Non-redundant fault-tolerant control method and system for parallel wind power conversion system

Abstract

The present invention provides a non-redundant fault-tolerant control method and system for a parallel wind power conversion system, which determines whether a switch tube fails. If so, the fault type is determined, otherwise the switch control instruction is determined through a model predictive control strategy; if the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty, the switch control instruction is determined through a model predictive control strategy; otherwise: determine the state health function of each switch tube; reconstruct the reference current according to the state health function of each switch tube and the current flow direction of the power grid; based on the reconstructed reference current, perform current hysteresis control to obtain the switch control instruction of each switch tube. The present invention does not need to disconnect the faulty bridge arm, but only needs to isolate the faulty switch tube, so that the remaining healthy switch tubes can be fully utilized, thereby making the life of all switch tubes in the conversion system more balanced, and improving the reliability of the offshore wind power conversion system.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-redundant fault-tolerant control, and in particular relates to a non-redundant fault-tolerant control method and system for a parallel wind power conversion system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Deep sea wind resources have great potential. They have advantages such as stable wind speed and proximity to power load centers, and have become a research hotspot in the field of wind power generation. However, due to the complexity of the environment in which they are located and the high construction costs, the development of offshore wind resources faces severe challenges. In order to overcome the above problems and improve the competitiveness of offshore wind power generation systems, the key is to increase the power generation capacity of a single wind turbine, thereby reducing the cost of power generation. To this end, the trend of using large-capacity offshore wind turbines is becoming increasingly obvious. With the steady increase in the rated power of wind turbines, a single converter can no longer meet the power requirements. Therefore, parallel operation of wind power converters is an effective way to improve the capacity and reliability of wind power generation systems.

[0004] The harsh offshore environmental conditions, high salt spray concentration, high humidity, and frequent disastrous weather seriously affect the safe operation of electrical equipment. As the capacity of wind power generation systems increases, the failure rate of wind turbines also increases. Therefore, it is particularly important to improve the reliability and availability of wind power conversion systems. The main cause of converter failure is the failure of insulated gate bipolar transistors (IGBTs), and thermal stress has a significant impact on IGBT failure. The randomness and volatility of wind energy cause the input power of wind power converters to fluctuate greatly, resulting in drastic changes in the thermal stress of IGBTs. In addition, the difference in thermal expansion coefficients between different material layers can also easily lead to the occurrence of open circuit (OC) faults. OC faults of IGBTs are the main type of faults in wind power converters. Generally speaking, due to the rapid evolution of short circuit (SC) faults in power devices, SC faults can be converted into OC faults by adding fast fuses to the converter bridge arms.

[0005] OC faults generally do not cause the converter to shut down immediately, but they will cause the three-phase current / voltage to deteriorate and the neutral point voltage to be unbalanced, further leading to secondary faults in other healthy devices and even causing the entire converter to shut down. In traditional control strategies, when an OC fault occurs in a single converter in a parallel converter system, the faulty converter will be completely cut off and the system will operate at a lower power level. If all converters fail, the wind turbine will shut down as a protective measure. Therefore, fault-tolerant control technology is essential to ensure the stable operation of wind turbines when components fail.

[0006] Fault-tolerant control is usually divided into two types: redundant and non-redundant. The redundant method is usually implemented by adding redundant bridge arms or virtual bridge arms. After isolating the faulty bridge arm, the redundant bridge arm is put into use to replace the faulty bridge arm, thereby realizing the reconfiguration of the converter after the fault. The virtual bridge arm uses a bidirectional switch tube to connect the faulty bridge arm to the midpoint of the DC bus. The converter uses the virtual bridge arm of the DC bus to operate in a three-phase four-bridge arm mode, thereby realizing the reconfiguration of the bridge arm current after the fault. When using redundant bridge arms and virtual bridge arms to reconfigure the converter, each phase bridge arm needs to be configured with a bidirectional switch tube. The non-redundant method is implemented at the software level without the need to invest in additional hardware, and is the first choice for large-capacity power converter applications. The general method is that the entire converter shares a bridge arm, and the converter operates in a five-bridge arm mode. The shared bridge arm needs to be configured with an auxiliary bidirectional switch tube, which is essentially a hardware-assisted, software-optimized control method. Non-redundant fault-tolerant control can also be achieved by modifying the SVPWM algorithm, which is essentially to modify the compensation ratio of the voltage vector. This method maximizes the fault tolerance performance of a single converter. It only modifies the control strategy, so it is not the best choice for parallel converter systems. Fault-tolerant control of parallel converter systems is generally achieved by current reconstruction. After a fault occurs, the phase current reference value of each converter in the converter system is reconfigured according to the health status of the bridge arm.

