New energy unit transient control method and device, computer equipment and storage medium

Abstract

The invention provides a new energy unit transient control method and device, computer equipment and a storage medium. The method comprises the following steps: judging whether a control condition is met or not when entering a transient process, and if so, determining an initial instruction value according to a phase-locked loop output frequency change rate, a reactive current instruction value and an active detection value, the initial instruction value is adjusted according to the product of the difference between the phase-locked loop output frequency and the power grid frequency detection value and the additional frequency damping coefficient to obtain a final instruction value, and finally the final instruction value serves as an active power instruction value to be issued to the new energy unit. According to the scheme, reactive current control of an original unit is reserved, active power control is added, fine adjustment of the system is achieved, it is guaranteed that the output power of the new energy unit is accurate and controllable, meanwhile, the requirement of a grid-connected guide rule for the output current of the unit is met, the off-grid problem caused by large-amplitude deviation of the output frequency of the unit is avoided, and the system reliability is improved. And the grid-connected operation transient stability of the unit is improved.

Description

Technical Field

[0001] The present application relates to the technical field of transient control of power systems, and in particular to a method, device, computer equipment and storage medium for transient control of new energy units. Background Art

[0002] With the large-scale grid connection of new energy sources with power electronic converter interfaces, the impact of new energy on the safety and stability of the power system is increasing. In view of this, power systems in different regions have put forward requirements such as fault ride-through for new energy units in the grid connection guidelines, clarified the active and reactive output range of new energy during faults, and standardized the dynamic output characteristics of new energy.

[0003] Grid-connected new energy units mainly rely on phase-locked loops to achieve synchronization with the power grid. The phase-locked loop uses the grid connection point voltage as input to calculate the grid frequency and grid connection point voltage phase, thereby providing a reference angle for the vector control of the power electronic converter. The frequency and phase calculated and output by the phase-locked loop determine the frequency and phase of the electrical quantity injected into the grid by the new energy unit under the vector control mode. When a serious fault such as a short circuit occurs in the grid, the new energy unit enters fault ride-through. Since the grid connection point voltage is low at this time and is greatly affected by the unit output, the new energy unit is prone to a large deviation in its own output frequency, which in turn triggers the protection action and causes the unit to be disconnected from the grid, affecting the safety and stability of the system.

[0004] Some studies have proposed a method to lock the phase-locked loop during a power grid fault, that is, to limit the output frequency of the phase-locked loop to near the rated frequency of the power grid, thereby eliminating the impact of the phase-locked loop dynamics on stability. Other studies have proposed an active power synchronization control strategy without a phase-locked loop, which simulates the change law of the potential inside the synchronous generator under the power grid fault state and improves the synchronous operation stability of the unit.

[0005] However, in order to eliminate the impact of the dynamics of the phase-locked loop on stability, the method of locking the phase-locked loop artificially limits the output frequency of the phase-locked loop to near the rated frequency of the power grid, resulting in the unit being unable to accurately detect the actual grid frequency and voltage phase, making the unit vector control lack an accurate phase reference. This method will increase the control deviation of the active power and reactive power of the new energy unit. In severe cases, the power will be in an uncontrollable state due to the failure of the power decoupling control of the unit. The active power synchronization control method without a phase-locked loop, due to the lack of the grid voltage phase provided by the phase-locked loop, makes it difficult for the new energy unit to output the specified reactive current in accordance with the grid connection guidelines during the transient process. Summary of the invention

[0006] The purpose of the present application is to solve at least one of the above-mentioned technical defects, and in particular to provide a transient control scheme for new energy units that can add active power control on the basis of not changing the reactive current control of the unit, so as to ensure that the output power of the new energy unit is accurately controllable while meeting the grid-connected guidelines for the unit output requirements.

[0007] In a first aspect, the present application provides a method for transient control of a new energy generator set, which is applied to a new energy generator set that is synchronized with a power grid through a phase-locked loop. The method for transient control of a new energy generator set includes:

[0008] When entering the transient process, determine whether the control conditions are met;

[0009] If yes, then determine the initial command value according to the phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment;

[0010] According to the product of the difference between the phase-locked loop output frequency at the current moment and the power grid frequency detection value at the current moment and the additional frequency damping coefficient, the initial command value is adjusted to obtain the final command value;

[0011] The final command value is sent to the new energy unit as the active power command value.

