Converter load reduction shutdown method and device, power equipment and storage medium

Abstract

The application discloses a converter load reduction shutdown method and device, power equipment and a storage medium. The method comprises the following steps: when a shutdown instruction is received, a maximum torque capacity limit value is acquired; whether a preset load reduction shutdown condition is met is judged based on the maximum torque capacity limit value, and if yes, a load reduction shutdown action is performed; during the execution of the load reduction shutdown action, a motor magnetic field is weakened through a field weakening control strategy to reduce a motor terminal voltage. The application can avoid electrical impact and protection misoperation caused by rapid load reduction or direct machine cutting, realize full-process fault-free smooth shutdown under a high-speed working condition, and reduce the operation and maintenance cost of the whole machine.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a method, apparatus, power equipment, and storage medium for reducing the load and shutting down a converter. Background Technology

[0002] With the continuous increase in grid-connected capacity of wind power generation, the stable operation of doubly-fed variable speed wind turbines has become the key to reliable power supply of wind power systems. As the core control device between the generator and the grid, the converter's load reduction and shutdown control strategy under high speed and high torque conditions during generator acceleration or high-speed operation directly determines the operational safety and equipment lifespan of the wind power system.

[0003] Currently, existing wind power converters lack mature and reliable load reduction and shutdown control strategies under conditions of high unit speed and large torque. Traditional shutdown methods often directly perform rapid load reduction or tripping operations under these conditions, which can easily trigger faults such as DC bus overvoltage, torque surge, and current protection. This not only causes severe stress accumulation and electrical shock to power devices and control systems, but also significantly increases the overall operation and maintenance costs of the unit. Summary of the Invention

[0004] This invention provides a method, apparatus, power equipment, and storage medium for reducing the load and shutting down a converter, aiming to overcome the problem that existing wind power converters are prone to triggering faults when reducing the load and shutting down.

[0005] In a first aspect, embodiments of the present invention provide a converter load reduction shutdown method, the converter load reduction shutdown method comprising: Upon receiving a shutdown command, obtain the maximum torque capacity limit; Based on the maximum torque capacity limit, determine whether the preset load reduction and shutdown conditions are met. If they are met, then execute the load reduction and shutdown action. During the load reduction and shutdown operation, the motor magnetic field is weakened by a field weakening control strategy to reduce the terminal voltage.

[0006] Secondly, embodiments of the present invention also provide a converter load reduction and shutdown device, the device comprising: The calculation unit is used to obtain the maximum torque capacity limit when a stop command is received; The judgment unit determines whether the preset load reduction and shutdown conditions are met based on the maximum torque capacity limit. If the conditions are met, the load reduction and shutdown action is executed. During the execution of the load reduction and shutdown action, the control unit weakens the motor's magnetic field through a field weakening control strategy to reduce the terminal voltage.

[0007] Thirdly, embodiments of the present invention also provide a power device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described method.

[0008] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the above-described method.

[0009] This invention provides a method, apparatus, power equipment, and storage medium for converter load reduction shutdown. The method includes: upon receiving a shutdown command, obtaining a maximum torque capacity limit; determining whether preset load reduction shutdown conditions are met based on the maximum torque capacity limit; if met, executing a load reduction shutdown action; during the execution of the load reduction shutdown action, weakening the motor magnetic field through a field weakening control strategy to reduce the terminal voltage. This invention, by introducing a field weakening control strategy during the load reduction shutdown process, actively weakens the motor magnetic field to suppress the terminal voltage when the unit speed increases, leading to a voltage rise, thus avoiding DC bus overvoltage runaway; within the field weakening control range, it coordinates electromagnetic torque regulation and current control, avoiding electrical shocks and protection malfunctions caused by rapid load reduction or direct tripping, achieving a smooth, fault-free shutdown under high-speed conditions, and reducing overall machine maintenance costs. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a flowchart illustrating the converter load reduction and shutdown method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the first sub-process of the converter load reduction and shutdown method provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the second sub-process of the converter load reduction and shutdown method provided in the embodiment of the present invention; Figure 4 This is a schematic diagram of the third sub-process of the converter load reduction and shutdown method provided in the embodiment of the present invention; Figure 5 This is a schematic diagram of the fourth sub-process of the converter load reduction and shutdown method provided in the embodiment of the present invention; Figure 6 This is a schematic block diagram of the converter load reduction and shutdown device provided in an embodiment of the present invention; Figure 7This is a schematic block diagram of the power equipment provided in the embodiments of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] It should be understood that, when used in this specification and the appended claims, the terms “comprising” and “including” indicate the presence of the described features, integrals, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, operations, elements, components and / or collections thereof.