[0007] Most of the above methods are for a single converter, which is not the best choice for a parallel converter system. The above methods for a parallel converter system require the removal of the entire faulty bridge arm, which cannot fully utilize the remaining healthy switch tubes. Therefore, it is necessary to study a new non-redundant fault-tolerant control strategy for parallel converter systems with lower economic costs and more balanced switch tube life. Summary of the invention

[0008] In order to solve the above problems, the present invention proposes a non-redundant fault-tolerant control method and system for a parallel wind power conversion system. The present invention does not require additional redundant hardware, and only needs to modify the phase current reference instruction of each converter in the parallel conversion system according to the current direction of the power grid. There is no need to disconnect the faulty bridge arm, and only needs to isolate the faulty switch tube, so that the remaining healthy switch tubes can be fully utilized, thereby making the life of all switch tubes in the conversion system more balanced, and improving the reliability of the offshore wind power conversion system.

[0009] According to some embodiments, the present invention adopts the following technical solutions:

[0010] A non-redundant fault-tolerant control method for a parallel wind power conversion system comprises the following steps:

[0011] Determine whether there is a switch failure. If yes, determine the fault type. Otherwise, determine the switch control instruction through the model prediction control strategy.

[0012] If the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty, the switch control command is determined by the model predictive control strategy; otherwise:

[0013] Determine the state health function of each switch tube;

[0014] Reconstruct the reference current according to the health function of each switch and the direction of grid current;

[0015] Based on the reconstructed reference current, current hysteresis control is performed to obtain a switch control instruction for each switch tube.

[0016] As an optional implementation, the specific process of determining the state health function of each switch tube includes: defining H xy is the health status function of the yth switch tube on phase x:

[0017]

[0018] Among them, G xy It is the yth switch tube of phase x.

[0019] As an optional implementation, the specific process of reconstructing the reference current according to the state health function of each switch tube and the flow direction of the grid phase current includes:

[0020] A reference phase current reconstruction table is constructed, and the corresponding reference current is reconstructed according to the reference phase current flow direction and the health status function of each switch tube. The reference phase current reconstruction table is:

[0021]

[0022]

[0023] Among them, i x is the phase current of phase x of the power grid, are the x-phase reference current of a single converter in the converter system, H xy It is the health status function of the yth switch tube on the x phase, and y is an integer.

[0024] As an optional implementation, the specific process of performing the current hysteresis control includes: when the current reaches a boundary condition, changing the switching state of the converter to ensure that the current is within the hysteresis loop.

[0025] As a further step, the current error is used as the input of the comparator. If the phase current error is higher than the upper limit value, the upper tube of the corresponding phase bridge arm is turned off and the lower tube is turned on; if the phase current error is lower than the upper limit value, the upper tube of the corresponding phase bridge arm is turned on and the lower tube is turned off.

[0026] As an optional implementation, the specific process of determining the switch control instruction through the model predictive control strategy includes: establishing a cost function, discretizing the converter phase current formula under the sampling time, replacing the row phase current derivative with forward Euler approximation, and bringing it into the continuous model of the converter system to obtain the current value.

[0027] As an alternative embodiment, the method is used on the generator side and / or the grid side.

[0028] A non-redundant fault-tolerant control system for a parallel wind power conversion system, comprising:

[0029] A fault judgment module is configured to judge whether there is a switch tube fault, and if so, determine the fault type, otherwise determine the switch control instruction through a model prediction control strategy;

[0030] The type judgment module is configured to determine the switch control instruction by the model prediction control strategy if the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty; otherwise:

[0031] A state health function determination module is configured to determine the state health function of each switch tube;

[0032] A reference current reconstruction module is configured to reconstruct the reference current according to the state health function of each switch tube and the current flow direction of the power grid;

[0033] The current hysteresis control module is configured to perform current hysteresis control based on the reconstructed reference current to obtain a switch control instruction for each switch tube.

[0034] An electronic device comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor. When the computer instructions are executed by the processor, the steps in the above method are completed.

[0035] A parallel wind power conversion system comprises the above-mentioned non-redundant fault-tolerant control system, or uses the above-mentioned method to control parallel converters.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention reconfigures the three-phase current reference instructions of each converter in the converter system according to the health status of the converter system. This method makes full use of all healthy switch tubes, makes the equipment life more balanced, and further improves the reliability and availability of the system. The simulation results also verify the effectiveness and feasibility of the proposed control strategy, which can achieve continuous operation of wind turbines when operation and maintenance cannot be timely.

