer functions of the positive and negative order rotating integrators are respectively:

[0029] ;

[0030] ;

[0031] in, G + ( z ) is the transfer function of the positive-sequence rotating integrator. G - ( z ) is the transfer function of the negative-order rotating integrator. z -1 Indicates unit delay, The rotation factor is for the positive order. The rotation factor is negative. ω e Electric angular velocity, T The sampling period;

[0032] Discretized proportional dual resonant controller PDR transfer function G PDR The expression for (z) is:

[0033] .

[0034] Preferably, step S5 further includes the transformation matrix from the natural coordinate system to the fundamental subplane, the harmonic subplane, and the zero-order space subplane, which is:

[0035] .

[0036] T 6s It is the vector space decoupling transformation matrix.

[0037] By following steps S1-S5 above, the harmonic current suppression during open-circuit faults of the six-phase electrically excited doubly salient pole wind turbine can be achieved, enabling the six-phase electrically excited doubly salient pole wind turbine to achieve stable operation after a single-phase open-circuit fault.

[0038] To achieve the above-mentioned objectives, the present invention also provides a harmonic current suppression system for open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator, the system comprising:

[0039] A six-phase electrically excited doubly salient pole wind turbine generator, two three-phase full-bridge main power converters, and an asymmetrical half-bridge excitation power converter; the six-phase armature winding electrical control drive terminal of the six-phase electrically excited doubly salient pole motor is connected to the wiring terminal of the full-bridge main power converter, and the excitation winding electrical control drive terminal is connected to the wiring terminal of the asymmetrical half-bridge excitation power converter.

[0040] Meanwhile, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed, it implements the steps of the method of the present invention.

[0041] In addition, the present invention also provides a computer-readable storage medium having a computer program stored thereon, the computer program being configured to implement the steps of the method of the present invention when invoked by a processor.

[0042] Finally, the present invention also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the method of the present invention.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] (1) The method of the present invention has high control accuracy and good harmonic suppression effect: by combining the proportional dual resonant controller with the generalized symmetrical component method, it realizes zero steady-state error tracking and precise suppression of AC harmonics (especially negative sequence current), overcoming the limitations of traditional PI control.

[0045] (2) The method of the present invention is highly versatile and easy to design: the method does not require reconstruction of the mathematical model of the motor and the decoupling matrix, which significantly simplifies the design process and can be applied to symmetrical multiphase motors with different numbers of phases and neutral point connection methods.

[0046] (3) The system performance of the method of the present invention is significantly improved: it effectively suppresses the harmonic current and current fluctuation after the fault, thereby reducing motor loss and improving the system efficiency and stability during fault-tolerant operation. Attached Figure Description

[0047] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0048] Figure 1 This is a system control block diagram of the present invention.

[0049] Figure 2 This invention relates to a topology diagram of a six-phase electrically excited doubly salient pole wind turbine drive circuit.

[0050] Figure 3 This invention relates to a cross-sectional view of a 12 / 10 pole six-phase electrically excited doubly salient pole wind turbine.

[0051] Figure 4 This is a schematic diagram of the generalized symmetric component method involved in this invention.

[0052] Figure 5 This invention relates to a positive and negative sequence separation diagram of the fifth current harmonic.

[0053] Figure 6 This is a graph showing the motor current and speed curves using the control strategy of this invention.

[0054] Figure 7 This is a schematic diagram showing the comparison of current harmonics between the control method of this invention and the traditional control strategy. Detailed Implementation

