Converter protection control method and device based on steady-state current prediction and storage medium

Abstract

This invention discloses a converter protection control method, device, and storage medium based on steady-state current prediction. The method includes the following steps: real-time acquisition of the output voltage / current of the controlled converter; inputting the control parameter information of the PWM controller in the controlled converter and the real-time acquired output voltage / current of the controlled converter into the load impedance calculation model, and determining whether the change value of the load impedance of the controlled converter exceeds a preset threshold; if the change value of the load impedance of the controlled converter exceeds the preset threshold, updating the steady-state model of the converter arm current using the current load impedance value to perform steady-state current prediction, and obtaining the predicted steady-state current value of the converter arm; and performing protection control based on the predicted steady-state current value of the converter arm. This invention has the advantages of simple implementation, high efficiency and accuracy of control and protection, fast response speed, and the ability to predict protection in advance.

Description

Technical Field

[0001] This invention relates to the field of converter control technology, and in particular to a converter protection control method, device and storage medium based on steady-state current prediction. Background Technology

[0002] Converter protection and control is a crucial aspect affecting the safety and reliability of converter products. Traditional converter protection and control typically employs methods such as digital signal protection and analog signal protection. Digital signal protection determines whether a fault is detected by comparing the captured digital fault signal with a target fault value; if they match, a fault is identified, the converter is shut down, and the fault is locked. Analog signal protection typically uses sensors to detect the converter's voltage and current, comparing the detected voltage and current with threshold values ​​to determine whether protection should be initiated, or it determines protection based on the trend of voltage and current changes.

[0003] In converter protection and control, especially overvoltage and overcurrent protection, if protection is not timely when a fault occurs, significant voltage and current stresses can form on the converter, affecting its safety and reliability. The traditional protection and control methods mentioned above are based on the absolute values ​​or trends of voltage and current signals. These methods are passive fault protection, meaning they only trigger protection accurately when the voltage and current rise to near the protection threshold. Therefore, protection control can only be initiated after a fault occurs, failing to predict and prevent fault occurrence in advance. Consequently, significant voltage and current stresses still form on the converter when a fault occurs, impacting its safety and reliability. Summary of the Invention

[0004] The technical problem to be solved by this invention is: in view of the technical problems existing in the prior art, this invention provides a converter protection control method, device and storage medium based on steady-state current prediction that is simple to implement, has high efficiency and accuracy in control and protection, and fast response speed, and can accurately judge the impending fault and carry out protection control in the early stage of the fault.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0006] A converter protection and control method based on steady-state current prediction includes the following steps:

[0007] Real-time acquisition of the output voltage / current of the controlled converter;

[0008] The control parameter information of the PWM controller in the controlled converter and the output voltage of the controlled converter acquired in real time are input into the load impedance calculation model to determine whether the change value of the load impedance of the controlled converter exceeds a preset threshold. The load impedance calculation model is a relationship model between the load impedance in the converter and the output voltage / current and the control parameter information of the PWM controller.

[0009] If it is determined that the change in the load impedance of the controlled converter exceeds the preset change threshold, the current load impedance value is used to update the steady-state model of the converter arm current to predict the steady-state current and obtain the predicted steady-state current value of the converter arm. The steady-state model of the converter arm current is a model of the relationship between the steady-state current value of the arm and the load impedance in the converter.

[0010] Control commands are sent based on the predicted steady-state current value of the converter bridge arm to perform protection control on the controlled converter.

[0011] Furthermore, based on the system transfer function of the controlled converter system, the relationship expression between the load impedance in the converter and the output voltage / current of the converter, the inner loop transfer function of the PWM controller, and the outer loop PI transfer function of the PWM controller is constructed to obtain the load impedance calculation model. The controlled converter system includes the controlled converter and the PWM controller.

[0012] Furthermore, the expression for the load impedance calculation model is as follows:

[0013]

[0014]

[0015]

[0016] Among them, R load For the load impedance, u Cd For the active component of the output voltage / current, u Cd_ref G serves as a reference value for the active component of the output voltage / current. u G is the outer loop transfer function of the PWM controller. in Let i be the inner loop transfer function of the PWM controller. L i is the converter bridge arm current. Ld_ref k is the reference value for the converter bridge arm current. ip k is the proportional gain of the PI controller in the inner loop. ii K represents the integral coefficient of the PI controller in the inner loop, L is the output filter inductance value in the converter, and k is the integral coefficient of the PI controller in the inner loop. up k is the proportional gain of the PI controller in the outer loop. uiC is the integral coefficient of the PI controller in the outer loop, and C is the capacitance of the output filter capacitor in the converter.

