New power system dynamic simulation method and system based on improved inverter model
By improving the inverter model, constructing a state-space model of detailed control links, and performing synchronous calculations with a unified time step, the problems of low inverter modeling accuracy and timing asynchrony were solved, and high-precision dynamic simulation of new power systems was realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG UNIV
- Filing Date
- 2026-04-27
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies for new power systems, inverter modeling accuracy is low, dynamic response is inaccurate, and timing is out of sync, resulting in large deviations between simulation results and actual operating conditions, making it difficult to achieve high-precision dynamic simulation at the system level.
An improved inverter model is adopted, matching PQ and PV bus models for grid-connected and grid-connected inverters respectively. A state-space model containing detailed control loops such as phase-locked loop, power loop, and current loop is constructed. Synchronous simulation between AC side and inverter side is achieved by unifying time step and data interaction calculation.
It improves simulation accuracy, solves the problems of low inverter modeling accuracy and timing asynchrony, and realizes high-precision dynamic simulation analysis of power systems with a high proportion of inverters connected to the power system.
Smart Images
Figure CN122118909A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of novel power system stability analysis technology, and in particular to a novel power system dynamic simulation method and system based on an improved inverter model. Background Technology
[0002] With the continuous advancement of the construction of new power systems based on new energy sources, power electronic inverters are being widely integrated into distributed power sources, new energy power generation, and energy storage, resulting in a high proportion of power electronics in the power grid. Currently, dynamic simulation analysis of new power systems with a high proportion of inverters mainly adopts three technical approaches: electromechanical transient simulation, electromagnetic transient simulation, and hybrid simulation combining both.
[0003] In traditional electromechanical transient simulations, the system-side simulation timescale is typically on the millisecond level, while the inverter model uses microsecond-level detailed control loop modeling. This inconsistency in time scales leads to a mismatch in the solutions to the differential equations, and the use of a detailed inverter model results in the curse of system dimensionality, increasing the difficulty of solving the problem. Therefore, existing electromechanical transient simulations often employ simplified steady-state or quasi-steady-state inverter models. However, this neglects detailed control strategies such as the inverter's dual-loop and phase-locked loop (PLL) systems, resulting in significant deviations between simulation results and actual operating conditions, making it difficult to achieve high-precision dynamic simulation at the system level.
[0004] While existing electromagnetic transient simulations can provide detailed switching-level modeling of inverters with high accuracy, the models are complex, computationally intensive, and time-consuming. This limits their applicability to device-level or small-scale local systems, making it difficult to support system-level dynamic simulations of distribution networks or areas with numerous inverters. Furthermore, hybrid simulations, which combine electromechanical transient simulations on the system side with localized electromagnetic transient simulations on the inverter side, can balance accuracy and efficiency, but inherent drawbacks include timing asynchrony, non-real-time data exchange, and complex interface coupling, hindering the safety and stability analysis of new power systems. Summary of the Invention
[0005] To address the shortcomings of the existing technologies, this invention provides a novel dynamic simulation method and system for power systems based on an improved inverter model. This method solves problems such as low inverter modeling accuracy, inaccurate dynamic response, and timing asynchrony in traditional simulation methods, enabling high-precision dynamic simulation analysis at the system level for power systems with a high proportion of inverters connected.
[0006] In a first aspect, the present invention provides a novel dynamic simulation method for power systems based on an improved inverter model.
[0007] A novel dynamic simulation method for power systems based on an improved inverter model includes: Obtain the topology information of the new power system and the control type and installation node of the inverter installed inside it, and construct the node admittance matrix of the AC side system; Based on the control type of the inverter, an appropriate bus model is added to its installation node for interconnection between the inverter and the AC side system, and an inverter state space model containing complete control loops is constructed. Based on the nodal admittance matrix, the Newton-Raphson polar coordinate method is used to perform power flow calculation on the AC side system, and the power flow calculation results are used as the initial values for electromechanical transient simulation calculation. Separate time-domain simulation calculation methods are set for the electromechanical transients of the AC side system and the inverter side model, respectively. The simulation time and step size are unified. Based on the initial values, the AC side system and inverter side models are solved iteratively until the simulation time ends, and the dynamic simulation calculation results of the key parameters of the inverter are output.
