Parallel converter low voltage ride through control method and device, electronic equipment and medium

Abstract

The invention relates to a parallel converter low-voltage ride-through control method and device, electronic equipment and a medium. Comprising the steps of calculating a power angle and an angular frequency of a synchronous generator during a power system fault period based on topological parameters of a power system and current output power of the synchronous generator; based on the power angle and the angular frequency during the power system fault period, calculating a rotor acceleration area of the synchronous generator during the power system fault period; and determining a target rotor deceleration area of the synchronous generator based on the rotor acceleration area, and controlling the converter to absorb the active power based on the target rotor deceleration area until the power angle of the synchronous generator is in a preset stable state after the power system fault is removed. Therefore, the converter is controlled to absorb the active power after the fault is removed according to the acceleration area information of the generator rotor at the moment of fault removal, the problem that the power angle stability of the generator is poor due to the low-voltage ride-through mode of the existing parallel converter is solved, and the stability and reliability of a power system are improved.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a method, device, electronic equipment and medium for controlling low voltage ride-through of a parallel converter. Background Art

[0002] In the power system, the low voltage ride-through technology of the grid-connected converter refers to the ability of the converter to maintain normal operation, not disconnect from the grid, and not interrupt the transmission of electric energy to the grid when the grid voltage drops briefly. It is a key technology to ensure that the power system can still operate stably under the condition of voltage drop.

[0003] In the related art, after the power system fault is cleared, since the converter near the generator is still in the low voltage ride-through mode, the parallel converter will gradually resume outputting the rated active power.

[0004] However, this method will affect the electromagnetic power output of the generator, resulting in poor power angle stability of the generator, which needs to be solved urgently. Summary of the invention

[0005] The present application provides a parallel converter low voltage ride-through control method, device, electronic device and medium to solve the problem of poor power angle stability of the generator caused by the low voltage ride-through method of the existing parallel converter, realize precise control of the power angle stability of the synchronous generator, and further improve the stability and reliability of the power system.

[0006] To achieve the above object, a first embodiment of the present application provides a low voltage ride through control method for parallel converters, comprising the following steps:

[0007] Acquire topological parameters of the power system and the current output power of the synchronous generator, and calculate the power angle and angular frequency of the synchronous generator during the power system fault based on the topological parameters and the current output power;

[0008] calculating a rotor acceleration area of ​​the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault;

[0009] A target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area, and the converter is controlled to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator is in a preset stable state after the power system fault is removed.

[0010] According to one embodiment of the present application, determining the target rotor deceleration area of ​​the synchronous generator based on the rotor acceleration area includes:

[0011] Determining whether the fault of the power system has been cleared;

[0012] In the case of fault removal in the power system, obtain the initial rotor deceleration area of the synchronous generator;

[0013] Determine whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area;

[0014] In the case where the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0015] According to an embodiment of the present application, the controlling the converter to absorb active power based on the target rotor deceleration area includes:

[0016] Based on the target rotor deceleration area and the initial rotor deceleration area, determine the increase in the rotor deceleration area;

[0017] Adjust the current state of the converter to a preset active power regulation mode, and based on the increase in the rotor deceleration area, use a droop control strategy with variable coefficients to control the converter to absorb active power.

[0018] According to an embodiment of the present application, the active power is:

[0019]

[0020] where P ref is the reference value of the active power of the converter, S 4 is the target rotor deceleration area, S 2 is the initial rotor deceleration area, δ u is the power angle corresponding to the unstable equilibrium point of the synchronous generator, δ S is the power angle corresponding to the stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f 0 is the power frequency, and a and b are both undetermined coefficients.

[0021] According to an embodiment of the present application, after the power angle of the synchronous generator is in the preset stable state after the power system fault is removed, it further includes:

[0022] Control the converter to switch from the preset active power regulation mode to the preset steady-state regulation mode.

