Method and apparatus for controlling increase of active power of grid-forming converter, device, and medium

Abstract

The present application relates to the technical field of electrical control, and provides a method and apparatus for controlling increase of active power of a grid-forming converter, a device, and a medium. The method for controlling increase of active power of a grid-forming converter comprises: when a fault occurs in a power grid, determining an active power limiting curve on the basis of power angle stability limit parameters and converter alternating-current port data in the power grid; determining a second active power limiting value on the basis of the converter alternating-current port data and preset alternating-current overload threshold parameters; determining a third active power limiting value on the basis of battery charging and discharging parameters measured in real time; and determining limited equivalent mechanical power of a grid-forming converter for the power grid on the basis of the active power limiting curve, the second active power limiting value and the third active power limiting value. On the basis of limited equivalent mechanical power determined by analysis from the perspective of power angle stability, the perspective of ensuring that an alternating-current overload does not occur, and the perspective of battery charging and discharging, the present application can maximize increase of active power while avoiding power angle instability.

Description

Network-constructed converter active power increasing control method and device, equipment and medium TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical control, for example, to a network-constructed converter active power increasing control method, device, equipment and medium. BACKGROUND

[0002] With the development of social economy and technology, the proportion of new energy and power electronic equipment accessing the power grid is increasing. The characteristics of new energy and power electronic equipment have led to a decrease in the inertia of the power system, a weakening of the system strength, and a worsening of the stability problem. Network-constructed control technology simulates the characteristics of synchronous generators, making the converter appear as a voltage source, providing voltage and frequency support, and providing virtual inertia for the power system to compensate for the stability problem caused by the lack of inertia of new energy equipment. However, since it simulates the operation mechanism of synchronous machines, the network-constructed converter inevitably has a power angle stability problem. When the AC port voltage drops, if the active power of the converter is too large, it may exceed the static stability limit of the synchronous machine, easily leading to instability and oscillation. The deeper the AC voltage drop or the larger the active power, the more likely the converter is to lose stability. On the other hand, the power grid in remote areas is relatively weak, and when a fault occurs, the frequency often fluctuates dramatically. At this time, the network-constructed converter needs to provide active power during the fault to support the frequency. Therefore, how to ensure that the network-constructed energy storage neither loses power angle stability nor maximizes the active power during the fault is a problem that needs to be solved.

[0003] In related technologies, in order to ensure power angle stability, the active power of the network-constructed converter during the fault is usually greatly limited, which greatly reduces the frequency support capability of the network-constructed converter during the fault. Some power systems only consider that the output current of the converter does not exceed the maximum capacity limit. Therefore, the current network-constructed converter active power increasing control method causes power angle instability when maximizing the active power, and it is difficult to maximize the active power when the power angle is stable, and the overall control precision is low. SUMMARY

[0004] The present application aims to provide a network-constructed converter active power increasing control method, device, equipment and medium.

[0005] According to an aspect of the present application, a method for controlling active power increase of a grid-forming converter is provided, comprising: determining an active power limiting curve for the grid according to a power angle stability limit parameter and AC port data of the converter in the case of grid failure; determining a second active power limiting value for the grid according to the AC port data of the converter and a preset AC current overload threshold parameter; determining a third active power limiting value for the grid according to real-time measured battery charging and discharging parameters; and determining a limiting equivalent mechanical power of the grid-forming converter under grid voltage according to the active power limiting curve, the second active power limiting value and the third active power limiting value.

[0006] According to some embodiments, the first active power limiting value under different grid voltages is determined according to a preset power angle equation, a power angle stability limit parameter and AC port data of the converter, comprising: determining a static stability limit coefficient according to the power angle stability limit parameter; determining an AC port voltage according to the AC port data of the converter; determining a limiting value corresponding to the power angle equation according to the static stability limit coefficient and the AC port voltage; and determining the limiting value as the first active power limiting value corresponding to the AC port voltage.

[0007] According to some embodiments, the third active power limiting value for the grid is determined according to real-time measured battery charging and discharging parameters, comprising: determining a real-time operation limit value and a battery voltage according to the battery charging and discharging parameters; determining an upper limit of the third active power limiting value and a lower limit of the third active power limiting value based on the real-time operation limit value, the battery voltage, a real-time calculated conversion efficiency of the converter and a preset rated active power of the converter; and determining the upper limit of the third active power limiting value and the lower limit of the third active power limiting value as the third active power limiting value.

[0008] According to some embodiments, the limiting equivalent mechanical power of the grid-forming converter under the grid voltage is determined according to the active power limiting curve, the second active power limiting value and the third active power limiting value, comprising: determining a minimum active power limiting value under the grid voltage according to the active power limiting curve, the second active power limiting value and the third active power limiting value; determining an upper limit of the equivalent mechanical power and a lower limit of the equivalent mechanical power according to a preset equivalent mechanical power determination mode and the minimum active power limiting value; determining a virtual inertia limiting mode of the current equivalent mechanical power according to a preset active power reference data; and determining the limiting equivalent mechanical power of the grid-forming converter under the grid voltage according to the upper limit of the equivalent mechanical power, the lower limit of the equivalent mechanical power, the virtual inertia limiting mode and the grid voltage.