[0008] A further technical solution is that the new power system topology information includes key parameter information of the generators, transformers, lines, busbars and loads covered by the distribution area.
[0009] A further technical solution involves adding a suitable bus model to the AC side installation node of the inverter, based on the inverter's control type. This includes: If the inverter is a grid-connected inverter, a PQ bus model is added at the corresponding installation bus node, and its mathematical constraints are as follows: ; If the inverter is a grid-type inverter, a new PV bus model is added at the corresponding installation bus node, and its mathematical constraints are as follows: ; In the above formula, P inv To output active power to the inverter, P ref inv The active power reference value given to the inverter power loop. Q inv To output reactive power to the inverter, Q ref inv The reactive power reference value given to the inverter power loop. U inv This represents the bus voltage amplitude at the inverter connection point. U ref inv This is the voltage reference value given to the inverter voltage loop.
[0010] A further technical solution employs a state-space equation modeling method, incorporating the complete control loops of the inverter—phase-locked loop, power outer loop, and current inner loop—into the model. This constructs time-domain state-space models for both grid-connected and grid-connected inverters, reflecting the dynamic characteristics of the inverter during power system operation. The general state-space expression of the inverter is as follows: ; In the above formula, the superscript inv represents the inverter, and x is the state variable matrix. Let y be the first derivative of the state variable matrix, u be the input variable matrix, and y be the output variable matrix; This is the system state matrix of the inverter. This is the input matrix of the inverter. This is the output matrix of the inverter. This is the direct transfer matrix of the inverter.
[0011] A further technical solution is to use the power flow calculation results as the initial values for electromechanical transient simulation calculations, including the voltage amplitude, phase angle, active power, and reactive power of each bus node; The electromechanical transient solution of the AC side system is set to use the NR iteration combined with the implicit trapezoidal method suitable for DAE, and the solution of the inverter side model is set to use the RK method. The simulation time and step size are uniformly set for both sides. According to the initial values, the AC side system and the inverter side model are solved iteratively according to the set step size. In each iteration step, the mathematical models of the two sides interact and calculate data until the simulation time ends, and the dynamic simulation calculation results of the key inverter parameters are output. The key inverter parameters include active power time series, reactive power time series, and current component series.
[0012] A further technical solution involves the iterative solution process for the AC-side system and inverter-side models as follows: The AC side system calculates according to a set step size and outputs the active power, reactive power, voltage amplitude, and phase angle at the current moment to the inverter side; The inverter side processes the variables input from the AC side to construct the input variable matrix of the inverter side state-space model; The input variable matrix is substituted into the inverter state-space model for solution to obtain the output matrix. The active and reactive power output of the inverter at the current moment are obtained through the instantaneous power calculation formula and output to the AC side system for the next long solution. The calculation process on the AC side and the inverter side is continuously iterated until the simulation time ends, completing the full-time dynamic simulation calculation and outputting the calculation results.
[0013] Secondly, this invention provides a novel dynamic simulation system for power systems based on an improved inverter model.
[0014] A novel power system dynamic simulation system based on an improved inverter model includes: The data acquisition module is used to acquire the topology information of the new power system and the control type and installation node of the inverters installed inside it; The model building module is used to construct the node admittance matrix of the AC side system based on the topology information; according to the control type of the inverter, an appropriate bus model is added to its installation node for the interconnection between the inverter and the AC side system, and at the same time, an inverter state space model containing complete control loops is constructed. The dynamic simulation module is used to perform power flow calculations on the AC side system based on the nodal admittance matrix and the Newton-Raphson polar coordinate method. The power flow calculation results are used as the initial values for electromechanical transient simulation calculations. The time-domain simulation calculation methods for the electromechanical transients of the AC side system and the inverter side model are set separately, and the simulation time and step size are unified. Based on the initial values, the AC side system and inverter side models are iteratively solved until the simulation time ends, and the dynamic simulation calculation results of the key parameters of the inverter are output.