[0038] The present invention is based on the software level and does not require redundant hardware, thereby reducing economic costs.

[0039] Compared with the traditional method, the present invention does not need to add redundant devices, and does not need to cut off the entire faulty bridge arm. It only needs to isolate the faulty switch tube, thereby improving the utilization rate of the remaining healthy switch tubes, making the life of all switch tubes in the converter system more balanced, thereby promoting the improvement of the service life of the converter system.

[0040] The present invention is applicable to single-tube fault, double-tube fault and multi-phase fault of the converter system. Since there is no need to modify the control strategy, it is not restricted by the converter topology; only the phase current reference instruction needs to be modified, and the converter control algorithm does not need to be modified.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0043] Figure 1 This is a schematic diagram of a two-level wind power parallel conversion system of this embodiment;

[0044] Figure 2 This is a schematic diagram of the current path of the two-level wind power parallel conversion system of this embodiment;

[0045] Figure 3 This is a non-redundant fault-tolerant control block diagram of this embodiment;

[0046] Figure 4 This is a non-redundant fault-tolerant control flow chart of this embodiment. DETAILED DESCRIPTION

[0047] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0048] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] In the absence of conflict, the embodiments in this application and the features in the embodiments may be combined with each other.

[0051] Embodiment 1

[0052] This embodiment uses Figure 1 The two-level wind power parallel converter system shown is used to illustrate the application scenario, but it does not mean that the technical solution provided by the present invention can only be used in this scenario. In theory, any parallel converter system can use the solution provided by the present invention.

[0053] A non-redundant fault-tolerant control method for parallel wind power conversion system faults modifies the phase current reference instruction of each converter in the conversion system according to the health status of each IGBT in the conversion system to achieve continuous operation of wind turbines when maintenance is not timely. All healthy switch tubes are fully utilized to make the equipment life more balanced, further improving the reliability and availability of the system.

[0054] like Figure 4 As shown, a non-redundant fault-tolerant control method for a parallel wind power conversion system fault includes the following steps:

[0055] Determine whether there is a switch failure. If yes, determine the fault type. Otherwise, determine the switch control instruction through the model prediction control strategy.

[0056] If the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty, the switch control command is determined by the model predictive control strategy; otherwise:

[0057] Determine the state health function of each switch tube;

[0058] Reconstruct the reference current according to the health function of each switch and the direction of grid current;

[0059] Based on the reconstructed reference current, current hysteresis control is performed to obtain a switch control instruction for each switch tube.

[0060] The specific details are described below.

[0061] The topological structure of the two-level parallel wind power conversion system (taking the grid-side converter as an example) is as follows: Figure 1 shown.

[0062] The two-level parallel wind power conversion system includes a three-phase voltage source (e a ,e b ,e c ), three with equivalent resistance R g The grid-side filter inductor L g , 12 IGBTG xy (x∈{a,b,c},y∈{1,2,3,4}, the same below) and 12 anti-parallel freewheeling diodes D xy , and DC link capacitors C1 and C2 (assuming C1 = C2). Figure 1 In, V dc1 and V dc2 represents the capacitor voltage, i xm and u xm (m∈{1,2}, the same below) represents the output phase current and voltage.

[0063] The switch state of the two-level parallel wind power conversion system can be defined by the gate signal:

[0064]

[0065] The output voltage of phase x can be described as

[0066] u xm =V dcm ·S xy (2)

[0067] like Figure 1 As shown, applying Kirchhoff's voltage law, the continuous model of the two-level parallel wind power conversion system can be obtained as follows:

[0068]

[0069] for Figure 1 The phase voltage between point N and point O.

[0070] Between different phases, faults will not couple with each other. Therefore, the fault-tolerant control method for multi-phase faults is to add the phase current reconstruction instructions for single-phase faults.

[0071] The single-phase faults of the parallel converter system are divided into single-tube fault, double-tube fault, triple-tube fault and quad-tube fault, which are defined as F k-i ,F k-ij ,F k-ijt ,F k4 , where k represents the phase of the faulty switch, k∈{a,b,c} and i,j,t represent the positions of the faulty switch. a-1 Represents Ga1 Fault; F a-14 Represents G a1 and G a4 Fault; F a-124 Represents G a1 ,G a2 and G a4 Fault; F a4 It indicates that all the switching tubes of phase A are faulty.

[0072] It should be noted that if more than two switches fail in the same phase, the reference current cannot be reconfigured because the positive or negative current flowing through the phase in the parallel converter system will be blocked.

