Power electronic system stability resilience evaluation method based on multi-granularity hybrid equivalence

Abstract

The application discloses a power electronic system stability and toughness evaluation method based on multi-granularity hybrid equivalent, and belongs to the technical field of power system stability analysis; the method comprises the following steps: dividing a power electronic system into multiple granularity model partitions, wherein model partition granularity comprises detailed model partitions and equivalent model partitions; using a multi-region hybrid equivalent method to couple the dynamic behaviors of power electronic equipment in the detailed model partitions and equivalent equipment in the equivalent model partitions, establishing a stability model of the power electronic system, solving the stability model through simulation, and mastering the dynamic characteristics of the power electronic system under different granularities; and evaluating the stability and toughness of the power electronic system based on the stability model, and simulating the voltage and current characteristics of the power electronic system under multiple different disturbance conditions. The application only focuses on the port characteristics of the system, does not involve the detailed structure and parameters of the system, is suitable for stability and toughness analysis of complex power electronic systems, and has good feasibility and practical value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power system stability analysis, and particularly relates to a power electronic system stability resilience evaluation method based on multi-granularity hybrid equivalence. BACKGROUND

[0002] With large-scale power electronic devices such as renewable energy, converters, and energy storage systems connected to the power grid, traditional power system stability evaluation methods are facing challenges. Due to the fast dynamic characteristics and nonlinear behavior of power electronic devices, traditional methods are inefficient and inaccurate in dealing with complex power systems, especially in large-scale power systems. How to quickly and accurately evaluate the stability and resilience of the system has become an important problem.

[0003] The complexity of modern power systems requires more detailed and flexible modeling methods. Traditional single modeling methods cannot simultaneously consider the dynamic behavior of power electronic devices and the stability of traditional grid elements. Therefore, power systems need to use multi-granularity modeling methods to describe the different characteristics of different parts of the power system in multiple dimensions. Although there are various power system stability evaluation methods, such as transient stability analysis based on differential equations, steady-state stability analysis based on equivalent models, and adaptive control methods based on state space, they still have obvious accuracy problems when facing the complex impact of power electronic devices on grid stability, and it is difficult to accurately verify the complex coupling characteristics between power electronic devices in new power systems.

[0004] To solve the above problems, the application provides a power electronic system stability resilience evaluation method based on multi-granularity hybrid equivalence. SUMMARY

[0005] To solve the problems in the prior art, the application provides a power electronic system stability resilience evaluation method based on multi-granularity hybrid equivalence.

[0006] The object of the application can be achieved by the following technical solutions:

[0007] The power electronic system stability resilience evaluation method based on multi-granularity hybrid equivalence includes the following steps:

[0008] The power electronic system is divided into multiple granularity model partitions, including detailed model partitions and equivalent model partitions;

[0009] The dynamic behavior of power electronic devices in the detailed model partitions and equivalent devices in the equivalent model partitions is coupled using a multi-region hybrid equivalence method between the model partitions, a stability model of the power electronic system is established, the dynamic characteristics of the power electronic system under different granularities are mastered by simulating and solving the stability model.

[0010] The stability toughness of power electronic systems is evaluated based on a stability model, and the voltage and current characteristics of power electronic systems are simulated under various disturbance conditions.

[0011] Furthermore, the power electronic devices in the detailed model partition include inverters, converters, and energy storage devices. The model of the detailed model partition is established based on the improved node matrix equation. The voltage and current states and conduction states of the power electronic devices are calculated in each simulation step. The dynamic behavior of the power electronic devices is described by dynamic circuit simulation based on control strategies.

[0012] Furthermore, the equivalent model partition does not contain specific circuit devices. The port characteristics are described by port controlled voltage sources / controlled current sources and variable resistors through functions, lookup tables, and substitution methods. The equivalence of time-varying and non-time-varying complex circuits is achieved through Thevenin equivalence of voltage / impedance on the series port of the output partition and Norton equivalence of current / admittance on the parallel port.