[0017] Furthermore, the output filter capacitor current in the converter arm current calculation model is approximated as 0 to represent the short-circuit condition of the tested converter system, thus obtaining the steady-state model of the converter arm current.

[0018] Furthermore, the expression for the steady-state model of the converter arm current is:

[0019]

[0020] Among them, i' L For the steady-state current of the converter bridge arm, u C R represents the output voltage / current of the converter. load This represents the load impedance in the converter.

[0021] Furthermore, the protection control of the controlled converter based on the predicted steady-state current value of the converter bridge arm includes: if the predicted steady-state current value of the converter bridge arm is greater than a preset steady-state current threshold, then the pulse of the PWM controller is blocked.

[0022] Furthermore, if it is determined that the change in the load impedance of the controlled converter is less than the preset change threshold, the output voltage / current of the controlled converter will continue to be monitored in real time to determine the change in the load impedance of the controlled converter.

[0023] A converter protection and control device based on steady-state current prediction includes:

[0024] The real-time acquisition module is used to acquire the output voltage / current of the controlled converter in real time.

[0025] The load impedance change judgment module is used to input the control parameter information of the PWM controller in the controlled converter and the output voltage / current of the controlled converter in real time into the load impedance calculation model to determine whether the change value of the load impedance of the controlled converter exceeds a preset threshold. The load impedance calculation model is a relationship model between the load impedance in the converter and the output voltage / current and the control parameter information of the PWM controller.

[0026] The steady-state current prediction module is used to update the steady-state model of the converter arm current to predict the steady-state current if the load impedance change judgment module determines that the change value of the load impedance of the controlled converter exceeds a preset change threshold. The predicted steady-state current value of the converter arm is obtained. The steady-state model of the converter arm current is a model of the relationship between the steady-state current value of the arm in the converter and the load impedance.

[0027] The control output module is used to send control commands based on the predicted steady-state current value of the converter bridge arm to perform protection control on the controlled converter.

[0028] An electronic device includes a processor and a memory, the memory being used to store a computer program, and the processor being used to execute the computer program to perform the method described above.

[0029] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described above.

[0030] Compared with the prior art, the advantages of the present invention are as follows: The present invention obtains the output voltage / current of the controlled converter in real time, calculates the load impedance value based on the load impedance calculation model, and judges the change state. When the load impedance changes, the steady-state model of the converter arm current is updated using the real-time load impedance, and the steady-state current value of the converter arm under the condition of load impedance change is predicted. Then, control and protection are performed based on the predicted steady-state current value of the converter arm. It can realize the prediction of the voltage and current state of the converter system, so that the impending fault can be accurately judged in the early stage of the fault, before the voltage and current rise to exceed the normal range, and control and protection can be performed in advance, without having to wait for the current to rise to close to the protection value. This can significantly reduce the voltage and current stress on the converter under overvoltage and overcurrent faults, and ensure the safe and reliable operation of the converter. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structural principle of a three-phase inverter circuit in a specific application embodiment.

[0032] Figure 2 This is a schematic diagram of the structure and principle of the converter and control topology in a specific application embodiment.

[0033] Figure 3 This is a schematic diagram illustrating the implementation process of the converter protection and control method based on steady-state current prediction in this embodiment.

[0034] Figure 4 This is a schematic diagram illustrating the implementation principle of the converter protection and control method based on steady-state current prediction in a specific application embodiment of the present invention.

[0035] Figure 5 This is a schematic diagram of the system control structure of the converter system in a specific application embodiment of the present invention.

[0036] Figure 6 This is a schematic diagram of the inner loop control structure in the PWM controller of the present invention in a specific application embodiment.

[0037] Figure 7This is a detailed flowchart illustrating the implementation of converter protection control in a specific application embodiment of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0039] by Figure 1 Taking the three-phase inverter circuit shown as an example, it includes three converter bridge arms. A filter circuit is installed at the output terminal of the converter, including an output filter inductor L and an output filter capacitor C. The output filter capacitor C is connected in a delta configuration. The output terminal of the auxiliary converter is controlled to turn on and off via an output contactor KMA. The converter is controlled by a control unit, such as... Figure 2 As shown, this control unit can specifically employ a high-performance digital controller to accurately acquire the output voltage / current of the auxiliary inverter and control it in conjunction with the DC voltage and output current. The control unit specifically includes digital input / output (DIO), analog input (APA), pulse conversion, logic control (SMC), signal processing (LSC), and digital arithmetic (ACC), etc.