[0014] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0015] Please see Figure 1 , Figure 1 This is a flowchart illustrating the converter load reduction and shutdown method provided in this embodiment of the invention. In the control theory of doubly-fed induction generator (DFIG) wind turbines, the output capacity of the converter is subject to two insurmountable physical hardware limits: a current limit and a voltage limit, meaning the induced voltage of the motor cannot exceed the maximum voltage that the DC bus of the converter can withstand. When the unit performs a load reduction and shutdown at high speed, the electromagnetic torque drops sharply, causing the wind turbine to lose braking and its speed to rise uncontrollably, leading to a sharp increase in the rotor induced voltage. To suppress this voltage, this application proposes a converter load reduction and shutdown method, such as... Figure 1 As shown, the method includes steps S110 to S130.

[0016] S110: When a stop command is received, the maximum torque capacity limit is obtained.

[0017] In this embodiment of the invention, when the converter receives a routine load reduction and shutdown command from the wind power main control system via the communication bus, it immediately initiates the calculation process for the maximum torque capacity limit. This maximum torque capacity limit is the upper limit of hardware safety operation during the converter's load reduction and shutdown process. Its physical meaning is the torque value corresponding to the maximum active power that the grid-side module, the generator-side module, and the apparent power can stably bear under the current operating conditions. It is used to constrain the unit's output torque, preventing damage to power devices such as IGBTs and capacitors due to overload in any module. It is the core judgment basis for subsequent load reduction procedures, and the calculation results are stored in real-time in the converter's main control register for use in subsequent steps.

[0018] S120: Based on the maximum torque capacity limit, determine whether the preset load reduction and shutdown conditions are met. If they are met, execute the load reduction and shutdown action.

[0019] See Figure 2 In some feasible embodiments, step S120 may further include the following steps: S121, determine whether the real-time torque command value is greater than or equal to the maximum torque capability limit; S122, if the real-time torque command value is greater than or equal to the maximum torque capacity limit, then it is determined that the load reduction shutdown condition is met; S123, reduce the real-time torque command value until the real-time torque command value is less than the maximum torque capability limit.

[0020] In this embodiment of the invention, the converter acquires the real-time torque command value of the turbine issued by the wind power main control system. This command value is the target output torque of the turbine calculated by the main control system based on the current wind speed and pitch angle, and serves as a reference for the converter's torque control. The converter compares the acquired real-time torque command value with the maximum torque capacity limit. If the real-time torque command value is greater than or equal to the maximum torque capacity limit, it indicates that the current target torque of the turbine exceeds the converter's hardware safety range, and a load reduction process needs to be initiated. If the real-time torque command value is less than the maximum torque capacity limit, it indicates that the current torque is within the safety range, and the conventional shutdown logic is executed directly without load reduction.

[0021] For example, taking a 1.5MW doubly-fed wind turbine converter as an example, the maximum torque capacity limit is 11540 N·m, under two operating conditions: The real-time torque command value obtained by the converter is 12000 N·m. Since 12000 ≥ 11540, it is determined to be outside the safe range, triggering the load reduction process. The real-time torque command value obtained by the converter is 11000 N·m. Since 11000 < 11540, it is determined to be within the safe range, and the normal shutdown logic is executed.