[0013] Furthermore, the steps for evaluating the stability resilience of power electronic systems based on stability models include:

[0014] 1) Based on the partitioning results in the complete simulation model, count the number of all series loops and parallel nodes in the model partition, and assign a number to each series loop and parallel node to obtain the global coupling vector iu;

[0015] 2) Establish improved node voltage equations in detailed model partition j;

[0016] 3) Introduce the permutation matrix S in the detailed model partition j. j Modify and improve the node voltage equations;

[0017] 4) Based on the modified and improved node voltage equations, the detailed model partition j-impedance / admittance hybrid interface G is obtained. j And detailed model partitioning j voltage source / current source hybrid excitation e j ;

[0018] 5) Based on the detailed model, partition the series node current i in section j. sj Parallel node voltage u pj The relationship between the global coupling vector iu and the detailed model partition j defines the coupling mapping matrix M. j :

[0019] 6) In the equivalent model partition k, use the function group g s g p Based on the equivalent model, partition the k-series node current i sk Parallel node voltage u pkAnd the simulation time t, calculating the equivalent model partition k impedance / admittance hybrid interface G k And equivalent model partition k voltage source / current source hybrid excitation e k ;

[0020] 7) Based on the equivalent model, partition the k-series node current i sk Parallel node voltage u pk The relationship with the coupling vector iu is defined by the equivalent model partition k coupling mapping matrix M. k :

[0021] 8) In each simulation step, after completing the global mapping to obtain the mixed interface and mixed excitation of all detailed model partitions j and equivalent model partitions k, the mixed impedance / admittance interface and mixed excitation of each partition interface are added together to calculate the global coupling vector iu, thereby obtaining the series current i connecting different partitions in the circuit model. s and parallel voltage u p ;

[0022] 9) In each simulation step, the global coupling vector iu is substituted into the detailed model partition, and the node voltage u inside the detailed model partition j is calculated. j And calculate the current and device status.

[0023] Furthermore, the global coupling vector iu is [i s1 , ..., i sm u p1 , ..., u pn ]; where i s1 ... sm These are series circuits s1, ..., s m The corresponding series current; u p1 ... u pn These are parallel nodes p1, ..., p2. n The corresponding parallel voltage.

[0024] Furthermore, for the stability model, the scanning node response is observed by changing the port voltage / impedance at the series port, and by changing the port current / admittance at the parallel port.

[0025] A power electronic system stability and toughness assessment system based on multi-granularity hybrid equivalent includes:

[0026] Model partitioning module: Divides the power electronic system into multiple granular model partitions, including detailed model partitions and equivalent model partitions;

[0027] Model partition coupling module: The dynamic behavior of power electronic devices in the detailed model partition and the equivalent devices in the equivalent model partition are coupled using a multi-region hybrid equivalent method to establish a stability model of the power electronic system. The dynamic characteristics of the power electronic system at different granularities are understood by solving the stability model through simulation.

[0028] And, the evaluation module: based on the stability model, it evaluates the stability and toughness of the power electronic system and simulates the voltage and current characteristics of the power electronic system under various disturbance conditions.

[0029] A computer storage medium storing a readable program, which, when executed, can perform the aforementioned method for evaluating the stability and toughness of power electronic systems based on multi-granularity hybrid equivalence.

[0030] An electronic device includes: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus;

[0031] The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the above-described power electronic system stability and toughness assessment method based on multi-granularity hybrid equivalence.

[0032] A computer program product includes computer instructions that instruct a computing device to perform operations corresponding to the above-described power electronic system stability and resilience assessment method based on multi-granularity hybrid equivalence.