[0023] According to the low-voltage ride-through control method for a parallel converter proposed in an embodiment of the present application, by analyzing the power system topology and the generator output power, the power angle and angular frequency of the generator during a fault can be calculated; using this data, the rotor acceleration area of the generator during the fault is determined, and the target rotor deceleration area is set accordingly; by controlling the converter to absorb active power, it is ensured that the generator can return to a preset stable state after the fault is cleared. Thus, by controlling the converter to absorb active power after the fault is cleared according to the acceleration area information of the generator rotor at the moment of fault clearing, the problem that the power angle stability of the generator is poor caused by the existing low-voltage ride-through method of the parallel converter is solved, the precise control of the power angle stability of the synchronous generator is realized, and the stability and reliability of the power system are further improved.

[0024] To achieve the above object, an embodiment of the second aspect of the present application proposes a low-voltage ride-through control device for a parallel converter, including:

[0025] A first calculation module, configured to obtain the topology parameters of the power system and the current output power of the synchronous generator, and calculate the power angle and angular frequency of the synchronous generator during a power system fault based on the topology parameters and the current output power;

[0026] A second calculation module, configured to calculate the rotor acceleration area of the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault;

[0027] A control module, configured to determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area, and control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator after the power system fault is cleared is in a preset stable state.

[0028] According to an embodiment of the present application, the control module is specifically configured to:

[0029] Judge whether the fault of the power system is cleared;

[0030] When the fault of the power system is cleared, obtain the initial rotor deceleration area of the synchronous generator;

[0031] Judge whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area;

[0032] When the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0033] According to an embodiment of the present application, the control module is specifically configured to:

[0034] Determine the increase in the rotor deceleration area based on the target rotor deceleration area and the initial rotor deceleration area;

[0035] Adjust the current state of the converter to a preset active power regulation mode, and based on the increase in the rotor deceleration area, use a droop control strategy with variable coefficients to control the converter to absorb active power.

[0036] According to an embodiment of the present application, the active power is:

[0037]

[0038] where P ref is the reference value of the active power of the converter, S 4 is the target rotor deceleration area, S 2 is the initial rotor deceleration area, δ u is the power angle corresponding to the unstable equilibrium point of the synchronous generator, δ S is the power angle corresponding to the stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f 0 is the power frequency, and a and b are both undetermined coefficients.

[0039] According to an embodiment of the present application, after the power angle of the synchronous generator is in the preset stable state after the power system fault is removed, the control module is further configured to:

[0040] Control the converter to switch from the preset active power regulation mode to the preset steady-state regulation mode.

[0041] According to the parallel converter low-voltage ride-through control device proposed in the embodiment of the present application, by analyzing the power system topology and the generator output power, the power angle and angular frequency of the generator during the fault can be calculated; using these data to determine the generator rotor acceleration area during the fault, and setting the target rotor deceleration area accordingly; by controlling the converter to absorb active power, it is ensured that the generator can return to the preset stable state after the fault is removed. Thus, by controlling the converter to absorb active power after the fault is removed according to the acceleration area information of the generator rotor at the moment of fault removal, the problem that the existing low-voltage ride-through method of the parallel converter causes poor power angle stability of the generator is solved, realizing precise control of the power angle stability of the synchronous generator, and further improving the stability and reliability of the power system.

[0042] To achieve the above object, an embodiment of the third aspect of the present application proposes an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the program to implement the parallel converter low-voltage ride-through control method as described in the above embodiment.

[0043] To achieve the above object, an embodiment of the fourth aspect of the present application provides a computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to implement the parallel converter low-voltage ride-through control method as described in the above embodiments.

[0044] To achieve the above object, an embodiment of the fifth aspect of the present application provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it is used to implement the parallel converter low-voltage ride-through control method as described in the above embodiments.

[0045] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where:

[0047] Figure 1 FIG. is a flowchart of a parallel converter low-voltage ride-through control method according to an embodiment of the present application;

[0048] Figure 2 FIG. is a schematic diagram of a low-voltage ride-through curve of an energy storage converter in the related art;

[0049] Figure 3 FIG. is a schematic diagram of the topology of a power system according to an embodiment of the present application;

[0050] Figure 4 FIG. is a schematic diagram of a power angle characteristic curve of a synchronous generator according to an embodiment of the present application;

[0051] Figure 5 FIG. is a block diagram of a parallel converter low-voltage ride-through control device according to an embodiment of the present application;

[0052] Figure 6 FIG. is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0054] The parallel converter low-voltage ride-through control method, device, electronic device and medium according to the embodiments of the present application will be described below with reference to the accompanying drawings.