[0022] S130, during the execution of the load reduction and shutdown action, the motor magnetic field is weakened by the field weakening control strategy to reduce the terminal voltage.

[0023] In this embodiment of the invention, as the load reduction process proceeds, the increase in unit speed leads to an increase in slip, which in turn causes a sharp rise in the induced voltage on the rotor side and at the generator terminals. When the voltage approaches the safety threshold of the converter, this embodiment actively intervenes with a field weakening control strategy. By injecting a reverse inductive reactive current (i.e., a field weakening current) into the motor rotor, a magnetic field opposite to the direction of the main magnetic field is generated, thereby actively weakening the air gap magnetic flux inside the motor, effectively suppressing the generator terminal voltage within a safe range, and avoiding DC bus overvoltage runaway.

[0024] If overspeed occurs during shutdown, for example, when the speed exceeds 130% of the preset speed, the main control unit, based on the converter load reduction flag, prevents the overspeed fault from being reported during this process to avoid motor runaway caused by converter shutdown. As the slip increases, the rotor voltage rises. The generator-side inductive reactive power is used to reduce the generator terminal voltage through field weakening, preventing bus runaway and ensuring that the unit does not report any faults during shutdown, thus promoting long-term safe and stable operation. Normal shutdown without any fault reports from the wind power converter during high-speed load reduction reduces the stress accumulation on power devices and the control system caused by frequent fault shutdowns. This improves the converter's operational reliability and lifespan, effectively reduces unplanned shutdowns and maintenance frequency, and thus lowers overall operation and maintenance costs.

[0025] In this embodiment, based on a voltage closed-loop field weakening control strategy, a controlled oscillation and impact process is introduced during the high-speed phase, enabling the unit to gradually release mechanical and electromagnetic energy during acceleration or high-speed operation, while simultaneously achieving orderly attenuation of power and torque. This strategy can effectively coordinate electromagnetic torque regulation and current control within the field weakening control range, avoiding electrical shocks and protection malfunctions caused by rapid load reduction or direct turbine tripping. Simultaneously, the stable and controllable shutdown process also helps improve unit availability, further enhancing the overall power generation efficiency of the wind turbine.

[0026] See Figure 3 In some embodiments, such as this embodiment, step S130 may include the following steps: S131, obtain the required bus voltage and the maximum set bus voltage; S132, calculate the first voltage deviation value based on the bus demand voltage and the bus maximum set voltage; S133, perform nonlinear processing on the first voltage deviation value to obtain a second voltage deviation value; S134, the second voltage deviation value is PI-regulated to generate a weak magnetic reactive power regulation amount; S135, Closed-loop regulation is performed based on the aforementioned field weakening reactive power regulation amount to weaken the motor magnetic field.

[0027] In this embodiment of the invention, this step addresses the problem of a sudden increase in wind turbine speed, increased slip, and rising rotor voltage caused by torque decay during load reduction, which can easily lead to DC bus overvoltage and runaway. It is executed synchronously and in real-time with the load reduction and speed monitoring process, initiating regulation only when the bus voltage shows an abnormal upward trend. Through the closed-loop logic of the turbine-side field weakening control, the rise in rotor voltage and bus voltage is suppressed at its source, preventing bus overvoltage from triggering protection faults and ensuring a fault-free shutdown and load reduction process. The following is a detailed explanation: The bus demand voltage is the actual real-time voltage requirement of the DC bus under the current operating conditions of the converter (rapid speed increase, increased slip). It is a core real-time parameter reflecting the operating status of the bus voltage. The maximum set voltage of the bus is a fixed configuration parameter, preset based on the hardware tolerance capabilities of the converter's IGBTs, capacitors, and other power devices. It serves as a benchmark value for determining whether there is an overvoltage risk on the bus. It can be understood that subsequent deviation calculations, nonlinear processing, and adjustment actions are triggered only when the collected bus demand voltage exceeds the maximum set voltage. If the bus demand voltage is within the safe range, this control loop only monitors and does not perform any adjustment operations.