[0033] The beneficial effects of this invention are:

[0034] 1. The evaluation method of this invention focuses on combining multi-granularity hybrid equivalent modeling and stability toughness assessment, providing a novel evaluation approach. This method captures the dynamic characteristics of the power system by combining detailed model partitioning and equivalent model partitioning for different regions of the power system, and handles the coupling relationship between regions through hybrid equivalence. Specifically, the core circuit is modeled using a detailed model, while the non-core parts are modeled using a simplified equivalent model. This design simplifies calculations and improves efficiency.

[0035] 2. The key to this invention's evaluation lies in simulating the response to disturbances such as grid faults and load fluctuations at the hybrid equivalent partition interface, thereby assessing the stability and resilience of the power system. The method of this invention focuses only on the port characteristics of the system, avoiding involvement of detailed internal structure and parameters, thus effectively protecting the system's confidentiality.

[0036] 3. The evaluation method of the present invention is particularly suitable for dealing with the complexity analysis of complex AC / DC interconnected systems under new power systems, and provides an efficient and safe solution for evaluating the stability and resilience of the system. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram illustrating the principle of multi-granularity hybrid equivalent modeling in this invention;

[0039] Figure 2 This is a schematic diagram of the hybrid equivalent partitioning mapping and solution of the present invention;

[0040] Figure 3 This is a schematic diagram of the stable toughness hybrid equivalent evaluation method of the present invention;

[0041] Figure 4 This is a flowchart of the multi-granularity mixing equivalent simulation of the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1

[0044] The method for evaluating the stability and toughness of power electronic systems based on multi-granularity hybrid equivalents includes the following steps:

[0045] Step 1: Divide the power electronic system into multiple granular model partitions, including detailed model partitions and equivalent model partitions;

[0046] Compared to traditional power systems, novel power systems exhibit various series and interactive coupling structures, and the internal models of power electronic devices are more complex. To improve the simulation efficiency of complex topologies in novel power systems, this invention proposes a resilience assessment method based on... Figure 1The hybrid equivalent principle illustrated here centers on the effective coupling of detailed model partitions and equivalent model partitions. This coupling links the dynamic models of grid components and power electronic devices with the simplified equivalent models. A unified analysis is performed on the steady-state characteristics such as power flow and voltage between partitions, as well as the dynamic control strategies within the detailed model. The control systems of power electronic devices (such as inverter current regulation and energy storage system charging and discharging control) need to be integrated with the traditional steady-state model of the power grid to form a complete power system model. This fusion of dynamic behavior and control strategies, achieved through the integration of macroscopic and microscopic dynamic behaviors, enables hybrid modeling of the power grid system. This modeling approach accurately reflects the impact of power electronic devices on grid frequency, voltage, and power flow.

[0047] Circuit partitioning can be divided into detailed model partitioning and equivalent model partitioning, representing different granularities of the simulation model. For example... Figure 1 As shown, the detailed model partitioning, based on the improved node method, details the voltage and current relationships between each node and device within the partition, as well as the dynamic changes in mixed impedance / admittance and voltage / current source excitation caused by the conduction and closure actions of power electronic devices. This accurately reflects the characteristics within the partition and is suitable for circuit sections requiring detailed analysis. The detailed model partitioning includes specific circuit devices, including but not limited to: power electronic devices such as inverters, converters, and energy storage devices. The model of the detailed model partitioning is established based on the improved node matrix equation. In each simulation step, the voltage and current states and conduction states of the devices are calculated. The dynamic behavior of the devices is described through dynamic circuit simulation based on control strategies.

[0048] The equivalent model, on the other hand, ignores the characteristics within the partition and only considers the Thevenin or Norton equivalent output at the port under the current simulation step. More detailed model partitions offer faster computation speed and a wider range of circuit equivalence, suitable for circuit characteristics implemented with arbitrary equivalents. The equivalent model partitions do not contain specific circuit components; they describe port characteristics using controlled voltage / current sources and variable resistors through functions, lookup tables, and substitution. By using Thevenin equivalence of voltage / impedance on series ports and Norton equivalence of current / admittance on parallel ports in the output partition, equivalence is achieved for complex time-varying and non-time-varying circuits.