[0040] During normal operation of the converter, the voltage and current waveforms of each component can be calculated in real time using circuit equations. For example, given the output voltage, the inductor current satisfies:

[0041]

[0042] Where L is the output filter inductance value, R is the load impedance, and I... f U is the inductor current. in U is the input voltage. c This is the output voltage.

[0043] The inductor current value can be obtained by solving the above equation.

[0044] The steady-state circuit equations of the system can be used to calculate the current state of the system when it reaches steady state. For example, the inductor current value in steady state satisfies:

[0045] RI f =U in -U c (2)

[0046] As shown in equation (2), the inductor current value under steady-state conditions can be calculated once the output voltage and load impedance are determined. If the real-time load impedance changes, the calculation model for the inductor current value under steady-state conditions will change. Therefore, the inductor current value under future steady-state conditions can be predicted based on the real-time changing load impedance. The load impedance will change in the early stage of a fault. Therefore, by judging the change state of the load impedance in real time, and combining the real-time load impedance with the current calculation model under steady-state conditions, the future inductor current value can be predicted. This allows for timely prediction of the fault in the early stage of a fault, and timely and effective control and protection before the actual current rises, effectively reducing the impact of the fault on the converter.

[0047] This invention first constructs a load impedance calculation model for calculating real-time load impedance and a converter arm current steady-state model for predicting the steady-state current of the converter arm. After acquiring the output voltage / current of the controlled converter in real time, the load impedance value is calculated based on the load impedance calculation model to determine the change state. When the load impedance changes, the converter arm current steady-state model is updated using the real-time load impedance to predict the steady-state current value of the converter arm under the condition of load impedance change. Then, control and protection are performed based on the predicted steady-state current value of the converter arm. This can realize the prediction of the voltage and current state of the converter system, so that the impending fault can be accurately judged in the early stage of the fault, before the voltage and current rise above the normal range, and control and protection can be performed in advance, without waiting for the current to rise to close to the protection value. This can significantly reduce the voltage and current stress on the converter under overvoltage and overcurrent faults and ensure the safe and reliable operation of the converter.

[0048] like Figure 3 , 4 As shown, the steps of the converter protection and control method based on steady-state current prediction in this embodiment include:

[0049] Step S01. Obtain the output voltage / current of the controlled converter in real time.

[0050] In this embodiment, the output voltage / current of the converter is monitored in real time by an output voltage / current sensor at the output terminal of the converter, and the monitoring results uploaded by the output voltage / current sensor are received to obtain the output voltage / current of the controlled converter in real time.

[0051] Understandably, the output voltage / current of the controlled converter can also be monitored in real time using an additional monitoring unit, which can be configured according to actual needs.

[0052] Step S02. Input the control parameter information of the PWM controller in the controlled converter and the output voltage / current of the controlled converter obtained in real time into the load impedance calculation model, and determine whether the change value of the load impedance of the controlled converter exceeds the preset threshold. The load impedance calculation model is a relationship model between the load impedance in the converter and the output voltage / current and the control parameter information of the PWM controller.

[0053] The load impedance can be calculated from the control parameters of the inner and outer loops of the PWM controller and the output voltage / current of the converter. In this embodiment, the relationship between the load impedance of the converter and the output voltage / current of the converter, the inner loop transfer function of the PWM controller, and the outer loop PI transfer function of the PWM controller are constructed based on the system transfer function of the controlled converter system. This yields the load impedance calculation model. The controlled converter system includes the controlled converter and the PWM controller.

[0054] In this embodiment, the converter system and the inner loop control structure are respectively as follows: Figure 5 , Figure 6 As shown, the inner loop transfer function is:

[0055]

[0056] Among them, G in Let i be the inner loop transfer function of the PWM controller. L i is the converter bridge arm current. Ld_ref k is the reference value for the converter bridge arm current. ip k is the proportional gain of the PI controller in the inner loop. ii is the integral coefficient of the PI controller in the inner loop.

[0057] The outer loop transfer function is:

[0058]

[0059] Among them, G u For the outer loop transfer function of the PWM controller, k up k is the proportional gain of the PI controller in the outer loop. ui is the integral coefficient of the PI controller in the outer loop.