[0028] The bus demand voltage can be calculated from the generated voltage of the generator-side converter to improve the control response speed and accuracy. First, the generated voltage amplitudes of the generator-side d-axis and q-axis are obtained, and the magnitude of the generated voltage (i.e., the square root of the sum of the squares of the d-axis and q-axis voltage amplitudes) is calculated. After low-pass filtering, the bus demand voltage is calculated by combining the reference voltage and a preset conversion factor, as shown in the following formula: iTmp=sqrt (D-axis action value on the machine side) 2 +Q-axis action on the machine side 2 (1) Where iTmp is the magnitude of the transmitted voltage, and sqrt is the calculation method for the magnitude. After low-pass filtering the magnitude of the transmitted voltage to obtain V1, the formula for calculating the bus demand voltage is as follows: V2 = V1 * V base / 4096*1.414(2) Where V2 is the required bus voltage, V base The reference voltage is 1.414, and the conversion factor is 1.414.

[0029] The maximum set voltage of the bus is a safety upper limit preset based on the hardware tolerance capability of the converter's power devices. It can be calculated by reading the configured maximum percentage of the bus voltage setting and the reference voltage. V dc =K*V base (3) Among them, V dc The maximum set voltage for the busbar, K is the maximum percentage of the set busbar voltage (e.g., 105% or 1.05, representing the limit of the hardware's withstand voltage), V base If the reference voltage is used, the formula for calculating the first voltage deviation value is as follows: First voltage deviation value = V dc * (1 - given coefficient for the weak magnetic busbar) - V2 (4) The given coefficient for the weakening magnetic bus is a preset safety margin parameter. The calculated first voltage deviation value needs to undergo preliminary upper and lower limit processing (e.g., a limit range of [-3000, 3000]) to prevent numerical overflow under extreme operating conditions. When the first voltage deviation value is negative, it means that the required bus voltage on the machine side has exceeded the maximum set voltage after considering the safety margin, and there is a risk of overvoltage; when it is positive, it means that the voltage is within the safe range.

[0030] After obtaining the first voltage deviation value, it can be preprocessed, that is, nonlinear processing can be performed. The core purpose of nonlinear processing of the first voltage deviation value is to eliminate the interference of small voltage deviations caused by power grid fluctuations and mechanical vibrations, avoid meaningless frequent magnetic weakening adjustments that cause system oscillations, filter invalid deviation signals, and only adjust the effective overvoltage deviations to improve the stability and accuracy of bus voltage regulation.

[0031] Nonlinear processing can be categorized and handled according to the magnitude of the deviation: For small negative deviations: directly limit the amplitude to zero, shield the adjustment action, and avoid reverse adjustment; For small positive deviations: set as adjustment dead zone, set to zero to prevent adjustment from being triggered, and filter out invalid fluctuations; For effective overvoltage deviation: scale by a fixed ratio to reduce the adjustment gain, prevent excessive single adjustment from causing voltage reversal, and avoid secondary failures.

[0032] The second voltage deviation value obtained after nonlinear processing provides a clean and effective deviation signal for subsequent PI regulation, ensuring the stability of the regulation logic.

[0033] The second voltage deviation value is converted into a field weakening reactive power control command that the converter can execute through the PI (proportional-integral) regulation algorithm, namely the field weakening reactive power regulation amount (physical form is the setpoint / regulation amount of the inductive reactive current on the machine side).

[0034] The synergistic effect of the two stages in PI regulation ensures rapid voltage regulation and zero steady-state error. Proportional control: Based on the amplitude of the second voltage deviation value, quickly output the corresponding proportional reactive power regulation to achieve rapid response to bus overvoltage and timely suppress the voltage rise trend; Integral stage: Eliminates static voltage deviation caused by proportional regulation, continuously fine-tunes reactive power regulation, and ensures that the bus voltage can stably return to a safe range without residual deviation.