[0049] Step 2: The dynamic behavior of power electronic devices in the detailed model partition and equivalent devices in the equivalent model partition is coupled using a multi-region hybrid equivalent method to establish a stability model of the overall power electronic system. The dynamic characteristics of the power electronic system at different granularities are understood by solving the stability model through simulation.

[0050] The interconnection principle between detailed model partitions and equivalent model partitions is as follows: Figure 2 As shown. In the detailed circuit model partition j, the external series current excitation is and parallel voltage excitation u p And the equivalent current excitation h within the partition j Both will generate a series port voltage u at the serial port of the partition. sj and parallel port current i pj For the equivalent circuit model partition k, the external series current excitation i s and parallel voltage excitation u p Through function calculations, the mixed impedance / admittance and excitation of the k-port partition are generated, simulating the linear or nonlinear characteristics of the circuit partition. For parts of large-scale systems where detailed internal characteristics are not of concern, the equivalent circuit can effectively simulate the complex characteristics of the circuit. From the perspective of port equivalence, the equivalent model partition is equivalent to a function-controlled parallel current source and variable admittance on the parallel port, and a function-controlled series voltage source and variable resistor on the series port. In the series loop, according to KVL law, the series current vector i is calculated. s Solve for the parallel circuit by applying Kirchhoff's Law (KCL) to obtain the voltage vector u at the parallel nodes. p Please provide a solution.

[0051] Figure 3 The stability resilience scanning method described in this embodiment is essentially a scanning method based on equivalent model partitioning. This method simulates the stability resilience of a power system under conditions such as short circuits, load surges, and frequency domain instability by injecting excitation signals such as square waves or variable-frequency sine waves into series or parallel ports. Since this evaluation method is based on hybrid port system stability analysis, it does not concern itself with the internal structure of the tested model, but only focuses on the characteristics of the circuit partition ports. Furthermore, considering that the generation from circuit topology to the improved node matrix is ​​a unidirectional process, the same circuit topology and parameters generate completely identical improved circuit matrices, but the same circuit matrix may correspond to multiple different combinations of topologies and parameters. Based on the stability resilience evaluation method using hybrid equivalent interfaces in this embodiment, without needing to know the detailed internal structure and parameters of the model to be verified, the measured object can be treated as a "black box," and its external characteristics can be accurately simulated, thereby verifying the stability resilience under various operating conditions. This not only ensures the confidentiality of the sensitive simulation circuit structure and parameters but also enables the evaluation of the stability resilience of sensitive simulation models.

[0052] Step 3: Evaluate the stability and resilience of the power electronic system based on the stability model, and simulate the voltage and current characteristics of the system under various disturbance conditions (including faults, load fluctuations, wideband scanning, etc.).

[0053] The specific process for evaluating the stability resilience of power electronic systems based on the stability model is as follows:

[0054] 1) Based on the partitioning results in the complete simulation model, count the number of all series loops and parallel nodes in the model partition, and assign a number to each series loop and parallel node to obtain the coupling vector iu;

[0055] like Figure 1 As shown, the number of series loops is m and the number of parallel nodes is n. Each series loop is uniquely numbered s1, ..., s2. m Each parallel node is uniquely numbered as p1, ..., p n Series and parallel connections are inherent properties of each partition in the model when connected to other external ports. Series loops s1, ..., s2 are examples of such connections. m The corresponding series currents are i s1 ... sm Parallel nodes p1, ..., p n The corresponding parallel voltages are u p1 ... u pn According to the numbering order of series circuits and parallel nodes s1, ..., s2 m p1, ..., p n , will the global coupling vector [i s1 , ..., i sm u p1 , ..., u pn It is written as iu.

