Dynamic characteristics analysis method of DC power system based on mixed time scale modeling

Abstract

The embodiment of the present invention discloses a method for analyzing the dynamic characteristics of a DC power system based on hybrid time scale modeling, which relates to the technical field of power electronic systems for DC power distribution and can improve the efficiency of digital electromagnetic transient analysis. The present invention includes: establishing an EMT subsystem and a DP subsystem of a DC power system; importing the established EMT subsystem into FPGA1, and importing the established DP subsystem into FPGA2; establishing an interface calculation module according to the external characteristics of the EMT subsystem and the DP subsystem, and deploying it on FPGA3; after initialization, the EMT subsystem performs n single-step analysis and the DP subsystem performs one single-step analysis until the interaction moment is reached; and outputting the analysis results to a terminal device.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic systems for direct current power distribution, and in particular to a method for analyzing dynamic characteristics of a direct current power system based on mixed time scale modeling. Background Art

[0002] As an important carrier that integrates consumption, efficient access to electric vehicles, distribution network transformation and capacity expansion, and comprehensive energy systems, DC power distribution has become one of the development directions of future power grids and even energy Internet. However, the DC power system undertakes the AC main grid, low-voltage distribution network, and new energy power generation systems such as wind power and photovoltaic power generation. Both the source and the load are highly power-electronic. With the increase in capacity and power levels and the increase in the number of power electronic devices, the power electronic converter and control protection strategy will be extremely complex.

[0003] As an important means of analyzing and verifying the safety, stability and power supply quality characteristics of multi-terminal DC power systems, power system transient analysis is not limited by system scale and structural complexity. However, the increase in system scale and the extension of device switching frequency will make the contradiction in the efficiency of electromagnetic transient simulation more prominent (usually the integration step needs to be set to 1 / 10 of the switching cycle or even smaller). If the dynamic and static characteristics are studied based on a detailed model of the entire system and a small-scale integration step, the efficiency of digital electromagnetic transient analysis will be difficult to guarantee. Therefore, how to improve the efficiency of digital electromagnetic transient analysis at the same time has become a problem that needs to be studied. Summary of the invention

[0004] An embodiment of the present invention provides a method for analyzing dynamic characteristics of a DC power system based on hybrid time scale modeling, which can improve the efficiency and accuracy of digital electromagnetic transient analysis.

[0005] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0006] S1. Establish the EMT subsystem and DP subsystem of the DC power system;

[0007] S2, import the established EMT subsystem into FPGA1, and import the established DP subsystem into FPGA2;

[0008] S3, establish an interface computing module according to the external characteristics of the EMT subsystem and the DP subsystem, and deploy it on FPGA3, wherein the FPGA3 is used for data interaction between the EMT computing module and the DP computing module;

[0009] S4. After initialization, the EMT subsystem performs n single-step analysis and the DP subsystem performs one single-step analysis until the interaction time is reached;

[0010] S5. Output the analysis result to the terminal device.

[0011] The solution of this embodiment can be applied to the platform of dynamic phasor (DP)-electromagnetic transient (EMT) hybrid simulation of DC power system. Dynamic phasor modeling is used to process the non-concerned parts of the DC power system to be simulated to ensure the high efficiency of the simulation; electromagnetic transient modeling is used to process the concerned parts of the DC power system to be simulated to ensure the accuracy of the simulation; multi-block FPGA is used to realize interface data interaction and serial and parallel timing hybrid simulation to ensure the high efficiency of the simulation. A dynamic phasor-electromagnetic transient hybrid simulation heterogeneous platform is built to balance the accuracy and speed of DC power system simulation. The proposed dynamic phasor-electromagnetic transient hybrid simulation has small hardware restrictions on the simulation equipment and can realize the simulation of large-scale AC and DC systems; it can flexibly realize the modification of the hybrid simulation interface mode, and the modification and upgrade of the hybrid simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 , 2 A schematic diagram of a specific example provided for an embodiment of the present invention;

[0014] Figure 3 A schematic diagram of a division method of a hybrid simulation subsystem of a DC power system provided in an embodiment of the present invention;

[0015] Figure 4 A schematic diagram of the main logic flow of a hybrid simulation algorithm of a specific example provided in an embodiment of the present invention;

[0016] Figure 5 A schematic diagram of a method flow provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention. It can be understood by those skilled in the art that, unless specifically stated, the singular forms "one", "one", "said" and "the" used herein may also include plural forms. It should be further understood that the term "including" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used here may include wireless connection or coupling. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as generally understood by those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0018] The embodiment of the present invention provides a method for analyzing the dynamic characteristics of a DC power system based on mixed time scale modeling, such as Figure 5 As shown, including:

[0019] S1. Establish the EMT subsystem and DP subsystem of the DC power system.