[0035] The generated field weakening reactive power regulation is the direct basis for the execution of the field weakening control on the machine side, and its value is positively correlated with the amplitude of the bus overvoltage deviation.

[0036] By employing a logic of reactive current injection, magnetic field weakening, and voltage suppression, the problem of bus overvoltage caused by increased slip is fundamentally resolved. Furthermore, the entire process is a closed-loop regulation, achieving continuous and precise control of the bus voltage. The specific execution logic is as follows: The converter sends an inductive reactive current command to the machine-side module based on the generated field weakening reactive power regulation action. After receiving the command, the generator-side module precisely injects an inductive reactive current of the corresponding amplitude into the generator rotor, thereby weakening the air gap magnetic field of the generator through the field weakening control principle. After the generator air gap magnetic field is weakened, its terminal voltage will decrease synchronously, which will fundamentally suppress the problem of rotor voltage rise caused by increased slip, thereby achieving the reduction of DC bus voltage. During the regulation process, the converter will collect parameters such as bus voltage, generator terminal voltage, and inductive reactive current in real time, continuously compare the actual demand voltage of the bus with the maximum set voltage, and adjust the field weakening reactive power regulation amount in real time according to the dynamic changes of the deviation until the demand voltage of the bus falls back below the maximum set voltage, thus completing this voltage regulation. If the bus voltage shows an overvoltage trend again, the above process will be repeated to achieve closed-loop voltage regulation.

[0037] The above steps can avoid the problem of bus overvoltage caused by the speed surge during load reduction, and achieve no overvoltage fault or overspeed fault during high-speed load reduction shutdown. At the same time, it protects power devices such as converter IGBTs and capacitors from overvoltage impact, and improves the safety and stability of the shutdown process.

[0038] See Figure 4 In some embodiments, step S133 may include the following steps: S1331, Obtain the first voltage deviation value; S1332, if the first voltage deviation value is less than the first preset threshold, then the first voltage deviation value is subjected to amplitude limiting processing to obtain the second voltage deviation value. S1333, if the first voltage deviation value is greater than or equal to the first preset threshold and less than the second preset threshold, then the first voltage deviation value is set to the initial value to obtain the second voltage deviation value. S1334, if the first voltage deviation value is greater than or equal to the second preset threshold, then the first voltage deviation value is scaled to obtain the second voltage deviation value.

[0039] In this embodiment of the invention, the first preset threshold, the second preset threshold, and the initial value can be calibrated according to the system. For example, the first preset threshold is 0, the second preset threshold is 200, and the initial value is 0.

[0040] First voltage deviation value < 0: This indicates that the required voltage of the bus is higher than the maximum set voltage of the bus, and there is an overvoltage risk. The first voltage deviation value is limited (limiting range [-3000, 3000]), and the negative value is retained to trigger field weakening regulation, which reduces the generator terminal voltage by generating inductive reactive power. 0≤First voltage deviation <200: This is a normal, minor fluctuation in the bus voltage, which is the adjustment dead zone. Setting it to 0 will not trigger any field weakening adjustment. A first voltage deviation value ≥ 200 indicates an effective voltage anomaly. Weak magnetic regulation needs to be activated to scale the first voltage deviation value (e.g., divide by 10) to reduce the regulation gain, prevent overshoot, and avoid voltage reversal due to excessive single adjustment.

[0041] For example, taking a maximum bus voltage of 800V as an example (internally represented as 8000, i.e., ×10 scaling), there are three operating conditions: The busbar requires a voltage of 810V (the system indicates 8100). The first voltage deviation value is 8000-8100=-100<0. Amplitude limiting is performed, and the negative value is retained to obtain the second voltage deviation value of -100. The field weakening regulation is started to reduce the generator terminal voltage by generating inductive reactive power. The busbar requires a voltage of 790V (the system indicates 7900V). The first voltage deviation value is 8000-7900=100, which satisfies 0≤100<200. The value is set to 0, and the second voltage deviation value is obtained as 0. The field weakening regulation is not started. The busbar requires a voltage of 770V (the system indicates 7700V). The first voltage deviation value is 8000-7700=300≥200. Scale (300 / 10=30) to obtain the second voltage deviation value of 30, and start the field weakening adjustment.