[0055] 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. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0056] Example 1: The system control block diagram of the method of the present invention is as follows. Figure 1 As shown, where, Figure 1 middle, and These represent the reference angular velocity and the actual angular velocity of a six-phase electrically excited doubly salient pole wind turbine, respectively. i d * and i d These represent the reference and actual values ​​of the d-axis current, respectively. i q * and i q These represent the reference and actual values ​​of the q-axis current, respectively. i z1 * and i z2 * These represent the reference values ​​for the currents along the z1 and z2 axes, respectively. i z1 , i z1 + and i z1 - These represent the z1-axis current and its positive-sequence and negative-sequence components, respectively. i z2 , i z2+ and i z2 - These represent the z2-axis current and its positive-sequence and negative-sequence components, respectively. θ Indicates the rotor position angle. u d and u q These represent the reference voltages for the d and q axes, respectively. u α and u β These represent the reference voltages for the α and β axes, respectively. i abc and i uvw These represent the phase currents of phases ABC and UVW, respectively. u z1 and u z2 These represent the voltages of axes z1 and z2, respectively; this embodiment involves a six-phase electrically excited doubly salient pole wind turbine drive circuit. Figure 2 As shown, it includes: a six-phase electrically excited doubly salient pole wind turbine generator, two three-phase full-bridge main power converters, and an asymmetrical half-bridge excitation power converter. The six-phase armature windings of the six-phase electrically excited doubly salient pole wind turbine generator are connected to the full-bridge main power converter, and the excitation windings are connected to the asymmetrical half-bridge excitation power converter; wherein, Figure 2 middle, U dc This refers to the DC bus voltage of the six-phase full-bridge power converter. U f T1…T8 represents the DC bus voltage of the unbalanced half-bridge power converter, T1…T8 represents the IGBT transistor numbers in the power converter, and D1…D…D… 10 It's the diode number. i a , i b , i c , i u , i v , i w It is the armature winding current. i f It is the magnetizing current. L f It is the magnetizing winding inductance. L a , L b , L c , L u , Lv , L w It is the armature winding inductance. e f This is the back EMF of the excitation winding. e a , e b , e c , e u , e v , e w It is the back EMF of the armature winding. The cross-sectional structure of the six-phase electrically excited doubly salient pole motor is as follows: Figure 3 As shown. Figure 4 This is a schematic diagram of the positive-order, negative-order, and zero-order components represented using the symmetric component method, where... Figure 4 middle, I a1 I a2 I a0 These are the positive-sequence, negative-sequence, and zero-sequence components of the A-phase current, I b1 I b2 I b0 These are the positive-sequence, negative-sequence, and zero-sequence components I of the B-phase current. c1 I c2 I c0 These represent the positive-sequence, negative-sequence, and zero-sequence components of the C-phase current, respectively. The z1-z2 harmonic sub-plane currents are separated into positive and negative sequences as follows: Figure 5 As shown. Figure 5 middle, i p1 , i p2 Let be the real and imaginary parts of the orthogonal component. i n1 , i n2 These represent the real and imaginary parts of the negative-sequence component. The current and speed waveforms of a six-phase electrically excited doubly salient pole wind turbine generator employing the control strategy of this invention are shown below. Figure 6 As shown. Among them. and These represent the positive and negative sequence components of the 5th current harmonics in the z1 subplane. A comparison of the harmonic content of the control strategy of this invention with that of traditional control strategies is shown below. Figure 7 As shown.

[0057] This embodiment provides a method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator, which specifically includes the following steps:

[0058] Step S1: Based on full-order decoupling transformation fault-tolerant control, with the constraint that the magnetomotive force remains unchanged before and after fault-tolerant operation, and with the maximum torque-current ratio as the objective, calculate the reference value of the residual phase fault-tolerant current under a single-phase open-circuit fault of a six-phase electrically excited doubly salient pole wind turbine generator.

[0059] Step S2: Use the generalized symmetrical component method to separate the positive and negative sequence of the z1-z2 harmonic subplane currents of the six-phase electrically excited doubly salient pole wind turbine generator;

[0060] Step S3: Based on the positive and negative sequence separation results of the z1-z2 harmonic subplane currents of the six-phase electrically excited doubly salient pole wind turbine in step S2, design a proportional dual resonant controller (PDR) to suppress the fifth positive and negative sequence harmonic currents of the z1-z2 harmonic subplane of the six-phase electrically excited doubly salient pole wind turbine.

[0061] Step S4: Combining the rotation factor, a positive and negative sequence rotating integrator is used to discretize the proportional dual resonant controller PDR to suppress the positive and negative sequence harmonic currents.

[0062] Step S5: Based on the z1-z2 harmonic subplane voltage signals of the six-phase electrically excited doubly salient pole wind turbine generator generated by the proportional dual-resonant controller PDR. u z1 , u z2 and the α-β plane voltage signal of traditional vector control u α , u β Vector control is used to generate the drive signal for the converter power transistor.

[0063] Specifically, in step S1, when the six-phase electrically excited doubly salient pole wind turbine generator... w When a phase open-circuit fault occurs, the expression for the reference value of the remaining phase fault-tolerant current is:

[0064] ;

[0065] in, i a , i b , i c , i u , i v These are the armature winding currents of each remaining phase of a six-phase electrically excited doubly salient pole wind turbine generator. I m This represents the amplitude of the phase current before a fault occurs in a six-phase electrically excited doubly salient pole wind turbine generator. θ The electrical angle of the rotor of a six-phase electrically excited doubly salient pole wind turbine generator.

