Numerical integration methods, systems, apparatuses, and media for power electronic circuit simulation

Abstract

The application provides a numerical integration method, system, device and medium for power electronic circuit simulation, aiming at the technical problems of large calculation amount of implicit method and numerical divergence of ordinary explicit method under rigid condition, and the main points of the scheme include: representing the AC side of the switching bridge arm in the power electronic circuit as an equivalent controlled voltage source and the DC side as an equivalent controlled current source, and constructing a differential algebraic equation; eliminating redundant quantities subjected to constraint domination through circuit topology analysis, and converting the equation into an equivalent ordinary differential equation; dividing the state quantities into two groups, obtaining the current switching signal and the state quantity of the current time step in the simulation time stepping process, updating the first group of state quantities to the next time step based on the current time step input by using explicit numerical integration, and updating the second group of state quantities to the next time step based on the updated value and the latest switching signal by using explicit numerical integration, so as to realize staggered updating. The application is mainly used for numerical solution and real-time simulation of the power electronic circuit.

Description

Technical Field

[0001] This invention relates to the field of numerical simulation technology for power electronic circuits, and in particular to a numerical integration method, system, device, and medium for power electronic circuit simulation. Background Technology

[0002] In power electronic circuits, the frequent switching of switching devices causes the circuit to exhibit a time-varying topology, and the parameter differences of energy storage components such as inductors and capacitors result in highly rigid circuit equations. These characteristics require numerical solution methods to simultaneously consider numerical stability, convergence, and computational efficiency. Furthermore, real-time simulation scenarios further demand that simulation algorithms have fixed step sizes and deterministic computational delays to adapt to the computing architecture of hardware platforms such as FPGAs.

[0003] In existing technologies, implicit numerical integration methods such as the trapezoidal rule and backward Euler method are commonly used to improve numerical stability and convergence. Implicit methods require solving a system of linear algebraic equations at each simulation time step. When the circuit contains nonlinear components or undergoes switching states, iterative solutions may also be necessary. While these methods offer good numerical stability, the computational cost per step is variable, and the computational complexity is difficult to determine, making them unsuitable for implementing real-time simulations with deterministic time delays on hardware platforms such as FPGAs.

[0004] On the other hand, explicit numerical integration methods such as the forward Euler method have low computational cost per step, simple algorithm structure, and no need to solve a system of equations, making them naturally suitable for hardware parallel implementation and deterministic computation. However, the stable step size of explicit methods is limited by the rigidity of the circuit. For power electronic circuits containing high-frequency resonant modes, a slightly larger step size may cause numerical oscillations or divergence, making it difficult to ensure numerical stability while meeting the step size requirements of real-time simulation. Summary of the Invention

[0005] This invention provides a numerical integration method, system, device, and medium for power electronic circuit simulation. It addresses the problems of existing implicit numerical integration methods being unsuitable for real-time simulation and FPGA hardware implementation due to the need to solve a system of equations and the variable amount of computation, while existing explicit numerical integration methods are limited in stable step size under the strong rigidity of power electronic circuits and cannot simultaneously achieve numerical convergence and deterministic computational complexity.

[0006] The core technology of this invention is to transform the power electronic circuit containing the switch bridge arm into a steady system by modeling the equivalent controlled source, to reduce the index of the differential algebraic equation into an ordinary differential equation by eliminating redundancy through topological analysis, and to solve the two sets of state variables in the ordinary differential equation by adopting an explicit numerical integration scheme with staggered progression by drawing on the idea of ​​symplectic integral. Thus, the numerical convergence close to that of the implicit method is achieved with the deterministic computational complexity of the explicit method.

[0007] In a first aspect, the present invention provides a numerical integration method for power electronic circuit simulation, the method comprising the following steps:

[0008] Equivalent modeling is performed on the switching bridge arm in the power electronic circuit, and the switching bridge arm is represented as an equivalent controlled source, where the AC side of the switching bridge arm is represented as an equivalent controlled voltage source and the DC side of the switching bridge arm is represented as an equivalent controlled current source. System equations describing the dynamic behavior of power electronic circuits are constructed based on equivalent modeling and circuit connection relationships. Analyze the system equations. If there are redundant quantities governed by circuit constraints, eliminate the redundant quantities and transform the system equations into equivalent ordinary differential equations. When the system equations do not contain redundant quantities governed by circuit constraints, directly express the system equations as ordinary differential equations. The state variables in the ordinary differential equation are divided into the first group of state variables and the second group of state variables. During the simulation time step progression, the switching signal and the state variables of the current time step are acquired. The value of the equivalent controlled source of the current time step is calculated through the coupling relationship of the switching signal. The first set of state variables is updated to the next time step based on the value of the equivalent controlled source of the current time step and the state variables of the current time step using an explicit numerical integration method. Based on the updated first set of state variables, the second set of state variables is updated to the next time step using an explicit numerical integration method to achieve the interleaved update of the two sets of state variables.