[0073] In this embodiment, when reconstructing the reference current, it is necessary to reconstruct the reference current of each phase in all converters in combination with the health status function of the switch tube.

[0074] The health status function of the switch tube is:

[0075]

[0076] When a switch fails, the reference current command is rebuilt according to the grid current flow direction. The current path of the parallel conversion system is as follows: Figure 2 As shown in Figure 2, we can infer the impact of switch failure on each converter phase current. x When G is greater than 0, x2 and G x4 When it fails, the current path will be blocked. x1 and G x3 The health status of i has no effect on the normal operation of the conversion system; x When it is less than 0, only when G x1 and G x3 In the event of a failure, the current path will be blocked. x2 and G x4 The health status of the system has no impact on the normal operation of the system.

[0077] After the above derivation, the reference current of each converter can be calculated according to the health status of all switches in each phase. In the stationary coordinate system, the phase current of each converter is independently controlled. Therefore, the reference current of each phase can be given (k = a, b, c), as shown in Table 1.

[0078] Table 1 Reference phase current reconstruction table

[0079]

[0080] i x is the phase current of phase x of the power grid, They are Figure 1 The x-phase reference phase current of converter 1 and converter 2.

[0081] Usually, G x2 and G x4 Shared positive phase current, G x1 and G x3 Shared negative phase current. When a switch fails, there is no need to remove the entire line where the failed switch is located, but only to reconfigure the reference phase current of each converter. This method can make better use of each switch and make its life more balanced, which is beneficial to the maintenance of the entire conversion system.

[0082] When executing the non-redundant fault-tolerant control method of the parallel wind power conversion system, such as Figure 3 As shown, when the converter is operating normally, the switch control instructions during normal operation are obtained through the model predictive control (MPC) strategy.

[0083] The proportional-integral (PI) regulator of the voltage outer loop outputs the d-axis reference current and selects the corresponding operating mode according to the health status function of each leg of the converter, thereby obtaining the current reference command of each leg of each converter in the three-phase stationary coordinate system. It can be used to predict the future system state. It is used to predict the future system state. The expected control results are then wisely integrated to establish a cost function for evaluation, and a finite number of control sequences corresponding to a finite number of future states are evaluated to obtain the optimal future control sequence that minimizes the pre-established cost function. There are two main types of reference signals commonly used in MPC solutions, one is tracking the current reference signal (i.e., model predictive current control, MPCC), and the other is tracking the power reference signal (i.e., model predictive power control, MPPC).

[0084] The purpose of this embodiment is to make the actual phase current of each converter consistent with the reference phase current, so MPCC is used.

[0085] First, establish the cost function:

[0086]

[0087] In the formula, i d (k+1) and i q (k+1) refers to the real and imaginary parts of the predicted converter phase current vector i(k+1); and is the reference current vector i * The real and imaginary parts of (k+1).

[0088] For the sampling time T sThe following converter phase current formula is discretized, and the row phase current derivative di / dt is replaced by the forward Euler approximation, that is, the derivative is approximated by the following formula:

[0089]

[0090] Substituting equation (3) with equation (6), we get the following expression:

[0091]

[0092] This expression allows predicting the current value at time k+1 for each of the seven voltage vectors generated by the converter.

[0093] When a switch fails, the seven voltage vectors generated by the converter will be distorted, and the MPPC control strategy will no longer be applicable. Therefore, this embodiment adopts a hysteresis current control strategy during fault-tolerant operation to quickly track the reference current. The basic idea of ​​hysteresis current control is that whenever the current reaches the boundary condition, the switching state of the converter can be changed to ensure that the current is inside the hysteresis loop. Here, the current error is used as the input of the comparator. If the phase current error is higher than the upper limit value, the upper tube of the phase bridge arm is turned off and the lower tube is turned on; if the phase current error is lower than the upper limit value, the upper tube of the phase bridge arm is turned on and the lower tube is turned off; the loop width controller has good performance and fast dynamic response.

[0094] In order to avoid harmful effects caused by magnetic circuit coupling of three-phase inductors under asymmetric working conditions and improve the reliability of filter inductors and the fault tolerance performance of high-power wind power conversion systems, this embodiment uses the three-phase filter inductors as three single-phase inductors.

[0095] In some embodiments, although the control structures of the generator-side and grid-side conversion systems are different, the fault-tolerant control is similar. They are both reference instructions for reconfiguring the current inner loop. Therefore, the non-redundant fault-tolerant control strategy of the generator-side conversion system can be obtained by the same principle.