[0055] Figure 1 It is a flowchart of the low-voltage ride-through control method for a parallel converter according to an embodiment of the present application.

[0056] Before introducing the low-voltage ride-through control method for the parallel converter proposed in the embodiments of the present application, the low-voltage ride-through method for grid-connected converters in the related art is introduced first.

[0057] As Figure 2 shown, in the power system, the converter can generate reactive current as needed under low voltage conditions. Reactive power means no energy conversion. After meeting the reactive power demand, the converter will also use the remaining capacity to provide active current, and active power means actual work. When a fault occurs in the power system, the electromagnetic power generated by the generator will decrease significantly, resulting in the acceleration of the generator rotor. After the fault is removed, although the electromagnetic power of the generator increases, since the deceleration area of the rotor is not enough to restore the rotor to the normal speed, if the power angle of the generator (i.e., the phase difference between the terminal voltage phase angle of the synchronous generator and the grid phase angle) exceeds the critical value of the unstable equilibrium point, the generator will lose synchronization, that is, fall out of step. After the fault is removed, if the converter near the generator is still in the low-voltage ride-through mode, that is, the converter gradually resumes to output the rated active power, this will further affect the electromagnetic power output of the generator, thus being unfavorable for the deceleration of the generator rotor and increasing the difficulty for the generator to resume stable operation.

[0058] Based on the above problems, the embodiments of the present application propose a new low-voltage ride-through control method for parallel converters. According to the acceleration area information of the generator rotor at the moment of fault removal, the converter is controlled to absorb active power after the fault is removed, thereby increasing the deceleration area of the generator rotor. Thus, the problem that the power angle stability of the generator is poor caused by the existing low-voltage ride-through method of parallel converters is solved, and the precise control of the power angle stability of the synchronous generator is realized, further improving the stability and reliability of the power system.

[0059] Exemplarily, as Figure 1 shown, the low-voltage ride-through control method for the parallel converter includes the following steps:

[0060] In step S101, the topological parameters of the power system and the current output power of the synchronous generator are obtained, and based on the topological parameters and the current output power, the power angle and angular frequency of the synchronous generator during the power system fault are calculated.

[0061] Among them, the topological parameters refer to the data describing the connection relationship and electrical characteristics of each device in the power system. The power angle refers to the phase difference between the terminal voltage phase angle of the synchronous generator and the grid phase angle during the operation of the synchronous generator. The angular frequency reflects the rotation speed of the synchronous generator rotor.

[0062] Specifically, the power system topology is as follows Figure 3 shown, including a synchronous generator (a device that can convert mechanical energy into AC electrical energy, characterized by a strict synchronous relationship between its rotational speed and the frequency of the generated AC power), a energy storage converter (i.e., a shunt converter) near the generator, which are connected to an infinite power grid through their respective line impedances. When a fault occurs in the power system is detected, since the angular frequency measurement of the synchronous generator mainly relies on physical sensors, and these sensors often have large errors, which leads to certain difficulties in capturing the frequency deviation during the transient process. To overcome this problem, the power angle and angular frequency of the synchronous generator during the power system fault can be accurately calculated based on the topology parameters of the power system and the current output power of the synchronous generator. These two parameters are crucial for evaluating the dynamic stability of the power system and preventing system collapse.

[0063] The calculation formula is as follows:

[0064]

[0065] where, δ is the power angle of the synchronous generator during the power system fault, f is the angular frequency of the synchronous generator during the power system fault, P e is the current output power of the synchronous generator, X is the equivalent line impedance, E is the output voltage of the synchronous generator, and V is the power grid voltage.

[0066] In step S102, based on the power angle and angular frequency of the synchronous generator during the power system fault, calculate the rotor acceleration area of the synchronous generator during the power system fault.

[0067] Among them, the rotor acceleration area is an index reflecting the change of the rotor kinetic energy of the synchronous generator, and it is closely related to the dynamic behavior of the synchronous generator during the fault.