[0015] Thirdly, the present invention also provides an electronic device, comprising: a memory for storing executable instructions; and a processor for implementing the novel power system dynamic simulation method based on an improved inverter model when executing the executable instructions stored in the memory.
[0016] Fourthly, the present invention also provides a computer-readable storage medium storing executable instructions for causing a processor to execute the executable instructions to implement the above-described novel power system dynamic simulation method based on an improved inverter model.
[0017] Fifthly, the present invention also provides a computer program product comprising executable instructions stored in a computer-readable storage medium; wherein, when the processor of an electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the aforementioned novel power system dynamic simulation method based on an improved inverter model is implemented.
[0018] The above one or more technical solutions have the following beneficial effects: This invention provides a novel dynamic simulation method and system for power systems based on an improved inverter model. Addressing the shortcomings of current simulation methods in accurately reflecting the actual operating conditions of new power systems with a large number of inverters, this invention achieves precise interconnection by matching corresponding bus models to grid-connected and grid-linked inverters. It constructs a state-space mathematical model considering detailed control strategies such as inverter power loops, current loops, and phase-locked loops. Through synchronous calculations with a unified time step and interactive calculations of electrical data between the AC and inverter side models, dynamic simulation analysis of new power systems with a high proportion of inverters is achieved. This solves problems such as low inverter modeling accuracy, inaccurate dynamic response, and timing asynchrony in traditional simulation methods. This invention significantly improves simulation accuracy and provides support for the stability analysis of new power systems.
[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0021] Figure 1 This is a flowchart of a novel power system dynamic simulation method based on an improved inverter model, as described in Embodiment 1 of the present invention. Detailed Implementation
[0022] It should be noted that the following detailed descriptions are exemplary and are intended only to describe specific embodiments and to provide further explanation of the invention, and are not intended to limit the scope of exemplary embodiments of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0023] As pointed out in the background section, for dynamic simulation analysis of new power systems with a high proportion of inverters, existing electromechanical transient simulation methods oversimplify inverter control strategies and fail to consider detailed control strategies such as the inverter's power loop, current loop, and phase-locked loop. This makes it difficult to realistically depict the inverter's dynamic response characteristics under voltage fluctuations and power disturbances, resulting in significant deviations between the electromechanical transient simulation results and actual operating conditions, thus failing to meet the dynamic operation analysis requirements of new power systems. Existing electromagnetic transient simulation methods provide detailed inverter modeling, but the complexity of the models leads to excessively long simulation times. Existing combined electromechanical and electromagnetic transient calculation methods suffer from timing asynchrony and non-real-time data interaction. Especially in the scenario of low-voltage distribution networks in transformer substations, the diverse inverter control types and complex topologies make it difficult for the aforementioned existing simulation methods to achieve high-precision system-level dynamic simulation, severely restricting the planning, design, and stable operation analysis of new power systems.
[0024] To address the aforementioned problems, this invention proposes a novel dynamic simulation method for power systems based on an improved inverter model. First, PQ and PV bus models are matched to grid-connected and grid-connected inverters respectively to achieve accurate interconnection. A detailed inverter model is then constructed, incorporating detailed control loops such as power loops, current loops, and phase-locked loops. Then, by unifying the time step and facilitating electrical data interaction between the AC-side system network and the inverter model, dynamic simulation analysis of novel power systems with a high proportion of inverters is achieved. Unlike traditional hybrid simulation methods that directly use the inverter's switching-level electromagnetic transient model, this invention models only the inverter control structure, transforming it into a state-space model adapted to electromechanical transients. The system side and inverter side are interconnected, using different solvers and interacting and solving data through a unified interface and time step. This achieves high-precision power system simulation considering detailed inverter control strategies, solving problems such as low inverter modeling accuracy, inaccurate dynamic response, and timing asynchrony in traditional simulation methods.