[0060] The expression for calculating the output current is:

[0061]

[0062] Among them, R load For the load impedance, u Cd This represents the active component of the output voltage.

[0063] This allows us to obtain the system transfer function of the converter system:

[0064]

[0065] Among them, u Cd_ref C is the reference value for the active component of the output voltage, and C is the capacitance value of the output filter capacitor in the converter.

[0066] The expression for the load impedance calculation model used to calculate the load impedance is then obtained as follows:

[0067]

[0068] Once the voltage and current values ​​of the converter are obtained in real time, the load impedance value can be calculated in real time according to the above formula (7), and then it can be determined whether the load impedance value has changed. If the load impedance value changes, it means that a fault such as a short circuit may occur. Then, the steady-state model of the converter arm current can be updated according to the load impedance value to predict the steady-state current value of the converter arm.

[0069] Step S03. If it is determined that the change in the load impedance of the controlled converter exceeds the preset change threshold, the current load impedance value is used to update the steady-state model of the converter arm current to predict the steady-state current and obtain the predicted steady-state current value of the converter arm. The steady-state model of the converter arm current is a model of the relationship between the steady-state current value of the arm and the load impedance in the converter.

[0070] In this embodiment, the converter arm current calculation model is constructed as shown below:

[0071]

[0072] When a short circuit occurs in the system, the output current will be much greater than the capacitor current. Therefore, the current of the output filter capacitor in the above converter arm current calculation model is approximated as 0 to represent the short-circuit condition of the tested converter system. This yields the steady-state model of the converter arm current, expressed as:

[0073]

[0074] Among them, i' L For the steady-state current of the converter bridge arm, u C R is the output voltage of the converter. load This represents the load impedance in the converter.

[0075] When the real-time load impedance is calculated based on the real-time voltage and current of the converter, and it is determined that the real-time load impedance changes, the model is updated by substituting it into the steady-state model of the converter arm current in the above equation (9). In this way, the future steady-state voltage and current of the current system can be predicted based on the steady-state model with new parameters, and the control protection can be started in time based on the predicted future steady-state voltage and current state.

[0076] In this embodiment, if it is determined that the change in the load impedance of the controlled converter is less than the preset change threshold, the process returns to step S01 to continue monitoring the output voltage / current of the controlled converter in real time in order to determine the change in the load impedance of the controlled converter.

[0077] Step S04. Send control commands to protect the controlled converter based on the predicted steady-state current value of the converter bridge arm.

[0078] In this embodiment, the protection control of the controlled converter based on the predicted steady-state current value of the converter arm includes: if the predicted steady-state current value of the converter arm is greater than the preset steady-state current threshold, the pulse of the PWM controller is blocked, and the pulse blocking shutdown is performed to realize the protection judgment of the predicted future steady-state voltage and current.

[0079] In specific application embodiments, such as Figure 7 As shown, firstly, the output voltage and current information of the converter are collected in real time. When the converter experiences a load short circuit or other fault, the control software quickly combines the controller's control information (inner and outer loop control parameters, etc.) to perform real-time model calculation on the transient real-time circuit model (such as the load impedance calculation model in equation (7)) to realize the real-time load impedance R of the converter. load The calculation; the new load impedance R is obtained through calculation. load The value determines the change in the model; if there is no change, real-time monitoring continues. If the new load impedance R... load When the value changes (greater than the preset change threshold), it is substituted into the predicted stable circuit equation (such as the steady-state model of the converter bridge arm current in equation (9)) to update the steady-state model. The predicted voltage and current are a result under the new model, that is, the predicted steady-state voltage and current values. Then, the predicted voltage and current values ​​are used for protection judgment. It can be quickly determined that the current will exceed the set protection threshold after the system reaches a steady state in the future. Before the actual current rises, the pulse is quickly blocked and the predicted protection shutdown is performed, thereby realizing the prediction protection of converter voltage and current. Since the protection action can be performed immediately after the model calculation is completed, the pulse is blocked and the shutdown is performed when the predicted voltage and current exceed the protection value. Otherwise, real-time monitoring continues. It is not necessary to wait for the current to rise to close to the protection value. Therefore, the fault that is about to occur can be judged in a timely and accurate manner in the early stage of the fault, and the shutdown can be performed in advance. The above change threshold and protection threshold can be set according to actual needs.