[0068] Specifically, the power angle curve of the synchronous generator during the power fault can be as follows Figure 4 shown, where curve Ⅱ is the power angle curve when the power system is operating normally, and curve Ⅰ is the power angle curve after the power system fault. Next, based on the power angle and angular frequency of the synchronous generator during the power system fault, the rotor acceleration area of the synchronous generator during the fault (i.e., from the start time of the fault to the fault clearing time) can be calculated by real-time integration (such as the S Figure 4 area shown), until the fault clearing of the power system is detected. 1 area), until the fault clearing of the power system is detected.

[0069] That is, the rotor acceleration area of the synchronous generator during the power system fault is:[[]]

[0070]

[0071] Among them, S 1 is the rotor acceleration area of the synchronous generator during the power system fault, and δ c is the power angle of the synchronous generator when the fault is cleared, and δ s is the power angle of the synchronous generator during stable operation, and P real is the reference value of the active power of the synchronous generator.

[0072] In step S103, based on the rotor acceleration area, determine the target rotor deceleration area of the synchronous generator, and control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator after the power system fault is cleared is in a preset stable state.

[0073] Among them, the target rotor deceleration area refers to the kinetic energy area that the rotor of the synchronous generator needs to consume in order to enable the synchronous generator to quickly return to the stable operation state after the fault is cleared.

[0074] It can be understood that when the power system fault is cleared, if the near-area converter has no startup action, then the deceleration area of the synchronous generator (i.e., the initial rotor deceleration area) can be represented by Figure 4 the S in 2 area. In this case, if the area of the S 2 area is smaller than the area of the S 1 area, then the synchronous generator will experience an out-of-step phenomenon.

[0075] In order to effectively increase the deceleration area of the synchronous generator to prevent out-of-step from occurring, the embodiment of the present application can, after the power system fault is cleared, determine the target rotor deceleration area S 1 of the synchronous generator after the power system fault according to the calculated rotor acceleration area S 4 during the power system fault. To achieve this goal, the converter can be controlled to absorb the corresponding active power, thereby helping the synchronous generator to slow down its speed until the power angle of the synchronous generator after the power system fault is cleared reaches the preset stable state to ensure the safe and stable operation of the entire power system.

[0076] Next, a detailed description will be given on how to determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0077] As a possible implementation method, in some embodiments, the target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area, including: judging whether the fault of the power system is eliminated; when the fault of the power system is eliminated, obtaining the initial rotor deceleration area of ​​the synchronous generator; judging whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area; when the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determining the target rotor deceleration area of ​​the synchronous generator based on the rotor acceleration area.

[0078] Specifically, we can first determine whether the fault of the power system has been successfully removed. If the fault of the power system is confirmed to be removed, we can obtain the initial rotor deceleration area S of the synchronous generator at the time of fault removal. 2 Based on the rotor acceleration area S 1 and initial rotor deceleration area S 2 , can be further analyzed and calculated, that is, the rotor acceleration area S 1 and initial rotor deceleration area S 2 By comparison, if the rotor acceleration area S 1 Greater than or equal to the initial rotor deceleration area S 2 , then according to the rotor acceleration area S 1 Determine the target rotor deceleration area S of the synchronous generator 4 In order to prevent the occurrence of out-of-step, the target rotor deceleration area S of the synchronous generator is 4 Need to be greater than or equal to the rotor acceleration area S 1 .

[0079] Next, how to control the converter to absorb active power based on the target rotor deceleration area is described in detail.

[0080] As a possible implementation method, in some embodiments, the converter is controlled to absorb active power based on the target rotor deceleration area, including: determining the increase in the rotor deceleration area based on the target rotor deceleration area and the initial rotor deceleration area; adjusting the current state of the converter to convert it to a preset active regulation mode, and based on the increase in the rotor deceleration area, controlling the converter to absorb active power using a variable coefficient droop control strategy.