[0009] Furthermore, the switching signal coupling relationship includes: The value of the equivalent controlled voltage source is determined by the coupling of the switching signal of the switch arm with the DC side voltage of the switch arm; the value of the equivalent controlled current source is determined by the coupling of the switching signal of the switch arm with the AC side current of the switch arm.

[0010] Furthermore, the system equations are analyzed. If there are redundant quantities governed by circuit constraints, these redundant quantities are eliminated, transforming the system equations into equivalent ordinary differential equations. This process includes: Identify the loops formed by capacitors and voltage sources in power electronic circuits, and determine the redundant capacitor voltages and / or node voltages governed by voltage constraints; Identify cut sets formed by inductors and current sources in power electronic circuits, and determine redundant inductor currents and / or branch currents dominated by current constraints. Redundant capacitor voltage, node voltage, redundant inductor current or branch current are used as redundancy quantities, and quantities other than redundancy quantities that can characterize the dynamic degrees of freedom of power electronic circuits are selected as state quantities. Based on circuit constraints, redundancy is expressed as a functional expression of state variables, and the functional expression is substituted back into the original differential algebraic equation to generate an equivalent ordinary differential equation.

[0011] Furthermore, state quantities are circuit quantities with physical meaning, including inductor current, capacitor voltage, inductor flux linkage, and capacitor charge.

[0012] Furthermore, the grouping method for the first group of state variables and the second group of state variables adopts one of the following combinations: (1) The first set of state variables is inductor current or inductor flux linkage, and the second set of state variables is capacitor voltage or capacitor charge. (2) The first set of state variables is capacitor voltage or capacitor charge, and the second set of state variables is inductor current or inductor flux linkage.

[0013] Furthermore, based on the updated first set of state variables, the process of updating the second set of state variables to the next time step using an explicit numerical integration method includes: Keeping the value of the equivalent controlled source unchanged at the current time step, the second set of state variables updated to the next time step is calculated by combining the first set of state variables updated to the next time step and the second set of state variables at the current time step using an explicit numerical integration method.

[0014] Furthermore, based on the updated first set of state variables, the process of updating the second set of state variables to the next time step using an explicit numerical integration method includes: Based on the first set of state variables updated to the next time step and the second set of state variables in the current time step, the value of the equivalent controlled source is recalculated through the coupling relationship of the switching signals. Combining the first set of state variables updated to the next time step and the second set of state variables in the current time step, the second set of state variables updated to the next time step is calculated using an explicit numerical integration method.

[0015] Furthermore, explicit numerical integration methods include direct explicit numerical integration methods and / or explicit recursive integration methods obtained by explicitening implicit numerical integration schemes; explicitening includes performing algebraic transformations on implicit numerical integration schemes to obtain explicit recursive calculation formulas for the state variables of the next time step with respect to the state variables of the current time step; algebraic transformations include one or more of rearranging terms, elimination, matrix inversion, or matrix decomposition.

[0016] Secondly, the present invention provides a numerical integration system for power electronic circuit simulation, comprising: The equivalent modeling module is used to perform equivalent modeling of the switching bridge arm in the power electronic circuit, and to represent the switching bridge arm as an equivalent controlled source, wherein the AC side of the switching bridge arm is represented as an equivalent controlled voltage source and the DC side of the switching bridge arm is represented as an equivalent controlled current source. The equation construction module is used to construct system equations describing the dynamic behavior of the power electronic circuit based on equivalent modeling and circuit connection relationships. The equation transformation module is used to analyze the system equations. If there are redundant quantities governed by circuit constraints, the redundant quantities are eliminated and the system equations are transformed into equivalent ordinary differential equations. When the system equations do not contain redundant quantities governed by circuit constraints, the system equations are directly expressed as ordinary differential equations. The variable partitioning module is used to divide the state variables in the ordinary differential equation into a first group of state variables and a second group of state variables. The staggered update module is used to acquire the switching signals and the state variables of the current time step during the simulation time step progression, calculate the value of the equivalent controlled source of the current time step through the coupling relationship of the switching signals, update the first set of state variables to the next time step based on the value of the equivalent controlled source of the current time step and the state variables of the current time step using an explicit numerical integration method; and update the second set of state variables to the next time step based on the updated first set of state variables using an explicit numerical integration method, so as to realize the staggered update of the two sets of state variables.