[0025] Example 1 This embodiment provides a novel dynamic simulation method for power systems based on an improved inverter model, such as... Figure 1 As shown, the specific steps include: Step S1: Obtain the topology information of the new power system and the control type and installation node of the inverter installed inside it, and construct the node admittance matrix of the AC side system.
[0026] In this embodiment, the power system topology information, i.e., the distribution area topology information, is first obtained. Specifically, this includes key parameters of the generators, transformers, lines, buses, and loads covered by the distribution area. Among these, the generator parameters include the generator's rated capacity S. GN Rated voltage U GN Inertial time constant TJ Damping coefficient Z, etc.; transformer parameters include rated turns ratio n, rated transformer capacity S. N Short-circuit voltage percentage u k Short-circuit loss P k No-load loss P0, etc.; line parameters include resistance R, reactance X, susceptance B, etc.; bus parameters include number, bus voltage U0, phase angle δ0, etc.; key load parameters include rated active power P. L Rated reactive power Q L It should be clarified that the key parameters of the above-mentioned components can be determined according to the actual power system topology, and are not intended as specific limitations of this embodiment.
[0027] Next, based on the key parameters obtained above, the nodal admittance matrix of the power system is constructed, which can be expressed as: ; In the above formula, Y bus Let be the nodal admittance matrix of the system, N be the number of bus nodes in the system, G be the conductance of the system, and B be the susceptance. Represents the set of real numbers. This represents an N×N matrix.
[0028] Meanwhile, considering that the interconnection method needs to be determined based on the dynamic characteristics of the inverter when connecting to the AC network, it is necessary to obtain and confirm the control type of the inverter in the distribution area and the bus nodes where they are installed. The inverter control types mainly include two types: grid-connected inverters and grid-connected inverters.
[0029] Step S2: Based on the control type of the inverter, add an appropriate bus model to its installation node for interconnection between the inverter and the AC side system, and at the same time construct an inverter state space model containing complete control links.
[0030] Step S2.1: Based on the control type of the inverter, add an adapted bus model to the installation bus node of its AC side system to achieve accurate matching between the inverter output characteristics and the AC network node characteristics.
[0031] Specifically, inverter control types include grid-following and grid-connected types. If the input inverter control type is a grid-following inverter, since it has current-source output characteristics and relies on grid voltage orientation to achieve power tracking, its output active and reactive power are controllable setpoints, perfectly matching the node characteristics of the PQ bus. Therefore, a new PQ bus model is added at the corresponding installation bus node, with the following mathematical constraints: ; In the above formula, the superscript inv indicates the inverter. P inv To output active power to the inverter,P ref inv The active power reference value given to the inverter power loop. Q inv To output reactive power to the inverter, Q ref inv This is the reactive power reference value given to the inverter power loop.
[0032] If the input inverter control type is a grid-type inverter, since the grid-type inverter has voltage source output characteristics and possesses independent voltage support capability, it can stabilize the voltage amplitude at the connection point and control the output active power, perfectly matching the node characteristics of the PV bus. Therefore, the mathematical constraints for adding a PV bus model at the corresponding installation bus node are: ; In the above formula, U inv This represents the bus voltage amplitude at the inverter connection point. U ref inv This is the voltage reference value given to the inverter voltage loop.
[0033] By distinguishing between grid-connected and grid-connected inverters and matching PQ / PV bus models accordingly, precise interconnection between the inverter and the AC system can be achieved, which can significantly improve the adaptability and accuracy of electromechanical transient simulation for dynamic calculation of high-proportion inverter grid-connected systems.