[0056] 2) Establish improved node voltage equations in detailed model partition j;

[0057] The improved node voltage equation is as follows:

[0058] u j =Z j (h j +y j )

[0059] Among them, u j It is the sub-partition node voltage vector, Z j It is the sub-partition impedance matrix, h j It is the node current vector corresponding to the node voltage vector, y j It is the current and voltage vector injected into the detailed model partition j from other partitions of the model through series and parallel nodes. If the nodes in the partition are not connected to the external partitions, its value in y is... j The corresponding position is 0.

[0060] 3) Introduce the permutation matrix S in the detailed model partition j. j The order of impedance and current positions in the node voltage equations was modified and improved; the specific modification process involves the following expressions:

[0061]

[0062] Among them, u rj This represents the node voltage vector corresponding to the internal node, SZS1j, SZS2j, and SZS3j are the block impedances corresponding to the internal nodes, and h is the node voltage vector corresponding to the internal node. rj It is the node current source corresponding to the internal node, u sj SZS4j, SZS5j, and SZS6j are the node voltage vectors corresponding to the external series nodes, and h is the block impedance corresponding to the external series nodes. sj It is the node current source corresponding to the external series node, i sj It is the series current injected by the external partition into the series node of the detailed model partition j (i.e., the series node current of the detailed model partition j), u pj This is the node voltage vector corresponding to the external series node (i.e., the parallel node voltage of the detailed model partition j), SZS7j, SZS8j, and SZS9j are the block impedances corresponding to the external series nodes, and h pj It is the node current source corresponding to the external series node, i pj It is the series current injected from the external partition into the series node of the detailed model partition j.

[0063] 4) Based on the improved node voltage equations modified for the detailed model partition j, the impedance / admittance hybrid interface G for the detailed model partition is obtained. j And detailed model partitioning voltage source / current source hybrid excitation e j：

[0064]

[0065]

[0066] 5) Based on the detailed model, partition the series node current i in section j. sj Parallel node voltage u pj With coupling vector iu=[i s1 , ..., i sm u p1 , ..., u pn The relationship between [] is defined, and the coupling mapping matrix M in the detailed model partition j is defined. j :

[0067]

[0068] Among them, P j It is a series interface coupling matrix that satisfies the definition:

[0069]

[0070] Among them, Q jIt is a parallel interface coupling matrix that satisfies the definition:

[0071]

[0072] In a series circuit, the Thevenin equivalent impedance and excitation can be linearly added, and in a parallel circuit, the Norton equivalent admittance and excitation can be linearly added. Therefore, the detailed model obtained in step 4) partitions the impedance / admittance hybrid interface G. j Mapped to the global model as M j G j MT j, hybrid excitation e j Mapped to the global model as M j e j .

[0073] 6) In the equivalent model partition k, there are no specific nodal voltage equations. The series interface consists of the Thevenin equivalent impedance and voltage source, while the parallel interface consists of the equivalent admittance and current source, all of which are composed of the function set g. s g p Based on the equivalent model, partition the k-series node current i sk Parallel node voltage u pk The simulation time t is used to calculate the series impedance and parallel admittance at the hybrid interface G. k On the diagonal line, M k The equivalent model partition k and coupling vector iu = [i s1 , ..., i sm u p1 , ..., u pn The coupling mapping matrix of ];

[0074] The equivalent model partitioned impedance / admittance hybrid interface G k The form satisfies the following function group:

[0075]

[0076] Partitioned voltage source / current source hybrid excitation e k The form satisfies the following function group:

[0077]

[0078] Interface function group g in equivalent partition k s g p Excitation function group e s e p It is a function in a general sense, which can realize linear, nonlinear, time-varying, time-invariant, memoized, and memoized functions.

[0079] 7) Based on the equivalent model, partition the k-series node current i sk Parallel node voltage upk With coupling vector iu=[i s1 , ..., i sm u p1 , ..., u pn The relationship between ] is defined, and the coupling mapping matrix M in the detailed model partition k is defined. k :

[0080]

[0081] The equivalent model obtained in step 6) partitions the impedance / admittance hybrid interface G. k Mapped to the global model as M k G k MT k, hybrid excitation e k Mapped to the global model as M k e k .