[0020] S2. Import the established EMT subsystem into FPGA1, and import the established DP subsystem into FPGA2.

[0021] FPGA2 can also be understood as a cluster composed of multiple FPGAs. In actual applications, there may be one EMT subsystem, but there may be multiple DP subsystems, and FPGA 2 may contain multiple FPGAs.

[0022] S3. Establish an interface computing module according to the external characteristics of the EMT subsystem and the DP subsystem, and deploy it on FPGA3. The FPGA3 is used for data interaction between the EMT computing module and the DP computing module.

[0023] Among them, the logic for parallel simulation timing control can also be imported on FPGA3, so that the simulation timing control logic is used to select whether to use serial or parallel in subsequent processing. Specifically, the simulation timing control logic can be loaded into the interface calculation module deployed on FPGA3, and the interface calculation module selects whether to use serial timing simulation or parallel timing simulation in subsequent processing. Therefore, the FPGA3 is specifically used for simulation timing selection and data interaction between the EMT calculation module and the DP calculation module.

[0024] S4. After initialization, the EMT subsystem performs n single-step analysis and the DP subsystem performs one single-step analysis until the interaction time is reached.

[0025] S5. Output the analysis result to the terminal device.

[0026] Among them, S1 includes: establishing state equations of the EMT subsystem and the DP subsystem, and using FPGA2 to run the DP subsystem, wherein the state equation of the EMT subsystem is: Among them, r D is the real-time interaction amount of the DP subsystem, represents the differential term of the state variable of the EMT subsystem, A E represents the EMT subsystem state variable matrix, x E Indicates the state variable of the EMT subsystem, B E represents the EMT subsystem control variable matrix, u represents the EMT subsystem control variable, C E-D represents the interaction matrix of the EMT subsystem, E represents the EMT subsystem, D represents the DP subsystem, and the state equation of the DP subsystem is: r E is the real-time interaction quantity of the EMT subsystem, k represents the dynamic phasor order, represents the differential term of the DP subsystem state variable, x D represents the state variable of the DP subsystem, j represents the imaginary unit, ω s =2π / T, T represents the fundamental wave period, A D represents the DP subsystem state variable matrix, B D represents the DP subsystem control variable matrix, u D Represents the DP subsystem control variable, operator <x> k Represents the k-order dynamic phasor of the corresponding variable.

[0027] In practical applications, it is necessary to establish the state equation of the subsystem and use FPGA to implement subsystem simulation:

[0028]

[0029] Where: r D is the real-time interaction quantity of the DP subsystem

[0030] And establish the state equation of the DP subsystem. When it adopts dynamic phasor modeling, the state equation (2) described by the instantaneous value differential equation will be converted into (3)

[0031]

[0032] Where: r E The real-time interaction quantity of the DP subsystem:

[0033]

[0034] Where: s =2π / T, T is the fundamental period, operator <x> k Represents the k-order dynamic phasor of the corresponding variable, and its definition and solution method are as follows

[0035]

[0036] Wherein: superscript "R" and "I" represent the real part and imaginary part respectively.

[0037] Specifically, the dynamic process of the DP subsystem needs to be split into real and imaginary parts. Since computers cannot calculate differential equations containing complex numbers in practical applications, they must be expanded into two types of equations, real and imaginary, in order to be solved. <x> k This form is a complex number and can be expressed as

[0038] Due to the complex characteristics of the dynamic phasor, the real and imaginary parts of the dynamic process of the DP subsystem represented by equation (4) are split into

[0039]

[0040] R represents the real part, I represents the imaginary part, represents the real part matrix of the DP subsystem state variables, represents the imaginary part matrix of the DP subsystem state variables, represents the real part matrix of the DP subsystem control variables, represents the imaginary part matrix of the DP subsystem control variables, represents the real part matrix of the interaction quantity of the DP subsystem, represents the imaginary matrix of the interaction quantity of the DP subsystem, represents the real part of the real-time interaction quantity of the EMT subsystem, Represents the imaginary part of the real-time interaction of the EMT subsystem, represents the real part of the DP subsystem state variable, Represents the imaginary part of the DP subsystem state variable.