[0034] Step S2.2: Using the state-space equation modeling method, the complete control loops of the inverter, such as the phase-locked loop, power outer loop, and current inner loop, are incorporated into the modeling. Time-domain state-space models of grid-connected and grid-connected inverters are constructed respectively to reflect the dynamic characteristics of the inverter in the power system operation.
[0035] The general state-space representation of the inverter is as follows: ; In the above formula, the superscript inv represents the inverter, and x is the state variable matrix. y is the first derivative of the state variable matrix, and the "·" on this parameter indicates that the first derivative of the parameter is taken; u is the input variable matrix, and y is the output variable matrix; This is the system state matrix of the inverter. This is the input matrix of the inverter. This is the output matrix of the inverter. This is the direct transfer matrix of the inverter, which is set to zero by default.
[0036] Furthermore, taking a grid-connected inverter as an example, the phase-locked loop, power loop, and current loop control strategies of the grid-connected inverter are modeled using state-space equations, thereby fully reflecting the dynamic characteristics of the inverter during system operation. The control strategies are modeled as follows: (1) In the synchronous rotating coordinate system, the state equation of the phase-locked loop PI control structure is: ; In the above formula, x pll For the integral state variable of the phase-locked loop PI controller, u q This represents the q-axis component of the grid voltage. oh ac The system's rated angular frequency, k p,pll , k i,pll For the proportional and integral coefficients of the phase-locked loop PI controller, oh pll This is the output angular frequency of the phase-locked loop. i pll The output phase angle of the phase-locked loop is indicated by the "·" symbol on the parameter, which represents the first derivative of the parameter.
[0037] (2) The state equation of the power outer loop control structure is: ; In the above formula, Active power This is a reference value for active power. P ref inv The active power reference value given to the inverter power loop. Reactive power This is a reference value for reactive power. x p , x q These are the integral state variables of the active and reactive power loop PI controller. k p,p , k i,p These are the proportional and integral coefficients of the active power loop PI. k p,q , k i,q The proportional and integral coefficients of the reactive power loop PI. i d,ref , i q,ref These are the reference values for the d-axis and q-axis currents of the inner current loop.
[0038] (3) The state equation of the current inner loop control structure is: ; In the above formula, , These are the d-axis and q-axis current components of the inner current loop. x id , x iq For the integral state variables of the d-axis and q-axis current loop PI controller, i d,ref , i q,ref These are the reference values for the d-axis and q-axis currents of the inner current loop; u q , These are the q-axis and d-axis components of the grid voltage. R f , L f Here are the equivalent resistance and inductance values of the filter inductor. u d inv , u q inv These are the d-axis and q-axis components of the inverter bridge arm output voltage. k p,id , k i,id The proportional and integral coefficients of the d-axis current loop PI. k p,iq , k i,iq These are the proportional and integral coefficients of the q-axis current loop PI.
[0039] (4) The state-space input-output model of the grid-connected inverter is shown in the following equation: ; In the above formula, y is the inverter-side output variable matrix, and u is the inverter-side input variable matrix. The input-output control matrix of the inverter is expressed as follows: ; in, It is an identity matrix.
[0040] Step S3: Based on the nodal admittance matrix Y bus The Newton-Raphson polar coordinate method was used to perform power flow calculations on the AC side system, and the results of the power flow calculations were used as the initial values for electromechanical transient simulation calculations.
[0041] This step provides steady-state initial values for electromechanical transient simulation, solves the initial value assignment problem for solving differential equations, and ensures that transient simulation iterates from the system's steady-state operating condition. After the power flow calculation of the AC system is completed, the voltage amplitude of each bus node is... u 0 ac Phase angle a 0 ac Active power P 0 ac reactive power Q 0 ac As the initial value for dynamic calculation.
[0042] Step S4: Set the time-domain simulation calculation method for the electromechanical transients of the AC side system and the inverter side model, unify the simulation time and step size, and perform iterative solution of the AC side system and inverter side model based on the initial values until the simulation time ends, and output the dynamic simulation calculation results of the key parameters of the inverter.