[0009] According to an aspect of the present application, a device for controlling active power increase of a grid-forming converter is provided, comprising:

[0010] The amplitude limiting curve determination module is configured to determine an active power amplitude limiting curve for the power grid according to the power angle stability limit parameter and the AC port data of the converter in the case of a power grid fault;

[0011] The overload amplitude value determination module is configured to determine a second active power amplitude value for the power grid according to the AC port data of the converter and a preset AC current overload threshold parameter.

[0012] The battery amplitude value determination module is configured to determine a third active power amplitude value for the power grid according to the real-time measured battery charging and discharging parameter.

[0013] The equivalent mechanical power determination module is configured to determine a limiting equivalent mechanical power of the grid-connected converter under the grid voltage for the power grid according to the active power amplitude limiting curve, the second active power amplitude value and the third active power amplitude value.

[0014] According to an aspect of the present application, an electronic device is provided, which includes a processor, a memory storing a computer program, when the computer program is executed by the processor, the processor executes the grid-connected converter active power output control method as described above.

[0015] According to an aspect of the present application, a non-transitory computer readable medium is provided, which stores readable instructions, when the instructions are executed by the processor, the processor executes the grid-connected converter active power output control method as described above.

[0016] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. Advantages:

[0017] Through the above embodiments provided by the present application, the corresponding active power amplitude limiting curve, the second active power amplitude value and the third active power amplitude value are determined from the perspective of power angle stability, the perspective of ensuring that the AC current is not overloaded and the perspective of battery charging and discharging, which enhances the stability of the power grid in the fault state and ensures that the converter can operate safely and stably during the power grid fault. At the same time, the actual operating conditions of the energy storage battery are considered, which helps to reasonably dispatch the energy storage resources when the power grid fails, and ensures the safe operation of the battery. The active power amplitude limiting curve, the second active power amplitude value and the third active power amplitude value are comprehensively considered, which can accurately calculate the limiting equivalent mechanical power of the grid-connected converter under the grid voltage, and can maximize the output of active power while avoiding power angle instability, AC current overload and battery current overload. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art according to these drawings without departing from the scope of the present application.

[0019] Fig. 1 is a flow chart of the method for controlling the active power increase of the grid-connected converter according to an embodiment of the present application;

[0020] Fig. 2 is a flow chart of the implementation steps of step S10 according to an embodiment of the present application;

[0021] Fig. 3 is a flow chart of the implementation steps of step S101 according to an embodiment of the present application;

[0022] Fig. 4 is a schematic diagram of the power angle curve before and after voltage sag according to an embodiment of the present application;

[0023] Fig. 5 is a schematic diagram of the curve function of the static stability limit coefficient according to an embodiment of the present application;

[0024] Fig. 6 is a flow chart of the implementation steps of step S11 according to an embodiment of the present application;

[0025] Fig. 7 is a flow chart of the implementation steps of step S12 according to an embodiment of the present application;

[0026] Fig. 8 is a flow chart of the implementation steps of step S13 according to an embodiment of the present application;

[0027] Fig. 9 is a block diagram of the device for controlling the active power increase of the grid-connected converter according to an embodiment of the present application;

[0028] Fig. 10 is a schematic diagram of the structure of the electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments may, however, be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the figures, and descriptions of the same elements will not be repeated.

[0030] The specific implementation can refer to the following embodiments.

[0031] FIG. 1 is a flowchart of a method for active power control of a grid-forming converter according to an embodiment of the present application. The method can be applied to a controller corresponding to the grid-forming converter used in the present application. As shown in FIG. 1, the method includes steps S10, S11, S12, and S13.

[0032] In step S10, in the case of a power grid failure, an active power limiting curve for the power grid is determined according to a power angle stability limit parameter and converter AC port data in the power grid.

[0033] The power angle stability limit parameter can be used to represent parameters related to power angle stability in the power grid, and can include internal potential amplitude, impedance angle, and voltage drop depth of the grid-forming converter. The converter AC port data can be used to represent relevant data of the AC port of the grid-forming converter for the power grid, and can include AC port voltage, voltage starting value of the limiting curve, etc.

[0034] According to an example embodiment, in the case of a power grid failure, the active power limiting curves corresponding to different power angle stability limit parameters and converter AC port data can be pre-set and stored. The active power limiting curve corresponding to the current power angle stability limit parameter and converter AC port data is found.

[0035] In step S11, a second active power limiting value for the power grid is determined according to the converter AC port data and a pre-set AC current overload threshold parameter.

[0036] The pre-set AC current overload threshold parameter can be used to represent relevant parameters for ensuring that the AC current is not overloaded, and can include transient maximum overload multiple of the grid-forming converter, overload protection response time, etc. The second active power limiting value is used to represent the active power limiting value obtained from the perspective of ensuring that the AC current is not overloaded. The active power limiting value can be a set upper power limit. When the actual output power of a device or system approaches or exceeds this limit, certain measures (such as reducing the output power) are taken to prevent exceeding this limit.