[0017] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to execute the numerical integration method for power electronic circuit simulation described above.

[0018] Fourthly, the present invention provides a readable storage medium storing a computer program, which, when executed by a processor, implements the above-described numerical integration method for power electronic circuit simulation.

[0019] The main contributions and innovations of this invention are as follows: 1. By representing the AC side of the switching bridge arm as an equivalent controlled voltage source and the DC side as an equivalent controlled current source, the power electronic circuit containing time-varying switches is transformed into an equivalent steady system. This makes the symplectic integration method, which was originally not directly applicable to power electronic circuits, applicable. This equivalent modeling method preserves the switching characteristics of the switching devices while eliminating the switching nature of the circuit topology, laying the foundation for subsequent explicit numerical integration methods.

[0020] 2. By employing a redundancy elimination method based on circuit topology analysis, differential algebraic equations that do not satisfy the standard form of ordinary differential equations are transformed into ordinary differential equations containing only state variables through index reduction. During the index reduction process, redundancy is systematically eliminated by identifying constraint structures such as capacitor-voltage source loops and inductor-current source cut sets, ensuring that the transformed ordinary differential equations can be solved using explicit numerical integration methods and avoiding numerical singularities caused by algebraic constraints.

[0021] 3. Borrowing the staggered update strategy of the symplectic integral method, the state variables are divided into two groups based on their physical characteristics: inductor current corresponding to generalized momentum and capacitor voltage corresponding to generalized coordinates. These groups are updated sequentially within each time step, allowing the explicit integration process to better maintain the system's energy conservation characteristics. Compared to the traditional forward Euler method, under the same time length and model parameters, the simulation waveform of this method converges, while the simulation waveform of the traditional forward Euler method diverges, indicating that this method has a significant advantage in numerical convergence.

[0022] 4. This method does not require solving linear equations or iterating at each simulation time step, and the computational complexity is strictly fixed, making it naturally suitable for computational implementation on hardware platforms such as FPGAs. It can meet the requirements of real-time simulation for deterministic computational latency. At the same time, the equivalent controlled source equivalent modeling and index reduction processing are both offline preprocessing steps, which do not consume real-time computing resources.

[0023] Details of one or more embodiments of the present invention are set forth in the following drawings and description, so that other features, objects and advantages of the invention will be more readily understood. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a full-bridge inverter circuit diagram simulated by the numerical integration method for power electronic circuit simulation according to an embodiment of the present invention; Figure 2 It is the equivalent circuit of the full-bridge inverter circuit simulated by the numerical integration method for power electronic circuit simulation according to an embodiment of the present invention. Figure 3 The simulation waveform is obtained by the numerical integration method for power electronic circuit simulation according to an embodiment of the present invention. Figure 4 The simulation waveform is obtained using the traditional forward Euler method; Figure 5 It is a T-type three-level bridge arm modeled according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of this specification. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of this specification as detailed in the appended claims.

[0026] It should be noted that the steps of the corresponding methods are not necessarily performed in the order shown and described in this specification in other embodiments. In some other embodiments, the methods may include more or fewer steps than described in this specification. Furthermore, a single step described in this specification may be broken down into multiple steps in other embodiments; and multiple steps described in this specification may be combined into a single step in other embodiments.

[0027] This invention discloses a numerical integration method for power electronic circuit simulation. Its technical approach includes three core steps: First, equivalent controlled voltage and current sources are used to model the switching arms in the power electronic circuit, transforming the circuit containing time-varying switches into a system equation described by differential algebraic equations. Second, through circuit topology analysis, redundancy is eliminated from the system equations, yielding equivalent ordinary differential equations. Finally, drawing on the staggered update strategy of symplectic integral methods, the state variables in the ordinary differential equations are divided into two groups according to their physical characteristics, and updated sequentially using an explicit numerical integration scheme within each simulation time step. This significantly improves numerical convergence while maintaining the low computational complexity and deterministic computational delay of explicit methods.

[0028] Example 1 This embodiment uses the numerical simulation of a full-bridge inverter circuit as an example to fully illustrate the entire process of the method of the present invention from modeling to numerical integration solution.