[0012] In one embodiment, the initial command value is determined according to the phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment, including:

[0013] The phase-locked loop output frequency change rate at the current moment and the previous moment, the reactive current command value at the current moment, and the active current detection value at the current moment are input into the first expression to obtain the initial command value; the first expression is:

[0014]

[0015] in, is the initial instruction value, is the active power detection value at the current moment, is the reactive current command value at the current moment, k i is the phase-locked loop integral gain, are the phase-locked loop output frequencies at the current moment and the previous moment respectively, are the times corresponding to the current moment and the previous moment respectively, It is the rate of change of the phase-locked loop output frequency between the current moment and the previous moment.

[0016] In one embodiment, the initial command value is adjusted according to the product of the difference between the current phase-locked loop output frequency and the current power grid frequency detection value and the additional frequency damping coefficient to obtain the final command value, including:

[0017] The current phase-locked loop output frequency, the current grid frequency detection value and the initial command value are input into the second expression to obtain the final command value; the second expression includes:

[0018]

[0019] in, is the final instruction value, is the current power grid frequency detection value, K d is the additional frequency damping coefficient; the additional frequency damping coefficient satisfies:

[0020]

[0021] Among them, k p is the phase-locked loop proportional gain, is the voltage amplitude of the grid connection point of the new energy unit at the current moment, L g is the inductance between the new energy unit and the grid connection point, R g is the resistance value between the new energy unit and the grid connection point, is the d-axis component of the phase-locked loop output voltage at the current moment.

[0022] In one embodiment, determining whether the control condition is satisfied includes:

[0023] Determine the depth of grid voltage drop;

[0024] If the grid voltage drop depth is greater than the set threshold, it is determined that the control condition is met.

[0025] In one embodiment, the threshold is set to 50%.

[0026] In one embodiment, the control model for synchronization between the new energy unit and the power grid is:

[0027]

[0028] in, is the reactive current command value of the new energy unit, k i is the phase-locked loop integral gain, is the phase-locked loop output frequency, is the active power command value of the new energy unit, P o is the active power detection value of the new energy unit, k p is the proportional gain of the phase-locked loop, V gis the voltage amplitude of the grid connection point of the new energy unit, ω g is the power grid frequency detection value, L g is the inductance between the new energy unit and the grid connection point, u od is the d-axis component of the phase-locked loop output voltage, R g is the resistance value between the new energy unit and the grid connection point, is the angle between the dq synchronous rotating coordinate system and the system common rotating coordinate system, is the deflection angle, .

[0029] In one embodiment, the transient process includes a power grid short circuit fault.

[0030] In a second aspect, the present application provides a transient control device for a new energy generator set, which is applied to a new energy generator set that is synchronized with a power grid through a phase-locked loop. The transient control device for the new energy generator set includes:

[0031] A judgment module is used to judge whether the control conditions are met when entering a transient process;

[0032] The first processing module is used to determine the initial command value according to the phase-locked loop output frequency change rate at the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment when the control condition is met;

[0033] The second processing module is used to adjust the initial command value according to the product of the difference between the phase-locked loop output frequency at the current moment and the power grid frequency detection value at the current moment and the additional frequency damping coefficient to obtain the final command value;

[0034] The sending module is used to send the final command value as the active power command value to the new energy unit.

[0035] In a third aspect, the present application provides a computer device comprising one or more processors and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the steps of the transient control method of the new energy unit in any of the above-mentioned embodiments are executed.

[0036] In a fourth aspect, the present application provides a storage medium storing computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the transient control method of the new energy unit in any of the above-mentioned embodiments.