[0037] According to an example embodiment, the second active power limiting values corresponding to different converter AC port data and AC current overload threshold parameters can be pre-set according to a number of historical data and stored. The second active power limiting value corresponding to the converter AC port data and the AC current overload threshold parameter at the current time is directly found.

[0038] In step S12, a third active power limiting value for the power grid is determined according to real-time measured battery charging and discharging parameters.

[0039] The battery charging and discharging parameter can include a real-time measured current limit value or a real-time measured power limit value, i.e., a real-time current limit value or a real-time power limit value. The third active power limit value can be used to represent the obtained active power limit value from the perspective of current charging and discharging.

[0040] According to an example embodiment, the third active power limit value corresponding to different battery charging and discharging parameters can be set in advance according to a number of historical data and stored. Then the third active power limit value corresponding to the battery charging and discharging parameter at the current time can be directly found.

[0041] In some implementations, the model can be enabled to output the active power limit curve, the second active power limit value, and the third active power limit value respectively by means of pre-establishing the model.

[0042] In step S13, the limit equivalent mechanical power of the grid-forming converter under the grid voltage for the grid is determined according to the active power limit curve, the second active power limit value, and the third active power limit value.

[0043] The grid-forming converter for the above-mentioned grid can indirectly affect the output of electromagnetic power by controlling the mechanical power of the virtual synchronous machine. The limit equivalent mechanical power is the corresponding electromagnetic power output after the grid-forming converter active power control.

[0044] According to some embodiments, the mechanical power output determination model can be trained according to historical grid-forming converter active power control data. The active power limit curve, the second active power limit value, the third active power limit value, and the grid voltage at the current time are input into the mechanical power output determination model, and the limit equivalent mechanical power of the grid-forming converter under the grid voltage is output.

[0045] The present application determines the corresponding active power limit curve, the second active power limit value, and the third active power limit value from the perspective of power angle stability, the perspective of ensuring that the alternating current is not overloaded, and the perspective of battery charging and discharging, respectively, enhances the stability of the grid in the fault state, and ensures that the converter can operate safely and stably during the grid fault. At the same time, the actual operating conditions of the energy storage battery are considered, which helps to reasonably dispatch the energy storage resources when the grid fails, and ensures the safe operation of the battery. The active power limit curve, the second active power limit value, and the third active power limit value are combined to accurately calculate the limit equivalent mechanical power of the grid-forming converter under the grid voltage, which can maximize the active power output while avoiding power angle instability, alternating current overload, and battery current overload.

[0046] According to some embodiments, with reference to FIG. 2, step S10 can be implemented by steps S100, S101, and S102.

[0047] In step S100, in the case of power grid failure, the power angle stability limit parameter and the converter AC port data in the power grid are acquired.

[0048] In the present application, the power angle stability limit parameter and the converter AC port data can be detected by the network construction converter in the present application.

[0049] According to an example embodiment, in the case of power grid failure, the controller can acquire the power angle stability limit parameter and the converter AC port data collected by the network construction converter.

[0050] In step S101, according to the preset power angle equation, the power angle stability limit parameter and the converter AC port data, the first active power limiting value under different power grid voltages is determined.

[0051] In the present application, the preset power angle equation can be set in advance according to the applied power grid scene and the demand of the manager for active power control. By acquiring the power angle stability limit parameter in real time, the stability margin of the power grid under the current state can be accurately evaluated. Combined with the converter AC port data, the active power output can be adjusted more finely.

[0052] According to an example embodiment, different power grid voltages, power angle stability limit parameters and converter AC port data can be substituted into the preset power angle equation for calculation to obtain the corresponding first active power limiting value under different power grid voltages.

[0053] In step S102, based on the first active power limiting value under different power grid voltages, the active power limiting curve is determined.

[0054] According to an example embodiment, the active power limiting curve can be generated by establishing a coordinate system with the power grid voltage as the horizontal coordinate and the first active power limiting value as the vertical coordinate.

[0055] Through the power angle stability limit parameter and the converter AC port data, the present application can ensure that the power grid still maintains high stability under fault conditions, effectively preventing system collapse caused by power angle instability. Based on the preset power angle equation and real-time data, the first active power limiting value under different power grid voltages is determined, which can realize dynamic optimization and distribution of active power. During power grid failure, by determining and applying the active power limiting curve, the output power of the converter can be effectively controlled to prevent equipment damage caused by overcurrent.

[0056] According to some embodiments, referring to FIG. 3, step S101 can be implemented through step S1010 and step S1011.

[0057] In step S1010, a static stability limit coefficient is determined according to the power angle stability limit parameter; and an AC port voltage is determined according to the converter AC port data.

[0058] In the present application, the power angle stability limit parameter includes the static stability limit coefficient, and the converter AC port data includes the AC port voltage.

[0059] According to the example embodiment, the static stability limit coefficient can be extracted from the power angle stability limit parameter, and the AC port voltage can be extracted from the converter AC port data.

[0060] In step S1011, a clipping value corresponding to the power angle equation is determined according to the static stability limit coefficient and the AC port voltage; and the clipping value is determined as a first active power clipping value corresponding to the AC port voltage.