[0043] In this embodiment, the inverter-side model is solved using the RK (Runge-Kutta) method, while the electromechanical transients of the AC-side system are solved using the NR (Newton-Raphson) iterative method combined with the implicit trapezoidal rule, suitable for DAEs (Differential-Algebraic Equations). Simulation times are uniformly set for both sides. T and step size Δ t Based on initial values, the AC-side system and inverter-side models are iteratively solved at set step sizes. Within each iteration step, the two mathematical models interact and perform calculations until the simulation ends, outputting dynamic simulation results for key parameters such as the inverter's active power time series, reactive power time series, and current component series. Through this unified step size, bidirectional data interaction, and iterative solution, the electromechanical transients of the AC grid and the detailed control model of the inverter can be synchronously calculated in a closed loop within the same time axis and solution framework. This solves the timing misalignment and computational instability problems inherent in traditional simulations, enabling system-level accurate power system simulation that considers the detailed control strategy of the inverter.
[0044] Furthermore, the above iterative solution process is as follows: Step S4.1: The AC side system begins calculation. After each simulation step is completed, the current value is output. t k Active power output of the AC side system at this time P pf,k ac reactive power Q pf,k ac Voltage amplitude upf,k ac and phase angle a pf,k ac To the inverter side. Among them, t k =k Δ t k=0,1,2… K , representing the time corresponding to the k-th step size; K = T / Δ t , which represents the number of simulation steps contained in the entire simulation time T.
[0045] Step S4.2: The inverter side processes the variables input from the AC side to construct the input variable matrix u of the inverter side mathematical model.
[0046] Specifically, voltage amplitude u pf,k ac and phase angle a pf,k ac It needs to undergo a dq transformation, as shown below: ; ; In the above formula, u d,k ac For the grid voltage at t The d-axis component at time t. u q,k ac For the grid voltage t The q-axis component at time t. oh ac The system angular frequency, i pll,k for t k The AC side phase output of the phase-locked loop at any given time.
[0047] Furthermore, the expressions for each input element within the input variable matrix u of the inverter-side mathematical model are as follows: ; In the above formula, P ref inv Provide active power to the inverter's power loop. Q ref inv Provide reactive power to the inverter's power loop.
[0048] Step S4.3: Substitute the input variable matrix into the inverter state-space model for solution. The obtained calculation result is the output matrix y of the model. Then, obtain the active and reactive power output of the inverter at the current moment through the instantaneous power calculation formula, and output it to the AC side for the next step of long-term solution.
[0049] The expressions for each element of the output matrix of the inverter model are as follows: ; In the above formula, i d,k inv For the inverter current inner loop in t k The d-axis current output at any given time. i q,k inv For the inverter current inner loop in t k The q-axis current output at any given time.
[0050] Inverter at all times t k The expressions for the output active power and reactive power are: ; In the above formula, P k inv for t k The active power output by the inverter to the AC side at any given time. Q k inv for t k The reactive power output of the inverter to the AC side at any given time.
[0051] Step S4.4: Continuously iterate the above calculation process for the AC test and inverter side until the simulation time ends, complete the full-time dynamic simulation calculation, and output the calculation results; otherwise, repeat steps S4.1 to S4.3 for each simulation step until the simulation time is set.
[0052] Specifically, the simulation ends, that is... t k ≥ T Perform simulation termination verification and output simulation results, i.e., output inverter active power time series. P inv Reactive power time series Q inv Current component sequence I d , I qThe dynamic simulation calculation results of key parameters, among which P inv =[ P 0 inv , P 1 inv , …, P K inv ], Q inv =[ Q 0 inv , Q 1 inv , …, Q K inv Otherwise, let k = k + 1, and continue the iterative calculation of the next simulation step. Repeat steps S4.1 to S4.3 for each simulation step until the simulation ends.