[0081] Specifically, in order to achieve the target rotor deceleration area S 4 Greater than or equal to the rotor acceleration area S 1 , can be based on the target rotor deceleration area S 4 and the initial rotor deceleration area S 2 , determine the increase in rotor deceleration area (i.e. S 4 -S 2) Subsequently, the current operating state of the converter is adjusted to switch it to the preset active power regulation mode. Using the droop control strategy with variable coefficients, the active power absorbed by the converter is controlled according to the increase in the rotor deceleration area to ensure the stable operation of the entire system.

[0082] To achieve this adjustment, the embodiment of the present application uses an adaptive expression to calculate the amount of active power that the converter should absorb. The expression is as follows:

[0083] P ref = g(f, δ s , δ, S 2 , S 4 ); (4)

[0084] Wherein, P ref is the reference value of the active power of the converter, that is, the active power that the converter should absorb.

[0085] Furthermore, the active power that the converter should absorb can also be expressed as:

[0086]

[0087] Wherein, when f = f 0 , δ = δ s , P ref = 0. When P ref is positive, it indicates that the converter absorbs active power. S 4 is the target rotor deceleration area, S 2 is the initial rotor deceleration area, δ u is the power angle corresponding to the unstable equilibrium point of the synchronous generator, δ S is the power angle corresponding to the stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f 0 is the power frequency, and a and b are both undetermined coefficients.

[0088] If P ref > P max , then let P ref = P max , wherein, P max is the maximum active power that the converter is allowed to absorb.

[0089] According to the reference value of the active power of the converter, the converter is adjusted. Under the action of the converter, the increase in the actual rotor deceleration area of the synchronous generator can be as shown in the S Figure 4 area of 3 . It should be noted that in this case, its equivalent power angle curve III does not necessarily exhibit the characteristics of a standard sine wave, but converges to the dynamic change curve of δ u . During this dynamic change process, S2 +S 3 The area represented by can still be calculated by the method of real-time integration, that is:

[0090]

[0091] The maximum deceleration area of the synchronous generator (i.e., the maximum target rotor deceleration area) can be expressed as:

[0092]

[0093] Theoretically, when the following expression is satisfied, the transient synchronous stability of the synchronous generator can be ensured, that is:

[0094] S 1 ≤ max(S 2 +S 3 ); (8)

[0095] However, in actual operation, when the formula (9) is satisfied, the transient synchronous stability of the synchronous generator can be ensured, that is:

[0096] S 1 ≤ S 2 +S 3 . (9)

[0097] Theoretically, the actual increase in the rotor deceleration area S 3 can be completely controlled by the capacity and power of the energy storage converter. This means that as long as the capacity of the energy storage converter is large enough, it is always possible to ensure that the synchronous generator remains in a synchronous stable state during the transient process by applying the above formula.

[0098] It should be noted that if the rotor acceleration area S 1 is less than the initial rotor deceleration area S 2 , then the converter can ensure that the synchronous generator remains in a synchronous stable state during the transient process according to the original low voltage ride-through mode, that is, after the fault is removed, the converter gradually resumes to output the rated active power.

[0099] Furthermore, in some embodiments, after the power angle of the synchronous generator is in a preset stable state after the power system fault is removed, it further includes: controlling the converter to switch from a preset active power regulation mode to a preset steady-state regulation mode.

[0100] That is to say, after the power angle of the synchronous generator reaches the preset stable state after the power system fault is cleared (i.e., satisfying Equation (9) or the power angle is restored to the stable equilibrium point), the parallel converter can be changed from the preset active power regulation mode to the preset steady-state regulation mode, that is, the parallel converter is switched from the preset active power regulation mode to the steady-state set value state, so as to ensure the rapid recovery and stable operation of the power system after the fault, and improve the stability and reliability of the entire power system.

[0101] According to the low-voltage ride-through control method of the parallel converter proposed in the embodiment of the present application, by analyzing the power system topology and the generator output power, the power angle and angular frequency of the generator during the fault can be calculated; using these data to determine the rotor acceleration area of the generator during the fault, and setting the target rotor deceleration area accordingly; by controlling the converter to absorb active power, it is ensured that the generator can return to the preset stable state after the fault is cleared. Thus, by controlling the converter to absorb active power after the fault is cleared according to the acceleration area information of the generator rotor at the moment of fault clearing, the problem that the power angle stability of the generator is poor caused by the existing low-voltage ride-through method of the parallel converter is solved, and the precise control of the power angle stability of the synchronous generator is realized, further improving the stability and reliability of the power system.