[0082] 8) In each simulation step, complete the global mapping to obtain the hybrid interface M of all detailed model partitions and equivalent model partitions. j G j MT j, M k G k MT k, Hybrid excitation M j e j、 M k e k Then, by adding the hybrid impedance / admittance interfaces and hybrid excitation components of each partition interface, the global coupling vector iu is calculated, which yields the series current i connecting different partitions in the large-scale circuit model. s and parallel voltage u p ;

[0083] The formula for calculating the global coupling vector iu is:

[0084]

[0085] In this context, the subscript i can refer to j and k;

[0086] 9) In each simulation step, the coupling vector iu is substituted into the detailed model partition, and the node voltage u inside the detailed model partition j is calculated. j And calculate the current and device status, the calculation formula is:

[0087]

[0088] For the stability model, the scanning node response is observed by changing the port voltage / impedance at the series port, and by changing the port current / admittance at the parallel port.

[0089] The transient and steady-state stability of the power system under various disturbances such as short-circuit faults, load fluctuations, and renewable energy generation fluctuations are analyzed and evaluated. Based on the evaluation results, an optimized control strategy for power electronic equipment is proposed to improve the resilience and recovery capability of the power system.

[0090] Multi-granularity mixing equivalent simulation process as follows Figure 4 As shown, it includes the following steps:

[0091] S1 calculates the impedance / admittance hybrid matrix of the internal partitions of the detailed model;

[0092] For partitions containing power electronic or multi-state devices, the complete set of mixed impedance / admittance matrices for partition j in n states can be pre-enumerated.

[0093] S2, Initialize the internal state related to the function within the equivalent model partition;

[0094] S1 and S2 are the partition initialization steps. After the initial state of the partition is initialized, the step-by-step calculation process from S3 to S16 begins.

[0095] S3, proceed to the next simulation step.

[0096] S4 calculates time-related variables in the detailed and equivalent model partitions and updates the state.

[0097] S5, Select the hybrid impedance / admittance matrix based on the detailed model partition j and the power electronic device state combination k.

[0098] S6, Based on the detailed model partitioning, j-mixed impedance / admittance matrix Calculate the hybrid port excitation e j .

[0099] S7, calculate the impedance / admittance hybrid mapping matrix M for each partition. j G j MT j, M k G k MT k, and after completing the calculations for each partition, calculate the sum of the global impedance / admittance hybrid mapping matrix: ΣM i G i MT i.

[0100] S8, calculate the voltage / current source hybrid excitation mapping vector M for each partition. j e j、 M k e k And after completing the calculations for each partition, the sum of the global hybrid excitation mapping matrix is ​​obtained: ΣM i e i .

[0101] S9, calculate the global series current and parallel voltage coupling vector iu, the calculation formula is:

[0102]

[0103] S10, substituting the global coupling vector iu, calculates the node voltage within partition j of the detailed model. The calculation formula satisfies:

[0104]

[0105] S11, determine whether a device state switch has occurred in the detailed model partition; if no device state switch has occurred in S11 and the global device state has converged, proceed to S14; if a state change occurs in power electronic or other multi-state devices, proceed to S12 for state switching processing, and then in S13, update the devices in the partition to the latest state and return to S5 for recalculation.

[0106] S12, State transition processing;

[0107] S13, update the devices in the partition to the latest state, and return to S5 to recalculate;

[0108] S14, bring the global coupling vector iu into the equivalent model partition, update the relevant state of the coupling vector iu in the partition, and output the corresponding equivalent impedance / admittance, voltage source excitation / current source excitation on the port.

[0109] S15 uses the latest circuit status to operate the control module within the partition for device control.

[0110] S16: Determine if the simulation duration has been reached; if the simulation has not ended, jump to S3 to continue the simulation; if the simulation end time has been reached, terminate the simulation.