[0042] See Figure 5 In some embodiments, such as in the embodiments of the present invention, step S110 may include the following steps: S111, calculate the maximum functional capacity of the grid-side module, the maximum functional capacity of the machine-side module, and the maximum functional capacity of the apparent power, respectively; S112, the minimum value among the maximum working capacity value, the maximum working capacity value of the machine-side module, and the maximum working capacity value of the apparent power is taken as the maximum torque capacity limit value.

[0043] In this embodiment of the invention, the maximum active power capacity of the grid-side module can be calculated based on the rated active power of the grid-side module and the real-time reactive power input of the grid side, reflecting the maximum capacity of the grid-side converter to deliver electrical energy to the grid. The calculation formula is as follows: (5) (6) Among them, P rec_total P is the maximum functional capacity calculated for the network-side module. rec For the basic functional capacity calculation value of the network-side module, I rec_capacity For the rated current capability of the grid-side module, I rec_Q V is the setpoint for the grid-side reactive current. gd P represents the d-axis voltage of the power grid (in a synchronous rotating coordinate system). n Let be the rated active power of the grid-side module, and s be the slip of the doubly-fed generator, defined as s = (n sync -n rotor ) / n sync n sync For synchronous speed, n rotor This represents the actual rotor speed.

[0044] The maximum active power capacity of the generator-side module can be calculated based on the rated active power of the generator-side module and the real-time reactive power input (including inductive reactive current for weakening magnetic field, capacitor current, and excitation current). It reflects the maximum capacity of the generator-side converter to absorb electrical energy from the generator. The calculation formula is as follows: (7) (8) Among them, P Inv_total P is the maximum work capacity calculated by the machine-side module. Inv For the calculation value of the basic functional capacity of the machine-side module, I Inv_capacity For the rated current capability of the machine-side module, I Inv _Q is the setpoint for the reactive current on the machine side (including the inductive reactive current for weakening the magnetic field, the capacitive current, and the excitation current), V gq This represents the q-axis voltage of the power grid (in a synchronous rotating coordinate system).

[0045] The maximum apparent power capacity can be calculated based on the overall rated apparent power and real-time power factor of the converter, reflecting the upper limit of the overall active power carrying capacity of the converter. The calculation formula is as follows: (9) Among them, P stotal S represents the maximum total work capacity under the apparent power limit. lmt Q is the apparent power limit of the converter. setThis is the setpoint for the reactive power of the converter.

[0046] The minimum value among the three is taken as the maximum torque capacity limit to ensure that all core modules of the converter operate within a safe range. The calculation formula is as follows: (10) For example, taking a 1.5MW doubly fed wind turbine converter as an example, its rated operating parameters are: grid-side module rated active power 1600kW, turbine-side module rated active power 1650kW, and overall converter rated apparent power 1500kVA.

[0047] Under real-time operating conditions, the maximum power capacity of the grid-side module is 1500kW, the maximum power capacity of the machine-side module is 1550kW, and the maximum apparent power capacity is 1450kW. Taking the minimum of the three values, 1450kW, as the maximum working capacity limit, and combining it with the current unit speed of 1200rpm, the maximum torque capacity limit is calculated to be approximately 9550×1450 / 1200≈11540N·m using the formula torque=9550×power / speed.

[0048] In some embodiments, such as in the embodiments of the present invention, the following steps may be included before step S110: Obtain the low voltage ride-through configuration parameters and switch the low voltage ride-through configuration parameters from a writable register to a read-only register to lock the low voltage ride-through configuration parameters.