[0037] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0038] Based on the transient control method of the new energy unit in this scheme, it is judged whether the control conditions are met when entering the transient process. If they are met, the initial command value is determined according to the phase-locked loop output frequency change rate, reactive current command value and active detection value, and then the initial command value is adjusted according to the product of the difference between the phase-locked loop output frequency and the grid frequency detection value and the additional frequency damping coefficient to obtain the final command value, and finally the final command value is sent to the new energy unit as the active power command value. This scheme retains the reactive current control of the original unit and adds active power control, realizing the fine adjustment of the system, ensuring that the output power of the new energy unit is accurate and controllable while meeting the requirements of the grid-connected guidelines for the unit output current, avoiding the problem of disconnection caused by a large deviation in the unit's own output frequency, and improving the transient stability of the unit's grid-connected operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 This is a flow chart of a transient control method for a new energy generator set in one embodiment of the present application;

[0041] Figure 2 An internal structure diagram of a computer device provided for one embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] This application provides a transient control method for a new energy generator set, which is applied to a new energy generator set that is synchronized with a power grid through a phase-locked loop. Figure 1 The transient control method of the new energy unit includes steps S102 to S108.

[0044] S102, when entering the transient process, determine whether the control conditions are met.

[0045] It can be understood that the transient process refers to the process in which the power system connected to the new energy unit transitions from one stable state to another stable state. The transient process may include a short circuit fault in the power system. The control condition is a standard set to determine whether it is necessary to start the transient control method of the new energy unit in this embodiment.

[0046] In the process of new energy units synchronizing with the power grid through a phase-locked loop, various interferences or abnormal conditions may occur, causing the system to enter a transient process. At this time, it is necessary to determine whether the control conditions are met to decide whether to start the transient control method. If the control conditions are not met, the system can continue to operate in a normal manner. The purpose of determining whether the control conditions are met is to ensure that the transient control method is started only when necessary, to avoid unnecessary control actions, and to improve the stability and reliability of the system.

[0047] To determine whether the control condition is met, the depth of the grid voltage drop can be determined first. The control condition is determined to be met when the grid voltage drop depth is greater than the set threshold. The grid voltage drop depth is used to reflect the degree to which the power frequency voltage at a certain point in the power system is reduced relative to the rated value. In the process of new energy units synchronizing with the grid through a phase-locked loop, the stability of the grid voltage is crucial to the operation of the unit. When the grid voltage drops, the output frequency of the new energy unit may be unstable. By determining the grid voltage drop depth, the changes in the grid voltage can be understood in a timely manner. When the grid voltage drop depth is greater than the set threshold, it means that a large fault or interference has occurred in the grid. At this time, it is determined that the control condition is met, and the transient control method is started. Active power control can be added on the basis of not changing the reactive current control of the unit to stabilize the output frequency of the unit and avoid the occurrence of off-grid problems. In one embodiment, the threshold is set to 50%.

[0048] S104: If yes, determine the initial command value according to the phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment.

[0049] It can be understood that a phase-locked loop is an electronic circuit that can achieve phase locking and is used in new energy units to synchronize with the power grid. The frequency change rate refers to the change in frequency per unit time. The reactive current command value refers to the set value of the reactive current output by the new energy unit. The active detection value refers to the measured value of the active power actually output by the new energy unit. The initial command value is an intermediate value obtained through a specific calculation during the transient control process, which is used for subsequent adjustments and determination of the final active power command value.

[0050] The control model of the new energy unit in this embodiment is:

[0051]

[0052] in, is the reactive current command value of the new energy unit, k i is the phase-locked loop integral gain, ω 0 is the phase-locked loop output frequency, is the active power command value of the new energy unit, P o is the active power detection value of the new energy unit, k p is the proportional gain of the phase-locked loop, V g is the voltage amplitude of the grid connection point of the new energy unit, ω g is the power grid frequency detection value, L g is the inductance between the new energy unit and the grid connection point, u od is the d-axis component of the phase-locked loop output voltage, R g is the resistance value between the new energy unit and the grid connection point, is the angle between the dq synchronous rotating coordinate system and the system common rotating coordinate system, is the deflection angle, .

[0053] In this model, the first two terms on the right side of the equal sign are combined into one term, which can be regarded as the deviation between the command value and the actual value of the active power of the new energy unit, which can be called the active power deviation term ΔP. The latter term is the damping term related to the output frequency of the new energy unit, which can be simplified as D(ω 0 -ω g ). The initial command value is the active power command value obtained by adjusting only the active power deviation term. The initial command value can reduce the active power deviation term ΔP to suppress the change of the phase-locked loop output frequency by quickly adjusting the unit active power command during the transient process.

[0054] S106, adjusting the initial command value according to the product of the difference between the current phase-locked loop output frequency and the current power grid frequency detection value and the additional frequency damping coefficient to obtain a final command value.