[0111] The established model was validated through simulation to verify the effectiveness and accuracy of the method under different disturbance conditions. By comparing the simulation results with the actual system behavior, the model parameters were adjusted to improve the system's stability and resilience.

[0112] Based on a similar inventive concept, embodiments of the present invention also provide a computer storage medium storing a readable program that, when the program is run, can execute the above-described method for evaluating the stability and toughness of power electronic systems based on multi-granularity hybrid equivalence.

[0113] Based on a similar inventive concept, this invention provides an electronic device, including: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus;

[0114] The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the above-described power electronic system stability and toughness assessment method based on multi-granularity hybrid equivalence.

[0115] Based on a similar inventive concept, embodiments of the present invention also provide a computer program product, including computer instructions, which instruct a computing device to perform the operations corresponding to the above-described power electronic system stability and toughness assessment method based on multi-granularity hybrid equivalence.

[0116] Example 2

[0117] Based on the power electronic system stability toughness assessment method based on multi-granularity hybrid equivalence proposed in Example 1, this example proposes a power electronic system stability toughness assessment system based on multi-granularity hybrid equivalence, including:

[0118] Model partitioning module: Divides the power electronic system into multiple granular model partitions, including detailed model partitions and equivalent model partitions;

[0119] Model partition coupling module: The dynamic behavior of power electronic devices in the detailed model partition and the equivalent devices in the equivalent model partition are coupled using a multi-region hybrid equivalent method to establish a stability model of the power electronic system. The dynamic characteristics of the power electronic system at different granularities are understood by solving the stability model through simulation.

[0120] And, the evaluation module: based on the stability model, it evaluates the stability and toughness of the power electronic system and simulates the voltage and current characteristics of the power electronic system under various disturbance conditions.

[0121] The methods of the present invention can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CD-ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code originally stored on a remote recording medium or a non-transitory machine-readable medium and subsequently stored on a local recording medium, downloaded via a network. Thus, the methods described herein can be processed by software stored on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It is understood that the computer, processor, microprocessor controller, or programmable hardware includes storage components (e.g., RAM, ROM, flash memory, etc.) capable of storing or receiving software or computer code that, when accessed and executed by the computer, processor, or hardware, implements the methods described herein. Furthermore, when a general-purpose computer accesses the code used to implement the methods shown herein, the execution of the code transforms the general-purpose computer into a dedicated computer for performing the methods shown herein.

[0122] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for power electronics system stability robustness assessment based on multi-granularity hybrid equivalence, characterized in that, The method comprises the following steps: dividing the power electronic system into multiple granularity model partitions, including detailed model partitions and equivalent model partitions; using a multi-region hybrid equivalent method to couple the dynamic behaviors of the power electronic devices in the detailed model partitions and the equivalent devices in the equivalent model partitions, establishing a stability model of the power electronic system, solving the stability model through simulation, and mastering the dynamic characteristics of the power electronic system under different granularities; evaluating the stability and toughness of the power electronic system based on the stability model, and simulating the voltage and current characteristics of the power electronic system under multiple different disturbance conditions; the power electronic devices in the detailed model partitions include inverters, converters, and energy storage devices, and a model of the detailed model partitions is established based on an improved node matrix equation, the voltage and current states and conduction states of the power electronic devices are calculated in each simulation step, and the dynamic behaviors of the power electronic devices are described through dynamic circuit simulation based on a control strategy; the equivalent model partitions do not contain specific circuit devices, and the port characteristics are described by port-controlled voltage sources / controlled current sources and variable resistors through functions, lookup tables, and substitution methods; the Thevenin equivalence of the voltage / impedance on the series port and the Norton equivalence of the current / admittance on the parallel port are used to achieve the equivalence of complex circuits with time-varying and non-time-varying characteristics.