[0061] In the present application, the use and calculation method of the parameters in the power angle equation can be pre-set according to the actual power grid application scenario and the demand of the management personnel for active power control.

[0062] According to the example embodiment, the power angle curve before and after the voltage drop is shown in FIG. 4. Wherein, P max is the static stability limit power point before the voltage drop, P' max is the static stability limit power point after the voltage drop, P set_a is the active power set value at the operating point a, P set_b is the active power set value at the operating point b, and δ is used to represent the power angle of different operating points, wherein, δ a is the power angle of the operating point a, and δ b is the power angle of the operating point b.

[0063] When the converter operating point is located at the point a, if the voltage drop occurs, the power angle curve will be lowered at this time. Since the power angle cannot be abruptly changed, the operating point will move to the point a', at this time, in order to meet the active power output reaching the original set value, the operating point will move to 90° along the new power angle curve. Since the maximum value P' max of the new power angle curve is still less than P set_a , the active power set value cannot be reached all the time, and will continue to move to 180° beyond 90°. According to the synchronous machine power angle stability principle, when the power angle exceeds 90°, the converter will be unstable.

[0064] When the converter operating point is located at the point b, if the voltage drop occurs, the power angle curve will be lowered at this time. Since the power angle cannot be abruptly changed, the operating point will move to the point b', at this time, in order to meet the active power output reaching the original set value P set_b , the operating point will move to 90° along the new power angle curve. When the power angle reaches b'2, the output active power reaches the set value Pset_b At this time, the converter will be stable at the operating point b'2. For this purpose, the active power limit module 1 is used to limit the power set value.

[0065] The power angle equation can be set as:

[0066] wherein P L1 is the limit value, i.e., the first active power limit value; U0 is the AC port voltage; K is a static stability limit coefficient, which is related to the drop depth of U0; E is the internal potential amplitude of the grid-forming converter; X is the sum of the virtual impedance of the grid-forming converter and the actual AC filter inductance impedance; is the impedance angle. In some implementations, E, X, may be preset into the power angle equation according to the actual parameters at the calculation time, and then the static stability limit coefficient and the AC port voltage obtained can be substituted to calculate the corresponding limit value, and the limit value is taken as the first active power limit value corresponding to the AC port voltage.

[0067] According to some embodiments, the curve function of K is set as:

[0068] wherein K U1 is the curve slope, is the maximum value of the limit curve, which can be selected to be greater than or equal to 0 to less than or equal to 1. U1 is the voltage starting per unit value of the limit curve, which can be selected to be greater than or equal to 0 to less than or equal to 0.9. A curve function of K can refer to FIG. 5, as shown in FIG. 5, U1 = 0.1 pu, K U1 = 1. The present application can use the K shown in FIG. 5 for calculation, which is more intuitive for the management personnel.

[0069] The present application determines the static stability limit coefficient according to the power angle stability limit parameter, and determines the first active power limit value under different grid voltages in combination with the converter AC port data, effectively controls the active power in the grid, and thus improves the overall stability of the grid. By dynamically adjusting the limit value of the active power according to the change of the grid voltage, the method enhances the adaptability of the grid to different operating conditions, so that the grid can maintain stable operation under a wider range of operating conditions.

[0070] According to some embodiments, whether the grid has a fault can be determined based on the converter AC port data. Specifically, the converter AC port voltage per unit value can be determined according to the converter AC port data; and whether the grid has a fault can be determined according to the converter AC port voltage per unit value.

[0071] The voltage unit of the AC port of the converter is used to represent the ratio of the actual voltage of the AC port of the converter to the preset reference voltage. By calculating the unit, comparison and analysis can be conveniently carried out under different voltage levels, and the running state of the power grid can be evaluated.

[0072] According to an example embodiment, the voltage unit of the AC port of the converter can be included in the data of the AC port of the converter and can be directly obtained when used. A fault threshold range can be preset, which is generally determined according to the stable running conditions of the power grid, historical data analysis and expert experience. The voltage unit of the AC port of the converter is matched with the preset fault threshold range, and if it is not within the preset fault threshold range, it can be determined that the power grid has a fault.

[0073] In some implementations, whether the power grid is in a fault state or a non-fault state corresponding to different voltage units of the AC port of the converter can be set according to a large amount of historical control data of active power generation of the network-constructed converter. A reference voltage value can be set according to the rated voltage of the power grid or specific analysis requirements. The reference voltage is usually the same as or proportional to the rated voltage. The ratio of the voltage of the AC port to the reference voltage value is calculated as the voltage unit of the AC port of the converter. Then, whether the power grid has a fault can be found corresponding to the voltage unit of the AC port of the converter.

[0074] The present application can accurately compare the preset reference value by obtaining the data of the AC port of the converter in real time and determining the voltage unit thereof, so as to more accurately determine whether the power grid has a fault. This method reduces the misjudgment caused by data fluctuations or errors and improves the accuracy of fault detection. Using the voltage unit for judgment avoids complex calculation and analysis process. The running personnel only needs to pay attention to whether the voltage unit exceeds the preset range, so as to quickly determine the state of the power grid, greatly simplifying the process of fault analysis and improving the work efficiency.