[0041] In this embodiment, in the process of using FPGA3 to perform data interaction between the EMT calculation module and the DP calculation module, the interface mechanism used includes:

[0042] A dynamic phasor value is extracted from the instantaneous value of the interactive quantity output by the EMT subsystem.

[0043] The interactive quantity in the form of a dynamic phasor output by the DP subsystem is used to generate an instantaneous value of the interactive quantity.

[0044] Among them, a controlled voltage source and a controlled current source are used as interface circuits for single-step solution of the EMT subsystem and the DP subsystem, and the interaction quantity is used as the controlled source amplitude.

[0045] Since the DC side external special can be roughly divided into two types: bus voltage control type and bus current control type, the controlled voltage source and the controlled current source are used as the interface circuits for the two types of subsystems in single-step solution, and the interaction quantity is the amplitude of the controlled source. Link ② is used to extract the dynamic phasor value from the instantaneous value of the interaction quantity of the EMT subsystem, while link ④ is used to generate the instantaneous value from the interaction quantity in the form of dynamic phasor of the DP subsystem.

[0046] Furthermore, the interface calculation module is built. According to the external characteristics of the EMT subsystem and the DP subsystem, the interface scheme is determined, and the simulation timing selection and the data interaction between the EMT calculation module and the DP calculation module are realized by using FPGA3. Among them, for the subsystems composed of the converter station, load converter, etc., the DC side external characteristics can be roughly divided into two types: bus voltage control type and bus current control type. Therefore, the controlled voltage source and the controlled current source are used as the interface circuits for the single-step solution of the two types of subsystems, and the interaction quantity is the amplitude of the controlled source. Figure 2 A schematic diagram of the interface mechanism is given, where links ① and ③ are the EMT and DP subsystems, link ② is used to extract dynamic phasor values ​​from the instantaneous values ​​of the interaction quantities of the EMT subsystem, and link ④ is used to generate instantaneous values ​​from the interaction quantities in the form of dynamic phasors of the DP subsystem.

[0047] In this embodiment, in step S4, the initialization process includes:

[0048] The EMT computing module of the EMT subsystem, the DP computing module and the interface computing module of the DP subsystem are initialized.

[0049] Among them, the interface calculation module is used as a bridge for the interaction between the two subsystems. The initialization process includes: the time of the three modules is synchronized and the initial time is t=t0, the simulation step length Δt of the EMT subsystem, the simulation step length ΔT=hΔt of the DP subsystem, the total simulation time T, the system parameters of the EMT calculation module and the DP calculation module, wherein t0 represents the initial time, which is generally 0, and Δt represents the simulation step length of the EMT subsystem. Δt, n is selected according to the specific actual situation, Δt is generally selected from 1 to 10 microseconds, and n is 10 to 100; the system parameters of the EMT calculation module and the DP calculation module include all the parameters in the state quantity matrix and the control quantity matrix when establishing the DP subsystem and the EMT subsystem.

[0050] In this embodiment, the hybrid simulation includes two types of methods: serial timing simulation and parallel timing simulation. Figure 2 As shown, for serial timing simulation, in step S4, the DP subsystem performs a single-step analysis, including:

[0051] At time t1, the interactive quantity in the form of dynamic phasor output by the DP subsystem generates an instantaneous value sequence through the interface and is transmitted to the EMT subsystem. The "interface" here can also be called a "hybrid simulation interface". This type of "interface" is implemented as an interface circuit at the hardware level, such as Figure 1 A controlled voltage source or current source as shown in , where Figure 1 On the left are two EMT subsystems and interface circuit forms, and on the right are the corresponding two DP subsystems. The EMT subsystem interface can be a controlled voltage source or a current source, and the corresponding DP subsystem must be a controlled current source or a controlled voltage source; Among them, single-step solution refers to: the calculation of a simulation step; interaction refers to: the amount of r when establishing the EMT subsystem and the DP subsystem E 、r D is the interaction quantity, and the value of "interaction quantity" = the value of "controlled source amplitude". The EMT subsystem reads the interaction quantity from the instantaneous value sequence and sets the interface circuit controlled source, and then analyzes according to the electromagnetic transient step until time t2. Figure 2 As shown, the moment t1 represents each interaction moment, and there are many simulations. The period between t1 and t2 is a DP subsystem simulation step ΔT. According to the analysis results obtained by the EMT subsystem, the instantaneous value sequence is updated, and the dynamic phasor value of the interaction quantity is extracted through the interface calculation module and passed to the DP subsystem, wherein the interface calculation module is used to load the Figure 1 The interface mechanism shown in FIG. 1 is used to facilitate the interaction between the DP subsystem and the EMT subsystem. When the DP subsystem executes to time t2, if the interaction interval is consistent with the DP subsystem simulation step size, only one iteration is performed. When entering the next interaction interval, the execution Figure 2 Steps ⑤ to ⑧ in a. The interaction interval is the time it takes for the interface calculation module to transfer the interaction amount each time, which is generally consistent with the DP subsystem simulation step size. In actual applications, the time it takes for the interface calculation module to transfer the interaction amount each time should not be smaller than the DP subsystem simulation step size.