[0049] In this embodiment of the invention, the low-voltage ride-through configuration parameters are the core parameters for the converter to cope with grid voltage dips. These parameters include, but are not limited to, voltage dip thresholds, reactive power support coefficients, PI regulation parameters, and fault ride-through duration. These parameters are stored by default in the converter's writable registers and support dynamic adjustment when grid operating conditions change. Locking these parameters before load reduction shutdown is to prevent small grid fluctuations during load reduction from triggering the low-voltage ride-through configuration parameter self-tuning, or from erroneous modifications to the parameters during background debugging, which could interfere with the calculation logic of the maximum torque capacity limit and subsequent load reduction control. Locking is a software-level register state switch with no hardware operation, and the locked state only lasts until the load reduction shutdown is completed, after which it automatically returns to the writable state.

[0050] For example, after receiving a shutdown command, the converter immediately reads the low voltage ride-through configuration parameter register with addresses 0x200-0x20F and switches it from 0x01 (writable state) to 0x00 (read-only state). The register state is automatically restored to 0x01 after the load reduction is completed. Throughout the process, even if the grid voltage drops slightly, the low voltage ride-through configuration parameters are not modified.

[0051] Figure 6This is a schematic block diagram of a converter load reduction and shutdown device 100 provided in an embodiment of the present invention. Figure 6 As shown, corresponding to the above-described converter load reduction and shutdown method, the present invention also provides a converter load reduction and shutdown device 100. This converter load reduction and shutdown device 100 includes a unit for performing the above-described converter load reduction and shutdown method. Specifically, please refer to... Figure 6 The converter load reduction and shutdown device 100 includes a calculation unit 110, a judgment unit 120, and a control unit 130.

[0052] The calculation unit 110 is used to obtain the maximum torque capacity limit when a stop command is received. The judgment unit 120 is used to determine whether the preset load reduction and shutdown conditions are met based on the maximum torque capacity limit. If the conditions are met, the load reduction and shutdown action is executed. The control unit 130 is used to reduce the motor magnetic field and lower the terminal voltage by means of a field weakening control strategy during the execution of the load reduction and shutdown action.

[0053] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the above-mentioned converter load reduction and shutdown device and each unit can be referred to the corresponding description in the foregoing method embodiments. For the sake of convenience and brevity, it will not be repeated here.

[0054] The aforementioned converter load reduction and shutdown device can be implemented as a computer program, which can be used in, for example... Figure 7 It operates on the power equipment shown.

[0055] Please see Figure 7 , Figure 7 This is a schematic block diagram of a power device provided in an embodiment of this application. The power device 600 includes a processor 602, a memory, and a network interface 605 connected via a system bus 601. The memory may include a non-volatile storage medium 603 and internal memory 604.

[0056] The non-volatile storage medium 603 may store an operating system 6031 and a computer program 6032. When the computer program 6032 is executed, it causes the processor 602 to execute a converter load reduction and shutdown method.

[0057] The processor 602 provides computing and control capabilities to support the operation of the entire power equipment 600.

[0058] The internal memory 604 provides an environment for the operation of the computer program 6032 in the non-volatile storage medium 603. When the computer program 6032 is executed by the processor 602, the processor 602 can execute a converter load reduction and shutdown method.

[0059] This network interface 605 is used for communication with other devices. Those skilled in the art will understand that... Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the power equipment 600 to which the present application is applied. The specific power equipment 600 may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0060] It should be understood that in the embodiments of this application, the processor 602 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0061] It will be understood by those skilled in the art that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program may be stored in a storage medium, which is a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the process steps of the embodiments of the above methods.

[0062] Therefore, the present invention also provides a storage medium. This storage medium can be a computer-readable storage medium. The storage medium stores a computer program. When executed by a processor, the computer program implements any embodiment of the above-described converter load reduction and shutdown method.

[0063] The storage medium can be any computer-readable storage medium capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory (ROM), magnetic disk, or optical disk.