[0075] According to some embodiments, with reference to FIG. 6, step S11 can be implemented by step S110 and step S111.

[0076] In step S110, the maximum transient overload multiple of the converter is determined according to the preset AC current overload threshold parameter.

[0077] The AC current overload threshold parameter can include the maximum transient overload multiple of the converter, which can be used to represent the maximum current multiple that the network-constructed converter can withstand in the transient process (such as short circuit, overcurrent and other sudden situations).

[0078] According to an example embodiment, the maximum transient overload multiple of the converter can be extracted from the AC current overload threshold parameter.

[0079] In some implementations, the converter transient maximum overload multiple can also be set according to the properties of the networked converter, and the application can select 1.5 times or 3 times.

[0080] In step S111, a second active power limiting value is determined according to the AC port voltage in the converter AC port data and the converter transient maximum overload multiple.

[0081] According to the example embodiment, the converter AC port voltage reference value pre-set and stored can be found based on the AC port voltage in the converter AC port data. The smaller value between the converter AC port voltage reference value and the natural number 1 is selected, and then multiplied by the converter transient maximum overload multiple to obtain the second active power limiting value.

[0082] The application dynamically determines the second active power limiting value according to the converter AC port data and the AC current overload threshold parameter, effectively limits the active power output of the converter during the transient process, thereby preventing power fluctuations or failures caused by overload and improving the overall stability of the power grid. By setting a reasonable active power limiting value, it is ensured that the converter will not exceed its maximum carrying capacity during the transient process, thereby avoiding damage to the equipment due to overload and prolonging the service life of the converter.

[0083] According to some embodiments, with reference to FIG. 7, step S12 can be implemented by steps S120 and S121.

[0084] In step S120, a real-time operation limiting value and a battery voltage are determined according to the battery charging and discharging parameters.

[0085] In the application, the battery charging and discharging parameters can include a real-time operation limiting value and a battery voltage. The real-time operation limiting value refers to an instantaneous parameter threshold set during the operation of a specific power system or power equipment to ensure safe, stable and efficient operation. These limiting values are usually closely related to factors such as system performance, safety, equipment life and operating efficiency.

[0086] According to the example embodiment, the real-time operation limiting value and the battery voltage can be directly obtained from the battery charging and discharging parameters.

[0087] In step S121, a third active power limiting value upper limit and a third active power limiting value lower limit are determined based on the real-time operation limiting value, the battery voltage, the real-time calculated converter conversion efficiency and the pre-set converter rated active power, so as to determine the third active power limiting value upper limit and the third active power limiting value lower limit as the third active power limiting value.

[0088] The converter conversion efficiency refers to the ratio of the output power to the input power when the converter converts one form of electrical energy into another form. It is one of the key indicators for measuring the performance of the converter. The converter rated active power refers to the active power value that the converter can stably output for a long time under the rated working condition.

[0089] The converter conversion efficiency is a real-time calculated parameter. In some implementations, the battery voltage, the battery current, the converter output power and the converter rated power can be calculated according to a pre-set and stored calculation method to obtain the preset converter conversion efficiency. The preset converter rated active power can be a pre-set parameter.

[0090] According to an example embodiment, the following formula can be used:

[0091] wherein, P L3_dischrg represents the third active power amplitude value upper limit, P L3_chrg represents the third active power amplitude value lower limit. U bat represents the battery voltage, η represents the current converter conversion efficiency, P N represents the converter rated active power. The real-time running limit value can include a real-time discharge current limit value I dischrg , a real-time discharge power limit value P dischrg , a real-time charging current limit value I chrg and a real-time charging power limit value P chrg . The real-time running limit value, the battery voltage, the converter conversion efficiency and the converter rated active power are calculated according to the above formula to obtain the third active power amplitude value upper limit and the third active power amplitude value lower limit, respectively, and the third active power amplitude value upper limit and the third active power amplitude value lower limit are determined as the third active power amplitude value as a whole.

[0092] The application determines the third active power amplitude value in real time according to the battery charging and discharging parameters. The system can dynamically adjust its running power range to ensure that the battery works under safe charging and discharging conditions and avoid overheating, damage and even safety accidents caused by excessive power. The battery voltage, the converter conversion efficiency and the converter rated active power are combined for calculation to accurately control the output power of the converter, make it run in the optimal efficiency interval, reduce the loss in the energy conversion process and improve the overall energy utilization efficiency.

[0093] According to some embodiments, with reference to FIG. 8, step S13 can be implemented through steps S130, S131, S132 and S133.

[0094] In step S130, the active power minimum limiting value under the grid voltage is determined according to the active power limiting curve, the second active power limiting value and the third active power limiting value.

[0095] According to the example embodiment, the third active power limiting value upper limit and the third active power limiting value lower limit corresponding to the same grid voltage in the first active power limiting value, the second active power limiting value and the third active power limiting value in the active power limiting curve can be compared respectively to determine the active power minimum limiting value.