[0053] By incorporating the detailed control strategy of the inverter into the electromechanical transient calculation of the system in the form of state-space equations, the problem of oversimplification of the inverter's dynamic characteristics by the traditional electromechanical transient model can be improved. This enables high-precision simulation of power systems with a high proportion of inverters connected to the system, and solves the problem that the simulation results of electromechanical transient calculations for systems with a large number of inverters connected to the system cannot truly reflect the actual operating conditions of the system.
[0054] Example 2 This embodiment provides a novel dynamic simulation system for power systems based on an improved inverter model, specifically including: The data acquisition module is used to acquire the topology information of the new power system and the control type and installation node of the inverters installed inside it; The model building module is used to construct the node admittance matrix of the AC side system based on the topology information; according to the control type of the inverter, an appropriate bus model is added to its installation node for the interconnection between the inverter and the AC side system, and at the same time, an inverter state space model containing complete control loops is constructed. The dynamic simulation module is used to perform power flow calculations on the AC side system based on the nodal admittance matrix and the Newton-Raphson polar coordinate method. The power flow calculation results are used as the initial values for electromechanical transient simulation calculations. The time-domain simulation calculation methods for the electromechanical transients of the AC side system and the inverter side model are set separately, and the simulation time and step size are unified. Based on the initial values, the AC side system and inverter side models are iteratively solved until the simulation time ends, and the dynamic simulation calculation results of the key parameters of the inverter are output.
[0055] Example 3 This embodiment provides an electronic device, including: a memory for storing executable instructions; and a processor for executing the executable instructions stored in the memory to implement the method provided in this embodiment.
[0056] Example 4 This embodiment also provides a computer-readable storage medium storing executable instructions, which, when executed by a processor, will cause the processor to execute the method described above in this embodiment.
[0057] Example 5 This embodiment provides a computer program product including executable instructions, which are computer instructions; the executable instructions are stored in a computer-readable storage medium. When the processor of an electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the electronic device performs the method described in this embodiment.
[0058] The steps and methods involved in Embodiments 2 to 5 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.
[0059] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.
[0060] The above description is only a preferred embodiment of the present invention. Although the specific implementation of the present invention has been described in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.
Claims
1. A novel dynamic simulation method for power systems based on an improved inverter model, characterized in that, include: Obtain the topology information of the new power system and the control type and installation node of the inverter installed inside it, and construct the node admittance matrix of the AC side system; Based on the control type of the inverter, an appropriate bus model is added to its installation node for interconnection between the inverter and the AC side system, and an inverter state space model containing complete control loops is constructed. Based on the nodal admittance matrix, the Newton-Raphson polar coordinate method is used to perform power flow calculation on the AC side system, and the power flow calculation results are used as the initial values for electromechanical transient simulation calculation. Separate time-domain simulation calculation methods are set for the electromechanical transients of the AC side system and the inverter side model, respectively. The simulation time and step size are unified. Based on the initial values, the AC side system and inverter side models are solved iteratively until the simulation time ends, and the dynamic simulation calculation results of the key parameters of the inverter are output.
2. The novel power system dynamic simulation method based on an improved inverter model as described in claim 1, characterized in that, The new power system topology information includes key parameter information of the generators, transformers, lines, buses and loads covered by the distribution area.
3. The novel power system dynamic simulation method based on an improved inverter model as described in claim 1, characterized in that, Based on the inverter's control type, an adapted bus model is added to its AC side installation node, including: If the inverter is a grid-connected inverter, a PQ bus model is added at the corresponding installation bus node, and its mathematical constraints are as follows: ； If the inverter is a grid-type inverter, a new PV bus model is added at the corresponding installation bus node, and its mathematical constraints are as follows: ； In the above formula, P inv To output active power to the inverter. P ref inv The active power reference value given to the inverter power loop. Q inv To output reactive power to the inverter, Q ref inv The reactive power reference value given to the inverter power loop. U inv This represents the bus voltage amplitude at the inverter connection point. U ref inv This is the voltage reference value given to the inverter voltage loop.