[0029] Step 1: Circuit Topology and Equivalent Controlled Source Modeling like Figure 1 As shown, the full-bridge inverter circuit simulated in this embodiment includes switches. , , and Filter inductor and Filter capacitor load resistance DC bus capacitor and DC power supply and DC power supply resistor Among them, the switch and Complementary opening, together forming the bridge arm ;switch and Complementary opening, together forming the bridge arm DC power supply Through DC power supply resistor DC bus capacitor Power supply. Bridge arm The AC side is filtered by an inductor. Connected to capacitor and load resistance One end of the parallel branch, bridge arm The AC side is filtered by an inductor. Connect to the other end of the parallel branch.

[0030] like Figure 1 As shown in the dashed box, the switching devices in the circuit are organized into two bridge arms. and .like Figure 2 As shown, each bridge arm is modeled using an equivalent controlled source: Bridge arm The AC side is represented as an equivalent controlled voltage source. The DC side is represented as an equivalent controlled current source. Bridge arm The AC side is represented as an equivalent controlled voltage source. The DC side is represented as an equivalent controlled current source. . Figure 2 middle and These are the outflowing equivalent controlled voltage sources. and The current, and These are flow filter inductors. and The current, and These are filter capacitors. and DC bus capacitor The voltage on the circuit. The reference directions for voltage and current are in... Figure 2 The symbols are indicated by plus or minus signs and arrows.

[0031] The values ​​of the equivalent controlled voltage source and the equivalent controlled current source are jointly determined by the on / off state of the switching devices in the switching bridge arm and the voltage and current quantities in the circuit. The specific coupling relationship is as follows:

[0032]

[0033]

[0034]

[0035] Among them, the switching signal and Description of switch to On / off state:

[0036]

[0037] Furthermore, the switching devices within the same bridge arm satisfy a complementary control relationship: and Complementary opening, and Complementary opening.

[0038] Setting the filter inductor With filter capacitor The connection point is a node Filter inductor With filter capacitor Another connection point is a node. .

[0039] Step 2: Establish system equations based on Figure 2 Using Kirchhoff's voltage law and current law, write the circuit system equations for the equivalent circuit shown.

[0040] Equation 1 (KVL loop equation): along the path containing the equivalent controlled voltage source Filter inductor and Equivalent controlled voltage source and filter capacitors Write the voltage equation for the loop:

[0041] Equation 2 (KCL node equation): at the filter capacitor The node Write the current equation at the point:

[0042] Equation 3 (KCL node equation): Write the current equation at the DC bus node:

[0043] Equation 4 (Algebraic constraint equation): Based on the filter inductor and Cut set constraints formed by concatenation:

[0044] The above four equations can be written as system equations in matrix form:

[0045] Among them, the system quantities to be solved in the system equations Input quantity Input quantity Includes voltage source and equivalent controlled source Inertia matrix System matrix and input matrix They are respectively:

[0046]

[0047]

[0048] Step 3: Equation Transformation Calculate the inertia matrix of the above system equations. The rank, obtained Since the dimension of the state variables is less than 4, it is determined to be a differential-algebraic equation. Because the index is non-zero, index reduction processing is required to transform it into an ordinary differential equation. Index reduction employs circuit topology analysis methods, specifically including the following three sub-steps: (1) Topology Analysis: Perform topology analysis on the circuit equations to identify the constraint structures formed by components such as capacitors, inductors, voltage sources, and current sources in the circuit. Constraint structures generally include the following two categories: for loops formed by capacitors and voltage sources, identify redundant capacitor voltages or node voltages dominated by voltage constraints; for cut sets formed by inductors and current sources, identify redundant inductor currents or branch currents dominated by current constraints. In this embodiment, the filter inductor... and Forming a series branch, creating a cut set constraint, and determining... Redundancy, system quantity The remaining three quantities, namely It is a state variable.

[0049] (2) Generating ordinary differential equations: Based on Kirchhoff's current law, Kirchhoff's voltage law, and the current-voltage relationship of components, the redundancy is expressed as a function of state variables. In this embodiment, the expression for the redundancy is directly obtained from equation 4:

[0050] Redundancy expression Substitute back into the original system equations. Specifically, substitute into equation 1:

[0051]

[0052] Combining the above equations with equations 2 and 3, we obtain the state variables. Ordinary differential equations:

[0053] in:

[0054]

[0055] In ordinary differential equations, the state variables are circuit quantities with physical meaning. In this embodiment, the state variable is the inductor current. and capacitor voltage , Redundancy eliminated State variables can be used when needed. The above constraints are used to restore the system.

[0056] Optionally, the state variables can also be selected as inductance flux and capacitance charge. For this embodiment, an inductor can be selected. Magnetic Link ,capacitance charge and capacitor charge As state variables, they have the following one-to-one correspondence with the aforementioned current and voltage state variables:

[0057] Substituting this relationship into the aforementioned ordinary differential equation with current and voltage as state variables, we can obtain an ordinary differential equation with magnetic flux and charge as state variables.