[0052] Specifically, when the serial timing processing method is adopted, it includes:

[0053] Step 11: At time t1, the dynamic phasor value of the DP subsystem interaction quantity <r D > k Generate instantaneous value sequence r through hybrid simulation interface D，n = {r D，n (t),…r D，n (t+(m-1)Δt)}, it is passed to the EMT subsystem;

[0054] Step 12: The EMT subsystem obtains the instantaneous value sequence r of the interaction quantity D In the process, the interaction quantities are read in turn and the controlled source of the interface circuit is set. The simulation is performed m steps according to the electromagnetic transient step length Δt until the moment t2;

[0055] Step 13: Update the instantaneous value sequence of the interaction quantity in the period [t2-T, t2] based on the simulation results of the EMT subsystem (t1, t2), and extract the dynamic phasor value of the interaction quantity through the hybrid simulation interface <r E > k , and passed to the DP subsystem for simulation at (t1, t2];

[0056] Step 14: The DP subsystem executes with a simulation step size of ΔT until time t2. If the interaction interval is consistent with the DP subsystem simulation step size, only one iteration is performed.

[0057] When entering the next interaction interval, execute Figure 2 Steps ⑤~⑧ in a) are the same as Figure 2 a) Steps ① to ④.

[0058] For parallel timing simulation, in step S4, the EMT subsystem performs n single-step analysis, including: at time t1, the interactive quantity in the form of dynamic phasor output by the DP subsystem generates an instantaneous value sequence through the hybrid simulation interface, and then passes it to the EMT subsystem. The EMT subsystem uses the instantaneous value sequence (expressed in the form of: [t1-T, t1]) to extract the dynamic phasor value of the interactive quantity through the interface and pass it to the DP subsystem. Among them, at the interactive moment, both subsystems need to pass the interactive quantity to the interface calculation module, generate the corresponding form, and then complete the simulation of the next stage. Therefore, it can be considered that the two processes of "the interactive quantity in the form of dynamic phasor output by the DP subsystem generates an instantaneous value sequence through the hybrid simulation interface and then passes it to the EMT subsystem" and "the EMT subsystem uses the instantaneous value sequence to extract the dynamic phasor value of the interactive quantity through the interface and pass it to the DP subsystem" are carried out simultaneously.

[0059] Specifically, when the parallel sequential processing method is adopted, it includes:

[0060] Step 21: At time t1, the dynamic phasor value of the DP subsystem interaction quantity <r D > k Generate instantaneous value sequence r through hybrid simulation interface D,n = {r D,n (t),…r D,n (t+(m-1)Δt)}, and then pass it to the EMT subsystem; at the same time, the EMT subsystem uses the instantaneous value sequence of the interaction quantity in the period [t1-T, t1] to extract the dynamic phasor value of the interaction quantity through the interface <r E > k And pass it to the DP subsystem;

[0061] Step 22: The EMT subsystem and the DP subsystem perform simulation with step sizes Δt and ΔT respectively until time t2, and the DP subsystem updates the instantaneous value sequence of the interaction quantity to [t2-T, t2].

[0062] Figure 2 Steps ③ to ④ in b) correspond to the next interaction interval, and Figure 2 The execution process of steps ① to ② in b) is the same and will not be repeated here.

[0063] Note: In the serial timing simulation, the EMT subsystem is introduced as an example of the DP subsystem ahead of the EMT subsystem. In practice, the DP subsystem can also be constructed in a way that the EMT subsystem is ahead of the EMT subsystem. Due to the inconsistency of the time attributes of the interaction quantity, although the serial and parallel timing simulations are solved independently for each subsystem, there are still certain differences in convergence. Generally speaking, the convergence of serial timing simulation is relatively high, and the hardware requirements for the simulation platform are also low, but the computational efficiency is much lower than that of parallel timing simulation.