[0064] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0065] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of each unit is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0066] The steps in the method of this invention can be adjusted, merged, or reduced in order according to actual needs. The units in the device of this invention can be merged, divided, or reduced according to actual needs. Furthermore, the functional units in the various embodiments of this invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0067] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a converter to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0068] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0069] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Since these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for reducing load and shutting down a converter, characterized in that, The converter load reduction and shutdown method includes: Upon receiving a shutdown command, obtain the maximum torque capacity limit; Based on the maximum torque capacity limit, determine whether the preset load reduction and shutdown conditions are met. If they are met, execute the load reduction and shutdown action. When performing the load reduction and shutdown action, the motor magnetic field is weakened by a field weakening control strategy to reduce the terminal voltage.

2. The method as described in claim 1, characterized in that, The step of reducing the motor's magnetic field to lower the terminal voltage through a field weakening control strategy includes: Obtain the required bus voltage and the maximum set bus voltage; Calculate the first voltage deviation value based on the required voltage of the bus and the maximum set voltage of the bus; The first voltage deviation value is subjected to nonlinear processing to obtain the second voltage deviation value; The second voltage deviation value is PI-regulated to generate a weak magnetic reactive power regulation amount; Closed-loop regulation is performed based on the aforementioned magnetic field weakening reactive power regulation effect to weaken the motor magnetic field.

3. The method as described in claim 2, characterized in that, The step of performing nonlinear processing on the first voltage deviation value to obtain the second voltage deviation value includes: Obtain the first voltage deviation value; If the first voltage deviation value is less than the first preset threshold, then the first voltage deviation value is subjected to amplitude limiting processing to obtain the second voltage deviation value.

4. The method as described in claim 3, characterized in that, After the step of obtaining the first voltage deviation value, the method further includes: If the first voltage deviation value is greater than or equal to the first preset threshold and less than the second preset threshold, then the first voltage deviation value is set to the initial value to obtain the second voltage deviation value. If the first voltage deviation value is greater than or equal to the second preset threshold, then the first voltage deviation value is scaled to obtain the second voltage deviation value.

5. The method as described in claim 1, characterized in that, The step of obtaining the maximum torque capacity limit includes: Calculate the maximum functional capacity of the grid-side module, the maximum functional capacity of the machine-side module, and the maximum functional capacity of the apparent power, respectively. The minimum value among the maximum working capacity, the maximum working capacity of the machine-side module, and the maximum working capacity of the apparent power is taken as the maximum torque capacity limit.

6. The method as described in claim 1, characterized in that, The step of determining whether the preset load reduction and shutdown conditions are met based on the maximum torque capacity limit, and then performing the load reduction and shutdown action if the conditions are met, includes: Determine whether the real-time torque command value is greater than or equal to the maximum torque capability limit; If the real-time torque command value is greater than or equal to the maximum torque capacity limit, then the load reduction shutdown condition is determined to be met. Reduce the real-time torque command value until it is less than the maximum torque capability limit.

7. The method as described in claim 1, characterized in that, Before the step of obtaining the maximum torque capability limit, the method further includes: Obtain the low voltage ride-through configuration parameters and switch the low voltage ride-through configuration parameters from a writable register to a read-only register to lock the low voltage ride-through configuration parameters.

8. A converter load reduction and shutdown device, characterized in that, The device includes: The calculation unit is used to obtain the maximum torque capacity limit when a stop command is received; The judgment unit determines whether the preset load reduction and shutdown conditions are met based on the maximum torque capacity limit. If the conditions are met, the load reduction and shutdown action is executed. During the execution of the load reduction and shutdown action, the control unit weakens the motor's magnetic field through a field weakening control strategy to reduce the terminal voltage.

9. An electrical device, characterized in that, The power equipment includes a memory and a processor connected to the memory; the memory is used to store a computer program; the processor is used to run the computer program stored in the memory to perform the steps of the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, can implement the steps of the method as described in any one of claims 1-7.

Images