[0096] In step S131, the equivalent mechanical power upper limit and the equivalent mechanical power lower limit are determined according to the preset equivalent mechanical power determination mode and the active power minimum limiting value.

[0097] The preset equivalent mechanical power determination mode can be: m_H min(P L1 *P L2 ,P L3_dischrg ); P m_L =-min(P L1 *P L2 ,P L3_chrg )。

[0098] Wherein, P m_H is the equivalent mechanical power upper limit, and P m_L is the equivalent mechanical power lower limit.

[0099] According to the example embodiment, the minimum value obtained by comparing the third active power limiting value upper limit corresponding to the same grid voltage in the first active power limiting value, the second active power limiting value and the third active power limiting value in the active power limiting curve can be taken as the equivalent mechanical power upper limit, and the negative value of the minimum value in the third active power limiting value lower limit corresponding to the same grid voltage in the first active power limiting value, the second active power limiting value and the third active power limiting value in the active power limiting curve can be taken as the equivalent mechanical power lower limit.

[0100] In step S132, the virtual inertia limiting mode of the current equivalent mechanical power is determined according to the preset active power reference data.

[0101] In the present application, the preset active power reference data can include rated grid voltage angular velocity ω0, actual grid voltage angular velocity ω, active-frequency droop coefficient m, and active power reference value P ref .

[0102] According to the example embodiment, the virtual inertia limiting mode corresponding to the equivalent mechanical power of different preset active power reference data can be preset, and the current equivalent mechanical power and the corresponding virtual inertia limiting mode can be directly obtained. The application can use the virtual inertia limiting mode as follows:

[0103] P' m = P m_H , when P m > P m_H ;

[0104] , when P m_L ≤ P m ≤ P m_H ;

[0105] P' m = P m_L , when P m < P m_L .

[0106] , where P m may be used to represent the equivalent mechanical power of the grid-forming converter under the current grid voltage. P' m may be used to represent the limited equivalent mechanical power, i.e. the mechanical power limited to P m under different conditions.

[0107] In step S133, the limited equivalent mechanical power of the grid-forming converter under the grid voltage is determined according to the upper limit of the equivalent mechanical power, the lower limit of the equivalent mechanical power, the virtual inertia limiting mode and the grid voltage.

[0108] According to the example embodiment, the equivalent mechanical power of the grid-forming converter under the grid voltage is obtained by calculating according to the virtual inertia limiting mode described above. That is, in the case where the current equivalent mechanical power is greater than the upper limit of the equivalent mechanical power, the equivalent mechanical power is limited to the upper limit of the equivalent mechanical power as the limited equivalent mechanical power; in the case where the current equivalent mechanical power is less than the lower limit of the equivalent mechanical power, the equivalent mechanical power is limited to the lower limit of the equivalent mechanical power; and in the case where the current equivalent mechanical power is greater than or equal to the lower limit of the equivalent mechanical power to less than or equal to the upper limit of the equivalent mechanical power, the corresponding limited equivalent mechanical power is calculated.

[0109] The active power minimum limiting value under the grid voltage can be determined more accurately by comprehensively considering the active power limiting curve, the second active power limiting value and the third active power limiting value, and then the limiting equivalent mechanical power of the grid-connected converter under the grid voltage is accurately calculated. The upper limit and the lower limit of the equivalent mechanical power are calculated by combining the active power minimum limiting value and the preset equivalent mechanical power determination mode, which helps to provide a stable power output range in system operation and enhance the stability and reliability of the system. The virtual inertia limiting mode of the equivalent mechanical power is determined by the preset active power reference data, so that the grid-connected converter can flexibly adjust its equivalent mechanical power under different grid voltages and working conditions, and improve the adaptability and response speed of the system.

[0110] The device embodiment of the present application is described below, which can be used to execute the method embodiment of the present application. For details not disclosed in the device embodiment of the present application, reference can be made to the method embodiment of the present application.

[0111] FIG. 9 is a block diagram of a grid-connected converter active power output control device provided by an embodiment of the present application. As shown in FIG. 9, the grid-connected converter active power output control device 900 includes a limiting curve determination module 901, an overload limiting value determination module 902, a battery limiting value determination module 903 and an equivalent mechanical power determination module 904.

[0112] The limiting curve determination module 901 can determine the active power limiting curve for the grid according to the power angle stability limit parameter in the grid and the converter AC port data in the case of grid failure. The overload limiting value determination module 902 can determine the second active power limiting value for the grid according to the converter AC port data and the preset AC current overload threshold parameter. The battery limiting value determination module 903 determines the third active power limiting value for the grid according to the real-time measured battery charge and discharge parameters. The equivalent mechanical power determination module 904 can determine the limiting equivalent mechanical power of the grid-connected converter under the grid voltage for the grid according to the active power limiting curve, the second active power limiting value and the third active power limiting value.

[0113] Optionally, the limiting curve determination module 901 can specifically acquire the power angle stability limit parameter in the grid and the converter AC port data in the case of grid failure; determine the first active power limiting value under different grid voltages according to the preset power angle equation, the power angle stability limit parameter and the converter AC port data; and determine the active power limiting curve based on the first active power limiting value under different grid voltages.