[0102] Next, the low-voltage ride-through control device of the parallel converter proposed in the embodiment of the present application will be described with reference to the drawings.

[0103] Figure 5 It is a block diagram of the low-voltage ride-through control device of the parallel converter according to an embodiment of the present application.

[0104] As Figure 5 shown, the low-voltage ride-through control device 10 of the parallel converter includes: a first calculation module 100, a second calculation module 200, and a control module 300.

[0105] Among them, the first calculation module 100 is used to obtain the topology parameters of the power system and the current output power of the synchronous generator, and calculate the power angle and angular frequency of the synchronous generator during the power system fault based on the topology parameters and the current output power;

[0106] The second calculation module 200 is used to calculate the rotor acceleration area of the synchronous generator during the power system fault based on the power angle and angular frequency of the synchronous generator during the power system fault;

[0107] The control module 300 is used to determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area, and control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator after the power system fault is cleared is in the preset stable state.

[0108] Further, in some embodiments, the control module 300 is specifically configured to:

[0109] Determine whether the fault of the power system is cleared;

[0110] When the fault of the power system is cleared, obtain the initial rotor deceleration area of the synchronous generator;

[0111] Determine whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area;

[0112] When the rotor acceleration area is greater than or equal to the initial rotor deceleration area, determine the target rotor deceleration area of the synchronous generator based on the rotor acceleration area.

[0113] Further, in some embodiments, the control module 300 is specifically configured to:

[0114] Determine the increase amount of the rotor deceleration area based on the target rotor deceleration area and the initial rotor deceleration area;

[0115] Adjust the current state of the converter to a preset active power regulation mode, and control the converter to absorb active power by using a droop control strategy with variable coefficients based on the increase amount of the rotor deceleration area.

[0116] Further, in some embodiments, the active power is:

[0117]

[0118] Wherein, P ref is the reference value of the active power of the converter, S 4 is the target rotor deceleration area, S 2 is the initial rotor deceleration area, δ u is the power angle corresponding to the unstable equilibrium point of the synchronous generator, δ S is the power angle corresponding to the stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f 0 is the power frequency, and a and b are undetermined coefficients.

[0119] Further, in some embodiments, after the power angle of the synchronous generator is in a preset stable state after the power system fault is cleared, the control module 300 is further configured to:

[0120] Control the converter to convert from the preset active power regulation mode to the preset steady-state regulation mode.

[0121] It should be noted that the foregoing explanation of the embodiments of the low-voltage ride-through control method for the parallel converter is also applicable to the low-voltage ride-through control device of the parallel converter in this embodiment, and will not be elaborated here.

[0122] The low-voltage ride-through control device for a parallel converter proposed according to an embodiment of the present application can calculate the power angle and angular frequency of a generator during a fault by analyzing the power system topology and the generator output power; determine the accelerating area of the generator rotor during the fault using this data, and set a target decelerating area accordingly; and ensure that the generator can return to a preset stable state after the fault is cleared by controlling the converter to absorb active power. Thus, by controlling the converter to absorb active power after the fault is cleared based on the accelerating area information of the generator rotor at the moment of fault clearing, the problem that the power angle stability of the generator is poor caused by the existing low-voltage ride-through method of the parallel converter is solved, precise control of the power angle stability of the synchronous generator is achieved, and the stability and reliability of the power system are further improved.

[0123] Figure 6 The structural schematic diagram of the electronic device provided by the embodiment of the present application. The electronic device may include:

[0124] A memory 601, a processor 602, and a computer program stored on the memory 601 and executable on the processor 602.

[0125] When the processor 602 executes the program, it implements the low-voltage ride-through control method for the parallel converter provided in the above embodiment.

[0126] Furthermore, the electronic device further includes:

[0127] A communication interface 603 for communication between the memory 601 and the processor 602.

[0128] The memory 601 is used to store a computer program executable on the processor 602.