[0055] It can be understood that the grid frequency detection value is a measurement of the actual operating frequency of the grid. The additional frequency damping coefficient is a parameter used to adjust the active power command value to stabilize the frequency. The final command value is the adjusted active power command value, which is used to be sent to the new energy unit for control. Since only the active power deviation term is considered in the initial command value. If the unit active power command value is continuously greater than or less than the actual active power output value, it will cause the output frequency ω of the new energy unit. 0 Continuously increase or decrease, which will cause the unit to become unstable. However, if only the frequency damping term is considered, if its value is negative, it will cause the output frequency ω 0Oscillation divergence will also cause the unit to become unstable. In step S106, a gain damping term is added to the initial command value to offset the above D(ω 0 -ω g ) is negative. Therefore, the gain damping term is positive over the entire operating frequency band to provide positive damping.

[0056] S108: Send the final command value as the active power command value to the new energy generator set.

[0057] It can be understood that the active power command value is a set value for the active power output of the new energy unit. Sending down means transmitting the command value to the control system of the new energy unit to realize the active power control of the unit. The control of reactive current in the new energy unit remains similar to that in the traditional phase-locked loop control. This embodiment adds active power control on the basis of not changing the reactive current control of the unit.

[0058] Based on the transient control method of the new energy unit in this scheme, it is judged whether the control conditions are met when entering the transient process. If they are met, the initial command value is determined according to the phase-locked loop output frequency change rate, reactive current command value and active detection value, and then the initial command value is adjusted according to the product of the difference between the phase-locked loop output frequency and the grid frequency detection value and the additional frequency damping coefficient to obtain the final command value, and finally the final command value is sent to the new energy unit as the active power command value. This scheme retains the reactive current control of the original unit and adds active power control, realizing the fine adjustment of the system, ensuring that the output power of the new energy unit is accurate and controllable while meeting the requirements of the grid-connected guidelines for the unit output current, avoiding the problem of disconnection caused by a large deviation in the unit's own output frequency, and improving the transient stability of the unit's grid-connected operation.

[0059] In one embodiment, the initial command value is determined according to the phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment, including:

[0060] The phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active current detection value at the current moment are input into the first expression to obtain the initial command value. The first expression is:

[0061]

[0062] in, is the initial instruction value, is the active power detection value at the current moment, is the reactive current command value at the current moment, k i is the phase-locked loop integral gain, are the phase-locked loop output frequencies at the current moment and the previous moment respectively, are the times corresponding to the current moment and the previous moment respectively, is the rate of change of the phase-locked loop output frequency between the current moment and the previous moment. It can be understood that the first expression is based on the above control model and ignores In the case of item, the active power command value that makes the frequency change rate 0.

[0063] In one embodiment, the initial command value is adjusted according to the product of the difference between the current phase-locked loop output frequency and the current power grid frequency detection value and the additional frequency damping coefficient to obtain the final command value, including:

[0064] The current phase-locked loop output frequency, the current grid frequency detection value and the initial command value are input into the second expression to obtain the final command value. The second expression includes:

[0065]

[0066] in, is the final instruction value, is the current power grid frequency detection value, K d is the additional frequency damping coefficient. The additional frequency damping coefficient satisfies:

[0067]

[0068] Among them, k p is the phase-locked loop proportional gain, is the voltage amplitude of the grid connection point of the new energy unit at the current moment, L g is the inductance between the new energy unit and the grid connection point, R g is the resistance value between the new energy unit and the grid connection point, is the d-axis component of the phase-locked loop output voltage at the current moment. It can be understood that the second expression is a reconsideration based on the above control model. After the item, The influence of is eliminated and the frequency change rate is reduced. The term corresponding to the additional frequency damping coefficient in the second expression is The corresponding terms cancel each other out, so that the frequency term can present positive damping, ensuring the stability of the system.