4. The novel power system dynamic simulation method based on an improved inverter model as described in claim 1, characterized in that, A state-space equation modeling method is adopted, incorporating the complete control loops of the inverter—phase-locked loop, power outer loop, and current inner loop—into the model to construct time-domain state-space models for grid-connected and grid-connected inverters, respectively, to reflect the dynamic characteristics of the inverter during power system operation. The general state-space expression form of the inverter is as follows: ； In the above formula, the superscript inv represents the inverter, and x is the state variable matrix. Let y be the first derivative of the state variable matrix, u be the input variable matrix, and y be the output variable matrix; This is the system state matrix of the inverter. This is the input matrix of the inverter. This is the output matrix of the inverter. This is the direct transfer matrix of the inverter.
5. The novel power system dynamic simulation method based on an improved inverter model as described in claim 1, characterized in that, The power flow calculation results are used as the initial values for electromechanical transient simulation calculations, including the voltage amplitude, phase angle, active power, and reactive power of each bus node; The electromechanical transient solution of the AC side system is set to use the NR iteration combined with the implicit trapezoidal method suitable for DAE, and the solution of the inverter side model is set to use the RK method. The simulation time and step size are uniformly set for both sides. According to the initial values, the AC side system and the inverter side model are solved iteratively according to the set step size. In each iteration step, the mathematical models of the two sides interact and calculate data until the simulation time ends, and the dynamic simulation calculation results of the key inverter parameters are output. The key inverter parameters include active power time series, reactive power time series, and current component series.
6. The novel power system dynamic simulation method based on an improved inverter model as described in claim 5, characterized in that, The iterative solution process for the AC-side system and inverter-side models is as follows: The AC side system calculates according to a set step size and outputs the active power, reactive power, voltage amplitude, and phase angle at the current moment to the inverter side; The inverter side processes the variables input from the AC side to construct the input variable matrix of the inverter side state-space model; The input variable matrix is substituted into the inverter state-space model for solution to obtain the output matrix. The active and reactive power output of the inverter at the current moment are obtained through the instantaneous power calculation formula and output to the AC side system for the next long solution. The calculation process on the AC side and the inverter side is continuously iterated until the simulation time ends, completing the full-time dynamic simulation calculation and outputting the calculation results.
7. A novel dynamic simulation system for power systems based on an improved inverter model, characterized in that, include: The data acquisition module is used to acquire the topology information of the new power system and the control type and installation node of the inverters installed inside it; The model building module is used to construct the node admittance matrix of the AC side system based on the topology information; according to the control type of the inverter, an appropriate bus model is added to its installation node for the interconnection between the inverter and the AC side system, and at the same time, an inverter state space model containing complete control loops is constructed. The dynamic simulation module is used to perform power flow calculations on the AC side system based on the nodal admittance matrix and the Newton-Raphson polar coordinate method, and the power flow calculation results are used as the initial values for electromechanical transient simulation calculations. Separate time-domain simulation calculation methods are set for the electromechanical transients of the AC side system and the inverter side model, respectively. The simulation time and step size are unified. Based on the initial values, the AC side system and inverter side models are solved iteratively until the simulation time ends, and the dynamic simulation calculation results of the key parameters of the inverter are output.
8. An electronic device, characterized in that, include: Memory, used to store executable instructions; The processor, when executing executable instructions stored in the memory, implements the novel power system dynamic simulation method based on an improved inverter model as described in any one of claims 1-6.
9. A computer-readable storage medium, characterized in that, The device stores executable instructions that, when executed by a processor, implement the novel power system dynamic simulation method based on an improved inverter model as described in any one of claims 1-6.
10. A computer program product, characterized in that, The computer program product includes executable instructions stored in a computer-readable storage medium; When the processor of the electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, it implements the novel power system dynamic simulation method based on an improved inverter model as described in any one of claims 1-6.