[0064] In the actual application of this embodiment, the following implementation process may also be adopted, including:

[0065] Step 101: subsystem division: According to the degree of object attention, the DC power system is divided into a detailed electromagnetic transient modeling subsystem (EMT subsystem) and a simplified dynamic phasor modeling subsystem (DP subsystem).

[0066] Step 102: Building an EMT calculation module. Importing the established EMT subsystem mathematical model program into FPGA1.

[0067] Step 103: Building a DP calculation module. Importing the established DP subsystem mathematical model program into FPGA cluster 2.

[0068] Step 104: Build an interface computing module. According to the external characteristics of the EMT subsystem and the DP subsystem, determine the interface solution, and use FPGA3 to implement simulation timing selection and data interaction between the EMT computing module and the DP computing module.

[0069] Step 105: Module initialization. The EMT calculation module, DP calculation module, and interface calculation module are initialized, including the initial time t=t0, the EMT subsystem simulation step Δt, the DP subsystem simulation step ΔT=nΔt, the total simulation time T, the simulation timing (serial timing simulation and parallel timing simulation), and the EMT and DP calculation module system parameters.

[0070] Step 106: Complete n single-step simulations of the EMT subsystem and one single-step simulation of the DP subsystem. When the interaction time is reached, the interface calculation module completes the extraction, transformation and transmission of the interaction data between the DP calculation module and the EMT calculation module.

[0071] Step 107: Determine whether the simulation is finished. If t≥T, the simulation is finished and the result is output. Otherwise, return to step 106.

[0072] If combined with Figure 3 , 4 To further describe, the present invention uses FPGA to build EMT calculation module, DP calculation module and interface calculation module to form a dynamic phasor-electromagnetic transient hybrid simulation platform to complete the DC power system hybrid simulation, balancing the efficiency and accuracy of the simulation. The specific implementation is:

[0073] Step 201: Figure 3 Taking the three-terminal VSC DC power system shown in the figure as an example, subsystem 1 consisting of converter station 1 and the DC network is the EMT subsystem, while converter stations 2 and 3 containing AC equivalent circuits are DP subsystems.

[0074] Step 202: Building an EMT calculation module. Importing the established EMT subsystem mathematical model program into FPGA1.

[0075] Step 203: Build a DP calculation module. Figure 1 Taking the DP subsystem main circuit with VSC converter station as an example, when the switching function is introduced to describe the switching process, the general expression of the dynamic phasor model of the DP subsystem main circuit is:

[0076]

[0077] Where: p∈{a, b, c} represents three phases, u sp is the equivalent power supply on the AC side, i sp is the current of each phase of the equivalent power supply on the AC side, u dc is the DC side capacitor voltage, i dc is the DC side output current, S a =2s a / 3-s b / 3-s c / 3,S b =2t b / 3-s a / 3-s c / 3,S c =2s c / 3-s a / 3-s b / 3,s p is the three-phase bridge arm switching function.

[0078] When only the dominant component of the DC power system is considered, the AC side state quantity is modeled using 1st, 5th and 7th order dynamic phasors, and the DC side state quantity is modeled using 0th and 6th order dynamic phasors. Equation (6) can be decomposed into:

[0079]

[0080] For the multivariate can be <xy> k It is obtained by expanding the dynamic phasor convolution property, that is,

[0081]

[0082] In the formula,

[0083] Import the established DP subsystem mathematical model program into FPGA cluster 2.

[0084] Step 204: Build an interface calculation module. Figure 3 The constant voltage station shown is of bus voltage control type, and the interface of the controlled voltage source is selected.

[0085] Step 205: Input the parameters of the system to be simulated, set the initial simulation time t=0, the simulation step length Δt of the EMT calculation module, the simulation step length ΔT of the DP calculation module, and the total simulation time T.

[0086] Step 206: Initialize interface module parameters and determine whether the system selects serial timing simulation or parallel timing simulation.

[0087] Step 207: Update the simulation time t=t+ΔT.

[0088] Step 208: The EMT calculation module completes n single-step simulations. After each simulation, no data interaction is performed, and the dynamic phasor interaction value uses the value of the first single-step simulation, while the initial values ​​of other state quantities need to be updated after each simulation.