[0058] Furthermore, the AC side current and DC side voltage of the switch arm are expressed as functions of state variables. In this embodiment, the switch arm... and The AC side currents are respectively and bridge arm and DC side voltages are all Its value is related to the state variable as follows:

[0059] For ease of explanation, the AC side current and DC side voltage of the switch arm will be collectively referred to as the arm coupling quantity.

[0060] This completes the modeling of the ordinary differential equations for the full-bridge inverter.

[0061] Step 4: Explicit numerical integration with alternating updates Select simulation step size Use subscript In the time-progression simulation, the first... The results of the time step. The state variables in the ordinary differential equations are divided into two groups according to their physical properties: First set of state variables: Inductor current ; Second set of state variables: Capacitor voltage and .

[0062] Within each simulation time step, the following interleaved update process is performed: Step A: Obtain the current state variables and calculate the value of the equivalent controlled source. From the... The current state variable is obtained from the calculation results of the time step. Therefore, the corresponding bridge arm coupling amount can be calculated:

[0063] Right now According to the switch signal and Based on the current bridge arm coupling and coupling relationships, calculate the equivalent controlled source value at the current time step:

[0064] Step B: Update the first set of state variables. Using an explicit numerical integration scheme, update the inductor current based on the state variables at the current time step and the values ​​of the equivalent controlled sources obtained in Step A. To the Time step:

[0065] Step C: Update the second set of state variables. Two implementation methods are provided here, both of which fall within the protection scope of this invention.

[0066] Method 1: Keep the value of the equivalent controlled source obtained in step A unchanged, and combine it with the updated value in step A. The first set of state variables at time step and the second set of state variables at the current time step , The updated version was obtained using an explicit numerical integration scheme. The second set of state variables at the time step:

[0067] Method 2: First, based on the update to the [number]th ... The first set of state variables at time step The second set of state variables at the current time step , Recalculate the bridge arm coupling:

[0068] Right now Based on the recalculated bridge arm coupling and switching signals, the value of the equivalent controlled source is updated according to the coupling relationship:

[0069] Using the updated equivalent controlled source values ​​described above, update the second set of state variables to the next set using an explicit numerical integration scheme. Time step:

[0070] The main difference between Method 1 and Method 2 is: Method 2 first updates the first set of state variables based on the already updated first set of state variables before updating the second set of state variables. The values ​​of switching coupling and equivalent controlled current source were recalculated. and The first method can reflect the impact of inductor current updates on the DC side current of the switch bridge arm more promptly, resulting in more accurate calculation results; the second method directly uses the value of the equivalent controlled current source in step A, which has lower calculation complexity.

[0071] Repeat steps A through C above to perform time-progression simulation until the simulation ends.

[0072] Step 5: Comparison of Simulation Results Figure 3 To use the method disclosed in this invention to Figure 1 The capacitor voltage obtained from the simulation of the full-bridge inverter circuit shown is Waveform that changes over time. Figure 4 To obtain the capacitor voltage using the traditional forward Euler method under the same model parameters, test conditions, and simulation step size. Waveform changing over time. Under constant duty cycle excitation, Figure 3 of The waveform converges to a steady-state value over time, while Figure 4 of The waveform diverges over time. A comparison of the two methods shows that, under the same simulation step size, the method disclosed in this invention has significantly better numerical convergence than the traditional forward Euler method.

[0073] This convergence advantage stems from the staggered update mechanism of this method: By interleaving the inductor current corresponding to the generalized momentum and the capacitor voltage corresponding to the generalized coordinates in time, the explicit integration process can better maintain the energy conservation characteristics of the system, thereby effectively suppressing numerical oscillations and divergences while maintaining the low computational complexity of the explicit method.

[0074] In this embodiment, the explicit numerical integration scheme adopts the forward Euler scheme. In practical applications, those skilled in the art can select other single-step or multi-step explicit numerical integration schemes, such as the improved Euler method, the Runge-Kutta method, etc., according to the accuracy and stability requirements. These schemes are also applicable to the two sets of state variables interleaved update frameworks disclosed in this invention.