[0114] Optionally, the amplitude limiting curve determination module 901 determines the static stability limit coefficient according to the power angle stability limit parameter in the case of determining the first active power amplitude limit value under different grid voltages according to the preset power angle equation, the power angle stability limit parameter and the converter AC port data; determines the AC port voltage according to the converter AC port data; determines the amplitude limit value corresponding to the power angle equation according to the static stability limit coefficient and the AC port voltage; and determines the first active power amplitude limit value corresponding to the AC port voltage as the amplitude limit value.

[0115] Optionally, the grid-connected converter active power increase control device 900 can further include a fault judgment module 905, which can determine the converter AC port voltage standard value according to the converter AC port data; and judge whether the grid has a fault according to the converter AC port voltage standard value.

[0116] Optionally, the overload amplitude limit value determination module 902 can specifically determine the converter transient maximum overload multiple according to the AC current overload threshold parameter; and determine the second active power amplitude limit value according to the AC port voltage in the converter AC port data and the converter transient maximum overload multiple.

[0117] Optionally, the battery amplitude limit value determination module 903 can specifically determine the real-time operation limit value and the battery voltage according to the preset battery charging and discharging parameter; determine the third active power amplitude limit value upper limit and the third active power amplitude limit value lower limit based on the real-time operation limit value, the battery voltage, the real-time calculated converter conversion efficiency and the preset converter rated active power, so as to determine the third active power amplitude limit value as the third active power amplitude limit value upper limit and the third active power amplitude limit value lower limit.

[0118] Optionally, the equivalent mechanical power determination module 904 can specifically determine the active power minimum amplitude limit value under the grid voltage according to the active power amplitude limit curve, the second active power amplitude limit value and the third active power amplitude limit value; determine the equivalent mechanical power upper limit and the equivalent mechanical power lower limit according to the preset equivalent mechanical power determination mode and the active power minimum amplitude limit value; determine the virtual inertia amplitude limit mode of the current equivalent mechanical power according to the preset active power reference data; and determine the amplitude equivalent mechanical power of the grid-connected converter under the grid voltage according to the equivalent mechanical power upper limit, the equivalent mechanical power lower limit, the virtual inertia amplitude limit mode and the grid voltage.

[0119] The device performs similar functions to the method provided above, and other functions can be referred to the foregoing description, which will not be described here.

[0120] FIG. 10 is a structural schematic diagram of an electronic device provided by the embodiment of the application. As shown in FIG. 10, the electronic device 1000 of the embodiment can include a memory 1001 and a processor 1002.

[0121] The computer program stored in the memory 1001 causes the aforementioned processor 1002 to perform the method in the above embodiments when the computer program is executed by the processor 1002.

[0122] The processor 1002 is connected with the memory 1001, for example, through a bus.

[0123] Optionally, the electronic device 1000 can further include a transceiver. It should be noted that the transceiver in actual application is not limited to one, and the structure of the electronic device 1000 does not constitute a limitation to the embodiments of the present application.

[0124] The processor 1002 can be a CPU (Central Processing Unit, central processor), a general-purpose processor, a DSP (Digital Signal Processor, data signal processor), an ASIC (Application Specific Integrated Circuit, application specific integrated circuit), an FPGA (Field Programmable Gate Array, field programmable gate array) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logical blocks, modules and circuits described in combination with the disclosure of the present application. The processor 1002 can also be a combination of computing functions, such as one or more microprocessor combinations, combinations of DSP and microprocessor, etc.

[0125] The bus can include a channel for transmitting information between the above components. The bus can be a PCI (Peripheral Component Interconnect, peripheral component interconnect) bus or an EISA (Extended Industry Standard Architecture, extended industry standard architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, only one thick line is shown in FIG. 10, but it does not mean that there is only one bus or only one type of bus.

[0126] The memory 1001 can be a ROM (Read Only Memory) or other type of static storage device that can store static information and instructions, a RAM (Random Access Memory) or other type of dynamic storage device that can store information and instructions, an EEPROM (Electrically Erasable Programmable Read-Only Memory), a CD-ROM (Compact Disc Read-Only Memory) or other optical disk storage, a magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program codes in the form of instructions or data structures and that can be accessed by a computer, but is not limited thereto.

[0127] The memory 1001 is used to store application program codes for implementing the solutions of the present application, and is controlled by the processor 1002 to perform. The processor 1002 is used to execute the application program codes stored in the memory 1001 to realize the content shown in the foregoing method embodiments.

[0128] The electronic device includes, but is not limited to, a mobile terminal such as a mobile phone, a notebook computer, a digital broadcast receiver, a PDA (Personal Digital Assistant), a PAD (Tablet Personal Computer), a PMP (Portable Multimedia Player), a vehicle terminal (such as a vehicle navigation terminal), and the like, and a fixed terminal such as a digital TV, a desktop computer, and the like. It can also be a server or the like. The electronic device shown in FIG. 10 is only an example, and should not bring any limitation to the functions and use range of the embodiments of the present application.

[0129] The electronic device of the present embodiment can be used to execute the method of any of the foregoing embodiments, and has similar implementation principles and technical effects, which will not be described herein.