[0080] Using the method described above, it is possible to predict in advance that the converter will be protected when a fault occurs but before the voltage and current have risen, thereby reducing the voltage and electrical stress at the time of the fault. Moreover, it does not require additional hardware detection or modification of control information and can operate independently. It is not only simple and easy to implement, but also has high real-time performance and strong flexibility, making it very suitable for digital signal control.

[0081] This embodiment of the converter protection and control device based on steady-state current prediction includes:

[0082] The real-time acquisition module is used to acquire the output voltage / current of the controlled converter in real time.

[0083] The load impedance change judgment module is used to input the control parameter information of the PWM controller in the controlled converter and the output voltage / current of the controlled converter in real time into the load impedance calculation model to determine whether the change value of the load impedance of the controlled converter exceeds the preset threshold. The load impedance calculation model is a relationship model between the load impedance in the converter and the output voltage / current and the control parameter information of the PWM controller.

[0084] The steady-state current prediction module is used to update the steady-state model of the converter arm current to predict the steady-state current if the load impedance change judgment module determines that the change value of the load impedance of the controlled converter exceeds the preset change threshold. The predicted steady-state current value of the converter arm is obtained. The steady-state model of the converter arm current is a model of the relationship between the steady-state current value of the arm in the converter and the load impedance.

[0085] The control output module is used to send control commands based on the predicted steady-state current value of the converter bridge arm to protect and control the controlled converter.

[0086] like Figure 4 As shown, the real-time acquisition module is used to acquire the output voltage / current of the controlled converter in real time. The input terminal of the real-time acquisition module is connected to the output terminal of the controlled converter, and the output terminal of the real-time acquisition module is connected to the load impedance change judgment module. The load impedance change judgment module calculates the real-time load impedance. The output terminal of the load impedance change judgment module is connected to the input terminal of the steady-state current prediction module. When the load impedance change judgment module detects a change in load impedance, the steady-state current prediction module updates the steady-state model and predicts the steady-state current value of the converter arm. The output terminal of the steady-state current prediction module is connected to the input terminal of the control output module. The control output module performs protection judgment and determines whether the predicted steady-state current value of the converter arm is greater than the preset protection threshold. If it is greater than the preset protection threshold, the control module sends a control command to the PWM controller to block the pulse, thereby realizing the control and protection of the controlled converter.

[0087] In this embodiment, the load impedance change judgment module specifically includes a real-time model calculation unit and a change judgment unit. The real-time model calculation unit is used to input the control parameter information of the PWM controller in the controlled converter and the output voltage / current of the controlled converter obtained in real time into the load impedance calculation model to calculate the real-time load impedance and output it to the change judgment unit. The change judgment unit is used to compare the received real-time load impedance with the historical load impedance and determine whether the change value of the load impedance exceeds a preset threshold. If it exceeds the preset change threshold, it will switch to the steady-state current prediction module.

[0088] In this embodiment, the steady-state current prediction module specifically includes a startup control module and a model update unit. The startup control module is used to control the startup of the model update unit if the load impedance change judgment module determines that the change value of the load impedance of the controlled converter exceeds a preset change threshold. The model update unit is used to update the steady-state model of the converter arm current using the current load impedance value to obtain the predicted steady-state current value of the converter arm.

[0089] In this embodiment, the control output module specifically includes a protection judgment unit and a control command output unit. The protection judgment unit is used to determine whether the predicted steady-state current value of the converter bridge arm is greater than the preset protection threshold. If it is, the control command output unit sends a blocking pulse control command to the PWM controller. Otherwise, the control switches to the execution of the real-time acquisition module.

[0090] The converter protection and control device based on steady-state current prediction in this embodiment corresponds one-to-one with the converter protection and control method based on steady-state current prediction described above, and will not be repeated here.

[0091] This embodiment also provides an electronic device, including a processor and a memory, wherein the memory is used to store a computer program and the processor is used to execute the computer program to perform the above-described method.

[0092] It is understood that the method described in this embodiment can be executed by a single device, such as a computer or server, or it can be applied to a distributed scenario where multiple devices cooperate to complete the task. In a distributed scenario, one of the multiple devices may execute only one or more steps of the method described in this embodiment, and the multiple devices interact to complete the method. The processor can be implemented using a general-purpose CPU, microprocessor, application-specific integrated circuit, or one or more integrated circuits, and is used to execute relevant programs to implement the method described in this embodiment. The memory can be implemented using read-only memory (ROM), random access memory (RAM), static storage devices, and dynamic storage devices. The memory can store the operating system and other applications. When the method described in this embodiment is implemented through software or firmware, the relevant program code is stored in the memory and called and executed by the processor.