[0069] In one embodiment, the control model for synchronization between the new energy unit and the power grid is:

[0070]

[0071] in, is the reactive current command value of the new energy unit, ki is the phase-locked loop integral gain, is the phase-locked loop output frequency, is the active power command value of the new energy unit, P o is the active power detection value of the new energy unit, k p is the proportional gain of the phase-locked loop, V g is the voltage amplitude of the grid connection point of the new energy unit, ω g is the power grid frequency detection value, L g is the inductance between the new energy unit and the grid connection point, u od is the d-axis component of the phase-locked loop output voltage, R g is the resistance value between the new energy unit and the grid connection point, is the angle between the dq synchronous rotating coordinate system and the system common rotating coordinate system, is the deflection angle, .

[0072] The modeling process of the control model can be to first construct the relationship between the dq synchronous rotating coordinate system and the system common rotating coordinate system:

[0073]

[0074] Ignoring the faster current loop dynamics, the relationship between the output voltage of the new energy unit converter and the grid voltage is constructed:

[0075]

[0076] In this formula, and They are respectively the active current detection value and command value of the new energy unit, and are the reactive current detection value and command value of the new energy unit, u oq is the q-axis component of the phase-locked loop output voltage.

[0077] Furthermore, the phase-locked loop dynamically satisfies:

[0078]

[0079] Substituting the above two equations into this equation, the control model in this embodiment can be obtained.

[0080] The present application provides a transient control device for a new energy generator set, which is applied to a new energy generator set that is synchronized with a power grid through a phase-locked loop. The transient control device for the new energy generator set includes a judgment module, a first processing module, a second processing module and a sending module. The judgment module is used to judge whether the control conditions are met when entering the transient process. The first processing module is used to determine the initial command value according to the change rate of the phase-locked loop output frequency at the current moment and the previous moment, the reactive current command value at the current moment and the active power detection value at the current moment when the control conditions are met. The second processing module is used to adjust the initial command value according to the product of the difference between the phase-locked loop output frequency at the current moment and the power grid frequency detection value at the current moment and the additional frequency damping coefficient to obtain the final command value. The sending module is used to send the final command value as the active power command value to the new energy generator set.

[0081] For the specific limitations of the transient control device of the new energy unit, please refer to the limitations of the transient control method of the new energy unit above, which will not be repeated here. Each module in the above-mentioned transient control device of the new energy unit can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0082] The present application provides a computer device, including one or more processors and a memory, wherein computer-readable instructions are stored in the memory. When the computer-readable instructions are executed by the one or more processors, the following are performed: when entering a transient process, determine whether a control condition is met; if so, determine an initial command value based on a phase-locked loop output frequency change rate between a current moment and a previous moment, a reactive current command value at a current moment, and an active power detection value at a current moment; adjust the initial command value based on a difference between the phase-locked loop output frequency at a current moment and a grid frequency detection value at a current moment and the product of an additional frequency damping coefficient to obtain a final command value; and send the final command value as an active power command value to the new energy generator set.

[0083] In one embodiment, when the computer-readable instructions are executed by one or more processors, the steps of the method for transient control of a new energy generator set in any of the above embodiments are executed.

[0084] Indicatively, Figure 2 As shown, Figure 2 A schematic diagram of the internal structure of a computer device provided in an embodiment of the present application. Figure 2The computer device 200 includes a processing component 202, which further includes one or more processors, and a memory resource represented by a memory 201, for storing instructions executable by the processing component 202, such as an application. The application stored in the memory 201 may include one or more modules, each corresponding to a set of instructions. In addition, the processing component 202 is configured to execute instructions to perform the steps of the transient control method of the new energy unit in any of the above embodiments.

[0085] The computer device 200 may further include a power supply component 203 configured to perform power management of the computer device 200 , a wired or wireless network interface 204 configured to connect the computer device 200 to a network, and an input / output (I / O) interface 205 .

[0086] The present application provides a storage medium, in which computer-readable instructions are stored. When the computer-readable instructions are executed by one or more processors, the one or more processors execute: when entering a transient process, determine whether a control condition is met; if so, determine an initial command value based on the rate of change of a phase-locked loop output frequency between a current moment and a previous moment, a reactive current command value at a current moment, and an active power detection value at a current moment; adjust the initial command value based on the difference between the phase-locked loop output frequency at a current moment and the power grid frequency detection value at a current moment and the product of an additional frequency damping coefficient to obtain a final command value; and send the final command value as an active power command value to the new energy unit.

[0087] In one of the embodiments, the storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the transient control method of the new energy unit in any of the above embodiments.