[0130] The present application also provides a non-transitory computer-readable storage medium having computer-readable instructions stored thereon, and the processor executes the method in the above embodiments when the instructions are executed.

[0131] Those skilled in the art can understand that all or part of the steps of the foregoing method embodiments can be completed by program instruction related hardware. The foregoing program can be stored in a non-transitory computer-readable storage medium. The program, when executed, performs steps including the foregoing method embodiments; and the foregoing storage medium includes a ROM, a RAM, a magnetic disk or an optical disk, and various other media that can store program codes.

[0132] The above has introduced the embodiments of the present application in detail, and the principles and implementation manners of the present application are described by applying specific examples. The above embodiment descriptions are only used to help understand the method of the present application and its core idea. Meanwhile, the changes or deformations made by the person skilled in the art according to the idea of the present application, based on the specific implementation manners and application scope of the present application, all belong to the protection scope of the present application. In summary, the content of the present specification should not be understood as the limitation of the present application.

Claims

1. A method for controlling the increased active power generation of a grid-connected converter, characterized in that, The method comprises: In the case of power grid failure, according to the power angle stability limit parameter in the power grid and the converter AC port data, determine the active power limiting curve for the power grid; According to the converter AC port data and the preset AC current overload threshold parameter, determine the second active power limiting value for the power grid; According to the real-time measured battery charging and discharging parameters, determine the third active power limiting value for the power grid; According to the active power limiting curve, the second active power limiting value and the third active power limiting value, determine the limiting equivalent mechanical power of the grid-connected converter under the grid voltage for the power grid.

2. The method of claim 1, wherein, The method comprises: In the case of power grid failure, obtain the power angle stability limit parameter in the power grid and the converter AC port data; According to the preset power angle equation, the power angle stability limit parameter and the converter AC port data, determine the first active power limiting value under different grid voltages; Based on the first active power limiting value under different grid voltages, determine the active power limiting curve.

3. The method of claim 2, wherein, The method comprises: According to the power angle stability limit parameter, determine the static stability limit coefficient; According to the converter AC port data, determine the AC port voltage; According to the static stability limit coefficient and the AC port voltage, determine the limiting value corresponding to the power angle equation; Determine the limiting value as the first active power limiting value corresponding to the AC port voltage.

4. The method of claim 1, wherein, The method further comprises: According to the converter AC port data, determine the converter AC port voltage unit value; According to the converter AC port voltage unit value, determine whether the power grid is in failure.

5. The method of claim 3, wherein, The method comprises: According to the preset AC current overload threshold parameter, determine the converter transient maximum overload multiple; According to the AC port voltage in the converter AC port data and the converter transient maximum overload multiple, determine the second active power limiting value.

6. The method of claim 1, wherein, The method comprises: According to the battery charging and discharging parameters, determine the real-time operation limit value and the battery voltage; Based on the real-time operation limit value, the battery voltage, the real-time calculated converter conversion efficiency and the preset converter rated active power, determine the third active power limiting value upper limit and the third active power limiting value lower limit, so as to determine the third active power limiting value upper limit and the third active power limiting value lower limit as the third active power limiting value.

7. The method according to any one of claims 1 to 6, characterized in that, determining, according to the active power limiting curve, the second active power limiting value and the third active power limiting value, a limited equivalent mechanical power of a grid-connected converter under a grid voltage for the power grid; determining, according to the active power limiting curve, the second active power limiting value and the third active power limiting value, a minimum active power limiting value under the grid voltage; determining, according to the preset equivalent mechanical power determination mode and the minimum active power limiting value, an upper limit of equivalent mechanical power and a lower limit of equivalent mechanical power; determining, according to preset active power reference data, a virtual inertia limiting mode of the current equivalent mechanical power; determining, according to the upper limit of equivalent mechanical power, the lower limit of equivalent mechanical power, the virtual inertia limiting mode and the grid voltage, the limited equivalent mechanical power of the grid-connected converter under the grid voltage.

8. A network-forming converter over-issue active power control device, characterized by, comprising: a limiting curve determination module configured to determine, in the case of a grid fault, an active power limiting curve for the power grid according to an angle stability limit parameter in the power grid and converter AC port data; an overload limiting value determination module configured to determine, according to the converter AC port data and a preset AC current overload threshold parameter, a second active power limiting value for the power grid; a battery limiting value determination module configured to determine, according to real-time measured battery charging and discharging parameters, a third active power limiting value for the power grid; an equivalent mechanical power determination module configured to determine, according to the active power limiting curve, the second active power limiting value and the third active power limiting value, a limited equivalent mechanical power of a grid-connected converter under a grid voltage for the power grid.

9. An electronic device, comprising: comprising: a processor; a memory storing a computer program, which, when executed by the processor, causes the processor to perform the grid-connected converter active power increasing control method according to any one of claims 1-7.

10. A non-transitory computer-readable storage medium, comprising: a computer readable instruction stored thereon, which, when executed by a processor, causes the processor to perform the grid-connected converter active power increasing control method according to any one of claims 1-7.

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