[0096] Embodiment 2

[0097] A non-redundant fault-tolerant control system for a parallel wind power conversion system, comprising:

[0098] A fault judgment module is configured to judge whether a switch tube fails, and if so, determine the fault type, otherwise determine the switch control instruction through a model prediction control strategy;

[0099] The type judgment module is configured to determine the switch control instruction by the model prediction control strategy if the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty; otherwise:

[0100] A state health function determination module is configured to determine the state health function of each switch tube;

[0101] A reference current reconstruction module is configured to reconstruct the reference current according to the state health function of each switch tube and the current flow direction of the power grid;

[0102] The current hysteresis control module is configured to perform current hysteresis control based on the reconstructed reference current to obtain a switch control instruction for each switch tube.

[0103] Embodiment 3

[0104] A parallel wind power conversion system includes the non-redundant fault-tolerant control system described in the second embodiment, or the method of the first embodiment is applied to control the parallel converters.

[0105] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0106] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0108] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention without creative labor shall be included in the protection scope of the present invention.

Claims

1. A non-redundant fault-tolerant control method for a parallel wind power conversion system, characterized in that: The following steps are involved: Determine whether there is a switch failure. If yes, determine the fault type. Otherwise, determine the switch control instruction through the model prediction control strategy. If the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty, the switch control command is determined by the model predictive control strategy; otherwise: Determine the state health function of each switch tube; Reconstruct the reference current according to the health function of each switch and the direction of grid current; Based on the reconstructed reference current, current hysteresis control is performed to obtain a switch control instruction for each switch tube; According to the health function of each switch tube and the current flow direction of the grid, the specific process of reconstructing the reference current includes: A reference phase current reconstruction table is constructed, and the corresponding reference current is reconstructed according to the reference phase current flow direction and the health status function of each switch tube. The reference phase current reconstruction table is: Among them, i x is the phase current of phase x of the power grid, are the x-phase reference currents of different converters, H xy is the health status function of the yth switch tube on the x phase, y is an integer; The specific process of determining the state health function of each switch tube includes: xy is the health status function of the yth switch tube on phase x: Among them, G xy It is the yth switch tube of phase x.

2. A non-redundant fault-tolerant control method for a parallel wind power conversion system according to claim 1, characterized in that: The specific process of performing current hysteresis control includes: when the current reaches the boundary condition, changing the switching state of the converter to ensure that the current is within the hysteresis loop.

3. A non-redundant fault-tolerant control method for a parallel wind power conversion system according to claim 2, characterized in that: The current error is used as the input of the comparator. If the phase current error is higher than the upper limit value, the upper tube of the corresponding phase bridge arm is turned off and the lower tube is turned on; if the phase current error is lower than the upper limit value, the upper tube of the corresponding phase bridge arm is turned on and the lower tube is turned off.

4. The non-redundant fault-tolerant control method for a parallel wind power conversion system according to claim 1, characterized in that: The specific process of determining the switch control command through the model predictive control strategy includes: establishing a cost function, discretizing the converter phase current formula under the sampling time, replacing the row phase current derivative with the forward Euler approximation, and bringing it into the continuous model of the converter system to obtain the current value.

5. The non-redundant fault-tolerant control method for a parallel wind power conversion system according to claim 1, characterized in that: The method is used on the generator side and / or the grid side.

6. A non-redundant fault-tolerant control system for a parallel wind power conversion system, based on a non-redundant fault-tolerant control method for a parallel wind power conversion system as claimed in any one of claims 1 to 5, characterized in that: include: A fault judgment module is configured to judge whether a switch tube fails, and if so, determine the fault type, otherwise determine the switch control instruction through a model prediction control strategy; A type judgment module is configured to determine a switch control instruction through a model predictive control strategy if the fault type is that all upper tubes of the same phase of all converters in the wind power conversion system are faulty or all lower tubes of the same phase are faulty; otherwise: A state health function determination module is configured to determine the state health function of each switch tube; A reference current reconstruction module is configured to reconstruct the reference current according to the state health function of each switch tube and the current flow direction of the power grid; The current hysteresis control module is configured to perform current hysteresis control based on the reconstructed reference current to obtain a switch control instruction for each switch tube.

7. An electronic device, characterized in that: The method comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the steps in the method according to any one of claims 1 to 5 are completed.

8. A parallel wind power conversion system, characterized in that: The method comprises the non-redundant fault-tolerant control system as claimed in claim 6, or controls the parallel converters by applying the method as claimed in any one of claims 1 to 5.

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