[0093] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described above.

[0094] Those skilled in the art will understand that the above embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create an implementation for the process. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A converter protection and control method based on steady-state current prediction, characterized in that the steps are as follows: include: Real-time acquisition of the output voltage / current of the controlled converter; The control parameter information of the PWM controller in the controlled converter and the output voltage of the controlled converter acquired in real time are input into the load impedance calculation model to determine whether the change value of the load impedance of the controlled converter exceeds a preset threshold. The load impedance calculation model is a relationship model between the load impedance in the converter and the output voltage / current and the control parameter information of the PWM controller. If it is determined that the change in the load impedance of the controlled converter exceeds the preset change threshold, the current load impedance value is used to update the steady-state model of the converter arm current to predict the steady-state current and obtain the predicted steady-state current value of the converter arm. The steady-state model of the converter arm current is a model of the relationship between the steady-state current value of the arm and the load impedance in the converter. Control commands are sent based on the predicted steady-state current value of the converter bridge arm to perform protection control on the controlled converter. Based on the system transfer function of the controlled converter system, the relationship expression between the load impedance in the converter and the output voltage / current of the converter, the inner loop transfer function of the PWM controller, and the outer loop PI transfer function of the PWM controller is constructed to obtain the load impedance calculation model. The controlled converter system includes the controlled converter and the PWM controller. The expression for the load impedance calculation model is as follows: in, For load impedance, This represents the active component of the output voltage / current. This is a reference value for the active component of the output voltage / current. For the outer loop transfer function of the PWM controller, This is the inner loop transfer function of the PWM controller. For converter bridge arm current, This is a reference value for the converter bridge arm current. This is the proportional gain of the PI controller in the inner loop. The integral coefficient of the PI controller in the inner loop is denoted as . This refers to the output filter inductance value in the converter. The proportional gain of the PI controller in the outer loop. The integral coefficient of the PI controller in the outer loop is denoted as . This is the capacitance value of the output filter capacitor in the converter; The output filter capacitor current in the converter arm current calculation model is approximated as 0 to represent the short-circuit condition of the tested converter system, thus obtaining the steady-state model of the converter arm current. The expression for the steady-state model of the converter arm current is: in, For the steady-state current of the converter bridge arm, The output voltage / current of the converter. This represents the load impedance in the converter.

2. The converter protection and control method based on steady-state current prediction according to claim 1, characterized in that, The protection control of the controlled converter based on the predicted steady-state current value of the converter arm includes: if the predicted steady-state current value of the converter arm is greater than a preset steady-state current threshold, then the pulse of the PWM controller is blocked.

3. The converter protection and control method based on steady-state current prediction according to claim 1, characterized in that, If the change in the load impedance of the controlled converter is determined to be less than the preset change threshold, the output voltage / current of the controlled converter will continue to be monitored in real time to determine the change in the load impedance of the controlled converter.

4. A converter protection and control device based on steady-state current prediction for use in the method described in any one of claims 1 to 3, characterized in that, include: The real-time acquisition module is used to acquire the output voltage / current of the controlled converter in real time. The load impedance change judgment module is used to input the control parameter information of the PWM controller in the controlled converter and the output voltage / current of the controlled converter in real time into the load impedance calculation model to determine whether the change value of the load impedance of the controlled converter exceeds a preset threshold. The load impedance calculation model is a relationship model between the load impedance in the converter and the output voltage / current and the control parameter information of the PWM controller. The steady-state current prediction module is used to update the steady-state model of the converter arm current to predict the steady-state current if the load impedance change judgment module determines that the change value of the load impedance of the controlled converter exceeds a preset change threshold. The predicted steady-state current value of the converter arm is obtained. The steady-state model of the converter arm current is a model of the relationship between the steady-state current value of the arm in the converter and the load impedance. The control output module is used to send control commands based on the predicted steady-state current value of the converter bridge arm to perform protection control on the controlled converter.

5. An electronic device comprising a processor and a memory, the memory being used to store a computer program, characterized in that, The processor is used to execute the computer program to perform the method as described in any one of claims 1 to 3.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method as described in any one of claims 1 to 3.

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