[0066] Specifically, in step S2, the generalized symmetric component transformation matrix T k for:

[0067] ;

[0068] in, T k It is a generalized symmetric component transformation matrix. a For rotation factor, , k Let be the harmonic order; the expressions for the positive-sequence component and the negative-sequence component of the fifth harmonic after transformation are as follows:

[0069] ;

[0070] Mapping it to the z1-z2 harmonic subplane, the current expressions for the positive-sequence component and the negative-sequence component of the fifth harmonic are as follows:

[0071] ;

[0072] in, i 5+ This represents the positive-sequence component of the fifth harmonic. i 5- This represents the negative sequence component of the fifth harmonic. j The imaginary unit, i p1 , i p2 These are the real and imaginary parts of the positive-order component, respectively. i n1 , i n2 These are the real and imaginary parts of the negative-order component, respectively.

[0073] Specifically, in step S3, the transfer function of the proportional dual resonant controller PDR is designed as follows:

[0074] ;

[0075] in, G PDR ( s ) represents the transfer function of the proportional dual resonant controller (PDR). K p For proportional gain; K r+ For positive sequence resonant gain, K r- To achieve negative sequence resonant gain, adjust... K r+ , K r-To achieve independent control of positive and negative order components; ω c This refers to the system bandwidth frequency; s The differential factor; k For harmonic order; ω + The resonant frequency of the positive sequence component of the current harmonic. ω - It is the resonant frequency of the negative sequence component of the current harmonic.

[0076] Specifically, in step S4, the transfer functions of the positive and negative order rotating integrators are as follows:

[0077] ;

[0078] ;

[0079] in, G + ( z ) is the transfer function of the positive-sequence rotating integrator. G - ( z ) is the transfer function of the negative-order rotating integrator. z -1 Indicates unit delay, The rotation factor is for the positive order. The rotation factor is negative. ω e Electric angular velocity, T The sampling period;

[0080] Discretized proportional dual resonant controller PDR transfer function G PDR The expression for (z) is:

[0081] .

[0082] Specifically, step S5 further includes the transformation matrix from the natural coordinate system to the fundamental subplane, the harmonic subplane, and the zero-order space subplane, which is:

[0083] ;

[0084] T 6s It is the vector space decoupling transformation matrix.

[0085] Therefore, by using the above steps S1-S5, the harmonic current suppression of open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine can be achieved, enabling the six-phase electrically excited doubly salient pole wind turbine to achieve stable operation after a single-phase open-circuit fault.

[0086] Example 2: This example proposes a harmonic current suppression system for open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator, comprising:

[0087] The system consists of a six-phase electrically excited doubly salient pole wind turbine, two three-phase full-bridge main power converters, and an asymmetrical half-bridge excitation power converter. The six-phase armature winding of the six-phase electrically excited doubly salient pole motor is connected to the wiring terminals of the full-bridge main power converter, and the excitation winding is connected to the wiring terminals of the asymmetrical half-bridge excitation power converter.

[0088] Example 3: This example proposes an electronic system, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method steps of the present invention.

[0089] Example 4: This example proposes a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the steps of the method described in this invention, which will not be repeated here.

[0090] Example 5: This example proposes a computer program product, including a computer program / instructions. When the computer program / instructions are executed by a processor, they implement the steps of the method described in this invention, which will not be repeated here.

[0091] It should be noted that the processing flow of embodiments 2-5 corresponds to the specific steps of the method provided in embodiment 1 of the present invention, and has the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in this embodiment can be found in the method provided in embodiment 1 of the present invention.

[0092] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0093] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention. The actual structure and method are not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs shall fall within the protection scope of the present invention.