[0075] Explicit numerical integration methods can also employ explicit recursive integration methods derived from implicit numerical integration schemes through explicit processing. The explicit processing includes performing algebraic transformations on the implicit numerical integration scheme to obtain an explicit recursive calculation formula for the state variable at the next time step with respect to the state variable at the current time step. The algebraic transformations include one or more of rearranging terms, elimination, matrix inversion, or matrix factorization. For example, regarding step B of this embodiment, method one can... Using an implicit numerical integration scheme, the following recurrence equation is obtained:

[0076] In the equation It appears on both sides of the equals sign, therefore it belongs to the implicit format. Algebraic transformations can then be used to... Moving the terms to the left side of the equals sign, we get:

[0077] Further matrix inversion and simplification yields the following explicit recursive formula:

[0078] in and It is the coefficient matrix of the explicit recursive formula:

[0079]

[0080] Wherein, the coefficient matrix and These are all constants, unaffected by the circuit switching state, and therefore can be pre-calculated before the simulation begins, without occupying the computation time of each time step in the real-time simulation. This achieves a computational time complexity comparable to explicit numerical integration methods, and is also within the scope of the claims. In practical applications, those skilled in the art can, according to accuracy and stability requirements, employ explicit recursive integration methods—obtained by explicit processing of implicit numerical integration schemes—for any state variable at any step of the state variable interleaving update process. These schemes are also applicable to the two sets of state variable interleaving update frameworks disclosed in this invention.

[0081] Example 2 This embodiment uses a T-type three-level bridge arm as an example to illustrate the application of the equivalent controlled source modeling step in the method of the present invention in multi-level topologies, so as to demonstrate the applicability of the method of the present invention to different power electronic circuit topologies.

[0082] like Figure 5 As shown, the T-type three-level bridge arm includes a switch. , , and and DC bus capacitor and The DC side of this bridge arm uses two equivalent controlled current sources. and This indicates that an equivalent controlled voltage source is used on the AC side. express. and They are capacitors and The voltage on, It is an outflowing equivalent controlled voltage source The current.

[0083] switch to The on / off state determines the switching signal. and :

[0084]

[0085] Furthermore, the value of the equivalent controlled source has the following coupling relationship with the switching signal:

[0086]

[0087]

[0088] in and They cannot both be 1 at the same time.

[0089] Unlike the single-capacitor DC bus structure in Embodiment 1, this embodiment has two series-connected voltage-dividing capacitors on the DC side. and AC-side equivalent controlled voltage source The value is determined by the voltages of the two DC-side capacitors. and The voltages are multiplied by their respective switching signals and then summed to reflect the characteristics of the T-type three-level bridge arm outputting positive, zero, and negative voltages under different switching states. Two equivalent controlled current sources on the DC side. and The current flows through the corresponding DC bus capacitors, reflecting the distribution relationship of DC bus current under different switching paths.

[0090] By utilizing the coupling relationship between the aforementioned switching signal and the DC-side voltage, AC-side current, and equivalent controlled source, the T-type three-level bridge arm can be substituted into the power electronic circuit network containing the bridge arm to form the corresponding system equations. Subsequently, following the same method as in Example 1, redundancy can be eliminated through topology analysis to transform the system equations into equivalent ordinary differential equations, which can then be solved using an explicit numerical integration method with staggered updates.

[0091] The above two embodiments demonstrate that the equivalent controlled source modeling method disclosed in this invention is not only applicable to two-level bridge arms (such as the full-bridge inverter in Embodiment 1), but also to multi-level topologies such as three-level bridge arms, and has good topology universality.

[0092] Example 3 Based on the same concept, this invention provides a numerical integration system for power electronic circuit simulation, comprising: The equivalent modeling module is used to perform equivalent modeling of the switching bridge arm in the power electronic circuit, and to represent the switching bridge arm as an equivalent controlled source, wherein the AC side of the switching bridge arm is represented as an equivalent controlled voltage source and the DC side of the switching bridge arm is represented as an equivalent controlled current source. The equation construction module is used to construct system equations describing the dynamic behavior of the power electronic circuit based on equivalent modeling and circuit connection relationships. The equation transformation module is used to analyze the system equations. If there are redundant quantities governed by circuit constraints, the redundant quantities are eliminated and the system equations are transformed into equivalent ordinary differential equations. When the system equations do not contain redundant quantities governed by circuit constraints, the system equations are directly expressed as ordinary differential equations. The variable partitioning module is used to divide the state variables in the ordinary differential equation into a first group of state variables and a second group of state variables. The staggered update module is used to acquire the switching signals and the state variables of the current time step during the simulation time step progression, calculate the value of the equivalent controlled source of the current time step through the coupling relationship of the switching signals, update the first set of state variables to the next time step based on the value of the equivalent controlled source of the current time step and the state variables of the current time step using an explicit numerical integration method; and update the second set of state variables to the next time step based on the updated first set of state variables using an explicit numerical integration method, so as to realize the staggered update of the two sets of state variables.