[0129] The memory 601 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0130] If the memory 601, the processor 602, and the communication interface 603 are implemented independently, the communication interface 603, the memory 601, and the processor 602 may be interconnected through a bus and communicate with each other. The bus may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6It is represented by only one thick line, but it does not mean that there is only one bus or one type of bus.

[0131] Optionally, in a specific implementation, if the memory 601, the processor 602, and the communication interface 603 are integrated on a single chip, the memory 601, the processor 602, and the communication interface 603 can communicate with each other through an internal interface.

[0132] The processor 602 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0133] The embodiments of the present application further provide a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the low-voltage ride-through control method of the parallel converter as described above is implemented.

[0134] The embodiments of the present application further provide a computer program product, which includes a computer program, and when the computer program is executed by a processor, the low-voltage ride-through control method of the parallel converter as described above is implemented.

[0135] In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0136] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0137] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A low voltage ride through control method for parallel converters, characterized in that: The following steps are involved: Acquire topological parameters of the power system and the current output power of the synchronous generator, and calculate the power angle and angular frequency of the synchronous generator during the power system fault based on the topological parameters and the current output power; calculating a rotor acceleration area of ​​the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault; A target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area, and the converter is controlled to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator is in a preset stable state after the power system fault is removed.

2. The method according to claim 1, characterized in that The determining a target rotor deceleration area of ​​the synchronous generator based on the rotor acceleration area comprises: Determining whether the fault of the power system has been cleared; In case of fault removal of the power system, obtaining an initial rotor deceleration area of ​​the synchronous generator; Determining whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area; In a case where the rotor acceleration area is greater than or equal to the initial rotor deceleration area, a target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area.

3. The method according to claim 2, characterized in that The step of controlling the converter to absorb active power based on the target rotor deceleration area includes: determining an increase in rotor deceleration area based on the target rotor deceleration area and the initial rotor deceleration area; The current state of the converter is regulated to be converted into a preset active power regulation mode, and based on the increase in the rotor deceleration area, a variable coefficient droop control strategy is used to control the converter to absorb active power.

4. The method according to claim 3, characterized in that The active power is: Among them, P ref is the reference value of the converter active power, S4 is the target rotor deceleration area, S2 is the initial rotor deceleration area, δ u is the power angle corresponding to the unstable equilibrium point of the synchronous generator, δ S is the power angle corresponding to the stable equilibrium point of the synchronous generator, f is the frequency of the synchronous generator, f0 is the power frequency, and a and b are both unknown coefficients.

5. The method according to claim 1, characterized in that: After the power angle of the synchronous generator is in the preset stable state after the fault of the power system is removed, the method further includes: The converter is controlled to switch from a preset active power regulation mode to a preset steady-state regulation mode.

6. A low voltage ride through control device for parallel converters, characterized in that: include: A first calculation module, used for obtaining topological parameters of the power system and the current output power of the synchronous generator, and calculating the power angle and angular frequency of the synchronous generator during a power system fault based on the topological parameters and the current output power; A second calculation module, configured to calculate a rotor acceleration area of ​​the synchronous generator during the power system fault based on the power angle and the angular frequency of the synchronous generator during the power system fault; A control module is used to determine a target rotor deceleration area of ​​the synchronous generator based on the rotor acceleration area, and control the converter to absorb active power based on the target rotor deceleration area until the power angle of the synchronous generator is in a preset stable state after the power system fault is removed.

7. The device according to claim 6, characterized in that The control module is specifically used for: Determining whether the fault of the power system has been cleared; In case of fault removal of the power system, obtaining an initial rotor deceleration area of ​​the synchronous generator; Determining whether the rotor acceleration area is greater than or equal to the initial rotor deceleration area; In a case where the rotor acceleration area is greater than or equal to the initial rotor deceleration area, a target rotor deceleration area of ​​the synchronous generator is determined based on the rotor acceleration area.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the low voltage ride-through control method for a parallel converter as described in any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the low voltage ride-through control method for parallel converters as described in any one of claims 1 to 5.

10. A computer program product, characterized in that It comprises a computer program, which, when executed by a processor, is used to implement the low voltage ride-through control method for parallel converters according to any one of claims 1 to 5.

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