Claims

1. A method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator, characterized in that, Includes the following steps: Step S1: Based on full-order decoupling transformation fault-tolerant control, with the constraint that the magnetomotive force remains unchanged before and after fault-tolerant operation, and with the maximum torque-current ratio as the objective, calculate the reference value of the residual phase fault-tolerant current under a single-phase open-circuit fault of a six-phase electrically excited doubly salient pole wind turbine generator. Step S2: Use the generalized symmetrical component method to separate the positive and negative sequence of the z1-z2 harmonic subplane currents of the six-phase electrically excited doubly salient pole wind turbine generator; Step S3: Based on the positive and negative sequence separation results of the z1-z2 harmonic subplane currents of the six-phase electrically excited doubly salient pole wind turbine in step S2, design a proportional dual resonant controller (PDR) to suppress the fifth positive and negative sequence harmonic currents of the z1-z2 harmonic subplane of the six-phase electrically excited doubly salient pole wind turbine. Step S4: Combining the rotation factor, a positive and negative sequence rotating integrator is used to discretize the proportional dual resonant controller PDR to suppress the positive and negative sequence harmonic currents. Step S5: Based on the z1-z2 harmonic subplane voltage signals of the six-phase electrically excited doubly salient pole wind turbine generator generated by the proportional dual-resonant controller PDR. u z1 , u z2 and the α-β plane voltage signal of traditional vector control u α , u β Vector control is used to generate the drive signal for the converter power transistor.

2. The method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator according to claim 1, characterized in that, In step S1, when the six-phase electrically excited doubly salient pole wind turbine generator... w When a phase open-circuit fault occurs, the expression for the reference value of the remaining phase fault-tolerant current is: ； in, i a , i b , i c , i u , i v These are the armature winding currents of each remaining phase of a six-phase electrically excited doubly salient pole wind turbine generator. I m This represents the amplitude of the phase current before a fault occurs in a six-phase electrically excited doubly salient pole wind turbine generator. θ The electrical angle of the rotor of a six-phase electrically excited doubly salient pole wind turbine generator.

3. The method for suppressing harmonic currents in an open-circuit fault of a six-phase electrically excited doubly salient pole wind turbine generator according to claim 2, characterized in that, In step S2, the generalized symmetric component transformation matrix T k for: ； in, T k It is a generalized symmetric component transformation matrix. a For rotation factor, , k Let be the harmonic order; the expressions for the positive-sequence component and the negative-sequence component of the fifth harmonic after transformation are as follows: ； Mapping it to the z1-z2 harmonic subplane, the current expressions for the positive-sequence component and the negative-sequence component of the fifth harmonic are as follows: ； in, i 5+ This represents the positive-sequence component of the fifth harmonic. i 5- This represents the negative sequence component of the fifth harmonic. j The imaginary unit, i p1 , i p2 These are the real and imaginary parts of the positive-order component, respectively. i n1 , i n2 These are the real and imaginary parts of the negative-order component, respectively.

4. The method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator according to claim 3, characterized in that, In step S3, the transfer function of the proportional dual resonant controller PDR is designed as follows: ； in, G PDR ( s ) represents the transfer function of the proportional dual resonant controller (PDR). K p For proportional gain; K r+ For positive sequence resonant gain, K r- To achieve negative sequence resonant gain, adjust... K r+ , K r- To achieve independent control of positive and negative order components; ω c This refers to the system bandwidth frequency; s The differential factor; k For harmonic order; ω + The resonant frequency of the positive sequence component of the current harmonic. ω - It is the resonant frequency of the negative sequence component of the current harmonic.

5. A method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator according to claim 4, characterized in that, In step S4, the transfer functions of the positive and negative order rotating integrators are respectively: ； ； in, G + ( z ) is the transfer function of the positive-sequence rotating integrator. G - ( z ) is the transfer function of the negative-order rotating integrator. z -1 Indicates unit delay, The rotation factor is for the positive order. The rotation factor is negative. ω e Electric angular velocity, T The sampling period; Discretized proportional dual resonant controller PDR transfer function G PDR The expression for (z) is: 。 6. The method for suppressing harmonic currents during open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator according to claim 5, characterized in that, Step S5 further includes the transformation matrices from the natural coordinate system to the fundamental subplane, harmonic subplane, and zero-order space subplane, which are: ； T 6s It is the vector space decoupling transformation matrix.

7. A harmonic current suppression system for open-circuit faults in a six-phase electrically excited doubly salient pole wind turbine generator, characterized in that, The system implements the steps of the method as described in any one of claims 1 to 6, including: A six-phase electrically excited doubly salient pole wind turbine generator, two three-phase full-bridge main power converters, and an asymmetrical half-bridge excitation power converter; the six-phase armature winding electrical control drive terminal of the six-phase electrically excited doubly salient pole motor is connected to the wiring terminal of the full-bridge main power converter, and the excitation winding electrical control drive terminal is connected to the wiring terminal of the asymmetrical half-bridge excitation power converter.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed, it implements the steps of the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program is configured to implement the steps of the method according to any one of claims 1 to 6 when invoked by a processor.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1 to 6.

Images