[0089] Step 209: The DP calculation module completes a single-step simulation.

[0090] Step 2010: Determine whether the simulation is finished, if t<T, proceed to step 2011, otherwise proceed to step 2014.

[0091] Step 2011: The EMT calculation module and the DP calculation module transmit the interaction value at time t to the interface module.

[0092] Step 2012: The interface calculation module analyzes the interactive data transmitted by the EMT subsystem, generates instantaneous values, and transmits them to the DP calculation module; analyzes the interactive data transmitted by the DP subsystem, extracts dynamic phasor values, and transmits them to the EMT calculation module.

[0093] Step 2013: After the states and control matrices of the EMT calculation module and the DP calculation module are updated, return to step 206.

[0094] Step 2014: Output the results and the simulation ends.

[0095] The solution of this embodiment can be applied to the platform of dynamic phasor (DP)-electromagnetic transient (EMT) hybrid simulation of DC power system, using dynamic phasor modeling to process the non-concerned parts of the DC power system to be simulated, to ensure the high efficiency of the simulation; using electromagnetic transient modeling to process the concerned parts of the DC power system to be simulated, to ensure the accuracy of the simulation; using multi-block FPGA to realize interface data interaction and serial and parallel timing hybrid simulation, to ensure the high efficiency of the simulation. The existing electromagnetic transient simulation platform can be used to build a dynamic phasor-electromagnetic transient hybrid simulation heterogeneous platform, balancing the accuracy and speed of power system simulation. The proposed dynamic phasor-electromagnetic transient hybrid simulation has little hardware restrictions on the simulation equipment, and can realize the simulation of large-scale AC and DC systems; it can flexibly realize the modification of the hybrid simulation interface mode, and the modification and upgrade of the hybrid simulation.

[0096] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.< / xy> < / x> < / x> < / x>

Claims

1. A method for analyzing the dynamic characteristics of a DC power system based on mixed time scale modeling, characterized in that: include: S1. Establish the EMT subsystem and DP subsystem of the DC power system; S2, import the established EMT subsystem into FPGA1, and import the established DP subsystem into FPGA2; S3, establish an interface computing module according to the external characteristics of the EMT subsystem and the DP subsystem, and deploy it on FPGA3, wherein the FPGA3 is used for data interaction between the EMT computing module and the DP computing module; S4. After initialization, the EMT subsystem performs n single-step analysis and the DP subsystem performs one single-step analysis until the interaction time is reached; S5, outputting the analysis result to the terminal device; The state equation of the EMT subsystem is expressed as: Among them, r D is the real-time interaction amount of the DP subsystem, represents the differential term of the state variable of the EMT subsystem, A E represents the EMT subsystem state variable matrix, x E Indicates the state variable of the EMT subsystem, B E represents the EMT subsystem control variable matrix, u represents the EMT subsystem control variable, C E-D represents the interaction matrix of EMT subsystem, subscript E represents EMT subsystem, and subscript D represents DP subsystem; The state equation of the DP subsystem is expressed as: r E is the real-time interaction quantity of the EMT subsystem, k represents the dynamic phasor order, represents the differential term of the DP subsystem state variable, x D represents the DP subsystem state variable, j represents the imaginary unit, ω s =2π / T, T represents the fundamental wave period, A D represents the DP subsystem state variable matrix, B D represents the DP subsystem control variable matrix, u D Represents the DP subsystem control variable, operator <x> k represents the k-order dynamic phasor of the corresponding variable;< / x> Also includes: The dynamic process of the DP subsystem is split into real and imaginary parts, where the real and imaginary parts are: R represents the real part, I represents the imaginary part, represents the real part matrix of the DP subsystem state variables, represents the imaginary part matrix of the DP subsystem state variables, represents the real part matrix of the DP subsystem control variables, represents the imaginary matrix of the DP subsystem control variables, represents the real part matrix of the interaction quantity of the DP subsystem, represents the imaginary part matrix of the interaction quantity of the DP subsystem, represents the real part of the real-time interaction quantity of the EMT subsystem, Represents the imaginary part of the real-time interaction quantity of the EMT subsystem, represents the real part of the DP subsystem state variable, Represents the imaginary part of the DP subsystem state variable.