2. The method for power electronics system stability robustness assessment based on multi-granularity hybrid equivalence of claim 1, wherein, The step of evaluating the stability and toughness of the power electronic system based on the stability model comprises: 1) According to the partition results in the complete simulation model, the number of series loops and parallel nodes in the model partitions is counted, each series loop and parallel node is numbered, and a global coupling vector iu is obtained; 2) in the detailed model partition j establishing an improved node voltage equation; 3) introducing a substitution matrix S in the detailed model partition j j , modifying the improved node voltage equation;​ 4) Obtain detailed model partition according to modified improved node voltage equation j Impedance / admittance hybrid interface G j , and detailed model partition j Voltage source / current source hybrid excitation e j ; 5) Detailed model partitioning j Series node current i sj Parallel node voltage u pj Detailed model partitioning in relation to global coupling vector iu j Coupling mapping matrix M j in 6) in the equivalent model partition k using a function group g s , g p According to the equivalent model partition k the series node current i sk , the parallel node voltage u pk and the simulation time t， The equivalent model partition k impedance / admittance hybrid interface G k and the equivalent model partition k voltage / current source hybrid excitation e k ; 7) Partitioning according to equivalent models k Series node current i sk Parallel node voltage u pk Relation to coupling vector iu, defining equivalent model partitioning k Coupling mapping matrix M k : 8) In each step of simulation, the global mapping is done to get all the detailed model partitions j and equivalent model partitions k After the hybrid interface and hybrid excitation, the hybrid impedance / admittance interface of each partition interface part and the hybrid excitation part are added to calculate the global coupling vector iu to get the series current i between different partitions in the circuit model s and parallel voltage u p ; 9) At each step of the simulation, the global coupling vector iu is brought into the detailed model partition, which computes the detailed model partition j Internal node voltages u j and computes currents and device states.

3. The method for power electronics system stability robustness assessment based on multi-granularity hybrid equivalence according to claim 2, characterized in that, The global coupling vector iu is i s1 ,..., i sm , u p1 ,..., u pn ] ; wherein i s1 ,..., i sm are the respective series currents s 1,..., s m are the respective series voltages u p1 ,..., u pn are the respective parallel voltages p 1,..., p n are the respective parallel currents 4. The method for power electronics system stability robustness assessment based on multi-granularity hybrid equivalence of claim 3, wherein, for the stability model, the port voltage / impedance is changed on the series port to observe the scanning node response, and the port current / admittance is changed on the parallel port to observe the scanning node response.

5. A power electronics system stability robustness assessment system based on multi-granularity hybrid equivalent, performing the assessment method of any one of claims 1-4, characterized in that, It comprises: a model partition division module: dividing the power electronic system into multiple granularity model partitions, including detailed model partitions and equivalent model partitions; a model partition coupling module: using a multi-region hybrid equivalent method to couple the dynamic behaviors of the power electronic devices in the detailed model partitions and the equivalent devices in the equivalent model partitions, establishing a stability model of the power electronic system, solving the stability model through simulation, and mastering the dynamic characteristics of the power electronic system under different granularities; and an evaluation module: evaluating the stability and toughness of the power electronic system based on the stability model, and simulating the voltage and current characteristics of the power electronic system under multiple different disturbance conditions.

6. A computer storage medium storing a readable program, characterized in that, When the program runs, it can perform the multi-granularity hybrid equivalent-based power electronic system stability and toughness evaluation method of any one of claims 1-4.

7. An electronic device, comprising: It comprises: a processor, a memory, a communication interface, and a communication bus, which complete communication among each other through the communication bus; the memory is used to store at least one executable instruction, and the executable instruction makes the processor perform the operations corresponding to the multi-granularity hybrid equivalent-based power electronic system stability and toughness evaluation method of any one of claims 1-4.

8. A computer program product comprising computer instructions, characterized in that, The computer instructions direct the computing device to perform operations corresponding to the multi-granularity hybrid equivalent-based power electronics system stability robustness evaluation method of any one of claims 1-4.

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