[0088] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0089] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0090] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transient control method for a new energy unit, characterized in that: Applied to a new energy generator set that is synchronized with a power grid through a phase-locked loop, the transient control method of the new energy generator set includes: When entering the transient process, determine whether the control conditions are met; If yes, then determine the initial command value according to the phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment; The initial command value is adjusted according to the product of the difference between the phase-locked loop output frequency at the current moment and the power grid frequency detection value at the current moment and the additional frequency damping coefficient to obtain a final command value; The final command value is sent to the new energy generator set as an active power command value.

2. The transient control method of new energy units according to claim 1 is characterized in that: The initial command value is determined according to the phase-locked loop output frequency change rate between the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment, including: The phase-locked loop output frequency change rate at the current moment and the previous moment, the reactive current command value at the current moment, and the active power detection value at the current moment are input into a first expression to obtain the initial command value; the first expression is: in, is the initial instruction value, is the active power detection value at the current moment, is the reactive current command value at the current moment, k i is the phase-locked loop integral gain, are the phase-locked loop output frequencies at the current moment and the previous moment respectively, are the times corresponding to the current moment and the previous moment respectively, is the rate of change of the phase-locked loop output frequency between the current moment and the previous moment.

3. The transient control method of new energy units according to claim 2 is characterized in that: The step of adjusting the initial command value according to the product of the difference between the phase-locked loop output frequency at the current moment and the power grid frequency detection value at the current moment and the additional frequency damping coefficient to obtain the final command value comprises: The phase-locked loop output frequency at the current moment, the power grid frequency detection value at the current moment and the initial command value are input into a second expression to obtain the final command value; the second expression includes: in, is the final instruction value, is the power grid frequency detection value at the current moment, K d is the additional frequency damping coefficient; the additional frequency damping coefficient satisfies: Among them, k p is the phase-locked loop proportional gain, is the voltage amplitude of the grid connection point of the new energy unit at the current moment, L g is the inductance between the new energy unit and the grid connection point, R g is the resistance value between the new energy unit and the grid connection point, is the d-axis component of the phase-locked loop output voltage at the current moment.

4. The transient control method of new energy units according to claim 1 is characterized in that: The determining whether the control condition is met includes: Determine the depth of grid voltage drop; If the grid voltage drop depth is greater than a set threshold, it is determined that the control condition is met.

5. The transient control method of new energy units according to claim 4 is characterized in that: The set threshold is 50%.

6. The transient control method of new energy units according to claim 1 is characterized in that: The control model for synchronization between the new energy unit and the power grid is: in, is the reactive current command value of the new energy unit, k i is the phase-locked loop integral gain, is the phase-locked loop output frequency, is the active power command value of the new energy unit, P o is the active power detection value of the new energy unit, k p is the proportional gain of the phase-locked loop, V g is the voltage amplitude of the grid connection point of the new energy unit, ω g is the power grid frequency detection value, L g is the inductance between the new energy unit and the grid connection point, u od is the d-axis component of the phase-locked loop output voltage, R g is the resistance value between the new energy unit and the grid connection point, is the angle between the dq synchronous rotating coordinate system and the system common rotating coordinate system, is the deflection angle, .

7. The transient control method of new energy units according to claim 1 is characterized in that: The transient process includes a power grid short circuit fault.

8. A transient control device for a new energy unit, characterized in that: Applicable to a new energy generator set that is synchronized with a power grid through a phase-locked loop, the new energy generator set transient control device comprises: A judgment module is used to judge whether the control conditions are met when entering a transient process; A first processing module, configured to determine an initial command value according to a phase-locked loop output frequency change rate between a current moment and a previous moment, a reactive current command value at a current moment, and an active power detection value at a current moment when the control condition is met; A second processing module, used to adjust the initial command value according to the product of the difference between the phase-locked loop output frequency at the current moment and the power grid frequency detection value at the current moment and the additional frequency damping coefficient, so as to obtain a final command value; The sending module is used to send the final command value as the active power command value to the new energy unit.

9. A computer device, characterized in that: It includes one or more processors and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the transient control method of the new energy unit described in any one of claims 1-7 are executed.

10. A storage medium, characterized in that: The storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the transient control method for a new energy generator set as described in any one of claims 1-7.

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