2. The method for analyzing dynamic characteristics of a DC power system based on mixed time scale modeling according to claim 1 is characterized in that: In the process of using FPGA3 to perform data interaction between the EMT computing module and the DP computing module, the interface mechanisms used include: Extracting a dynamic phasor value from the instantaneous value of the interactive quantity output by the EMT subsystem; Generate an instantaneous value of the interactive quantity by using the interactive quantity in the form of a dynamic phasor output by the DP subsystem; Among them, a controlled voltage source and a controlled current source are used as interface circuits for single-step solution of the EMT subsystem and the DP subsystem, and the interaction quantity is used as the controlled source amplitude.

3. The method for analyzing dynamic characteristics of a DC power system based on mixed time scale modeling according to claim 1 is characterized in that: In step S4, the initialization process includes: The EMT calculation module of the EMT subsystem, the DP calculation module of the DP subsystem and the interface calculation module are initialized, and the initialization processing includes: the time of the three modules is synchronized and the initial time is t=t0, the simulation step length Δt of the EMT subsystem, the simulation step length ΔT=nΔt of the DP subsystem, the total simulation time T, the system parameters of the EMT calculation module and the DP calculation module, wherein t0 represents the initial time which is generally 0, and Δt represents the simulation step length of the EMT subsystem.

4. The method for analyzing dynamic characteristics of a DC power system based on mixed time scale modeling according to claim 1 or 3, characterized in that: In step S4, the DP subsystem performs a single-step analysis, including: At time t1, the interactive quantity in the form of dynamic phasor output by the DP subsystem generates an instantaneous value sequence through the interface and is transmitted to the EMT subsystem; The EMT subsystem reads the interaction quantity from the instantaneous value sequence and sets the interface circuit controlled source, and then performs analysis according to the electromagnetic transient step length until time t2; According to the analysis results obtained by the EMT subsystem, the instantaneous value sequence is updated, the dynamic phasor value of the interaction quantity is extracted through the hybrid simulation interface, and is passed to the DP subsystem; The DP subsystem executes to time t2, and if the interaction interval is consistent with the DP subsystem simulation step size, only one iteration is performed.

5. The method for analyzing dynamic characteristics of a DC power system based on mixed time scale modeling according to claim 1 or 3, characterized in that: In step S4, the EMT subsystem performs n single-step length analyses, including: At time t1, the interactive quantity in the form of dynamic phasor output by the DP subsystem generates an instantaneous value through the hybrid simulation interface and then passes it to the EMT subsystem; the EMT subsystem uses the instantaneous value sequence to extract the dynamic phasor value of the interactive quantity through the interface and passes it to the DP subsystem.

6. The method for analyzing dynamic characteristics of a DC power system based on mixed time scale modeling according to claim 5 is characterized in that: When serial timing is used, it includes: At time t1, the dynamic phasor value of the DP subsystem interaction quantity <r D > k Generate instantaneous value sequence r through hybrid simulation interface D,n = {r D,n (t),…r D,n (t+(m-1)Δt)}, it is passed to the EMT subsystem; The EMT subsystem is derived from the instantaneous value sequence of the interaction quantity r D In the process, the interaction quantities are read in turn and the controlled source of the interface circuit is set. The simulation is performed m steps according to the electromagnetic transient step length Δt until the moment t2; Based on the simulation results of the EMT subsystem (t1, t2], the instantaneous value sequence of the interaction quantity in the period [t2-T, t2] is updated, and the dynamic phasor value of the interaction quantity is extracted through the hybrid simulation interface. <r E > k , and passed to the DP subsystem for simulation at (t1, t2]; The DP subsystem executes with a simulation step size of ΔT until time t2. If the interaction interval is consistent with the DP subsystem simulation step size, only one iteration is performed.

7. The method for analyzing dynamic characteristics of a DC power system based on mixed time scale modeling according to claim 5 is characterized in that: When using parallel sequential processing, it includes: At time t1, the dynamic phasor value of the DP subsystem interaction quantity <r D > k Generate instantaneous value sequence r through hybrid simulation interface D,n = {r D,n (t),…r D,n (t+(m-1)Δt)}, and then pass it to the EMT subsystem; at the same time, the EMT subsystem uses the instantaneous value sequence of the interaction quantity in the period [t1-T, t1] to extract the dynamic phasor value of the interaction quantity through the interface <r E > k And pass it to the DP subsystem; The EMT subsystem and DP subsystem execute simulation with step sizes Δt and ΔT respectively until time t2, and the DP subsystem updates the instantaneous value sequence of the interaction quantity to [t2-T, t2].

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