[0093] Example 4 This embodiment also provides an electronic device, see reference. Figure 6 It includes a memory 402 and a processor 401, the memory 402 storing a computer program and the processor 401 being configured to run the computer program to perform the steps in any of the above method embodiments.

[0094] Specifically, the processor 401 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of the present invention.

[0095] The memory 402 may include a mass storage device for data or instructions. For example, and not limitingly, the memory 402 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 402 may include removable or non-removable (or fixed) media. Where appropriate, the memory 402 may be internal or external to a data processing device. In a particular embodiment, the memory 402 is non-volatile memory. In a particular embodiment, the memory 402 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random Access Memory (FPMDRAM), Extended Data Out Dynamic Random Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0096] The memory 402 can be used to store or cache various data files that need to be processed and / or communicated, as well as possible computer program instructions executed by the processor 401.

[0097] The processor 401 implements any of the methods described above by reading and executing computer program instructions stored in the memory 402.

[0098] Optionally, the electronic device may further include a transmission device 403 and an input / output device 404, wherein the transmission device 403 is connected to the processor 401 and the input / output device 404 is connected to the processor 401.

[0099] The transmission device 403 can be used to receive or send data via a network. Specific examples of the network described above may include wired or wireless networks provided by the communication provider of the electronic device. In one example, the transmission device includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 403 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0100] Input / output device 404 is used for inputting or outputting information. It can be a speaker, microphone, monitor, or keyboard.

[0101] Example 5 This embodiment also provides a readable storage medium storing a computer program, the computer program including program code for controlling a process to execute the process, the process including the method according to Embodiment 1.

[0102] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0103] Generally, various embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention can be implemented in hardware, while others can be implemented by firmware or software executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the invention may be shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, by way of non-limiting example, these blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0104] Embodiments of the present invention can be implemented by computer software, which may be executable by a data processor of a mobile device, such as a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products), including software routines, applets, and / or macros, can be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. A computer program product may include one or more computer-executable components configured to perform embodiments when the program is run. One or more computer-executable components may be at least one piece of software code or a portion thereof. The software may be stored on physical media such as memory chips or blocks of storage implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as, for example, DVDs and their data variants, CDs, etc. The physical media are non-transient media.

[0105] In the above embodiments, a full-bridge inverter circuit and a T-type three-level bridge arm were used as examples for illustration. In fact, the method disclosed in this invention can be applied to any power electronic circuit topology that includes a switching bridge arm, including but not limited to various inverters, rectifiers, DC-DC converters, etc.

[0106] In the above embodiments, the performance degradation processing targets the redundancy caused by the cut-set constraints formed by inductors and current sources (i.e., in Embodiment 1). For circuit topologies containing loop constraints formed by capacitors and voltage sources, the redundancy elimination method disclosed in this invention can also be used to reduce performance, representing the corresponding redundant capacitor voltages or node voltages as functions of state variables and eliminating them.

[0107] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A numerical integration method for power electronic circuit simulation, characterized in that, Includes the following steps: Equivalent modeling is performed on the switching bridge arm in the power electronic circuit, and the switching bridge arm is represented as an equivalent controlled source, wherein the AC side of the switching bridge arm is represented as an equivalent controlled voltage source, and the DC side of the switching bridge arm is represented as an equivalent controlled current source. Based on the equivalent modeling and circuit connection relationships, a system equation describing the dynamic behavior of the power electronic circuit is constructed. The system equations are analyzed. If there is redundancy governed by circuit constraints, then quantities other than the redundancy that can characterize the dynamic degrees of freedom of the power electronic circuit are selected as state quantities. Based on the circuit constraint relationship, the redundancy is expressed as a functional expression of the state quantities, and the functional expression is substituted back into the original differential algebraic equation to eliminate the redundancy, thus transforming the system equations into equivalent ordinary differential equations. When the system equations do not contain redundancy governed by circuit constraints, the system equations are directly expressed as ordinary differential equations. Among them, redundant capacitor voltage and / or node voltage, and redundant inductor current and / or branch current are used as redundancy. The state variables in the ordinary differential equation are divided into a first group of state variables and a second group of state variables. During the simulation time step progression, the switching signal and the state quantity of the current time step are acquired. The value of the equivalent controlled source in the current time step is calculated through the coupling relationship of the switching signal. The first set of state quantities is updated to the next time step based on the value of the equivalent controlled source in the current time step and the state quantity of the current time step using an explicit numerical integration method. Based on the updated first set of state variables, the second set of state variables is updated to the next time step using an explicit numerical integration method, so as to achieve the interleaved update of the two sets of state variables.

2. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, The switching signal coupling relationship includes: The value of the equivalent controlled voltage source is determined by coupling the switching signal of the switch arm with the DC side voltage of the switch arm; the value of the equivalent controlled current source is determined by coupling the switching signal of the switch arm with the AC side current of the switch arm.

3. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, Analyzing the system equations, if there is redundancy governed by circuit constraints, including: Identify the loops formed by capacitors and voltage sources in the power electronic circuit, and determine the redundant capacitor voltages and / or node voltages governed by voltage constraints; Identify the cut sets formed by inductors and current sources in the power electronic circuit, and determine the redundant inductor currents and / or branch currents governed by current constraints.

4. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, The state quantities are circuit quantities with physical meaning, including inductor current, capacitor voltage, inductor flux linkage, and capacitor charge.

5. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, The grouping method for the first group of state variables and the second group of state variables adopts one of the following combinations: (1) The first set of state variables is inductor current or inductor flux linkage, and the second set of state variables is capacitor voltage or capacitor charge. (2) The first set of state variables is capacitor voltage or capacitor charge, and the second set of state variables is inductor current or inductor flux linkage.

6. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, The process of updating the second set of state variables to the next time step using an explicit numerical integration method based on the updated first set of state variables includes: Keeping the value of the equivalent controlled source unchanged at the current time step, the second set of state variables updated to the next time step is calculated using an explicit numerical integration method, in combination with the first set of state variables updated to the next time step and the second set of state variables at the current time step.

7. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, The process of updating the second set of state variables to the next time step using an explicit numerical integration method based on the updated first set of state variables includes: Based on the first set of state variables updated to the next time step and the second set of state variables at the current time step, the value of the equivalent controlled source is recalculated through the switching signal coupling relationship. Combining the first set of state variables updated to the next time step and the second set of state variables at the current time step, the second set of state variables updated to the next time step is calculated using an explicit numerical integration method.

8. The numerical integration method for power electronic circuit simulation as described in claim 1, characterized in that, The explicit numerical integration method includes a direct explicit numerical integration method and / or an explicit recursive integration method obtained by explicitening an implicit numerical integration scheme; the explicitization process includes performing an algebraic transformation on the implicit numerical integration scheme to obtain an explicit recursive calculation formula for the state variable of the next time step with respect to the state variable of the current time step; the algebraic transformation includes one or more of the following: rearranging terms, elimination, matrix inversion, or matrix decomposition.

9. A system for implementing the numerical integration method for power electronic circuit simulation according to any one of claims 1 to 8, characterized in that, include: The equivalent modeling module is used to perform equivalent modeling of the switching bridge arm in the power electronic circuit, and to represent the switching bridge arm as an equivalent controlled source, wherein the AC side of the switching bridge arm is represented as an equivalent controlled voltage source, and the DC side of the switching bridge arm is represented as an equivalent controlled current source. The equation construction module is used to construct system equations describing the dynamic behavior of the power electronic circuit based on the equivalent modeling and circuit connection relationships. The equation transformation module is used to analyze the system equations. If there are redundant quantities governed by circuit constraints, quantities that characterize the dynamic degrees of freedom of the power electronic circuit, other than the redundant quantities, are selected as state quantities. Based on the circuit constraint relationship, the redundant quantities are expressed as functional expressions of the state quantities, and the functional expressions are substituted back into the original differential algebraic equations to eliminate the redundant quantities, thus transforming the system equations into equivalent ordinary differential equations. When the system equations do not contain redundant quantities governed by circuit constraints, the system equations are directly expressed as ordinary differential equations. The variable partitioning module is used to divide the state variables in the ordinary differential equation into a first group of state variables and a second group of state variables. The staggered update module is used to acquire the switching signal and the state quantity of the current time step during the simulation time step progression, calculate the value of the equivalent controlled source of the current time step through the coupling relationship of the switching signal, and update the first set of state quantities to the next time step based on the value of the equivalent controlled source of the current time step and the state quantity of the current time step using an explicit numerical integration method. Based on the updated first set of state variables, the second set of state variables is updated to the next time step using an explicit numerical integration method, so as to achieve the interleaved update of the two sets of state variables.

10. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the numerical integration method for power electronic circuit simulation as described in any one of claims 1 to 8.

11. A readable storage medium, characterized in that, The readable storage medium stores a computer program that, when executed by a processor, implements the numerical integration method for power electronic circuit simulation as described in any one of claims 1 to 8.

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